Engine Revolutions

[Blue Max]

The wing of my Aquilla 582 is at the most forward nodge for best speed..I notice that the engine revolutions is almost always more than 5000 rpm when carrying a passenger and perhaps a lyttle less when flying without a passenger.
The other day I was at Jenna,s workshop and for a while we had the engine running at 6000 rev,s on the ground..It sounds frightening to listen to the noise and Jenna made the remark that the engine is not made to continouisly work at those revolutions..
I am getting worried because 5000 or 5300 is not that mutch less and surely that cant be a good thing to fly for two hours at those revolutions.????
When the wing was adjusted to fly slower it took less revolutions to keep the aircraft at equilibriam.
Another question..Is 6000 Revs on the ground holding the aerie vas and 6000 revs in the air (Flying) the same thing.???
Can somebody please put my mind at ease about these things..Many thanks.

[Chris Liebenberg]

Blue Max

The Rotax engine manual states MAX RPM = 6800

The manual also gives fuel burn figures at 75% power continiously, which calculates to 5100 RPM

Operating at 5300 RPM is only 77% of power.

My Windlass with Rotax 503 DCDI operates at exactly the same RPM, 5000~5300 with pax, and 4800 solo.

After 460 hours, it still purrs like a kitten.

Give it revs, the Rotax likes it!

Regards

Chris

[Trikenut]

I don't know all the technical aspects of engines (I'm not an mechanic!). But the manual for the Rotax 503, as Chris said, states 6800RPM max.

On the Aquilla I train on, (Aquilla 1 with 503 and Aquilla 1 Wing) we fly straight and level at 5000 to 5300RPM dual. I'm not sure of the RPM on take-off though.

From what I understand: the position of your hangpoint affects your flight characteristics in 2 main areas. Furthest back position: High lift, lower speed. Middle position: Middle of the range lift and speed. Foward postion: Higher speeds, lower lift. It then stands to reason that if one moved the hangpoint backward or forward, you would need less/more RPM to maintain level flight.

Hope this all helps,
Trikenut (Ross)

[Big-D]

Blue Max - Your revs perfectly normal, in fact actually quite good and just proves again that Aquila wing is very efficient

Most of the 582's I have flown need 5500rpm straight and level 2-up.

I flew a Airborne 582 that required 5900 rpm one up straight an level - That was a little high - Wing more suited to 912 engine

The comment about 6800 max rpm is correct - Don't run it there for too long - not neccesary with Aquilla anyhow as it climbs like a bat out of hell even at 6200rpm

D

[Morph]

You can run a 582 at 6500rpm all day if you wanted to as long at the water temps are within spec. (6800rpm max 5 min)

It is better to run the aircraft in the 5000 to 5500 range than below, where the engine could be labouring and flying lean. If you have EGT gauges, watch them at different rpms and you will find hot spots in the lower rev regions. You want to find the coolest spot as your cruise rpm.

[Paul_Meanwell]

Hi there Blue Max,
My Aerotrike Cobra (582) has the hang point in the middle but has similar RPM. 4900 solo and 5100-5200 with pax. Max revs are 6450.

Cheers!

[Arnulf]

Blue Max

The Rotax engine manual states MAX RPM = 6800

The manual also gives fuel burn figures at 75% power continiously, which calculates to 5100 RPM

Operating at 5300 RPM is only 77% of power.

My Windlass with Rotax 503 DCDI operates at exactly the same RPM, 5000~5300 with pax, and 4800 solo.

After 460 hours, it still purrs like a kitten.

Give it revs, the Rotax likes it!

Regards

Chris

A little correction here. 75% power does not equate to 75% RPM. Power consists of RPM and torque. If you have a very fine pitch, you can have 6800 RPM, but will not have full power. Furthermore, if you look at the power graphs in the manual, you will see that the power the motor produces is not linear with the RPM. Also note that according to the graph, max performance is at about 6400 RPM, and not 6800 RPM.

Regards,
Arnulf

[Blue Max]

Thanks everybody..I feel more confident that everything is in place..and I fly with less worries..Thanks again..