Wheel pants alignment slightly off

[briantucker]

With everything lined up to the wheels and brackets with proper spacing on top of the wheel it appears my wheel pants are off by about .75” fore/aft and about 5/8” up/down. I cannot figure out where this difference is coming from but adjusting them to be even would be a pretty significant change in tire clearance and bracket location. Each pant is perfectly level and aligned with the longitudinal axis. From what I can tell my right gear leg is shorter than the left one by about 5/8” (measured from the centerline of the plane, the right wheel is about 1/2” closer to the center than the left one), so perhaps that’s where the difference is from.

Has anyone else experienced this and do you think it will cause any noticeable difference in flight characteristics?

 

[Desert Rat]

I doubt that it will cause any noticeable issues in flight. Pretty simple to fly both with and without them and verify one way or the other.

Having said that, My OCD wouldn't allow me to leave them like that. How big is the gap around the tire? Hard to tell for sure from the picture, but it looks like you have room to adjust, drill new mounting holes, and then upsize the tire gap to make it symmetrical on both sides without it getting too huge. Also, don't forget that when you get weight on wheels, the sidewalls will bulge out so that gap is smaller on the ground than what you're seeing with the tires up in the air.

If you raise the lower one, the clearance to the tire will automatically get smaller anyway, so trimming to fit the new position and make it match the other side might not be too difficult.

 

[bjdecker]

...There was that one hard landing that one time.....

Brian -- in all seriousness, take everything apart, and see where the axles "sit" relative to the ground, centerline, etc. My guess is there is indeed a slight difference between them that's causing this.

As far as aerodynamic issues -- doubt it; but OCD - she's a tough mistress; very demanding....

 

[Ralph Inkster]

Variances in gear leg bracket production welding and gear leg production bend.
Should not affect flight characteristics. But this is the reason Vans instructs you to measure your wheel centers back from datum line during W&B calculations, (do not use example measurements in the manual). Every RVs gear leg geometry will be slightly different.

 

[lr172]

i was informed by vans that the up down alignment has a very minimal impact. however, the parallelism with centerline has a significant impact due to the yaw introduced if they are not parallel.

 

[mc607]

My 2 cents worth. Double check that the plane is level, most floors are not. You could double check that the pants are out, relative to the plane, not level. Put a long straight edge across the canopy side rails and measure down to the top of the wheel pants.
If your pants are aligned for proper toe in then I would leave them and build on. Any adjustments/reworks to the pants, that appear finished, would not be worth the effort and you would likely end up with slightly different wheel projections out the bottom of the pants. This could cause a slight yaw affect, which you likely don’t have now.
Turn the laser off and walk around the plane and see what it looks like. Ask someone else if they notice it. I highly doubt those small variations are visible with the laser back in the case. As mentioned by others, it’s not an aerodynamic issue.
Side note: can you imagine going around KOSH with a laser and checking all those RV’s that have been flying straight and level for years.

 

[elev666]

Also, you may want to consider that your engine does not sit straight if you’re using the front of the spinner for a datum to drop a plum bob from to get a center Line, I’m currently chasing a slight yaw issue with just my gear leg fairings / upper intersection fairings on and off, very tedious, and time consuming

 

[briantucker]

Double check that the plane is level, most floors are not

Plane is level in pitch and roll on the longerons. The floor has about a .5" slope per 5 feet and I made sure to not measure anything off the floor so it's somewhat ironic that my gear legs are off by the same amount.

Center line was determined using both a laser from the tip of the spinner to the tail and then double checked with plumb bobs on the measured centerline between the two riveted longitudinal spars on the fuselage belly. All are inline.

If your pants are aligned for proper toe in

Toe in is correct, though they have about a 2 degree difference in camber.

As far as aerodynamic issues -- doubt it; but OCD - she's a tough mistress; very demanding....

My inclination is to leave them as is if there isn't likely to be any adverse affect in flight. I'd assume that any adjustments that expose more/less of the tire would introduce a similar effect as the difference in height, maybe more. But OCD... currently taking a break from that relationship. She hasn't called yet but I know she will. Should probably block that number for my own sanity.

 

[riobison]

Plane is level in pitch and roll on the longerons. The floor has about a .5" slope per 5 feet and I made sure to not measure anything off the floor so it's somewhat ironic that my gear legs are off by the same amount.

Center line was determined using both a laser from the tip of the spinner to the tail and then double checked with plumb bobs on the measured centerline between the two riveted longitudinal spars on the fuselage belly. All are inline.


Toe in is correct, though they have about a 2 degree difference in camber.


My inclination is to leave them as is if there isn't likely to be any adverse affect in flight. I'd assume that any adjustments that expose more/less of the tire would introduce a similar effect as the difference in height, maybe more. But OCD... currently taking a break from that relationship. She hasn't called yet but I know she will. Should probably block that number for my own sanity.

They need to be parallel or you will experience yaw one way or the other. I measured center from the motor mount and dropped a plumb bob from there. The engine is off set a bit so going off the spinner may not be as accurate.