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Old Nov 13, 2006, 01:37 PM
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Hello,

I try to convert the PDF to DXF (to cut BlingBling on my little CNC cutting tool) but i have some problems with scale after conversion.
No pb with the wingspan, i would need other dimensions.
Could you help me ?



Thank you.

Powerbook.
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Old Nov 13, 2006, 02:51 PM
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Quote:
Originally Posted by power
The design is well thought out, it can be built incredibly light yet rigid. The moments are perfect for component placement in realation to C.G. I was a bit worried about hitting C.G. using a 12 gram motor with a superlight pack. But it came out perfect



Mike
What is your setting for C.G?
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Old Dec 02, 2006, 10:41 AM
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im looking at these plans and notice a strange right thrust. is this an oversight or am i missing somthing? i usualy build to have a 0-0 motor set up so this seems strange to me....
ededge2002
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Old Dec 02, 2006, 11:54 AM
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Eagle Lake, Minnesota
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Quote:
Originally Posted by lastuaja
What is your setting for C.G?
I am flying my Bling at 185 mm back from the nose (center) of the fuse. This is about 6 mm "aft" from the plan C.G. I like the way it flys so I left it.



Mike
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Old Dec 02, 2006, 12:01 PM
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Eagle Lake, Minnesota
Joined Apr 2003
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Quote:
Originally Posted by Powerbook
Hello,

I try to convert the PDF to DXF (to cut BlingBling on my little CNC cutting tool) but i have some problems with scale after conversion.
No pb with the wingspan, i would need other dimensions.
Could you help me ?



Thank you.

Powerbook.

I just measured my plans and I got 762 mm on the length and 206 mm on the height. Hope this helps.

Mike
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Old Dec 06, 2006, 01:56 PM
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Hi Power,

Thank you !
I cut a BlingBling, flight great with a MicroDan 2003-F3P, it's a dream ;-)

Powerbook.
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Old Dec 06, 2006, 03:39 PM
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im looking at these plans and notice a strange right thrust. is this an oversight or am i missing somthing? i usualy build to have a 0-0 motor set up so this seems strange to me....
ededge2002
Are you kidding or are you serious?.......
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Old Dec 06, 2006, 04:08 PM
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Originally Posted by matchlessaero
Are you kidding or are you serious?.......
im being serious there looks to be a considerable amount of right thrust on the horizontal part of the fuse... it might just be me but it looks like the front of it is not at a 90deg angle.

ededge2002
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Old Dec 06, 2006, 04:10 PM
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edge is right look at it closely.
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Old Dec 06, 2006, 04:15 PM
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Australia, QLD, Forest Lake
Joined Dec 2003
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Quote:
Originally Posted by ededge2002
im being serious there looks to be a considerable amount of right thrust on the horizontal part of the fuse... it might just be me but it looks like the front of it is not at a 90deg angle.

ededge2002
yeeesssssss........it has right thrust. What is so strange about this??

It's probably needed for the correct thrust line in hover, apart from all the usual right thrust reasons, (do we really have to revisit that one...??????)

I'm with Matchless, I thought you were kidding with your question.
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Old Dec 06, 2006, 04:26 PM
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Eagle Lake, Minnesota
Joined Apr 2003
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Quote:
Originally Posted by Powerbook
Hi Power,

Thank you !
I cut a BlingBling, flight great with a MicroDan 2003-F3P, it's a dream ;-)

Powerbook.

Your welcome Glad to hear you got one flying. The plane almost flys itself. I love it!!


ededge2002, hard to believe that you have not seen right thrust in model aircraft before, it is very common. It is to compensate for "P" factor and or motor torque. In a perfect setup, adding throttle and not having to feed in rudder to keep the aircraft in a straight heading is what the designers are after. In pattern, smooth, perfect transitions are desired so the less input from the pilot the better.

Mike
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Old Dec 06, 2006, 05:57 PM
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ok sorry for my stupidness but ive never built right thrust into a foamy lol i guess i just fly it out..... i do know the reasons of right thrust (started flying in 1984) but never bothered to apply it to foamys ...... (you know that thing where right thrust is backwards upside down....(grin!)) also i guess different prop/motor combos would need different amounts of thrust angle because of the different P factor.

thanks
ededge2002

"Kit designers try to help by building right thrust into the
engine mount in an attempt to counteract the P-factor. But the
yaw force is to the right when the plane is inverted, so the builtin
right thrust just makes the problem worse, and it would
require a lot of drag-producing left-rudder correction to
overcome it. Understanding the source of these forces and
learning to give the correct control inputs result in lower overall
drag through maneuvers."

(pg 3 paragraph 3)
http://members.aol.com/KMyersEFO/aerobat.pdf
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Old Dec 06, 2006, 06:07 PM
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ok sorry for my stupidness but ive never built right thrust into a foamy lol i guess i just fly it out
Not stupidness, and I did not mean to sound condescending. Please accept my apologies if I did.
However, I've only flown 2 foamy designs ever that did not need right thrust. Everything else that I've ever designed or flown required right thrust to track correctly......
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Old Dec 06, 2006, 07:13 PM
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Ireland, Kildare, Leixlip
Joined May 2002
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Quote:
Originally Posted by ededge2002
ok sorry for my stupidness but ive never built right thrust into a foamy lol i guess i just fly it out..... i do know the reasons of right thrust (started flying in 1984) but never bothered to apply it to foamys ...... (you know that thing where right thrust is backwards upside down....(grin!)) also i guess different prop/motor combos would need different amounts of thrust angle because of the different P factor.

thanks
ededge2002

"Kit designers try to help by building right thrust into the
engine mount in an attempt to counteract the P-factor. But the
yaw force is to the right when the plane is inverted, so the builtin
right thrust just makes the problem worse, and it would
require a lot of drag-producing left-rudder correction to
overcome it. Understanding the source of these forces and
learning to give the correct control inputs result in lower overall
drag through maneuvers."

(pg 3 paragraph 3)
http://members.aol.com/KMyersEFO/aerobat.pdf
I wouldn't necesarily agree with the P-factor/reversed inverted analysis. Most of the necessity for right thrust is often due to the distribution of fuselage area in the wake of the prop. The airflow in the wake rotates in the same direction as the prop. Since there's typically more side area above the thrustline behind the CG there's typically a net yawing effect to the left. This effect is dependent on the direction of propellor rotation and distribution of fuselage area so thrustline compensation will be equally effective inverted.

Aidan
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Old Dec 06, 2006, 08:40 PM
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Australia, QLD, Forest Lake
Joined Dec 2003
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Quote:
Originally Posted by matchlessaero
Not stupidness, and I did not mean to sound condescending. Please accept my apologies if I did.
However, I've only flown 2 foamy designs ever that did not need right thrust. Everything else that I've ever designed or flown required right thrust to track correctly......
My app's also. I just take it for granted that everything (conventional.... ) will need some right thrust to avoid carrying rudder trim (which is a can of worms on its own since this is airspeed dependant not power setting dependant, so not so good for cancelling/compensating for P-factor).
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