Re: When the fusestick becomes a bottleneck...

From: Sameer Tiwari <deevana_2001_at_yahoo.com>
Date: Thu, 11 Jun 2009 19:53:07 -0000

Hi,

Thanks LeRoy and Benjamin for the replies...

After some more experiments over the last two days, I realized that even though the MS bows, its the prop holder which is bending way more.
I am using the Ikara gray plastic prop assembly.

I do the back off everytime to get the corrrect torque on my home made torque meter, but the plane still dives :-(

The length of MS from prop to hook is 7 inches
Rubber is Tan 2, 1/32 - about 16" long, brass ring attaches the rubber to prop.
MS is 1/4" X 1/2" grain running lengthwise.

Maybe I should make the MS with two sticks and pass the rubber in between?

Thanks,
Sameer


--- In Indoor_Construction_at_yahoogroups.com, Benjamin Saks <bensaks@...> wrote:
>
> It would help to have some key information:
>
> Length of your motorstick from the prop hanger to the rear hook
> The cross sectional area of rubber that you are flying on
> The grain orientation of the balsa wood that you have built the motorstick
> from
> The cross sectional dimensions of the motor stick
>
> Keep the following in mind:
>
> The motor stick will bow when loaded with a fully wound motor. You should
> expect this to happen and use it to your advantage.
> You can build in some slight upthrust to counter-act the down thrust from
> the bowing motorstick.
> You can also use balsa to make a tension bracing for the top of the MS.
> Balsa is strong in tension and does not stretch.
>
> With more information I think we can help you out.
>
>
>
> On Mon, Jun 8, 2009 at 12:25 PM, Sameer Tiwari <deevana_2001_at_...>wrote:
>
> >
> >
> > Hi folks,
> >
> > Having built several of the indoor models over the last year. I kept
> > bumping into the issues of a the plane taking a nose dive, whenever I put
> > turns in the rubber exceeding a 1000.
> >
> > I am sure the folks on this forum know what I am talking about...
> >
> > The fusestick warps/buckles under the stress and causes an unwanted
> > upthrust from the prop, causing the plane to nose dive. Once you pick it up
> > and let it run a few seconds, it will fly beautifully once again giving
> > close to 2 mins of flight time.
> >
> > But, I want to stretch more to exceed 3mins, and stuck on the fusestick
> > design, it has to be balsa - no boron/fiber/tubes etc.
> >
> > BTW, I did try a box design with two 1/32 X 1/2 for a pair of sides and
> > 1/16 X 1/16 for the other, and it was equally weak as a solid 1/4 X 1/2.
> >
> > Any ideas?
> > Thanks
> >
> >
> >
>
>
>
> --
> BEN SAKS
> Project Designer
> bsaks_at_...
>
> WET
> 10817 Sherman Way
> Sun Valley, CA 91352
> T 818.769.6200
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>
Received on Thu Jun 11 2009 - 12:53:11 CEST