Keil Kraft Gypsy Build Series - Pt 11: Braiding the Motor - 1949 Design by Bill Dean

Free flight Supplies- www.freeflight...

[@chuckdeyo291]

You have been very generous with with your not yet a revue. Any of us who have built much over the years have looked at that nice box art and dreamed of putting a model together, have been disappointed by what's in the box. But you are showing how to get over those issues. Thanks and keep up the good work.

[@MarkRobinson555]

Thank you very much, really appreciated 😀

[@roberttaylor2239]

Very informative,like your work shop,I'm 73 just coming back to modelling, did most variations of flying but not much rubber,currently finishing a guillows Aeronca champion 24 inch span. I have a gypsy kit waiting to be built in Greece so your video was very welcome. Thankyou and good luck with the motor winding

[@MarkRobinson555]

Thank you very much, really appreciate your kind comment, hope the Aeronca goes well 😀

[@davidpoll1042]

It might be worth noting that before it is wound the braided motor can be quite a bit longer than the distance between the rear peg and the nose block. However, once it has been wound up and allowed to run down in the model, the motor will automatically shorten and just sit nicely between the peg and the block - as if by magic. So you dont have to fiddle with the length of the braided (but unwound) motor before putting it in the model. I got that piece of information via a comment from Maxfiart.

[@MarkCroucherRC4fun]

All we need now is a "summer" 😊

[@EleanorPeterson]

The qualty of this kit really is disappointing. Very sad. The great thing about many old-school kits is that they were made by active aeromodellers or by knowledgeable enthusiasts who cared about the hobby - Chris Foss, David Boddington, Flair, Cambria, Keil-Kraft - and not by a company too busy counting beans to care about the product. You've shown admirable restraint in explaining the kit's deficiencies.😇👀 Meanwhile... Andrew Newton did an interesting experiment a few years ago. It was called "Free-spinning prop drag test", and featured a neat workshop demonstration of the difference in drag between a static versus freewheeling prop. He was trying to resolve the issue with regard to electric motors, and whether there was any advantage in using electric braking to stop an unpowered prop spinning in the airflow to improve gliding performance between bursts of powered flight. The results could be applied equally well to rubber-powered aircraft and would definitely have upset a lot of internet forum 'experts' who'd already made up their minds in the spinning v. static debate. They were the kind of people who refuse to believe evidence, facts, data and empirical proof, preferring instead to rely on hunches, blind faith and hearsay. In short, Andrew's experiment demonstrated clearly that a static prop generated less drag than a freewheeling one. Hmm... In a way it's understandable that people should find this wrong. It's counter-intuitive. Perhaps they imagine a stationary prop to be the equivalent of having a car with a flat rear tyre. Try to push the car and it'll be a lot easier if the wheel is free to turn, so common sense says that applying the handbrake would make the car harder to move. So... freewheeling a flat tyre along the ground is better than locking it with the handbrake and trying to push the car. Sounds reasonable. But an aircraft propeller is nothing like a car wheel. It's only in contact with air - which is a fluid and free to move, unlike the ground - so a more accurate analogy might be that it's like trying to push a car with a flat rear tyre which is lifted completely off the ground. It'd be like an old Citroën with its 'magic-carpet ride' hydropneumatic suspension. Such Citroëns could drive perfectly well on three wheels, with the 'lame' fourth one lifted clear of the ground where it created no drag with the road at all. Anyway, Andrew's experiment showed that the broad disc of a freewheeling prop created more drag than the narrow blades of a static one. In full-sized aviation, a static (not freewheeling) prop is normal if an engine stops. More sophisticated planes can 'feather' the blades, reducing their pitch to zero and minimising drag, but the blades are never left free to turn in the airflow if drag is a concern. A sailing yacht with an auxiliary motor has its propeller in the water all the time, so drag is a serious consideration. But the blades aren't left so that they can freewheel; they're locked and feathered to zero pitch just like an aircraft's propeller, which produces least drag. Variable pitch propellers aren't a practicable option for most model aircraft, so I suppose the best thing drag-wise would be to use a folding prop, which avoids the freewheeling v. static argument altogether. I used to build rubber-powered free-flight duration models with folding props. I think some full-sized gliders with motors have folding propellers too, but I don't know of any which have a freewheeling option. As Andrew's experiment showed, if a prop can't be folded, it's better to lock it than to have it turning in the wind. I welcome all comments and criticism from armchair experts for the ideas expressed here, but do please watch Andrew's video first before shooting me down in flames...🙂

[@MarkRobinson555]

Thank you very much for the comment and interesting information, which sounds very reasonable, certainly food for thought 😀

[@johnroberts3723]

Very interesting, I've been following the build with nostalgic enthusiasm as I built this model as a teenager back in about 1977 from the original kk kit. My building was probably quite rough back then being blinded by the excitement of it all and I think from memory they referred to braiding as pretention and quarter flat rubber wasn't supplied in kits but was sold by the yard off of a roll in model shops and it wasn't anywhere near the quality of the rubber available today probably 250 winds was maximum if you didn't want to risk smashing the fuselage beyond repair.

[@MarkRobinson555]

Thanks for the comment, pleased you enjoyed it

[@scottobrien3484]

Great video Mark. I’ve wondered how these braided motors are made. It’s also nice to see people going through a learning process too. Can’t wait to see this flying!

[@MarkRobinson555]

Glad you enjoyed it, thanks for the comment 😀

[@adamchess4543]

I wonder if silicon would be okay to lubricate a rubber motor with? I think it will fly just fine with that prop, probably the only usable thing from that kit.

[@MarkRobinson555]

Thanks, appreciate the comment. Not sure about the silicon, hopefully someone will answer that 😀

[@collinmccallum]

we love your videos! much respect and keep up the great work.

[@MarkRobinson555]

Thank you so much, really appreciate the kind comment 😀

[@rubberfly]

Very well done 😁

[@MarkRobinson555]

Thank you! 😁

[@ronaldrose6885]

Nose bearing ..well done Mark.

[@MarkRobinson555]

Thanks 👍

[@roydavies2442]

I always though you 'pretensioned' the rubber motor ?.

[@terryblackman6217]

A very enjoyable video and interesting video today. It definitely needs a bigger prop. Why not try and carve your own it's really not that difficult. I haven't looked but there must be many videos out showing how to do it. I also cannot believe how bad this kit is, especially if you are a newbie to the hobby.

[@MarkRobinson555]

Yes, totally agree, will definitely fit a bigger one, first I am interested to see how poorly it performs with the one from the kit 😜. Carving a prop should be great fun. Pleased you enjoyed the video, thanks for the comment 😀