Me109 question: would tail planes be angled up / down when at rest?

[nmayhew]

Hi,

 

I am labouring through Eduard's 109 E-1 kit and want to know if when "at rest" the tail planes could be angled either up or down, and if so by how much?

 

given these pieces are supplied separately in the kit, i thought i might as well show them at an angle, if appropriate.

 

i would be grateful if anyone could illustrate with pics if possible.

 

finally, would the tail plane angle be linked to anything else? just so i don't have an unlikely or impossible configuration...

 

many thanks,

 

Nick

[LSP_Ron]

Slightly up or slightly down would be perfectly acceptable Nick

 

 

 

[nmayhew]

Ron,

 

thank you kindly - niiiice pics!

 

both the first and last pics lead me to another related question:

 

what about the ailerons?

 

would they both droop down, maybe at same angle of the flaps, or is it a case of one up, one down?

 

cheers,

 

Nick

[LSP_Ron]

Always one up one down or neutral, never both drooping down like flaps for flaperons

 

Cheers

[Allok]

Don't forget, if you model the elevators in the down position, the tail wheel needs to be straight. I you want to have the tail wheel in a slightly turned position the elevators will have to be in the full-up position.

I believe this feature was the same on the 190s too.

[LSP_Ron]

Don't forget, if you model the elevators in the down position, the tail wheel needs to be straight. I you want to have the tail wheel in a slightly turned position the elevators will have to be in the full-up position.

I believe this feature was the same on the 190s too.

 

That's a new one to me?

[Sabre F-86]

That's a new one to me?

 

 

Yeh, first I've ever heard of that one too.

 

Sabre

[Sabre F-86]

I'm thinking that bit of info is incorrect. Im looking at several photos now where the elevators are neutral or down and the tail wheel is turned off axis.

 

Augsberg Eagles, page 67, 109E-4 WN 1361, neutral with wheel set for a hard port turn.

 

same page 84, 109G-2 markings DN+Y0 parked with elevators down,wheel completely reversed.

 

same page 89, 109G-6 british capture WN412951 neutral with wheel set for hard port turn

 

Messerschmidt bf-109 b/e japanese book. page 146 109E-3 elevators down wheel set for gentle turn to port

 

Aircraft monograph 18 Me109 pg 45 109E-3 wn4101, parked elevators down, wheel completely reversed.

 

Same pg 48 109E-3 Russian purchase, elevators down, wheel set sideways.

 

 

I can't find any documention concerning an interlock on the tail wheel that would require it to be full up elevator to turn the wheel. It makes sense that when taxiing the elevators are full up to keep the tail on the ground but as far as I can tell the tail wheel was free to turn when ever it liked, full castor.

 

Sabre

[ChrisS]

Always one up one down or neutral, never both drooping down like flaps for flaperons

 

Cheers

 

But and however...when the 109s flaps are down, BOTH ailerons droop. They still function independantly, but this feature allows the ailerons to function at full effectiveness while the boundry air layer moves back and under the wing leading edge as the flaps alter the angle of attack. It's a total nerd fact, but true none the less. Most folks would not notice this so as you toss this into into the bin, add a dash of salt to it

[LSP_Ron]

But and however...when the 109s flaps are down, BOTH ailerons droop. They still function independantly, but this feature allows the ailerons to function at full effectiveness while the boundry air layer moves back and under the wing leading edge as the flaps alter the angle of attack. It's a total nerd fact, but true none the less. Most folks would not notice this so as you toss this into into the bin, add a dash of salt to it

 

Interesting, I didn't know the 109 did that

[Allok]

I'm thinking that bit of info is incorrect. Im looking at several photos now where the elevators are neutral or down and the tail wheel is turned off axis.

I can't find any documention concerning an interlock on the tail wheel that would require it to be full up elevator to turn the wheel. It makes sense that when taxiing the elevators are full up to keep the tail on the ground but as far as I can tell the tail wheel was free to turn when ever it liked, full castor.

 

Sabre

Ooops... seem to have put my foot in it, and I can't even back it up because I can't remember where I read it!

Now I'm starting to think the opposite is actually true with the tail wheel being locked with the stick pulled hard back. (like the Focke Wulf and the Mustang)

I am seeing a lot of pics on the net of 109s with the elevators in the full-up position, particularly while they are being worked on or manuvered.

 

Sorry about the misinformation.

[nmayhew]

cheers guys

 

very interesting stuff

 

i guess i will go with flaps down, and both ailerons down as well (this is i think indicated in the kit, but it's good to have it backed up!)

 

i'll update my build later today

 

thanks again

 

Nick

[LSP_Ron]

cheers guys

 

very interesting stuff

 

i guess i will go with flaps down, and both ailerons down as well (this is i think indicated in the kit, but it's good to have it backed up!)

