Bf 109 takeoff problems

At every start with the Kurfürst I'm getting of the runway. Please give some tips for improvements:helpsmilie:

Training and pratice.

My technique:

Rads open

engine auto

MW-50 on

"slowly" full throttle

full right rudder with some brake

Full rudder and some slight touches on brake will keep you on RWY.

And tail wheel lock...

At every start with the Kurfürst I'm getting of the runway. Please give some tips for improvements:helpsmilie:

BEFORE the takeoff:

prop pitch set to 12o'clock and set to MANUAL

coolant flaps open and set to MANUAL

trim: at least in dcs, its more comfortable to have a fully nose down trim, so trimwheel all the way forward until you can read the 2 on the trimdisplay.

takeoff:

full right rudder even BEFORE you push the throttle forward.

throttle full forward, full power, then quickly slightly back, to not use MW50 at 1.8ata, but 1.4ata.

you might even need to touch the right brake briefly. in the very first part of your takeoff, it also helps to keep the stick slightly held to the right. (this is one thing i dont like in the dcs FM at all....ailerons are more effective at low speeds than the rudder. slight right aileron input acts like rudder in real life and keeps you straight)

the more you accelerate, the "less" rudder you will need(and with dcs physics, the less right aileron you will need)...but you will still need plenty and sometimes all the rudder you have. you dance on the rudder to keep her straight.

then there is the moment, where the tail comes up off the ground...its important, to have again full right rudder in that moment...its even better, if you do this in advance. better give full right rudder a second before the tail comes up. otherwise you are likely to tilt with one wing.

once the tail is up and you are running only on the mainwheels, keep your feet prepared to give left or right rudder inputs to keep the plane straight. at around 180-200kph, slightly pull on the stick to have a positive rate of climb.

i hope this post helps slightly more than the suggestion to just "practice" ;)

EDIT: the above is one way. and pretty close to how you would do it in a real 109. in dcs though, there are many different ways to do it... it is even possible to takeoff even without any rudder inputs at all...im sure thats not going to happen in any real life 109.

BEFORE the takeoff:

prop pitch set to 12o'clock and set to MANUAL

coolant flaps open and set to MANUAL

trim: at least in dcs, its more comfortable to have a fully nose down trim, so trimwheel all the way forward until you can read the 2 on the trimdisplay.

 

takeoff:

 

 

full right rudder even BEFORE you push the throttle forward.

throttle full forward, full power, then quickly slightly back, to not use MW50 at 1.8ata, but 1.4ata.

you might even need to touch the right brake briefly. in the very first part of your takeoff, it also helps to keep the stick slightly held to the right. (this is one thing i dont like in the dcs FM at all....ailerons are more effective at low speeds than the rudder. slight right aileron input acts like rudder in real life and keeps you straight)

 

the more you accelerate, the "less" rudder you will need(and with dcs physics, the less right aileron you will need)...but you will still need plenty and sometimes all the rudder you have. you dance on the rudder to keep her straight.

 

then there is the moment, where the tail comes up off the ground...its important, to have again full right rudder in that moment...its even better, if you do this in advance. better give full right rudder a second before the tail comes up. otherwise you are likely to tilt with one wing.

 

once the tail is up and you are running only on the mainwheels, keep your feet prepared to give left or right rudder inputs to keep the plane straight. at around 180-200kph, slightly pull on the stick to have a positive rate of climb.

 

 

i hope this post helps slightly more than the suggestion to just "practice" ;)

 

EDIT: the above is one way. and pretty close to how you would do it in a real 109. in dcs though, there are many different ways to do it... it is even possible to takeoff even without any rudder inputs at all...im sure thats not going to happen in any real life 109.

Thank you, with this technique it works :D

take off

i do exactly the same prop 12 o'clock flaps 20 degree radiator open only difrence its i set 1.3 ata max for take off it's more the enought

I must say, that I agree with the most of advices you gave... but the statements above can not be accepted as right ones. First of all, in real world ailerons have no authority more than rudder. If rudder already has more authority at stall speeds both in yaw (of course!) and in roll because of significant adverse yaw effect of ailerons. As CPSU always taught us, the effect of aerodynamic forces depends on speed in second power, so at speed of TO start their effect are very low and sometimes can be even adverse.

