Recommended airfoil for Pattern-type model?
#1
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From: Nth Yorks, UNITED KINGDOM
Hi,
I'd like to have a go at designing & building my own aerobatic/Pattern type model so I was just wondering if there are any commonly used or preferred airfoil sections?
Any other advice or suggestions re. wing taper or root/tip sections would be much appreciated. I'd prefer something that was maybe limited aerobatically but stable (no tip stalling) - if you know what I mean.
Thanks guys!
I'd like to have a go at designing & building my own aerobatic/Pattern type model so I was just wondering if there are any commonly used or preferred airfoil sections?
Any other advice or suggestions re. wing taper or root/tip sections would be much appreciated. I'd prefer something that was maybe limited aerobatically but stable (no tip stalling) - if you know what I mean.
Thanks guys!
#2
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From: USA
Let me 'take pity on you' as no one else has seen fit to answer your question.
You really have two questions (or design parameters) under one label i.e. airfoil.
Any of the NACA 00 series will do fine but for pattern work try to go as low in percentage thickness as you can. Try NACA0012 or NACA 0010.
Now, for the 'no tip stall' requirement-----that really is a question of wing loading and aspect ratio rather than airfoil (we're dealing in generalities here). Keep the wing loading as light as possible i.e. 20 to 25 ounces for a 700 to 900 sq. in. wing. While the higher taper ratios give a sexier appearance a shorter span with a wider chord will give you the stability you seek while being able to handle about any aerobatic maneuver you care to throw at it-----particularly the higher Alpha stuff (ugly 3D)----(just personal preference on my part).
Stick with these generalities with a CG no further aft than 30 to 35% and you won't be bitten. And, interestingly enough, with plenty of power on tap it will give a pretty fair accounting of itself in the aerobatic regime. Please note the 'tip stall' label is a generality that describes a myriad of design deficiencies as well as pilot errors which may or may not be 'tip stall' in fact. It is just that every time a model stalls and goes in to one side everyone yells 'TIP STALL' which probably isn't accurate two thirds of the time.
That is another very long explanation which I can give you the URL for should you be interested. In the meantime the above design parameters should get you where you say you wish to go.
There are many others on this forum more qualified than I (and a few less qualified) but neither variety has answered you so perhaps my comments will suffice.
You really have two questions (or design parameters) under one label i.e. airfoil.
Any of the NACA 00 series will do fine but for pattern work try to go as low in percentage thickness as you can. Try NACA0012 or NACA 0010.
Now, for the 'no tip stall' requirement-----that really is a question of wing loading and aspect ratio rather than airfoil (we're dealing in generalities here). Keep the wing loading as light as possible i.e. 20 to 25 ounces for a 700 to 900 sq. in. wing. While the higher taper ratios give a sexier appearance a shorter span with a wider chord will give you the stability you seek while being able to handle about any aerobatic maneuver you care to throw at it-----particularly the higher Alpha stuff (ugly 3D)----(just personal preference on my part).
Stick with these generalities with a CG no further aft than 30 to 35% and you won't be bitten. And, interestingly enough, with plenty of power on tap it will give a pretty fair accounting of itself in the aerobatic regime. Please note the 'tip stall' label is a generality that describes a myriad of design deficiencies as well as pilot errors which may or may not be 'tip stall' in fact. It is just that every time a model stalls and goes in to one side everyone yells 'TIP STALL' which probably isn't accurate two thirds of the time.
That is another very long explanation which I can give you the URL for should you be interested. In the meantime the above design parameters should get you where you say you wish to go.
There are many others on this forum more qualified than I (and a few less qualified) but neither variety has answered you so perhaps my comments will suffice.
#3
onewasp -you made a huge error!!
"Tip stall!" is incorrect 95% of the time ------
We found the thinner and ligher the wing -the better it all became.
The old crappola about " thick high lift wings" is just that.
"Tip stall!" is incorrect 95% of the time ------
We found the thinner and ligher the wing -the better it all became.
The old crappola about " thick high lift wings" is just that.
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From: USA
Sorry 'bout that error Mr. Hanson!
I was thinking higher but thought ----well, with 'no name' in aerodynamics I'll put it where most would accept it. As you well know your percentage is much more accurate.
I was thinking higher but thought ----well, with 'no name' in aerodynamics I'll put it where most would accept it. As you well know your percentage is much more accurate.



