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Old Jan 21, 2012, 03:18 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Second Flights

Norm et al,

Beautiful morning!

I removed the ballast from the right wing. It still has a little roll to the right.

Do not have all the data yet, but it looks like 8 Amp cruise at 60 kmh is likely. Max speed was 100 kmh and stall is 25 kmh. 50 to 60 kmh cruise is comfortable.

Norm's NM57 is excellent for this application.

Will probably try some auto flights tomorrow.

Tom
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Last edited by Tom Harper; Jan 21, 2012 at 03:29 PM.
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Old Jan 21, 2012, 03:20 PM
agnotology
kcaldwel's Avatar
Joined Jan 2007
3,650 Posts
Nice!

I like to see something besides the same old planforms out there flying.

Kevin
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Old Jan 21, 2012, 03:35 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Kevin,

Thanks

It leaves the ground at about 1/3 throttle. So, I think we will be able to hand launch - after developing some confidence.

Tom
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Old Jan 22, 2012, 07:44 AM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
The wind is howling this morning, so flights are unlikely.

Tom
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Old Jan 22, 2012, 03:33 PM
internet gadfly
nmasters's Avatar
Colorado
Joined Aug 2006
2,186 Posts
Glad it's turned out well so far and I hope this plane makes a good photo platform. Concerning the heavy wing issue: Nobody likes non functional ballast so maybe you could increase the area of the heavy wing. Either by increasing the chord of the aileron or the wing span by gluing a tip extension on. Of course it would increases the spar bending moment but that shouldn't be too hard for you to deal with.

I'd probably just put a strip of fiber reinforced tape across the center on the bottom, but I'm a butcher

--Norm
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Old Jan 22, 2012, 03:49 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Norm,

The tip ballast is small.

I removed the right wing tip ballast and that lessened the roll. However you can see in photos 1 and 2 above that the left aileron is still deflected upward.

Removing the right wing ballast moves the CG toward the thrustline. As an experiment I will add ballast to the left tip until the roll force is gone. I suspect that will happen when the CG is on the thrustline. That would mean that the added wing area to the right of the thrustline is carrying the weight of the pod. In that case it really is asymmetrical.

My original assumption was that the CG would be at the half span point.

Tom
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Old Jan 22, 2012, 06:26 PM
Registered User
Joined Oct 2004
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Then the proper "cure" would be to increase the span of the right wing and decrease that of the left wing, I guess. Something for the next iteration?
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Old Jan 22, 2012, 06:37 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
That is essentially what happens when I move the CG left to the thrustline.

We can fondle the numbers when I get it balanced.

Tom
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Old Feb 12, 2012, 10:47 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
I added a ballast box to the left wing tip. I'll add lead shot until it does not require roll trim. It looks like the CG is going to approach the thrust line. It will be interesting to analyze the result.

Weather's bad, but hope to fly this weekend.

Tom
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Old Feb 16, 2012, 06:49 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Add span to the right panel

I did some sketches and played with the layout and came to the same conclusion as Norm in #125. I need to add span to the Pod side wing panel. So, I'm building a 7 inch section to add to the tip. I should be able to complete it by tomorrow and fly Saturday morning.

Tom
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Old Feb 16, 2012, 10:41 PM
internet gadfly
nmasters's Avatar
Colorado
Joined Aug 2006
2,186 Posts
That's bigger than I would have guessed.
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Old Feb 17, 2012, 12:34 AM
Grad student in aeronautics
United States, GA, Atlanta
Joined Oct 2010
464 Posts
To go along with the asymmetry theme, a winglet on the right tip would be interesting (I'm assuming you're looking for more lift on the right wing).
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Old Feb 17, 2012, 12:41 AM
internet gadfly
nmasters's Avatar
Colorado
Joined Aug 2006
2,186 Posts
That would add a jaunty touch
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Old Feb 17, 2012, 07:34 AM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Norm,

I probably overkilled it, but I'll have another data point. If it's too much I can trim the added section to the center rib.

I intend to add tip plates after I have good performance data. Be interesting to see if they make any difference.

Tom
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Old Feb 17, 2012, 03:54 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,661 Posts
Extension

Not perfect, but a reasonable match.

Tom
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