What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Balanced main wheel pant?

A5555

Well Known Member
Each 400 hrs I notice I have a slight play in the aft end of my wheel pants. I am able to tighten the axle bolts to remove the play but I suspect they will just become loose again over time. I believe it is from the main wheel impact load during landing. the wheel pant is not balanced. I may have added extra filler and paint to these to get them smooth and overload the trailing edge. it seems .75 lbs in the nose would balance them so that the during landing it is a straight down load and not a rocking load. hopefully, that would correct the loosening fastener issue. has anyone balanced their main wheel fairings? I am hesitant to do this because I don't like to add dead weight.... but I'm leaning that way. looking for any experience for this.

IMG_20211104_144719.jpg
 
Yes

I did this on my 6A, Steve, but from the beginning so I could never tell if it fixed anything. I used epoxy and lead shot mixture in the noses and went for balance around the axle axis, after paint.
 
I did this on my 6A, Steve, but from the beginning so I could never tell if it fixed anything. I used epoxy and lead shot mixture in the noses and went for balance around the axle axis, after paint.

that was what I was planning to do. do you still require periodic fastener tightening around the axel support bolts?

adding dead weight invalidates the concept of total performance in my mind.
 
Last edited:
I remember a report or two that adding nose weight to balance the pants cut down the likelihood of shimmy. It was a while ago and that's about all I remember of it.

Dave
 
I remember a report or two that adding nose weight to balance the pants cut down the likelihood of shimmy. It was a while ago and that's about all I remember of it.

Dave

I don't have shimmy just the fairing mounting bolts around the axle becoming loose over time.
 
I thought Vans had brought up the issue of the loose wheel pant brackets, the aluminum spacers needed to be replaced with something harder. Now I can’t find it, I was going to address it soon as well.
 
Steve,
If you need a little bit of lead, let me know - I have plenty. Another consideration for vibration in the wheel pant area has to do with turbulence created by air spillage from a complete lack of aerodynamics from a wheel pant that is ‘scooping’ some air due to inflight landing gear/wheel pant geometry. I have a friend who experimented with this phenomenon and came up with some very positive discoveries/outcomes. It sounded very logical to me, although a little positively optimistic, but you are an engineer and may have a different opinion. Come over sometime and I’ll tell you what I’m talking about. I may experiment with it myself when the time comes - next spring before paint.
 
I think the main source of the trouble is the landing impact loads and maybe to a lesser degree taxi on a rough surface. impact loads make fasteners do crazy things that you would not believe. I've witnessed underwater detonation testing for above water Navy equipment. my main wheel tire pressure of 50 psi doesn't help to soften the loads. adding weight to balance the fairing would help to direct the loads to the center and reduce the moment arm rotation effect but adding the weight itself could make the impact loads to the brackets even higher. I've decided to leave the fairing as it is and not add a balance weight. I wish I had made my wheel fairings lighter weight. Accept paint pin holes and go for light weight wheel fairings.
 
Last edited:
Steve,
If you need a little bit of lead, let me know - I have plenty. Another consideration for vibration in the wheel pant area has to do with turbulence created by air spillage from a complete lack of aerodynamics from a wheel pant that is ‘scooping’ some air due to inflight landing gear/wheel pant geometry. I have a friend who experimented with this phenomenon and came up with some very positive discoveries/outcomes. It sounded very logical to me, although a little positively optimistic, but you are an engineer and may have a different opinion. Come over sometime and I’ll tell you what I’m talking about. I may experiment with it myself when the time comes - next spring before paint.

mine are probably scooping a lot of air.
 
Last edited:
Steve

Throw the aluminium spacers away and replace with steel. Even a stack of washers will do a far better job of holding the fairings.
As I’m flying off grass I was forever tightening these until I changed.