 

i'll update my build later today

 

thanks again

 

Nick

I'd hold off with positioning both ailerons down. What Chris says may very well be true but I would still question seeing a kit with the ailerons positioned this way. I think I would want photo evidence before I modeled them in that position. I can't find a single photo anywhere that conclusively shows them in that position nor have I heard of any WW2 prop aircraft possessing such a feature as ailerons dropping with flaps. I found this picture,

 

 

Flaps partially down with ailerons neutral but it is not an "E"

 

I know this wasn't a feature on the G model or at least one that automatically happened when the flaps were dropped. I took this photo in Hendon and there are plenty on line that show them with full flaps and neutral ailerons.

 

 

Was this a feature only on the E model or was it on all of them but could only be selected by the pilot i.e. they didn't automatically drop with the flaps?

[ChrisS]

When I was making (sim) aircraft for this game www.wwiionline.com we had tons of factory documentation on the 109 (and yes this was for the E4) that stated the aileron droop. I'll dig around and see if I still have any of that stuff.

[Juggernut]

The only way the elevators could be up when the aircraft is parked is if there was a gust lock of some type installed to keep the controls from being blown around by the wind. This would mean the stick was pulled back. I don't know if the 109 had any kind of a mechanical lock mechanism (such as a pin or a clamp), but if not it would most likely have been done by looping a seat belt around the stick, pulling it backward toward the seat. This is what's commonly done on many light aircraft that have sticks (we do it on all of the gliders at our club all the time). That also has the effect of using the wind to keep the tail on the ground. I've seen tail dragger airplanes get their tails lifted right off the ground by a good gust of wind.

 

Ailerons would only be deflected if the stick were moved to one side or the other. Remember if you're going to deflect the ailerons on almost any aircraft you can name, the down going aileron deflects less than the up going aileron. This is to counteract adverse yaw induced by the extra lift the down going aileron creates. I can't think of an airplane later than about 1910 that didn't have this feature built in.

 

I've never heard of aileron droop on the 109. Not saying it didn't happen, but I've been studying 109s for many, many years, and I've never heard of that feature. There is no need to alter aileron function as a result of changing the angle of attack on any airplane. On an aircraft such as the 109 (that doesn't to my knowledge have a computer on it), there would be no way to rig it so the airplane would "know" what its angle of attack was, and thus how much (if at all) to droop the ailerons in the first place. In any event, it wouldn't do anything anyway, since there is still the exact same airflow over the wings regardless of angle of attack. The only time that changes is in the stall, when the airflow detaches from the upper surface of the wing and (assuming that part of the wing is stalled) the ailerons become ineffective completely. This is why wings are designed so that they stall from the root out toward the tip. That maintains aileron effectiveness longer, and is safer, since the pilot has lateral control during the stall.

 

As for the tail wheel, it has no connection whatsoever to the elevators (on any airplane ever made). The tailwheel on the 109 was, as far as I'm aware, free castoring. It would align itself to whatever direction it was moving when it stopped. On some a/c there is a connection between the rudder and the tail wheel, but I don't believe it did on the 109.

 

J

 

 

Ever see a hangared Falconjet (F20F) come off a set of jacks due to a wind gust? I have...and the wind gust was not a hurricane gust either (probably about 40mph). Lifted one wing clear off the jack and thankfully dropped it back on the jackpad but not exactly where it came off...talk about sweating when taking the plane off the jacks immediately thereafter (with the hangar doors closed).

 

The aileron's you're referring to are called differential ailerons. There is another design used to counter the adverse yaw called Friese type ailerons (spelling). These ailerons, you've probably seen them, have a hinge line that's set back from the leading edge more so than normal. The idea is that the leading edge of the upward swinging aileron protrudes into the airstream across the underside of the wing creating drag and negating the increased lift generated by the higher wing. That "twist" you refer to in making the wing stall from root to tip is called washout. Not every aircraft his it. I am not aware of any of the WWII aircraft that had it built in but I haven't studied the engineering drawings of most of these aircraft, so it might indeed be part of every aicraft of that era, I've just not noticed it. The Corsair used a stall strip to keep the wings level during a stall on the -1A and later.

 

The F6F Hellcat did have ailerons linked to the flaps in that when the flaps were down, the ailerons drooped equally on both sides limiting the allowable roll and giving some additional lift at low airspeeds and preventing overcontrolling during high AoA approaches. I'm a bit curious about your choice of words when desribing the airflow over a stalling wing. The word "detaches" doesn't immediately leap to mind but I suppose it gets the point across. I would've described it a little differently but that's just me. In effect, the wing stops flying.

 

As far as the position of the elevators when the aircraft is at rest.... Control surfaces are balanced about their focal points (hinge lines) and depending on the balance requirements from the manufacturer, that balance, when installed, may be nose heavy, tail heavy or neutral. Notwithstanding friction in the control system, the elevators will return to their balanced (or imbalanced) state. That means if the elevators are balanced nose heavy, they will tend to rotate up if left alone on the ground (again, friction in the control system negated) and vice versa. If they're balanced to be neutral when on the aircraft then they will tend to seek a trail position as their at rest state or slightly up on a conventional aircraft (aka tail dragger). Taking friction into account and depending upon the amount inherent in the system, it might be enough to keep the elevators in whatever position the control stick is left in.