109E bugs as of final patch

[*Buzzsaw*]

Originally Posted by Kurfürst

Please add your own to the list.



Currently the 109s have the following issues:

- auto prop pitch bug on the E-4. It needs to be switched on, tempered with in manual, and then switch back to actually work
- None of them can reach historical level speeds and is slower by ca. 40 km/h
- altitude FM bug (common to all planes)
- pilot/fuel tank armored bulkhead is not modelled
- stall modelling, with unpredictable and violent stalls, flat spins
- it overheat model is much worse than the real thing, which could sustain allowable temperatures at 1/4 radiator open (or 3/4 closed) in level flight
- the weight of E-1, E-3, E-4 is slightly off (though I do not think this is that much of an issue, since turn times are hard coded and it should only effect behaviour)
- ground handling model is simplistic (common to all planes)
- best climbing speed is off, it's 270 km/h instead of 250 kph, which may seem unimportant, but it has an effect on the turn/climb envelope, curve and related tactics, low speed flight etc.
- tail wheel lock is present in 3d cocpit model (it was present on E-7 onwards)
- speaking of which there's no E-7
- no E-4/N either :p
- manual prop pitch lacks feathering option (historically setting the level to the lowest position set the airscrew to be feathered)
- armament signal lights are wrong in cocpit

Salute

I am going to actually agree with Kurfurst on this approach... ie. an objective one free from hyperbole. Yes, we can disagree on certain points, but lets stick to the facts.

Some of his points are up for debate, ie. the actual amount by which the 109's are slow at sea level and above. He suggests 40 kph, I believe closer to 20 kph. There has been a very detailed thread posted on this subject on this forum.

Specific to the engine issues:

They have given it the DB601Aa engine, instead of the more common DB601A1. (Aa equipped only about 25% of 109E's)

But then, they have given the engine the rated altitude of the A1's 4500 km, instead of the 3700 km of the Aa.

The historical Aa had a limit of 5 minutes at 1.35 ata, the game's engine has an unlimited time at that boost, which was actually the allowable rating for 1.23 ata. (actually 30 minutes, but close enough)

Here's another glitch: They have rated the engine at 1020 PS at at 4500m at 1.35 ata, however, that is the power output and rated altitude for the DB601A1, and that engine achieved its power at 1.30 ata. The DB601Aa was rated at 1100 PS at 1.35 ata at 3700m. So they are down 80 PS on power the engine provides at rated power between 0-3700 meters. That is, if it is an Aa engine they are modelling.

In my opinion, the game 109 seems to be suffering from a lack of efficiency in the ability of the supercharger to maintain power, it falls off much too fast with altitude, if this plane is the Aa, then it should actually be constant with its rated power to 3700m, or if it is the A1, to 4500. (the British planes also fall off in their efficiency, but I think that is for a different reason)

The performance the aircraft should achieve doesn't happen at sea level, and it gets worse the higher it goes. And this is even though the aircraft could be underweight by as much as 125 kg depending on the model.

A lot of the speed issues are related to the engine issues, although as Kurfurst says, some are also related to the rad settings.

Here are some documents from Kurfurst's site to illustrate my points.

DB601Aa



DB601A1



In my opinion, the 109's should be faster at sea level to 3000 m, and over 3000 m, and in particular over 6000 m where performance really falls off, the entire performance envelope, speed and climb, should be better.

Concurrent with this performance improvement, they should be able to attain their historical ceiling.

At the same time, they should be more prone to overheat when using 1.35 ata, unlimited use of this setting is not realistic over the 5 minute allowable historically. And further, 1.45 ata should cause considerable overheat when used in continuous intervals. As it stands now, the game aircraft can be flown with a pilot basically ignoring the historical limits.

Weights should be adjusted.

As far as stall characteristics are concerned:

In relation to stall onset I do not find the 109's differ much from the described characteristics testers actually found. In my experience, the tendency to drop a wing in level flight stalls, power on and power off, is less in this aircraft than any of the British planes, but reports did note that under hard G turning, it would flick or drop a wing at stall.

However, stall/spin recovery does not seem to be modelled at all correctly. All the reports indicate recovery was very easy in this aircraft, within a single rotation, the opposite of what seems the case in the game. I don't know how many 109's I have seen spinning to their deaths from altitudes of 1000 meters. Recovery should be much less than that, with height loss probably in the area of 300 meters distance.

Ground handing is modelled completely inaccurately in the aircraft. The 109 was tail heavy, it showed no tendency at all to nose over under hard braking, it was the opposite of the Spitfires. In fact, the pilot had to give a burst of power and push the stick forward to allow the rudder to steer when taxing. At the same time, the aircraft also had directional issues as a result of its undercarriage placement, and the off-camber angle of its tires. It would change directions if one wheel or the other came off the ground, and landing other than in a three point mode was not recommended. None of these are modelled.