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View Full Version : why not a adjustable in cockpit rudder trim in the 109?



stalkervision
06-20-2008, 07:18 PM
People were and are still always finding fault in this lack of trim feature in the 109 but I have never ever read about any german pilots complain about it? It could have been easily corrected in the 109 line of aircraft certainly.

what gives? http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif

Kettenhunde
06-20-2008, 07:34 PM
Hi Stalkervision,

Two quick points:

1. The Bf-109 had rudder trim. It was fixed tab. This fixed tab saves considerable weight when compared to the mechanical linkage and differential of an adjustable tab.

2. As a pilot and owner of an aircraft that has rudder trim, it is over-rated IMHO. I very rarely use it.

All the best,

Crumpp

stalkervision
06-20-2008, 08:05 PM
Thanks for the nice personal insights Kettenhunde. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif I know about the outside adjustable tab and also the fact that the 109 has a rudder that is made with built in trim for flying at it's best crusing speed. There always seems to be some negative bias in all non=german 109 testors that I have read about this lack of feature. Seems they are really bothered and concerned with it's max speed prop torque factor.

Kurfurst__
06-20-2008, 10:33 PM
German specifications at the time did not require rudder trimmer to be fitted to aircraft under 5 tons takeoff weight.

Tab_Flettner
06-20-2008, 10:44 PM
What was the fixed tab called?

RAF_OldBuzzard
06-21-2008, 10:32 AM
One thing to consider is that the 109 didn't have much in the way of range. It's combat radius was something on the order of 125 miles. Short range=less time in the air=less problem of fatigue caused by holding rudder with legs.

The US fighters had much more range, and pilots were in the cockpit for much longer stretches of time. Having adjustable trim for multiple axis meant that they were a little less fatigued by the time they got to combat. I know it doesn't sound like much, but it could make a difference in a pilots combat efectiveness, and that little "edge" may have been what kept some guys alive.


Originally posted by Tab_Flettner:
What was the fixed tab called?

We called the one on my Cessna 140 a "trim tab" http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Xiolablu3
06-21-2008, 11:39 AM
It seemed to be one of the big things that Allied pilots flying the 109 complained about.

However German pilots barely seem to mention it.

I have seen some joking comments from the German side, that you could tell a German fighter pilot because his right leg had more muscle that the other, from pushing constantly on the rudder.

I guess its not too much of a problem unless you are flying for 4 hours in a Reconassance 109, then it might get to be an annoyance.

Mark Hanna flying the 109 :-

'The speed has picked up to the 109's cruise of about 400km/h, and now the ball is right in the middle, and no rudder input is necessary.'

Wildnoob
06-21-2008, 12:06 PM
Originally posted by Kettenhunde:
2. As a pilot and owner of an aircraft that has rudder trim, it is over-rated IMHO. I very rarely use it.

same for me, but I'm not a pilot and never flew any aircraft.

this with me can be apply with all aircraft on this sim until a problem appear.

it's rare I use the BF-109, but just get it now to do a test with wat should be a massive torque that began to appear a few months ago. it started to fall from the rigth very quickly, even if I was making pressure to the left to try counter it. in few seconds it fell many degrees to the rigth.

even if I turne the torque off, the same behavior remain.

before this started to happen, my fligths where like the real ones of Kettenhunde, it was not needed to adjust rudder trim. the fact is, even adjusting rudder trim with the aircraft wich have this feature, the problem is not solved and all the planes remain banking to the rigth.

I just can say it's a agony to see the plane falling out of course and could do nothing.

please, anyone here can tell me a site where I can host a video for download without need the creation of a acount ?

I want post a video of the problems I cited above, a video of a aircraft actually falling out of course to see the opinion of the members about it.

mortoma
06-22-2008, 09:16 AM
Originally posted by Kettenhunde:
Hi Stalkervision,

Two quick points:

1. The Bf-109 had rudder trim. It was fixed tab. This fixed tab saves considerable weight when compared to the mechanical linkage and differential of an adjustable tab.

2. As a pilot and owner of an aircraft that has rudder trim, it is over-rated IMHO. I very rarely use it.

All the best,

Crumpp If you owned and flew a WWII type fighter, with far more torque than your easy to fly GA aircraft, you'd used rudder trim if you had it. Believe me. Big difference between an old fighter and a newer GA aircraft. If you're really a owner/operator, you should know that. Shame on you.

