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Blenheim operating limits and checklists
After scouring left and right for a Blenheim mk.IV manual or pilot's operating handbook and finding nothing freely available, today i stumbled upon the POH for the Mk.V variant.
I just finished reading through it and while there are certain differences in the placement of controls and gauges, it uses the same engines as the Mk.IV we have in the sim. There are also a lot of stuff that are half-way modeled in the sim (they are modeled but work automatically without input from the player) and it sheds some light on those too. For example, it says that there is an engine operated hydraulic pump but it can't provide sufficient hydraulic pressure for all systems, so there's a hydraulics selector valve for it. It can be set to provide hydraulic pressure to either gear and flaps or the turret, but not both at the same time. It also has an off switch to prevent it from overheating during cruise. So, a pilot would take off with hydraulics set to gear/flaps, cruise with them switched off and then switch it to provide power to the turret when nearing dangerous airspace. This is probably why the turret is inoperable in the sim when the aircraft is on the ground. There is also mention of a reconnaissance camera and this is also visible in our Mk.IV: go to the gunner's station, press the key that opens the canopy and switch to external view, you will be able to see an opened hatch on the top of the fuselage slightly ahead of the turret and through this opening the camera is visible. I hope it becomes operable at some point. So, on to the important stuff, engine operating limits. The Mk.V comes equipped with either mercury XV or 25 engines. The manual gives the exact same limits for both, the only thing that's different is the oil temps. Our in-game MkIV uses mercury XV engines, so the various settings should be the same. However, the most important difference is that the Mk.V comes equipped with constant speed propellers (20 degrees of motion, plus the ability to lock them in full coarse pitch for cruise by pulling the levers fully back, just like our Rotol Hurricane in the sim). Our in-game Mk.IV has the simpler two-stage props, so we won't be able to match the limits exactly because we lack precise control over RPM. The boost cut-out is said to give a maximum of +9 boost when it's on, +5 when it's disabled. That being said, here's the deal: Maximum takeoff power to 1000ft, 3 minutes limit: with 100 octane fuel: +9 boost 2750 RPM with 87 octane fuel: +5 boost 2650 RPM Max. climb power, 30 minute limit: regardless of fuel octane rating +5 boost 2650 RPM cylinder head temps (CHT) at 210C oil temps at 80C Max. continuous power (no time limit) for rich mixture: regardless of fuel octane rating +3.5 boost 2400 RPM CHT at 190C oil temps at 70C Max. continuous power (no time limit) for weak (lean) mixture: regardless of fuel octane rating +1.5 boost 2400 RPM CHT at 190C oil temps at 70C Max. all out limit (war emergency power): with 100 octane fuel: +9 boost 2750 RPM CHT at 235C oil temps at 90C 30 minutes time limit with 87 octane fuel: +5 boost 2750 RPM 5 minutes time limit Diving Restrictions: maximum boost +5 maximum RPM 3120 exceeding 2750 RPM permitted only for 20 seconds with the throttle not less than 1/3rd of the way open Indicated Airspeed (IAS) restrictions: Diving 325 mph Gear down 140 mph Flaps down 125 mph Clearance for bomb drop with 500lb bombs (no idea about the 250lb ones): Dive 55 degrees Climb 40 degrees Bank 10 degrees Exceeding these during a bomb drop probably means that your bombs will bounce around inside your own aircraft. Carb heat use: (i) Set to on: a) For all flying at less than +3.5 boost, unless the ambient air temperature is above +15C. When it is higher than +15C, turn it off regardless of boost settings. b) For all flying (irrespective of boost and atmospheric temperature) in conditions of high humidity, in or just below clouds, in rain, snow or sleet. It can also be used to help warming up the engines in very cold weather. (ii) Set to off for all other conditions including: (a) Engine start at all times (seems contrary to what we've been doing in-game so far) (b) Take off (c) Landing, except in the high humidity conditions described above in point (i)b) Lots of other interesting stuff in the manual as well. For example, starting and shutting down the engines is done with the props at coarse pitch instead of fine, it mentions it's longitudinally unstable and that trim should be set slightly nose down for take-off (probably to help raise the tail faster). I will link the complete manual to be hosted at airwarfare.com as long as their site admin (Gamekeeper?) can assure me there's no copyright troubles involved on their end. Until then, have fun with the abbreviated checklists above, cheers ;) |
Great stuff thx
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Great info :)
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Thx, VERY interesting summary!!!
I will copy these limits in my personal Pilots Handbook i am writing for every plane :) |
Updated and corrected information.
A helpful community member sent me a copy of a Blenheim Mk.IV pilot's operating handbook. I'm probably being a bit paranoid, but since it is copyrighted material i'd rather not name him nor link it directly so that we don't draw any flak on the guy and the admins/forums. What i can do is copy the relevant parts here.
Controls and what's different between the real and the in-game Mk.IV: Propellers: The real Mk.IV has two-speed propellers. In the sim it has the correct propellers but the slider/control behaviour is wrong. We can move the prop pitch controls through their entire range of travel but it has no effect for the most part: setting it fully aft sets full coarse pitch, setting it to anything higher than that sets full fine pitch. You can easily see this for yourself when sitting on the ground with the engines off, just pull the controls forward/aft a couple of times and watch how the propeller blades change their pitch. In other words, there's absolutely no reason to set it about 50% of the way, it has no effect and it's still running full fine unless you pull the controls all the way back. What the manual recommends: Fine pitch for takeoff, climbing on one engine and approach for landing. Coarse pitch is to be used for all other phases of flight, unless the engines are throttled way back in which case fine pitch might be needed to prevent rough running/way too low RPM. Mixture: Mixture in the real one is semi-automatic. The mixture control positions on the throttle quadrant are labeled normal (for auto rich) and weak (for auto lean). In the sim we can again move the controls through the entire range of motion. I don't know if this means the mixture is semi-auto and it's just the top and bottom positions of the control that matter. It could be that the mixture is fully manually adjustable which would probably be wrong. There were two different types of carburetors fitted, but the manual doesn't state any of them being a manually operated type. In any case, how mixture works is difficult to test in the sim because we don't have the kind of immediate feedback we can get with the propellers. There is also a very strong possibility that it is modeled correctly with a strong attention to detail. The manual states "each mixture control lever has two effective positions only", which could very well mean that it could move through the entire range with half of the lever's travel range corresponding to auto lean and the other half to auto rich. The mixture controls in the sim are reversed as in every other RAF aircraft, not only in regards to animation but keymapping/controller usage as well: you need to press your "decrease mixture" key or pull your HOTAS sliders back to move it towards auto-rich. What the manual recommends: Use auto rich (labeled "normal" on the in-game throttle quadrant, levers aft) when running more than +1.5lbs of boost. Use auto lean (labeled "weak", levers forward) when running less than +1.5lbs of boost. The mixture levers snap back to the normal/auto-rich position when closing the throttles to prevent rough running, just like in the Hurricane, but i don't remember if this is reflected in the sim. Flaps, gear and hydraulics: The hydraulics (flaps, gear and turret) are driven by a pump which is in turn driven by the port engine. If you lose or have to switch off the port engine you must set the flaps/gear controls to the desired position and then use (as in ,repeatedly click on) the emergency hand pump in the cockpit, situated to the right of the pilot's seat. The engine driven hydraulic pump is not powerful enough to drive everything at once, it's either the turret or the flaps and gear. This explains why the turret refuses to move when the aircraft is on the ground, the sim models the correct procedure without input from the player. In reality they could even switch off the pump completely to prevent it from overheating. Flaps in the real Mk.IV were adjustable. In the sim we only have fully retracted or fully extended flaps (much like the Spitfire), but it should probably work more like the Hurricane, with up, neutral and down positions so that you can set it to neutral mid-way through the extension sequence and get partial flap extension. What the manual recommends: Use 15 degrees of flaps when the outboard tanks are full for long range missions (14500lbs total weight), they are not essential for lighter load-outs (up to 12600lbs total weight). This is why when turning on the autopilot/handing control to the AI you see them flipping like mad between flaps up and down, they are trying to get partial flaps. Until we get a revised flap control logic for the Blenheim, we can't use partial flaps in the sim. Maximum speed with the gear down is 130mph IAS. Cowl flaps: During normal flight they allow enough air to pass through to cool the engines even when they are set to the fully closed position. They must be open for ground running to prevent overheating when there's no airflow to cool the engines. For climb, high speed (probably meaning high power settings) and flying in warm weather they should be partially open. Keep closed as much as possible to minimize drag, unless the cylinder temperatures (the two instruments on the right cockpit wall above the fuel selector switches/wheels) are climbing above specified limits (to be given further on down, keep reading ;) ) Boost over-ride: Similar to the boost cut-out in Spits and Hurris, the lever on the instrument panel to the right of the RPM gauges. Used for takeoff when the aircraft is configured for long range flight and thus heavier (outboard tanks filled, 14500lbs total weight). When activated, it raises maximum available boost from +5 to +9lbs. As you may have guessed this needs 100 octane fuel. Important: Interestingly enough, since +9lbs is only to be used for takeoff when the outboard tanks are full, only these outboard tanks carry 100 octane fuel. This could even explain why some people have more trouble taking off than others. The default loadout has all tanks filled up. If the difference in octane ratings is modeled in the sim it's very important to execute the takeoff with the outboard tanks selected as this enables us to use the boost over-ride for an extra 4lbs of boost, then switch to the inboard tanks once the boost over-ride has been disabled and we are running normal boost values again. Various controls: There's a fuel dump switch for the outboard wing tanks to the left and behind the pilot, right there with the carb heat and pitch controls that are obscured by the pilot's seat. You can only jettison fuel from the outer tanks (which are only filled up for long range missions), so the suggested procedure is to use up the inboard tanks first. I don't know if this is functional in the sim. The third fuel selector is used for cross-feeding. If you need to shut down an engine you turn on this fuel selector and the remaining engine is fed from the tanks on both wings, so that you don't get an imbalanced airframe with more weight on the "dead engine" wing. In general, it should be left to the off position in most other circumstances. Trim tabs should not be used to assist in maneuvering, especially dive recovery, as they can cause overstress of the airframe. The brake lever could be locked in the "down" position, effectively functioning like a parking brake, pressing the lever again unlocked it. I don't know if this is reflected in the sim, it would be very useful if it was because we wouldn't have to keep the brakes pressed while warming up our engines. I'll cut off here and supply the engine operating limits in the next post for ease of reading (this one's a wall of text as it is). |
I always end up postponing this, but i see a lot of people have many questions.
