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Sterling Cirrus for Aerotow?

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  • Sterling Cirrus for Aerotow?

    Someone tell me I'm nuts before I run off and start building another bespoke creation.

    A friend of mine gave me an old Sterling Cirrus kit. Most of you would already know this, but if you are not familiar, it's a die cut kit from the 60's which is all built up balsa with an 87" span. The original kit was meant to be a towline glider, or single channel RC. Not sure many people got these things to fly very well mainly because of their somewhat fragile construction, large airframe but light weight contributing to the fragility, and lack of small RC equipment back when these things were popular. Link added to one that is partially built if you are not familiar.

    My reasoning for building one of these probably started when I was about 8 years old and dreamed one day of building everything in the Sterling catalogue. Maybe I'm living with 8 year old rose colored glasses on, maybe not, but I've got to believe that by leveraging micro- RC equipment and more modern materials and build techniques that one of these airframes could fly pretty well. And that got me thinking that the best configuration may be to build it either with a motor in the nose or in aero tow configuration. Given the size and lightweight nature of one of these, I thought aero tow made a lot of sense. And then considering this thing could probably be towed up with a 1/6 scale electric Piper Cub or something similar, it becomes even more interesting.

    Thoughts? Good idea or should I just build it and hang it from the ceiling?
    Back in the early to mid 1970s, I began construction on one of these Sterling Cirrus sailplanes.

  • #2
    If you are set on making it a flying rc model, I'd stick to the lightest micro gear you can find and put a motor in the nose with a small folding prop. Research your covering material. The freeflight world is chock full of info for the best strength to wait ratios for everything from 1g competition indoor planes to the most demanding high strength fabrics for top level high performance outdoor planes.

    Aerotowing without beefing up everything, or reengineering the whole kit would not end well in my opinion. Keep the speeds really low if you tow it.

    The most fun I could have with it would be to a) have access to a grass covered gentle slope soaring site, and b) build it as a pure glider with minimal rc channels, then fly it on super light days when everyone else is waiting for the wind to come up.


    • #3
      Dion, I built and flew this model FF back in the 70's when I was living in England. We would glide it down a gentle slope and retrieve and repeat endlessly!
      I think you will find it is to fragile to aerotow as the wing structure twists very easily, if I remember correctly. It finally was captured by a tree and as you can imagine, trying to retrieve it we destroyed it I suggest you build it and hang it up for display.
      Just my 2 Cents!



      • #4
        Thanks for the input guys, much appreciated. I was thinking about this yesterday some more, and the need to re-engineer this kit to make it work is probably an understatement. I started thinking about all of the wood that would need to be replaced, the carbon that would need to be ordered, and the chance that is still flies like crap. Maybe hanging from the ceiling in my office is the better idea.



        • #5
          Maybe, scan/copy the parts to build a bigger one!


          • Dion Dunn
            Dion Dunn commented
            Editing a comment
            I thought about that, but it really is engineered to be not much more than a free flight model. If I were to scale it up, I’d build a fiberglass mold for the fuselage and probably cut foam cores for the wings. Then it would end up being the ultimate ‘re-engineering’. It took me 2 years to finish the Sparmann, it would take me to retirement to finish a scaled up Cirrus.