K_Freddie
06-22-2008, 02:32 PM
In the game I find myself using it all the time, and it does 'zero' at cruise speed ~ 390Kph AFAIK
But it's easier to use as an 'arm-chair pilot'... my legs still look sexy and balanced http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Kurfurst__
06-22-2008, 03:42 PM
Originally posted by mortoma:
If you owned and flew a WWII type fighter, with far more torque than your easy to fly GA aircraft, you'd used rudder trim if you had it.

Uhm, actually his group is restoring one currently..


Believe me. Big difference between an old fighter and a newer GA aircraft. If you're really a owner/operator, you should know that. Shame on you.

Let me guess - people nowadays posting on a discussion board with no actual flight experience at all know it all better than top designers, test pilots and air force officials of the 1940s who made decision about wheter trimmable rudder is a neccessity for single engined interceptors or not..

Xiolablu3
06-22-2008, 04:35 PM
SOme top test pilots actually did say that it was a shortcoming...


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."


Mark Hanna says it is not a problem for display flying...

"The rudder is effective and of medium feel up to 500km/h. It becomes heavier above this speed, but regardless, the lack of rudder trim is not a problem for the type of operations we carry out with this airplane.

Initial acceleration is rapid up to about 560km/h-particularly with nose down. After that, the 109 starts to become a little reluctant, and you have to be fairly determined to get over 600 km/h"


I guess it all depends on what the pilot is used to.

Like Gunther Rall says, one feels at home in a plane that one has flown for years.

BTW: I found a statement by someone that the 109F and G2 didnt even have the adjustable tab which could be changed on the ground. I find this very difficult to believe. Can you shed any light on this Kurfy?

ElAurens
06-22-2008, 04:45 PM
I agree with you Kurfy.

http://forums.ubi.com/groupee_common/emoticons/icon_eek.gif

But on that same note, no one on this board will take the word of a current pilot of a P51 that our version is incorrect on many levels.

So where does that leave us?

julian265
06-22-2008, 05:44 PM
Real 109 pilots would have been required to fly over much more varying speeds, altitudes and attitudes than the average GA pilot, making rudder trim a more attractive feature.

How is having rudder trim a draw back? Its exclusion doesn't even save considerable resources.

There have been enough comments by people who flew the 109, mentioning it's high rudder forces, and effort required when in a dive, to make me believe that it would have been better with rudder trim.

Kurfurst, whilst I agree with your "internet expert" point, just because a designer made it so, doesn't ensure that it was the right decision. People say that regarding cars and modification quite a lot, yet the car designers forget and reinvent the wheel with each new model.

luftluuver
06-22-2008, 07:34 PM
Originally posted by Xiolablu3:
BTW: I found a statement by someone that the 109F and G2 didnt even have the adjustable tab which could be changed on the ground. I find this very difficult to believe. Can you shed any light on this Kurfy?

Xio, there was a tab but it did not stick out like on later models. It is just above the tail light. If you look at profiles you will also see that the rudders had a counter balance portion which was lost on later 109s when the line between the rudder and fin went straight.

luftluuver
06-22-2008, 08:55 PM
I don't know how anyone can compare flying a puny 100-150hp GA a/c designed for stability spinning a toothpick 2 or 3 bladed prop to a fire breathing 1600hp+ monster designed to be somewhat unstable spinning a 3 or 4 club bladed prop?

Kettenhunde
06-23-2008, 04:28 PM
I don't know how anyone can compare flying a puny 100-150hp GA a/c designed for stability spinning a toothpick 2 or 3 bladed prop to a fire breathing 1600hp+ monster designed to be somewhat unstable spinning a 3 or 4 club bladed prop?


Want to tell them what you learned today about airplanes?

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

luftluuver
06-23-2008, 04:51 PM
Originally posted by Kettenhunde:
Want to tell them what you learned today about airplanes?

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

I learned that military training a/c are considered GA a/c. But then using your criteria, the P-51, F4U, Spitfire and other military a/c flown by civilians are also considered GA a/c.

Taylortony
06-23-2008, 05:31 PM
Originally posted by luftluuver:

I learned that military training a/c are considered GA a/c. But then using your criteria, the P-51, F4U, Spitfire and other military a/c flown by civilians are also considered GA a/c.

Tell that to your insurance company and stand by to get laughed out of the room.....


