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wheel pants and tire inflation

RV8R999

Well Known Member
Just installed my wheel pants. Wondering if anyone has modified them to allow tire inflation without removal? Was thinking of a 1" dia hole directly opposite the valve stem and using a plastic plug when flying.

Also - anyone have problems with only 5/8" clearance between tire and pant?

Regards,

Ken
 
Yes, a number of folks drill a hole opposite the valve stem for just this purpose. I drilled a 3/4 inch hole and bought an aluminum cap from the local Aircraft Certified Equipment supplier.

Also, you can get an valve extension, to pump up the tires. The valve extensions are common for tractor trailer tire valves.

Very handy...another optimization is to paint a strip on the inside edge of the tire when the valve is aligned with the hole in the wheel pant. This-a-way, when you need to put air in the tire, you can role the plane so the strip is in the correct position, w/out having to need two people to help align the valve w/ the hole, whilst moving the plane.
 
Ken,

and to answer the question about tire clearance, yes, you have to trim the wheel pants to ensure uniform clearance between the wheel pant and tires.

Otherwise, *when* the tire flexes on landing, it will grab the edge of the wheel pant and crack the wheel pant when the fiberglass give way.

I wonder how I know that? :rolleyes:
 
Ken,

and to answer the question about tire clearance, yes, you have to trim the wheel pants to ensure uniform clearance between the wheel pant and tires.

Otherwise, *when* the tire flexes on landing, it will grab the edge of the wheel pant and crack the wheel pant when the fiberglass give way.

Or worse - you'll cut the tire, it will go flat, and you'll end up sliding down the runway on the remains of your nicely-finished wheel pant. You can grind off about an inch in a single incident. And yup, you can bet I know that first hand.:mad:

I use the "Rule of Thumb" Ken - I like the slot width to be about as wide as the knuckle on my thumb, all the way around. I used much tighter clearances at first. After my cut tire, I enlarged it to thumb width, lost ZERO speed, and have had no further tire clearance issues.

Paul
 
yeah thats what I thought - 5/8" seemed a little close to me, 3/4 will be better. Thanks.

Good idea on the tire stripe!
 
Hole size

I found 3/4 kind of small - 1" allows more light to look for the valve stem. No need to paint a stripe on the tire.
Dan-N118KB
 
Straight Tire inflation tool.

Use the 1" hole if possible like a lot of others have. I market a straight tire inflation air chuck specially for the application of inflation of tires through the wheel pant hole. It has a straight chuck and air valve on a cnc machine 6061-T6 aluminum tube. Send me an email if interested. [email protected]
6
Link to Picture http://tinypic.com/r/ohs7rk/6
 
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Speaking of which....

...leads me to ask what RV-10 owners do here. I had 1" holes in my -6 but the wheel pants on the -10 are huge! I also had a white stripe on the outside of the tire which helped align the valve stem with the hole.

Best,
 
From someone else's idea............ I fiberglassed a short piece of PVC pipe (about 1/8" long) inside the wheel pant. This holds a light weight plastic plug from Home Depot, Lowes, etc to the pant very well. The plug is painted to match.

L.Adamson --- RV6A
 
The clearance thing

The clearance thing is not as clear as you might think. When you fly, when you land, when you have weight on the wheels in steady state condition, where the edge of the fairings are with respect the the tire, the angle of the fairing surface with respect to the tire surface and the position of the edge with respect to the tire rotation all need to be considered if you want to optimize the effectiveness of the fairing function which is to maximize speed. Van's has evolved the fairings at least once to improve performance and it pains me to hear about cutting access holes in the side and rationalizing that a 5/8" gap may be too small.

I provided some details in the thread about subfairings.

Bob Axsom
 
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Van's has evolved the fairings at least once to improve performance and it pains me to hear about cutting access holes in the side and rationalizing that a 5/8" gap may be too small.

I provided some details in the thread about subfairings.

Bob, I read through your thread on your subfairing ordeal. Why does it pain you to "hear about cutting access holes in the side" for tire inflation? Why does that cause you concern?
 
Drag

Bob, I read through your thread on your subfairing ordeal. Why does it pain you to "hear about cutting access holes in the side" for tire inflation? Why does that cause you concern?

Functionally it is fine but when you struggle for years to gain fractions of knots the idea of cutting holes in the smooth surface is the disturbing part - it's just a personal thing.

Bob Axsom
 
Bob- no way a 1" plugged hole will ever measure on any airspeed instrument you'll ever see in an airplane...the bugs on your leading edge will have bigger impact.

Ken
 
I'm sure you're right

I'm sure you're right but the pain remains. "Slippery slope" and all that.

Bob Axsom
 
Functionally it is fine but when you struggle for years to gain fractions of knots the idea of cutting holes in the smooth surface is the disturbing part - it's just a personal thing.

