BF109 Ruder trim?

Marcel · 10-13-2007, 12:43 PM

Last week when I was at the RAF museum in Hendon, I saw a BF109G. Looking at the tailplane I wondered, where's the ruddertrim? See the picture below.
Usually you can see those little ruders in the vertical rudder but not on this one. Did I miss it somewhere? Was it normal on a Bf109 to not have a ruder trim? If so, had they other means of directional trim?

FLYBOYJ · 10-13-2007, 01:06 PM

Was that a G-2? I've seen several photos of G-2s without rudder trim.

Marcel · 10-13-2007, 01:12 PM

yep a G-2

Wurger · 10-13-2007, 01:29 PM

It is true.The F and G ( especially early Gs) didn't have a rudder trimtabs.It depended on the kind of fin and rudder which was mounted to the fuselage.

pbfoot · 10-13-2007, 01:36 PM

heres the E4 and it has a piece of flexible metal which is the red piece

Wurger · 10-13-2007, 01:51 PM

It is a common way for Bf 109 to balance the rudder.

Downwind.Maddl-Land · 10-13-2007, 02:08 PM

Unlikely as it seems, the Bf-109 didn’t have any adjustable rudder trim. As Capt Eric “Winkle” Brown records of the ‘109G in his series ‘Viewed from the Cockpit’:

“A shortcoming was the lack of any rudder trimming device. This meant that is was necessary to apply moderate right rudder during the climb and considerable left rudder during a dive. Thus, although the Bf-109G pilots tended to bunt into a steep dive as an escape manoeuvre in dogfights, they had some very heavy rudder and elevator control forces to contend with as speed built up and pull-outs at low level had to be made with considerable circumspection.”

The red trim tab on PB’s photo of the ‘109E looks like a fixed tab that would have been set, after much trial and error and numerous test flights, by the ground crew as the best compromise over the aircraft’s performance range.

Marcel · 10-13-2007, 02:08 PM

So the flexible metal is used as trim then? Could it be operated from the cockpit?

Marcel · 10-13-2007, 02:13 PM

ha clashed posts. So you think this piece of metal was only used to couter the plane's natural directional instability?

Downwind.Maddl-Land · 10-13-2007, 02:18 PM

Yep, that's about it. Use it to take out the individual airframe manufacture error and presumably set it for most comfortable cruise position......

However, following on from Wurger's comment above, I have just found a cutaway drawing of a G-14 with the bigger wooden fin and rudder that shows a 'Geared Rudder Tab' so it looks as though the issue was addressed later in the conflict

pbfoot · 10-13-2007, 02:24 PM

Quote:

Originally Posted by Marcel

So the flexible metal is used as trim then? Could it be operated from the cockpit?

not a chance I'm assuming its flexible but am not going to pull on it to try. i would guess one or two flights would set it up. Maybe some one can translate the word after Nicht

Marcel · 10-13-2007, 02:38 PM

Nicht anfassen= don't touch.

Wurger · 10-13-2007, 03:04 PM

Exactly.

Marcel · 10-13-2007, 03:09 PM

Quote:

Originally Posted by Downwind.Maddl-Land

Yep, that's about it. Use it to take out the individual airframe manufacture error and presumably set it for most comfortable cruise position......

However, following on from Wurger's comment above, I have just found a cutaway drawing of a G-14 with the bigger wooden fin and rudder that shows a 'Geared Rudder Tab' so it looks as though the issue was addressed later in the conflict

That's quite late, isn't it? I mean, most planes at that time had these trim surfaces. Why on earth didn't they put one on the Bf109 in the first place. I mean must have been quite a starin on the pilot with the big engines at all.

Downwind.Maddl-Land · 10-13-2007, 03:14 PM

Quote:

I mean must have been quite a strain on the pilot with the big engines at all.

Check out the accident rate of 109G's and you'll see how right you are! Bit of a bu**er on landing I understand.........