marwen1

My Feedback: (6)

Q) WHAT % OF NITRO SHOULD I USE with a ROSSI .81 cc engine?

This engine was last used in a DUCTED FAN system.

marwen1

MJD

My Feedback: (1)

What are you using it for now if not a ducted fan?

MJD

Aerobatx

My Feedback: (1)

at least 15% and if your wanting to get the most out of it 30%.

marwen1

My Feedback: (6)

MRD:

I installed it into a scratch build of LADDIE MIKULASKOS -"FORCE ONE" his BALSA USA version is 36.5" WS I bumped it up to 60" with detachable wing tips (pusher prop)



I have some 25% on han right now. ? Too hot?

marwen1

earlwb

Try your 25% fuel and see how it goes.
it should do fine.

AERORICH73

Ok, I just found the factory website for Rossi engines, and their R75F and R91F engines have a recommended nitro fuel content of 10%. These are engines for model aircraft. It would appear that a ducted fan engine would have a simliar oil content of the helicopter engines due to the high rpm's plus higher engine temps. A conversation with Dar Zeelon, and Cooper of Cooper Fuels would be helpful. Would not use the 25% nitro fuel you have until sure of what is recommended for your engine. I have a Rossi .40 from an E-bay win which I have run on 10% nitro, 20% all castor oil fuel. The stock muffler is a bit loud.

[email protected]

MJD

My Feedback: (1)

What sort of prop will it be loaded with? This is a fairly high timed engine and may be grumpy with too much prop.

MJD

marwen1

My Feedback: (6)

I have run some 5% in it about a year ago but only at an idle.. I am using a tuned pipe witha 14" TRI blade - PUSHER

marwen1

DarZeelon

Marwen,


It is a Rossi .81 cid engine; not .81 cc...
The multiplication factor is 16.38.

It is like driving a car with an mph speedometer in Europe and telling the traffic police person that just clocked you going 193 kph, that you were only going 120 on the speedometer...


This engine is a Rossi. This is a high-compression European engine and they recommend 0% nitro, particularly with the pipe.
If you have the extra head-shim in there, 5% is OK.


I do not know where the other repliers sourced their numbers...

marwen1

My Feedback: (6)

DarZeelon:

Like anything, you read inhale take a deep breath and evaluate EVERYTHING with a grain of salt!

Your response, makes ther most sense to me. Other than the fact that I'm not sure where my oil is comong from yet..

marwen1

DarZeelon

Marwen,


OOPS! I seem to have overlooked Rich's reply (post #6), which states the Rossi web site actually recommends 10% nitromethane for the Rossi ducted-fan engines.

Sorry, Rich.


As to oil; if you are not living in Europe and only have access to products of Klotz, Morgan and most other US producers of synthetic oil for glow engines, I would recommend using all-castor...

If you do have access to synthetic lubes from Cooper Fuels (ester based, US made), Fuchs, or from Motul, you can use them at 17% and add ~6% castor oil for heat protection, making a total of 23% oil, which is what the doctor ordered for ducted-fans.

Klotz (BĂ©NOL), Morgan (CleanCastor) and Sig (Baker's AA) are good, degummed castor oils.

MJD

My Feedback: (1)

Isn't asking a high timed ducted fan .81 to turn a 14" pusher prop a bit like hooking a plow to a Ferrari and blocking off half the radiator? Or will it be okay with this big load on the crankshaft?

MJD

jaka

Hi!
A 14" prop is too big prop!
Use a 10x10-11x8 APC.
Fuel: 20% oil or there about.
Nitro: 0-10% Max.
You notice when you run too much nitro that the engine gets very sensitive on the high speed needle and cut out abruptly.