Modern Airfoil for 28% plus... Extreme Aerobats
03-10-2008, 09:13 AM
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Modern Airfoil for 28% plus... Extreme Aerobats
In as much as the selig 8036 airfoil is considered one of the best choices for large scale warbirds for its forgiving stall & high wing load capability.....
What is considered the best choice "modern" thin airfoil for those 28 to 35% aerobats like the edge 540 , extra300 &Yak 54's that allow them to snap, do harriers & good high speed flight so easily??
What is considered the best choice "modern" thin airfoil for those 28 to 35% aerobats like the edge 540 , extra300 &Yak 54's that allow them to snap, do harriers & good high speed flight so easily??
03-10-2008, 10:15 AM
#2
RE: Modern Airfoil for 28% plus... Extreme Aerobats
basically -it is almost all in wing loading -
as for the best responding foils - --as thin as you can make em with out bending or breaking -is the best .
This ain't theory but actual application and in some cases gradual reduction in thickness and high point changes . _I built many of these size types . a foam core 1 /16" balsa sheeted and film covered wing - -seems best practical choice
as for airfoil - 12% root and 9-12% tip is about a practical limit. a low aspect ratio also helps a lot -the lower the better .
as for the best responding foils - --as thin as you can make em with out bending or breaking -is the best .
This ain't theory but actual application and in some cases gradual reduction in thickness and high point changes . _I built many of these size types . a foam core 1 /16" balsa sheeted and film covered wing - -seems best practical choice
as for airfoil - 12% root and 9-12% tip is about a practical limit. a low aspect ratio also helps a lot -the lower the better .
03-18-2008, 11:38 AM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
Well, I'm leaning towards the naca 0012 airfoil for root & tip, But I have also noticed that those TOC yaks have rather sharp LE.. (so it stalls faster??) thinking thay may be on of the eppler airfoils. possibly a eppler 168
Started 3D modelling a yak 54 in 3D & am now at the airfoil selection point. What airfoil do these carden yaks use??
Started 3D modelling a yak 54 in 3D & am now at the airfoil selection point. What airfoil do these carden yaks use??
03-19-2008, 01:52 AM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: reaaz
Well, I'm leaning towards the naca 0012 airfoil for root & tip, But I have also noticed that those TOC yaks have rather sharp LE.. (so it stalls faster??) thinking thay may be on of the eppler airfoils. possibly a eppler 168
Started 3D modelling a yak 54 in 3D & am now at the airfoil selection point. What airfoil do these carden yaks use??
Well, I'm leaning towards the naca 0012 airfoil for root & tip, But I have also noticed that those TOC yaks have rather sharp LE.. (so it stalls faster??) thinking thay may be on of the eppler airfoils. possibly a eppler 168
Started 3D modelling a yak 54 in 3D & am now at the airfoil selection point. What airfoil do these carden yaks use??
All of which is to say that I don't know because I'm not into big pattern/3D models but I do know that this is a "fashion" sort of deal. Copy what the other models in the same size and weight range are using. Copy the ones that consistently come out in the top ten positions.
03-19-2008, 09:23 AM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
yes I do wish to use/copy a proven large scale airfoil... problem is I haven't been able to find out what the carden & somenzi yaks, or those 40% extra's are using.
Thats why i posted here, because i hope someone would be able to tell me or if they had one of those kits...... scan a wing rib or two for me. lol
Thats why i posted here, because i hope someone would be able to tell me or if they had one of those kits...... scan a wing rib or two for me. lol
03-19-2008, 09:58 AM
#10
RE: Modern Airfoil for 28% plus... Extreme Aerobats
The airfoils used on the BEST performance 3D/IMAC/aerobatic stuff follow a very simple rule: Make the airfoil as strong as possible yet as light as possible
This boils down to : make it as thin as practical .
If you exceed this - it will break.
The strongest is still a foam core with a well bonded balsa skin.
Some carbon wings are close but still not as good as weight in the skin is higher.
also they need some internal bracing -always.
