Spit IIA Speed in game test
 

Attached graphic is my Speed test in CLOD current version + Hot fix.
Blue Line my results, Broken line Spit I spec, full line Spit II spec

METHOD
Each run commenced on altitude with stabilised Oil/Rad temps Oil Temp at 80deg C. Rad Full open (At present I cannot detect any Rad drag so radiator position is not relevant imo)
Each altitude was a specific FMB set up. Altitude maintained +-50ft throughout the test. QNH checked as 992mb on the specific map used.
Each run done 3 times and Vmax average plotted.
Seal level temp estimated 19 deg C based on HEIII OAT gauge on the same map on the ground. TAS calculation based on standard 2 deg C lapse rate from the surface. so at 16,000ft I was using an OAT of -13deg C
My test wt 114lbs less as reported by FMB than the spec wt

Power setting was Full throttle 3000RPM. Indicated Boost +6. Now its important to understand that displayed Boost is not I believe actually measured in the FM but represents an angular animation value. We all know that it should be indicating +9 in the Spit II.

I gave up testing at 17,000ft as things were radically different from the spec values.

Results plotted as accurately as I could.

http://i40.photobucket.com/albums/e2...iIIClodspd.jpg
If someone wants to convert the test values to Standard day figures ... go for it.

A note about the test method. I think it would be possible to get the top speed by measuring the movement of the aircraft over the ground by a mission script.

About the test result. It just makes me sad but to be honest it doesn't surprise me at all. Could you do 2 reference values with "emergency boost" at see level and one at FTH?
Out of curiosity, was there are large difference between the 3 test runs?

there was very little diff on each run in the order of +- 2Mph max IAS as far as I could interpolate on the ASI. Each run was flown like a precision Instrument Flying exercise.... actually better than the +-50ft tolerance I quoted.

I will do some runs as requested with Boost cutout as well. Same for the Hurricane test which I have just posted as well.

Distance covered over the ground would provide Ground Speed. Working back to get TAS might be an issue as we really dont know the atmospheric model. I know the QNH is accurate but the base Sea level temperature is based on OAT with a static observation of the OAT gauge. In other tests at various altitudes in climb and descent (I was trying to map the lapse rates used in the CLOD atmosphere) I was getting some very strange OAT values ... to the point I gave up.

Same Basic Mission.

Spit IIA Sea Level Boost Cutout activated 3000RPM Boost indicates Full scale deflection I achieved 285IAS/287TAS

At 15,000ft which is the CLOD +6.25 FTH (with RAM) with boost Cutout activated Boost remained at +6.25Lbs I achieved 258IAS/328TAS

Dropping down to 12,000feet which is where with Boost Cut out the Boost starts to drop from Full scale deflection (+ 8 ) I achieved 267IAS/323 TAS ... same as with out Boost cutout.

Concur.

My test scores (post patch) from previous thread:

Spit IIa

FTH = 13500 ft (?!)
at 6.25psi, 2750rpm (rad open) engine fails after about 3 mins

260mph IAS@13500 = 328mph TAS = 528 kmh TAS

Pretty much exactly as yours for 14000 ft. Except your engine seems to stay a bit cooler and my merlin a bit more fragile:)

For what its worth I did some quick tests on max speed in the Spitfire MkII, collecting data through a BlackBox script and converted them to standard day TAS's The results may not be perfect but they are close enough to show the Spitfire MkII appears to be just below the A&AEE tests of 1940 which is where IvanK puts it too.

I'm not an aviation expert but google was my friend so if the following is wrong well, just say so.

