Prop wire?

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Need for Speed
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Prop wire?

Post by Need for Speed » Fri Oct 14, 2005 9:31 pm

I have seen two ways to bend the prop. wire.

Some bend a 90 with 1/4'' leg.

Others say to bend it in a U over the hub.

Can any one help???

Thanks!!!


Thanks !!!

mdmoe
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Re: Prop wire?

Post by mdmoe » Fri Dec 16, 2005 10:45 am

From some trials, it appears you have to bend it in the 'U' so it hooks over the prop. When I had it bent at 90 degrees, when I wound it to about 50 turns with 3 rubberbands, the wire slipped. The only problem I can see with the 'U' bend is the prop can't free spin after the band unwinds, but in a Space Derby that shouldn't be a problem.

Michael Moe
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clemsontigerfanatic
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Re: Prop wire?

Post by clemsontigerfanatic » Thu Dec 29, 2005 6:18 am

I came across a good link with some photos on prop wire assembly

http://www.etekgadget.com/SpaceDerbySpa ... uction.htm

I'm sorry if its a commercial link but the link is free



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Colibri
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Re: Prop wire?

Post by Colibri » Wed Apr 26, 2006 2:11 am

I do rubber-powered free flight as one of my hobbies. The prop hook that is supplied with the kit, in my opinion should be folded over. The reason the hook would be bent to 90 degrees is that while flying a free flight airplane you want the hook at a 90-degree angle so the prop would free wheel. If you look at the prop shaft you will notice a ramp, which is there to allow the prop to disengage after the tension in the motor has decreased. If the prop doesn’t free wheel it would cause drag and bring the airplane down sooner. In the case of the space derby the race wouldn’t be that long and the need for a free wheeling prop isn’t there. If you want to have a freewheeling prop carve the ramp so that the height of the ramp is one and half times the thickness of the prop shaft. This would prevent the prop shaft from slipping over the ramp. Better yet ditch the prop, which has no camber, and purchase a prop from a hobby store that is designed to produce some lift, or any lift. The best solution would be to throw away all of the front end and the rubber supplied in the kit and start over with parts that are designed for the application of producing thrust by rubber powered.



John Shreffler
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Re: Prop wire?

Post by John Shreffler » Sat Sep 22, 2007 8:55 am

I bought the Space Derby kit from BSA, and put it all together, getting everything "right" using every bit of advice I can find on the web. Still, I can't get it to fly more than 5 feet down the line. I was looking at the propeller, and it does not seem to have the curve that would really move air. Indeed, the breeze it produces seems very weak for the diameter and RPM. The previous poster's comments regarding the propeller are the only ones that I have found that support my own observations. I suppose that one of the rules is that you must use the BSA official propeller, but I am going to visit a hobby shop and see what else is out there.

My interest is to work out the details for interfacing an electronic finish line to this race format. This part is simple. Getting the spaceship to move is my problem.


John Shreffler
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John Shreffler
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Re: Prop wire?

Post by John Shreffler » Mon Oct 01, 2007 7:50 am

Update on my shakey start at making a spaceship: Originally, my design was like a baseball bat, heavy in the front. When I simply attached the carrier, the ship was seriously nose-heavy. This put a lot of friction on the forward loop, putting the brakes on. Also, my ship was generally pretty heavy. So, I got out the carving tools, and did some serious weight reduction, especially in the front, ending up with very slight nose-up balance. It flies like a champ now. You can see my improvement at http://www.newdirections.ws/images/Space.JPG I also learned the advantages of using multiple rubberbands, more power with less stress on each band.

Thanks to many who emailed me good advice, and got me headed in the right direction.


John Shreffler
Maker of The Judge

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