And I desperately want to see video of 109's takeoff without rudder input... With ctrl-enter window on. :)

 

 

if im not mistaken such a video already exists in the groundphysics thread.

and i completely agree with your statements about the real life behaviour of ailerons and rudder...

but i just cannot observe them that way in dcs.

especially in the 109, in vertical manouvers at stall speeds, its the rudder that all of a sudden seems to cause adverse yaw effects and not the ailerons.

with this statement i dont mean that adverse yaw is not modeled for ailerons,

(i know it is modeled)

but just that its definitely easier to climb higher before stalling when using the ailerons to keep the plane on the vertical path instead of trying to adjust with rudder...especially in the period close before the stall happens...this doesnt mean i am of the opinion that in dcs no rudder is needed at all though either. you will still need right rudder.

but its better to just give little right rudder at the start of your vertical manouver, and then dont move it anymore until the stall happens(even if the slipball shows drastical slip). and avoid the stall as long as possible with the ailerons. this might be connected with my previous observation, confirmed by others who tested this as well, that slight to medium slips dont seem to cause any drag at all. but thats an assumption on my part that there is a direct connection with the above.

i know this thing has slats which keeps the ailerons longer effective than without..but still.

i can also observe, that on the ground on takeoff, right ailerons all of a sudden keep the nose from drifting the the left, where even full right rudder doesnt do its job.(in dcs of course, not in real life)

these are my personal observations in dcs, flying the 109 since its beta release.

And I desperately want to see video of 109's takeoff without rudder input... With ctrl-enter window on. :)

Not the most beautiful takeoff, but without rudder input and unlocked tail wheel.

Not the most beautiful takeoff, but without rudder input and unlocked tail wheel.

 

 

Easy peasy :)

Easy peasy :)

Wow. Just... wow.

I know it's stupid of me to ask, but certainly no training wheels (game mode etc.) on? Now I have to confess having no real flight experience in the 109 - I've bought it and have test flown it a couple of times in an earlier version of the sim, but that's all - but I've got plenty of hours in the Mustang; and regardless of any possible ground physics changes, I absolutely cannot take off in it without inputting some right rudder and aileron even in the latest Openbeta. So is this perhaps an aircraft-specific bug or something, because what's shown in this video has got NOTHING whatsoever to do with reality?

Every prop aircraft requires rudder and aileron input on takeoff and landing, this a because of engine torque. Sudden movements up or down cause a corresponding roll one way or the other. It's exaggerated with the 109 due to being small, high power, with a high and narrow wheelbase.

With the Mustang, you can power against the brakes to get control authority, this doesn't work with the 109, you start out using the brakes to control lateral movements, moving to rudder and aileron control as you gain speed. It also helps to apply some down elevator to keep the nose from pitching up as it takes off.

-note

I always disable flight aides. Against my religion.

Wow. Just... wow.

 

I know it's stupid of me to ask, but certainly no training wheels (game mode etc.) on?

No training wheels and full sim.

Rudder wasn't used, but toe brakes - right toe brakes - were... That explains why it worked, I guess ?

Actually, I have to say that DCS WW2 modules are the only reproductions of prop aircraft where I can feel the need to apply rudder, inflight, without having to look at the turn coordinator.

In combat the need for rudder input differs from module to module, but when required, you feel it naturally, and not by "being told"....

In other games, sometimes a whole lot of sideslip is being indicated by the turn coordinator, but without looking at it I wouldn't tell from the feedback of my virtual aircraft.

this a because of engine torque

Plus the prop causing a spiraling slipstream making its thrust asymmetrical. I know this, as do most folks having ever flown these birds, even virtually. It's why I was a bit bewildered by the video up there ;)

Never know, I was just offering my experience in.general not directed at anyone :p I did add the caveat that I play with flight aides off, which appeared to be enabled up there =)

Never know, I was just offering my experience in.general not directed at anyone I did add the caveat that I play with flight aides off, which appeared to be enabled up there =)

Aides off, and you could still maintain your heading with wheel brakes only, taking off with approx. 1.4 ATA on the MAP gauge it seemed. This can't be right...