I finally decided to bite the bullet and do it, these are the most important bits as a quick and dirty reference ;) So, without further ado, here are the Blenheim MK.IV operating limits and abbreviated checklists, according to the proper Mk.IV pilot's operating handbook: Take-off:
Climb:
Cruise:
Diving:
Landing:
Missed Approach and Go-around:
After landing:
Engine Limits:
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the coarse pitch setting i dont use, at least not at height till ~6000ft.
the rpm i can achieve with coarse pitch are so low , even with 100% throttle, the temperatures become too low. I only use fine pitch in CoD's Blenheim :( |
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Thank you very much for another great piece of writing about the planes in this sim and the Blennheim in particular. Looking forward to the engine limitations. I got a rough idea as to what they must be, be nice to see it confirmed. Thanks again Blackdog. :cool: Bando |
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how do you lock the brake ? |
The only way I've found to keep the engines running while airborne is fly as follows:
-Full Boost +5 (full throttle) to heep Oil Temp at least 40 C. Anything less than full boost and oil temps fall to below 40 and things die. -Full coarse pitch: To keep rad temp below 230 C I need to keep RPM's low to 1600 etc, otherwise rad overheats. -Cowl flaps full open: to keep rad temp below 230 C. Mixture full lean seems to have no effect, mind you I haven't been higher than 6000 ft. I've tried running with 60-70% throttle but then boost is too low and oil temp dies off. What am I doing wrong here? Nothing I've tried other than the above can keep the big bird in the sky. Is it somewhat broken? I don't want to turn off CEM or disable engine temp management. |
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When I need to brake slow, this lever helps as well. For the amount of "breaking power" is equal to the amount of "travel" on the lever. Hope it makes sense. |
ah, ok, you have the brake on a slider/axis.
Something to think about, i also use the MSFFB2 (with X52PRO Throttle) and the MSFFB throttle is in no use in the moment.... |
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============================ http://en.wikipedia.org/wiki/Aircraf...tle_of_Britain ........ 100 octane aviation fuel As early as 1938 Roy Fedden, who designed most of the Bristol Engine Company's most successful aero engines, pressed for the introduction of 100 octane aviation spirit from the USA.[23] During 1938 the British aero engine manufacturers Bristol and Rolls-Royce demonstrated variants of their 'Mercury' and 'Merlin' engines rated for 100 octane fuel[24][25] ........ Notes 1. ^ In September 1939 Bristol Blenheim Mk IVs of several squadrons of Bomber Command (18, 21, 57, 82, 90, 101, 107, 110, 114 and 139 Squadrons) were being converted to use Bristol Mercury XVs and to carry additional fuel tanks for 100 octane fuel in their outer wings. This work was completed by 7 October.[29] ============================ and ============================ http://en.wikipedia.org/wiki/Bristol_Mercury ............... Mercury XV (1938) 825 hp, developed from Mercury VIII. Converted to run on 100 Octane fuel (previously 87 Octane). ============================ Could it have run on 87 as well? |
Well, it's in your own quote ;)
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1) We need more range 2) We add two more fuel tanks 3) Plane is now heavier so we need more power 4) Modify the engines to run higher boost 5) Higher boost needs better fuel 6) Fill the outboard tanks with 100 octane 7) Use outboard tanks for takeoff and emergency power 8 ) Use inboard tanks during cruise because the power settings are lower and there's less risk of detonation I'm not an engineer mind you, just going by what the manual says. Everything in the manual points to the fact that the engines could switch between 87 and 100 octane mid-flight without problems, as long as the correct boost limits for each fuel type were observed to prevent detonation. As for the rest of the checklists, sorry for the delays but i've had a bit of a busy week. I don't want to just copy things over, so i'm taking the time to format it in an easy to read manner. The manual mentions a lot of stuff in detail and then provides abbreviated limitations, or gives additional information in a different section. What i'm trying to do is fuse that information together in a way that's easy to read and follow. The end result is shortened checklists that contain only the stuff applicable to the game for all relevant systems. For example, i make no mention of hydraulic pump operation because even though it's modeled in the sim, its operation is automatic. I do this separately for every phase of flight (start up, warm up, taxi, take off, cruise, etc), so it needs quite a bit of back and forth though the pages. As you can guess it's taking some time, but i might be able to have it done and posted during the weekend. |
Thanks BlackDog.
I tried the Blenheim the other night and it was just a pain to get off the ground, especially not knowing why (like using the outer 100 octane fuel tanks). Also need to know those max boosts for each. Some of our guys want to try it although I'm not mad on the idea :) Look forward to more of your info. |
Well, just to get you started:
Takeoff at full fine pitch. I don't know if the sim models the different fuel in the outboard tanks. The real life drill is to select outboard tanks, set the boost cut-out to on and give it +9 lbs boost while doing what is by now common knowledge to keep it from veering to the right (brake and left rudder to force left wheel braking, more throttle on the starboard engine and less on the port one), until you get sufficient speed that your rudder becomes effective. In one of Freycinet's videos you can also see a different method. He only gives it about 60% throttle which lessens the drifting to the right, until the airspeed rises and the rudder is again effective. Then you can advance both throttles to full, lay off the brakes and keep it going straight with the rudder. Lift off at about 80-100mph but don't climb. Retract gear and disable the boost cut out (which lowers your maximum boost to +5 lbs) to keep your engines healthy. Once you reach 120mph go to coarse pitch (pull the pitch levers all the way back, anything above that qualifies as fine pitch so if you just set it to 50% of the way you're still running full fine and high RPM). Once you reach 150mph you can start climbing. Max climb is +5 lbs and about 2600-2700 RPM (going from memory here) but i don't know how the in-game CEM agrees with that. In any case, even the manual recommends climbing at lower settings for economy reasons so it should be perfectly possible. Max continuous is +1.5 lbs for lean mixture and +3.5 (if i'm not mistaken) for rich mixture. Once again, mixture is either auto lean or auto rich, there are no in-betweens. In this case however the full-range motion of the levers is historically correct, you just set them according to the demarcation labels on the throttle quadrant. Lean is with the levers forward and rich is with the levers back. To cut a long story short, as soon as you lift off raise your gear, level out, go to coarse pitch once you hit 120mph, disable the boost cut-out and throttle back to +3.5 lbs boost. When you hit 150 mph trim it for climb, start monitoring your engine temps (you might need to close the cowl flaps a bit, this will also give you some more speed and a better climb) and give yourself a pat on the back. You might also want to switch to the inboard tanks once you're established in the climb, just to start learning good habits for when the different fuel is modeled (if it's not already). Another reason for this is that only the outboard tanks have the ability to jettison fuel (again, i haven't tested if this is modeled in the sim), so it makes sense to first burn the fuel you can't dump in an emergency during cruise to maximize on saving weight in such a case. Once you reach your chosen cruising altitude and trim for level flight, throttle back to +1.5 lbs boost and set mixture to auto lean (levers full forward) to maximize your fuel economy. |
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Don't know if this will help or not but I'm attaching some info I got from reading the Blenheim MkV pilot's notes. Ours is the MkIV but the engine is the same (Mercury XV)
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in my experience so far, i dont use coarse pitch at all. I dont get enough rpm to keep the engine at needed temperature with coarse :D
I fly only fine pitch, and reduce throttle to keep rpm and temperature in the games desired limits... |
In case you were still wondering I got a reply from the Blenheim Society on the two fuels in the Blenheim:
...... has passed me your query re fuel of different octane ratings used in the Blenheim IVs. Yes they did have two different fuels in the same aircraft! 100 octane in one pair of tanks used for take-off and emergencies with a 'Plus 9 lbs boost' lever, and a lower octane fuel for far less boost pressure, used for cruising, in another pair, and of course this did lead to many accidents, often fatal. How this came about is explained in detail in my book "The Bristol Blenheim - a complete history" published by Crecy. You can buy one at the discounted price of under £30 for Blenheim Society members from Ron Scot the Society Hon. Treasurer on 01 992 442 608 or borrow one from a public library. Seems to me one or more of your group could join the Society at £15pa as they publish an excellent Journal, and have an annual Blenheim Day and lunch at Duxford with access to the actual aircraft and opportunity to meet the few remaining wartime crew and the present day engineers. Regards Graham Warner Enthusiasts may like to buy his book and even join their society :) |
Excellent information, impressive detail.