Again - about a 12% root section is minimum
--but up to 15% at the root makes little if any performance difference
thetips tho ---a different matter - down to 8-9% is good
Also the thicker the root - the thinner the tip can be - a simple mater of strength and how it distributes
If you think you can make the wing thinner or lighter with built up methods - go ahead - You may find tho that ANY stress riser ( weak spots) will show up --unexpectedly
as for the best shape (airfoil)
not worth worrying about . just make it smooth and within the parameters seen in the avove drawings. Tho you may doubt it --- the big problem is in keeping it all rigid and flutter free as it gets lighter .
be it a model or the real thing
Full scale Sukhoi's had some structural problems
also some of the latest Sukhoi models - same problem --the designers relied on glue joints at critical root attchment points and when these loosened up- the wings literally exploded.
Spend your time learning structures- this far more important than some imagined perfect airfoil
If you get really good at light structures -you will then be able to make the betst aerobatic airfoils - thin -light and absolutely twist resistant.
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
This boils down to : make it as thin as practical .
If you exceed this - it will break.
The strongest is still a foam core with a well bonded balsa skin.
Some carbon wings are close but still not as good as weight in the skin is higher.
also they need some internal bracing -always.
Again - about a 12% root section is minimum
--but up to 15% at the root makes little if any performance difference
thetips tho ---a different matter - down to 8-9% is good
Also the thicker the root - the thinner the tip can be - a simple mater of strength and how it distributes
If you think you can make the wing thinner or lighter with built up methods - go ahead - You may find tho that ANY stress riser ( weak spots) will show up --unexpectedly
as for the best shape (airfoil)
not worth worrying about . just make it smooth and within the parameters seen in the avove drawings. Tho you may doubt it --- the big problem is in keeping it all rigid and flutter free as it gets lighter .
be it a model or the real thing
Full scale Sukhoi's had some structural problems
also some of the latest Sukhoi models - same problem --the designers relied on glue joints at critical root attchment points and when these loosened up- the wings literally exploded.
Spend your time learning structures- this far more important than some imagined perfect airfoil
If you get really good at light structures -you will then be able to make the betst aerobatic airfoils - thin -light and absolutely twist resistant.
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
03-19-2008, 10:55 AM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
Thanks for the info D. Hanson, Paul & bmatt, thus sofar i am thinking of using the Eppler 168 (12.45% thk) for the root & about a 10% version of the eppler for the tip (don't see any 10% version of the e168 series on the UIUC airfoil cordinate site) so i may have to scale it. And yes you have convinced me to go with a foam cored/balsa sheeted & glassed wing.
Any advice on how not to end up designing a wing/plane that lands as notoriously as a CAP
Any advice on how not to end up designing a wing/plane that lands as notoriously as a CAP
03-19-2008, 12:08 PM
#12
RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: reaaz
Thanks for the info D. Hanson, Paul & bmatt, thus sofar i am thinking of using the Eppler 168 (12.45% thk) for the root & about a 10% version of the eppler for the tip (don't see any 10% version of the e168 series on the UIUC airfoil cordinate site) so i may have to scale it. And yes you have convinced me to go with a foam cored/balsa sheeted & glassed wing.
Any advice on how not to end up designing a wing/plane that lands as notoriously as a CAP
Thanks for the info D. Hanson, Paul & bmatt, thus sofar i am thinking of using the Eppler 168 (12.45% thk) for the root & about a 10% version of the eppler for the tip (don't see any 10% version of the e168 series on the UIUC airfoil cordinate site) so i may have to scale it. And yes you have convinced me to go with a foam cored/balsa sheeted & glassed wing.
Any advice on how not to end up designing a wing/plane that lands as notoriously as a CAP
03-19-2008, 01:26 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: dick Hanson
The airfoils used on the BEST performance 3D/IMAC/aerobatic stuff follow a very simple rule: Make the airfoil as strong as possible yet as light as possible
This boils down to : make it as thin as practical .
...
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
The airfoils used on the BEST performance 3D/IMAC/aerobatic stuff follow a very simple rule: Make the airfoil as strong as possible yet as light as possible
This boils down to : make it as thin as practical .
...
