Big tires on a 9

[Greg Arehart]

I finally got all the ducks in a row and got my new tires on the RV this weekend and did some test flying. After the engine failure, I decided to transform my 9A into a 9, and meanwhile, get some bigger axles. So I ordered custom axles (an inch longer than standard) from Harmon Lange (and a thanks goes out to Richard, who built them and worked with me on drawings and getting legs aligned etc.). I took off my standard Cleveland setup and bought two sets of wheels from Matco (another shout-out to George Happ at Matco, who was most helpful in making sure I got this order right the first time). Both are 6-inch wheels. On one set, I put some 4:00 x 6 tires, which are narrower but virtually the same outer diameter as the standard 5:00 x 5 tires. The second set is 8:00 x 6. Both wheels use the same Matco brake setup and changing from one set to the other is simply unbolting the wheels (three bolts) from the brake disks and swapping out the wheels (they use the same disk). No messing with changing brakes etc.

So, how do the new setups land (they fly about the same, though the bigger tires are more draggy and don't fit into the fairings)? I honestly can't tell much of a difference in the landing characteristics between the 4:00 x 6 and the standard 5:00 x 5 on asphalt. The 8:00 x 6 tires (running about 13 psi) land VERY smoothly (again on asphalt only so far). In terms of visibility taxiing, there is slightly less visibility with the bigger tires, but not a lot less - certainly not as different from the "standard" view as I had expected.

The obvious question is why fix something that isn't broken. My answer is "because it's experimental and because I can!" Actually, I will be flying north again this summer and having the taildragger plus the bigger tires will allow me to get into some places that I wouldn't otherwise want to take an RV (but I have no illusions about this being a super cub either!).

I have not done the tests yet to see how much the big tires are going to affect my cruise speed, but the goal really is to fly most of the time with the small tires and fairings, so no speed loss there. When needed, I can just pull the fairings and swap tires. No, I don't plan to always carry the big tires most of the time, but will be using them when up north this summer. I've also built some gravel deflectors that bolt onto the axle and fairing flange.

Will post some photos when I get decent ones. I took some with the iPhone, but they didn't come out very well.

And here I thought I was done building airplanes a couple years ago when I got the pink slip....

Cheers,
greg

[sbarger24]

Very cool Greg! You must of have gotten a lot done this morning