Rotax 582 RPM drop during climb

[dalords]

We flew our kitfox for the first time last week, it was the first time ever flying an experimental with a Rotax 582. I noticed that any change in pitch has a big change in RPM during a climb. Is this common? I can lose almost 500-800 RPM in a 200 foot per minute climb. That is with only one person in the cockpit. Almost afraid to try it with 2 people if it is that sensitive to pitch change. What is normal for a 582?

[Av8r_Sed]

OK, whichever prop you're running should be pitched to give a static full throttle RPM OF 6200 to 6300. If my memory serves, you're shooting for around 6500 RPM in climb for the best climb performance.

On my grey head 582 with two blade 70" Ivo medium I'm seeing 6200 RPM for a climb rate of about 600 fpm at 60 mph indicated. This is a compromise that allows a bit higher cruise od about 80 - 85 mph.

What prop are you running and what static RPM do you see?

[dalords]

Running a IVO prop, 3 blade I believe its the ultra light prop not the medium on a rotax B gearbox. On takeoff roll 5700 RPM is all it would make.climb out it dropped down to 4700. Upon level off it went back to 5700, but any change in pitch up it would drop to 4700. I have no idea where the pitch is set at. Contacted IVO today and got the instruction on how to reset to neutral. Was just unsure if that type of rpm drop in climb is normal

[Av8r3400]

What tachometer do you have? Needle (analog) tachs are notoriously inaccurate on these. Could be 1000 rpm or more off...

[Av8r_Sed]

That kind of drop isn't normal and if your reported RPMs are accurate, you're not getting anywhere near the full rated power out of your engine.

I installed a Tiny Tach and ditched my analog gauge. It was a small investment and it provides good numbers.

The Ultralight IVO should be a good match if you're close to a 68 to 70" diameter.

I would be hesitant to fly it until you can get reliable static RPM above 6000.

[dalords]

using a Rotax Tachometer. The manufactures says accurate to within 25 RPM. set the prop back to neutral and static run still only made 5000 RPM. not sure what to think

[Av8r3400]

Either your engine has serious issues or that tach is junk (I'd go with the latter).

Just because it says Rotax on it doesn't make it perfect...

Get a tiny tach.

http://www.tinytach.com/tinytach.php

Amazon (http://www.amazon.com/s/?ie=UTF8&keywords=tiny+tach&tag=googhydr-20&index=aps&hvadid=41808909809&hvpos=1t1&hvexid=&hvnetw=g&hvrand=17228997890535351009&hvpone=&hvptwo=&hvqmt=e&hvdev=t&ref=pd_sl_1jrgglvnzb_e)

[FoxDB]

When I got my KF1 w/ 582-C & IVO-3 UL. I had the same problem as you describe. I re-pitched the prop to 6400 in climb and it was a different airplane. Then after years of flying with the Westach Tach, I got a tiny tach and found my westach was indicating 400 RPM too high. I verifed the Tiny Tach with an RC Tach and it is correct. Re-Pitched the prop again and performance is improved again. Long story short get a Tiny Tach and re-pitch.
Dave

[dalords]

FoxDB we are in Idaho Falls. what is your climb rate during this time of the year? I understand that the tach is not 100% accurate but I still think I am not making full power. That would explain the fact that I can only make about a 200 Foot per minute climb on a July evening around 8:00 PM. When you re-pitched the prop where you more pitch or less pitch from neutral?

[Dave F]

You should see 700 to 900 fpm climb on that Kitfox

GET A TINY TACH !!!!

you need to know what your RPM is
Rotax tach - throw it away