Angled Instruments

[facthunter]

Without "don't use RPM's" It's still not critical to have the exact RPM set. you should have limit pitch stops for fine for take off.. I've just read the whole 3 pages and missed the prop info.. . Is it CS.? Your MP is pretty much height dependent (for the full throttle position at least) and you can't over boost it unless you have a blower.. You would have to be a bit insensitive to overpitch it... Nev

 

 

[BirdDog]

The prop does not have predefined stops. It’s electric with a button on the dash with lights to show full fine or full course.

 

To set the prop in the cruise I need to be able to see RPM and MP properly. Would be nice to have them right under my nose.

 

 

[facthunter]

It must have limit stops. Usually they are variable to accommodate the stall speeds of different planes. and an overspeed situation as well. It may require dismantling to do it.. or be set at the factory to cover the anticipated range you might expect in service. That might be a little rough to be optimum if it's the case.. Nev

 

 

[BirdDog]

It has end stops. But nothing in between.

 

So you have full fine at one end and full course at the other. In between there is no predefined stops. Just a button that adjusts it between full fine and full course.

 

So in cruse the pilot has to adjust the pitch to get the best RPM/pitch combo to get the best out of the flight. The two gauges needed for this are MP and more importantly RPM. With them on the right side and flat, it’s a PITA!!

 

 

[facthunter]

OK so is it CS or just in flight variable pitch.. When you leave it alone (don't move the adjustment) and vary the airspeed does the RPM change? Your MP won't vary much . Just fall as you climb with gain of altitude and if you close the throttle..Nev

 

 

[BirdDog]

Just in fight adjustable - not constant speed. I have to adjust pitch and throttle to get the best RPM for cruise etc.

 

 

[facthunter]

Well if that's the case, it's not going to be very steady. You will be chasing it all the time. Do you have an autopilot? Nev

 

 

[BirdDog]

No AutoPilot either.

 

 

[facthunter]

Well my advice would be to let it wander over an acceptable range. It will vary with a bit with airspeed as any fixed pitch prop does. You can fix it into a lot of positions. The good thing about CS is you can set and forget. Move the throttle, climb and dive. As it's not good to chase airspeed. (you tend to overshoot/undershoot) so it will be with the pitch you strive for. Nev

 

 

[BirdDog]

Thanks Nev,

 

I just need to make sure I am not loading the motor up with RPM that is too low, and I think it's why Evektor moved the RMP and MP to the pilot side when they fit an adjustable prop!

 

 

[facthunter]

Once you get a bit of altitude, the chance of doing that rapidly reduces. It's identical in principle to having a variable ratio gear box. in a car.. You could in theory make it slug by excessive coarse pitch at near full throttle at low level and run too few revs. Your prop pitch is like a wing, where there is an optimum slip angle equating to the wings most efficient angle of attack to the relative airflow. Your forward (True airspeed) alters the pitch you want for the RPM you choose. It's all bit complex deciding slip. Most of this is done from maker prepared/approved charts so you can plan more accurately. The 912 is a pretty forgiving engine. You are unlikely to detonate it but there will be a sweet spot somewhere. You know the max recommended RPM ..Keep a few hundred below that to try a high speed cruise and it will run there all day. Try different rpms and see what performance you get Economy and True airspeed . I think unless you are flying near the ground say at above 3,000, Full throttle ( Position) won't be a problem unless you do silly low revs. as you climb you get less and less horsepower because of MP drop. Nev

 

 

[BirdDog]

Thanks Nev,

 

Yep! The advise from Rotax is to run at about 5200 RPM. Just back from WOT and the prop coursed up to achieve that in the cruise. So going to play with that and see what I can see.

 

 

[BirdDog]

Hey Nev,

 

Bit of an update for you mate. Managed to play yesterday and I had to back off at 115, as it was too lumpy! LOL! I still had more throttle and pitch to go, so it really can boogie!