I took the CoD MkII I.A.S. as 'good' and equal to Calibrated Airspeed CAS (assumed no position errors etc). I held ROC as near zero as possible but its a b*tch to trim on my rotary but I took representative data from a consecutive set of near-zero ROC data. I ran with Rad open at max boost and max rpm (scripted out as 2990-2992) although the A&AEE tests used 2850 and I never achieved their 8.8 boost although it did creep up with altitude. The Altimeter can only be set in whole millibars so can't be set accurately (about 15ft out at SL, 430ft at 10,000) but I used it because the pressure altitude calculation uses the mb set in the Alltimeter. I got the true height from Script but did not use it so that's a point of contention.
I took formulae from here:-
http://williams.best.vwh.net/avform.htm#Mach
and...
I used TAS = CAS/(1-6.8755856*10^-6 * D_Alt)^2.127940
... where D_Alt is Density Altitude for <36,089.24ft)
I used Density altitude (D_Alt) = P_Alt +(StdTemp0/.0019812)*(1-(StdTemp0/OAT)^0.2349690)
... where StdTemp is 273.15K, OAT is scripted out Temperature (290k dropping to 270k) and P_Alt is Pressure Altitude = Indicated_Alt+145442.2*(1- (alt_set/1013.25)^0.190261)
... and alt_set was 995mb which is the nearest I can set it for the true height of Tangmere airfield (39.1ft True from script vs 25.46 indicated. I happen to know Tangmere is about 12.5m/39ft.)

Don't be fogged by 'science', if I got it wrong just say so, otherwise here's the chart showing CoD Spitfire MkII TAS vs A&AEE MkI and MkII data for a standard day.

And this is the 'best' fighter in the RAF too.

I too noticed the FTH was way lower than IRL for all types. I also find that the climb rate are particularly inaccurate, once you get over 16kft you'll struggle for 500fpm in the Hurricane. In the Spitfire I find it ironic that it is supposed to outperform the 109 @ 6000m now (20kft) BUT the climb rate above 16kft is so bad that getting there takes forever. I don't think it's an optimum altitude for the Spitfire in game anyway, it's just that the 109 fails by even more @ that alt.

It beggars belief that a company that set out to build a combat flight sim has no idea about the performance and operation of the aircraft they are supposed to be simulating, and appears to have no database of data of their own on which to model it all, instead relying on being shouted at by their own customers. To cap it all there is a databse of bugs, formally raised and set up by dedicated customers which they do know about, but I have little faith that they've paid any attention to.

I run a squadron of about 30+ pilots, we get barely any even turning up now. What do I do?

I've also found a pronounced difference in FM for the Spitfire IIa between offline and online. The two FM's are the same at SL, but I found the IIa's online FM takes a remarkable departure from the offline FM as altitude increases.

Hello Ivank!

I made some tests for the 109 until 4000m (1.3 ATA and around 2280 RPM, rads open). I do not tried the Spits because i am not used to it. I am assuming an error in speed of +-10Km/H and in altitude of 50 meters. The following results:

100m/sea level: 410 km/h IAS
1000m: 420 Km/H IAS
2000m: 430 Km/H IAS
3000m: 430 Km/H IAS
4000m: 410 Km/H IAS

This matches very well your speed found for the spit. Should be interesting gather data from diferent pilots when calculating the average since it one had a different flying hability. After i ll test the 109 for higher altitude. I suggest you create a method of testing and put it here. Then all pilots can contribute making tests following the method and send info to be gathered. This way we can use many observations and reduce the error and the same time no one had big work repeating the tests. And i guess it is much better and informative gather data from different guys.

My guessing is that this guys stating that 109 can outfly the Spit easily in CloD is simply because they are flying wrong, most of time they are simply whirlwinding down there in the deck. I barely can see a spit above 4000m. The want to zip zap when engaged by a 109 with energy advantage then climb like a rocket on its sixs and shot them down. Obviously a 109 coming out of dive will outclimb. The acs aremb them easily very well matched.

You doing it wrong. At 100m's I get 460 Km/H IAS at 1.3 Ata and at 5km's I get 420 Km/H at 1.3 Ata...

I have tracks if you want them.

No need for tracks from you, Farber, AFAIC. As with IvanK, if you say it is, then it is.

Thats going in my sig...

It appears a little pessimistic.

Ballparking it off the data you gave I get your Density Altitude at 14000 feet as ~15500 ft.

It looks like the FTH then is ~1000 feet low and the aircraft is about 3% off in SL Vmax.

Snapper, try adjusting the Altimeter barometric setting in both cases at the same field until it reads zero feet or as near as you can get. Is it the same baro setting in each case or are you seeing different atmospheric conditions?

In my own created server and in ATAG I find the correct setting 'on line' for Tangmere (which is about 39feet) is 995mb. Based on that I set 995 at Manston and get 140 feet in both servers. IOn off-line single mission Free Flight over England after landing Manston I have to set 996 to get 140 feet. So different types of 'day' perhaps?