Planearound makes a better spacer which I’ve fitted to my rv-10 build but I wish someone would sell one for the -7

https://planearound.com/shop/ols/products/two-wheel-fairing-bracket-spacers-for-rv-10-set-of-two


Regards

Peter

OK. I'll add this to the update plan. thx, Steve
 
Steve

Throw the aluminium spacers away and replace with steel. Even a stack of washers will do a far better job of holding the fairings.
As I’m flying off grass I was forever tightening these until I changed.

Planearound makes a better spacer which I’ve fitted to my rv-10 build but I wish someone would sell one for the -7

https://planearound.com/shop/ols/products/two-wheel-fairing-bracket-spacers-for-rv-10-set-of-two


Regards

Peter

I made a set for my 10, but never made one for the 6/7. If there is interest, I would be willing to make a batch and sell for $50 a pair. My wheel pants are off for a tire change right now, so not too hard to get the measurements.

Larry
 
Last edited:
Last edited:
I made a set for my 10, but never made one for the 6/7. If there is interest, I would be willing to make a batch and sell for $50 a pair. My wheel pants are off for a tire change right now, so not too hard to get the measurements.

Larry

Larry, the Mcmaster-Carr spacers are an exact match to Van's dwg. I can order several and send some along to you if you wish. Steve
 
correction

this location uses AN4 bolts so need to drill the ID of these spacers but still close.

perhaps mcmaster-carr 92415A053 is closer and then drill the ID for the AN4 bolt.

Capture(9).PNG
 
Larry, the Mcmaster-Carr spacers are an exact match to Van's dwg. I can order several and send some along to you if you wish. Steve

I never put the AL spacers in there, as it seemed like a bad idea. I made steel ones and have had no loosening in 800 hours.

Larry
 
I think the main source of the trouble is the landing impact loads and maybe to a lesser degree taxi on a rough surface. impact loads make fasteners do crazy things that you would not believe. I've witnessed underwater detonation testing for above water Navy equipment. my main wheel tire pressure of 50 psi doesn't help to soften the loads. adding weight to balance the fairing would help to direct the loads to the center and reduce the moment arm rotation effect but adding the weight itself could make the impact loads to the brackets even higher. I've decided to leave the fairing as it is and not add a balance weight. I wish I has made my wheel fairings lighter weight. Accept paint pin holes and go for light weight wheel fairings.

Does make you wonder how much aerodynamic efficiency you would give up to truncate the pressure recovery shape by shortening the back end of the pant. That would buy you some lighter weight and move the CG forward toward the axle.

How critical is the final 10-15% of the pressure recovery shape?
 
Does make you wonder how much aerodynamic efficiency you would give up to truncate the pressure recovery shape by shortening the back end of the pant. That would buy you some lighter weight and move the CG forward toward the axle.

How critical is the final 10-15% of the pressure recovery shape?

ah, the trailing edge is usually the critical portion.
 
Mcmaster-Carr steel spacers

these are the Mcmaster-Carr spacers. I'll but these in a floating vise on the drill press and open the ID to .254 inch.

DSCN5478.JPG
 
Last edited:
Wheel pants

I have posted before about a really bad shake in my left gear only on Wittman Tailwind. Balancing the wheel pant did nothing, waste of time. I installed a 2024 aluminum bar on the left side. 1 1/2" x 1/4", held in place with seven adel clamps with the rubber pads removed. Shake is now tolerable, much improved.
I have James wheel pants mounted similar to RV. The outboard screws would loosen every flight. 10/32 screws with countersunk washers into all metal locking anchor nut. On one occasion a screw departed in flight. I changed to AN3 bolts with large area washers, problem solved.
I used steel spacer bushings on the inboard wheel pant brackets along with all metal lock nuts. They were all loose at the 100 hour mark. This was on both sides even though the right side does not shake.
 
drilled steel spacer ID

seemed to work fine. 10 minute job. jaws float on the drill press surface so the drill self centers in the hole.

IMG_20211106_164405.jpg
 
Back
Top