Tire pressure?

gusc · Post by **gusc** » Tue Oct 14, 2008 22:32

I've been using the 1psi/100lb gross weight for 50 years and haven't cut off a valve stem yet. I used this thumb rule with two Champs, a Stinson and a Navion.

I just yesterday inflated my Champ's 600s to 14.5 psi knowing that they will leak down before I get it annualed and flying again plus the weather will be getting cooler soon.

I almost bought a very nice BC12D T-Craft for a really good price, but among other things I never could land it without awful bounces. I couldn't figure this out because I had quite a few hours in T-Crafts and never had a bit of trouble before. I thought I must be getting pretty rusty!!

It was many months later that I finally figured out the tires probably had 24-30 psi because the guy selling it had much heavier aircraft in his hangar and probably didn't know better. I could have gotten it for $10,000 less than I paid for the Champ and it was in perfect condition.

Paul Agaliotis · Post by **Paul Agaliotis** » Wed Oct 15, 2008 18:25

Somewhere along the line people attributed the wheel cracking to tire pressures. My feeling is they are not related. The wheels are just too light for the application. The tire pressures listed in the Service Manual were for the old 2 ply tires. As the ply ratings increased so did the inflation presures.
Paul

Dennis · Post by **Dennis** » Thu Oct 16, 2008 11:27

Paul,

As I sure you know the Model DHB Champ wheel is rated for 1000# static load yet the tripacer wheel is stamped with the same Model DHB yet it has a static load of 1500#. Both wheels appear to be physically identical and will interchange.

Do you know why the Model DHB wheel has different static load ratings. Is there really a difference in design or metallurgy?

Dennis

Paul Agaliotis · Post by **Paul Agaliotis** » Thu Oct 16, 2008 12:51

Dennis,
To me the DMB wheel is made with a different alloy or proceedure than the DHB wheel. I have never done any comparison other than side by side.
Most of the airplanes out west have replaced the DMB wheels with the higher gross weight models.
Paul

Post by **joea** » Thu Oct 16, 2008 13:30

The Goodyear wheels are the same. They "appear" to be the same yet some are stamped with a 1000 pound capacity, while others that appear to be exactly the same are either 1200 or 1500 pound versions.

The Sedan and Stinson Voyager both had the 1500 pound versions. If you have the choice I would use the higher weight version wheels and hope that this helps with cracking.

Joe A

flyingfool · Post by **flyingfool** » Thu Oct 16, 2008 16:18

Ok it is OT but.

I have goodyear wheels. I gather from this thread that there is a problem and possibly an AD on the wheels cracking.

being new to owning a chief. What is the problem, and how is it inspected for? Does it have to be done at each annual? What do I and my A&P look for etc.

SFC Hiatt · Post by **SFC Hiatt** » Thu Oct 16, 2008 16:22

48-08-02 AERONCA, CHAMPION AND SILVAIRE: Applies to all Aeronca 11 Series, Champion (Aeronca) 7 Series, and Silvaire (Luscombe) 8 Series Aircraft Equipped with Cleveland Model 6:00 DMB Wheels, Assembly No. C-38500.

Compliance required after initial 500 hours of operation and each 100 hours of operation thereafter.

Remove the tires and inspect the wheel flanges for fatigue cracks. The wheel should be replaced if cracks are found

Dennis · Post by **Dennis** » Thu Oct 16, 2008 16:25

Well crap!!! I guess I should use my glasses more. I thought they were all the same model. Now it makes a little more sense.

Thanks Paul, I'll look a little closer.

Dennis

Post by **joea** » Thu Oct 16, 2008 16:26

FF,

There is an AD on the Cleveland wheels but not on the Goodyear wheels.

Still, they need to be taken apart and checked at every 100 hour or Annual, or when you are concerned about them. The other big issue on the Goodyear is the clips. They have to be all on the wheel and disk and in good condition. If they pop off and are not replaced airplanes have been known to lock that wheel and either ground loop or flip on its back, so this is not something to be taken lightly. Most of us use silicone to hold them into place and check them before EVERY flight.

Both crack from time to time and as they are at least 60 years old are worth keeping an eye on.

Joe

Nathan K. Hammond · Post by **Nathan K. Hammond** » Thu Oct 16, 2008 23:33

I'm with Paul; 28*-32* so it rolls easier on the pavement and grass.

nkh

jkvincent · Post by **jkvincent** » Fri Oct 17, 2008 10:31

I spoke to Specialty Tires this morning about these Pressure listings and they said,
...these are the recommended inflation rates before the wheel in mounted on the Aircraft.
Jim
P.S. ...don't shoot the messenger

Roger Anderson · Post by **Roger Anderson** » Fri Oct 17, 2008 11:38

delete

Post by **joea** » Fri Oct 17, 2008 11:46

Like Roger, I need no help in bouncing during landing, so while I may try to increase pressure higher a bit just to see what its like, but will probably stay in the lower ranges.

I fly off of hard surface 99% of the time, and bouncing can lead to ground loops so this is something that none of us need.

Joe

jkvincent · Post by **jkvincent** » Fri Oct 17, 2008 13:49

Roger, you can put what-ever you want in them,
that's not my "interpretation" of the chart, it's what they (Specialty) told me.
The chart was an attempt to give folks "hard" information.
Yes, it's nice to know what everyone is actually using, but it's also nice to know what the Tire manufacturer recommends.
I agree with the assumption that if you only carry 1/2 of the designed Max load,
then you should be OK with only 1/2 of the recommended pressure.

Personally, I have 7.00's and they don't have 38 lbs. in them.

Like I said, don't shoot the messenger.

Jim

Roger Anderson · Post by **Roger Anderson** » Fri Oct 17, 2008 17:23

Jim,

My sincere apologies. If it appeared I was being critical of either you or the chart, or was shooting the messenger, I certainly did not intend for that to be the case. I was only tossing in "opinions" again...something I'm very bad about doing...probably brought on by the 34 years I worked for the FAA. I intended it to be in only a fun type manner, not that of criticism. Not being able to shut my mouth, my Chief 11AC service manual, in the preflight section, does say specifically to "check tire pressure between 13 - 15 lbs". I'll withdraw myself immediately from this and again am sorry.

Roger Anderson