Now, coming back to reality, why can I not start the frigging engine? :( fuel cocks (the round things on the right) on magnetos on throttle @20% carb heater on (off did not make a difference either) mixture middle select engine #0 press I to start It turns and dies :( ~S~ |
Try 10% throttle and FULL rich mixture ( digital infowondow reading is 0% !!)
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T h a n k s! :)
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Sorry for continuing with the stupid questions but progress is reaaaaly slow :(
Solved the problem of the engine startup, it was because I flying with little fuel in order to ensure take off but both fuel cocks' first setting was switching to the (empty) outer tanks... OK, first problem solved, second was quick to come: In front of me at the cockpit I see the Oil Temp gauges. I have to wait for the oil temp to reach 60°C in order to have proper rpm response from the motors (otherwise the rpm needles tend to "yo-yo" up and down). where is the engine temperature (air cooled engine) Does it play any role? What is the RPM limit for the engines? My problem is that after takeoff, I get very quickly a grosvenor failure and afterwards things take their downturn... :( ~S~ |
Engine temps are behind your right shoulder above the fuel cocks. I find engine temp is critical in the Blenheim, keep it above 200 and below 275. Max rpm I don't know but I try not to go above 2500ish.
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Nicely hidden! :) thanks! |
Does Blenheim have the one-stage compressor modelled at all?
Seems impossible now to climb above 5-6k feet now. Compared to Accu-sims P-47, the Cod engines are not any near realistic at temperatures. Can even make a runway takeoff (no taxiing), without using cowlings. http://i466.photobucket.com/albums/r...t/FSX/P-47.jpg |
Actually, taking off with the cowl flaps closed is recommended in the pilot's notes for the Blenheim Mk.IV, they are supposed to be effective enough in terms of airflow getting through the engine once you start moving.
I'm sorry for pushing this back guys (i've been spending some time on other real life stuff lately and other aspects of the sim), i will try to finalize my copying of the relevant manual pieces and post it here sometime within the next couple of weeks :-P |
AFAIK the Engine head temperatures (asuming engine temps are sylinder head temps), arent they also depending on fuel mix, and not just airflow/rpm?
Is it modelled in this game/sim? Shouldn't setting correct mix, also increase rpm slightly, like in RoF? |
AFAIK it has only auto rich and auto lean mixture setting...
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This is not a glitch with CoD, the Mk.IV pilot's operating handbook describes how the real aircraft uses such a system. |
Endless trouble with the Blenheim
Well, I've just about tried every combination of mixture, carb heating, pitch, gills (radiator flaps), throttle... and I always get engine failures as I climb out.
I eventually discovered that the lean/rich setting seems to be exactly as labelled next to the lever, fully back seems to be auto rich. I warm the engine with gills open (as per Klem's excellent pdf posted above), but takeoff with them open, or temps get too high (contrary to Klem's info). I use the 100 octane outer tanks (contrary to Klem's info). I allow the engine oil temp to get above 40C before revving a little. I cycle the prop pitch before taking off to circulate oil. When I take off, I DON'T engage boost override and limit to about 4 lbs boost - that seems to get rid of most of the failures on takeoff - keeping revs below about 2500 and VERY gently increasing throttle. As soon as I'm wheels-up I reduce throttle to about 0 boost and it seems to run sweetly on about 2200 rpm. So I get off the ground OK with this recipe, but then I always get gasket failures, governor failures etc at around 2000ft - this is despite closing gills to keep temps up and adding some carb heat. What am I doing wrong?! 56RAF_phoenix |
my only advice would be, try lower rpms and always keep the engine temperaturebetween 200° and 250°.
i personaly never swith to course pitch, i always stay in fine and control the rpm with throttle. and yes, in the british planes (Tiger Moth i dont know) full rich mixture is 3D cockpit lever full back, with whatevercontrol setting you get this. Digital info mixture reading is 0% (or mixture bar down) than ! |
My thinking is: governor failures are because oil at the right temperature is not getting to the pitch mechanism; gasket failures are because oil or cylinder pressure or temperature is too high (maybe because I'm running at too low revs for the throttle setting); carburetta failures because it needs heat.
But maybe that's too simplistic? I did notice, when incorrectly running too lean, that it was impossible to have oil temps and cylinder temps both correct. 56RAF_phoenix |
there is no governor (at least that is my understanding how propellers are working......), the Blenheim IV has no CSP, only a two speed propeller.
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Ive looked hard at all the advice listed in previous posts please please can someone who is an expert post..a concise..takeoff ,level flight,and combat settings for this plane...TY a head of time
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I've tested the blenheim for quite a long time, (because it's the only red bomber) and came up with some "interresting" issues:
I've put this results in another bug explanatory thread but I think it will be usefull to put it here aswell CEM: Mixture doesn't work at all. I tested it high and low and it's have no effect on temperature, exhaust gas, fuel consumption or anything. And when you set the throttle to 0 no mather what mixture settings you have, it will exhaust black smoke. Also the lever works inversely like in the hurricane. Prop pitch seems to be two stage in the 3D modell. (on 0 pitch input it turns right to a more featherd position, on anything else than 0 it turns left to its takeoff position. You can observe it when the engines are stoped) However, it have a full effect on rpm in different positions (not just two stages) as I measured: Throttle 75 % IAS 200-210 mhp Height 8000ft Radiator 100% Carburetor heat 100% Pitch % / RPM 100 / 2660 75 / 2520 50 / 2320 25 / 2120 0 / 1760 Carburetor heat seems to work inversely. In 100% you'll get less engine temperature then in 0% Throttle 50 % Pitch 75% IAS: 150-160 mph Height: 8000 ft Radiator 100 % Carburetor heat % / Engine temperature °C / RPM 100 / 201 / 2260 75 / 203 / 2290 50 / 208 / 2340 25 / 221 / 2380 0 / 233 / 2480 Also the carburetor heat controll lever labeld as "AIR INTAKE SHUTTER" (Don't really know how it suppose to work on this airplane) Boost cut-out doesn't have any effect on engines at all. Other: Tailwheel is fixed about 30° to the right when you strat on the ground, making taxiing and straight takeoffs almost inpossible. Althought the following are not direct part of operation limits and checklist, could be usefull to know: Blenheim mk IV bombsight problem: If you fly for example at 6000 ft with 190 mph TAS level flight and you give this parameters to the bombsight, it points approx 3 miles closer then the actual impact point. So i adjusted the input settings to find the correct impact point and here are the results: Scenario 1: Adjusting the airspeed with correct altitude to find the correct inpact point: Fligth conditions 3000 ft 190 mph TAS: Set height to 3000 ft set speed to 90 mph Fligth conditions 6000 ft 190 mph TAS: Set height to 6000 ft set speed to 110 mph Scenario 2: Adjusting the altitude with correct airspeed to find the correct inpact point:: Fligth conditions 3000 ft 190 mph TAS: Set speed to 190 mhp TAS the height input is 12000 ft Fligth conditions 6000 ft 190 mph TAS: Set speed to 190 mhp TAS the height input is 16000 ft Also when you set the airspeed you'll see the speed setter wheel turning in the right lower part of the bombing sight. It have a scale from 100-260 I belive it's in mph, but it turns uncorrectly. Althougt the bar/lath in the left upper section of the sight have a scale between 90-310 mph. The wheel turns like this: set with keys / Indicated in the wheel: 90 / 258 100 / 120 110 / 155 120 / 190 130 / 225 140 / 258 And so on in the same pattern, so you can turn it arrond 3 times. I belive it is pretty wierd... The last minor issue I found that when you press shift+F1 to look into the sight it's focusing on the right side bar, which is the "minutes to 60 miles" indicator. I would rather look on the left side bar which is "airspeed in mph x 10" or make it switchable. Also i tried the BR.20s bombsight, which works just like the Blenheim sight, and it's works perfect. Also the He-111s and the Ju-88s bombsights works as they should in my observations. These results were taken in the previous 1.01 patch but seems all are valid in 1.02 aswell (in my observation). |
Answer to climb problem
My squadmate 56RAF_talisman has answered the question on failures on climb out.
