Transisto

Guys, it's only a gimmicky display. It's 4 m up in the air so there is no oportunity to interact with it this year. I've also got to make a 60 cm diameter rotating Earth globe with geostationary satellite out at 2 m; a 150 mm moon to be positioned at relative scale about 18 m away; stands on refraction of light; polarisation (why do fishermen wear sunglasses but pilots don't), colour perception and the human eye; physics of sound with tubular bells, electric guitar, sine, square and triangle-wave generation and display on oscilloscope; and several other things. If I can get the planes to fly in a circle for two hours at a time in the morning and afternoon then it's a win! Thanks for all the interest and suggestions. @Robin Colbourne gave me the correct terminology and a practical setup reference which saved me a lot of development time. For me, "pretty good" will be good enough.

@Trevor, thanks, but there are two problems with that. 1. I won't have time! 2. The speed is determined by the central motor. The planes are unpowered.

Thanks, @Robin Colbourne. The simpler approach is much more sensible for this application. I cut a P-84 out of 4.5 mm "Foamex" equivelant (foam board clad with light plastic film). It caught fire on the second pass of the laser so I extinguished that and finished the cut by hand. I got enough informaton from the linked article to balance it up well enough to fly on my motorised whip arm. I've some further work to do but I'm off to a great start. One question for now: the wings now have square leading and trailing edges. The leading edges are straight so I could glue on a drinking straw to reduce drag. Thoughts? I'll report back over the weekend.

I wonder if I fastened the control wires to my swing arm in a vertical fashion could I get it to self-regulate? If the plane goes down the bottom wire would go slack and the top wire would turn the elevators up. As the plane comes up the top wire would go slack ...

Thanks, @Robin. Your understanding is correct and "whip-controlled" may be the search term I'm looking for. A quick search has shown up Whip-power P-84. Am I on the right track? This one seems to have elevator control so that stunts can be performed. How would I trim this for fairly level flight?

Hi, Simon. Yes I had found that on my research but I'm trying to keep it simple and use stuff that might inspire young engineers of the future. I'm an electrical engineer so that part of it wouldn't scare me but would add expense that the kids might not be able to afford. So far the only specialty item is the motor-gearbox and they're readily available from a breaker's yard. Is there any reason what I'm proposing is a non-flyer?

I'm helping run a STEM (science, technology, engineering and maths) expo for school children in both primary and secondary schools in my neighbourhood. We have plenty of tabletop displays but the hotel balloom has a very high ceiling and it seems such a shame to waste all that space. 😉 I have some window winder motor gearbox units that run at 30 RPM and I thought it would be nice to mount these on top of poles and have some simple models swinging around - see the simple sketch. I have the system working just using a washer on the end of a string and it has potential. Could someone post a sketch of a simple aircraft - preferrably made of flat card or similar. I have a laser cutter so I can do complex 2D designs but that also means that I could do inner structures for the wings and put a good profile on it. I'd accept any tips on where to attach the string and adding a little weight if required. What would be a good "string" to use to minimise wrapping around the pole or general tanglement? Many thanks.