Ahh I do love it when all the "experts" come out of the woodwork on issues of trim etc who's closest to a warbird, flying it or operating it is a game and they suddenly are experts on the subject as pointed out by kurfurst over the designers of the Aircraft...... Spot on Kurfurst.

Do you know how you adjust the aileron trim on a metal aileroned Spitfire? you take a block and hammer or pliers and literally bend the trailing edge of the aileron down until it flys level.. find that on the web...

Do you know where the word to TRIM an aircraft actually comes from? it was originally a piece of cord doped to the trailing edge of a control surface to give it weight to deflect it down and was "trimmed" by cutting sections off with a pair of scissors...........


Ahhh sometimes I just have to laugh when I read some of the posts on here

Kettenhunde
06-23-2008, 06:10 PM
Tell that to your insurance company and stand by to get laughed out of the room.....



I do tell that to my insurance company. Just like everyone else flying a Warbird in the United States they just write a policy and take your check.

They might put some requirements on you like flight time with an instructor or flight under certain conditions until you reach a specific number of hours.

http://registry.faa.gov/aircraftinquiry/acftinqSQL.asp?...d.x=10&cmndfind.y=11 (http://registry.faa.gov/aircraftinquiry/acftinqSQL.asp?striptxt=P51&mfrtxt=North+American&modeltxt=P-51&cmndfind.x=10&cmndfind.y=11)

All the best,

Crumpp

Kettenhunde
06-23-2008, 06:18 PM
Ahhh sometimes I just have to laugh when I read some of the posts on here


No doubt.


Luftluver says:
I don't know how anyone can compare flying a puny 100-150hp GA a/c designed for stability spinning a toothpick 2 or 3 bladed prop to a fire breathing 1600hp+ monster designed to be somewhat unstable spinning a 3 or 4 club bladed prop?


We can compare them or transfer experience because all aircraft fly by the same principles and physics.

Understand?

The difference is the forces involved which tends to speed the rate at which things go bad. In fact if you look at trainers, most of them have worse characteristics than the aircraft they are designed to prepare the student pilot for flying. Great example of this is the Piper Tomahawk or the T-6 Texan.


Another characteristic of the Piper Tomahawk that favors its suitability as a primary trainer is that the flight control forces mimic those of a much heavier aircraft. As a result, student pilots that learn to fly in a Tomahawk transition much more successfully to larger aircraft, hence the popularity of the Tomahawk with U.S. Air Force flying clubs.



http://en.wikipedia.org/wiki/Piper_PA-38_Tomahawk


The airplane is harder to fly than a P-51. I've flown both now, and I never would have never thought that was true. Understand, it's nothing a competent pilot can't handle, but the aircraft is the consummate trainer; she demands constant attention to be flown well just like the T-38 did.



http://www.warbirdalley.com/articles/T6-sf.htm

So now you know how we can compare a puny 150 hp GA aircraft to a 1600hp fire breathing monster.

It is your perception of airplanes that needs adjustment.

We could very well be talking about a 1600hp pussycat and a 150 hp fire breathing monster!


All the best,

Crumpp

Kettenhunde
06-23-2008, 06:22 PM
http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/693...681056866#2681056866 (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/6931023866?r=2681056866#2681056866)

Taylortony
06-23-2008, 06:23 PM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Tell that to your insurance company and stand by to get laughed out of the room.....



I do tell that to my insurance company. Just like everyone else flying a Warbird in the United States they just write a policy and take your check.

They might put some requirements on you like flight time with an instructor or flight under certain conditions until you reach a specific number of hours.

http://registry.faa.gov/aircraftinquiry/acftinqSQL.asp?...d.x=10&cmndfind.y=11 (http://registry.faa.gov/aircraftinquiry/acftinqSQL.asp?striptxt=P51&mfrtxt=North+American&modeltxt=P-51&cmndfind.x=10&cmndfind.y=11)

All the best,

Crumpp </div></BLOCKQUOTE>

I take it you buy it in blocks of Hours? The Spit here does, I seem to remember they but it in 25 Hour blocks, mind you it is for Air display purposes so that racks the cost up as well.

Kettenhunde
06-23-2008, 06:55 PM
I take it you buy it in blocks of Hours?


We go by the year over here for flight, taxi and/or ground Hull. Liability is different and has several options. I have full hull on all the flying planes and just ground hull on the others.

