performance vs wingtip length?

[13brv3]

Greetings,

OK, so the Onex has been out quite a while now. Has anyone tried both wingtip lengths and recorded the difference in climb and cruise for each? I seem to recall something about the shorter tip not meeting the stall requirement for sport pilots, but I'm not concerned about that. The only downside I can see with the shorter tip is reduced climb, but I'll be running a 912UL (80HP) with a less than ideal length prop for climb, but I still have to believe it will out climb the average Aerovee.

I would probably have opted for the short tips from the beginning, but the project I bought has long tips. My plan was to fly it like this first, then try the shorter tip. Unfortunately, I noticed today that one of the tips is REALLY warped at the rear inboard edge, and it would definitely create some unwanted roll. Since I have to rework them, I'd plan to go to screws and maybe go to the short tips. I figure I can always go to the longer ones later if I feel I need more climb. We have a 6500 ft runway, so climb rate won't be an issue during the initial test flying.

Thanks,
Rusty

[gcm52]

If you haven’t purchased your engine yet I would suggest you consider the 100 hp 912ULS, my opinion is this increases the fun factor for the Onex by 100x and you will never worry about climb.

[13brv3]

The plane is almost ready for inspection. I actually had the 912UL already on another plane that I hated, so I bought the Onex project as a better host for the engine. I guess I do everything backwards. Most people buy an engine for their plane, but I buy a plane for my engine :-)

To stay interested in any project, I have to leave room for improvements, and adding power will certainly be something I'll consider in the future. I do like being able to run 87 octane, and I wanted to use the stock landing gear to keep the folded height as low as possible. That limits prop length to the bare min for the 80 HP engine, so adding power may require a number of other changes. Again, that's a problem for the future. If an Aerovee flies the plane, then the 912UL won't have any problems.

Cheers,
Rusty

[petep]

Where are people finding a Onex engine mount for a Rotax 912. I have a flying Onex that I built with a AerVee but am interested in a possible HP upgrade.>

thanks,
Pete

[13brv3]

I don't know of any engine mount for the Onex 912 combo right now. They're all custom made.
Rusty

[13brv3]

I cut the wingtips to the optional shorter length. I was surprised to find that 7.5" on each tip adds up to about 6 lbs. I hadn't even considered that as a benefit.
Rusty