Spit IIa Performance graph
 

S! Everyone

So... im sorry for my english, ill try to be clear :cool:

Patch used BETA PATCH v1.06.17582 + HOTFIX

Today i was collecting datas to plot this graphs, maybe this information could help producers to modeling correctly the engines and for us, pilots, who want to know what is the better engine setting and aicraft topspeed in simulator.

So he we go with this PDF file.

I test speeds at 3000rpm, 2800rpm and 2600rpm Full Throttle and WEP.

Be carrefull with overboost at high altitudes, the supercharger injects hot air in the engines, so if you dont care, you can blow your engine to fast.

All the tests start with one spit IIa, full tanks, full ammo, pilot with parachute.

I start at ground, Sea Level at Manston Air Field, sun weather.

I prefer start at ground to be more realistic in simulation, we start at ground and set our engines to climb, there is a fuel burn rate at the altitude desired and begin the data collects.


hope you guys enjoy, and i hope this datas help you to decide better tatics against 109´s, i have my opinion, if someone wants to know just ask, ill be honor to post here!

S! gentleman! ;)

Pretty pathetic. The boost levels @ RPM and speeds are all wrong. It's hard to believe how anyone could produce such a poor simulation:

http://www.spitfireperformance.com/p7280-speed.jpg

The player selects the boost and rpm......

Which is realistic. At high density altitude, you will see a performance decrease at high boost and rpm. What happens is the prop tip speeds become excessive and you lose efficiency. So instead of increasing thrust, you actually reduce the thrust the propeller is able to produce.

In otherwords, at standard conditions and low density altitude you have the chance of realizing a performance increase at high boost and rpm.

You can also see by your test that the 2800 rpm data is almost an exact match looking at SL and your test FTH on a standard day. Your recorded FTH is off though for a standard day.

However, the FTH does not match 29.29inHg at 66.2F.

What are the temperature and pressure you recorded the data under?

I am not sharp shooting your effort. Trying to help you guys get the data you want to make sure all the FM's are correct. If you don't give the developers the information they need, then they cannot find the issue and fix it.

Some details that need to be included in each test:

Take off weight

There is a control somewhere to set the temperature and pressure. If you can set them too:

SL Temperature 15C
SL pressure 1013.25mb

Climb speeds

Engine settings and rpm

FTH

You have a well organized set of data that is easy to work with combined with visual graphs to spot trends. That is great.

Don't forget too that the details of the RL performance are extremely important as well. How the aircraft is set up, weight, configuration, etc...

All of these effect performance.

Lastly, aircraft performance is a percentage range so looking at a single set of data from a real aircraft may not be representative of the typical performance of the type.

For example, the Spitfire test P7280 does not seem to have a rear view mirror listed.

http://www.spitfireperformance.com/spitfire-II.html

The absence of a rearview will effect the Vmax of the airplane in the Spitfire. The presence of the mirror is noted in RAE test's.

Aircraft performance is all about the specific conditions!

I'm getting really tired of your B&*(&*^t. It was virtually impossible to destroy an engine at high altitude because the engine simply can't produce enough boost to cause damage. High RPM was necessary to produce sufficient boost for the engine to develop maximum power. The boost at altitude graph that I posted earlier shows the engine holding 8.8lbs to 17550ft at 2990 rpm. The idea that somehow the engine would destroy itself at these boost levels is complete nonsense and shows how the simulation at it's current state of development is complete crap.

Watch your language...

On the topic at hand, going fine pitch/high RPM while flying in low-density air decreases performance after a certain point. The air is "thin" so you need to coarsen the pitch (lower RPMs) to get a sufficient bite of air, otherwise the prop just spins around really fast without pushing the needed amount of airflow.

It's modeled the same way in 109s by the way (you get better performance if you drop your RPMs a bit at higher altitudes) and it's one of the first things i noticed and really liked in the sim.

The engine cannot produce maximum power unless the supercharger is spinning at maximum speed to provide maximum boost. The effect of prop tip speed is practically unnoticable with BofB RAF fighters at RPMs of 3000 or less because the props were designed to provide full power at this RPM and were sized accordingly.

I thought we decided that the atmosphere in game was way off the mark?

Not completely, there is a setting on the FMB which brings the atmospheric temparatures in line with ISA, but by default it seems the atmosphere is modelled as ISA + 10 which is perfectly feasible in the real world in summer time, with ISA +10 we can expect to see an underperformance from what is stated in aircraft flight manuals, the results of my atmospheric tests are in the hurricane speed thread.

http://forum.1cpublishing.eu/showthread.php?t=32523

at some point I wan't to check the pressure lapse rate but I don't think it makes for as big an issue as temparature.

Good afternoon gents

so, takeoff weight = maximun takeoff weight

Temperature and pressure default, default settings and weather...

Climb speeds at 160mph @2600rpm - full throtle - better setting to climb.

Tests under 115ºC water temp. oil temp under 95º - maximun ºC permited under emergency purpose.