The answer is never to go above 4 lbs boost during takeoff and switch to coarse pitch as soon as 120 mph is reached. Once on coarse pitch, keep to about 0 lbs boost. It flies beautifully then. 56RAF_phoenix |
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Many car engines use diverted air warmed by the cooling fins or radiator to provide warmer air for the carb. I suspect that's happening here. 56RAF_phoenix |
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I never got off the ground once (mainly because I have a single throttle and struggle to steer, then overheat one of the engines)! But I can confirm that engine temperature between 200°C and 250°C. Over 250°C and you blow the cylinder head. Certainly, after taxiing, it often pays to sit and let the engines cool to a little above 200°C to give plenty of margin for takeoff. I struggle to believe the heat capacity was so low that the temps would vary that much. If it were that important and variable, the gauges would be in front of the pilot! I also think Mechanist is onto something: Quote:
56RAF_phoenix |
actually, the Blenheims CEM is of that kind i wish EVERY developer would have to fly it for ,lets say, 10 missions (with a groundstart and at least one change from fine to coarse pitch every mission :D ) and for every mission he blews his engines he would get 10% less salary in that month !
perhaps that would let them think again...................... With this being the only british bombcarrier - i dont see good things for any comming online "war" with the BoB scenario . The whole radial's CEM have to be looked in again IMHO. |
okay, so what the freeek am I doing wrong? I can't seem to be able to load bombs (or get them to drop) on this thing -.-
After getting familiar with that diva, spending a few hours to get that big old gasket-blowing thing in the air and fly comfortably, I thought "hay, now let's bomb something". Not. I've done a.. well.. standard load-out in the options/plane menu with red tracers and 4x250lbs bombs (it's over max. takeoff limit then). So I tried, and tried, several times, then scoured the forums and found out that the loadouts are STILL not working in stock quick missions (I did the cross-country one). Okay, next step: FMB. I set up a quick route to bomb the Boulogne harbor, set my loadout done earlier in the plane options, and changed fuel loadout to 90% to bring T/O weight down to below the max. So I flew to Boulogne - I couldn't change fuel loadout in the preflight screens, and everything was greyed out(again) but in the air, I tried my guns, which had red tracers by now. Good sign, but I still couldn't bomb in any way... Could someone please give me a step-by-step checklist to get (droppable) bombs on that thing? That would be great, while we wait for a fix...again. Oh, and what about the bombsight? I figure that (after entering ALT and TAS) you've got to get the target into that little ring mounted on the rails, then drop, right? P.S.: Also, when throttling down to sink before landing, I somehow freeeked my engines.. they didn't rev up properly anymore (when going to fine pitch for landing approach) and delievered no more power, leading to a crash 200m before the landing strip :(. Whats the proper procedure to prevent this? I think the engines got too cool during descent - maybe I should have re-activated carb heaters... P.P.S.: Do I have to switch on the autopilot for my tail-turret gunner? Or is that done automatically and he becomes active when bandits are near? |
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Spending 5 to 10 minutes RAMP start just to see engine failure right after T/O unless you work exactly along a thin red line of procedures really doesn't make you feel like you just played a combat sim turning off the computer. |
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If it were so easy to overheat engines with the rads open while taxiing the RAF would never have got off the ground as a squadron! Plus the manual instruction (in Klem's pdf) wouldn't say to takeoff with rads closed. 56RAF_phoenix |
Redroach - it's good to see a few of us are trying to get this right!
To state the obvious, you are arming the bombs and opening the bombay doors? 56RAF_phoenix |
Gp to FMB
select any map select an blenheim Than selesct the bombloads and save these bombloads as "2x500" and "4x250". Than these bombloads will apear in the armamentchoices in the singlemissions. Keep in mind that the shortcutcommand "release bombs" does not work from bombardierposition, only from pilotposition. From bombardierposition you have to click the small yellowbuttons left on the desk with the mouse ..... You need an open bombdoorcommand shortcut. You will not find a lever in the cockpit because the real blenheims doors were springopened by the weight of its bombs.... You have the choice between salvo (all bombs) and single. The bombsfuzes are alwasy armed. Yo not much to set in comparison to german bombers. Good luck! |
And yes , the gunners are shooting with Ai.
I personaly dont bother anymore with shooting manually...... And online delete all tracer rounds from my gunners, nice surprise for human flown interceptors :D |
ah dummnit... thanks so far, guys! Why didn't I think about the bomb-bay doors? I knew they were bungee-operated in real life, but I've already looked up here and read about the necessity to open b.b.doors.
And thanks for the procedure! Now if you tell me how exactly the bombsight works, I'll write up my personal take-off procedure :D |
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Can't help with the bomb sight I'm afraid.
On another topic, for the first time I took a Blenheim up to 10k ft from parked... it took forever climbing at +2-3 boost and about 400 ft/min. But more seriously, I'm convinced the Blen in CloD has no auto-rich mixture with altitude. When I got to 10k+, I started getting the shakes - just like the Hurri before it was fixed. Also, as I got higher it was harder and harder to maintain engine power and airspeed. 56RAF_phoenix |
to be honest, I don't think the Blen belongs to that altitude... she starts struggling at 7000 feet for me and won't do anymore without carb heat above that :rolleyes:
But if you insist, slap on the heaters and go for auto-lean mixture, that would be my tip... although you're somewhat limited in terms of boost when going lean. Anyways, I think there's still interest in working startup procedures, so here is what works for me: -[OPTIONAL]The Autopilot knows how to lock the wheel brake. Hit it for a few seconds and look for the lever on the steering column until its done... the AP will begin startup procedures instantly, so for max. realism, don't do that -select "Inner" tanks for both tank selectors, located at your 4 o'clock. Above these selectors, there is a 3rd one, which is, I believe, for cross-feeding in case of engine failure. It doesn't hurt (so far) to switch it to 'on'. To get the corresponding tank content displayed, switch the fuel level gauges to 'inner' - on your 8 o'clock high. -pull back on your stick to be able to see the magneto switches. Activate them all. -activate carburetor heaters, located on your 8 o'clock low, right beneath the pilot seat. I just switch them on/off rather than having them on a slider, so for me its 0%-100%. -set mixture to the lower half (pulled towards you) of the quadrant, getting 'auto rich' mixture. See Blackdog's postings in this thread. -set prop pitch to 'fine' - slider all the way up (!) -set radiator full open, just as a precautionary measure -throttle to 5-10% -start left and right engine individually. You may get some mileage from actuating the primer pump, located to the right of the pilot's seat. For me, it's somewhat ambiguous. -if you've got both engines running, wait a minute and do something else in between, like calibrating your gyro. The engines are rather precarious in the first minute or so, so don't choke them. -[OPTIONAL]You may close your radiators in order to get temperatures high faster. However, that's a bit tricky and you shouldn't, under no circumstances, forget to re-open them fully for take off. That WILL kill your engine fast. I just leave them open until at cruising altitude. -switch off carb heaters to get an extra kick for take-off (with them on, engines run a little bit too 'rich') -If the engines run solidly, rev them up to 40% (step on the wheelbrake of course) in order to get oil temperatures up to 40deg. -back to idle/10%, grant the engines a little rest -rev up to around 70% (so that you can still hold the blen with the brakes) and watch the engines going crazy, revving up and down on their own. Wait until you've got stable rpm on both engines. -back to idle/10%, again, a little resting...again, a safety measure -activate the boost cut-out in order to get higher boost for Take-off. This is again somewhat risky as you can blow your gaskets in 30 seconds or less. YMMV. -step off your brake and throttle up for take off. Go full throttle but don't go into the extra-boost region yet. With no airflow over the engines, this will kill them even faster. -once going 60-70mph, I normally go into extra boost. Not the full 9lbs, rather around 7-8 and only very briefly, for about 20-30sec. max. as airflow is still somewhat scarce. -lift off at 80-90mph, raise your gear immediately. Don't pull up immediately, let her build up a little speed, probably for quite a while. Deactivate boost cut-out. -compensate for rudder mis-trim: for me, it's at least 40 clicks 'left' in order to get her flying somewhat straight. -Now, it's your decision: I normally go for coarse pitch quite early, in exchange for extra-bad climbing performance until I picked up some speed. However, you may very well be able to stay a bit longer at fine pitch if you monitor engine temps properly. -switch carb heaters back on. I just feel safer with them. -my cruise settings: around 6000ft, throttle 50-60% auto-lean mix (switching at around 5k ft), coarse pitch, 180-200mph, engine temps arond 220-230deg (don't exceed 250!), rads 1/4 open, carb heat on, well-trimmed to get a good bombing approach. |
