Aircraft peformances, is this joke ?
 

Hi,

I've been testing today the performance of our actually modelled Spitfire IIa, and compared to the figures of the book written by Jerffrey Quill, a test pilot throughout the WWII, who kindly tells us his story, and we can find also graphics and key figures.

Not only is out aircraft, in CoD, not modelled accurately, but also the vertical speed dial indicator is about useless as too inaccurate.

I have measured, in a constant speed climb (160 mph IAS) and full climb 2850 rpm, full throttle boost 6 1/4 (no boost cutout).

The climb dial shows a value higher than the calculated vs, but its error depends upon altitude, it varies 20% error at sea level to more at high altitude.

The expected performances of the Spitfire MK I were by the book 285 mph at SL and 360 mph at 17000 ft.
In the game, we have 268 mph at SL and 320 mph at 17000 ft (IAS 243 and TAS 320 I estimated a standard temperature).

That's a false vertical speed indication (I expect the altimeter hopefully works fine)
and that's about 17 mph at SL and 40 mph at rated altitude less than the MK I
as performed by IL2's Mark IIa which was equipped with about 15% more HP.

Finally, to answer to a question from Blacksix about accuracy of the Mig performance due to the fact that it has much less performances that German aircrafts, question related to balance of the forces
I would like to answer, first please let us have aircraft accurately modelled in terms of performance, and we'll let you know later on if this is a real issue online when we effectively into action.

Edit
Performances expected on Spit I (Merlin II / Merlin III engine) and Spit II (Merlin XII) are by those above figures with +6 psi boost.
The 'military power' +12 psi enables more than respectiveky 1030 and 1175 bhp and hence are would allow an extra speed over 285 SL and 360 @ 17000ft.

I dont know if you are using the latest beta patch but if you pull the overboost knob you can then push the throttle over its normal distance and therefore you can use emergency boost.

Right

If you truly wish to have improvements made, please register with Bugtrackers and vote accordingly. Otherwise your justifiable concerns will go unheeded by those who decide: the MG devs.

http://www.il2bugtracker.com/issues/370

It's now in ID 394

personally i doubt if there going to make them exactly the same
for example
the manual of the BF-109E says that the plane is a heavy tail so during take off you have to push your stick fully forward and to the right....do that in COD and soon you will be dead very soon
the plane it seems very unstable
and the rudder it sucks;)

B6 statet that they are aware that there are issues with FM left. It´s WIP.

Wow, that was quick!

Voted.

http://www.il2bugtracker.com/issues/394

Agree, they have to get it about ok, would be enough. I also read the spitfire had a very particular way of spinning, it did it quite eratically, however that was in the very early stage of its development (by 1938 ) and I'm not sure how it went off later.

All in all, it is said that for the time, it was a very good airplane (the Spitfire).

Why would Ilya release betas if they're not interested in our findings? The FM's have been a WIP for several betas and the devs clearly don't test them in house, otherwise they would be correct by now.

agreed

But this would be very strange. If something is not influenced by different systems, then it is the flight-model.

If they want us to test the flightmodels alone, i can't understand why. I am sure they have easier ways to test them (graphs, datas form the game, etc.) than we have. So it wouldn't make sense at all to let us do the testing...

Yes, that is the way is should be, no question. However, the Flight Models have repeatedly been wrong with each retail and beta release, so clearly this is not the case.

I am confident that IvanK supplied the devs with the correct Flight Model data, as Ilya has gratefully acknowledged in this forum. However, not only did Ilya choose not to implement this FM data in the public release back in March, 2011....he has chosen to diverge further from the correct Flight Model data further and further with each successive retail and beta release.

Prior to the second-to-last 1.06 beta release, Ilya released through Black Six some selected RAF FM charts that were clearly incorrect, yet despite a collective outcry from this 1C community he opted to implement them anyway. At the time, those of us that voiced our concerns were told by other members of this forum "to stop complaining; it's a WIP -- the beta hadn't been released yet, so how do you know it will be wrong?" As if we can't read a flawed chart. True to form, beta (alpha?) was released -- it was a disaster. A "Hotfix" was quicky issued which made it a launchable disaster.

