It's an odd combination, but it works EXCELLENTLY well.


The Tiger 60 has a bit of a clearance problem if you fly it with tricycle gear and especially if you fly off grass. I fly off of 3 different fields, all grass, and 13" worked best. 14" would work but was always knicking tips and those props ALWAYS carried a load of grass crap stuck to them. My models seldom need fuel/oil residue cleaning since I use extensions, but I was having to clean the crud off those props every couple of flights! PITA

When I tried 3 bladers, the Graupners I tried had too much blade area. They took a bit to wind up, but lost rpm every time they were loaded. In other words, vertical suffered and you could hear the r's drop off going over the top in loops. Too much blade or pitch or diameter will do that. Our glow engines have a relatively flat power curve, and once they're up into it, can handle a pretty wide range of props. But I never found a Graupner that fell into that range.

I tried Master Airscrew's recommended 3 blader for .71-.90 expecting that it'd also be too much, and was I surprised. They say to use an 11x8 (3) and I could find one. And it was nowhere enough prop. I had a 12x8 (3) that I'd tried on an OS91FX that hadn't been enough prop for it too. It was what MA had recommended for .90-1.08 and I'm running 14x7(3)s on 4 different OS91FXs on 4 different models with EXCELLENT performance, so I figured the 12x8(3) eventhough "too much" according to the mfg, should be at least OK. It wasn't enough prop either.

The prop you see in the picture is a 13x8 MA. Master Airscrew says it's best on 1.08-1.5 engines. I haven't found their advice to be worth spit. Nor have I found conventional model airplane wisdom to be worth spit when it comes to 3blade props. I don't think it ever was close to right because I've been seriously flying models since the 50s and never saw but a very few 3bladers ever used, much less for sale and readily available. Truth is, I can count on one hand the times I saw 3bladers for sale in LHSs back when there were lots of big LHSs. whatever...............

The Tiger60 you see get's a lot of work. Matter of fact, it'll be in the air in a couple of hours and will be up again on Friday, and this will be a slow week. The OS75AX on it has been a bull since day one. It's had a 13x8(3) on it for at least the last half of it's life. The Tiger and it's 75 started life about this time last year. It is a very good flying combination. All three combined.

I almost always wind up with "a lot of prop" on my models. I really like fan area. So for sure, my planes will have the most prop diameter their engines can swing. That often means that the engine can be heard to unload just a bit more slowly after takeoff than the average modelers' engines do. Ain't no big thing, but don't expect to tach big numbers on the ground. After all, we don't use our engine's ground performance. We use the performance in the air.

I've also run a 12x8(3) MA with decent enough success. But my prop testing includes a set of timed vertical climbs, and the 12" never hauls the load straight up that the 13" does. Fan size is probably the reason.

BTW, I never bother with hotter fuel than 10%. No real value.

Hope this helps.