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Building Tips and technical articles. => Building techniques => Topic started by: Denis Downs on May 22, 2007, 06:46:10 AM

Title: Prop Nut/Nose Weight
Post by: Denis Downs on May 22, 2007, 06:46:10 AM: I have a tail heavy stunt plane and am looking for a 'acorn type' prop nut that is made of brass or other heavy material that I can install on my OS-FP40. Have looked at the normal supplier's web-sites but have not found one. Does anyone still offer these in various weights to fit a 1/4-28 thread?

Thanks,

Denis Downs
Title: Re: Prop Nut/Nose Weight
Post by: Bootlegger on May 22, 2007, 06:50:21 AM: Don't know if Harry Higley is still in business or not, but I think he used to make them... H^^
Title: Re: Prop Nut/Nose Weight
Post by: Alan Hahn on May 22, 2007, 06:52:42 AM: http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXL729&P=SM
Title: Re: Prop Nut/Nose Weight
Post by: Bill Little on May 22, 2007, 09:27:31 AM: Remember that these place a lot of "bad" weight on the end of our crankshafts and help speed up the wearing out process of plain bearing/bushing engines. Especially Fox 35s! According to what I have been told, it might be the best cause of broken cranks in the fox35. Adding lead to the airframs nose is safer for engine life.
Title: Re: Prop Nut/Nose Weight
Post by: Mark Scarborough on May 22, 2007, 09:52:32 AM: I seem to remember hearing about melting lead into the cub on the backplate as an option,, not sure if I would melt it into there or form it and then attach it,, but hey its an empty hole,, might be a good place to hide it also
Title: Re: Prop Nut/Nose Weight
Post by: Bill Little on May 22, 2007, 10:22:31 AM: Quote from: Mark Scarborough on May 22, 2007, 09:52:32 AM
I seem to remember hearing about melting lead into the cub on the backplate as an option,, not sure if I would melt it into there or form it and then attach it,, but hey its an empty hole,, might be a good place to hide it also

I have seen quite a few "stuffed" backplates! LOL!! Actually, if the backplate is bolted in position, I have not see ill effects from just pouring the melted lead straight into it. As a safety measure I have also seen a plate made to keep the lead in place being held with the back plate screws.
Title: Re: Prop Nut/Nose Weight
Post by: Roger Vizioli on May 22, 2007, 11:45:17 AM: Quote from: Bill Little on May 22, 2007, 09:27:31 AM
Remember that these place a lot of "bad" weight on the end of our crankshafts and help speed up the wearing out process of plain bearing/bushing engines. Especially Fox 35s! According to what I have been told, it might be the best cause of broken cranks in the fox35. Adding lead to the airframs nose is safer for engine life.
What Bill said.
We have a two piece Fox crank in the club to prove it! HB~>
Roger
Title: Re: Prop Nut/Nose Weight
Post by: Jim Thomerson on May 22, 2007, 01:25:16 PM: I've run heavy hubs for years on various glow engines with no problem. (Do not recommend them for diesels, however.) On the other hand, I've broken various glow engines (and diesels) which have never seen a heavy hub. So, you pays your money and you takes your chances. I have filled a backplate with steel BB's and made a plate to cover it and hold them in. No problem with that.
Title: Re: Prop Nut/Nose Weight
Post by: Alan Hahn on May 22, 2007, 05:59:07 PM: I have made the calculation and shown somewhere (SSW I think) that the moment of inertia of a heavy hub is neglible compared to a modern plastic prop. I haven't cut up a wood to calculate the difference. Remember what counts a lot is that the flywheel effect depends only linearly with mass (or weight) but on the square of the radius to the mass.

I am sure nothing is tougher on the old Fox than a plastic 9-6 Foxberg/FoxyHazel prop!
Title: Re: Prop Nut/Nose Weight
Post by: Marvin Denny on May 22, 2007, 07:43:30 PM: Dennis, I have a used one--- $5.00 and I will pay shipping.

If interested E-Mail me at <mdenny4@cox.net>

Bigiron It is just like the one pictured above.