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Also the gauges are in perfect spot for the bombardier to keep a close watch on it. Would be nice if a human bombardier could sit back and help out while you're ferrying. Note that the radiator and trimm controls are nearby aswell. As for bombing procedures, my observations are the following: - As mentioned before the bombsight don't work properly, so we have to wait for a fix. - On the other hand if it were operational it will be very tricky to get a decent hit with just 2 or 4 bombs at higher altitudes. I have run some tests on bombs dispersion from 3000 and 6000 feet, and they can impact anywhere between 30 to 300 feet (4 bombs). Basicly the bombsight can only be used to hit a factory site, railway station, port, or an airfield, but it won't be effective if only one blenheim carries out this kind of mission. 9 or 12 would do in vic or diamond formation. - For three or less blenheims (which occurs mostly in online games) the only way to be effective is to use an attack dive bombing in low altitudes. With this way a flight of blenheims can easily take out columns, trains, parking airplanes, bridges, railway stations, ships, encampments, etc. Unluckily performing a percise attack dive takes a lot of practise, because there is no instrumental aid for such attack procedure in the blenheims cockpit. I say you must drop about 1000 bombs to get the hang of it, also if you get the "feeling" when to release the bombs you will able to do it in any other plane aswell. Most of us have this "bombing sence" from il-2 allready and it works fine in CloD too ;) But here are some advice for the beginers: - Always line up on your target if it moves or just longer in one direction, like a train, a ship, or a bride. - Moving targets are best approached from behind, because you decrease the difference of speed between you and your target (easier to hit slower or stationary targets then fast moving ones because you have to calculate an impact point witch is before the target) - The higher angle you have the closer the bomb will impact to your crosshair\sight. That is the whole point of Stuka like dive bombing, but it requires dive brakes which blenheims doesn't have. - The lower you release the bomb the preciser your bomb will impact. Just remember that most bombs have to travel certain time in the air before its armed, and you can damage or kill your self with your own bomb. You can use timed detonators, but I won't reccomend them against moving targets. Although 1 or 2 secs might be fine against slow moving lightly armored targets. - If you have few bombs against a linear-like target wait few milliseconds between releasing them, because you will do more damage against a column or a train, also you improve your direct hit chance on a ship or a bride. - Choose your loadout wisely if you know the exact target you going to destroy. For example two 500 pounders are great for destroying larger buildings, bridges, or ships, but will do less damage against a 20 car long column, then four 250 pounders. Be aware that the blast damage decreases with the square of distance, so if you are going against a linear-like target choose more lighter bombs the few heavier. In the other hand four 250 pounders will do minimum damage against a concrete bunker or a heavily armoured ship because it doesn't have enough penatrating power, so in that case us heavier or penetrator bombs. Germans have SD bombs which don't blast much but will penetrate armoured or thick targets. Thats all I can recall, for now... :) |
hmm now I'm able to bomb - thanks so far. But still, a few wierd things... :rolleyes:
In the video I made to watch, I noted that, when opening the bomb doors, a single bomb fell out just due to opening...?!? I mean, what the freeek? Sabotage? Bad ground crew? One does not know... With the remaining three 250-pounders, I noticed that the bombsight (how I presumably use it) is indeed waaaay off, as was already stated. damnit! Also, could somebody give me a primer (heh) on fuses on the blenny's bombs? What are the differences and which ones should I use, with what delay? Thanks in advance! |
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For bombing you need to map keys to open/close the bomb bay doors first, as well as the salvo selector keys. As for detonators, i use the so called "ever ready" ones because they are always armed and always explode. Take care though if bombing from low altitude, in need to jettison them or you get engaged by fighters and your bomb load gets hit, because these detonators are primed and ready by default and will explode under all these circumstances. The reason you're probably having trouble is a known bug with the bombardier's controls, the bomb release key/stick button only works from the pilot's seat. To drop from the bombardier's seat you need to click on the cockpit switch (the yellow buttons on the small "bench" to the left of the bombsight), so once you're a couple of seconds from dropping zoom out to a wider FoV to bring them into view and click them (the medium one works well as it's a good compromise between viewing the cockpit and being zoomed on the target). For the landing part, i had that happen to me as well and your assumption is partially correct: you did over-cool them but it's not something that can be fixed with carb heat. What you need to do is reduce throttle and bleed off some speed while on approach, enough to drop flaps and gear, then re-apply some power to overcome the drag and trim for your descent. During all this you need to also monitor the cylinder temperature (gauges are on the right-hand cockpit wall, to the pilot's 4 o'clock position) and adjust cowl flaps accordingly. The aim is to prevent yourself from pulling back too much on the throttles and cooling the engines too much, because then they won't produce power. Keep them at 200 degrees minimum to ensure the engines can develop full power, if it drops further close the cowl flaps or apply some throttle while still in the descent, or both, to make it rise back to operating temperature (200-250 degrees). Of course, all this workload necessitates a bit of experience (trial and error mostly but you can get it right in just a couple of tries, i flew some touch and goes to practice) and most of all, giving yourself some time to juggle all these parameters. This means a longer glide path from further away from the airfield and some prior planning of what to do. In other words, it's a full blown approach in the proper sense of the word and not a "cut throttles, bring it in and firewall it briefly for the flare" deal like we could do in IL2. I think the CEM is somewhat masochistic in the radials but i can't help it, i like quirky planes :-P I can't judge how accurate it all is, but when i'm in the mood for a challenge i always select the Blenheim. There are at least a few things that need tweaking (pilot's manual from back in the day says "do this" but it doesn't work in the sim), but overall i think it will be one of my favorite aircraft once we get a few gameplay-related fixes in a subsequent patch. I think the main issue in terms of CEM is how certain parameters affect the temperatures. It's realistic that the radials are more susceptible to temperature changes, but what might be off somewhat is how these temperatures change. For example, warm up takes so long that we can close the cowl flaps, step on the brakes and apply throttle to accelerate it. However, for start-up, warm up and taxi the pilot's operating handbook recommends open cowl flaps because the temps rise too fast when on the ground. I think this is an issue of environmental modeling and it's also noticeable on the liquid cooled fighters, it's just that their engines handle better over a wider part of their allowable temp range. My theory is that it's part of the dynamic weather module which is still under development: ambient temperature and heat build-up from idling on some hot tarmac doesn't have as much of an effect as it had in real life (according to the pilot manuals at least). On the contrary, the manual recommends closing the cowl flaps for take-off! The reasoning is that once the aircraft is finally moving, there is enough airflow through the cowlings to maintain acceptable temps for the small amount of time that take-off power is used. In the sim it's reversed, we need full open cowl flaps. I've done some observing and it seems this is true for other aircraft too (Spits were notorious for overheating on the ground if idling somewhat high, but it doesn't happen in the sim), but it's more noticeable in radials because they are temperamental and can't develop power if not at the correct temperature range. It seems both the effects of airflow on cooling during flight and of lack of airflow on overheating while on the ground could be bumped up a notch. However, the pilot's manual also categorically states that cowl flaps should be opened as soon as the pilot has configured the aircraft for climb. This means pulling the throttles back to 5 psi boost and also switching to coarse pitch as soon as the aircraft picks up some speed. I've climbed on coarse pitch, it's not hard and it goes at a pretty good pace too as long as you follow the observation you added in one of your later posts: the pilot's manual recommends staying level after take off and not climbing straight-away. This builds up some speed and once you hit 120 mph or so, you immediately switch to coarse pitch. This not only results in more speed (which if left untrimmed will result in a climb, so you just trim the elevators and rudders a bit and let it climb), it also lowers the RPM and prevents heat build-up somewhat. Climb gently until you hit 150mph, then you can properly climb. I'm sorry for holding back (hey, it's summer :cool: ), i should just bite the bullet and finally copy the relevant parts of the pilot's handbook here during the coming days. Ironically enough, it might have "cost" me more typing answering set-piece questions than having copied the manual right from the start :grin: |
yeah, some parameters in the Blen's FM are definately off... however, she's certainly flyable.
climbing with coarse pitch works just fine, but only if you've picked up some speed before. If you try to climb with coarse and 90mph, you'll have trouble staying aloft. |
Well, 90 is way too low. Minimum safety speed (in case of engine failure and so on) is 120 mph. It's a bomber after all ;-)
Climbing speeds are 150 mph up to 10000ft, reduced by 10mph every 5000ft after that: 150 mph until 10k ft 140 mph between 10-15k ft 130mph between 15-20k ft The fact that the manual doesn't specify altitudes greater than 20k ft tells me it's generally inadvisable to fly higher than that :-P I guess it makes sense, keeping in mind a) the RAF's preference for low level bombing tactics, they must have some reason behind it (lack of engine power? also point b below) b) the fact that the bombsight has crude adjustment intervals for speed and altitude, that thing looks mighty inaccurate and according to another poster on this thread who tested it, there's a lot of dispersion and not enough bombs to effectively drop from higher altitudes. I think i'll just bite the bullet and start copying the pilot's handbook tomorrow, it will save us all some trouble getting this thing to fly properly (me too, since i'll probably learn it better in the process) :grin: |
so... nothing new about the bomb not properly fixed by ground crew? :D
P.S.: Has anyone noticed that the blenheim has a rather beautiful sound in external view? :rolleyes: |
Okay, I've been searching the web for a) how to use the bombsight properly, and b) more info on the different fuzes. Sadly, I came up with almost nothing so far :(
One thing I did find, however, was some pics about the blen's bombsight: http://users.cyberone.com.au/clardo/..._armament.html The sight is identified as a Mk IX course-setting bomb sight and the drawing suggests that there is more to adjust than I currently do (just alt and speed, while considering the sight being off, as mentioned above). Apparently, you have to look at the junction between those two rings. A thorough explanation would be greatly appreciated! As for the fuzes... the search has been frustrating. I've found heaps of pictures from collector's sites, but no info as to how they work. A short table would be greatly appreciated as well! |
Interesting findings about the LSC and SBC. It would be definitely usefull to have them in the sim. 16 40lb bombs would be just like the AO-10 in Il-2.