Maybe that's it, Klem.

Except, the Ia's FM's agree very closely under the exact same test conditions offline vs online. The IIa's FM's do not.

Me and my wingman often have 200m's defference staring from the same field on our altimeters.

3% off in SL Vmax?

((267 mph TAS actual - 287 mph TAS spec) x 100)/(287 mph TAS spec) = -7%

or am I doing this wrong?

??!!

Both have same baro setting?
Reading from the tooltip or the gauge needle?
Tooltips are to nearest 100 feet in RAF planes so one a/c at 90 feet and one at 105 feet will read 0 and 100 respectively.

Or the 109s are porked and next time I will run from a 109 at 25 feet and see what happens behind me :)

We both take off and he'll say 2000m's and Ill say what? we are are at 2200. Read from the needle.

Easiest way to set accurate QNH is set the Altimeter to the field elevation. Field elevation can be found in FMB. Attached file has every airfield's elevation in the Sim all obtained from FMB.

A 1mb error should only result in 30ft/10m error.

I do believe the default maps have some diurnal variation in both Temperature and pressure. I too have seen 992mb as the setting on ATAG at some times and 995mb at other times.

I would like the tracks not because i do not believe But because i would like to learn... Its possible to maintain 460 km/h when coming out of dive but when accelerating in level flight i cannot build more than 430.

Exccellent graph Klem

Specsavers?

Seriously, that's weird. Even if he had set field elevation, typically 995mb, thats only about 150 feet/50m difference from the default 1000mb. 992 would be about 240ft/80m.

YES and pretty much invalidates the ability to test any kind of performance without a stable atmospheric model.

It should be easy to confirm the atmospheric model.

1. Go to a known airport like London Biggen Hill. The field elevation at EGKB is 599 ft.

2. Set your altimeter to field elevation (599 ft) and your altimeter setting should read 992mb when converted. If it does not read the setting and record the temperature.

I get the same figures, ie 460kph in level flight(no diving into it), more with boost.
Trim is your friend, and keep the ball centered.

Temperature is if course important. btw Biggin alt may vary according to spawn point. On my server its true height (pos.z) is 180.77m/593.1 feet at the runway intersections and at the central 'airfield' symbol position in FMB but is listed as 587 feet in the info IvanK posted from the FMB.

In the ATAG server I find 992Mb is almost correct on the safe side but I've never seen Biggin in use on the patched server.

In my Channel test map for my own server I get Tangmere scripted out as 45 feet and temperature 16.9 deg C. Atimeter setting of 996mb gives altimeter reading of 59.08 feet and 995mb gives 31.36 feet (altimeter figures actually captured by scripting but gauge reading is correct as far as the human eye can tell).

At Manston it is scripted out as 150.2 feet and 16.7 degrees C. Alt setting of 996 gives altimeter reading of 167.24 feet and 995mb gives 139.74.

So, on that mission map I would set 995 to give me a safety margin for very low flying.

Now between airfield, a 0.2 degree C change over 145.2 feet altitude change = 1.377 deg C per 1000 feet. Standard rate is ~1.98 degrees C / 1000 ft but my only usng 1 decimal place for temp and a non-standard day pressure could be the cause of that anomaly as, say, 16.949 (Tangmere 16.9) minus 16.551 (Manston 16.6) would take us to 2.74 degrees / 1000. The real figure is somewhere in between so very likely 1.98.

My point is that I'm guessing the atmosphere across the map is consistent and without weather pattern although why it would be different in my server (Multiplayer, Server, Create Server) and the ATAG server I can't say UNLESS ATAG's Mission Parameters aren't standard (does Flow affect this?). I did try different mission start times to see if there is a generic 'day' weather pattern operating changing temperature and pressure over time but the temperature and required baro settings didn't alter between 7 a.m., 12 noon and 9:00 pm.

OK, just some more spare time rambling to indicate we don't have a standard day and we don't know why it changes between servers. Or why Farber's wingman's altimeter reads different to his by 200m :(

I have been asked for the mission and script files I used for my tests. I'm attaching them plus a version of the output .csv file saved into Excel where I summarised some records for the chart and added a few calculations plus some conversion factors and odd formula memos at the top. If you want to save your output as excel then just copy/paste any .csv file data into it. The mission punches up some data on screen and even more data in the output file. Coders can play with he .cs file and add or change whatever they like.

