Re: F1D rubber and o-rings

From: Fred Tellier <fred-tellier_at_cogeco.ca>
Date: Mon, 17 Sep 2007 13:05:07 -0400

Tapio

Your 9+ inch motor will work well when your model looses some weight, I use motors around that length except for low ceilings when I go up to 1" shorter. As for torque I always release at full torque both on the F1M and F1D. The F1M torque is double F1D torque 1 to 1.2 in oz compared to .45 to .55 on the F1D. The stick will take the torque but watch the motor length as it is shorter than the motor stick hook to hook length, a spacer might be needed to ease the strain on the model. I use 1/8" OD thin wall high pressure pneumatic tubing for O rings and even they will occasionally twist on the prop hook. but their size doesn't cause a great problem when I leave them that way for the flight. If it looks like they are too twisted I will hold the motor close to the hook and let the prop spin allowing the twisted O ring to straighten out. This is a scary thing to do with a torque up motor so I usually fly with them twisted.

Fred
  ----- Original Message -----
  From: Tapio Linkosalo
  To: Indoor_Construction_at_yahoogroups.com
  Sent: Monday, September 17, 2007 1:12 AM
  Subject: Re: [Indoor_Construction] F1D rubber and o-rings



  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-


   

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Received on Mon Sep 17 2007 - 10:14:33 CEST