Bf109E-3

[Kurfürst]

Originally Posted by Hunin

Quick first impressions:

1. Cl max seems too low for both retracted and fully extended flaps.
Should be 1.4 and 1.9 according to british testing, 1.3 and 1.62 ingame atm.

Possibly, I'd have to check the Kurvenwendigkeit der Me typen doc, perhaps I can some data for that..

What is behind it that they did a couple of stall speed trials with the Spit earlier, and from the stall speed they deducted Clmax (which in itself lends some room for error, recall those lenghty discussions about what 'stall speed' really is'?). Based on the date, they calculated a doghouse turn chart for the Spi.

When the 109E-3 was handed over by the French for testing, the British wanted a similiar graphical comparison made. They made a similiar test procedure to establish 109E stall speeds, based on that, the Clmax.

at http://www.kurfurst.org/Tactical_tri...ls/Morgan.html

Originally Posted by Hunin

2. Turn time of 25 seconds corresponds with british testing but is significantly higher then the 18. something stated in the official Baubeschreibung.

As noted above, there was no actual measurement of the 109E turn times by British; or if there were, the 25 seconds value was not derived from testing. The Kurwenwendigkeit der Me typen part I. report by Messerschmitt AG calculates the turn time with 990PS on the deck, using proper propellor effiency curves etc.

It gives the turn time for 109E as 18.92 secs on the deck, a fairly believable number IMHO. What complicates things that appearantly we have (ca. 50HP higher) DB 601Aa ratings present, not DB 601A the report assumes. Well say 18-18.5 secs in this case. Actually it should be possible to calculate it precisly using the report.

3. 460 km/h on the deck corresponds with both german testing of Wrk.Nr. 1792
and swiss testing. The Baubeschreibung on the other hand gives 500 km/h.
Any ideas where that difference might come from Kurfy?

I am not sure, but I and others have a very strong suspicion the 460-470ish values are either for the 30-min rating, or due for using the high altitude (2nd speed, FS gear etc.) blower at low level too.

The conditions of the Wrk.Nr. 1792 test are not known for certain, as the report aimed for relative speeds w. and w/o MG FF barrels in the wing, and not absolute figures. Even boost is uncertain, a the report mentions that the figures are not corrected for nominal engine output etc.

The Baubescreibung is the official performance specs for the 109E, which the manufacturer guaranteed to be met withon +/- 5% tolerenace. Those Emils that could not satisfy the specs were not accepted by BAL, the LW's quality control organisation. Even at the war's end!

Moreover the 500/570 specifications laid down in the Bbschr. 109E paper were confirmed with the detailed report of the Emil prototype:

http://www.kurfurst.org/Performance_...w_109V15a.html



and by French testing of Bf 109E-3 WNr. 1340 (same aircraft as tested by the Brits later) also seem to confirm that the level speed figures laid down in the in German specs can be confirmed:
http://www.kurfurst.org/Performance_...formanceT.html
(beware of the bewildering combination of open/closed raditors, RPMs and manifold pressures used.. its a bit of a pity that the French used Hgmm for boost instead of ata. Confusing..)

Besides if one uses simple common sense, its quite easy to see. If you look at the Spitfire and Bf 109E speeds and powers at rated altitude, you'll find that that both do around 570 km/h, but the Spit has actually quite a bit of more power at this altitude (as opposed to popular knowledge, the Merlin III was pretty good at alt). It follows that it has more drag. Now, at SL the Spit does, iirc some 282 mph at +6 1/4 boost, which is 890 HP. And the 109 there has 990 (601A-1) to 1050 HP (601Aa). It follows that should be a good deal faster than 282 mph (454 kph), with 150 HP extra in less draggy airframe..

Just as a side note: 5% of 500 kmh = 25 kmh, so a 475 kmh fast Emil would still have been accepted

Just wait and take a look again when mixture ratio is fixed. This might in fact lead to more nominal values when finally this parameter can be optimized.

When talking about drag one has to be a bit cautious when saying which airframe is less draggy when talking about flight operations as drag is composed of friction drag and induced drag. The former is due to friction over the skin and therefore mainly dependent on speed and altitude, the latter foremost dependent on angle of attack. So it might be (might be, I don't say that it should be but yet could be) that the spit just had to fly at an angle of attack at high altitude that went along with higher induced drag while it had to use less angle of attack at lower altitudes and therefore had less drag. Actually it is quite reasonable to assume that this is indeed the case. When the air density decreases the plane has to increase angle of attack for level flight but then can reduce angle of attack with tanks more empty. The behaviour could be very much different for the 109 and the Spit. I cannot tell in which ways.

[Kurfürst]

Originally Posted by 41Sqn_Stormcrow

Just as a side note: 5% of 500 kmh = 25 kmh, so a 475 kmh fast Emil would still have been accepted

Just wait and take a look again when mixture ratio is fixed. This might in fact lead to more nominal values when finally this parameter can be optimized.

Top speeds at SL and rated altitude are coded (ie. set by developer manually. Currently its 470 at SL (which is double wrong as I suspect it should be attainable only with the 1175 PS rating instead of the actual 1045 PS rating), and 560 at 4500 meter for the Emil). I guess the engine works out the rest of the graph from these figures (its pretty obvious between SL and FTH, the above probably follows the same rules for all planes, taking into account stall speed, which is also manually set.

Originally Posted by Kurfürst

Top speeds at SL and rated altitude are coded (ie. set by developer manually. Currently its 470 at SL (which is double wrong as I suspect it should be attainable only with the 1175 PS rating instead of the actual 1045 PS rating), and 560 at 4500 meter for the Emil). I guess the engine works out the rest of the graph from these figures (its pretty obvious between SL and FTH, the above probably follows the same rules for all planes, taking into account stall speed, which is also manually set.