First, how to use the files. Drop the .mis and .cs files into your /1C Soft club/il-2 sturmovik cliffs of dover/Missions/ folder where it is esy to find when you later run Multiplayer.... Server... and create the server ("OK")

Open the Performance.cs file with notepad and search for //FILEPATH
1. Set the filename for output file by editing the part in quotation marks
strfile = "Performance";
e.g. you can see that I have used the name of this mission (Performance.mis) and script file (Performance.cs) without the .mis or .cs extension. The name of the aircraft you test will be added automatically to the filename thus creating separate files for each aircraft tested,
e.g. Performance-SpitfireMkIIa.csv

2. Edit the output file path to your choice by editing in the following the first part in quotation marks (not the "-" or ".CSV" part)
fstring = "E:/CoD_data/BlackBox_Data/" + strfile + "-" + cur_ac.ToString() + ".CSV";

Be sure to create the folders you need in Explorer or the file output will fail!
Also be sure to close the .csv file before you run further tests or the mission cannot write ti the file.

Typical result for the above is a .csv file as follows:
"E:/CoD_data/BlackBox_Data/Performance-SpitfireIIa.CSV"

If you create your own mission you can still use the script. Just copy it and give it exactly the same name as your mission file, e.g.
MyMission.mis needs file MyMission.cs
Don't forget to edit the filename as 1. above to, say "MyMission" to get you MyMission-SpitfireMkIIa.csv

More about the script and output:-

Deep breath and one piece at a time....

The .cs file is a bit untidy with various rem'd out lines I didn't use in the end. Also it comes with a bit of advice...

The whole thing comes from data inside the game, the various C# 'References' parameters. You don't really need to go there but note the following.......

I could not make head or tail of the parameters Z_VelocityIAS or Z_VelocityTAS which I output as WIAS and WTAS. I took these to be IAS and TAS values from within the game parameters but they don't make sense. If anyone can shed any light, fine, but I didn't use these and I calculated the TAS, see below. I left them in the file in case anyone knows them.


G_z is from Z_Overload and is in fact what we would call G value plus 1, so instead I took G values from: parameter part.ParameterTypes.Z_Overload, n
where n is for fore and aft or left and right or up and down. In the output file these are titled Acc_for_aft, Acc_lft_rgt, Acc_up_down (the G value used to measure G-cutout). For those that want to know....
Acc_for_aft = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 0);
Acc_lft_rgt = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 1);
Acc_up_down = cur_Plane.getParameter(part.ParameterTypes.Z_Overl oad, 2);
All most of you need to know is that Acc_up_down is the vertical G value I used to measure G-cutout in another similar test setup.

Ht_m and Ht_ft are calculated from the parameter pos.z and taken as the True altitude. This is the target value when you want to set the Altimeter accurately.

TrueROCms and TrueROCfpm was my attempt to cross check the ROC gauge reading by calculating movement from positional shift but that didn't work out. I was too lazy to remove it. Ignore these.

I think everything else is self-explanatory.

So Finally, how did I create the chart? Well my flying wasn't too sharp as I couldn't easily trim the Spitfire (IMHO its an unrealistic b*tch to be frank) so I had to filter out that mass of data to where the height was the required height +/- 50 feet and the tightest range of Rate of Climb, on one set as high as about +/- 30 fpm (I have left the filter set up for the sea level figures at 0 - 50 feet). Then I looked for a decent set of consecutive records that indicated reasonably consistent flying and took one of those records as data for the chart. These were in any case good within a couple of mph. You'll see I have copied those to the bottom of the spreadsheet. I also added calculations for True Airspeed based on formulae in my earlier post and highlighted in green at the top of the Excel sheet (along with some other junk). For this I had to assume the cockpit indicator IAS value was correct (I scripted it out as IAS). This is because I couldn't find a TAS parameter inside the game.

Thankyou.

PM me you email address and I will send you the tracks. ;)

Or you can try 09:30 pitch and 1.3 Ata, line up the slip slide with rudder (ball - move towards it) and aileron (needle), make sure you are not ascending or decending with the altimeter. You wont be able to go straight to 09:30 pitch you will have to work the pitch down to it keeping the U/pm in the 1900 to 2350 range. Practice Practice Practice!

