Rotax 912ULS MAP and variable pitch

by Przemysław Wiśniewski in 912 / 914 Technical Questions 10 years ago

Hi. I just installed woodcomp sr2000 variable pitch propeller.
I trying to fly according to rotax manual MAP and RPM table.
It's ok but it not gives enough speed and/or economy. What can be effects of loading prop "a little bit more" than in manual?
It this mandatory to always keep MAP & RPM from the table?

Re: Rotax 912ULS MAP and variable pitch

by Kevin Machniak » 10 years ago

Kevin Machniak

6 167 40

I use the chart as a quideline .

I use the EGT readings as well to adjust the prop pitch .

There is a spot where the 4 egt's are even, thats where it makes me feel warm and fuzzy .

I can change egt readings with prop pitch and rpm , low pitch = higher egts on rear two cylinders , adding prop pitch brings the egt temp up on the front two cylinders.

I keep rpm around 5200. on my throttle that equates to about 1" travel to full , which gives room for a modest climb if prop pitch got stuck in that position .

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Re: Rotax 912ULS MAP and variable pitch

by Przemysław Wiśniewski » 10 years ago

Przemysław Wiśniewski

65 247 3

Hi Kevin. When you set pitch for EGT your RPM/MAP is near values from the table?

My questions are because my friend have the same plane (tl-96) and he usually sets big prop angle, rpm about 3800rpm and he have 210kph with 13lph.
I curious if it is safe, because it's very economic and fast.

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Re: Rotax 912ULS MAP and variable pitch

by Kevin Machniak » 10 years ago

Kevin Machniak

6 167 40

I just had a look at the table to refresh my memory of what Rotax recommends.

I fly at 5200 rpm , 26.7"HG MAP . As it works out this is where the EGT temps even out , HMMMM ? :)

So I would have to say yes I follow the table.

Your friend in my opinion is way overloading the engine and stressing components. How many hours on his engine doing this ?

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Re: Rotax 912ULS MAP and variable pitch

by Przemysław Wiśniewski » 10 years ago

Przemysław Wiśniewski

65 247 3

He bought plane a few month ago.. Second guy have new SR2000 prop and now he is looking good way to use it.
I'd like to find good, resonable way of using vrb. pitch prop.

It a little bit hard to influence on the psyche of person who spent a lot of money for magic sr2000 and now ha have to keep MAP/RPM instead fuel flow and airspeed :).

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Re: Rotax 912ULS MAP and variable pitch

by Alan Radford » 10 years ago

Alan Radford

0 15 1

Hi,
I have Woodcomp SR3000/3blade and I usually fly with 4800rpm and 24inch of Map whioh gives me on my Sportcruiser 105knots and 15-16litres/hr. If I want go quicker I use 5000rpm and 26 inches Map which gives 108/110 knots but pushes up the consumption to 18litres/hr.

As others have said 3800rpm is way to low!

Hope this helps.

Alan

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Rotax 912ULS MAP and variable pitch

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