WWII allied fuses are quite simple, mostly mechanical. Ever ready fuses are working like a nail. If you push them on one side it will put presure on the detonator charge which leads to a chain reaction known as explosion of the bomb. The more common mechanical fuses are armed by time with a spinner which is spinned by the airflow. When the spinner reaches its final position the bomb become armed an will expolde on contact. You can put a timer mechanism in the above mentiond constuction, which will count down from the moment of inpact the a pin will put presure on the detonator charge. Most of (if not any) the fuses have a safety pin which blocks all above mentioned actions. Usually it is removed by the falling of the bomb, Imagine a pin in a slot (in the fuse) which is tied to the releasing mechanism on the plane. Here is a schematic of a very primitive mechanical fuse for aerial bombs http://img.tfd.com/ggse/b9/gsed_0001_0005_0_img0783.png |
Bit more info on sight here
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Every little bit helps ! Have a read of this about halfway down the page! http://www.twinbeech.com/norden_bombsight.htm |
wow, nice pictures. Thank you! Though the workings are still somewhat shrouded in mystery ;)
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Supercharger
In general the two crucial things are to keep below 4lbs boost on takeoff and switch to coarse pitch ASAP.
[EDIT] I should have read Redroach's exellent post on the page above before sounding off. I'l have to try the inner tanks when back from hols. I've been up to 11k ft climbing on 3lbs boost but there's no second stage to any supercharger and the mix seems bad, just like the hurri used to be. Frankly it needs work. 56RAF_phoenix |
I presume the bomb-drop on doors open is the way of simulating the gravity operated doors?
Such a shame we don't seem to be able to move behind the bombardier's compass for the run-in to target! 56RAF_phoenix |
Still looking for advanced infos on the blenheim bombsight (Mk IX course-setting bombsight) and on the fuzes, so consider this a shameless bump! ;)
Besides that, the "one bomb just falls out on opening the bomb bay doors" - issue still bugs me. I should have a serious word with my ground crew. :rolleyes: The explanation phoenix gave to that just adds to my confusion ;) P.S.: Addendum to my T/O procedure above: Now that I've got the drill of getting the Blenheim into the air down, I've become somewhat more cautious with using the boost cut-out for add. manifold pressure on take-off. If you've got a well-built runway, like that one where the blen's spawn on syndicate, it's very possible to take off without engaging the boost cut-out. As mentioned, it's really, really easy to blow your engines with that, so just skip that step for additional safety. Just don't forget to disengage carburetor heaters after your engines run smoothly; re-engage them if you go above 5500ft. P.P.S.: I'm really scared of sparking another 'octane war', but.. has somebody tested if boost c/o operation is safer when feeding from the outer tanks (which, presumably, are filled with 100oct. fuel)? I haven't yet tested that, but maybe someone has... I see a certain possibility that this is indeed the case |
i am also VERY VERY carefully when starting a Blenheim on a DogfightMP map.
Using fine pitch i seldom use seldom more than 2300rpm - having always a quick look at the temp gauges. I am far away from using 110% throttle with fine pitch , therefor i dont activate the "boost cut, out". I even try to roll in start position with enginetemps below 200°. To get a longer save time to run the engines at 'higher' rpms during the actual startrun. And than after going to course pitch i am wondering why the possible rpm numbers are so high in the instruments :D , so low they are. sidenotes: -i have no proplem with "one bomb is falling when opening the bombdoors". It does not happen with my settings. -you dont have to activate magnetos manually (in any CoD plane!), they are activated automaticly as soon you hit "I". |
for how to properly use the fuses, I finally stumbled on the A.O.Checklist (how could I miss that all the time? sigh):
http://forum.1cpublishing.eu/showthread.php?t=24547 But still, more info is needed on how to properly use the blen's MkIX C.S. bombsight... another bump :D |
I'm having a rough time keeping the temps within limits.
Either the oil gets too cool or the engine temp too hot. There's no margins for error. Any tip would be appreciated. I found the tip of quickly turn on/off autopilot to lock tailwheel a tremendous help while warming up. According to Blackdog and Fleas manual I should take off with rads closed but that doesn't work for me. Overheat before tailwheel lifts. |
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You have to start with open cowlingflaps. I personally start with flaps down (unfortunatly you can set them only between full out and in :( ) and tray to keep the engine rpm between 2200&2300......not much, i know, but so i am at 90% of my starts on the save side. Sa alread said, this plane needs a second look from 1C, even more important as it is the only RAF bombcarrier in game. |
real manuals do help, in general, but in this case the blen's FM is quite a bit off in terms of engine temps. Leave the coolers open until safely in the air and your engine temps start to drop.
And, in my experience, there is no such thing as "the oil gets too cold". Shortly after T/O, I set prop pitch to coarse, engage carb heaters at 5500 ft - with these actions, my oil temps were fine all the time. My "engage AP for a second" referred to the wheel brakes, btw. Are you sure that the tailwheel gets locked, too? |
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Could you confirm this... - Open rads lowers engine temps (and vice versa)? - Activated carb heaters raise engine temps (and vice versa)? - Throttling up i.e. higher rpm raise engine temps (and vice versa)? How does coarse pitch affect the temps? I mean, lower rpm gives lower temp but coarse pitch give higher load on engine. Quote:
Thanks! |
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Maximum takeoff power to 1000ft, 3 minutes limit: with 87 octane fuel: +5 boost 2650 RPM <- i dont tested these rpms, but my wild guess would be, in CoD you would coke the engines very fast......... in general the given rpms in the manual are much higher than i ever fly (or can reach in coarse) in the game. But again, true, they are numbers for a CPS Mercury - not the twospeed one of the M.IV. |
you even quoted the part which counts...
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I always end up postponing this, but i see a lot of people have many questions.
I finally decided to bite the bullet and do it, these are the most important bits as a quick and dirty reference ;) So, without further ado, here are the Blenheim MK.IV operating limits and abbreviated checklists, according to the proper Mk.IV pilot's operating handbook: Take-off:
Climb:
Cruise:
Diving:
Landing:
Missed Approach and Go-around:
After landing:
Engine Limits:
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The above post is now also supplied on the initial page of the thread for ease of reference.
@ 2GFlea: If you want to incorporate this into your PDF checklists you are welcome to do so. |
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It just showes that a historical manual is not always helpfull to fly the CoD Blenheim. :)
Thx for the summary Blackdog !! |
Ok, I can take off and cruise no problem. But I'm concerned about the small margins when I take off.
I've read here that some of you take off when CHT is around 200. If I do that I'll overheat so I let CHT drop to 180 and then decidedly push throttle to max for +5 psi. At 80mph I quickly rotate and retract gear and ease down throttle to 60%ish and dip nose to gain speed to cool engine. If I pause there and check CHT it's very very close to 240. I run the cross-country mission so no bombs but full tank. Any tip on how I can keep CHT down at take off? Edit: Btw, is the only way to load bombs to use FMB or online? Edit 2: One thing that struck me that I gonna try right now is to slowly increase throttle so I keep temprise minimal while gaining speed. Brb. |
flying the Blenheim
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I can honestly say that the Blenheim is the most rewarding aircraft to fly, It is not very forgiving but can take massive amounts of damage and still make it home on one engine as long as you have 10000 feet under your wings ant treat her well.