That is actually realistic. Welcome to neutral stability!

:)

I tried it as well and found it extremely difficult to hold at a consistant climb speed. That is neutral stability and why the aircraft is a two fingered airplane. The airplane required very little trim input to achieve a trimmed condition as a result. Unfortunately, it harder to do that with a computer joystick as we don't have the "feel" of the airplane.

What I thought was unrealistic is the oil temperature rise. I could not get the Spitfire to decrease oil temps satisfactorily.

My oil temps stayed around ~85C in level flight at cruise settings with the radiator fully open and very quickly ran up against the maximum of 90C in a climb.

Running that close to redline in level flight is a squawk and it would be investigated to be fixed.

Granted it is summer time but with the exception of taxing, the temps in the summer never get that close redline at cruise settings.

I really think this the biggest issue. We have inconsistant evidence of atmospheric modeling. Temperature is above standard and pressure below standard. That is consistant and our density altitude should be high as per summer conditions.

What is not consistant is the variation in elevation as I assume pressure on the 200 meter altitmeter readings and most disturbing is the FTH is not consistant with a higher density altitude.

If the FTH matches standard day data by occuring at the same standard day altitude, the Flight Model's reaction to the atmospheric model is porked.

The temps mean I run full radiator open at all times in both spitfire and hurricane. I hope it is fixed for the release of the new patch that adds more radiator drag.

Yeah that is not right. Most of these aircraft cruised with radiator, oil, and cowl flaps closed by design.

You opened up them up for stressful conditions like taxi, climb, or overload conditions.

Crumpp are you ok?......your posts are starting to make sense :)

Im talking about the 109. Maybe its different.

Of course, I got my elevation from an aeronautical information site.

Look under METAR and be advised it changes with conditions. It will vary from 597-600 depending on which site you check.

Here it is 600 today:

http://www.checkwx.com/wxmain/fullsite/EGKB

Sorry Crumpp but this is nonsense and if you are a commercial pilot you'd know it, an airfields official elevation is fixed and defined according to an average sea level in 'official' aeronautical publications not some obscure hobby website, MDA's and DA's are based on threshold elevation and are defined to individual feet, you 'do not' have variable MDA's or DA's according to Wx changes, next time a real pilot lets you look at a Jeppessen approach plate you will see what I mean, having flown a Learjet45 in and out of Biggin Hill on countless occasions due to the company I worked for being based there I believe I can make comment.

BTW EGKB's official elevation is 599 feet as defined in the UK AIP and official charts

linky..... http://www.ead.eurocontrol.int/eadba...2012-05-31.pdf

Really???

http://www.checkwx.com/wxmain/fullsite/EGKB

There is a reason why you have to listen to the current weather!!

:rolleyes:

Yeah and it isn't to find out airfield elevation.

and as usual you display your complete immunity to actual provided evidence to an argument, I linked the the page directly to the UK AIP aerodrome chart for Biggin hill and you still insist that airfield elevation is deffined in a hobby website, next time you look at an official METAR tell me if you see any reference to airfield elevation.

Country United Kingdom
ICAO ID EGKB
Time UTC 0(+1DT)
Latitude 51.330833 - 51° 19' 51.00" N
Longitude 0.032500 - 000° 01' 57.00" E
Elevation 598 feet/182 meters
Type Civil
Magnetic Variation 002° W (01/06)
Operating Agency CIVIL GOVERNMENT, (LANDING FEES AND DIPLOMATIC CLEARANCE MAY BE REQUIRED)
Operating Hours SEE REMARKS FOR OPERATING HOURS OR COMMUNICATIONS FOR POSSIBLE HOURS
International Clearance Status Airport of Entry
Daylight Saving Time Last Sunday in March to last Sunday in October

http://worldaerodata.com/wad.cgi?id=UK47672

598 feet is out of date data and is from a 2006 deffinition, check the link I provided from the UK official aeronautical publication, even the airports own site is using the out of date for some odd reason.

http://www.bigginhillairport.com/wp-...unway-plan.pdf

Lmao!!!

:P

Just curious....


