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Old Jun 16, 2014, 12:29 PM
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DustBen's Avatar
United States, NE, Kearney
Joined Dec 2011
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Quote:
Originally Posted by billisfree View Post
It WILL work. There's not a lot of difference between a crude airfoil and a precise one.
"It WILL work".

Eating crappy boxed mac n cheese with canned vegetables will work too.

Some of us prefer good stuff.
It's all a matter of what your standards are.
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Old Jun 16, 2014, 12:40 PM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
Joined Mar 2006
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Quote:
Originally Posted by failboat View Post
I suspect the truth is somewhere between BIF and JPF's posts.... as evidenced by the nutball like planes I have witnessed which are just a flat circle of dtf and a "tunnel" for the electronics.... of course they drop like a rock once they lose airspeed.
Yes, as i said in my final comment:
"But of course they all 'work' insomuch as they all fly. You would have to come up with something really crazy to not be able to fly at all."

For sports type models where ultimate flight duration or all out performance are not really important, and there is generous power available to make up for aerodynamic inefficiencies, then within reason pretty much anything will fly acceptably well.

But don't let this fool you into concluding that all airfoils fly the same, they don't.
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Old Jun 16, 2014, 08:41 PM
Wake up, feel pulse, be happy!
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United States, AK, Fairbanks
Joined Aug 2009
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There's a difference between flying and performing. A look around RCG's Scratchbuilt Foamies forum will give you a glimpse at some of the least efficient flying machines ever made... but fly they do. If all you want is a model that will move through the air, there are very few actual requirements for making it happen. It takes a lot more specialization if you want your model to perform really well at some specific task - for example, thermal gliders and 3D models tend to use very different airfoil sections, none of which were chosen randomly.

Keep in mind that airfoil choice is only one of a large number of factors affecting how your model flies. Even a perfectly-optimized airfoil won't help you if the plane is unreasonably heavy for its size, or if the CG is way off, or if the power system isn't right... and so on. There's not a whole lot needed to get a plane in the air, but there are loads of ways to screw up.
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Old Jun 16, 2014, 08:48 PM
Wake up, feel pulse, be happy!
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United States, AK, Fairbanks
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Quote:
Put enough motor on the front and airfoil be damned.
This strategy always sounds great to those who've never actually tried it
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Old Jun 16, 2014, 10:59 PM
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Referring to post 18 above.

"Performing" doesn't necessarily imply " to the nth degree".
On the other hand, as C4 says, there is a reason planes have different airfoils.

Going back thru the history of really great models of the recent 40 years, from all spectrums of flying from sailplanes, slopers, sport, pattern, and "balls-out" designs, each category's airfoils are different. But within each group, there are very similar airfoils that deliver superb results.

Matching a good competent airfoil to the flight profile pays off.

Really good designs don't suffer "tips stalls", or "hot and fast" approaches, or other nasty tendencies. The planes last a long time in competent hands.
Words like, "rock solid", and "on rails", and "forgiving" are often the descriptions used.

My feeling is... if I'm going to have a model airplane, it's going to be something worth having. They're investments I have and keep for years. I let other good pilots in the club fly 'em; they love 'em.
They "order" planes from me... planes with competent performance attributes.

Again. As I said above... It's about "standards".
If you want a POS to ram thru the window on the outhouse door...
Or you want something to bring out the best of your flying capabilities.
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Old Jun 18, 2014, 06:18 PM
What tree?
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Yucca Valley, California
Joined Aug 2005
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Quote:
Originally Posted by C₄H₁₀ View Post
This strategy always sounds great to those who've never actually tried it
People have been flying flat pieces of coroplast for years.

A helicopter is living proof that with enough power you can hang anything on a prop. Lol.
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Old Jun 18, 2014, 06:34 PM
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United States, TX, Fort Worth
Joined Jun 2000
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Quote:
Originally Posted by Rampage View Post
People have been flying flat pieces of coroplast for years.
Yes, but I think the Coroplast flyers all suffer from secret shame. Flat Depron and EPP are ok, but you have to have SOME pride...