We frequently do 2 hour round trips in to La Have or the Rouen Boss from Sandown and make it home. The following is how we do it! Spawn Aircraft with 85% fuel. Switch on magnetos 1&2. Switch on wing tanks 1 & 2. Switch on Boost cut off (just in case). Drop your throttle to 11%. Select and Start engine 1. Select and Start engine 2. Synchronize both engines. Adjust your course setter to the north position. Adjust your directional gyro to the heading you have just obtained from your course setter. Trim your rudder to the neutral position. Trim you elevators to just under the neutral position. Open up radiators to the fully open position. Increase throttle to 35% and you will start rolling out, once moving drop you pitch down to 90% and taxi to the run way (use you pitch controls to keep you water temp on or just above 200, the 12 o clock position on your dials). Stop at the start of the runway and let your water temp drop to 200 (12 o clock position on your dials). Then increase throttle to 50% reset pitch to 100% and keep a straight line by using your brakes until your tail lifts. As soon as you are airborne retract undercarriage and reset you elevator trim. Reset elevator trim to make the aircraft climb at about a 25 degree angle and drop pitch to 90% and switch off boost. The Blenheim should fly all day like this but keep this in mind: Keep the water temp just over 200 degrees just past the 12 o clock position on your dials, use your pitch and radiator controls to do this as you get higher it gets colder you need less radiator and as your climb rate decreases you need less pitch. You can push her up to around 70% throttle but damage will occur sooner or later. When you get to 6000 feet turn on your carburetted heaters and this will settle your RPM down. The thing to keep in mind is that every time you adjust a control there is a consequence for it, heat for water or oil, speed, height whatever. So when you move something you have to change something else. By the time you get to your cruising altitude and trim the aircraft to fly level you should find that the radiator is almost closed the pitch is around 40% and the fuel mix can be dropped down to about 75% too, and you can get around 140 to 170 MPH if you get it right. The bottom line is never take your eyes off dials it only take seconds to stuff an engine. Hope this helps |
Due to the small disparities between sim and the manual for the real aircraft, that's what i usually do:
1) Set mixture to rich, prop to fine, open cowl flaps and start up. Sometimes carb heat might be needed, but remember to turn it off after starting as it can rob you of power at low altitudes. Also trim full left rudder. 2) Close cowl flaps to accelerate warm-up, step on the brakes and throttle up in steps: as soon as the gauges start bouncing around due to engine vibration (which indicates engines running rough) i stop advancing throttles and let the temps catch up, once it's warmed up a bit more and the shaking stops rinse and repeat. 3) When you reach 180-200 degrees CHT open cowl flaps, advance the throttle to obtain between 0 and +1 psi boost (about 60%) and start rolling down the runway. 4) As soon as you start picking up some speed your rudder will be effective in controlling the yawing motion caused by the props, so either adjust trim or use manual rudder inputs while advancing throttle the rest of the way. I think we don't need that much fuel for the current map. One famous wartime raid involved an attack on the Cologne powerplants, that's the kind of distances these tanks were used for but we don't have that big a map yet. Better to fly only on the inboard tanks and save up some weight, especially since it will translate to a shorter take-off roll and a faster transition into actual flight, where the overheating dangers are mitigated due to the increased airflow at higher speeds. The inboard tanks are 140 gallons each (280 in total), the outboard ones are 94 gallons each (188 total). The full fuel load is thus 280+188=468 gallons. To get the fuel percentage we need we can simply divide the gallons in the inboard tanks to the total: 280/468=0.598 So, setting fuel to about 60% should do it. I don't know if the sim will split it evenly across all tanks though but it's a small issue if it does: we might need to change over from one set of tanks to the other but other than that we'll be still flying with the correct fuel load. I think that adding a more detailed interface for fuel in place of that slider (similar to the one we got for bombs and guns) at some point would be awesome: imagine having complete control over the contents of individual tanks, both in terms of quantity and in terms of octanes. Well, that's one for a future patch, for now just set fuel to 60% and fly ;-) |
Thanks for the tips Blackdog. So far I've managed one successful mission with the Blenheim on the Syndicate server but sometimes I still get caught out when starting up either waiting too long for the engines to get warm or not waiting enough. :P
Taking the fuel down to 60% might help get it moving a bit quicker on the ground for a take-off. :) |
Seems that 50-60% throttle is what most of you use for successfully take off without overheating.
Gonna try that tonite. xpupx, good tip on using pitch to keep CHT within margins while taxing. Will try that. |
You have only tow pitchsettings, coarse and fine. Just move your pitchcontrol from 100 to 0% when the engines are still off and watch the propellerblades......
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That's what i initially found out and it's confirmed by the manual for the real aircraft, the Mk.IV had a propeller system similar to the DH hurricane and the early Mk.I Spit we have in the sim with only fine and coarse positions. In the sim however it's possible to move the pitch sliders gradually but only the fully back position switches to coarse and anything above that switches to fine.
On the other hand some people say that while the animation is that of a two-stage prop, it actually works like a fully variable one. I think we need to do some more testing to clarify this. Xpupx's write up is still good advice though, minus a small inaccuracy: there is no water temp on Blenheim. The engines are air cooled so the gauges display cylinder head temperature ;-) Other than that it's pretty sound advice, especially the part about how each engine control affects certain parameters. I still do some things differently but it doesn't mean it's the only way. For example i don't keep the carb heaters on unless i'm flying close to clouds, because heating the air lowers its density. This means that the mixture is also altered (less air volume for a given fuel volume, it's like running a richer mixture) and i don't know if the semi-automatic mixture systems corrects that. What i've found out is that you can easily fly up to 10000ft without any carb heat at all. I just turn it on along with the pitot heater when i get fog/icing on my windshield, then turn it off once i'm out of the layer of humidity. Now, i don't know how close this is to reality, but the current Blenheim in the sim can fly fine with reduced or no carb-heat usage when in clear skies, getting a bit more performance in exchange for having to keep an eye out for potential icing effects. It's easier to just set carb heat at a certain alt and leave it there but you'll get a bit reduced performance, so it's up to us to individually decide on how to do it. However, in the real one they probably left the carb heaters on so i guess i should start doing it like xpupx does :-P The mk.IV manual has no recommended settings about carb heat, but the Mk.V manual does. Since the engines are the same (the main difference is that the Mk.V has constant speed props while the Mk.IV has two-pitch props), maybe we can follow the same guidelines. Here's what it says: 1) Warm intake should be used: a) For all flying at less than +3.5 psi boost, unless atmospheric temperature is more than +15 degrees Celsius. In that case (more than +15 C), Cold intake should be used regardless of boost. b) For all flying (regardless of boost used and ambient temperatures), when in conditions of high humidity, in or just below clouds, in rain, snow or sleet. Warm intake can also be used to help warm-up the engines in very cold weather. 2) Cold intake should be used for all other conditions, including: a) Starting at all times b) Take-off c) Landing, unless the bad weather conditions of 1b) apply. So, i guess it's safe to turn it on and keep it there at the altitude where the ambient temp drops below 15 C. Since we don't yet have the dynamic weather, i guess the sim uses a standard atmosphere model. In that model, the ambient temp on sea level is considered to be 15 C and drops 6.5C for every 1km of altitude (or roughly 3000ft). In other words, if CoD uses an ISA atmosphere and the carb heaters on our Blenheim are similar to the Mk.V carb heaters, we can turn on carb heat as soon as we have completed takeoff, assuming we climb at less than +3.5psi boost. I usually set it to +1 boost for a normal cruise climb, so it would definitely apply to my method. The easiest way to see what kind of ambient temps the game uses is to spawn a Blenheim in the cross country mission in the QMB without starting the engines, accelerate time for a while to let the engines and oil get up to ambient temperature and see what kind of temps the instruments indicate. I think that last time i checked this CHT temps were 10-12 C, so it definitely looks safe to turn on carb heat as soon as you climb 500-1000ft after take-off and settle into reduced power settings. |
On atmosphere model - if there's a landing strip on a higher alt then one could check ambient temps at sea level then fly (or fix it in FMB) to the strip at higher alt and let the engine cool down. :-D
Then we'd see if there's a change in temps at diff alt at all. I could do that but I dunno where to check for alt (I never set that on the alt meter). Btw, anyone checked if temps changes over the course of the day? That should be simple. Gonna check right now actually. Brb. Ok, back now. Ran for almost an hour. In game time (tod) was from 09.00 to 23.00. I checked Oil temp and CHT. No change what so ever at anytime during the test. A bit funny is that all temps showed different - oiltemp port 17, oiltemp starbord 14, CHT port 10 and CHT starbord 12. I see this as an indication that there's no atmosphere model at all except for clouds. |
Tried with 60% throttle now and that did the trick for me.
Not much runway left but who cares. :-D It's fun handling the Blenheim but when I read about it on Wikipedia it is depressing how little damage they did and the high number of casualties they sustained. |
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Prop pitch seems to be two stage in the 3D modell. (on 0 pitch input it turns right to a more featherd position, on anything else than 0 it turns left to its takeoff position. You can observe it when the engines are stoped) However, it have a full effect on rpm in different positions (not just two stages) as I measured: Throttle 75 % IAS 200-210 mhp Height 8000ft Radiator 100% Carburetor heat 100% Pitch % / RPM 100 / 2660 75 / 2520 50 / 2320 25 / 2120 0 / 1760 My findings about the carburetor heat Carburetor heat seems to work inversely. In 100% you'll get less engine temperature then in 0% Throttle 50 % Pitch 75% IAS: 150-160 mph Height: 8000 ft Radiator 100 % Carburetor heat % / Engine temperature °C / RPM 100 / 201 / 2260 75 / 203 / 2290 50 / 208 / 2340 25 / 221 / 2380 0 / 233 / 2480 Also the carburetor heat controll lever labeld as "AIR INTAKE SHUTTER" (Don't really know how it suppose to work on this airplane) Also mixture doesen't work at all. Just try a mission with mixture at 0%, then refly the same mission with 100% an you won't notice any difference at all, regardless the altitude. |
Interesting findings, maybe we can use a bit reduced pitch to prevent overheating then until they correct the propellers and the airflow/overheat modeling.
