Anatoli-Kagari9

Speed, but also pitching moment.

NOTE: Further tests revealled I have done something wrong when I initially tested it... Has it vanished ? A friend who also used the p51d allerted me to the fact that one of these days he was at an aerobatics server and only noticed he had forgotten to raise the gear when he saw the shadow of his aircraft on the ground. I picked the p51d for a few test flights and indeed their appears to be almost no differrence from flying with or without gear out ? I recall that there was some noticeable drag some versions ago ( ? )

Thx Yo-Yo. I now actually use manual prop pitch most of the time, from takeoff to landing and even in dogfight. Will try at 1.1, see what revs it choses, and then use manual pitch to attain that same revolution and see if speed varies :-)

Interesting note 5tuka, and I believe it's very important. I too notice an interrelation, sometimes, between it and AoA / sideslip. I wonder, nonetheless, if it may somehow relate to the way some prop effects, namely p-factor, are modelled in DCS World. In cruise, with your aircraft properly trimmed for almost null stick force ( for pitch ) but with the aircraft flying wings level but in a sideslip, using rudder to coordinate will translate to a significant pitching up moment, that, if left on it's own will easily bring the 109 to a loop! Mind that during this strange situation, you need / should not touch throttle or prop. I believe I've tried only with automatic prop pitch, so I will try to make sure the same is observed with manual prop pitch, which is now what I use most of the time.

Ala13, I believe you mean Gyroscopic effect. Gyro and P-factor in DCS World aircraft are tuned in a way that I find in no other flight simulator I have used, with the only exception being the first version of Flight Unlimited ( released around 1995 ! ). As your aircraft takes of at higher power settings, the tendency to swing to the left, and specially while the pilot keeps the wings level as much as possible, results in a necessary pitch up due to gyroscopic effect. P-factor plays a similar role inflight when you make power adjustments while cruising and use rudder ( or rudder trim in the P51d ) to coordinate.

Found, thx to a post at another thread, that simply setting AA to 2x in game ( or even None ) and Anisotropic Filtering to None, gives me visual contact a lot better at distance when playing at the WW2 MP servers. I am running with my monitor native 1920 x 1080 resolution.

Did it a couple of weeks ago, when I finally decided to completely drop any more investment on present civil sim platforms ... and not to spend my money in the FSLabs A320, but instead, invest more in DCS amd IL-2 BoK and collector planes :-) Really looking forward into it !

In two of the AS-K21 gliders I used to fly 90% of the time the left wing would drop on stall. Regarding some interesting features of the 109 series, specially a comparison between E and G models, this interview is a great source of info. At around 16:31 the pilot starts talking about how the 109s stalls compared to other ww2 fighters - interesting to notice how close to our experience in DCS actually is . https://secure-hwcdn.libsyn.com/p/f/9/a/f9a4e46e96be2a2e/Episode_32_Warbirds_Over_the_Beach_BF-109G_Pilot_Rick_Volker.mp3?c_id=11781892&expiration=1479639140&hwt=59b3f03317bc360b9372993904cbf95f

Can only talk based on my RL experience with gliders, the Astir CS Jeans and the Phoebus C, which can have that sort of stall we call "mushing stall" where your nose is almost perfectly aligned with the horizon, and you have still plenty of aileron authority.

I believe he means actually being able to get a view perspective such as that which is possible IRL, when you "put your head" outside of the cockpit to look ahead or behind without the glareshield interfering...

Where's this P-38 available ? Ok, just found it :-) https://forums.eagle.ru/showpost.php?p=2811269&postcount=356

I lent my Bf109 K4 module to a friend for a few weeks so I can't test those dive experiments ...:-( It's my 2nd 109 module... I love this aircraft ( well the same happened with the 190 and the 51d, the uh1h and the mi8 - bought them all twice :-/ ), and all aspects being considered, the level of quality / detail / complexity in these modules is really Special!

Never mind SiTh, someone provided me with links that reminded me about this rather old thread, and even the messages I exchanged with Klaus Plaza and seem to confirm this pitching up tendency.

Ah, that's from two moments in JCOMM's time, which is even more intricate than string-based time.... I wrote the first post before deciding, a few hours latter, to re-install DCS and give it a new try... I was willing to find out how it felt a few versions after I left it... Overall I'm glad I did it, and even spent some time yesterday at a couple of ww2 ervers. Then, DCS has this great change of borrowing and lending license keys. I actually have bought the ww2 modules twice, and so I could still reinstall the three, but regarding the helicopters, the l39, a10c and f86, I can still ask them back for a while from the friend presently using those licenses - a feature which to my knowledge is unique to this sim and I find superb! So, back to WW2 in DCS addiction. I never played modern combat with the jet's - too complex for me...and for that level of complexity I really prefer to play other games like simulating the operations of a Boeing 747-400 in my Aerowinx PSX :-)

Hi Sporg, thx for reminding me of that thread. It had been a while since I last played DCS... I even contributed with some facts I gathered from some emails exchanged with Klaus Plaza, that actually confirmed the pitching up tendencies... :-/ Let's leave it as it is - probably closer to real than anything else...

