Dragonfly builder in Ontario

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eltonhodges

New Member
Joined
Jun 6, 2021
Messages
3
Hello All,

Just started a prebuilt fuselage and wing project and am looking to begin hot wiring my canard. I'm going to be putting in my 912 Rotax for the motive power part. Any input on what would be the best way forward for prop? I'm thinking a Powerfin 52 inch 3 blade, but does anyone see an issue with a three blade on the Dragonfly. I know the 2 blade is more efficient, but I don't see a two blade handling the power in such a small diameter, or at least not very efficiently.

Thanks for any and all input.
 

dwalker

Well-Known Member
Joined
Mar 6, 2021
Messages
146
I am actually at about the same state with my Dragonfly and will be posting some of the wiring/plumbing stuff I do to mine on video and likely in posts here. My Dragonfly is on tricycle gear at the moment and I am finishing out the interior panels as it moves forward into wiring and plumbing work.

I am using the Corvair motor with EFI, which *should* make 110-120hp (but likely closer to 130hp) so my wiring will be slightly different, but probably not too different than what you will be doing. I am also using dual toe brakes instead of the parking brake, and a few other updates.

I am still working out what to do about a prop. I have followed Mark Langford's KR2 very closely and he has done a lot of prop testing, so using his information as a base and going from there. A ground adjustable prop has also been recommended.

Will help anyway I can

Cheers!
 

eltonhodges

New Member
Joined
Jun 6, 2021
Messages
3
Hi D,

Thanks for the reply. I was thinking of tricycle as well, but I'm flying off of a grass strip, so decided to play it safe and go with MKII gear. I'm going to do the bent aluminum route for the main (a la Grove type). I don't like the inboard canard gear or hoop, it just seems like a lot of work for little gain. If I was on asphalt runway, tricycle would the cat's meow.
Corvair is a nice powerplant, seems to have a lot of followers, decent power for weight too. I'm only using the Rotax because it's what I have available from another project. It has the Edge Performance big bore kit and EFI, so just hits 100hp. Little bit heavier than Corvair and the liquid cooling means the added headache of radiator install, but will be nice in winter, which we have a lot of up here in Ontario. Are you going to put in reflexed ailerons, or just keep it simple and straight aileron?
 

dwalker

Well-Known Member
Joined
Mar 6, 2021
Messages
146
Hi D,

Thanks for the reply. I was thinking of tricycle as well, but I'm flying off of a grass strip, so decided to play it safe and go with MKII gear. I'm going to do the bent aluminum route for the main (a la Grove type). I don't like the inboard canard gear or hoop, it just seems like a lot of work for little gain. If I was on asphalt runway, tricycle would the cat's meow.
I am actually setting my plane up for both tailwheel and tricycle configurations. The setup currently on the plane is very tall, has decent sized tire/wheel combo and is probably going to work fine off most soft fields, but taildraggers are cool. I am making my own glass hoop from the newsletter.

Corvair is a nice powerplant, seems to have a lot of followers, decent power for weight too. I'm only using the Rotax because it's what I have available from another project. It has the Edge Performance big bore kit and EFI, so just hits 100hp. Little bit heavier than Corvair and the liquid cooling means the added headache of radiator install, but will be nice in winter, which we have a lot of up here in Ontario. Are you going to put in reflexed ailerons, or just keep it simple and straight aileron?
I would pay a lot of attention to the amount of weight you put in the nose. The airframe was designed for a small VW motor, and like anything else, we just keep hanging bigger and bigger engines off of it. The Corvair is about as heavy as I would want on the front, and I was strongly considering sticking with the VW in a 2135cc size. Rolling through the newsletters, I do remember that a 1.8 turbo Subaru was very popular for a while, along with an attempt at the Mazda rotary, so maybe it will be fine. I picked the Corvair because there is a Corvair expert within an hour of me, his son has a Corvair flight motor in a plane, and its a mechanically dead simple motor.
I will be using EFI and coil-per-plug to run the engine, so not really the typical Corvair install.

My plane has had the reflexors started, so I am installing them. I am actually at this point trying to decide whether to use a servo for electronic control or use the eccentric as shown in the newsletters. At this point, it would be pretty easy to do the electronic setup and use a linear or string pot for position wired to the ECU and displayed on the engine monitor.

It gets almost cold here in TN, so I have already laid out an engine oil heat exchanger as part of the cabin heat system. I am fundamentally pretty opposed to heat muffs on the exhaust, as the idea of potential carbon monoxide poisoning seems no fun.

Cheers!
 

eltonhodges

New Member
Joined
Jun 6, 2021
Messages
3
Yeah, the move has been to bigger motors from the original VW. I do know that there are now a few 912's on Dragonflys, but they've all required a bit thicker firewall with some additional strength added by 2-3 plys of carbon along the firewall to exterior fuselage as well as interior wall. Basically creating a strong plug at the firewall/fuselage/landing gear interface. Still lighter by 50lbs than the O-200 that some are using on the Q200 and DFly :) .....
 
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