I couldn't get to that link, it gave me 404 (page not found)

I did find this though:
http://www.bigginhillairport.com/wp-...unway-plan.pdf

EDIT: I just saw your last bongodriver but out of curiosity.....

Where do the following fit into this discussion concerning 'the correct' Altimeter setting:-
Apron 600 feet
Height in feet above AD ( 68 )
AMSL 666 feet
Threshold elevations 517 (21), 586 (03, 11) and 598 (29)

Airfield elevations are NOT affected by Temp and pressure. As Bongodriver states they are fixed and come from surveyed state data ... every Professional aviator knows this !

Oh boy that's desperate, laught it up Walt.

ever wondered why elevations are given as (AMSL) above mean sea level, and not above variable hourly datum

setting:-
Apron 600 feet..........self explanatoryand is basically the datum for setting the altimeter.

Height in feet above AD ( 68 )
AMSL 666 feet".............................these 2 figures are actually just a sort of legend simply explaining that the elevations are above mean sea level and the bracketed figures are heights above aerodrome level, the figures in this case are representative and 666' and (68 )appear on every airport diagram.

Threshold elevations 517 (21), 586 (03, 11) and 598 (29).......these figures are the Thresholds and you don't need to set anything., the bracketed figures in this case are the runways, notice wry 03 and 11 share height then look at the airfield diagram you will see its because they are next to each other.

Let me get this straight. Crumpp is now disagreeing with a professional jet pilot who has used the actual airfield multiple times? How many times have you landed a jet at Biggin Hill Crumpp?

http://blog.christlutheranchurch.mb....10/06/mr-t.jpg
.......you know what he says.....

In fairness I'm an unemployed professional jet pilot currently but yeah in essence Osprey has asked an interesting question., Mr Crumpp has been expecting alot of trust from people with claims of being ex special forces and a professional pilot and it seems we have him cornered on one of those claims.

Interesting discussion wheter some obscure airfield in England is 598, 599 or 600 feet above the ground. That's about half a meter.

Should be another 150 pager. Can't wait to see who wins. :D :D

Simple solution to that is to see which one of us is lying, I'm willing to provide plenty of evidence I'm not lying.........Crumpp your call.

I know an even better one, simply not giving a frak about a minor offtopic issue and discuss it in PM. ;)

Well I think someone who makes 'public' claims of being ex special forces and a commercial pilot and may be lying needs to be 'publically' exposed, after all this guy attempting to influence things that affect everyone here.

All pilots have one thing in common, a log, many times a duel signed logbook of hours/model type flown...all could share an image of such records if they were inclined to:cool:

Pilot obtains the field elevation from official publications. Charts being by far, the most common method used.

Even better they have a license and certificates of training records, these days log books can be electronic format which mine is, I'm willing to show images of my license and ratings pages (with suitable editing of things like my address etc, god knows theres a few nutjobs I should keep that safe from)

i know where you live anyway, muhahahahahahahah:evil:

Shhhh! yes thats what I mean about the nutjobs........No my dog doesn't fancy you and never want to see you again :grin:

Ahhhh, you've got such a cute labradoodle, looks real nice in that dress you made for it;)

tmi!!! Lol

Yes safety, then maybe best for two individuals in a dispute, could settle amongst themselves via PM, such records.:grin:

All I know is that I wouldn't buy a second hand car from Crumpp lol

What I said....

The field elevation is under the METAR tab on the link.....

http://www.checkwx.com/wxmain/fullsite/EGKB

be advised it changes with conditions.

Of course it changes with conditions, wow!! :confused:

Your altimeter is just an aneroid barometer.

Readings are taken periodically. That reading is converted to sea level. To do that requires putting the raw data through some formula's that are not dead on accurate.

The actual pressure is generally not static for very long either and changes with the passage of time. Lapse rate is also not standard either.

If you read FAR 91.121, it plainly states the order of precedence you take in setting your altimeter. The station pressure takes precedence over the field elevation.

http://www.gleim.com/aviation/faraim...afNum%3D91.121

Why? If everyone is at the same altimeter setting then you are on the same scale.

Setting the atimeter to field elevation is close to the altitude scale everyone is using but it is not dead on accurate.

The elevation will vary depending on when the readings were taken, where, and which formula's were used to and the standard of accuracy for all but the most busiest and largest of airports is within 10 feet.