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
Another requirement is for the wing to have a sharp, well defined stall. This is because modern aerobatic routines put a lot of emphasis on maneuvers which consists of departures, including snap rolls, spins, and lomcevaks. Look for airfoils that have a fairly steep adverse pressure gradient over the rear part of the airfoil and where the chordwise location of the upper surface separation point moves forward quite sharply at a certain angle of attack. NACA 00XX airfoils are far from ideal in this respect, the separation point moves smoothly forward with increasing angle of attack, which is a good for touring aircraft, but not necessarily for aerobatic aircraft.
Also the airfoil should have a high Cl-max in order for the wing to provide high lift to generate the high load factors required for aerobatic maneuvers, even at fairly low speeds. For a given shape of a symmetrical airfoil a thickness of 12-15% usually provides the maximum Cl.
Also worth having a look at is the drag at high angle of attack (AOA) which should be as low as possible. This is more important than low drag at low AOA.
Edit: I forgot to give mention that Eppler 472 with a truncated (blunt) trailing edge has been succesfully used in full scale aerobatic aircraft (Extra, Edge etcetera). The trick is to find an airfoil that have similar characteristics to the Eppler 472 (blunt TE) at the lower Reynolds numbers of our model aircraft. For a large scale aerobats that operate at reasonably high Reynolds number it may well be that the E472 is the airfoil of choice.
03-19-2008, 02:35 PM
#15
RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: Red B.
Dick, I fully agree with you that strength and weight are of utmost importance, but I do not agree that one should not neccesarily strive for a thin wing. A thick wing usually has higher drag which is beneficial in downlines where it prevents excessive speed build-up. Modern aerobatic aircraft do not achieve high speeds as a result of low drag, instead they rely on high powered engines.
Another requirement is for the wing to have a sharp, well defined stall. This is because modern aerobatic routines put a lot of emphasis on maneuvers which consists of departures, including snap rolls, spins, and lomcevaks. Look for airfoils that have a fairly steep adverse pressure gradient over the rear part of the airfoil and where the chordwise location of the upper surface separation point moves forward quite sharply at a certain angle of attack. NACA 00XX airfoils are far from ideal in this respect, the separation point moves smoothly forward with increasing angle of attack, which is a good for touring aircraft, but not necessarily for aerobatic aircraft.
Also the airfoil should have a high Cl-max in order for the wing to provide high lift to generate the high load factors required for aerobatic maneuvers, even at fairly low speeds. For a given shape of a symmetrical airfoil a thickness of 12-15% usually provides the maximum Cl.
Also worth having a look at is the drag at high angle of attack (AOA) which should be as low as possible. This is more important than low drag at low AOA.
Edit: I forgot to give mention that Eppler 472 with a truncated (blunt) trailing edge has been succesfully used in full scale aerobatic aircraft (Extra, Edge etcetera). The trick is to find an airfoil that have similar characteristics to the Eppler 472 (blunt TE) at the lower Reynolds numbers of our model aircraft. For a large scale aerobats that operate at reasonably high Reynolds number it may well be that the E472 is the airfoil of choice.
ORIGINAL: dick Hanson
The airfoils used on the BEST performance 3D/IMAC/aerobatic stuff follow a very simple rule: Make the airfoil as strong as possible yet as light as possible
This boils down to : make it as thin as practical .
...
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
The airfoils used on the BEST performance 3D/IMAC/aerobatic stuff follow a very simple rule: Make the airfoil as strong as possible yet as light as possible
This boils down to : make it as thin as practical .
...
You simply can NOT make the airfoil too thin -or too light - it is a practical impossibility
Another requirement is for the wing to have a sharp, well defined stall. This is because modern aerobatic routines put a lot of emphasis on maneuvers which consists of departures, including snap rolls, spins, and lomcevaks. Look for airfoils that have a fairly steep adverse pressure gradient over the rear part of the airfoil and where the chordwise location of the upper surface separation point moves forward quite sharply at a certain angle of attack. NACA 00XX airfoils are far from ideal in this respect, the separation point moves smoothly forward with increasing angle of attack, which is a good for touring aircraft, but not necessarily for aerobatic aircraft.
Also the airfoil should have a high Cl-max in order for the wing to provide high lift to generate the high load factors required for aerobatic maneuvers, even at fairly low speeds. For a given shape of a symmetrical airfoil a thickness of 12-15% usually provides the maximum Cl.
