What luck, I went into my local hobby store on my lunch brake today and they had one last excelleron 50, not only that but I ran into a guy who sold me a nib OS FS-91 for $120. My question is will this engine work out in this plane or will it up the wing loading too much. Does this plane require lead in the nose to get it to balance out anyways? This will be my first quality engine so I'm really hoping I can get it to work out.

Nevermind, according to specs on the box a 70 sized for stroke is the top range. There is only one ounce difference between the OS 91 and OS 70 so I should be ok.

Jeff, the OS91 is way too much power and way to heavy for that plane. The regular OS 70 4-stroke is already very nose heavy on the plane. There is a lightweight version of the OS 70 4-stroke that is the absolute maximum as far as weight is concerned. My 11 year old son has 2 Excelleron 50s. One is powered by an OS55AX and is great. It is currently his practice plane. The other has a YS63S on it and is awesome. He is not flying it right now as it is his contest plane. Both are a bit nose heavy with the YS being a bit more so. Your 91 Surpass will make your plane a bit more difficult to fly and hotter to land. I strongly suggest you trade it for either a YS63S, an OS 70FL, an OS 55AX or an OS 50SX in that order. Just my 2 cents worth.


Jayjay

bummer, guess it wouldn't go very well with my gms 47. Looks like I'm going to have to buy the OS 55AX, and save the fs91 for my future top flite spit project.

Hey guys, I'm also getting ready to put one of these planes together and am thinknig of going with one of the newer Thunder Tiger 4 strokes. The 75-s seems to be a great match for the plane but the I think the 91 might make it a bit faster. The 2 engines are about 8onces apart, the 75 at about 16 and the 91 at about 25. What do you guys think about my dilema? Do I need that extra power of the 91? Also what are your planes weighing in at? This is my first Pattern style plane. I'm a 3D guy so i'm use the the cg being way towards the aft. How do you tipically set the cg on a pattern ship? Thanks for the help fellas. Scott Hall

No the weight penalty is not worth it, especially since it should be amply powered with the TT-75. You scare me when you ask about speed- This is a pattern planeLOL

Seems also, by the above older posts, that the CG will be hard to hit even with the 75- makes this an easy decision.

If it flies anywhere near the bigger Excelleron, then you are in for a treat!

Thanks for the info Razor. Yes it's a pattern plane but pattern planes can fly fast. What you said backs up what my gut was telling me. Hey by the way my grandpa lives in Romona. He has a buddy that flies. You might know his buddy but I don't know his name. My grandpas name is Bill Stromberg. Anyway thanks man.

Scott

I've been flying my Excelleron 50 for a couple months now and I love it! I am just a sport flyer but I like to make up my own pattern and fly the plane rather than let them fly me, if you know what I mean. My Excelleron 50 has had an OS FL-70 during most of that time but i recently replaced it. I think it was getting messed up somehow by the weird soft mount system that comes stock in the ARF. That stuff seemed to let my engine vibrate more than hard mounts, and seemed to shake the engine to death. Anyway, that is another story, and I just in the last few days put a Surpass 70 II in the plane on hardwood engine mounts. I hated to add weight (about four ounces all up) compared to the FL-70, but my son has the same engine and it runs like a champ all the time. I just got done installing it and will fly it this weekend. Prior to this, the engine could slow down to a walk to land, yet really zip at full throttle. There's some coupling caused by the rudder in KE, but I have gradually mixed it out with some elevator and aileron. Great airplane, my fave now, even over my CG Ultimate bipe with an OS 120 Surpass in it. BTW, my all up weight is 6.6 pounds with the heavier Surpass II in it. (I weigh the plane with me with my human scale, weigh myself again immediately, and take the difference.) Some of the trim covering needs to be CA'd down because pointed edges on the stars and other areas want to peel up. Oh, the FL-70 gave the plane unlimited vertical as long as you controlled the assent with rudder and elevator, while the engine was newer and strong. I expect the Surpass II to do the same if not better. Good flying, Jon

It's really not advantageous for a pattern plane to go faster than necessary. You don't get as much time to think about what you're doing and it makes your sequence look rushed and lacking smooth flow. In pattern, precision is king.

Just an update to my last post about 10 weeks ago. The switch I made to the OS 70 Surpass II has worked well for me. I had to add a little tail weight since the Surpass II is heavier than the FL 70, but it was worth it. I have been having a ball with the Excelleron 50 and OS 70 Surpass II. The engine is purring now and has unlimited vertical as long as I keep her straight up with the rudder and elevator, as anticipated. She is just so stable, flies fast when needed, and slows down for perfect landings. Speed envelope is very wide. Been able to learn rolling circles (roll to the right for a left circle). I love this plane! The only fault has been the stars are peeling off after so many flights! Jon