Finally got a chance to fly my new ROTO25.
I put it in a Cermark Pitts -all up 12.3 lbs - I put a big 2700 ma batt on the rear wing mount crosspiece -which balanced it 1/4" ahead of the instructions - - Just right but not really light.
Anyway I used the stock super silent, tiny muffler - and a 16x8 APC prop .
fuel is Mobil X 2 whatever --at 32-1
It is all new - and the on the ground tach was 8250 and after the first flight , I read the max rpm tattletale LED--it had gotten to 8340 rpm in the air -but that was from just one short WOT flyby.
The muffler is very restrictive -but oh so quiet.
I put a APC 16x10 on it afterward and it ran at 7700-on the ground -
The instructions on the kit said " gasoline engines vibrate a lot-so make a strong structure etc.".
I used the kit plastic mounts - the engine easily bends themount up and down-if you push on the spinner - BUT when running at any rpm there is NO spinner movement except for spinning
I was really surprised. perfectly smooth
The combo is not a competition setup and the hover stuff is out of the question - but it really does all of the forward motion maneuvers very well -I ran thru a couple of rollers -huge loops hammers etc .
Really a smooth runner and now I guess I will stick a little pipe on it .

Nice to know it flies well with a small gasser. I just picked up an older one NIB and was looking at the G26 for it. I'm not interested in the 3D stuff with this plane, just nice "Normal" aerobatics. Keep us posted on how it goes.

Hi Dick
I have been reading your post regarding the roto 25 i bought one in June this year when it came it had a carb that had the return blocked off,the engine did not perform very well, calling RCS they explained that it had the wrong carb on it and sent a new version it's the same one on my RCS 44 CC twin which runs very well replacing the carb on the 25 and adjusting the needles I found the running really improved i am spinning an 18x8 master airscrew prop the engine is on a hanger 9 edge planes really moves but i have a midrange cut out problem and if i adjust the carb so this does not occur i have no top end and the plane won't fly it almost stalls in the air have you had any similar conditions.

Rg's
Dennis

you are overpropped - switch to about 16 -10 then see how it responds .

Hi Dick
I can not find out where i have seen your old post on Roto 25 and Funtana 90[]. Could you give us a short story about that combo?

total weight?
tuned pipe performance?
RPM with 18x8, 17x8?
Should i modify the engine box to support vibrations ?
Would it be possible to hide the pipe under the fuse by building a balsa box over the pipe?
Can it hover at 50% throttle[>:]
thanks
Daniel

Dick: I'm looking really hard at this engine for a PMP Extra 260 - no 3D stuff, (the model is IMAC pre-3D), just pattern, although with an AUW less than 11lbs.... The model is tunneled nicely for a pipe, I was wondering where you got the CF pipe for the Roto (reference earlier thread), and the header pipe (best length)? Some contact info would be great.

Thanks.
Roger

The Roto 25 I setupwith one of Ed Skorpa's carbon fibre pipes . ESCOMPOSITES
I did not tune for max power -but for a throttlable performance.
the prop I used was 17x6 and ran it around 9000.
IF I use the in air readings the rpm goes way up( engine has a tattletale tach - these guys are way ahead of the crowd on this feature.)
I di not use big props as this was a 3D model and the prop NEVER unloaded much at all -I held speeds very low.
The pipe weighs 3 ounces.
Nobody has anything like it-so tuning lengths would not relate well.
The all up weight was 10 lbs and it took most of the power to to pull away from a hover .
The smoothness was a big factor in using this setup - I beefed up nothing on th model -as it works with 1.2-1.4 YS engines and these can shake far worse.
Power is about (sorta ) like a 1.2 fourstroke YS. So tho the setup will work -it is not a slam dunk , bolt it in n go 3D setup.

Dick, I have a Roto 35 in the mail. I plan on installing it in a Lanier Ultimate Pitts. My big concern with this motor is noise. Our club has strict noise limits and if doesn't pass it won't fly. I plan on installing a 3 blade prop. I was looking for an after market in-fuse canister muffler but so far no luck. RCS says the muffler that comes with the motor is very quite. Did you measure engine db's?

Thanks Dick, sounds like the perfect setup for me - just want small field practice airplane for IMAC on those days when the 40% is just to much hassle.
What header did you use to fit?

Roger

MOKI 1.8 header exact fit I used a MAC PRODUCTS and the stock noise level is way below any sport glow engines .
I have done a lot of DB tsting - and on this one -I did not bother -it is quiet. mellow no nasty piercing sound.
the little can that comes with it has a fine baffle - I redrilled mine to make all baffle holes max size - very littl differnce in noise and not much sound difference either .

Thanks for the info Dick.

I put a Zinger 17x6 on my roto25 and it is doing great. The midrange and top end with the 17x6 is great. With stock muffler spinning at around 7800rpms and unloading at little over 9000. unlimited vertical on my laser at 10lb.

ROTO 25 Prop (load) Chart

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Schpankme

What is the fuel consumption rate of the Roto25? How large a tank do I need for a 12-14minute run?

I am guessing that the fuel consumption is around 0.75 oz/minute?

Thanks,

Travis

I have 16oz tank it works fine for me. Not timed any flights. Gary

Any idea how long you're flying? How much fuel is left in the tank?

Travis

I will try to time it tomorrow and get a better Idea.

Gary

Sounds like about same results I got .

Any ideas on what size three-blade prop would be good for this engine?

Travis

ROTO 25 Prop (load) Chart - Three Blade

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Schpankme

Have one of those charts for the 35?

Please excuse my inexperience, but would someone please explain what the numbers mean in the prop chart? Also, how is it used to select a prop?

Thanks,

Travis

I timed 2 flights today first 8 1/2 min used about 1/2 tank 2nd flight 11min used just over 1/2 tank. This is with 16oz tank 17x6 prop fun fly style flying.

Gary

Thanks very much for the information. Your experience indicates a little over 1 minute per ounce of gas. I will plan on using a 12 ounce tank.

Travis

I would go with a 14 oz tank just to be safe.