 

That said, it will take some getting use to trying to spot the RPM from the other side of the dash. Pain the backside! I have a request in with RAA to see if I can get it relocated. But happy with how she went yesterday.

 

Cheers

 

John

 

 

[skippydiesel]

.........................SO... does anyone have any ideas on how I can rectify this? Maybe retrofit some sort of angled bezels etc?I am open to ideas.

 

Cheers

 

J

I used different length vibration isolators (the ones that have a threaded rod at each end) to tilt the whole right panel in my direction.

 

Works a treat.

 

Very cost effective & easy compared with trying to angle each gauge separately.

 

I should also point out that I redesigned my panel at the same time, as when you angel, you effectively "shorten" in terms of mounting hole location & esthetic fit.

 

 

[BirdDog]

Thanks Skippy.

 

My dash is all one piece - sadly. My buddy did the same with his. Angled the half that he needed to. Works a treat.

 

 

[skippydiesel]

Hey Nev,...............................trying to spot the RPM from the other side of the dash. Cheers

 

John

I can't understand the logic of having the tacho on your right side - along with fuel & manifold pressure, it's as important as your flight gauges (no revs. no fly).

 

 

[BirdDog]

Yep! My point exactly. The later models actually have the RPM on the left, AND, it's double the size! So somewhere along the way they decided it's a bit more important!

 

My plan is to get it on the left side - come hell or high water. It was a real PITA yesterday trying to set that prop for cruise, and having to lean over to see it. With a PAX, it would be worse!

 

 

[Downunder]

Would it be easier just to add an extra rpm gauge on the left?

 

A bit wierd doubling up, but you only have to worry about an installation rather than a relocation.

 

Even if it was something of a semi permanent set up....

 

 

[BirdDog]

Yep! That is possible too!

 

I have written to RAA asking - but as yet, not heard back. This time of year, it's understandable.

 

 

[skippydiesel]

Yep! That is possible too!I have written to RAA asking - but as yet, not heard back. This time of year, it's understandable.

Almost certainly RAA will refer you to the manufacturer for a decision -

 

So I suggest you try and contact the manufacturer ASAP - If , as you say, later models of this aircraft have the RPM on the left, I shouldn't think they will have any issues with you relocating or adding (as per DownUnder's advice).

 

Just make sure you get their agreement/approval in writing to wave at RAA .

 

 

[Yenn]

If you want a tachometer on the left, how about putting in a “Tiny tach” it takes up very little room and can be be very accurate. It only needs a wire wrapped around a plug lead to operate.

 

 

[facthunter]

Won't your row of lights act as a position indicator for the prop blade angle?. After you are used to it just set to the position you prove works and set the throttle to an MP. After you climb a bit it will be wot, most likely as your MP will gradually fall with height gain. You shouldn't have to be constantly changing pitch(revs). Nev

 

 

[Bruce Tuncks]

What strikes me about this thread is the ease with which we have given away our property rights. Who does the darn plane belong to anyway?

 

Imagine this applied to your household... you may be denied the use of your bathroom unless the bath manufacturer agreed to your cleaning schedule.

 

I say do what you want and don't tell.

 

 

[BirdDog]

@NEV - My prop adjustment does not have a row of lights. Just a BLUE for full course, and a YELLOW for full fine. There is no indication in between.

 

@Bruce Tuncks - I am with you on this. Ok... if I was making a modification the bird that was major, and would change either how it flies, or how one flies it, I could understand. The manuals speaks of the RPM gauge, but it does not speak of where that gauge exists on the dash. If my LAME is able to completely remove the engine and replace it, without much fuss, why in gods name he can't move the RPM to the left is beyond me.

 

Anyways... I have an LOA on the way from Evektor, so my problems will soon be over. :)

[turboplanner]

What strikes me about this thread is the ease with which we have given away our property rights. Who does the darn plane belong to anyway?Imagine this applied to your household... you may be denied the use of your bathroom unless the bath manufacturer agreed to your cleaning schedule.

I say do what you want and don't tell.

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