I got a flat tire on my airplane and, while I was fixing it, I realized that airplane wheels are kind of odd, at least compared to car and motorcycle and bicycle wheels. So I figured I would share some photos.
First of all, I had to negotiate access to the wheel with its resident amphibious guard.
The little guy grumpily hopped away when prodded. As soon as I turned my back, he returned and took up residence underneath the tire, next to the jack. I shooed him away again since I really didn’t want the little fella to get hurt if I accidentally dropped a wrench.
Removing the wheel is easy. Pull out the cotter pin. Remove the giant axle nut. Slide the wheel off the axle. On the bench, it looks like this.
The tire size, 15 x 6.00-6 is 15 inches in diameter. It’s tread is 6.00 inches wide. The wheel is 6 inches in diameter.
Most of the wheels that we deal with these days are one piece. They are either cast aluminum or stamped+welded steel. Airplane wheels are made in two halves which are held together with nuts and bolts. You can see the three lock nuts circled in yellow in the picture above.
Start by letting the air out of the tire by removing the valve stem. (I did not have to do this step because the tire was flat when I took it off of the airplane.) When you remove the nuts and slide the bolts out, the two halves of the wheel come out of the tire and you have this on your bench. The wheel itself is cast aluminum.
Changing the inner tube is just as easy as changing the inner tube for a bicycle. You start by sprinkling some talcum powder inside the tire and rolling it around. This reduces friction and chaffing of the tube. Then you mush the uninflated inner tube into the tire, add enough air so that it pops into place, and it looks like this.
The valve stem (circled in red) goes through the hole in one half of the wheel (also circled in red). Then you insert the bolts and tighten up the nuts and voila the job is done.
As long as I had the wheel off of the axle, I repacked the bearings using a run-of-the-mill bearing packer tool from the aviation aisle at O’Reilly Auto Parts.
Total time to do the job was well under an hour, not including the multiple trips across the airport to get the right size inner tube because silly me bought the wrong size online and to get some talcum powder because silly me left mine at home. Silly me.
VERY INTERESTING, AS USUAL!!!
Ruth
I love aviation explanations which relate to vehicles I understand, and the pictures are a perfect accompaniment. The frog really makes this! Even explaining apparently simple stuff like a tube change is worth it, so please carry on doing that, Art.
I’m happy to oblige 🙂
The frog looked dizzy to me…. I wonder why??
Great article!
Art, great write up but one safety note that you did not mention. Safe practice with aircraft wheels is to always deflate the tire before removing the axle nut. If the through bolts are fractured (rare but possible) they could fail and the wheel would explosively disassemble itself and embed the nut and other parts in anything in its line of travel (think you, especially your face or chest!)
I remove the valve core, tools are readily available in the next aisle over at O’Reilly Aerospace Supply.
Cheers
Jim,
So true and thank you for the reminder. I did not have to deflate the tire because it was flat when I removed it from the airplane. As a result, I forgot to include that step in the article. This is a very important safety point. I have corrected the article.
— Art Z.