Now we have beta 1.07. Hurricanes don't start. Spitfire Mark I's don't start. Go to 12 lbs boost and you get less-than-87 octane performance for less than 2 minutes before the engine blows -- and remember to go to Full Lean Mixture while you do it. Ilya released this nonsense??? No mention in the beta readme notes. Oops.....no readme notes.

This is why I fully support anyone such as the OP who takes the trouble to do the testing that the devs SHOULD be doing -- while the rest of the 1C "community" sit on the sidelines at snipe at the effort.

English is fried in the online, that is the result, the balance went from "red heavy" to "blue heavy" (understand red's too light performance)

I claim it should attach to what was at the time for this is realistic sim.

I'm not a pro "sides shall be balaced". That's why team work is there, it can do the difference, it really does I can attest.

But most ppl dont give a crap about it.
I'm no different, no even in real live.
(delegation is a different story tho) :)

I hope they fix the service ceiling of all planes rather than tinker with just one sides FM. Both sides cannot reach their ceiling limits.

Agree, Doc. Both sides' aircraft need fixing which should've been done long ago.

Was looking at Mig-3 and 109F, not that much different, I think it's going to be interesting flights if the models are right (battle of Moscow).

BTW did you mean you were selfish person ? Or maybe I just misunderstood.
I meant sometimes it does'nt matter wether the aircraft you're in is not so good if you've got a good wingman (or leader) ... sometimes.

I really need to learn to make myself clear.

Still waiting on a proper Emil as well.
Sadly this has all already been said. Many, many times.

+1

also... are you switching to rich mixture at sea level ????

i can get 290 mph out of the spit 2a at sea level with boost cut off enabled and rich mixture just as it should be

Shiver me timbers! I'm a staunch and obsessive "do-it-like-the-real-thing" guy, but if this were EVER implemented, we'd probably not be able to stem the wave of complaints rushing in. It scares me to death right now!

Yep. And when you do that, pull your mixture lever back to Full Lean and see what happens.

oh, and: Isn't Lean <==> Rich in the current (latest) beta incarnation? At least on the SpitMkIa?

(I mean that I am of the opinion that the lever works the wrong way around)

Hi Redroach,

Yeah, that's been so since Cliffs of Dover was first launched and never corrected:

http://www.il2bugtracker.com/issues/18

But that's not what I'm referring to in my reply to Looksharp.

No I don't think it was this way, the engine is rated with its full boost of 6,25 psi, going over that should give you an extra margin on top of the normal performance.

That's what I have understood from the sources I could cross.

Also if you note that the military power was only to be used for short time, I don't think it was the meaning to level the aircraft and apply more than its rated power in order to determine its maximum speed. You have to take into account that it was leveling up for a relatively long time before a stable reading could be obtained, say between 5 and 10 minutes most probably.

If you find informations supporting that it shall have its performance with the boost cutout open and applying the full available boost, I think it'd be worth to share.

In my opinion, we should have the right performance without use of bost cutout, up to my understanding. Octane grade 100 was probably also not available in 1938 for the Mk I prototype. The prototype itself fit with a wooden fixed pitch propeller reached 349 mph TAS at 17'000 ft.

I'll try to get more accurate datas from one of the big books I have related to Spitfire, a very good and complete one indeed. Those are interesting lecture.

Edit
I find no information supporting that the max speed of Mk I & II were measured with more than the rated power at 6 psi of boost.
Apparently the Mk I had 1030 bhp at altitude (either 16,250 or 17,000 ft ?) and Mk II 1150 bhp at 14'500 ft, source "The story of the spitfire" book.

Generally speaking, all piston aircraft checklists that i've seen specify rich mixture for high power settings.

The engine runs a bit more powerful on auto-lean but it also runs quite hotter, so for all high power regimes of flight auto-rich is used. Lean is just for cruising at reduced fuel consumption.