Also worth having a look at is the drag at high angle of attack (AOA) which should be as low as possible. This is more important than low drag at low AOA.
Edit: I forgot to give mention that Eppler 472 with a truncated (blunt) trailing edge has been succesfully used in full scale aerobatic aircraft (Extra, Edge etcetera). The trick is to find an airfoil that have similar characteristics to the Eppler 472 (blunt TE) at the lower Reynolds numbers of our model aircraft. For a large scale aerobats that operate at reasonably high Reynolds number it may well be that the E472 is the airfoil of choice.
one I have not found any real differences in downlines with thick vs.thin airfoils Weight makes real difference here.
2 - I WANT max drag at high angles of attack- this is my "brakes" and I use it all the time
I also use power LOTS of power and literally go from stop to full acceleration when flynig goofy stuff.
That's all -
03-19-2008, 03:01 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: dick Hanson
Hope you don't mind if I disagree-on the drag thing
one I have not found any real differences in downlines with thick vs.thin airfoils Weight makes real difference here.
2 - I WANT max drag at high angles of attack- this is my "brakes" and I use it all the time
I also use power LOTS of power and literally go from stop to full acceleration when flynig goofy stuff.
That's all -
Hope you don't mind if I disagree-on the drag thing
one I have not found any real differences in downlines with thick vs.thin airfoils Weight makes real difference here.
2 - I WANT max drag at high angles of attack- this is my "brakes" and I use it all the time
I also use power LOTS of power and literally go from stop to full acceleration when flynig goofy stuff.
That's all -
Some years ago I had the pleasure of listening to a talk by Walter Extra (father of the Extra series of full-size aerobats) on the design of aerobatic aircraft. During the talk he listed some of the most desirable properties of airfoils for aerobatic aircraft. Low drag at high AOA was second on the list after stall characteristics (as described in my previous post).
03-19-2008, 03:16 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: Red B.
Yes, there is quite a small difference in drag between a thick and a thin airfoil. Most of the drag emanates from the fuselage, landing gear etcetera.
Some years ago I had the pleasure of listening to a talk by Walter Extra (father of the Extra series of full-size aerobats) on the design of aerobatic aircraft. During the talk he listed some of the most desirable properties of airfoils for aerobatic aircraft. Low drag at high AOA was second on the list after stall characteristics (as described in my previous post).
ORIGINAL: dick Hanson
Hope you don't mind if I disagree-on the drag thing
one I have not found any real differences in downlines with thick vs.thin airfoils Weight makes real difference here.
2 - I WANT max drag at high angles of attack- this is my "brakes" and I use it all the time
I also use power LOTS of power and literally go from stop to full acceleration when flynig goofy stuff.
That's all -
Hope you don't mind if I disagree-on the drag thing
one I have not found any real differences in downlines with thick vs.thin airfoils Weight makes real difference here.
2 - I WANT max drag at high angles of attack- this is my "brakes" and I use it all the time
I also use power LOTS of power and literally go from stop to full acceleration when flynig goofy stuff.
That's all -
Some years ago I had the pleasure of listening to a talk by Walter Extra (father of the Extra series of full-size aerobats) on the design of aerobatic aircraft. During the talk he listed some of the most desirable properties of airfoils for aerobatic aircraft. Low drag at high AOA was second on the list after stall characteristics (as described in my previous post).
A local flyer has a Pitts 12 which will hover (full scale - big ol radial engine) - this design is probably as high as any full scale prop driven aerobat and thrust to weight is about 1-1
It's all a big compromise.
03-19-2008, 11:26 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
There's the efficiency of the airframe and then there's the reality of the flight task. More and more aerobatics is not as much about airframe efficiency as it is about the show. Red, you're still locked to the idea that the airframe has to provide efficiency while Dick is taking a far more pragmatic "in the trenches" stance. I dont' fly pattern but I've seen enough of the stuff posted here to realize that these days very little about pattern flying is efficiency in the model itself.