If you set your altimeter to the pressure given on ATIS/ADIS then it will rarely be the exact same as the field elevation.

Your eyes and instincts kind of take over at a distance above and close to the runway when it is seen well...your not watching the gauge to countdown to the setting its at:grin:

Wow....now Crumpp is qoting himself, and still linking to a hobby website.

Crumpp, here is the MEATR for Biggin hill (the official one) not one decoded on a hobby website.......decode it and tell me where the elevation data is.

EGKB 091720Z 22011KT 190V250 9999 FEW035 16/09 Q1011

p.s. you have a couple of professional pilots on this forum waiting with baited breath to see what you come up with.

You most certainly do reset your altimeter to the current settings before you take off and it does change while enroute. It is the very first thing ATC will give you at the hand off after radar contact.

It is absolutely essential to safe flight.

Crumps post that he quoted himself from.....

Crumpp don't try and pretend you are talking about QNH now, you have claimed that airfield elevations change hourly according to the conditions and the data is taken from metars.

I was taught to set it to the destination from the chart value, while en route and close. I realize it could be advised differently, elsewhere in the world.:grin:

QNH 1011mb

Are you talking about setting field elevation on the pressurisation system? we usually add 100 feet to ensure the cabin is depressurised before touchdown.

Thats not an elevation figure, thats just QNH

Where have I claimed this knucklehead?

PLEASE point that one out!!

:rolleyes:

OMG....

Obviously you have never set an altimeter. Go into your game and adjust the altimeter setting and watch the needles move and the altitude change.......

Here Knucklehead......where you say you got it from the hobby website and claimed the elevation changes, it does on your hobby site but an airfields elevation officially remains fixed untill the next geographic survey happens.

Bullsh...t!!!

QNH is sea level pressure....not airfield elevation, and I can tell you that even if you have set QNH and are sat right on top of the airfield refference point you won't get an exact reading.

Wrongg.

No pressure system, Cherokee 140 PA-28-140 fixed gear, two seats designed for training. :grin:

OK that makes no sense then, or I believe people here are getting airfield elevation mixed up with QNH....not the same thing, QNH is the pressure setting you set on the altimeter so it reads your altitude above sea level, if you land on QNH then the altimeter will read something close to airfield elevation but not exact, a barometric altimeter is not so precise.
QFE is the pressure at airfield level, it will read close to 0feet +/- altimeter errors when on the airfiled and will give height above aerodrome when flying.
QNE is standard setting (1013) and the altimeter will read your flight level, given that pressure at the surface changes this could be a datum above or below mean sea level.

NO, I said the current settings do not agree with the elevation and not all charts are the same.

Why don't you call Jepperson and ask how many elevation changes they make a year on plates and charts.

Here is the Advisory Circular for it.


http://www.faa.gov/documentLibrary/m...50_5300_19.pdf

When you make a map, there is large room for error both horizontally and vertically. That is why there is so many different datums and it is extremely important you are on the same datum as others in the system.

That is why aerial navigation is by convention.

In fact, Verticle Datum has been one of the most problematic areas in navigation until recent technological advances. Those advances is what allowed us to put JDAM's into multiple cave entrances on the side of a mountain in 2003.

http://www.usna.edu/Users/oceano/pgu...L%20DATUMS.htm

How in hell would any pilot get that confused??????????????

Right so you just posted a load of info explaining how airfield elevations are not changed daily but are calculated using sophisticated surveying techniques which is what I explained, why do they bother when they could just go to your hobby website and get the latest one hourly eh?

That's exactly what I'm saying, it seems to confuse you.

Explain to me Slipball how you are going to get an accurate enroute altimeter setting from the chart elevation values???

The only thing you can do if you don't have a radio is set to the field elevation of the departure airfield.

Once you are airborne, you cannot look at an arrival airfield elevation to glean any useful current altimeter information.

That's true without a radio, and I did set to listed value of chart.

How? are you saying you set an arbitrary QNH based on the known field level at destination before you took off? which basically means you were flying on the wrong pressure setting at your departure.

You are about to be ignored.

Read what I wrote and not what you think or wish it says:

http://forum.1cpublishing.eu/showpos...9&postcount=36

Here it is 597 today:

In otherwords, for you games testing an approximate is good enough. If you set your games altimeter to field elevation, you will get the pressure at sea level.