In short, going flat out and switching from rich to lean might cook the engine in short order.

I was lucky enough to have access to a friend's PC with a quite a few FSX add-ons that do extensive engine management and that's where i practiced before CoD was released.

At some point we were flying a Catalina add-on by Aerosoft that is modeled after the one they have restored in the Lelystad airfield museum in the Netherlands. We even did a 10-hour flight in it across the Caribbean, taking turns at the controls.
What we noticed right away was that flying at economy settings on auto-lean would result at the same cylinder head temperatures as when flying at higher power on auto-rich. The lower demands on the engines were completely offset by the leaner mixture.

The main gain was that we were burning less fuel because of running the engines at lower manifold pressure/RPM. Going to maximum continuous power resulted in the exact same cruising speed (an abysmal 100 knot IAS, that's slower than many cars :-P ), but we had to go to auto-rich mixture instead. Then, after 2-3 minutes we also had to open the cowl flaps fully and the result was that at max continuous power we had to compromise so much in drag that our speed was lower and our fuel consumption much worse.

So why don't people fly like that (on lean/economy) all day long? Because higher power means better acceleration and climb. The difference here is that we were just cruising, but in a combat scenario it's different.

You can also see this in CoD to an extent. There are times when i am cruising at 1.1 Ata and the 109 does 380km/h IAS, there are other times when i'm pushing emergency power and it barely does 350km/h because i just exited a maneuver.

What we need is someone who can extract the data files to tell us which way for the in-game controls and levers corresponds to lean and which to rich for all of the flyable RAF aircraft, so that we can deduce with some accuracy if and what is wrong.

Leannig purpose to keep air fuel mixture to 1/15, when climbing, the less dense air means it comes to 1 of fuel for less than 15 of air in ratio, in other words, too rich of fuel, so less efficiency, some fuel is burnt meanlessly.

However as explained there's a temperature issue, generally, when the leaning is done manually, full power with rich mixture expect at very high altitude where some leaning may be needed.

When cruising one can lean further.

Except if the sim has a sort of bug, no full power should be done with lean but if one wants to shorten an engine's life. Maybe they'll model an engine failure due to incorrect leaning.

Obiously, a lot of fuel consumption reduction achieved at altitude in lean mixture, could be 20% less. I seem to remember the spit was giving 40 gph rich and 35 gph lean by 15'000 ft.

Per Redroach's post above, the Spitfires have the mixture control incorrectly reversed in Cliffs of Dover. The Hurricanes have the mixture control modelled correctly: Pull backwards for Rich, push forward (toward the instrument panel) for Lean. When CoD was first released last year, a lot of Merlins got destroyed over this confusion until it got sorted out. Surprisingly, this seemingly easy fix was never rectified so newcomers are still frying Merlins as a result.

To confuse the issue further, when flying a Spitfire IIa at low level you go "through the gate" with your throttle and hit 12 lbs of boost at 3000 rpm with your lever in Rich position your aircraft begins to shake, throwing your aim off. Pull the mixture lever back to lean and your aircraft smooths right out -- until it blows a head gasket after about 2 minutes (on a good day).

So, you have a choice at 12 lbs boost, 3000 rpm low level in a IIa: strong shaking (rich mixture) for 2 minutes before you kill your engine, or silky smooth (lean mixture) for two minutes before you kill your engine. Or push your WEP button for 1.33 ata repeatedly with no ill effects at all for a whole tankful of gas. Oops - sorry, the Spits and Hurries don't have that feature.....

I would call that glitching. Should be instant kick on a server. :-P

I can add some more to this, the figure that is usually quoted for a MK I Spitfire is 362mph at 18,500. This was referring to K9787, the first production Spitfire, in 1938.
Between then and the BoB there were some substantial modifications that lowered the top speed. A 73 lb armoured plate, bullet proof windscreen, 3mm of light alloy covering for the top of the upper fuel tank, installation of the IFF etc..

