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Some wheel pants questions

00Dan

Well Known Member
I’ve been working on PR wheel pants for my -4 and have a couple questions.

Is there a tolerance for the alignment? Even with following the instructions for building up the bracket attach area both pants fought me when aligning. I got one to be straight but the other is toed in about 1/8”. My plan at this point was to fly it and see if it causes a noticeable yaw. From others with experience, what should I expect?

I understand the tire gap recommended can range from 1/2” to 3/4” for most people. With 5.00x5 tires and weight on wheels my current gap is not quite consistent but it’s about 1/2” at minimum. Should I open this up any further or is it probably okay? Along the split I’m running up against the lower nutplate so I can only trim so much more without redoing that. On a side note, is there a good way to trim these neatly? Using the dremel it’s a bit tricky to get curved cuts, such as along the back and front of the tire.
 
My experience says that yo0u should be able to fit an average sized male thumb in between the pant and the tire all the way around. Less than that and you risk tearing up your pants if a compressed wheel clips the opening. I trim those with a sanding disk on a die grinder - makes a very nice carving tool.

Paul
 
Invest in a 1" carbide straight burr that will fit in your die grinder motor. Goes through FG like paper and offers just enough resistance to make a nice smooth trim cut.
 
re: alignment, I know that the leg fairings are very sensitive to alignment and even a small error will create yaw. The horizontal alignment of the pants will also create some yaw, but I believe not as sensitive as the leg fairings. I just don't have enough data to say how much or little influence they have on yaw.

Larry
 
How much clearance.

Take your best advice, then once things are mostly done let the air out of the tires and see what you've got. Better to know ahead of time what is going to rub and what is going to drag on the ground.
 
Clearance

Easy way to work on the 8’s wheel pants ….. bolt the leg to the floor
 

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Clearance

Another pic
 

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A follow up question after doing some testing: would a misalignment or excessive tire gap be responsible for a significant speed loss? My cruise speed has dropped 5-6 knots with the pressure recovery fairings compared to my old one piece fairings. I’m inclined to look at my power plant first given the magnitude but wanted to see if any similar experience has been had, all else equal. For what it’s worth, I don’t notice any significant yawing moment but I have electric rudder trim that may be masking it.
 
Ah fiberglass wheel pants, bane of my existence.

I am still fighting to get a good alignment on these and the yaw chasing is almost to the point that I am ready to completely disassemble the pants, remove the bracket and fill in all the holes so I can start over. One of the biggest issues I’m encountering is that when I aligned the outboard attach bracket per the plans, it serves to pull the entire pant way out alignment. Pushing the tail back into alignment to drill the inboard holes results in a significant load on the outboard bracket and in many cases a deflection of the inboard attach bracket, making hole locating quite the exercise. Per the plans, I added several layers of fiberglass to the point inside where the outboard bracket attaches to attempt to level this area and mitigate the geometry issues but it appears to have not been enough. Am I missing the plot here or is the solution truly just to lay up a fat spacer to get that area flat on the inside?
 
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