Duo-Mono (oz7945)


Duo-Mono (oz7945) by S Cal Smith 1950 - plan thumbnail

About this Plan

Duo-Mono. Control line semi-scale model of the Delanne Sport Model 20.

Quote: "Is it a tailless bipe or a mono with a misplaced empennage? The Delanne builds easy, performs like a dream.

Experiments in various wing arrangements with full-scale aircraft have resulted in some pretty strange shapes through the years of aviation development. Successful results have been frequent; yet fallen along the wayside we find combinations such as the canard, tandem wing and circular wings. Today designers have pretty well settled for the conventional wing stabilizer or all wing set-up.

The original versions of Maurice Delanne's double-mono-plane were singularly successful. They possessed a high degree of maneuverability, a high top speed, together with a very low landing speed. Air Trails has been fortunate in securing from Mr. Delanne drawings of his Sport Model 20 which was built and flown in France during 1938-1939.

The design lends itself admirably to sport control line flying, and although not a strictly scale version of the large Delanne 20, we hope the design liberties taken will not offend.

The 31 inch span model weighs in at 24 ounces. Considering both wings as effective area (according to Mr. Delanne) gives a total of 280 sq in wing area. Wing loading is 8.5 oz per 100 sq in. If only the front wing is considered effective area (184 sq wing loading comes to 13 oz per 100 sq in. The model has good stability in flight, but we would rather assume the loading to be higher than the 8.5 oz figure. If you split the difference, loading is probably closer to 10-11 oz per 100; at least that's the way the model feels out on the end of the wires. So don't attempt the full stunt pattern with this ship although you can have plenty of fun with big loops, horizontal eights and inverted flight. The K&B 29 in the nose furnishes plenty of power - speed is a little above 70 mph.

Construction follows standard practices and a strong light structure has been achieved without excess weight. The fuselage can be built first. Cut out the two 1/8 sheet sides. These should be of medium hard or hard stock..."

Direct submission to Outerzone.

Quote: "Steve, I came across a great line control plane from the October 1950 Air Trails magazine, the Duo-Mono. I have no way to clean this plan up or put it into CAD [ed: fixed - is now scaled and cleaned]. From a cursory internet search, this type of aircraft has almost been mostly forgotten. I see someone submitted a more basic model than this. Hopefully the readers will appreciate this little known gem. Marc"

Supplementary file notes

Article pages, text and pics.


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Duo-Mono (oz7945) by S Cal Smith 1950 - model pic

  • (oz7945)
    by S Cal Smith
    from Air Trails
    October 1950 
    31in span
    Scale IC C/L LowWing
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 31/07/2016
    Filesize: 593KB
    Format: • PDFbitmap
    Credit*: MarcHenshaw
    Downloads: 1139

  • Delanne_20-T | help
    see Wikipedia | search Outerzone
    Test link:
    search RCLibrary 3views (opens in new window)

    ScaleType: This (oz7945) is a scale plan. Where possible we link scale plans to Wikipedia, using a text string called ScaleType.

    If we got this right, you now have a couple of direct links (above) to 1. see the Wikipedia page, and 2. search Oz for more plans of this type. If we didn't, then see below.

    ScaleType is formed from the last part of the Wikipedia page address, which here is https://en.wikipedia.org/wiki/Delanne_20-T
    Wikipedia page addresses may well change over time.
    For more obscure types, there currently will be no Wiki page found. We tag these cases as ScaleType = NotFound. These will change over time.
    Corrections? Use the correction form to tell us the new/better ScaleType link we should be using. Thanks.

Duo-Mono (oz7945) by S Cal Smith 1950 - pic 003.jpg
Duo-Mono (oz7945) by S Cal Smith 1950 - pic 004.jpg
Duo-Mono (oz7945) by S Cal Smith 1950 - pic 005.jpg
Duo-Mono (oz7945) by S Cal Smith 1950 - pic 006.jpg
Duo-Mono (oz7945) by S Cal Smith 1950 - pic 007.jpg

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User comments

I enclose photos of a model Delanne 20T-02 tandem aircraft, which may be of interest [pics 004-007]. This is a 1/5th scale RC model based on various 3views and photos, I built this in 2011 and it is still around and flies beautifully on a 2stroke 46 glow engine. The c of g is set at 54% of smg.
Most 3views show the undercart too far forward and on this model I moved it back 2"!! Also it should be noted that the original Delanne 02 was built by SAFRA and not Arsenal as quoted in most texts. The colour of the 20T-01 was red and built by Arsenal, whereas the colour of the 20T-02 was blue and built by SAFRA. Cheers,
Bill Coles - 12/10/2023
Hi Bill
Care to share the R/C version plans here on Outerzone please?
Sybrand - 19/10/2023
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* 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.


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