Bf-109 Landing gear

[Sternjaeger]

lol those were the days 

 

 

...uh and for the record... psssst, Crump, no shims on this one either!

Edited November 22, 2013 by Sternjaeger

[NZTyphoon]

lol those were the days 

 

 

...uh and for the record... psssst, Crump, no shims on this one either!

 

Gotta be shims on the sway brackets, otherwise the toilets trajectory would have been compromised (It wasn't flush fitting, anyway).

Edited November 22, 2013 by NZTyphoon

[Crump]

 

109K-4 Flugzeug Handbuch November 1944: Teil 2: Fahrwerke

 

 

You do realize that is not the maintenance manual?

 

I am perfectly happy to let you think it is and you have made some worthwhile point that adds greatly to the discussion.

[Sternjaeger]

You do realize that is not the maintenance manual?

 

I am perfectly happy to let you think it is and you have made some worthwhile point that adds greatly to the discussion.

 

"Rise and Shine" Crump   

 

Edited November 22, 2013 by Sternjaeger

[Crump]

You shim the Bf-109 gear at the torque link like most torque link equipped oleo's.

[Sternjaeger]

ah that's where you shim it now. Got a manual for that?

[Crump]

No I don't have a copy of the maintenance manual for the Bf-109 but I do know a mechanic who maintains one.  You shim the torque link like all torque link oleo's.

 

The number and thickness of the washer's going on the bolt at the torque link scissor determines adjustment of the wheel to roll straight. 

Typical torque link shim kit:

 

https://www.aircraftsupply.com/tl-shim-kt-1.html

[Bearcat]

Why is it that it is always the threads about German aircraft .. that always attract the same people and always denigrate into nonsense and multiple reports.

 

Why is that? Can somebody tell me?

[Crump]

They are all kinds or you can even fabricate them.  Part of the privileges of an A&P. 

 

http://www.skygeek.com/mcfarlane-aviation-mcs14506b14-007-faa-pma-torque-link-shim.html?utm_source=googlebase&utm_medium=shoppingengine&utm_content=mcfarlane-aviation-mcs14506b14-007-faa-pma-torque-link-shim&utm_campaign=froogle&gclid=CNaogvbN-boCFct9OgodCXQAaw

One thing about the German tires, they are not the greatest.  The Germans had serious issues with natural rubber and it was always in very short supply.  The canvas/rubber carcasses for the Continental tires were pretty thin.  In fact, it even warns in the manual not to make sharp turns as you can damage the tire.

[Crump]

I bet the Bf-109 manual is just as accurate!

 

 

 

http://www.amazon.com/Millennium-Falcon-Owners-Workshop-Manual/dp/0345533046/ref=pd_sim_b_5/180-0279270-8732830

[NZTyphoon]

Unofficial modification (Jager tragbare toilette or "thunderpot" http://www.dict.cc/?s=thunderpot), considered for carrier use and tested on a 109G-6/Abort

 

[Sternjaeger]

Why is it that it is always the threads about German aircraft .. that always attract the same people and always denigrate into nonsense and multiple reports.

 

Why is that? Can somebody tell me?

 

It's all in good jest, or so I thought? 

[Crump]

You really think so?

[Sternjaeger]

Crump, man, you're the one having an issue with this whole thing here I'm afraid, we're all trying to have a good time, crack a joke or two and perhaps also share some useful information, but as soon as you come up with some baloney of yours and someone dares contradicting you, you just start an endless tirade that often contradicts itself and/or ends up with the thread being locked, and if confronted in a constructive manner you just take evasive action.. How do you expect people to take you seriously? 

 

I don't know, I promised myself not to get into silly forum wars anymore, and I also enjoyed some of the stuff that you posted and agreed with you, but some other stuff, which has been repeatedly disputed by several real life pilots with larger experience than yours, is just conceptually wrong, and the last thing we need here is providing wrong information just because we need to defend our point.

 

Again, I'm trying to be constructive, so let's all make one big step back and try and change our approach to the whole thing, how's that for a plan? Other than for the fun and games, I think we can all objectively contribute to this community.

Edited November 23, 2013 by Sternjaeger

[NZTyphoon]

Crump, man, you're the one having an issue with this whole thing here I'm afraid, we're all trying to have a good time, crack a joke or two and perhaps also share some useful information, but as soon as you come up with some baloney of yours and someone dares contradicting you, you just start an endless tirade that often contradicts itself and/or ends up with the thread being locked, and if confronted in a constructive manner you just take evasive action.. How do you expect people to take you seriously? 

 

I don't know, I promised myself not to get into silly forum wars anymore, and I also enjoyed some of the stuff that you posted and agreed with you, but some other stuff, which has been repeatedly disputed by several real life pilots with larger experience than yours, is just conceptually wrong, and the last thing we need here is providing wrong information just because we need to defend our point.

 

Again, I'm trying to be constructive, so let's all make one big step back and try and change our approach to the whole thing, how's that for a plan? Other than for the fun and games, I think we can all objectively contribute to this community.

 

+1 150%

[Venturi]

Lim x->drama, f(x)=troll;

Lim x->info, f(x)=contributor

Edited November 23, 2013 by Venturi

[boot_Hardy]

Crump, man, you're the one having an issue with this whole thing here I'm afraid, we're all trying to have a good time, crack a joke or two and perhaps also share some useful information, but as soon as you come up with some baloney of yours and someone dares contradicting you, you just start an endless tirade that often contradicts itself and/or ends up with the thread being locked, and if confronted in a constructive manner you just take evasive action.. How do you expect people to take you seriously? 

 

I don't know, I promised myself not to get into silly forum wars anymore, and I also enjoyed some of the stuff that you posted and agreed with you, but some other stuff, which has been repeatedly disputed by several real life pilots with larger experience than yours, is just conceptually wrong, and the last thing we need here is providing wrong information just because we need to defend our point.

 

Again, I'm trying to be constructive, so let's all make one big step back and try and change our approach to the whole thing, how's that for a plan? Other than for the fun and games, I think we can all objectively contribute to this community.

Here's you answer, Bearcat.        This is how interesting threads become .. ehm... toilet.  

[LG1.Farber]

I didn’t mis-quote anything. The quote is exact, word-by-word.

I did not mean YOU misquoted.  I ment either Meyer was misquoted by the publisher or Meyer misquoted Steinhoff.

 

No I don't have the figures, I doubt they have been cataloged.  - Shame.  Although if this was true, all the Luftwaffe pilots books would be full of tales of landing and take off accidents.  For not every landing and take off accident resulted in a destroyed aircraft so if the figures are correct they must have accidents all the time.  However the Luftwaffe pilot books are not so full of these incidents.

 

We could debate until Christmas but for what? - Lets put it to bed.

 

S!

 

[Bulkhead]

Wow, my first post and I was stupid enough to think I started something that could be interesting. The myth about the 109's special landing gear and it's ground handling. I was hoping some discussion and thought about this and maybe some info on how this is being thought of in the sim itself. Hopefully a comment from a developer. The reason for the difficult handling is many, not just the angled legs. inexperienced pilot is also a reason. 

This thread was obviously a big mistake. Believe me when I say I know how to use a toilet. I use it every day, sometimes I dump my waste from both ends. I don't need a crap manual.

 

Kelli out.

Cheers

[Furio]

 

We could debate until Christmas but for what? - Lets put it to bed.

 

S!

 

 

Here I agree with you. For the rest, I'll leave to you the last word.

[Kurfurst]

Another thread kidnapped by the usual suspects and going down the toilet... :/

 

Did it actually occur to any of you guys that what would make the 109 behave realistically is not anecdotes and semi-complete information on accidents rates (btw an old post from Olivier suggest that there were about 1,5% of all 109s involved in some kind of landing/takeoff incidient, including a/c that were just damaged) but the geometry of the undercarriage, size friction of the tires and the relevant centre of Gravity point on the ground?

 

Accident rates cannot be parametered in the FMs, but things like CoG, friction vectors, torque etc. can be.

 

It seems to me that BoS has a fairly through modelling of the undercarriage, quite a bit more so than the old Il-2 series in which in all honesty all aircraft seemed to behaved as if they were "rolling" on ski. Just input the right parameters and the 109 or any other plane will behave close enough. After all the main culprit behind the swinging tendency was the tail heavieness of the plane on the ground, and it should come to no surprise that a setup like this increases the tendency to swing the *ss of the plane around a bit. Cars work the same.

[JtD]

The point could be made that nearly all aircraft destroyed in WW2 were destroyed in landing accidents, as very few of them completely disintegrated mid air. More seriously, as has been pointed out, damaged aircraft destroyed during a landing can be counted either way - so if 11.000 is right, there's still room for interpretation.

 

But, if you check fighter squadrons losses, you will find that a large portion of losses is not related to combat. This ratio goes up, the less capable/numerous the opposition was. First squad I picked (http://www.ww2.dk/oob/bestand/jagd/biijg52.html), shows ~250 combat losses again ~200 non combat losses. It's certainly not uncommon to have higher non combat than combat losses. Of course, not every non combat loss is a landing accident.

 

Technically, the wheel camber of the 109 was a bit problematic. Due to the camber, each rolling wheel generates an inward turning moment for the plane, which evens out as long as both wheels have the same load, but they don't have the same load for instance as soon as you start turning. So in any turn, the extra load on the outside wheel created a moment supporting that turn and if it was not countered, you could end up in a ground loop. Engine torque also creates asymmetric wheel loads, in particular when powering up. Vertical wheel installations don't have that feature. The 109 certainly did not benefit from this, but I suppose the bigger problem were that you had a 1500hp engine on a 3000kg aircraft, piloted by rookies that when most of the 109's were made, had barely finished basic flight school.

[DD_bongodriver]

And JTD has basically just explained the precise reason why the 109 got this reputation, it's not an anecdote, just one of those things accepted in history for what it is, there was probably never a need to make specific documents about it just so some internet nerds could fight about it 50 years later.

[Furio]

As far as I know, the FW190 had a stiffer shock absorber on one side to cope with prop torque, so it can be said that gear geometry was not everything. As I understand it, the Bf109 was designed with a narrow track gear to allow wings to be dismantled leaving the fuselage on the gear. Surely this made repair easier, and the life of inexperienced pilots harder. 

[Kurfurst]

And JTD has basically just explained the precise reason why the 109 got this reputation, it's not an anecdote, just one of those things accepted in history for what it is, there was probably never a need to make specific documents about it just so some internet nerds could fight about it 50 years later.

 

The reason the 109 got this reputation is that it had a temperamental nature on take off. All taildragger fighters of the era had the tendency to swing on take off, and it would turn into a groundloop if not checked in time. All warplanes of the era had a high accident related losses, it was between 20-40% of all losses, let it be RAF fighters, USAAF fighters, VVS fighters or LW fighters. The 109 was not much different from that, but it went medieval on you and groundlooped very quickly if you did not react quickly enough on take off. As one 109 pilot I have read put it, you had too treat the plane at every take off as it was the first. Those pilots who followed this never groundlooped, those who went easy and got overconfident after a while groundlooped and broke the plane.

 

Again this tendency can be easily modelled with correct parametering of the undercarriage and centre of gravity.

 

You are also wrong that it was not reasearched and documented during the war. The tall tail wheel of late 109 and limiting the castor angle of the tailwheel was a fix for this ground looping tendency, for example.

[Crump]

The Bf-109 did not have landing issues due to camber so please show post some engineering facts instead of just trying to increase your internet reputation at the expense of putting out false information.

 

FAA Advisory Circular - Landing Gear systems says paragraph covering alignment says:

 

 

As previously mentioned, a torque arm or torque links

assembly keeps the lower strut cylinder from rotating out of

alignment with the longitudinal axis of the aircraft

 

Just like I said before all the internet point scoring crowd joined in, the gear are shimmed to roll straight as part of the alignment process.  It is a pain in the rear to do so and while you plumb and calculate a ballpark, it is trial and error adding shims, reassembling the gear, and then rolling the aircraft to see if it stays straight.

 

If it gets out of adjustment, which it will, then it will not get fixed unless it is bad enough to report.

 

 

The manufacturer’s maintenance instructions give the

procedure for checking and adjusting tow-in or tow-out. A

general procedure for checking alignment on a light aircraft

follows. To ensure that the landing gear settle properly for a

tow-in/tow-out test, especially on spring steel strut aircraft,

two aluminum plates separated with grease are put under each

wheel. Gently rock the aircraft on the plates to cause the gear

to find the at rest position preferred for alignment checks.

 

 

Camber is the alignment of a main wheel in the vertical plain.

It can be checked with a bubble protractor held against the

wheel assembly. The wheel camber is said to be positive if

the top of the wheel tilts outward from vertical. Camber is

negative if the top of the wheel tilts inward. [Figure 13-30]

Adjustments can be made to correct small amounts of wheel

misalignment. On aircraft with spring steel gear, tapered shims

can be added or removed between the bolt-on wheel axle and

the axle mounting flange on the strut. Aircraft equipped with

air/oil struts typically use shims between the two arms of

the torque links as a means of aligning tow-in and tow-out.

[Figure 13-31] Follow all manufacturer’s instructions.

 

http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_airframe_handbook/media/ama_Ch13.pdf

[Crump]

 

I'm trying to be constructive

 

 

No you are not.  You are just trying to score points on a BBS.  We had our conversation on PM.

 

As for the distance to the CG and the mains, read the Weight and Balance sheets for the types.  You can easily see in the Spitfire and the Bf-109 by using MAC and seeing the location of the mains.  I am not going to argue with you over what amounts to stupidity about what the engineering data says.  Like all these arguments, it is in black and white.  If you don't know how to read it or do not know aviation convention, that is your problem.

Edited November 23, 2013 by Crump

[LG1.Farber]

.... As I understand it, the Bf109 was designed with a narrow track gear to allow wings to be dismantled leaving the fuselage on the gear. Surely this made repair easier, and the life of inexperienced pilots harder. 

It facilitated transport by rail which was a huge advantage, one train crew vs using 10, 20 or 30 pilots to shuttle them across Europe and into Russia with frequent refueling and the dangers of damage during bad weather not to mention take off and landing... 

[Crump]

 

The tall tail wheel of late 109 and limiting the castor angle of the tailwheel was a fix for this ground looping tendency, for example.

 

 

That makes a huge difference on tail draggers.  I changed my tailwheel from a flat sprung Scott to a rod sprung heavy duty homebuilders a few years ago.  Best move I ever made as far as landing goes. Main difference was the spring.  The flat spring was too soft and bounced considerably,  the rod absorbs the shock better without the bounce.

 

If your gear is running straight, your tires remain intact, and your tailwheel is properly serviced, any taildragger will land just fine provided the pilot does what he is supposed too.

 

What determines how fast a taildragger swaps ends is the distance from the mains to the CG.    What determines how easily it turns on its nose or how much we can get on the brakes is that same CG/Mains relationship.  What determines how much steering force we can exert is the distance from the CG to the tailwheel.  Hence the expression a "long coupled" tail dragger which has more steering force than a "short coupled" tail dragger.

[Rama]

Again, and again, and again, the personnal stuff...

It's too much work editing your posts, and you guys never understand anyway these threads are not the place for ego battle.

... locking...