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  #1  
Old 08-26-2015, 09:20 PM
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donaziza donaziza is offline
 
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Default 45 psi tire press & all due respect to Walt Aronow

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,, 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.
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  #2  
Old 08-26-2015, 09:31 PM
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Infidel Infidel is offline
 
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I'm not Walt but, I fly off of a grass strip that at this dry time of year is very rough. Earlier in the season when the ground was still moist, I used +-25lbs and it was a happy medium. Even when landing on asphalt. I've since changed to 35 lbs and while it feels better on pavement, my drought stricken grass runway begs for 25 lbs again.
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Old 08-26-2015, 09:43 PM
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I may bounce 3 or 4 times on an occasional landing, but I haven't yet correlated that to tire pressure or runway surface. I've landed on both pavement and grass with 40lb in the tires with no issues... in fact I find it easier to wheel it on with the higher pressure. YMMV?
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Old 08-26-2015, 09:57 PM
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I had the same experience. 45psi is way too much. It's like rolling on a Flintstone wheel which makes complete sense if you speak to a tire manufacturer about what should drive your selected pressure.
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Old 08-26-2015, 10:58 PM
crabandy crabandy is offline
 
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I run 48 psi in my mains and haven't noticed any issues, I've found I bounce it just as well at lower pressures.
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  #6  
Old 08-27-2015, 03:47 AM
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When I was having similar issues after moving my tire pressure up 45psi I found I was flying way too fast on short final, the flare, and even touch down. Once I slowed my approaches down and never letting the airplane touch down until it won't fly anymore my landings are now much better. I do have an AOA system installed with the audio piped into the headset which makes it very easy to safely slow down and feel comfortable. I now find myself watching other RVs on landing and noticing the landing speed vs quality of landing, which I firmly believe supports my initial statement above.

Just my 2¢
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Old 08-27-2015, 05:53 AM
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I set 50. Of course, all my landings are above average, like 90% of pilots.

Gents, this has nothing to do with landing ease or ride quality. Running higher pressures means less carcass heating, less tube chafing, less cord strain, less chance of wheel and wheel pant damage, shorter takeoff roll, less tread wear, and probably a few other points I have forgotten right now. I can understand if those with round gear legs must run some particular pressure to kill shimmy; it's an unfortunate crutch, the sort of compromise that sometimes must be made. On an RV-8 with flat gear? Pleeeease....
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  #8  
Old 08-27-2015, 06:37 AM
humptybump humptybump is offline
 
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I switched from 32-35psi to 45/48psi when I replaced my tires (tyres) and went to 380's.

When I bounce or find the plane side stepping a bit it's all my fault, not the tires. And when I do bounce, I'm much less worried about the wheel pants.

I do think the higher pressure helps a bit with my take off distance.
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Old 08-27-2015, 06:49 AM
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Toobuilder Toobuilder is offline
 
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I run 45 in all my airplanes. When it gets hard to push out of the hangar I know it's time to add air. There is a big difference in rolling resistance between 30 and 45.
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Old 08-27-2015, 06:59 AM
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Sam Buchanan Sam Buchanan is online now
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Quote:
Originally Posted by DanH View Post
<snip>
I can understand if those with round gear legs must run some particular pressure to kill shimmy; it's an unfortunate crutch, the sort of compromise that sometimes must be made. On an RV-8 with flat gear? Pleeeease....
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.
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Last edited by Sam Buchanan : 08-27-2015 at 07:05 AM.
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