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Airfoil questions

Old 03-05-2010, 10:29 AM
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Default Airfoil questions

I just started cutting my own foam wings. I have an opportunity to have airfoils laser cut out of a 10" x 60" sheet of laminate for FREE... But I'm running out of time and have to get the final file to the guy...

I have to decide what airfoils to include, how large to make them ( wing root) and do I need one or two of each template.

The only wings I've cut so far are clark Y with one template and a wire attached to a pivot point. So all my wings so far are tapered wings. I believe I will need two templates to cut a straight wing...

My current file has 8 airfoils on it for a total of 8 tops and 8 bottoms.

Clark Y

E168 = symetrical for aerobatics

E197 = sport

205 = sport

E222 = glider

E214 = high lift sailplane

E184 = Flying wings and Delta

E230 = Flying wings and deltas

I guess the flying wings and deltas do not need two templates?

I'm thinking of making the templates with a 10 " root? ( I'm flying .40 - .60 glow)

Any suggestions on choices of airfoils and size would be appreciated...

I;m trying to get the most bang out of this laser cutting..

Thanks

Steve

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Old 03-05-2010, 04:10 PM
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Default RE: Airfoil questions

You're missing out on all the symetrical airfoil options for aerobatic or hotter and more neutral sport models.

NACA 0010, 0012 and 0015 for sure. To that I'd also add the Eppler 474 and a few Selig options such as the sailplane friendly 3021, 7037, 8020 and power scale model friendly 8036 and 8037.
Old 03-06-2010, 12:06 AM
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Default RE: Airfoil questions


ORIGINAL: Popriv
The only wings I've cut so far are clark Y with one template and a wire attached to a pivot point. So all my wings so far are tapered wings. I believe I will need two templates to cut a straight wing...
I've always used 2 templates,, straight or tapered.
You must be using a long wire
Old 03-06-2010, 06:23 AM
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Default RE: Airfoil questions


ORIGINAL: BMatthews

You're missing out on all the symetrical airfoil options for aerobatic or hotter and more neutral sport models.

NACA 0010, 0012 and 0015 for sure. To that I'd also add the Eppler 474 and a few Selig options such as the sailplane friendly 3021, 7037, 8020 and power scale model friendly 8036 and 8037.
H,mmmm, how best to utilize this 10" x 60" laminate sheet and free laser cutting?
(of course I can always cut my own templates later on, just wont be as nice)

I need to put together a file this weekend with the least amount of cuts. (cutting is $ by the inch..)

What would you suggest for:

SSCombat? ( current project) Cutting clark Y now. -

Slow thermal glider? -

Hotliner Glider? -

small slow flying park flyer? -

aerobatic / sport ? -

3/d ? -

These are the planes I think I would be interested in???
I'm guessing I'll be limited to 8 - 12 different airfoils?

Steve

Old 03-06-2010, 06:32 AM
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Default RE: Airfoil questions


ORIGINAL: scale only 4 me


ORIGINAL: Popriv
The only wings I've cut so far are clark Y with one template and a wire attached to a pivot point. So all my wings so far are tapered wings. I believe I will need two templates to cut a straight wing...
I've always used 2 templates,, straight or tapered.
You must be using a long wire
Wire is 7.5 feet. I have an 8' conduit pipe to create a bow, to keep constant wire tension. as long as you want a tapered wing you can get any size (smaller than the root) by moving the foam closer to the pivot point.

At some point I'll make an automatic cutter with two templates.

steve
Old 03-06-2010, 09:35 PM
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Default RE: Airfoil questions


SSCombat? ( current project) Cutting clark Y now. - Any combat flying suggest that the model will be upside down a good part of the time or pushing negative G. If the SS means "slope soaring" then you'll want a little bit better performance upright than inverted but not as radical as what the ClarkY is. I'm also assuming that they are intended to be rugged toss about models so you want the airfoil to be strong, that means fairly thick. So for that I'd probably go with a good ol' NACA 2412. Proven performance and happy enough upside down that there isn't a big penalty compared to using a full on symetrical airfoil.

Slow thermal glider? - Clark Y for simple and the Mark Drela AG24 Bubble Dancer airfoil for something higher tech. If you want REALLY slow as in calm days only but float forever but can't penetrate well then the old NACA 6409.

Hotliner Glider? - That's a tough one. THere's some really thin and slippery hotliner type airfoils. I'd want to find out what the latest F3B models are using for airfoils.

small slow flying park flyer? - A simple circular arc with the section being as thin as you can manage actually works well. But if you really must cut foam cores for them then something like the SOKOLOV or Benedek BE6356B that have been used with great success on many free flight rubber duration designs would not be bad options.

aerobatic / sport ? - That's easy. The NACA 0010, 0012 or 0015 already mentioned. Or for something with a delayed stall the Eppler 474 already mentioned

3/d ? - Flat plate for the small ones. No need for templates, just use depron. For larger models you'd need to pick an airfoil. Too many options. But a lot of them are using the same NACA symetrical options noted already.

Old 03-07-2010, 05:58 AM
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Default RE: Airfoil questions


ORIGINAL: BMatthews


SSCombat? ( current project) Cutting clark Y now. - Any combat flying suggest that the model will be upside down a good part of the time or pushing negative G. If the SS means ''slope soaring'' then you'll want a little bit better performance upright than inverted but not as radical as what the ClarkY is. I'm also assuming that they are intended to be rugged toss about models so you want the airfoil to be strong, that means fairly thick. So for that I'd probably go with a good ol' NACA 2412. Proven performance and happy enough upside down that there isn't a big penalty compared to using a full on symetrical airfoil.

Slow thermal glider? - Clark Y for simple and the Mark Drela AG24 Bubble Dancer airfoil for something higher tech. If you want REALLY slow as in calm days only but float forever but can't penetrate well then the old NACA 6409.

Hotliner Glider? - That's a tough one. THere's some really thin and slippery hotliner type airfoils. I'd want to find out what the latest F3B models are using for airfoils.

small slow flying park flyer? - A simple circular arc with the section being as thin as you can manage actually works well. But if you really must cut foam cores for them then something like the SOKOLOV or Benedek BE6356B that have been used with great success on many free flight rubber duration designs would not be bad options.

aerobatic / sport ? - That's easy. The NACA 0010, 0012 or 0015 already mentioned. Or for something with a delayed stall the Eppler 474 already mentioned

3/d ? - Flat plate for the small ones. No need for templates, just use depron. For larger models you'd need to pick an airfoil. Too many options. But a lot of them are using the same NACA symetrical options noted already.


Thanks, That gives me plenty of options, much appreciated!

Steve
Old 03-07-2010, 06:01 AM
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Default RE: Airfoil questions

Oh by the way, its Slow Survivable Combat = SSC .
light weight, 2.5 - 3 lbs and slow with a .15 engine.

It does sound like I would want something good at flying upside down...

Steve

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