I have never asked if we can purchase in hourly blocks for liability. AFAIK we only get it in yearly contracts with no hourly limit. Once a year and paid in full is how aircraft insurance works in the US.

For shows there are other requirements and it might be in blocks. We are still a couple of years from that point though.


racks the cost up as well.

There is nothing cheap and no profit to be made in Warbirds. It is a big black hole with an insatiable appetite for cash.

All the best,

Crumpp

Taylortony
06-23-2008, 06:58 PM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I take it you buy it in blocks of Hours?


We go by the year over here for flight, taxi and/or ground Hull. Liability is different and has several options. I have full hull on all the flying planes and just ground hull on the others.

I have never asked if we can purchase in hourly blocks for liability. AFAIK we only get it in yearly contracts with no hourly limit. Once a year and paid in full is how aircraft insurance works in the US.

For shows there are other requirements and it might be in blocks. We are still a couple of years from that point though.

All the best,

Crumpp </div></BLOCKQUOTE>

Oh the hull is insured etc, its just they purchase the flying by the hour in blocks.. suppose its cheaper that way, a bit like you can insure collectors cars for so many miles per year.

Kettenhunde
06-23-2008, 07:04 PM
Oh the hull is insured etc, its just they purchase the flying by the hour in blocks.. suppose its cheaper that way, a bit like you can insure collectors cars for so many miles per year.

That would be the way to go.

I will check with our underwriter but it has never been offered as an option.

All the best,

Crumpp

leitmotiv
06-23-2008, 07:46 PM
Originally posted by Kettenhunde:
Hi Stalkervision,

Two quick points:

1. The Bf-109 had rudder trim. It was fixed tab. This fixed tab saves considerable weight when compared to the mechanical linkage and differential of an adjustable tab.

2. As a pilot and owner of an aircraft that has rudder trim, it is over-rated IMHO. I very rarely use it.

All the best,

Crumpp

To bolster your point, Crumpp, I know an ex-WWII Hellcat pilot. He said the only time he ever used his trim tabs was when he had to fly long cross-country flights over the USA. He never used them in the Pacific when flying off his carrier---kept them in neutral all the time. In this game, I use elevator trim, if I have it, and, rarely, rudder trim. I find it hilarious to read posts on this forum about trimming constantly in the middle of a mele.

The very late 109s with the tall wooden tails like the G-10, G-14, and K-4 did have in-flight adjustable rudder trim tabs.

julian265
06-24-2008, 02:17 AM
Oh! So now the designers-who-know-all DID add in flight rudder trim to the 109, despite the posters-who-know-all saying it wasn't needed.

hehe.

Kettenhunde
06-24-2008, 04:26 AM
Oh! So now the designers-who-know-all DID add in flight rudder trim to the 109, despite the posters-who-know-all saying it wasn't needed.


I don't think the tab was a cockpit adjustable rudder trim.

It was an aerodynamic balance to compensate for the increase in control surface area.

Do you understand the difference?

All the best,

Crumpp

luftluuver
06-24-2008, 04:29 AM
Originally posted by leitmotiv:
The very late 109s with the tall wooden tails like the G-10, G-14, and K-4 did have in-flight adjustable rudder trim tabs.

No they didn't. They had a Flettner tab.

julian265
06-24-2008, 05:10 AM
Yes I do know the difference, however I was going off what Leitmotiv said.

Point conceded.

Kettenhunde
06-24-2008, 06:01 AM
To bolster your point, Crumpp, I know an ex-WWII Hellcat pilot. He said the only time he ever used his trim tabs was when he had to fly long cross-country flights over the USA.


That is when rudder trim has been most useful to me too.

If you have to make long duration flights on the same heading, rudder trim is nice to gain a few knots.

Remember that adding adjustable rudder trim to the aircraft means additional weight and complication of the design.

In WWII terms, rudder trim would have been a useful feature for escort fighters on deep penetration raids.

For the defending interceptors its utility would have been reduced to the point the additional weight and complication was not worth it.

All the best,

Crumpp

Kurfurst__
06-24-2008, 01:00 PM
Originally posted by leitmotiv:
The very late 109s with the tall wooden tails like the G-10, G-14, and K-4 did have in-flight adjustable rudder trim tabs.

Nope. The ones with the tall rudder unit (introduced somewhere around mid/late 1943 IIRC) still had a fixed, ground-adjustable rudder trim tab, and also a Flettner-tab on the rudder to reduce control forces on the rudder.