The AUW of K9787 was 5,819 lb, the AUW of a BoB period Mk I was around 6,115 lb.

There were also aerodynamic penalties, the IFF aerial was reckoned to cost 2 mph, the windscreen cost upto 6 mph. The top speed of a fully equipped Spitfire in Battle of Britian trim was closer to 350 mph at the same altitude.

Sources - Spitfire The History and Alfred Prices Spitfire in Combat

Ha!

In fairness, the same can be said for those dastardly Red pilots that fly with canopies open (ie. "sonar") to listen for those 109 pilots sneaking up from behind. None of whom continuously use their WEP buttons, of course! ;)

What about those 109 pilots that jettison their canopies to get an even standing (or simply open their side windows)? <: )

A plague on all of us!!!! LOL

My ultimate wish for Cliffs of Dover? That Ilya would approach IvanK with the sole wish of resolving the FM issues once and for all for EVERY a/c, including bombers. IvanK would be free to pick whomever he wanted from this community to assist -- but he has Final Say. Ilya could send IvanK periodic (ie. FREQUENT) betas dealing with FM adjustments only...along with readme files (a nice thing to have)....with adjustments based on IvanK's input on the prior FM Betas. Once IvanK signs off on the final FM Beta, then that's it. Done. IvanK is given a nice Morris roadster for his trouble, and we can then move on to quibble about hedgerows vs tree-lined lanes after that.

Or how much the tachometer needle should jitter......(uh oh, shouldn't have said that.....:rolleyes:)

Wish it was so easy. You know this community. Whatever numbers the gents from Maddox Games put in here, there will always be somebody with a chart trying to prove them wrong, does not matter blue or red or pink or whatever.

That has such a long history that I don't know what to believe anymore anyways and just fly the damn things as they.

Ain't that the truth!

The reason I specified IvanK is because I believe his judgement would be respected by both sides. They may not agree with certain aspects, but he certainly represents himself as even-handed and knowledgeable with both LW and RAF aircraft. As it stands now, the devs seem incapable or unwilling to apply hard data into credible Flight Models. Witness the ongoing RAF fighter debacle that has gotten progressively worse with each CoD iteration, per my earlier post. Certainly both LW and RAF aircraft need serious FM overhauls, including fighters of either side that can actually exceed 30,000 feet!

As it stands now, it would appear that the devs cannot deliver aircraft that either side can accept in terms of FM's, unless they enlist and heed someone such as IvanK to put things right.

It "could" work this way. Clearly lots of stuff has to be revised. I think one major problem with altitudes, however, is the lack of propper high altitude atmospheric modelling. I remember a post by Luthier stating that this will come with the sequel.

Funny, they will implement it with a low level combat scenario.
That said, imho, everything making airplanes work in the first place should be fixed with priority.

Does not make much sense to have a propper speeding Spitfire when the Bombers can't level bomb due to Lofte issues to begin with. A Me109 with real life climb speed won't be much of an achiecement if the Hurricane can't even get it's engine started.

Too many basics have to be fixed first before going into fine tuning. But that is just my personal stance.

This is right

Prototype K5054 1050 bhp at 16'000 ft at 3000 rpm 6 1/4 psi boost reached nearly 350 mph.

Merlin II engine was 1050 bhp at 6.25 psi boost (octane 87) and 1300 hp at 12 psi boost (octane 100) but shortening lifetime by a factor of 10 (100 hours to 10 hours).

-------------
Mk I

Martlesham Heath, 6 january 1939. K9787. Merlin II performance trials.
Cruising 318 mph @ 15'000 ft
Max spd 362 mph @ 18'500 ft
6.5 min to 15'000 ft (2300 fpm mean)
22.4 min to 30'000 ft

-------------
Mk I
May 1939
295 mph @ 1'000 ft
276 mph @ 20'000 ft
(I assume this is IAS)
-------------
Mk II

Spitfire serial K9788 was tested with merlin XII (the Mk II engine) with following results :

Boost 7 lb 366 mph @ 18,900 feet
Boost 9lb 369 mph @ 16,700 feet
Boost 12 lb 372 mph @ 13,450 feet

What you say is correct, with the only difference that the RAF fighters have auto-lean and auto-rich mixture. The Hurricane seems to be manual in the sim but it should be the same as the Spitfire, maybe it's just an animation error on the lever and it is in fact only two settings?

