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Obviously too much time on my hands

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I have been fooling around with AutoCAD a bit lately so I thought I'd preview a 'thoughie' I have been having.




At the moment the firewall is moved 39" rear for the rear motor (for CG reasons), the front firewall is at the canard. The canard has been extended by 12" both sides (to allow a more forward CG), at the inboard ends. There is no elevator here.


It has twin Jabiru 3300s. 120HP. With these and the extensions I wouldn't imagine this would add much more than about 200# to the Cozy.


This is all purely fiction, no intention of really doing the maths and actually building the thing.

Adrian Smart

Cozy IV #1453

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Cool... a lighter defiant. That would be a project to complete, but doable. Is the nose gear different?


Regarding the elevators, you might want to keep them close to the fuselage and leave the outermost ends of the canard without the elevators. I'm not sure though. Where do you want to disrupt the airflow? Around the fuse and the aft engine, or outboard around the wings. Not sure how much this matters either way.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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Is the nose gear different?

The nose gear shown is fixed. The empty CG should be forward enough of the main gear, hence the canard span increase. This would be a small weight saving up front I think. I am trying to get every extra bit of weight off the nose and right out the a$$ (hence the rear motor moved so far back).


You make a good point about the elevators. After I drew this I thought about it and wondered how the torque tube could carry through to the elevators this way. Perhaps I'd have original middle section and elevators with a 12" extension on each end, no elevator.

Adrian Smart

Cozy IV #1453

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Looks luverly, but would 120 HP be enuf to get off to continue climbing if you have an engine failure on take off? If not you only have the option of closing the throttle on the good engine if one fails. Adding to that, with double the number of engines compared to a Cozy you have doubled the chances of an engine failure.


The Jabiru engines are lighter than Lycosaurs, even the 5100. Try two of them? Be nice if they made a 5 cylinder version with 150 HP :D

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09

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I think 120HP would still give some, maybe marginal, climb ability at low levels.


Think of an O-320 with 160HP. At 8000' you'd be getting max about 75% = 120HP. Anyone know a Cozy with a 160HP motor that can't climb past 8000'.


High density altitudes might be a problem, but that doesn't effect us much here in Aus.


Add fuel injection and electronic ignition to the the Jabby and you might end up with 135HP or so.


I think it is do able. I will probably not go any further with the design. This all came about with me doodling in AutoCAD.


Anyone wanna create a model in X-Plane to try the theory ????

Adrian Smart

Cozy IV #1453

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  • 5 months later...

There was a Long-Ez derivative called the Gemini that was written

up in the old Homebuilt Aircraft magazine on Dec. 82.


Long-Ez wings with cs and fues 18" wider.

Two 2000 cc type IV VW engines 188 lbs ea. 65 hp at 3100 rpm.

Fixed mains with retractable nose.

Fues 41" wide at seats.

Canard used airfoil same as Rutan AMS/OIL biplane racer.


Wingspan = 27.6'

Wing Area = 123 sq ft

Canard span est. = 16 ft

Canard chord est. = 2.25 ft

Empty Wt. = 1150 lbs

Gross Wt. = 1850 lbs

Top Speed TAS = 185 mph

Cruise 65% = 160 mph

Stall speed = 70 mph

Takeoff speed 70 mph

Single engine climb front only = 150 fpm

Single engine climb front only = 200 fpm


I think it was later retrofitted with O-200 engines

and possibly a different canard.



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  • 2 weeks later...
  • 2 months later...

I too must have too much time on my hands because I'm seriously considering this concept using two corvair powerplants.


I actualy flew with Dave Ganzer, the original designer/builder (with Burt's input), in his Gemini way back when.


So far I have scaled 3-views of the Gemini, Defiant, Cozy IV, Baird's 2EZ and Velocity to the same scale to compare component placement. I also have Defiant plans and downloaded AeroCanard plans for reference. In addition I've studied Martin Holomans Aircraft Design and Composit Design books as well as several others.


It seems a very viable concept not to mention just plane cool (no pun etc., etc.). Why not just build a Defiant you ask. Well I just don't need a 3000lb. 360hp fuel guzzler to carry 2 plus baggage.


BTW, I have seen a few pictures of some dude in France that was almost done with a 3/4 Defiant (Baby Defiant?) using Rotax 912's.


I am really stoked with this idea. Of course I am also majorly fired up with the idea of building a composite copy of the Siai Marchetti SF-260. Talk about diverse ideas!


I'm in the middle of a job change and major relocation to composite building friendly, very dry west Texas. I hope to make a start on SOMETHING in the next six months (finally!).


Raiki, feel free to contact me if you want to discuss this further. This could be the start of a really cool couple of projects :-)



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The Defiant is actualy much closer to a tandem wing aircraft than a true canard design. Holomans book does address some of the ramifications of tandem wings.


Also very interesting is that the Defiant canard tapers in % thickness while maintaining a constant chord (not counting the tapered chord canard tips). My guess is that Burt very cleverly did this to tailor the lift distribusion of the Defiant canard. Pretty sharp guy, surprise, surprise!



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  • 4 months later...

Been a while since lurking here but hi again.




What about two 2.5 ltr Subaru auto engines. More than adequate power.


Al Wicks Cozy IV originally flew on one of these engines. That way single engine power is at least a certanty. Maybe even smaller Subie engine.


Just thoughts.



"An upsidedown Australian that wants to build an aircraft that flys backwards"

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  • 6 months later...

I LOVE the Gemini in concept, I really wanted to build one. I watched and waited for plans. In the end though, I decided to build a dragonfly. The speed, cockpit size, and handling characteristics are about the same - actually the single engine Dragonfly is a little better in most of these areas, although cargo space is not as functional - but with half the fuel consumption. I think for an airframe of this size the weight and complexity of the extra engine gives no real pay off in terms of performance or economy, which is I suspect why it never went into production. I still want one though... if for the safety if nothing else, not to mention the coolness factor.

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