VAF Forums - 45 psi tire press & all due respect to Walt Aronow

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- - 45 psi tire press & all due respect to Walt Aronow (https://vansairforce.net/community/showthread.php?t=129021)

To all,
After reading the discussion about what tire to use I referred to the document provided by Cleveland when building my RV8.
The kit provided was #199-102 specifically states 31 psi., the attached note #5 states "over inflation" may result in explosive tire failure.
Hope this helps those with questions.

Mark W.

Quote:

Originally Posted by donaziza (Post 1009263)

Walt, With all due respect, maybe a month ago, you had advised guys to put 45 psi in their tires. That sounded good to me, so I did it. Then I went down to land on a grass strip. After maybe 4 or 5 landings, all on the same approach,:D, I realized I had to go around. When I got back home to my cement runway, I found I was "dancing" all over the runway before I could finally confirm my wheels were solidly planted on the cement. The next time I went flying, and then tried landing at home port, I seemed to be moving sideways even though I knew my wheels where on the cement. I don't normally have problems landing. I think I need to let 5, maybe 10 psi out of my tires. Anyone else notice this? Walt? I'm all ears.:D

And with all due respect, I doubt the higher tire pressures are the cause of your landing problems, I agree that soft tires will increase drag, reduce bouncing or skipping and "soften" your landings, but the root cause of those problems are likely your landing technique.

Another reason I like 45-50 is the minimum (IMO) should be 35 so if you are like most folks and don't check your pressures as often as you should then you are less likely to fall below the min.

I can honestly say that 100% of the flats I have fixed have almost certainly been caused by low tire pressure.

I also agree that if you suffer from shimmy that a lower pressure may help, but I think that should be a last resort, tires issues, out of round tires, balancing etc will all tend to excite shimmy.

When I was first flying my Phase 1, (RV7A) I spent a lot of time chasing both nose wheel and main wheel shimmy. I had started with 35lbs, went down, went up and documented everything including air temps. It was too variable. I then installed wooden stiffeners and it reduced the occurances of shimmy but did not eliminate it. I then bit the bullet at 100hrs and changed from the factory tires which still had almost new tread wear to FlightCuston 3 tires. Instantly fixed the shimmy problem that it turns out I had on nearly all landings but I attributed to "normal". I only "noticed" the really bad shimmy:eek:

I wound up going with the anti-splat nose gear and wheel mods and that fixed the nose wheel shimmy. Now I run 45psi all the way round, run the nose wheel pull out force to 28lbs instead of 22lbs and everything is great.

All in the name of education and recreation:D

I've been flying my '8 for 15 years. I've always run my tires at 45lbs. It doesn't dance around on the runway.

Quote:

Originally Posted by Sam Buchanan (Post 1009333)

Distinction does indeed need to be made between RV-6 and RV-4 gear and the other RV models, especially the RV-8. This is not a case of one size fits all.

There is something in either the design or construction of tail draggers with round gear that can excite shimmy at certain speeds. "Solutions" have been discussed for many years (remember the wood stiffeners that were in vogue twenty years ago?) but for many of us running tire pressure less than 35 psi is the only way we have found to dampen shimmy, especially after tires have worn to some degree. This may not be optimum pressure for the tire but is a case where compromise must be made in order to have a plane that doesn't feel like it is trying to shed its gear at certain speeds.

And yes, trying to land a tail dragger too fast often doesn't end well. :)

Not sure about tail draggers but like many, I changed from 35 to 50 or even 55 pci and don't have any more issues landing that I did not have before. On the nose wheel however, I have learned that this is one way to keep it from getting a pin hole and therefore a flat.

RV8 Tire Pressure

During my Phase 1 testing I asked Vans what he used in their RV8 prototype and I was told 50. That is what I am using. I can blame my bad landings on many things: gusts, uneven terrain, CG loading, number of spectators, fatigue, hangover, etc, etc.

I suffered several flats in my first few years of flying as did one of my local buds. We now run retreads, good tubes and more air. 40-45lbs.

Works like a champ....no flats in almost 2 years. Seems like all is golden now.

Knock on wood... More pressure does certainly help.

Leak guard tubes..the greatest invention since sliced bread...and nilla wafers.

I run 50 all the way around on all of them.

Vic