In any case, here's the short version from wikipedia:
http://en.wikipedia.org/wiki/File:Id...ichiometry.jpg

According to that graph the best air/fuel analogy for rich is 12.6:1 and for lean 15.4:1.
What the semi-automatic mixture controls do is they try to maintain these ratios, the pilot only selects if he wants rich or lean.

It is very clear however from the graph that there should be a difference in power and fuel consumption, just like you say ;)

So, the Spit mixture controls are currently modeled like US and general aviation designs (rich is forward)? Good to know, because i thought that lean is forward and i was wondering why it's easier to start on "lean". :-P

Yep I was'nt entering into details because I was'nt sure if it was fit with auto rich/lean.
Thank you.

15.4:1 at full power / boost would melt the pistons in seconds

egt would be too high plus would det itself to bits.

14.7 is storch ( best air/fuel ratio ) but only for none charged engines or cruising .

12.6 is a very good AFR for a forced induction engine and with a bit of water methanol to cool the charge for the extra boost ;)

Its all these issues combined with a non existent flight manual is why i rarely fly CloD.. i simply don't know what the hell the correct way to do something is and if i do think i know it does not work in game.. leading to much annoyance & frustration.

The lack of flight manual is simply shocking.. when i've complained in the past i've been accused of being lazy, and the info is on the web. To me that is not acceptable, CloD is the 1st of the IL2 series I've really flown.. and it will be the last due to the lack of quality that MG have applied to it in regards to documentation and info.

My flight manual for my DCS P51 is hundreds of pages, and covers everything , the section covering each plane in Clod is about 2 pages and generally worthless.

I would just love to know how something is meant to work in the sim/game and have it work like that and it clearly documented so i can understand it. Then i could enjoy this game.

DCS P51 includes exactly "1" plane. Imagine you have to do the research, the writing and the editing not for only one, but a good dozen aircraft. Not to take away from your critique, I agree that aircraft should have much better documentation. But then again Things change so quickly in this Sim that what you read today may be untrue tomorrow, so any documentation would have to be constantly updated.

As much as I wish for that, I can't see that happening currently, especially given the financial abilities of Maddox Games.

On the other hand, it is not that hard to learn to fly the fighters here propperly. If lack of documentation holds you off, you can always come here and ask. If you think that is too much of an effort for a Sim that should have worked from the start, well, you will be in great company by some of the more vocal members here, but I doubt it will be a satisfiying expirience.

When in doubt, just go to the ATAG servers, get on Teamspeak and most people will be very helpful in giving advise or explainations.

jf1981,

That link (and in fact this whole argument about performance) have been debated ad inifnitum on these forums for months. There are those who quibble with the data on that page, so simply dropping the link doe not, unfortunately, really provide any impetus in any particular direction...

Of course EGT will only rise to the optimum Fuel air ratio and then start to decrease.

Google "lean of peak" and you will find quite a lot of arguments and discussions of the befits of "Lean of peak" opperation for enhanced fuel efficiency

Of cource this is all moot since the spitfire used an automatic mixture control and the pilot had limited control over the fuel air mixture. "Lean of peak" is more applicable to more modern airplaned with computer controlled direct fuel injection, ignition and engine monitoring.

I appreciate the difference.. and don't expect all the planes in CloD to be documented to the same level as the P51 in DCS.. but there is a compromise. And actually if you include Flaming Cliffs2 & DCS they have about 12 airframes..all very thoroughly documented. (Su 27/33, Mig 29/29a, F15c, A10a/c, Su25/25T, Ka-50, P51 off the top of my head)

I love detailed sims.. and am not sly of putting in the effort of learning and reading... but this in CloD has been a frustrating experience.

But i appreciate you advice on how best to learn this sim.

Good points.
For the moment, and thanks to a dedicated few, the community is doings its best to fill in the knowledge gaps, in some cases almost back engineering the FMs to try and get some idea of how the A/C perform. For the moment, his forum and the people on it are our best resource.

.
One point to make;

This is a GAME!

Have fun .

I'm conducting flight trials and will pursue that task, and report my findings, feed the bug thread.
And I'm relying on several specialized books available regarding the Spitfire.

The actual flight model is a nonsense.

I have to remind you that's I'm not debating anything.
The devs can do whatever goes through their mind. But I have to say how wrong this is, if it indeed is.
Note that I'm also working on the good side of that game when I can like tutorials, mission building.

I tested other parameters of Spit Mk I

- Stall speed is too low by approximately 15 mph flaps up, by 10 mph flaps down
- Take off run is longer by approximately 30%

Thought the take off run is not a so big deal, it shows that the reacceleration from medium and low speed time is longer, the performance is not as good as it shall be.

The stall speed, on the opposite, makes for better turns at low speed. It makes the gap between radius of turn of Bf 109 and spit wider than it should be.

you are not right. The Spitfire is has a very realistic FM. This is the best flight sim ever !

try the spitfire from A2A with accusim
you will suprised by the differences

Hey jf1981

You might want to hook up with klem and others who have been doing some testing.. In that what I have found over the years is most of the so called FM errors turn out to be pilot errors and or a misunderstanding of the test methods and or conditions. Not to mention all the little aspects of the simulated world that can have an effect on the results. For example something as little as the atmospheric conditions of the simulated world/map v.s. the standard atmosphere conditions that most if not all real world data is presented in. The following thread is a good example of which I speak..

http://forum.1cpublishing.eu/showthr...t=33077&page=5

With that said, if you really want to get serious about testing the FM than you have to get serious about collecting test data during your test flights. Here is a link to the C# script file that klem and others are using as a baseline for collecting test data during test flights.

http://forum.1cpublishing.eu/showthread.php?t=27552

Note it saves the data to a standard csv file format that you can use EXCEL or OpenOffice (which is free) to graph and compare the data.

I highly recommend you use this script during your flight tests! Because if you don't, when you make a claim, for example such an such is approximately 30% off, there will always be doubt as to if this error was due to pilot error or an error in the FM. By collecting (logging) the test data during the test flight you will not only be able to remove the word 'approximately' from your statements but also reduce if not remove any doubt as that the error was due to pilot error.

:lol:......This is laughable yobnaf,how would you know this is very realistic,have you actually flown the MK2 Spit in real life,have you actual experience of the Mk2 Spit?

I very much doubt it,yes the COD FM is a good representation of this aircraft,but please,give us a break!....honestly there's too many guys on here getting carried away with their own importance,it's a bloody flight sim for Christ's sake!:rolleyes:

I was as accurate as I could. Thanks for your links, we're really doing retro enginerring by now ....

Talking about performance. The FM's indeed very good, but now the unbalance completely unfair. The spit had much better performances, I get that from many different sources which I do not detail here. Books and websites. Have a look.

Of which I had no doubt..

We all try to be perfect, but the fact of the mater is we are only human.

By collecting the test data during the test flight others will be able to review your test flight to see NOT only how accurate the FM is but how accurate your test method is.

No problem if you have any questions, feel free to ask! But looking at FST's post he explains it step by step on how to use the C# script

Enh.. not really.

But the more standard we can make the testing of the FM the more useful the feedback we can provide to 1C

I used a method accurate enough for that purpose, the margin for error in terms of vertical speed and top speed is really a matter of few percents. Agree it can be nearly zero with a better method.

By retro engineering I mean flight testing in order to determine what was set inside the code.