Some late production G-10/R6, K-4/R6 (bad wheater fighrer aircraft variant) had PKS autopilot which maintained the course via an autopilot adjusting the rudder angle though.

ElAurens
06-24-2008, 05:15 PM
Our BlitzPig real world flight instructor says the same, trim is for long flights.

My question now is how does this square with the sim, where trim is so critical for even the simplest maneuvers on some large, heavy, known to be stable aircraft (P51, F6F, F4U), yet has little effect on light nimble kites, (A6M, Spitfire, 109)?

Something does not make sense here.

squareusr
06-24-2008, 06:11 PM
Originally posted by ElAurens:
My question now is how does this square with the sim


I can guess at an answer to the question of why trim is important for so much more than just long flights in the sim: stick quality. Most of our sticks have only between 5 and 8 bits of actual resolution, which just isn't enough. If we compensate buy setting a resolution curve with a "zoom" area around the center we lose additional resolution if we have to hold the stick off-center to fly straight and level.

Finally, i'll attempt a guess at the other question, why it is more of a problem with the heavy birds: if you correct your central vector by hand instead of trim you will make small jerky movements because no hand is perfectly steady. A light and nimble plane will quickly adopt its movement vector to the new attitude, losing only little speed because it will only be badly aligned for short times. A heavy, "stable" plane will keep the misalignment between attitude and movement vector for a longer time, losing more speed.

ElAurens
06-24-2008, 07:28 PM
Interesting.

Great first post BTW.

leitmotiv
06-24-2008, 11:52 PM
Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by leitmotiv:
The very late 109s with the tall wooden tails like the G-10, G-14, and K-4 did have in-flight adjustable rudder trim tabs.

Nope. The ones with the tall rudder unit (introduced somewhere around mid/late 1943 IIRC) still had a fixed, ground-adjustable rudder trim tab, and also a Flettner-tab on the rudder to reduce control forces on the rudder.

Some late production G-10/R6, K-4/R6 (bad wheater fighrer aircraft variant) had PKS autopilot which maintained the course via an autopilot adjusting the rudder angle though. </div></BLOCKQUOTE>

Servo tab---I literally forgot all about them! http://forums.ubi.com/images/smilies/35.gif http://forums.ubi.com/images/smilies/53.gif http://forums.ubi.com/groupee_common/emoticons/icon_eek.gif

WTE_Galway
06-25-2008, 12:06 AM
A couple of related points ...

1. Before I got grounded by diabetes I spent a fair bit of time in GA aircraft and once you know an aircraft well you can tell when its not in co-ordinated flight by the feel of the stick, the lateral forces on your body (particularly if it gets too far out of whack) and most significantly by sound .. an aircraft that is yawing has a distinctively different sound. In the sim you need to look at slip indicator. This can be particularly frustrating when lining up an initial shot because if you are yawing your gunsight is not pointing where it should be, but in the sim you cant really tell without looking down at the instruments.

2. I have read a number of wartime accounts that suggest the Luftwaffe was quite fanatical about fitness and pilots spent a lot of downtime playing football and similar competitive sports designed to make them stronger and fitter for flight.

Wildnoob
06-25-2008, 02:26 PM
Originally posted by leitmotiv:
To bolster your point, Crumpp, I know an ex-WWII Hellcat pilot. He said the only time he ever used his trim tabs was when he had to fly long cross-country flights over the USA. He never used them in the Pacific when flying off his carrier---kept them in neutral all the time. In this game, I use elevator trim, if I have it, and, rarely, rudder trim. I find it hilarious to read posts on this forum about trimming constantly in the middle of a mele.

I also don't used rudder trim, but as most people here are tired do know by reading my posts that a problem beggin to happen and all aircraft started to fall out of course.

but the report of this Hellcat pilot is amazing. if it's in fact truth, Oleg commited a great mistake.

wat in fact I know is that more modern the aircraft, less trim it should need. I already read that the P-51 require less trim then the P-40 for example. and this is in RL.

I always thougth that trim was a feature to help the pilot, not vice versa. for example, adjust it when you gonna climb. compensate the damage in one wing using airelon or rudder, among other useful ways. but with me, it's just a agony.

stalkervision
06-28-2008, 05:11 PM
excellent info here boys. Much apperciated from you all.

http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif