Flaperon Hinge Pin free play

[Lukeh]

I noticed free play on both outer hinges on Savannah S. 

Will I need to change bushing and pin, or could there be a more serious problem concerning metal parts of the wing and flaperons?

Anybody has done this?

[skippydiesel]

Hi Likeh,

Sorry not familiar with Savannahs, however I am anxious about the potential wear in the hinge pin design of my Sonex flight surfaces.

Still good, but only have a bit over 250hrs Hobbs.

The Sonex maintenance advice is to use a PTFE rich dry spray lubricant, on the hing mechanism. Dose Savannah recomend similar? If no, this may be a future wear mitigation strategy you could adopt.

There is a wide range of such lub's on the market .

😈

 

Edited Tuesday at 11:45 PM by skippydiesel

[Lukeh]

11 hours ago, skippydiesel said:

Hi Likeh,

Sorry not familiar with Savannahs, however I am anxious about the potential wear in the hinge pin design of my Sonex flight surfaces.

Still good, but only have a bit over 250hrs Hobbs.

The Sonex maintenance advice is to use a PTFE rich dry spray lubricant, on the hing mechanism. Dose Savannah recomend similar? If no, this may be a future wear mitigation strategy you could adopt.

There is a wide range of such lub's on the market .

😈

 

Thanks, I understand using the PTFE spry is recommended now. ICP suggest "White grease, Renolit ZT2". Unfortunately I did not notice in time  and have problem on two outer flaperon hinges now. I will greese remaining hinges ASAP.

[Lukeh]

I noticed a discussion on alternative bushing, made from bearing-grade polyester (PETP-GLD130 ‘TX’  , Sustadur PET GLD 130) or such.

I was hoping some of the participants would share their experience and approach they used, as the thread contains more different paths and suggestions and not much feedback from the real use? 

 

@JG3 ,@IBob , @Kyle Communications , @facthunter , @FIL65 , @eightyknots , @dan tonner ? (sorry for spamming you) 

 

Edited Wednesday at 12:03 PM by Lukeh

[Kyle Communications]

I have used the brass bushings. The biggest issue is making sure the bushings are installed correctly. The main thing is to make sure the bushing is actually working as a bush. Most from what I have seen especially with wear is the bushing is rotating in the alu hangar bracket. You can over tighten the setup. My latest build I have loctited the bushes into the right sections to make sure they cant rotate in the housing. You want the bolt only to have the bush rotating around it.

Making them from teflon or similar still has a issue if the bush is rotating. 

 

[Lukeh]

13 hours ago, Kyle Communications said:

I have used the brass bushings. The biggest issue is making sure the bushings are installed correctly. The main thing is to make sure the bushing is actually working as a bush. Most from what I have seen especially with wear is the bushing is rotating in the alu hangar bracket. You can over tighten the setup. My latest build I have loctited the bushes into the right sections to make sure they cant rotate in the housing. You want the bolt only to have the bush rotating around it.

Making them from teflon or similar still has a issue if the bush is rotating. 

 

Thanks Kyle. I am afraid you made me confused even some more. I was convinced after long thinking, that the original bushing is by the bolt fixed to one of the hangars let's say to the wing one, wing-bushing-bolt are connected and do not move, while the other hangar (flaperon) rotates around the outside of bushing aluminium on metal.

I could not get my head around this but that is how I undestood it. Not that the bolt rotates inside of the the bushing or bushing around the bolt. But you seem to suggest the later.

Edited 22 hours ago by Lukeh

[Kyle Communications]

yes the bush is fixed and it rotates around the bolt. What most have done from what I have seen is they tighten the bolt too much so what happens is it locks into the bush and the bush rotates in the aluminium...thats not good. It wears out the bush and the hangar bracket. It con only be the bush that rotates around the bolt...just like a door hinge

Think of it this way. The bush is locked into the hanger bracket and must be fixed. the bolt head is always on the L shaped alu that is connected to the ailerons and it doesnt rotate so it must turn inside the bush when the aileron moves. If you look at the manual the bush head is always on the other side of the hangar bracket and the castellated nut is on the bigger flange of the bush. That nut needs to rotate on the head flange of that bush.

When I go to the hangar next I will see if I can do a video to explain it and show it

 

Mark

 

[Lukeh]

9 hours ago, Kyle Communications said:

yes the bush is fixed and it rotates around the bolt. What most have done from what I have seen is they tighten the bolt too much so what happens is it locks into the bush and the bush rotates in the aluminium...thats not good. It wears out the bush and the hangar bracket. It con only be the bush that rotates around the bolt...just like a door hinge

Think of it this way. The bush is locked into the hanger bracket and must be fixed. the bolt head is always on the L shaped alu that is connected to the ailerons and it doesnt rotate so it must turn inside the bush when the aileron moves. If you look at the manual the bush head is always on the other side of the hangar bracket and the castellated nut is on the bigger flange of the bush. That nut needs to rotate on the head flange of that bush.

When I go to the hangar next I will see if I can do a video to explain it and show it

 

Mark

 

Kyle I don't see it. This is from maintenance manual - the original bushing installation. The head of the screw seems to touch the bushing directly, pressing it to the left bracket. How can the screw rotate inside of the bushing? Besides, the bushing's OD is 6mm, it goes through both brackets, AN4 washer has ID 0.265 inches (6,7mm)...

This gets weirder and weirder. I probably will not understand until I dismount it and see.

I looked it up in the Italian printed construction manual now and it does not make it easier. For example they say the bushing is mounted from the inside and screw from the outside of the aircraft (always), but the brackets have different order on inside hinges to the order of outside hinges.

Edited 12 hours ago by Lukeh

[Kyle Communications]

Thats interesting...that arrangement is different in my manual the drawing show the bolt head on the head of the bush. Yet I only have the photo in my manual the english one and from around 2011 and it appears to show the nut on the bush head.

 

Either was it doesnt matter. What ever part thee head of the bush is on that is the part the bush needs to NOT move in so really needs to be loctited if its not a press fit

 

 

[Kyle Communications]

The bolt will always need to have the bush rotate around it. Or the bush rotating around the bolt. You cant have the bush rotating through both alu parts otherwise what would be the point of having a bush you could just have a bolt through the hole

The manual for the Savannah has always been terrible

 

[Lukeh]

30 minutes ago, Kyle Communications said:

Thats interesting...that arrangement is different in my manual the drawing show the bolt head on the head of the bush. Yet I only have the photo in my manual the english one and from around 2011 and it appears to show the nut on the bush head.

 

Either was it doesnt matter. What ever part thee head of the bush is on that is the part the bush needs to NOT move in so really needs to be loctited if its not a press fit

 

 

to add to the confusion there is even different manual, showing different ICP setup. Probably older version, that JG3 have had. 

https://www.aircraftpilots.com/forums/topic/35271-improved-aileron-bushes/page/2/?&_rid=12414#findComment-447599

 

Edited 12 hours ago by Lukeh

[Kyle Communications]

Yes in that thread the drawing Ibob did is how I have always done mine . On my original build and this rebuild as well.

John Gilpin got larger teflon bushes made but you had to ream out the hanger brackets and also the flaperon L angle mounts

 

[sfGnome]

This may possibly add more confusion (sorry if it does), but here's the hinge bolt setup on the Ventura from the latest manual chapter dated April 26. I have no idea whether it is the same as the Savannah, but the two planes are very similar in many respects. "Inner" and "Outer" in this context are referring to each flaperon, so there's 2 pointing one way and 2 the other way on each wing. On this setup, presumably the bushing is fixed in the flaperon hinge, and the bolt is fixed in the wing hinge so, as Kyle said, the bolt would be rotating inside the bush.

 

On a related point, I asked ICP about an Australian equivalent to the specified white grease, and they said "It is just a white grease, anti-corrosion, water resistant, very dense, protective.
No other relevant properties, anything used on boats it will be perfect."

[Kyle Communications]

The white grease is Lithium grease. I used to use a silicone grease years ago but now I have swapped to the Lithium.

Yes it seems now that is exactly opposite to the original way. So who knows which way is correct.

So long as the bush doesnt tun inside the alu would make the most sense. The whole idea for a bush is to have the bolt rotate inside the bush and not the bush rotate on a surface that is loaded.

The ideal would be to have a fixed bush pressed into the wing hanger bracket and another bush fixed into the flaperon bracket. A washer separator like they have where the 2 smaller parts of the bush meet. This would make more sense to me

I hope the Ventura manual is better than any of the Savannah manuals

'

 

Mark

 

[Lukeh]

9 hours ago, sfGnome said:

This may possibly add more confusion (sorry if it does), but here's the hinge bolt setup on the Ventura from the latest manual chapter dated April 26. I have no idea whether it is the same as the Savannah, but the two planes are very similar in many respects. "Inner" and "Outer" in this context are referring to each flaperon, so there's 2 pointing one way and 2 the other way on each wing. On this setup, presumably the bushing is fixed in the flaperon hinge, and the bolt is fixed in the wing hinge so, as Kyle said, the bolt would be rotating inside the bush.

 

On a related point, I asked ICP about an Australian equivalent to the specified white grease, and they said "It is just a white grease, anti-corrosion, water resistant, very dense, protective.
No other relevant properties, anything used on boats it will be perfect."

@Kyle Communications Still, in the sfGnome pictures - the extended rim of the  busher SC210 lay directly on the castle nut and screw head lay directly on the wing hinge. It would seem to me, that neither should move against each other, busher against the wing hinge, nor the screw against the busher. And flaperon hinge does move/rotate against the buhsher outside. Aluminium hole in flaperon hinge rotates on brass busher.  Explain, how this understanding is wrong?

[facthunter]

It's not a well engineered arrangement at all. Nev