Ultimate Dragmaster

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    Dohrman Crawford

    Hello, I am finishing up an Ultimate Dragmaster for the Classic event. I am at the stage where the instructions call for filling in the areas between the plywood ribs at the wing root area. It isn’t clear in the instructions if this means top and bottom of the airfoil or just the top portion. I am pegging away, planking the top and thought I would throw this out for a possible answer as I sure don’t want to add unecessary weight. However, if it will help or aid in keeping the wings on, I will do it. This is a nice looking airplane and I plan on having it flying by our late April contest. Maybe I will even know what I am doing with it by the time the Nats roll around.


    Hi dhrmc

    I hate to rain on your parade but fill-in usually means solid fill with block but if you fill in the top and bottom spaces between the ribs with 1/16″ sheet you achieve to same effect, just a little more fiddly to execute.

    We had a few Ultimate Dragmasters built here in OZ and like englishman John Coopers “Pink Elephant” design, required an extra top spar to stop the wing from breaking just outboard of the last ply rib, that’s where they all fail.



    Built Dragmaster about 30 years ago, and it never folded the wings, but they used to flutter if you pulled it hard off the line into good air.

    Sometimes the thing would flutter all the way down in less than a minute.

    l cured that by adding more diagonals in the wing, and re-covering it with double tissue on the centre panels.

    lt flew so good after that, that it flew away under D/T, very soon after ‘the fix’.

    Pink Elephant is still a popular model in OZ.

    Mine has in fact folded the wings, and so has had extra spruce spars in it now. Good low tech model, that go well.

    Dean McGinnes

    Hey Dohrm,

    How did your Dragmaster do last weekend?

    Dohrman Crawford

    It did pretty well, considering the wind. I flew it 3 or 4 times but it was really not a good day for trimming. I am going to move the cg forward from what the plan shows so it will be 55%. It will need a little more elevation in the stab t.e., but it should be more stable at a slight cost in duration. It tows very well, much easier to do than an A1. I was surprised to see how nicely it went up the line. I have a lot to learn, but am enjoying the process.
    We had some wind, Graham Selick put his Stratostreak across the ‘Hootch twice! Thank you Jim Walston!!

    Dick Bertrand

    A little late, but

    I filled in top and bottom with solid light balsa.
    You do a lot of grabbing the wings in that area and the extra weight is very little. Great glider!
    Dick Bertrand

    Dohrman Crawford

    I finally got some final trimming flights in on the Ultimate Dragmaster. I moved the cg a little bit, to get it up to 55%. One little shim under the l.e. of the stab and the thing flies like an eagle. Very pretty in the air. As to competitions, it is still an unknown quality, but the plane is probably much better than the guy towing it.

    Dean McGinnes


    Hows about some particulars. What structural mods did you do besides the sheet fill?

    Did you do the bottom of the wings as well as the top?

    What is yours covered with?


    Dick Bertrand

    Mine flew away with a stuck timer a few years ago.
    I still have two (now parts of two) built by deceased members of our club the “Guatemala Skyscrapers” (Rascacielos de Guatemala) You can tell I grew up in Brooklyn.
    We have a tradition. When a club member dies, we take one of his planes and try to lose it in a thermal. Wouldn’t you know it, we haven’t been able to lose either one of them (yet). It goes off with a statement on the wing telling the finder not to return it, but give it to a kid who can call us for lessons on how to fly it.
    Great and noble design the Dragmaster.
    Dick Bertrand

    Dohrman Crawford

    My Dragmaster weighs in at 13.40 oz. I am not sure if this is a good weight or a heavy plane. It flies like it is a reasonably light plane.
    Sandy Downs gave me the kit because he had a heart condition and knew he would never fly it. He had made some mods to the design. Since he reallly knows what he is doing, I made it according to his changes. The wing tips are pointed as is the vert. stab. The airfoil is also changed. I moved the cg to 55% and it immediately flew better than it did with the stock cg. It tows up like it is on rails and flies very well.
    I like it!!
    I covered the wings with polyspan, the roots are filled top and bottom with solid wood. Fiberglass cloth over that on the roots, and polyspan over that. Colored with Carnation Red Design Master spray paint. It is a looker. Fuselage covered with tissue/dope. Only thing I forgot is a place to put a Walston transmitter. I will use one of Hank’s bubble mounts.

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