Oh. If top speeds are hard coded then that is not good. This shouldn't be the case.

[Pluto]

Originally Posted by doghous3

I started ranting about non-CEM MP server's. About how the BF109E performance is nerfed. It is but I did some research just after on the planes.

It turns out that the Spitfire could fly faster than the BF109 at level flight. Could dive faster. Obviously out-turn it, and if I remember rightly, could climb better too.

It was said that the German pilots would rely on their wingman when dealing with the Spitfire.

The BF109E did perform better at high altitude though.

I'll try to find the article again as perhaps it's information wasn't truely correct, but it was just a random google search. Sorry for no link.

Sorry but that sounds like crap, in reality the 109 was faster than the Spit and it could dive faster, the Spit could fly tighter turns and was more agile in dogfights. I learned that years ago from a real pilot who was flying in the Battle of Britain the 109. If it is not like that in this sim, it is simulated wrong and needs to be patched!

[Kurfürst]

Originally Posted by Hunin

;
[Params]
;

SpinCxLoss 0.06
SpinCyLoss 0.03

Vmin 170.0 kmh
Vmax 470.0 kmh
VmaxAllowed 750.0 kmh
VmaxH 560.0 kmh at 4500.0 m
VminFLAPS 130.0 kmh
VmaxFLAPS 250.0 kmh
Vz_climb 20.0 ms
V_climb 270.0 kmh
T_turn 25.0 sec
V_turn 340.0 kmh
K_max 13.0
FlapsMult 1.0
FlapsAngSh 10.0

RangeAbility 480 km
;

I took a look at the figures above and compared it to my documentation. See the suggested values below:

?? means I have no idea what the figure is for..
Changes are marked with bold, with source given.

SpinCxLoss 0.06 ??
SpinCyLoss 0.03 ??

Vmin 170.0 kmh - should be 153.0 kmh -
[i] this is for a throttled down (~power off) engine as the UK Morgan report posted above. It needs to be found out what 'Vmin' means in the sim, since in real life, the stall speeds are about 10 mph lower when the engine is opened up (propeller helps the wings, relative airflow speed is higher than airspeed would indicate -> more lift). So if the other planes are using Power ON stall speeds, this should be not be used but a lower stall speed value.[i]

Vmax 470.0 kmh - Should be 520. Now a bit of a comment would be needed here.

Vmax for the 109E-3 with DB 601Aa should be 500 kph (see Baubeschreibung 109E graph posted above). This was achiavable with the 1,35ata rating 5-min (1045PS at SL) and guaranteed within 5%.

However I believe this figure (the 470 kph one) is to be achieved only by using all out boost in the sim, and that is what the testing shows: 470 can only be approached by using the 1-min WEP (W button), ie. 1,45ata. This latter translates to 1175 PS at SL...

If this is the case, the Vmax. should bet 500+, at around 515-520 kph (deducted as power requirements increase with the cube), achiavable in the sim w. the 1-min boost, and so that the proper max. speed (500) could be achieved with the 5-min 1,35ata/2400 rating.


VmaxAllowed 750.0 kmh - correct. Appearantly Il-2COD does not differentiate for dive limit changes with altitude.
VmaxH 560.0 kmh at 4500.0 m - should be 570 kph at 5000m, as per Baubescreibung curves
VminFLAPS 130.0 kmh - this matches the UK Morgan/RAE report for 109E with flaps fully down
VmaxFLAPS 250.0 kmh - note: this is for fully deployed flaps, for example 20 degrees flaps were allowed up 500 km/h
Vz_climb 20.0 ms - its unclear what this is for, presumably initial climb rate. If so, probably correct if it's understood with 1-minute WEP; if meant for 5 minute rating, too high IMHO. This is based on analysis of German, French and British measurements, and the 109E Baubescreibung.
V_climb 270.0 kmh - should be 250 km/h, as per the Emil 1939 short manual.
This might be significant as it will result in steeper climbs, a working tactic described by UK evaluations for the 109E.
T_turn 25.0 sec - should be around 18-18.92 sec for SL, as discussed above.
V_turn 340.0 kmh - this needs to be re-calculated I think due to the previous change.
K_max 13.0 - ?? No idea what these last three are for..
FlapsMult 1.0
FlapsAngSh 10.0

RangeAbility 480 km - Should be 665 km?

This is probably for range, but its entirely unclear to what altitude and engine setting this should be true. Developer would be needed to comment on this.. In any case, German range tables give economic cruising range at 650 - 665 km for the Emil, pretty irrespective of altitude (different engine setups were, however, required, ie. pitch, rpm, boost etc.).

[unreasonable]

It is possible these "hard coded" max speeds and ranges only affect AI or the generation of missions in FMB in some way as opposed to the player FM, insofar as these may need to have access to a/c specific data in a shorthand form: a bit like the hard coded "cruise speeds" in IL2 classic IIRC.

[Sauf]

Both the E-3 and E-3B are overweight by default, am maybe stating the obvious but is this taken into account with peoples test flights?

[Xiola]

Really the Spitfire II shoould not be common through the battle as far as I can remember.

It should be the Hurricane or Spitfire 1 vs 109E.

Spitfire II only really arrived properly after the 'official' Battle was over' IIRC, so Multiplayer servers should not include it too often IMHO.

It was more a Oct '40 to april '41 aircraft

[JG53Frankyboy]

i am sure the Spitfire experts will give you other dates for the Spit II soon
just in short, it fought in the BoB long before 31.october

as the not in game beeing Hurricane II too