incidence/CG problem with Timeless Flyer - RC Groups
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Mar 08, 2004, 05:26 PM
Jim in Santee
jshelton's Avatar

incidence/CG problem with Timeless Flyer


Just flew my new Timeless Flyer. This is the old-timer style 480-powered plane from Hobby People. It has the wing mounted on a pylon like the old Playboy freeflight models.

On the first flight, I had to hold almost full up trim to keep the plane from diving (power off). I moved the CG back to the rearmost point suggested in the instructions but the same problem persisted as well as making the plane a lot more twitchy. I then decided to increase the wing incidence by 1/16: and it flew slower with less up trim needed to maintain a shallow glide path. However, it is still much too fast for an undercambered old-timer model so I increased wing incidence to 1/8". I flew it several times with this setting and it seemed to fly much slower and have a much better glide. However, I still have to fly with full up trim to keep the plane from speeding up/descending too quickly.

It appears that I need to raise the wing incidence even more so that I don't have to use full up trim. However, it's hard to believe that since the fuselage has the wing and stab mounts molded in that the default incidence could be so far off. I considered moving the CG back but I'm already at 34%.

Any ideas what the problem might be???
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Mar 09, 2004, 01:25 PM
Hiigaran member
Lone Yankee's Avatar
My first though would be to address the prop downthrust setting, but if you are having this issue power-off then that rather dismisses that theory. If you can, try some weight reduction from the nose, heavy landing gear components are infamous for being heavier than needed.

Good luck -LY
Mar 09, 2004, 05:44 PM
Jim in Santee
jshelton's Avatar
thanks for the feedback. The problem is during power-off flight. I will probably try moving the CG back and see if it helps.
Mar 09, 2004, 05:46 PM
Nickel what?
Phreakish's Avatar
duh question: Whats your weight? and what's the wing area?

an undercambered wing should make lots of lift and have not trouble keeping the plane in the air - but they do have some funny pitching moment quirks.

Whats your elevator incidence relative to the wing?
Mar 09, 2004, 05:55 PM
Jim in Santee
jshelton's Avatar
The plane weighs 22 oz.

Wing Span: 61 in.

Area: 370 sq. in.

Don't have an incidence meter but the stab looks like it has about 2-3 degrees negative incidence in relation to the wing.
Mar 09, 2004, 06:00 PM
Nickel what?
Phreakish's Avatar
hmmmm... thats odd then.
Dec 16, 2004, 07:57 PM
Parrothead Extraordinaire
Mark Gund's Avatar
Mine flew great, out of the box. No pitch change, any or no throttle setting.
Nov 14, 2012, 08:20 PM
Registered User
pval3's Avatar
any updates on your results?
building one now . . . any thoughts in retrospect?
thanks
Nov 16, 2012, 03:01 AM
Jim in Santee
jshelton's Avatar
Quote:
Originally Posted by pval3
any updates on your results?
building one now . . . any thoughts in retrospect?
thanks
Haven't flown it in years. Might just have been an isolated issue since other people don't seem to have had a problem. Good luck - it's a nice plane!
Last edited by jshelton; Nov 16, 2012 at 03:57 AM.