As for the mixture, it's semi-automatic (just like in the Spitfire) and that's why we can't see a difference: 0%-50% mixture is auto-rich, 51%-100% mixture is auto-lean. It will automatically maintain either of the two ratios depending on where it's set at, so moving it back and forth doesn't produce any rough running of the engines. I know you will wonder why does the lever move gradually, instead of "snapping" into the two extreme positions like in the Spitfire, but for some weird reason it was like this in the real aircraft: full range of motion for the levers but only two effective settings. |
So in short mixture is inverted and carbheat is inverted and the animation of the prop is that of a two-stage prop but works like a fully variable one.
Did they get anything right? :-P |
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Carbheat works fine for me. Has anyone climbed over 11k ft without engine shake? 56RAF_phoenix |
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56RAF_phoenix |
I think there is a bit of atmospheric modeling included, it's just static for now for each altitude band. Temps do tend to drop with altitude, but sitting on the tarmac on the same field (or flying a constant altitude with constant power settings) will give a steady temperature.
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Shaking above 10k ft
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Increasing it too far reduces power, so increase it until the shaking stops and add a couple of notches. 56RAF_phoenix |
I am so impressed that you guys are prepared to spend so much time and effort in trying to understand this quirky tempramental unforgiving unreliable awkward old bird.
If only the devs had spent half the time and dedication you guys have on flight testing this aircraft, then maybe we would have had something that would have been worth flying. Perhaps better still they should have spent the time making the wellington a flyable model. This "harder is better" mentality that infests CloD is very frustrating. I do like extra complexity and am perfectly happy messing with rads, oilcoolers, carb heat, prop pitch and boost, but I cannot abide engines that overheat just trying to taxi TO the runway, prop pitch and mix levers not properly modelled and all the other depressing little faults that keep coming to light. Please answer me this question honestly guys. Has ANYONE taken off from England fully loaded arrived over target and bombed on target in the face off flak and enemy aircraft and got back home landed safe with full real settings CEM ? Personally I cant hit a target smaller than say Calais or even perhaps Paris and the thought of a Me110 being within 50km of me is rather daunting to say the least. |
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One additional drawback, though: On syndicate, you take off from Littlestone and your parking position is fairly close to the runway. So I didn't bother taxiing and pushed the throttle forward from the parking position, ending up on the runway at 40-50mph. If I had taxied, I'd look at an additional wait time of 3 minutes plus just to cool the engines again in order to avoid blowing them on subsequent takeoff. So yeah, the temperature models on the blenheim are pretty much crap. But this is CoD :D P.S.: Oh, and I bombed an empty airfield... :rolleyes: |
i was once over St.Omer looking for the ordered target to bomb at 11.000ft on the ATAG server. i was unable to spot a target , so i decided to attack ships again.
That is what i do with the blenheim online - sinking ships with 500lb bombs with skipbombing. and a penny for every time i look on the cylindertemp gauges during a mission............. :D oh, i forgott, last time i hunted a squadron of AI Ju 87s attacking my landing area, i could not realy catch (110% throttle and coarse pitch) them :D |
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Took a bit of coaxing and trimming after the initial evasive maneuvers and loss of speed so i was left a bit behind, but i still managed to catch up to the rest of the flight mid-channel and made a no fuss landing. Two things to keep in mind: 1) Don't use more than 60% fuel, you don't need it. (60% is about the limit of the inboard tanks, plus a bit on the outboard ones). 2) The Mk.V's pilot's handbook (which uses the same engines) advises carb heat usage above a a few thousand feet (it's in the checklists i posted). They said they are reworking some of the physics for the next patch, so maybe the taxi will become easier. What usually happens with heavier aircraft is that they need an initial burst of power to start rolling, but after that it's easy to keep them going while almost on idle, maybe we'll get a similar ground handling correction in the FM. |
Well, with the Air Traffic Control (aka the family) still away on holiday... I tried some skip bombing off line with the Mission Builder.
I was horrified to find that the AI could fly on settings I can't dream of. As soon as I switched the autopilot off, gaskets blew, cylinder heads blew etc. The AI flight model seems miles away from what we can do. Disappointed. 56RAF_phoenix |
The AI flies a different engine model, this had been announced ages ago during the development of the sim.
This is done for performance reasons: enabling CEM costs as much as 10 FPS on some PCs and that's just the player's aircraft. Imagine what would happen if every AI aircraft had full CEM and on top of that, needed an AI smart enough to use it. We'd be limited to 4vs4 dogfights or less :-P The way it works is that instead of having the AI conform to all the limitations of CEM (and having to use up even more processing power to have an AI that can work with these), they just give them a set of artificially imposed limits so that they simply don't "cheat". In other words, the AI only knows what is a reasonable speed to fly and flies that speed. It won't operate cowl flaps and manage temperatures and operating limits in the same way a real/human pilot will, because it would bring any PC to its knees. |
Some very good news with the latest beta patch.
First of all, the revised ground handling physics make it much easier both to taxi and to takeoff with the Blenheim. There is still a tendency to yaw to the right but nothing like before where we had to use differential braking to keep it going straight, which killed our speed, prolonged the take-off run and could kill our engines through prolonged full throttle use. Now it needs less braking, which lets it pick up speed and get in the air faster, in turn allowing us to reduce power before those gaskets start leaking. Second, the new sounds make it easy to identify if something's wrong with the engines because there are some new sound effects for when they are running rough. This makes it easy to adjust power settings and cowl flaps without having to constantly keep an eye on the gauges, once you hear it running rough you take a look at the gauges, take corrective action and that's that. This means that you can now give it about +1.5 boost and once it starts rolling down the runway you might need a couple of taps on the brake with the rudder full left to realign with the runway centerline, but after that you have enough rudder authority due to the airflow to keep it straight simply by stepping on the rudder. At that point you can advance throttles the rest of the way. I did it today in the cross country QMB mission (the one with the crosswind and small runway) and i had a heavy fuel load and four 250lb bombs in the bay. Third, the bombsight now works. According to the patch notes it also has an angle of attack adjustment but it's not manual like in real life, you just have to fly smooth for a little while. In any case, the altitude can now be adjusted in increments of 100 feet instead of 1000 feet that we had pre-patch. By the way, there is a magnetic compass with a course setter on the base of the bombsight too and it's much easier to use that to calibrate your directional gyro: you can see enough of the horizon from the glass nose to keep the aircraft level (more than you can see from the pilot's seat that's for sure) and you also have a clear, unobstructed view of the compass. You align the red north marker with the end of the magnetic indicator (there's an arrow on it that points north), then press the relevant keybindings that you've set for the DG to calibrate it. It's also very useful for navigating, just set the course setter to the heading you want to fly and turn until they match. Also, moving the course setter in one of the cockpits (pilot or bombardier seat) moves it in the other cockpit too. So, i started the allied free flight mission loaded with four 250lb bombs and set a heading to Calais, while leveling off at 8000ft. Using about +1 psi boost to keep within the lean mixture limits gave me about 180mph IAS. By the way after a bit of testing while taxiing on the ground, i think that the carb heaters are indeed reversed as reported by others in this thread (set a key to toggle them all the way so the change is instantaneous, you can then tell when it's on because boost drops slightly when carb heat is engaged). So, keep that in mind while flying higher than 3500ft or so, or near clouds, or just listen for the engines. I trimmed for a more or less hands-off flight while crossing the channel (it still needs corrective inputs from time to time but not much) and settled in my bomb run. For aiming, i used the conversion tables from the manual and extrapolated from there. It says that at 8000ft a speed of 200mph IAS equals 225mph TAS. I was doing 180mph, that's 20mph less IAS so i reduced the TAS value specified in the manual by a similar amount and set it to 200mph. Coming up on the target i simply flew the plane with gradual banking turns through the bombardier's position, keeping an eye on my altitude and airspeed indicators on the bombardier's panel and adjusting elevator trim as necessary, just a notch or two at a time. Once i was lined up and closing, i switched to bombsight view, selected my salvo and arming options, opened the bomb bay doors and took aim. I think the stock mission has some wind because my bombs drifted to the left a bit, but i did hit the target (an airfield just west of Calais). It was great fun and the slight inaccuracy makes it all the more enjoyable: there is a bit of bomb drift but not too much and it's definitely possible to carpet bomb a target with a couple of wingmen, it's just enough to give you a bit of welcome suspense ;-) In short, our cranky little bomber is now a real joy to fly and bomb with, dealing with the 109s and 110s is another matter though ;-) |
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