4.11 overheat and engine damage test results
 

Hi,
some folks are seriously concerned that some planes might overheat too much in 4.11, while others might overheat much less.

Specifically, Whistlinggdeath feels that the TA152H, P51 and FW190D9 45 overheat too much, especially during zoomclimbs, while the I-185 M71 and SpitIX 25lbs show almost no overheat.

Us JG27 folks have tested 4.11 extensively in internal fullreal matches and found no reason to worry. However, dogfights are not objective, specific tests.

To get some reproducible numbers, i've put several planes to the ultimate overheat test on the crimea map: with the plane grounded, chocks in, pp 100% or auto (where available) i ran the engine to absolute max power, measuring the time until the overheat message appeared and until engine damage occured. Full power was applied immediately after engine ignition.
I repeated the test at least 3 times per plane, and calculated average values as well as standard deviation (displayed as error bars).
Unless stated otherwise, radiators were open.
I've also plotted engine rpm at max settings.

This test provides an estimate on how fast a plane will overheat when reaching very low speeds at full power, as happens at the top of some zoomclimbs.

For a given plane, the time to overheat is highly reproducible (small error bars, see figure below). The error bars get a little bigger for the time to engine damage, where random effects come into play.

As you see, all planes overheat pretty fast under the given circumstances, and the differences between planes are minor. In my view, there's no reason to worry.

Contradictory to Whistlinggdeath's description, SpitIX 25lbs and P51 D20 overheat at almost exactly the same time.

The TA152 H1 overheats slightly faster than the Spit with radiators on auto. With manually opened radiators, however, the TA overheats slower than the Spit! This trend is also seen for the FW190D9 models, but not for the 109K4 and P51. In summary, the automatic radiator opens a little late on the TA and D9.

The most overheat-resistant planes in this test are the FW190A6 and the I-185 M71.

http://i25.photobucket.com/albums/c6...Overheat_1.jpg

It seems that rpm values and overheat times correlate inversely: planes with low rpm (I-185 and FW190) are slow to overheat, while planes with high rpm (TA152) seem to overheat faster.

To test this hypothesis i plotted the reciprocal of RPM values (1/RPM) against the average time to overheat (open radiators, see figure below).

As expected, both curves are very similar, and this impression is confirmed by the calculated Pearson correlation coefficient between RPM and time to overheat. The correlation value of -0.56 indicates a fairly strong inverse correlation between engine rpm and time to overheat. In other words: high rpm results in faster overheat, across the planeset.

http://i25.photobucket.com/albums/c6...Overheat_2.jpg

***EDIT***
I've just tested the TA152, FW190A6, SpitIX 25lbs, LA7 3xB20, F4U-1D and I-185 M71 inflight on the same map: max performance takeoff and climb at a constant 260kph IAS.
I used manually open rads on the TA, FW190 and I-185, auto rads for the spit.

Here are the times to overheat at 260kph IAS:

Plane_________time to overheat____notes__________________
TA152-H1........3'24''......................oil temp near upper limit
SpitIX 25lbs.....2'56''......................oil at 80°C, glycol at 110°C
FW190A6.........3'48''......................oil at less than 80°C
F4U-1D............3'52''.....................oil temp 80°C, cylinder head 200°C at overheat message
LA7 3xB20........3'48''......................oil temp is above 100°C from 1'56''on; cylinder head temp above 200°C at overheat message
I-185 M71........5'08''.....................oil temp is above 100°C from 2'08'' on; cylinder head temp above 200°C at overheat message

Something seems to be wrong with the I-185. For one, it overheats on the ground just like any other plane, but much later in the air.
While most other planes overheat when the oil has 80°C, the I-185's oil temps hits the end of the dial (125°C) before the overheat occurs. At that stage, the cylinder head has well above 200°C. This behavior is very different from that of other radial engine fighters in the test (F4U, FW190A). The LA7 also shows that oil temp increase, but the overheat message comes earlier, at almost the same time with the FW190A and F4U.

Maybe someone from TD could explain why the I-185 is different?
***EDIT END***

Cheers

Well done! Thanks for the detailed information.

My question is whether aircrafts equipped with MW50 really overheated that fast in real life. According to the test it cannot even last more than 2 minutes in the game. The only radiator position that is useful for Luftwaffe pilots are full open. I can't think of any situation where other positions can be used.

And I can't persuade myself to believe those coarse Russian engines tend to has less overheat problem than German ones.

BTW, 109 K4 C3 appears to have a flawed auto radiator. You can notice the radiator flaps are not fully open even the engine has been overheated for a long time.

MW50 merely allowed higher boost pressures and the max time to run that higher boost was 10 minutes after which you needed a 5 minute break.

That restriction is totally separate from any other limitations on running the engine at takeoff/miltary power at low airspeed. If the engine had a separate restriction on for example time at takeoff power that still applied over and above the 10 minute WEP restriction.

Running MW50 did not magically give the engine the ability to disregard its normal restrictions its cooling properties were a side effect and minimal. People seem to think if MW50 was permitted for 10 minutes then the engine should last 10 minutes regardless of how you mistreat it. That is just silly.


Gratuitous MW50 operation instructions in German :

http://i18.photobucket.com/albums/b1...0_im_Bf109.jpg

1. It can not last two minutes stationary on the ground without any air flowing through the radiators to actually cool it. That is what this test established as he tries to mimic a plane at stall speed at the top of a zoom climb. If your plane is constantly in that state you are a rubbish pilot.

2. Other positions can be used during 90% of a regular pilots flight time. Prolonged combat against top brass planes and pilots are rather rare actually. Even on a dogfight server, if you know what you are doing.

3. Exactly because of their rather rough nature they are more rugged.

Let me translate that first sentence, the most important of them all, for jermin.

"What is MW-50 operation?
MW-50 operation means: Temporary extraction of emergency power for the purpose of hoirzontal and climb speed increase, allowed by boost pressure increase to 1,7ata and simultaneous injection of MW-50."

So, as I told you before, it is not meant for the pilot to give him an edge in zoom climbing or general fighting, but to increase his speed to get out of trouble.

And also the La-7 - if you look at your chart.
So whats unique on these three planes - contrary to the others? ;)

Nice testing, BTW!

Where's the difference? The engine still can not last over 5 minutes even during level flight.

Have you tried it yourself? Fly some sorties in some hot servers on hyperlobby and see for yourself whether you will have a chance to fly using other radiator positions.

Sorry, but I can't see your logic here.

Where does it say it should be used to get out of trouble?

you never climb and accelerate during combat? What if your plane can not outrun the enemy aircraft on your 6 and it is more agile than yours? So will leave MW50 disabled and wait for enemy ripping your ass off?

Don't pretend to be a WW2 veteran, will you?

I think he is merely stating facts.

There is still the unanswered question if the Komandogerät allowed the TA engine to overrev in dive at 110%+Wep+autopp.