jaka

Hi!
As some of us have said before...four OS wankel engines will be way to much for the Marutaka B-17. They will produce too much power, add too much weight and not be reliable enough.
I have been R/C flying for 35 years, 30 of those years competing in pylonracing, constructing my own models, both sport and pylon and it's my experience that many newbies tend to put in way too large engines in their planes. I like speed or more precise, competiton around the pylons...for speed is nothing! Flying fast is easy. But I want my scale planes fly slow and graceously as the full scale original and to do so I have to build light and choose small (with adequat power) and light engines.
If I was to fly fast I would not choose a B-17...I would go for a pylonracer.

From experience I know that 2,5 or 3,5cc engines is just perfect for the Marutaka B-17...or OS .26 fourstrokes if you want to have a little faster plane.

Throttle down is no option if you want a nice flying scale plane!

Regards!
Jan K

I-fly-any-and-all

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I-fly-any-and-all

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Fyra o.s. wankel är motorer inte över dödar för kunglig/marutaka b-17. Jag har fått en kompis som flyger en med fyra o.s. .32's. Ya runkare.

LOL


oh crap

Thisstrangeengine

Just my input on the Wankle engine. I own one and ran it in a single airframe and it is a fuel hog; not to mention it spews oil everywhere! I love the sound of it but the carb is an air-bleed type and the only adjustment is the needle valve which is probably why some find it unreliable. I never tried fitting a different carb but others may have. I just put after-run oil in it and put it back in the box for safe keeping with no future plans for it other than to say I have one? [sm=50_50.gif]

I-fly-any-and-all

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is the person who started this thread going to ever return and post?

I-fly-any-and-all

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This is nuts! I bid on two royal b-17's on flea bay and lost the first one due to last minute bidders so ok...
The second one I set my max bid as $700 and then hoped for the best. luckily for me some fool bid $710 at the last second and saved my behind.

Read more: http://www.rcuniverse.com/forum/m_66...#ixzz0rYCvqZ3o

zdsh13

Yikes..... I found mine on RCU for an ok price $315. Then again thats more than what the kit cost when it was in production Now I just have to find some time to open the box and build it.

peternj

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hi all, just got my hands on a B-17kit... but it's in prestine shape so I was wondering if any one knows where i can get a short kit for it?

I-fly-any-and-all

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A short kit for the royal b-17...
http://www.kitcutter.com/cut/www.kitcutter.com/

he used to cut them but he's gone. look here for help: http://www.rcuniverse.com/forum/m_66...m.htm#10472990

I-fly-any-and-all

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Any more progress on the b-17?
I picked up a bui8lt royal b-17 with most servo's minus aileron servo, and 4 royal .25's for $250 but needs a little work. other royal b-17 has yet to be built.
also snagged a royal b-25 with flaps, retracts, and two os .46's for $375.

jaka

Hi!
Those .25 Engines are too Heavy and too powerful. If you want a nice flying B-17 ,A better choice is using four OS LA.15 Engines and 8x5 APC props.

Bob Paris

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Aloha ...I-fly-any-and all,
Yes I've heard of restraint use of the throttle, but the weight of the engines, plus the large amount of fuel needed to feed these larger engines, kind of...in my book, takes away from the over all performance of the model. Royal kits do not build light...more stout and strong then today's ARF's and a bit heavier too. I built my first Royal B-17 with the Fox .15's and was very happy with the performance. I've another kit and plan on building it with OS .15's. You do not have a lot of room for fuel tanks and if you use retracts, the two inner engines (#2 & #3 engines) will have even less fuel. You can add all the scale you want to the kit, but as the weight adds up, just adding more power, kind of takes away from the flight envelope.

I'm not a curb kicker...I've been in this hobby for over 60 years and I've built a dozen or more Royal kits. Light weight scale models with proper power fly very nice...to include most all Royal kits. We have a club member here that is building a Top Flight DC-3 with Wankle .30 engines. I've had four of these O.S. engines over the years in models and I'm very impressed with their performance. The wind-up from idle to full power is unlike any other glow engine I've ever used, and almost instantaneous. The only draw back I see in the engines is the fuel draw...its a .30, but uses fuel more in line with a .60. If you run the engine lean just once to hard...you will need a rebuild...ask me how I know.

My report is just an observation from experience in Royal kits. The Royal B-17 will fly quite nice with any .15 ~ .19 glow engine. I've help build two and owned two over the years...how many have you built and/or flown? If you need statistics...just talk to O.S. about their engine, or any one that has any real experience with this engine and the Royal B-17 kit.

Soft Landings Always,
Bobby of Maui

I-fly-any-and-all

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I should have stated I pulled the four royal .25's and have four os .20 four strokes all rebuilt going in it for power. I do however plan to test fly it as is. I talked to Scale dail and his uses the high performance os .15 CVA engines and has retracts and flaps weighs around 15 pounds! wow that's a piggy for a 77 and 3/4 inch bomber, but he said she fly's. For use of bigger tanks I could go the route of wing MFG and put a tank in the wing and a header tank in the nacelle with the retract.

Bob Paris

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Aloha, I-Fly-any-and-all,

Four .20 four strokes will be a great match for this model. They do have a bit of weight, but you will be able to spin a larger three blade scale prop for yourself. Four strokes have a really nice note and four will just sing for you.

Header tanks work well in helicopters...and if you mount a larger tank in the center part of the wing...and run four lines from one fuel tank...or two smaller tanks and run two lines off of each tank...it just may be the way to go. I just used Sullivan clear fuel tanks and after warming them up...force the largest tank into the nacelle I could. I'm currently building an AMR Twin Ugly Stick, with twin 35cc gas engines and have a 32 oz. center fuselage fuel tank, running out to header tanks in each nacelle. I also have a small fuel (smoke) pump to run fuel out to the header tanks, and over flow vents onto each nacelle tank-incase I over fill the fuel tank. I've never done this before and this is my largest kit I've ever built.

I wish I had a set of Robart retracts for this model, but so far unable to buy a pair. The Royal B-17 has a huge wing for a scale model and fly's on a wing, just like the original one. It is a different kind of r/c flying then most folks do today...with all the high powered aerobatic models available to the modeler. You will need to do a bit of a take off run and build up your speed, then let the model fly off the run way. I plan on buying four O.S. .15 CVA engines for my last kit and I've them located to purchase. These engines are hard to find today and are not cheap. These O.S. .15 CVA's, are with out a doubt, one of the most powerful .15 class engines ever produced. Fox's little .15's were real screamers too...but not as dependable as O.S. were. I lost my last B-17 with Fox engines on board...lost two on a side and it was a slow motion re-kit. I've one more Royal B-17 kit left and I'm looking forward to the build. I also have the cockpit kit for the model and I've had this kit for 30 years.

Do post pictures of your build and looking for ward to you project.

Soft Landings Always,
Bobby of Maui

I-fly-any-and-all

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how is progress on the royal b-17?