By the way, could you have a look at the vertical speed dials ? I looked at the Mk II spit and got nonsense values, if you could check with you method, It would be interesting. I determined about 30% error low sea level and a 200% at 18'000 ft (the VSI higher by factor of 1.3 to 2 from SL to alt).

Aircraft IAS looks right versus map scale and time checks. Altimeter can only be assumed to give correct reading, I see no obvious way to cross check.

What figures are you using as your real life ones?

The only reason I ask is that the usual figures for Mk I/II come from aircraft that were quite a bit lighter than BoB trim aircraft.

Any idea what the AUW is for your RL numbers?

(delegation is a different story tho) lol

Winny,

"Spitfire, A Test Pilot's Story" from Jeffrey Quill
"Sigh for a Merlin, Testing the Spitfire" from Alex Henshaw
"The Story of the Spitfire, An operational and combat story" from Ken Delve
"Spitfire, The history" from Eric B. Morgan & Edward Shacklady

All being very good lectures.

Just out of curiosity do these references give consistent data (same or similar performace) for any of the given Spit variants?

JD
AKA_MattE

Maybe.. maybe not.

Hard to tell for sure without the test data

The only way to make such a claim is to collect the test flight data and calculate the error..

Which I am sure you did by looking at the guage, writing down the value, than calculating the error after the test was done.

But taking 'a' value at 'a' point and doing 'a' calculation can have a lot of error associated with it..

Where as if you collect all the data, you can see trends, spikes, ect due to pilot, test flight, method, etc errors.. Whch can be taken into account when processing the data.

That and you can compare one data ponit to another.

For example, take ISA and Altitude.

I have seen a lot of people in the past (IL-2) do a top-speed-test and claim that a speed is too slow or too fast.. Because they were watching the ISA, wrote down a value, than looked at the altitude guage and wrote down a value.. All the while doing so not realising they were not flying all that level anymore.

But when I played back the track file and logged the data I could see that the plane was in a slight climb (not flying level, altitude changing), at the point the pilot said it was too slow, or, the plane was in a slight dive (not flying level, altitude changing), at the point the pilot said it was too fast.

Little errors like that can result in making false claims of FM errors!

The best way to ensure that does not happen is to collect the data while your flying, than you can focus on flyng and look at the data afer the test (post processing).

On that note, we could do that during or even after the test with IL-2

Because the track file contained all the test data that could be extracted using DeviceLink.

But with CoD, there is no DeviceLink

So you have to collect the data as you are flying (real time) using the C# script file

Agreed nearly

But never zero

With that said, at this point, we can not tell if the errors you say you are 'seeing' are due to an errors in the FM or an error in your test (method or piloting).

I know

Which is why I said 'Enh.. not really'

In that testing is not retro/reverse engineering

It is testing! ;)

Not at the moment..

I am busy with my own testing, that and I have to finish the C# that I promised I would do for klem

It would be best if you spend a half hour or so reading FST's post and using his C# to collect data and checking it for yourself.

That way we are all on the same sheet of music (a testing standard) and can work together and share data.

Too bad you didn't collect the flight test data during that flight so others could review your calculation to see if they obtained the same error values..

Looks right..

Not the most scientific method IMHO..

Better to collect the test flight data during the test flight so you can 'measure' just how right ISA is

No need to 'assume' if you collect the test data during the test flight

And you never will until you start using the C# script file

Yes I can assure I'm writing down in flight the datas, it's getting all right and thought I do not post everything, it's all available on my strips of paper.

When I do speed trials I maintain height within 50 ft, and doing climb test, I maintain best IAS within 5 mph. I record time and height with max 1s error.

That's for the tests I've made up to now. All in all it's minor error, but if really needed, I can post flight test datas and error estimation, but I guess, it's not so far away from the true figures.

Maybe.. maybe not

Hard to tell without the test flight data

Mk I expected about IAS 290 SL and 280 18 kft with a boost of 6 1/4.
Apparently Mk II had rated boost of 9 lb/sqin ?
109E is also under rated.