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New wheel pants

houndsfour

Active Member
I've been flying the "old style" wheel pants for 8 years. They look good and do the job. Well I thought they did. I was told by a "friend" the new style wheel pants would add 8 knots and thats good for gas mileage.
Question, has anyone installed the new pants replaceing the old style?
Is it worth the trouble and do you really gain 8 knots?
Thanks
Rich
N721ET
 
When we replaced the old pants, gear leg fairings, and intersection fairings on Louise's RV-6 with the latest stuff, we gained about 6 knots - and for us, that was certainly worth it. Installation took a week of evenings, and then of course, there was final finishing and paint.

Paul
 
What is "new" and "old"

As a relative newbie...I am not sure what folks refer to as new and old. I am not the builder but the flyer of an '05 RV7...if that helps.
 
"Old" wheel pants are fairly narrow, and flat sided, and hug the wheel sides closely.
"New" wheel pants are also called pressure recovery pants, and are "fat", rounded, and larger overall than the old ones.

Check out a few RV photos, and you will be able to see the difference.
 
A fixed pitch propellor will give slightly more speed increase than with constant speed due to the engine rpm increase. The increased rpm will provide proportionally more power from the engine.
 
A fixed pitch propellor will give slightly more speed increase than with constant speed due to the engine rpm increase. The increased rpm will provide proportionally more power from the engine.

Only if it's optimized for high speed cruise. And then it will be a slug for climb. Take your pick..........as you can't have it both ways.
Since climb is so important around here, in mountain country, my 6 with the C/S will beat the fixed pitch.
 
A fixed pitch propellor will give slightly more speed increase than with constant speed due to the engine rpm increase. The increased rpm will provide proportionally more power from the engine.

You could however run the constant speed prop at the same rpm as the fixed pitch and net the same HP. If your not full throttle operation you could net the same HP at a slower rpm.

George
 
Kurt,
What problems, if any did you have installing the "fat" wheel pants?
Did you have to change the mounting plate or the landing gear fairings?
Sounds like 9 MPH is worth the change.
Thanks
Rich
N721ET
 
Pants

Rich,
Yes, you will need new brackets and pant to gear leg fairing. I used my old leg fairings and glassed the the fairing to the pants instead of screwing them on. I would do it again the same way.

Hope this helps.
 
Even if you get 1/3 Kurt's gain it's worth the effort and cost

First let me say that a 9 kt increase in speed is more like what I would expect from no fairings to wheel fairings and it is more that twice the improvement that I achieved with my best speed mod. However, this is an example of actual experience that validates improvement from the change.

When we built our RV-6A over an 8 year period, Van's was in transition to new cowl, new vertical stabilizer/rudder and new landing gear fairings. We got the new cowl, old vertical stabilizer/rudder, new fiberglass main strut fairings from Tracy Saylor, new fiberglass nose strut fairing from Van's (I think this was a special order), new main wheel fairings and old nose wheel fairing.

In trying to improve the speed I developed subfairings to go on all three wheel fairings extending the bottom down to 3/4" above the ground. The addition to the new pressure recovery main wheel fairings made a fraction of a knot increase in speed but the addition to the old flat sided nose wheel fairing resulted in a dramatic 3kt gain in aircraft speed. I think this experience also validates the relative inefficiency of the older flat sided design, though in a different way.

Bob Axsom
 
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question again

I do alot of grass field flying. What, if any, problems would grass strips cause the larger wheel pants?
Rich
RV-6 N721ET
 
Not a problem in my experience

Before I added the subfairings I landed at grass strips with no problems. I have not visited grass strips since I added the subfairings.

Bob Axsom
 
Wheel Pant replacements

Do y'all have pics and/or build website on the wheel pant replacement operation ? Thanks, Jeff Barnes
 
Wheel faring comparisons

I see in this and other threads that the fat "pressure recovery" wheel pants have advantage over the older van's narrow wheel pants. Sam James has a narrower set of wheel pants that he sells. Has anyone done a comparison of the Sam James pants with the pressure recovery wheel pants of vans?
 
Interesting to see this old thread pop up just now. I just completed the install of Van's pressure recovery wheel pants on my 1993 vintage RV-6 yesterday. I've flow it to verify trim before painting, but didn't do any real air speed testing. The old pitot tube has been swapped for the Van's part as well so any numbers I have will be suspect unless I put the old pitot back on for testing. I also changed the old style tail wheel assembly out for the new spring and full swivel tail wheel.

It's got a FP Warnke prop and 150hp O-320 so it will be intersting to see if it seems like it's gained anything. I'll be heading to OSH from central California next weekend so I'll be able to get some decent cruise numbers.
 
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Doug,
What were your cruise numbers and power settings before the change?
Jay

Jay, got home late but I got your message, I'll call you tomorrow.

I usually run part throttle until I get high enough to run 2550 or less with full throttle, just a preference. 8,500/9,500 normally works for that, and I can keep the fuel flow at 8 gph or less. I don't have my notes here, but I was getting 155 - 160 KTAS at those settings. I'm calculating that with an E6B, KIAS, OAT and PA.

On a quick test hop prior to painting the new pants I was at 9400 PA, 16C, and I think it was 137 KIAS. That came out to about 163 KTAS if I remember correctly. I need to look at my notes as I was most concerned with trim.

I really need to do a GPS box down low and see if my indicated speeds are good.
 
Hey there,

I'm working on an RV-6A and would appreciate seeing some specific 'before and after' GPS cruise data on the 'old pants and fairings' vs the 'pressure recovery pants and new gear fairings'.
 
I see in this and other threads that the fat "pressure recovery" wheel pants have advantage over the older van's narrow wheel pants. Sam James has a narrower set of wheel pants that he sells. Has anyone done a comparison of the Sam James pants with the pressure recovery wheel pants of vans?

I'm ready to buy and would also love to hear any data or opinions on: Sam James vs. Van's Pressure Recovery.
 
I'm ready to buy and would also love to hear any data or opinions on: Sam James vs. Van's Pressure Recovery.

+1 - I have both (Sam James & Van's Pressure Recovery)sitting here and will install one or the other, hopefully not both. Installation of just the fast one will help.
 
I have the SJ retrofits

(by the way, I like Brad's suggestion!) ----- The previous owner, who did the mod, said the mod made a significant difference in the -6A --- the plane was built early 90s with original Van's wheel fairing design. My only complaint is the number of fasteners to install/remove the SJ fairings ---- real pain.
 
If it ain't broke...

Question, has anyone installed the new pants replacing the old style?
Is it worth the trouble and do you really gain 8 knots?
Thanks
Rich
N721ET

Rich,
1. Yes. I have done both. I swapped original pants/aluminum fairings for PR/new fairings on a friends RV4. I also swapped Sam James pants/fairings to Van's PR pants/Team Rocket fairings plus 380X150X5 tires on my Harmon Rocket. Not too difficult but as mentioned requires new brackets and glass/paint work.

2. Depends. After testing on my friends 4 we gained an honest 5 knots. My Rocket didn't lose any speed from the Sam James>Vans swap. However, I gained a larger tire and footprint for my gooey/short turf strip I operate from. I installed the Vans PR pants/fairings with 380 Tires on my RV6X as well.
http://www.vansairforce.com/community/showthread.php?t=23360&highlight=bushwheels+Rocket

I personally wouldn't change from the old style to new style if they look good and aren't cracked or falling off. $400 buys a nice weekend trip of 100LL. :)

V/R
Smokey
 
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