Bob Axsom

LOL! Got it, thanks. You know, Bob, maybe there's a 12-step program out there for you speed freaks. Google it ... :D
 
oh I'm with you..I'm a recovering speed-o-haulic myself. My cure was in realizing I could increase the speed of maintenance with simple mods that get me back to flying more quickly..this is the speed I focus on now!
 
valve stem access

Cleveland tools also markets a stainless hole cover and a stem extension(to screw on just for inflation and pressure checking then screw back off) I haven't tried it yet but looks like it will work.

Jay, RV-7A finishig, UT47
 
Just spoke to a buddy today who told of gluing silicone baffle seal to the edge of the wheel opening to seal it against the tire (rubs on tire a little). This mod alone was worth 3 knots on his F1 rocket. Apparently, the gap is critical. Now I have a new mod to try!
 
Speed is the only objective worth pursuing I believe

You know you spend most of your life working striving for excellence in aircraft and space projects with teams of the best and brightest as well as inspired fellow workers with some successes that give you pride and some failures that grind into your soul. All the time you know it will end and you spend 8 years building your own plane at home trying for excellence in that project as well. One day both the career and the building come to an end. That is not acceptable to me. I have to have a goal out there that I am striving for and it is not satisfied by going through all of the redundant processes of building another airplane like a production worker. I need to study things that I can modify to make my RV-6A go faster not necessarily to beat anybody but to push it to another performance plateau in speed. I love to travel with my wife but the personal thing that I reserve for myself is the challenge of thinking about ideas to make my plane go faster, conceptualizing a modification, implementing it, testing it, then keeping it or removing it and moving on to the next idea. It is unending and can provide satisfaction while just sitting on the toilet, vacuuming the carpet, laying in bed, etc. It gives creative meaning to life for someone who is retired and it is very satisfying even when the ideas fail. If you saw the movie "The Worlds Fastest Indian" you get the idea of what the pursuit of speed by myself on my personal airplane means to me. It is not a pursuit I want to give up.

Bob Axsom
 
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I'm right there with you Bob... tinkering and improving is the most enjoyable part of experimental aircraft. I'll be satisfied with just one more knot...
 
Striving for efficiency...

I need to study things that I can modify to make my RV-6A go faster not necessarily to beat anybody but to push it to another performance plateau in speed. ..... the challenge of thinking about ideas to make my plane go faster, conceptualizing a modification, implementing it, testing it, then keeping it or removing it and moving on to the next idea.

Bob Axsom

The EZ canards went through the same thing. Burt Rutan designed amazing airplanes with start of the art efficiency. BUT... thanks to people like Klaus Savier of Lightspeed Engineering and Shirl Dickey (E-Racer designer and sponser of RACE events for 20 yrs), a step change was acheived in EZ aircraft performance. Klaus designed ignition systems, props and wheel pants that made 15-20 kt speed increases. The RACE events brought out the best in builders to find places to reduce drag and maximize engine HP capacity via induction and exhaust system changes.

NONE of these improvements came from Rutan, rather, it was innovative builders, like Bob Axom. My hat is off to those all of those who push innovation of an already proven design. In the end, the rest of us wonder how the "identical" airplane that I have, goes 10-15 mph faster than I do.
 
wheel pants

The problem I have experienced with the wheel pants is one of damage due to rolling over the angle iron track of my hangar door. I have been forced to make ramps to solve this problem at my hangar, but on a recent trip to Airflow Performance they were damaged again. The angle catches between the tire and the wheelpat, preventing further forward movement.
I have elected to remove the damage with my Dremmel, and will reinstall and fly with the additional clearance. We'll see what effect it has.

On the subject of inflation, I have a spring-loaded button installed and use a straight inflator with built in gage.

BTW what tire pressures are you guys using on your 8's?
 
Take a look at Dan H's comments with regards to building inlets using glass impregnated rubber..it wouldn't be too difficult to build some foam molds to fill the gaps between wheel and pant and then apply the rubber Dan used. Then you could have a pliable and complete sealing of the gap around the tire.
 
How are you removing the valve stem cover through the Access hole?

I intend to cut an access hole also, but after looking at it today I am wondering how to unscrew the cover? Are you guys leaving them off?
Nordo
 
nordo

there is a socket size that fits snugly over the cap and is just tight enough to loosen and tighten. don't remember the exact size, but it works

fly on!!
 
Tire Radial and Lateral Clearance

The tire manufacturers have good data on minimum tire radial and lateral clearance to wheel pants, wheel wells, etc. You'll have to go through a few charts to calculate and there is a different clearance for radial and lateral clearance. Note the tire grows in service due to relaxation of the cords, and expands due to centrifugal force.

Go to:
http://www.goodyearaviation.com/resources/tiredatabook.html
Download Section 8 Engineering and Technical Data and have a look at Section 8.8

Note that these are MINIMUM clearances.
 
Other styles??

All I have ever seen is the hole with a cap type access for inflating the tires. Has anybody seen something other than this?

How about a hinged front section? Or how about the skirt style that were on cars in the ?60s or are now on some new fuel efficient hybrids?

Has anybody mounted the wheel pants with retractable doors I saw a few years ago at Oshkosh?

Like this
08_snf_0014.jpg
 
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