There's other drag factors that work with the actual flight pattern to account for. The drag of the prop disc is quite "parachute" like and that along with things like bulky landing gear will be a far better downline brake than the wing would be even if you do go to a thicker 12 to 15% airfoil. And generally along with that sort of thickness comes a stall that is delayed and softer than the need for the departure maneuvers will demand. Again the pragmatic stance comes out ahead. It's not about fiding the best airfoil for flying, it's about finding the best airfoil to do the maneuvers that need to be done. The two are not all that closely related as "flying" during many of those maneuvers is not required nor is it desireable.
There's other drag factors that work with the actual flight pattern to account for. The drag of the prop disc is quite "parachute" like and that along with things like bulky landing gear will be a far better downline brake than the wing would be even if you do go to a thicker 12 to 15% airfoil. And generally along with that sort of thickness comes a stall that is delayed and softer than the need for the departure maneuvers will demand. Again the pragmatic stance comes out ahead. It's not about fiding the best airfoil for flying, it's about finding the best airfoil to do the maneuvers that need to be done. The two are not all that closely related as "flying" during many of those maneuvers is not required nor is it desireable.
03-20-2008, 03:23 AM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
ORIGINAL: BMatthews
There's the efficiency of the airframe and then there's the reality of the flight task. More and more aerobatics is not as much about airframe efficiency as it is about the show. Red, you're still locked to the idea that the airframe has to provide efficiency while Dick is taking a far more pragmatic "in the trenches" stance. I dont' fly pattern but I've seen enough of the stuff posted here to realize that these days very little about pattern flying is efficiency in the model itself.
There's other drag factors that work with the actual flight pattern to account for. The drag of the prop disc is quite "parachute" like and that along with things like bulky landing gear will be a far better downline brake than the wing would be even if you do go to a thicker 12 to 15% airfoil. And generally along with that sort of thickness comes a stall that is delayed and softer than the need for the departure maneuvers will demand. Again the pragmatic stance comes out ahead. It's not about fiding the best airfoil for flying, it's about finding the best airfoil to do the maneuvers that need to be done. The two are not all that closely related as "flying" during many of those maneuvers is not required nor is it desireable.
There's the efficiency of the airframe and then there's the reality of the flight task. More and more aerobatics is not as much about airframe efficiency as it is about the show. Red, you're still locked to the idea that the airframe has to provide efficiency while Dick is taking a far more pragmatic "in the trenches" stance. I dont' fly pattern but I've seen enough of the stuff posted here to realize that these days very little about pattern flying is efficiency in the model itself.
There's other drag factors that work with the actual flight pattern to account for. The drag of the prop disc is quite "parachute" like and that along with things like bulky landing gear will be a far better downline brake than the wing would be even if you do go to a thicker 12 to 15% airfoil. And generally along with that sort of thickness comes a stall that is delayed and softer than the need for the departure maneuvers will demand. Again the pragmatic stance comes out ahead. It's not about fiding the best airfoil for flying, it's about finding the best airfoil to do the maneuvers that need to be done. The two are not all that closely related as "flying" during many of those maneuvers is not required nor is it desireable.
Stalling characteristics of an airfoil is of course dependent on the thickness of the airfoil, but so is the thickness distribution, which in turn determines the velocity and pressure distributions around the wing.
03-20-2008, 07:39 AM
#20
RE: Modern Airfoil for 28% plus... Extreme Aerobats
Red--Ya gotta fly em to understand what is really needed. The power to weight is really quite different, compared to the full scale stuff.
As a passing point --the full scale unlimited aerobatic guys pay close attention to what we do with our big aerobatic models
I wasn't guesing about the thin wing which allows instant snap/ stopping maneuvers . It is highly desireable.
In the slow speed super light aerobatics stuff - with wing areas of --400 squares and weights of 10 ounces - the dead flat wing sections provide stunning performance - smooth as glass thru super sharp turns yet giving no appearance of jerking as angles are instantly changed
again - you simply have to see it to understand how well it works -I was flabbergasted at first - till I did some of the modls
As a passing point --the full scale unlimited aerobatic guys pay close attention to what we do with our big aerobatic models
I wasn't guesing about the thin wing which allows instant snap/ stopping maneuvers . It is highly desireable.
