BMW engine on a Dominator

[Viper22]

Would there be any problem using a BMW R1100S engine (98hp) with a MSA gear reduction on a single or two place dominator? There seems to be a lot of people in Europe using this engine with great success. Just would like to hear from the readers and contributors. Thanks :)

[gyroblackwell]

I have not seen one yet. I did see a honda virgo (750cc) on a WWI biplane home-built, and it flew great. He used 2nd gear for take off, and then shifted to 3rd when he had leveled off.

You would need to mount the motor so that the prop shaft was close to Center Line Thrust. The clutch (if it is a shaft drive) comes in real handy for starting and warm-up without the prop spinning!

I will check into BMW mountings, and shaft drive sys.

Tim

[GyroRon]

tim when they Convert a Bmw engine to use for flying purposes they remove the clutch and gearbox leaving only the engine itself.

[barnstorm2]

I can't say anything for it's use in a gyro but I love my R1100S. Great performance.

[scottessex]

Do It! Do It! Do It! Do It! Do It! Do It! Do It!

I would love to do the same thing!

[gyroblackwell]

Ron,

too bad! cause it is really wild when the prop stop on the runway, yet the engine is still running strong !!!! HA!

talk about a jaw dropping to the floor!

tim

[scottessex]

Remember, the propeller is not there to provide thrust, it is there to cool the pilot.
Just watch how much he sweats when it stops turning!!

[quadrirotor]

a little bit heavy but very good! :)

[quadrirotor]

for reference:

http://aircopter.chez.tiscali.fr/photofr.htm

:)

[James Hawkes]

http://twistairclub.narod.ru/maks2003/images/smaermecchi013.JPG

This page shows a machine v similar to ernie boyette's dominator which uses the bmw - I believe the manufacturer used to import the dominator, tho I may be wrong on this point - hence the similarity?
see Take Off Ultraleight Flug in Germany for neat aero conversion of the BMW 1100S engine.

[jos]

From all the machines I have seen there is one common thing: very little power for a two seater.
Altough they claim 100+ hp the performances are a lot lower compared to the 912s Rotax.
I have two clients who used the 100hp in fixed wing ultra lights and they finally removed the engine after a lot of hasle with different exhausts, engine computers, intake systems etc etc.
It has been used in the Spanish Futura and it was removed after one day testing.
I posted a question on 3 different forums to find out if there is still a two seater gyro flying with this engine and never found one still in action!


JOS

[MikeBoyette]

Jos,
If it has similar power to weight ratio as the 912 then it should work fine. I would only be concerned about keeping the engine cool. A gyro has so much stuff in front of the engine that a free air engine doesn't fare well. Give my Dad a call he should be able to tell you one way or the other.

[jos]

Indeed IF the power to weight ratio is identical.
I strongly doubt the power. Does a 1130 cubic cm two cilinder put out the same power as a 1388 cubic cm 4 cilinder?
The volumetric efficientie of a very fast running (7500 rpm) is difficult to bring to 100% and this 100% is required for 100hp. It is also more difficult to reach this in a 2 cilinder, that is why it needs 4 valves per cilinder.
The above gyro's in the pictures such as aircopter have very sloppy performances, today this people do not fly them anymore, but use a 912s or 914 turbo.
I know 5 two seater gyro's with all the same problem, no power.
One of my clients has a coyote fixed wing and changed the rotax 582 to a 80 hp BMW.
The performance was worse with the BMW.
The germans convinced him to change the engine to the 100 hp model.
He did but could not find the 20 hp.
I also saw the russian take off video with the dominator and BMW engine.
During take off roll the front wheel dropped 3 times on the ground and the machine needs 14 seconds for lift off at 7 degrees C below zero.
A magni M16 with a 912s engine takes off in 8 seconds at 20 degreesC.
Assuming the speed is around 60 kmh or 16 m/s the difference in lenght is around 100 meter not to forget the temp difference of 27 degrees.
I posted on 3 different forums a question regarding this engine on a semi enclosed two seater but found no answer.
The germans made publicity with the Spanish futura gyro and their engine on their website.
Now the Futura only flew ones with this engine and severely overheated.
I asked them for an explanation and they replied to me who else was also building a two seater with their 100 hp engine.
They could not give me any reference of somebody flying this engine succesfull.
Tommorow I'll contact a freind in Italy who made his first flight solo with his two seater.
2 weeks ago he told me on the phone he only flew 2 circuits because there was very little power.
The germans advised him to change the computer!!!
I myself made some years ago a BMW conversion. After 3 different propellers different exhaust pipes modified intake system etc, we installed the prop from this engine on a test bench.
There was 31 pecent power short!!!!
As far as I am concerned those people sell air for the same money as a 912s.


JOS