Actually nothing wrong at all with a flat no camber airfoil for certain types of lightly loaded models. The problem is when people start thinking that they are a universal solution for all models.
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Old Jun 19, 2014, 12:35 AM
222 km/hr Parkjet flyer
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Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
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Quote:
Originally Posted by Rampage View Post
People have been flying flat pieces of coroplast for years.

A helicopter is living proof that with enough power you can hang anything on a prop. Lol.
I remember in early 80's ... I had a Mirage 2000 ... (two actually) :



Boy was that wing thick at max point. Powered by ST G60 with pipe.

Was flying it one day when another turned up with an F15 flat-plate job built in 3/16th balsa ... powered by Irvine 20.

This was a model that had been featured in a UK magazine and promoting the flat-plate form. There was all the BS about no aerofoil form, how bad it would stall, the excessive angle of attack it would need etc. etc.

That F15 took to the skies .. alongside my beast of a Mirage .. Result ? I went out and bought a load of 3/16th sheet to build one myself !

The argument about flyability has raged for decades ...

I have an F15 in 6mm Depron ... and that little beaut goes like stink .. well it had to - it's a Schumate design !!



Nigel
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Old Jun 19, 2014, 12:59 AM
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United States, AK, Fairbanks
Joined Aug 2009
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Quote:
People have been flying flat pieces of coroplast for years.

A helicopter is living proof that with enough power you can hang anything on a prop. Lol.
I've flown (and built, and designed) quite a fair number of models with flat airfoils, or else airfoils that any reasonable person would consider "flat". A bunch of them have had unbelievable amounts of power.

... Take note, however, that a helicopter's blades involve their own specialized airfoils, as do the props we hang those flat models from Again, it's the difference between just making something fly and making it fly better. Shoving in more power becomes either impossible or blindly impractical... like, yeah, you COULD build a helicopter with flat-plate blades and jam in a bigger engine to make up for the lost efficiency, but that's a losing game right from the start.
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Old Jun 19, 2014, 02:47 AM
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Staffs, UK
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Interesting that so many people spend so long analysing something without really asking the first basic and essential question. What is the wing supposed to work for ?

If it was for a competition glider it would be terrible. If it was for a general aerobatic model with plenty of power it would be fine. If it was for a trainer then zero(-ish) camber is probably not ideal.

Whenever you're talking about the quality of something it's worth remembering that the purpose is vital. My old Junior 60 works fine for casual lazy days flying. If I wanted it to win a pylon race...it wouldn't work at all .

Steve
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Old Jun 19, 2014, 03:56 AM
222 km/hr Parkjet flyer
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Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
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Quote:
Originally Posted by slipstick View Post
Interesting that so many people spend so long analysing something without really asking the first basic and essential question. What is the wing supposed to work for ?

If it was for a competition glider it would be terrible. If it was for a general aerobatic model with plenty of power it would be fine. If it was for a trainer then zero(-ish) camber is probably not ideal.

Whenever you're talking about the quality of something it's worth remembering that the purpose is vital. My old Junior 60 works fine for casual lazy days flying. If I wanted it to win a pylon race...it wouldn't work at all .

Steve
Fair enough ... go back to my post about Slopers that Chris Foss designed ... covers just that.

But the thread has taken a logical progression from the OP's simple question - Will this aerofoil work ? With no specific about style or form of flying .. simply - will it work. The answer is Yes. Rest is just chat.

Nigel
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Old Jun 19, 2014, 04:39 AM
Complete RC Idiot Savant
The Netherlands
Joined Nov 2009
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Quote:
Originally Posted by solentlife View Post
Given that various military fighters today have wing loadings higher than an iron manhole cover ............. that is certainly true.

Nigel
Now my imaginative mind immediately visualizes the ballast hatch cover I was opening the other day, with a big glow engine and some RC strapped to it....

LOL

Brgds, Bert
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