H5487

The plane in the picture isn't mine but it's a good representative of what I'm planning to build. The plane is a Super Rocketeer and was designed in 1947 for free flight. The plans are currently available (from Bob Hollman, and "bw240d" on e-bay) in the original FF version, or adapted for R/C. I'll be building the R/C version with rudder, elevator, and engine control. It has a 58" WS; its finished weight is unknown but I'm estimating 2-3lbs. I plan to cover it with silk and dope.

I'd like to get an estimate on what size 4-stroke nitro motor to plan for. I'm not shooting for a 3D performer, just a nice and relaxed end-of-the-day flyer.

I already have the plans in hand and the short kit (from Bob Hollman) is already on its way. Any suggestions as to motor size and/or other advice is solicited.

This isn't my first build.

Thanks,

Harvey

Bax

My Feedback: (11)

Likely a .25-size engine or so. Maybe even a .15-.19 would work. That plane is basically a glider with a bit of power. You use the radio to provide enough "interference" to keep it within range of the field.

H5487

Thanks Bax. Perhaps a .30 Saito 4cy will fit the bill. (By a remarkable coincidence, I happen to have one looking for a job!)

Harvey

JohnBuckner

My Feedback: (1)

The best possible combo for that airplane if you can find one is the OS FS 20 they are much sought after for an old timer in that size. Even the OS FS 26 but personally I would avoid the he thirtys either the magnums (I owned two of those and both were a disappointment) or the Saito 30's.


John

buzzard bait

Especially since you have one, a Saito 30 sounds like a great choice.

JB, why don't you like them?

Jim

JohnBuckner

My Feedback: (1)

If you mean the Magnum 30's that I was referring to they were awful and sounded just like a running clothes dryer with nothing in it except and old pair of tennis shoes. Used a new pair in one of my twins for a while until I could not stand the noise anymore. The were quite reliable and never quit but not my cup of tea. Changed them out on that airplane for a pair of OS FX .25.

As far as the Saito thirty thats an entirely different ball park and happen to have a new one just waiting for the perfect airplane.

As far as the op's airplane goes I think any of the .30's is to much weight/physical size. Still believe the ideal on his ship in a four stroke would be the OS FS 20, just one mans opinion.

John

buzzard bait

It depends on which Saito 30. The oldest one was heavy for its size and not very powerful, but the current one, which has been around for a long time, is slightly lighter than the OS 26 FS when both are equipped with their mufflers, only 9 1/2 oz. I think it's a terrific little engine, and I think it would be great on that airplane.

Harvey, that's an awfully nice photo you found.

Jim

H5487

Yeah, it IS a pretty thing isn't it? I got the picture from an eBay site that's selling copies of the original FF plans for the Super Rocketeer (seller "bw240d"). I bought a set of plans from bw240d before discovering that Bob Hollman's plans were already updated for r/c. In addition, Bob sold a short kit for the Super Rocketeer. I ended up buying a kit from Bob as well as a second set of plans (in case Bob's kit differed substantially from the plans that I bought from bw240d).

Thanks for the inputs guys. I DO like the idea of putting a four stroker on a vintage design but I'm also starting to think that maybe a Saito .30 might be a tad big. (I'm not a proponent of overpowering!) I like John's suggestion of an OS .20FS but they're a bit difficult to find nowadays. And buying a used one off eBay is kinda like Russian Roulette! I might look for a small (.19-.29) ignition engine for the plane but, then again... potential eBay Roulette!

My fall-back plan will probably be a Saito .30, of which I actually have two. One is a "recent" .30 but the other one is an older "open-rockered" .30 that is probably comparable to a modern .19 or .25 two-stroke; thus a good choice for this plane. However, that early Saito is kind of a display engine that I don't really want to risk damaging.

Maybe I'll put an electric motor on it......................NOT!!!!!

Please keep the suggestions coming.

Harvey

buzzard bait

Another idea would be a K&B Sportster 20 (or maybe 28) which can be found on ebay quite cheap if you are patient. The 20 can swing very large props without over heating. I know this because after reading about Stu Richmond running a 20 on a 12x6 (not a typo!) I bought one and carefully broke it in on all-castor oil fuel and worked my way up from a 9x4 at first to a 12x4. It ran smoothly and quietly on the 12x4 and throttled fine too, making 7350 rpm at full throttle. I didn't try going to a higher pitch. It was good on smaller props too. I got 11,000 on an MA 10x4 G3, and on a Zinger 11x4 I got 9150.

I have run diesels on some of my planes but tired of the smell and mess. I still have some small diesels which I don't mind. I think the Sportster 20 is a good alternative to a diesel in that size. I image the 28 would be fine too, but I don't know.

Jim