Well, been testing the latest beta version 1.5, and the 109. Regarding this old subject, and loading fuel only up to 60%, I have made a few test flights and indeed the pitching up moment feels as having been tuned down. Regarding the need to use fwd stick most of the time, even with full nose heavy stab trim, I still ask myself, comparing to my RL experience, what the trims are made for, in non-fbw aircraft ? Isn't it to release the pilot from these forces ? Or, as I often do in my glider, to increase those forces in order to avoid unwanted effects ( I always set the gliders nose heavy for approach and landing, in order to positively feel the force needed for flare... ). The 109 has a fixed, ground adjustable elevator trim tab. What might it be used for other than to exactly fine tune this need to use stick fwd during takeoff or level flight over a wide range of speed and power settings ? Why have the two other trim tabs ( aileron and rudder ) been made available to set in the aircraft settings, but not the elevator trim tab ? If I were a 109 pilot I would certainly ask my ground crew to adjust it for me, then try to fine adjust it based on a series of flights... and I would certainly seek for a setting that would clear out that odd need to use significant fwd stick as soon as I leave ground as it is in DCS... That's what trims, and trim tabs are made for, I guess....

Thx Ala13 :thumbup:

Ok, at least you got me re-installing DCS 1.5.4 beta just to check how the 3 ww2 fighters have progressed through the latest patches... Didn't have much time to test yet... but on a takeoff using 60% fuel, with trim set for +1.0, I found less pitching up moment than I used to the last time I tried it some 3 months ago... Will test further ASAP and report.

I believe that's due to an internal flight dynamics model limitation - not being able to have a 2nd order trimming ... stabilator + elevator trim tab like in the real aircraft, otherwise they would have added that option as they did for aileron and rudder. IMO that's also what distinguishes the ED Bf109 K4 from the 109s in the other mentioned simulator, which models both the stabilator ( of course ) and has a trim tab, set at a fixed position but properly calibrated to allow for more realistic feel ( as far as I believe to be the case IRL ) regarding pitching moments. On that sim, with the aircraft on ground, braked, one can actually observe the elevator move (and the stick in the cockpit too ) due to propwash when the engine power is increased during a run-up, because the elevator trim tab is set for nose heavy ( deflected up at a fixed position as can be observed by zooming into it ). Anyway, it's been a while since I used DCS, and this particular module, and I've read somewhere that there was some fine tuning done in the latest releases ( ? ) and that this pitching moment effect had been tuned down ( ? )

It's been a long time since I last used DCS and I don't even have it installed, so, couldn't test this myself... hence the post.. I've seen there have been developments in the Bf 109 lately, and I wonder if the old pitching up moment tendency, under most configurations, has been smoothed out ? It could be overcome by using a controller pitch axis curve mod, but that was not the right way to do it, and could affect other aspects of flight, so I wonder if this is now different in the release version with the latest updates. In the past there were many threads about this issue. Thx for any feedback!

The only thing that comes to my mind is that in 2.0.3 you're flying in Nevada, right ? The altitudes, and temperature, and hence density in Nevada airfields, as opposed to most of the airfields in the Caucasus map ( almost at sea level ), can play a major role in takeoff performance...

Depends Sporg. At higher power settings, AoA, right rudder is required to counter the prop effects, but at cruise and higher speed lower power regimes, the asymmetric vertical fin airfoil and the aileron and rudder trim tabs over-compensate and the left tendencies turn to right tendencies, requiring left rudder... Since most of the time the flights were performed under that regime, the stress on the left leg could become significant for 109 pilots...

As I read from rw pilot notes, at higher speeds / dives, a good deal of left rudder was required, to the point of the saying that "109 pilots were chosen among those with a longer left leg ..." :-)

The 109 doesn't have inflight adjustable rudder trim - just stabilator. Ground adjustable rudder and aileron trim tabs can be tuned in the "Special" options of the module. The elevator trim tab, which is also ground adjustable IRL, is not adjustable in any way in DCS (probably due to flight model limitations )

Beware that DCS also models very low temperature effects ( Winter scenarios ) of the geopotential height, so that for the exact same QNH, in cold Winter days you'll be ( MAGL ) lower than on a corresponding situation in Summer time!