OK, I'm stumped. Made a dummy test pilot, hopped into the Biffer, killed myself a couple of times before managing to survive a couple of hair-raising takeoffs on low ATA - and, surprisingly, survived the landings too (the landings are much easier, it seems). The engine torque is MURDEROUS and there's no way on earth I could've taken off with just wheel brakes, just wouldn't have been possible at all. You geezers sure your Biffer isn't broken somehow???

PS / EDIT: and, oh, how do you trim this deathtrap for takeoff, BTW? Nose down somewhat I presume?

EDIT2: those clowns claiming DCS has no torque modelled should have their heads amputated, end of. Because they clearly have no need for the appendage.

Aides off, and you could still maintain your heading with wheel brakes only, taking off with approx. 1.4 ATA on the MAP gauge it seemed. This can't be right...

If you look carefully he maintains 1,2 ATA until around 150km/h, which means that enough propwash has already developed, by that time, for the rudder trim tab to start doing it's job. Since a few versions ago the 109, as well as the 190 if I'm not wrong ( ? ) also allow for the setting of their ground trim tabs for rudder and aileron - we don't know if the video was recorded when this additional aid was already available, and that ground adjustable trim tab set considerably starboard ?

P.S.: Yet, I actually can't observe any rudder deflection even eventually induced by that rudder trim tab ...

The only thing that the DCS 109 does not have, probably due to a limitation in it's core FDM, is the chance for multiple ( more than two ) control compensators contributing to a control surface. Probably a maximum of two are allowed, and since in the 109 and the 190 there are actually 3 "pitch control contributors" - elevator, stabilator and elevator trim tab - only the first two can work. In another combat flight simulator that allows for all of the three, we have a fixed, set by the developers and not adjustable by the user, elevator trim tab, and as power is added during takeoff, one can see the elevator deflect ( down ) compensating for the pitching up tendencies of the K-4 with a filled MW50 tank ( although the weight of the MW50 tank is probably also well compensated by the heavier engine ? ).

Overall, I don't say DCS is perfect, of course it isn't for sure, but it is a very close approximation in many levels to the possible PC-based modelling of a prop aircraft, given the limitations imposed by a combat simulation game.

Some years ago I discussed in a thread started by me the fact that there was a weird effect noticeable on the P51d when taking off with the first point of flaps, full power and a good deal of crosswind. Instead of turning upwind the aircraft, at the beginning of the takeoff run, showed a tendency to yaw downwind, and the downwind wing a slight tendency to want to come up, resulting in the virtual pilot having to use at that phase rudder into and aileron away from the wind ?????? How was such effect possible ?

I found out later, and even sent Yo-Yo the document with the mathematical development, the "proof of concept", from an aerodynamics text book. The reason was, just as Yo-Yo pointed out on that thread, the fact that indeed the deflected propwash acting over the root of the downwind wing, and the downwind tail surfaces was enough to cause the additional lift, and associated drag as well as the asymmetric hit of tail surfaces, and the resulting downwind moments at that initial phase of the takeoff run...

So, I tend to accept, with due imitations of course, most of the outcomes I get from DCS aircraft I own ( only those by ED/Belsimtek, until the Christen becomes available :-) )

SORRY! Double post :-/

Did one more - taking off with ~1.2ata and manual pitch 12 o'clock

You can see my settings at the end of the video - no assists and trim tabs all set to 0

The faster you get the harder it is to keep it on track and obviously the takeoff isn´t that nice overall but still it´s possible without touching the pedals.

Since the last video I´ve also done a complete new installation of DCS on another hard drive so I don´t think anything is broken on my end.

@msalama

Yeah, trim nose heavy for takeoff - I prefer to trim it full nose heavy.

No, I believe you, the evidence is there so there's nothing to debate. I just wonder why it clearly cannot be done on my end is all... weird stuff :huh:

Probably a maximum of two are allowed

What makes you think so?