91 4 stroke for SPA
 

In checking out various SPA setups, it seems most go with a 91 4 stroke setup. It also seems that most use OS 91s. I'm curious why more don't use the Saito 91 as I thought they were supposed to be a little more powerful and a couple ozs lighter?

RE: 91 4 stroke for SPA
 

Dave

There are a couple of Saitos and they run fine. Peer pressure, I guess. The weight is a good point. Most SPA planes have a balance issue when using the OS 91. Stretching the fuse just a little is a common fix. Going to a tail-dragger configuration helps, too, and is allowed within the rules.

RE: 91 4 stroke for SPA
 

Has anyone tried a Saito 82a? This engine is actually lighter than many 60 2~strokes.

I just got one to put into a 3D plane but this thread got me thinking about power/weight as I have 2 planes to build over the winter. Maybe I'll try the Saito in one.

EXCAP232

RE: 91 4 stroke for SPA
 

Looks like it might be a good choice. The HP is .1 less than the OS but much lighter at 17.6 oz compared to the heavy OS that is whooping 24.2 oz. I’m not a big fan of four strokes, but for SPA flying the Daddy Rabbit with an OS 91 is the standard pattern ship.

RE: 91 4 stroke for SPA
 

The variety of planes at Knoxville was a little greater this weekend. 4 or 5 Dirty Birdies, about 8 Intruders, a couple Curares in addition to the Rabbits.

RE: 91 4 stroke for SPA
 

EXCAP232

The 82 is nice, but I believe the 91 is actually lighter. has same case dimensions.


DM