Rotax 582 rpm problems

[cross_wind]

Not to hijack this post but I am having the same problem with my 582. I flew my Challenger II LSS on Saturday morning (first flight in Joburg) and could only get about 5700 rpm. My fuel burn averaged at 26 liters/hr and I wasn't getting more than a 200 ft/min climb (at cruise altitude). I do expect to have a slightly higher fuel burn as I have installed a BRS on the roof which is causing a lot of drag, but the guys in Canada are getting about 16 litres/hr on float equipped Challengers with 582's. The aircraft has a 3 blade Warp Drive prop but I am considering changing it for a wooden P-Prop.

So now the tweaking begins!!! Does anyone know where I can find the correct prop pitch settings? I looked on the Warp Drive website with no luck..

[Morph]

Simple,

pitch your prop so that your static RPM (the max rpm you get on the ground, with the tail of the plane tied to something immovable) is 6250-6400 maximum

That is it.

In flight you will then be able to get up to 6800 rpm

You should be able to cruise at 60mph, 4800rpm, 10l/h and 75mph, 5500 about 13-15l/h

[pierre]

Not to hijack this post but I am having the same problem with my 582. I flew my Challenger II LSS on Saturday morning (first flight in Joburg) and could only get about 5700 rpm. My fuel burn averaged at 26 liters/hr and I wasn't getting more than a 200 ft/min climb (at cruise altitude). I do expect to have a slightly higher fuel burn as I have installed a BRS on the roof which is causing a lot of drag, but the guys in Canada are getting about 16 litres/hr on float equipped Challengers with 582's. The aircraft has a 3 blade Warp Drive prop but I am considering changing it for a wooden P-Prop.

So now the tweaking begins!!! Does anyone know where I can find the correct prop pitch settings? I looked on the Warp Drive website with no luck..

Crosswind

Possible to PM your phone number for me.
Thanks
pierre

[cross_wind]

Thanks Morph,

I will give it a go this week.

Conrad

[Morph]

Do you have a prop protractor?

the pitch is too high, take it off say 2 deg to start and work from there

[cross_wind]

Yup I managed to get one from Cor @ Kroon (actually, he is helping me).

[cross_wind]

So I bought a prop protractor from Comet and headed out to the airfield on Saturday morning. We took out 3 degrees of pitch on the prop and torqued the bolts back in at 20 Nm. Then it was the question of do we tie the aircraft down and risk damaging something or try holding the brakes during ground run-up. I opted for the latter and lined up on the runway, held the brakes and opened the throttle. I must say that the new disc brakes on the LS Challenger are amazing and I could hold the aircraft stationary at 6000 rpm. At full throttle I was getting 6,500 rpm and blasting my way down the runway. I will test it this weekend to see what the dynamic rpm will be. I guess there is light at the end of the tunnel.

[Morph]

Once up in the air wack the throttle open and see that you don't easily run over 6800rpm. If you do, increase pitch by about .5 degree so that you are getting 6250 on static, before you start moving. I think you are going to be amazed at the difference in performance. You have now changed down from 3rd into ist

[cross_wind]

Yup, I could tell just by the sound of the engine at full. The 582 starts singing over 6,000 rpm..

[cross_wind]

Well I now think my rpm is too high. I looked at the Rotax manual and the max torque for a 582 (Mod 99) is achieved at 6,000 rpm. My Challenger's climb rate is terrible (100 ft/min) and my fuel burn is still too high. I am currently getting 6,600 rpm in the climb and will see what 6,000 rpm does for my performance. What I can't understand is how 5 Nm of torque can make such a difference ?

[Morph]

what is your cruise rpm?

[cross_wind]

No idea as I haven't really spent that much time in the air. Last Sat I was cruising at about 6,000 rpm and only got 65 mph - something doesn't make sense. I will test the cruise this weekend.