If you spawn at several airfields around the map, you can see if it changes and confirm the values.

The analog altimeter can be set by either setting the altimeter hands to the correct altitude, or the sea level barometric pressure.

I dare you....

I assure you that Jeppesen, Aerad and other established providers of official aeronautical data will comply with the same values set out in the official AIP of any state, any variations you find on erroneous websites are your problem, us professionals stick to the propper sources.

The barometric altimeter can be set to anything you like within its scale range, if you set another airfields 'guessed' QNH based on it's elevation at the field of departure then 1. you are on the wrong pressure setting for departure 2. the wrong setting for en route 3. the wrong setting for arrival because the pressure could have changed by then.

Crumpp....how many more times are you going to quote yourself?

Enroute and arrival???

No way. You can get a very rough approximate by setting arrival field elevation before you depart and reading the setting off the altimeter. The closer the destination, the more stable the air, the better approximation in most cases.

You can call flight watch enroute but not if you don't have a radio. There is no way to get accurate enroute settings just looking at a chart and using field elevation without physically being on the ground at that airfield.

YES and they change.......

You did not know that as a "professional"? :grin:

Here is Jepperson's plates for Biggen Hill. They went invalid in 2004.

Field elevation is listed as 598 ft.

http://www.cirrus147.com/files/Plates/EGKB/EGKB.pdf

Here is the latest ICAO chart....field elevation is 599ft

http://www.ead.eurocontrol.int/eadba...2012-05-31.pdf

:rolleyes:

So basically you confirmed that since 2004 the elevation was fixed at 598 feet and was changed this year to 599 (after a geographic survey), pretty much what I confirmed several posts back by even linking to exactly the same soursce I did.

So Crumpp, let's see your license, it's easier for you FAA guys, it's just a credit card sized thing, I have to take the pages out of my book and scan separately.

Here's a quck scan of the CAA published official VFR chart for Southern UK in 1:50000, this one is for the Olympics and shows the Temp airspace, this chart is not valid until the 14th of July, please note the airfield elevation at Biggin hill is shown as 599 feet, if the elevation changes daily then why is it published in the charts which are produced annualy? this chart is a companion to the regular VFR chart which also shows biggin at 599 feet and will continue to do so for the whole 'year' of it's validity, and next years edition will in all probability say the same.

Boy. I thought I'd seen some moronic arguments in my time, but this really takes the cake.

I have to disagree Doggles...wildly O/T but a very interesting argument. A lot to be learned from these arguments IMO. And it is not about whether Biggin Hill is at +/- 1ft.

Interesting in that you can see the practical problems associated with having different aircraft flying around relying on pressure sensors (aneroid barometers) that are measuring pressure but displaying altitude or height values.

If everyone sets their altimeters for QNH (current SL pressure), the departure altitude displayed will be close to the surveyed airfield chart height but QNH will need to be continuously updated via radio with the passage of time and distance. Airfields and terrain will be collided with at their correct height, and aircraft in the same airspace will display similar altimeter values, but only if all aircraft are being continuously updated with appropriate QNH via radio.

If everyone sets their altimeters for QFE, height data is only appropriate for the departure airfield for a short period of time.

If everyone sets for QNE (standard pressure), all aircraft altimeters are reading the same flight level (within instrument error), a plus for managing traffic interactions. No updating is needed. However terrain and airfields may appear at different altitudes than physically surveyed data.

Crumpp, it sure seemed, even re-reading, that you were stating that physical airfield elevation was changing in some manner according to pressure and temperature (either physically or to some procedural convention). If you didn't mean that, what did you mean exactly?

Sorry camber, I don't think you can convince me that a bunch of guys waving their e peens around and demanding people post their pilot licences is constructive or meritous.

Terrain doesn't move, barring geological activity. The runway at whatever airport doesn't physically move any significant amount.

Barometer readings do change, and change frequently with meteorological conditions.

A child can understand this.

I agree, though I feel the word is "meritorious".

Relative to sea level, yes and no. There are tides, and they probably move the land as well as the sea.

Beside which the Earth is in orbit around the sun, and moves at many miles per second in that respect.

Yes.

All of it? I'm not sure anyone fully understands the tides yet.