Delta wing COG ?
11-09-2010, 08:32 AM
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Delta wing COG ?
Morning...I just picked up a used delta wing. When I sit it on the ground it falls back onto its rear end. I would think that means it's tail heavy. Anyone know how to balance a wing?
Thanks
Thanks
11-09-2010, 01:52 PM
#3
RE: Delta wing COG ?
It may mean that the landing gear is not located where it is supposed to be.
Just balance it like a regular plane, on the wing.
Find the MAC (mean aerodynamic chord) as Mike's drawing indicates, mark the AC point (aerodynamic center at 25% of the MAC) and decide on the stability margin you want (10% recommended), the locate your CG and balance it.
Check this site:
http://adamone.rchomepage.com/index5.htm
Just balance it like a regular plane, on the wing.
Find the MAC (mean aerodynamic chord) as Mike's drawing indicates, mark the AC point (aerodynamic center at 25% of the MAC) and decide on the stability margin you want (10% recommended), the locate your CG and balance it.
Check this site:
http://adamone.rchomepage.com/index5.htm
11-09-2010, 10:08 PM
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RE: Delta wing COG ?
ORIGINAL: Lnewqban
Find the MAC (mean aerodynamic chord) as Mike's drawing indicates, mark the AC point (aerodynamic center at 25% of the MAC) and decide on the stability margin you want (10% recommended), the locate your CG and balance it.
Find the MAC (mean aerodynamic chord) as Mike's drawing indicates, mark the AC point (aerodynamic center at 25% of the MAC) and decide on the stability margin you want (10% recommended), the locate your CG and balance it.
On a rectangular wing, the MAC would be 25% back from the leading edge, which corresponds to where I have always seen it for "traditional" wings.
11-10-2010, 11:48 AM
#5
RE: Delta wing COG ?
ORIGINAL: SushiSeeker
You can use this formula to calculate CG for all wings, correct?
You can use this formula to calculate CG for all wings, correct?
ORIGINAL: SushiSeeker
On a rectangular wing, the MAC would be 25% back from the leading edge, which corresponds to where I have always seen it for ''traditional'' wings.
On a rectangular wing, the MAC would be 25% back from the leading edge, which corresponds to where I have always seen it for ''traditional'' wings.
Now granted, the MAC on a straight wing is basically any line drawn from LE to TE, but it is incorrect to say, "the MAC would be 25% back from the leading edge" because the MAC is perpendicular to the LE not parallel to it.
11-10-2010, 01:03 PM
#6
RE: Delta wing COG ?
Every wing follows this principle.
Just to clarify:
Any irregular wing planform can be converted to an equivalent rectangular planform.
Since an irregular wing planform has many different chords, the chord of that equivalent rectangular planform will have the length of the mean chord of the irregular wing (the length of all the chords divided by the number of different chords).
That mean chord is named mean aerodynamic chord or MAC.
Regarding the 25% point, it is called the neutral point (NP) of any airfoil.
At that point, the pitch moment is always zero.
This animation explains that very clearly (look for center of pressure):
http://www.geistware.com/rcmodeling/...rorgravity.htm
Just to clarify:
Any irregular wing planform can be converted to an equivalent rectangular planform.
Since an irregular wing planform has many different chords, the chord of that equivalent rectangular planform will have the length of the mean chord of the irregular wing (the length of all the chords divided by the number of different chords).
That mean chord is named mean aerodynamic chord or MAC.
Regarding the 25% point, it is called the neutral point (NP) of any airfoil.
At that point, the pitch moment is always zero.
This animation explains that very clearly (look for center of pressure):
http://www.geistware.com/rcmodeling/...rorgravity.htm
11-10-2010, 02:41 PM
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RE: Delta wing COG ?
ORIGINAL: shanet75
Morning...I just picked up a used delta wing. When I sit it on the ground it falls back onto its rear end. I would think that means it's tail heavy. Anyone know how to balance a wing?
Thanks
Morning...I just picked up a used delta wing. When I sit it on the ground it falls back onto its rear end. I would think that means it's tail heavy. Anyone know how to balance a wing?
Thanks
Is it an electric, and do you have the battery out?
