Re: F1D rubber and o-rings

From: Tapio Linkosalo <tapio.linkosalo_at_helsinki.fi>
Date: Mon, 17 Sep 2007 08:12:38 +0300 (EEST)

On Sun, 16 Sep 2007, Akihiro Danjo wrote:

> It seems that your rubber is too thin, because your model is about 28%
> overweight. If your prop is normal size, I think that the loop length should
> be about 200mm or so. No need to worry about the excessive torque. Only need
> a few 10 turns back-off.
...
> I think your 4mm tube must be also OK. Isn't the rear hook too short?

Thanks, Aki. I'll try a shorter motor. I think this should help, as -
unlike my model last autumn - this one showed a positive climb so I think
I'm close now. Last years model just climbed for a few seconds on the
burst, then stalled and lost all altitude.

Re the rear hook, I think I found the reason. I had to cancel my last
flight on Saturday as I noticed that the hook had worked loose on the
bottom. The top held ok, so I suspect that the motor jumping off was
because the hook bent forward, and thus the twisted to release the rubber.
Luckily it is easy to fix, as I have the rear wing pylon just behind the
hook - a short lenght of kevlar thread to anchor the hook to the pylon
should do the trick.

From: Fred Tellier <fred-tellier_at_cogeco.ca>
> Probably a 8 inch loop would be better, I think 240 mm if almost 9", I
> think you may not be winding to enough torque. How high are you
> climbing?

240mm / 25.4 (mm/in) = 9.6in. So I need to try a shorter motor. What kind
of torque compared to F1M do F1D motors and motor tubes stand? The model
climbed maybe about 8 meters (25 feet), but I backed off some as I did not
dare to load a motor with full torque to the model.



-Tapio-
Received on Sun Sep 16 2007 - 22:48:07 CEST