My modified LT-40 with flaps is ready to fly. The bomb bay pushed the servos rearward and the .56 Saito doesn't quite balance it up front. I found a weighted spinner at the swapmeet that nearly balances the airplane. My question (this is my first four stroke) has to do with the locknut. Do I put the nut/locknut/spinner combo on all together or do I use the spinner as a jam nut against the primary propeller nut?

Thanks,

Greg

Use the spinner as the Jam nut. I've flown a Saito .56 with a CBI associates spinner adapter in place of the lock nut and not had a problem for many flights. Just put a wrench on it periodically and make sure it's still tight, you should be good.


Andy

What prop are you guys using with your 56's? I've tried everything, and they all seem about the same to me (I've tried 11 x7, 12 x 5, 12 x 8). I had a 12 x 8 apc, but that was too much. the 12 x 8 mas will turn ok, but I'm only getting about 8-9000 rpm. the 11 inch props give good rpm's (about 12000), but still seem small. I literally wen through about 4 or 5 props yesterday trying to find the best combo for this engine. I'm fixing to put this engine into a contender that I'm building, and want to get as much speed as possible. I know this engine is not a speed deamon, but I think it's capable of more than I'm getting from it right now. I'm running 15 % fuel right now. Would an 11 x 8 apc give me any more? suggestions????
Sorry, didn't mean to hijack the thread, but since we were talking saito 56's....

DuBro makes a weighted washer designed to go between the prop and nut, comes in 1/2 oz, and 1oz. sizes. I use the 1 oz underneath the adapter nut for my Dave Brown aluminum spinner, also on a .56 Saito. This is on a Rascal 40, which gained some tail weight after a crunch and rebuild.

As far as props for this engine go, I started out using a 12-5 MA K-series on my 40 Rascal. It would turn 9800-9900 on 15% fuel, but my airspeed wasn't quite what I wanted, so I tried a 12-6, it only dropped rpms about 150 and gave noticeably better airspeed and climb performance. I'm planning on putting this plane on floats next summer and want more thrust, so I've tried a 13-6 MA. The plane really hauls, now, not much faster than the 12-6, but a bunch more vertical performance, which tells me more thrust; the downside is that it eats the rpm, dropped it to about 8200 and slows throttle response a little, takes more power to spin the prop. My next step is to try a 12-5 or-6 three blade to address the thrust issue, and I'm also going to try 20 or even 25% nitro and see what happens with power. Personally, from all the flying I've done on the Rascal, I think the engine is happiest with a 12-5 or 12-6. Of course a different style prop could give different performance, such as a APC. I also think that the weighted washer has a small mass effect, even though it is close to the center, there is a small inertial component that slows the engine's response.

Thanks for the ideas! I have not tried a 6 pitch prop yet. I've tried 12 x 5, but like you do not like the performance all that well. I've tried a 12 x 8, but can't see that much of a difference in speed. Maybe because it's loading the engine too much. I'll try the 12 x 6 and see what happens! Thanks a lot!

I had the same problem on an OS 91.I used a brass domed nut and counterbored it so that it covered the manufactueres nuts to give a better look.
Mack

I have a Saito 56 on an H9 Cub and I needed a ton of nose weight. I used a Harry Higgly brass prop nut, with a HH brass lock nut... don't know if I'm using the right name.

Basically, mount the propeller, and install the HH lock nut. It's a thin brass nut, but large diameter. Uses a 17mm wrench IIRC. I tighten that lightly, then install the large heavy prop nut. I tighten that up against the lock nut. Works great. I've never had a problem, and I don't use the Saito prop nut or washer at all.

I use a 13x5 MA K prop on mine, and get about 10,400 max rpm, and then richen it up to 96-9800. I'm a little surprised that you guys aren't getting more RPM with those 12x5's.

I recently tried a wooden 12x6, and I think I like it, though I'll have to test more. Definitely winds up faster than the 13x5 MAS.

Same here. All my enegines have the small solid starter cone and thats all i
use to hold the prop on. Do check for tightness quite often. Never had a problem
yet and have been using them evey since they come out.

Thanks for the good info. Answered my prop question too!
Greg