Actually if you want a good comparisson to the flight manual data then it would be worth creating a quick mission with a parameter changed which brings atmosphere to standard, look for Breeze/Thermal factor in the mission parameters in FMB and set it to 0, if the performance is off under those conditions then we know there is a problem.

That might be a map-wise setting, hard-coded lke we used to see in 1946. Be interesting to test if/when BoM comes out.

did you check that thread I mentioned? the Breeze/thermal factor slider in mission parameters in the FMB changes the temparatures and set it to 0 you get pretty much standard conditions, with further experimentation I'd like to find out if there is a way to get ISA - conditions.

That is one of the details I really like about the sim too.

The best thing is the mindset it forces upon a player. You have to keep a scan going even during a dogfight and above all "fly the plane". That fact alone makes it a better simulation than anything to date.

Actually it is the fact the engine supercharger can produce boost that can damage it.

It would be pilot error though as if the POH instructions are followed, it will not occur.

You don't lean an aircraft engine in a climb below ~5000 ft Density altitude. Leaning can cause detonation.

In a supercharged engine, the supercharger keeps the density altitude in the manifold low below FTH and below 5000 ft for all or a portion above it depending on the specifics.

For example, in the Spitfire you are instructed to leave the mixture control in NORMAL. It has a WEAK setting and if used, the POH instructs that the boost is limited to 3 1/2 lbs except for short periods.

If you tried to climb at the normal climb rating in WEAK mixture, you could cause detonation and destroy the engine.

I did, yes.

What I meant was that, perhaps the slider in FMB allows us to change the pressure in the relative sense.

I.e. The difference between 0 and 10 on that slider might not produce ~ISA and ISA+10 on a different map, which is what I meant by "map-wise setting" ;)

It will be nice in a couple of years to if/when we get some FMB documentation.

We know the lapse rate is 1.98C/1000ft, right?

Set the altimeter to field elevation and read the window to get pressure. It is close enough.

Have someone spawn with an aircraft that has an OAT gauge and read the temp at that field elevation.

You have the data required to convert the performance for that map.

Ultimately I think you are right on that one, the sliders effect is probably coincidental, it really seems geared around some basic enviromental effects, you can set layers or bands of the effect at varying altitudes, my guess it is just for simulating turbulence at varying levels and the associated air temparature mixing.

No it is the weight of the aircraft configuration you are flying.

Note the weight of the plane @ take off and not "maximum take off weight" as per the POH.

So this control slider does not exist to set conditions to standard?

What needs to happen is a plane with and OAT takes some readings at altitude.

Then you know for sure.

The purpose of the control is not self-evident. It appears to be able to set them to something approaching standard, on this map.

On a different map, it might not, which is what I was saying needs to be tested when we get another map.

Seems like it is going to be easier to just record the pressure, temp, and convert performance to standard.

Looking forward to your results!

Right next to yours...

:rolleyes:

Hey everyone! Thx alto for tour comments and discution. Ill try to be more acuraste in This tests changing in fmb that parameters of weather and pressure.

Im very happy to comunicate you one good thing! AN team, including me, will make more tests in all RAF planes and will post the datas here in this forum for health discussions like this!

We will try to improve this simulator with this datas to all of you analize!

Cya guys! and thx

Test all of them, why just the RAF planes?

Maybe testing them is time consuming and since =AN= flies for the allies those planes interest them the most?
It's allready great that they are expanding these tests to all British fighters and not just the one or 2 most commonly flown ones.

Thanks Felipe, looking forward for your tests. Much appreciated!

Thx you guys for oportunite!

We dont fly german planes, maybe in future we can lern more about 109s and other to test, it we be another project for sure!

;)

ok :)

Hehe, attention, specialists @ work (again) :rolleyes:
You do realize that there was no talk at all about releasing a 100oct MkII (or fixing that), do you?
Oh, and I agree, Atmosphere should be ISA and ISA only. As we all know, it was 15°C in the summer of 1940!

Yeah Redroach just like the pressure was 992mb in summer too. :rolleyes: We know the temp was not 15 but have a look through the records and see if you think 992 is a good fit for the battle.

They either need to publish what the atmosphere is actually doing so proper conversions can take place or create a "test map" that has ISA conditions. So verification and "informed" discussion can take place. You would think they would've created such a map when they were beta testing. Oh that's right we are playing the Alpha.

If it would help, I will post step by step how to convert the data from non-standard to standard.

Guys one more week ill give you a new feedback and new data files, i have to travel this week so ill be off, when i return ill work hard to bring this datas to you with more colums of variable like watter temp and oil temp. Etc...

Crump we are studding about german fighters, if you guys have accurate documents about speed tests or another tests for 109,s or other german planes give to me plz! felipe.borkowski@hotmail.com



Thxxxx:-)

I have some and maybe Kurfurst will chime in. He has all the 109 stuff.
Because of the museum and restoration company, most of my stuff is P51 and Focke Wulf related.

Ok! thx again =)