In the slow speed super light aerobatics stuff - with wing areas of --400 squares and weights of 10 ounces - the dead flat wing sections provide stunning performance - smooth as glass thru super sharp turns yet giving no appearance of jerking as angles are instantly changed
again - you simply have to see it to understand how well it works -I was flabbergasted at first - till I did some of the modls
03-20-2008, 01:01 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
I think it's a case of full sized stuff stalls differently than our models. For example I talked some buddies into using the Eppler 474 airfoil on some control line combat models because they are supposed to stall less redily. For them it let them turn tighter and keep their speed up for flying combat. But for what we want on our pattern models this reluctance to stall in order to enter the snapping maneuvers is not going to be a good thing. Yet there are full sized aerobatic craft using this airfoil or ones from the same 47x "family" to excellent effect.
I know this isn't helping much but it's my recognition of the fact that the best aerobatic airfoil is going to be a balance between some good traits and some "bad" stalling traits that are desireable in THIS case just because you want a sharply defined stall. In fact I would think that the stalling traits of the airfoil should be matched to the wing loading. This would explain why so many posts are made about the nastiness of many Extra designs with their highly tapered wings yet Dick has no issues with the planform. I'm thinking that this is because those other problem planes were too heavy for the airfoil so they tend to stall when not wanted while Dick's Extras are lighter for their size and so the stall is workable even during landings. Those problem Extras may well work fine if the wing was suddenly swapped for one that has a higher Cl before stalling than what they have right now.
I know this isn't helping much but it's my recognition of the fact that the best aerobatic airfoil is going to be a balance between some good traits and some "bad" stalling traits that are desireable in THIS case just because you want a sharply defined stall. In fact I would think that the stalling traits of the airfoil should be matched to the wing loading. This would explain why so many posts are made about the nastiness of many Extra designs with their highly tapered wings yet Dick has no issues with the planform. I'm thinking that this is because those other problem planes were too heavy for the airfoil so they tend to stall when not wanted while Dick's Extras are lighter for their size and so the stall is workable even during landings. Those problem Extras may well work fine if the wing was suddenly swapped for one that has a higher Cl before stalling than what they have right now.
03-20-2008, 02:10 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
I totally agree with Dick! My aerobatic designs all feature the Eppler 168. They land easy and fly well....why? All have light wing loadings. I personally like the Eppler 168 but that is only because I kept the designs light weight and the wing loading reasonable.
Rob
Rob
03-20-2008, 02:30 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
Dick,
Living in Sweden where winters are long and cold, indoor flight has become very popular. Because of this I have plenty of experience with light weight depron aerobatic aircraft with very low wing loadings and flat airfoils. They fly at very low Reynolds number and therefore it is no surprise that flat airfoils works very well. I have not tried really thin airfoils on large scale aerobatic aircraft, but your experience make me want to try it. My next project will be a pair of really thin wings for my 25% Staudacher 600. Presently they are 12% thick.
Living in Sweden where winters are long and cold, indoor flight has become very popular. Because of this I have plenty of experience with light weight depron aerobatic aircraft with very low wing loadings and flat airfoils. They fly at very low Reynolds number and therefore it is no surprise that flat airfoils works very well. I have not tried really thin airfoils on large scale aerobatic aircraft, but your experience make me want to try it. My next project will be a pair of really thin wings for my 25% Staudacher 600. Presently they are 12% thick.
03-20-2008, 02:37 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
Smitty400, what span is your largest aerobatic plane (with Eppler 168) & what kind of aerobatics do you do with it?
On another note, the wing tip chord of the yak i'm designing is about 45% of the root chord of a SCALE yak outline... would such a great chordal difference cause it to be tip stall prone... eg same like a SCALE CAP??
On another note, the wing tip chord of the yak i'm designing is about 45% of the root chord of a SCALE yak outline... would such a great chordal difference cause it to be tip stall prone... eg same like a SCALE CAP??
03-20-2008, 04:59 PM
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RE: Modern Airfoil for 28% plus... Extreme Aerobats
My largest model has a wing span of 55 in. Wing loading is somewhere in the 16 oz/sq ft range. The model was designed as a sport/pattern aircraft. I've used this airfoil on some models as small as 28 in wing spans.