preserving tires on aircraft

[old chuck]

What do you use to preserve aircraft tires when the plane is stored outside? The tires were filled with smackmammy to keep them round, but are still sun burning.
Old Chuck at War Eagles Air Museum

[Bill Greenwood]

The best thing is to cover them with canvas or something to keep the sun off.

What is "smackmammy"?

[old chuck]

Bill,Its some "stuff" that you can put in a tire so it does not go flat.You dont have to add air
all the time.This is on a F84 we are getting ready to restore.thanks,,,chuck

[Jerry O'Neill]

One thing about the stuff you fill the tires with.
If you intend to move the aircraft around a lot, don't fill them with that rubber substance. It's okay for sitting and some movement, but the NEAM's FM-2 had the fill done years ago and since then, they started to bring the Wildcat to some events. After a couple of years, the tires quickly self-destructed.
The best thing is to keep them out of direct sunlight and have the aircraft on stands so the wheels don't touch the ground.
Jerry

[Keith Gaff]

The best you can hope for with tyres is to slow the deterioration rate. Rubber, in common with several materials, suffers from a phenomenon known as inherent vice. No matter what you do; eventually the rubber will deteriorate. As advised, keeping the weight off the tyre and shielding the rubber from ultra violet will greatly slow the process. Another trick to stop deterioration, especially within the tyre, is to inflate it with nitrogen, rather than air. No oxygen means no degradation. One word of caution. If you are going to put an aircraft up on wheel stands do not bolt the stands to the floor. Aircraft structures expand and contract, almost imperceptibly. If they are constrained in any way you are going to set up stress patterns in the airframe and you will get cracking in fittings or the airframe itself.

[shrike]

I ran into this question when I used to play with old cars. There it was more the preservation of old bushings etc. instead of tyres but the basics would still be the same.
I asked around to all of the manufacturers I could find to get some consensus, and, after advice to keep things cool, out of the sun and away from sources of ozone (2 out of three won't apply in this case) the most common answer was using a silicone dressing similar to "Black Magic" brand. It's formulation is close to the silicone oil used as a mould release in current tire and rubber making, so it won't harm the tyres, provides at least some UV protection and slows down loss of volatile compounds that lead to hardening and 'dry rot'

[Clifford Bossie]

Chuck - Do you think there is interest in placing jacks under the F-84 when we are finished?