XTS-912 Performance

[eastmeg2]

I've noticed there are a few of you out there with XTS-912's.

 

I collected mine from Airborne last week and flew it for the first time this weekend. (Not the first time I've flown one).

 

Airborne claimed they set the propellor pitch so that the 912 can rev to 5500rpm in flight. However I find that mine will only rev to 4900rpm.

 

Could it be that the engine is new and tight and will free up with time?

 

I suspect the prop pitch is set too coarse and will bring this query up with Airborne this week, and would appreciate any feedback from you more experienced XTS-912 owners & pilots out there.

 

It still cruises 56 knots (GPS) burning only 9 litres/hr 2 up. - amazing after 6 years flying Edge X Streaks at 48knots at 15 litres/hr.

 

And yes, we had definitely removed the airfilter covers.

 

Cheers,

 

Glen

 

 

[Guest Crezzi]

I very much doubt that your engine is tight so prop pitch is a possible explanation. IF you are going to adjust it note that the POH recommends using less than full power for take off at light weights.

 

Cheers

 

John

 

 

[eastmeg2]

Thanks John,

 

I take it that you did not experience the same thing when you took delivery of your XT.

 

I've been operating at less than full power anyway, especially early in the takeoff roll since we have a grass/dirt strip and no stone gaurd net yet, although the GRS chute does help provide some protection. Hence it was only when I was established in cruise 3500ft AMSL and specifically tested climb performance that I noticed the engine would not rev above 4900rpm. Our airfield is 2500ft AMSL.

 

Cheers,

 

Glen

 

 

[eastmeg2]

I've just heard today from a friend who is collecting their XTS-912 from Airborne today that aparrently Bert Floods has installed the wrong gearbox ratio on a batch of 912 engines they sent to Airborne. Both our trikes were built at the same time, being completed on Friday 13th, of all days. . .

 

I think we'll be having some words with Airborne on Thursday morning to see what they're going to do to fix it.

 

NOT IMPRESSED !!!

 

Glen

 

 

[Guest Crezzi]

I didn't even know there were different gearbox ratio options on the 912 ! If yours is fitted with the wrong one it seems odd that Airborne didn't detect when they test flew the plane.

 

John

 

 

[JayKay]

I own an XT-912 which I bought new from Airborne in Feb. 2005. It has the same problem. I can't get the engine revs much above 5000 rpm. I spoke with Airborne at the time and they told me that I probably set the pitch of the propeller incorrectly. I checked it together with my Airborne dealer and found it to be correct.

 

I am glad you guys have found this as I will also be having a chat to Airborne on Monday! This may have been going on for some time. I wonder how many other XT-912s are affected.

 

Also not impressed!!

 

John

 

 

[eastmeg2]

Airborne have now installed the correct ratio 2.43 in my gearbox and it nows revs to 5400rpm in a static engine test on the ground. Hopefully this will translate to optimum peak engine revs in flight of 5500-5800rpm. Weather is looking promising for this weekend, so I hope I'll have some good experiences to report next week.

 

 

[eastmeg2]

Have managed to get in a couple of hours flying yesterday afternoon.

 

The 912 is now revving to 5400rpm in a climb and performing noticeably better than before. Thanks to Airborne for doing the right thing.

 

It's still likely that I will be trying to achieve the correct propellor pitch as it looks like one or more blades may still be pitched a bit coarser than they should be, but won't know for sure until I can implement an accurate method of measuring the pitch on each blade, following instructions provided by Bolly at Natfly.

 

Cheers,

 

Glen

 

 

[eastmeg2]

Measured the pitch angle on all 3 prop blades yesterday, although with the wing on the trike we could not get the trike onto a proper flat surface. This introduces a constant error which is unknown, but highly repeatable.

 

What we were able to determine is that the pitch on the 3 blades is the same to within 0.1 degrees, and that the actual pitch angle is approximately the recommended 20 degrees.