Duo-Flex (oz8065)


Duo-Flex (oz8065) by Harley Michaelis 1969 - plan thumbnail

About this Plan

Duo-Flex. Radio control sailplane model.

Quote: "Both a superb slope and thermal soaring machine, the Duoflex was designed without resort to limiting compromises. Fully aerobatic, this glider features interchangeable wingtips and optional power pod.

The Duo-Flex is a graceful and efficient soaring machine, functionally designed sturdily built. Without resort to limiting compromises, it is both a superb slope and thermal soarer. It utilizes interchangeable wingtips secured by a foolproof plug-in system. At once, you have a 99 in wing for thermals, or sloping in winds from 12 to 25 knots. Or, with the short tips, you have a 79 in wing for greater speed and penetration.

Separate hatches, one for the purist and one for powered flight, add further versatility for variable weather conditions and mode of flying. Small car? Worry not. The main wing section fits into a VW Bug!

While the ship will handle satisfactorily on rudder-only when properly trimmed out, its full potential is best realized with true proportional control of rudder and elevator. It then becomes quite acrobatic and will loop with power, deadstick and on the slope. It will turn tightly, in spite of a seemingly small rudder. On the slope you have a free ride until the lift is gone or your batteries are tired. With a hot .09 you are quickly in thermal country and the Duo-Flex can be kept in an optimum turn by transmitter trim alone, permitting relaxed, sus-tained flight until it is time to come home.

With a slow sink rate and high glide ratio, landing approaches are long and fiat. A little up just before touchdown and it will flare for long distances and grease in, light as a feather.

For you more experienced soarers, try a Duo-Flex for a new taste! You other guys, who don't even know what we mean, start soaring, for a new world of R/C pleasure!

Construction. Use Tite-Bond glue except where epoxy is specified. Select your balsa with care. The wing must be built last. Form the two wing saddle blocks from hardwood, such as birch or maple. The rear block is narrower since it will be planked over. Cut the slots for formers 'L and T in the blocks on a table saw and bevel on a joiner or work down with a wood rasp. File a groove For the rubber bands in the contoured outside edges, about 1/4 in deep.

The beveled ends of the wing center section are also grooved and the wing is neatly secured by just 3 or 4 rubber bands (red rubber newsboy bands are ideal) tightly doubled over the beveled ex-tensions of the wing..."

Supplementary file notes

Article pages text and pics.


Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction

Duo-Flex (oz8065) by Harley Michaelis 1969 - model pic


Do you have a photo you'd like to submit for this page? Then email admin@outerzone.co.uk

User comments

No comments yet for this plan. Got something to say about this one?
Add a comment



Download File(s):


* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.


This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.


Terms of Use

© Outerzone, 2011-2024.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.