Ideal 3D wing loading?
02-02-2006, 10:14 PM
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Ideal 3D wing loading?
I hear so much about wing loading and performance of the airplane that I decided to calculate the loading of common planes (all that I built and weighed myself, no fudge).Below are my results. However, it seems the heavier wing loading are what many consider the better flying airplanes.
What gives?
My personal flying indicates that the lower wing loading is best for flat spins (ie: Mayhem, UCD, Twist etc) and the higher wing loading is better for KE, precision etc.
Any comments?
UCD46 = 15.0 ozs./sq ft
Mayhem = 15.1
Ultra Stick 60 = 16.5
UCD 60 = 16.9
Ultra Stick Lite = 17.1
Twist = 17.3
Ultra Stick 40 = 19.1
Funtana 90 = 19.6
Harrier 3D = 20.7
EF Yak 68" = 21.4
Showtime = 22.4
As you can see, some of the heavier wing loading planes are considered by many the better flying airplanes. But clearly the lower wing loading planes are better at spins, especially flat spins.
Just wondering what others think.
Thanks
Barry
02-02-2006, 10:20 PM
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RE: Ideal 3D wing loading?
As you move to a larger plane the wing loading will go up. It just can't be helped. "Light wing loading" can really only be compared with similar sized planes. Take a 25% GP Patty Wagstaff Extra with a DA50 on it. Pretty heavy wing loading at say 30 or more. Take that same 30 on a 35% or 40% plane and you got something nice.
02-02-2006, 10:24 PM
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RE: Ideal 3D wing loading?
Hi Barry,
Just so you don't overlook--When you consider wing loading you also have to consider size as well. A larger plane that has the same wing loading as the smaller plane will fly easier.
http://www.centennialofflight.gov/es...s_no/DI114.htm
Just so you don't overlook--When you consider wing loading you also have to consider size as well. A larger plane that has the same wing loading as the smaller plane will fly easier.
Reynolds Number
The factor that is called the Reynolds number was discovered by Osborne Reynolds of the University of Manchester in 1883. This parameter is important in wind tunnel experiments since it relates to the aerodynamic properties of lifting surfaces (like airfoils) when extrapolating from small wind tunnel test models to full-size wings. Reynolds discovered that, if the same atmospheric pressure were used for experiments with wind tunnel models as a full-size aircraft would encounter under actual conditions, the experimental results would be invalid.
In order for results obtained with a scale model in wind tunnel experiments to be valid, the Reynolds number needs to be the same under wind tunnel conditions and in regular atmospheric conditions. The way to ensure this is to increase the air density inside the tunnel by the same proportion as the model is smaller than the full-size aircraft. In practical terms, if a model is 1/10 the size of a full-size aircraft, then the air density (the number of atmospheres) inside the tunnel must be increased by a factor of 10 to get wind tunnel results that are valid in regular atmospheric conditions with a full-size aircraft.
Reynolds discovered the ratio that has since been called the Reynolds number when examining fluid flow characteristics-how a liquid flows in a pipe or how air flows across an aircraft wing. He demonstrated that the motion of a fluid may be either laminar (in smooth layers) or turbulent, and that the change from a laminar flow to a turbulent flow can happen suddenly. The transition from a smooth laminar flow to a turbulent flow always occurred when the ratio ?VD/µ was the same, where ? = density of the fluid, V = velocity, D = pipe diameter, and µ = fluid viscosity. This ratio is now known as the Reynolds number. The variable that can be adjusted inside a wind tunnel is ?-its density, and it would be adjusted by the same proportion as the model is smaller than the actual aircraft: a 1/10th model would produce valid results if the atmospheric pressure in the wind tunnel were increased by a factor of 10.
In actual subsonic flight, airfoils with low Reynolds number flows are laminar and those with high Reynolds number flows are mostly turbulent, keeping in mind that the Reynolds number is the ratio between density, velocity, diameter, and viscosity (For an airfoil in flight rather than in a wind tunnel, D would be the distance between the leading and trailing edge called the chord length along a flow.)
The factor that is called the Reynolds number was discovered by Osborne Reynolds of the University of Manchester in 1883. This parameter is important in wind tunnel experiments since it relates to the aerodynamic properties of lifting surfaces (like airfoils) when extrapolating from small wind tunnel test models to full-size wings. Reynolds discovered that, if the same atmospheric pressure were used for experiments with wind tunnel models as a full-size aircraft would encounter under actual conditions, the experimental results would be invalid.
In order for results obtained with a scale model in wind tunnel experiments to be valid, the Reynolds number needs to be the same under wind tunnel conditions and in regular atmospheric conditions. The way to ensure this is to increase the air density inside the tunnel by the same proportion as the model is smaller than the full-size aircraft. In practical terms, if a model is 1/10 the size of a full-size aircraft, then the air density (the number of atmospheres) inside the tunnel must be increased by a factor of 10 to get wind tunnel results that are valid in regular atmospheric conditions with a full-size aircraft.
Reynolds discovered the ratio that has since been called the Reynolds number when examining fluid flow characteristics-how a liquid flows in a pipe or how air flows across an aircraft wing. He demonstrated that the motion of a fluid may be either laminar (in smooth layers) or turbulent, and that the change from a laminar flow to a turbulent flow can happen suddenly. The transition from a smooth laminar flow to a turbulent flow always occurred when the ratio ?VD/µ was the same, where ? = density of the fluid, V = velocity, D = pipe diameter, and µ = fluid viscosity. This ratio is now known as the Reynolds number. The variable that can be adjusted inside a wind tunnel is ?-its density, and it would be adjusted by the same proportion as the model is smaller than the actual aircraft: a 1/10th model would produce valid results if the atmospheric pressure in the wind tunnel were increased by a factor of 10.
In actual subsonic flight, airfoils with low Reynolds number flows are laminar and those with high Reynolds number flows are mostly turbulent, keeping in mind that the Reynolds number is the ratio between density, velocity, diameter, and viscosity (For an airfoil in flight rather than in a wind tunnel, D would be the distance between the leading and trailing edge called the chord length along a flow.)
02-02-2006, 10:24 PM
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RE: Ideal 3D wing loading?
The biggest plane I own, Ultra Stick Lite, is number 5 on the list. It's a great flyer with the light wing loading.Thanks
Barry
02-02-2006, 10:31 PM
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RE: Ideal 3D wing loading?
As I look at the list a couple of things kinda stand out.Look at the Harrier, one of the heaviest wing loading and yet it "feels" like a UCD. I would've thought it would have been at the top of the list.
The Funtana. It's got one of the lighter loadings of the bigger planes. As so many have said before, this plane is just misnamed. It should be a 120 size and it should have a minimum of 150, 180 or OS160 engine. I'm seriously considering taking another look at that airplane (I know!?!@?!?)
Thanks
Barry
02-02-2006, 11:26 PM
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RE: Ideal 3D wing loading?
H9 Edge=36.66 oz wingloading. It 3d's, does most of everything, but it flies HEAVY and wingrocks/tipstalls if you are not careful. It is not as easy to fly it as smooth as a light plane, but if you get used to it it's ok.
I agree that you have to take size into consideration; A 41lb 42% SuperXtra, not sure of the wing area though, it flys like it was 5 lbs and has absolutely no bad habits. I would say that each plane would have an ideal wing loading; an airplane that's lighter will do mostly everything better, while a heavy one will have it's own good points, though not many.
I agree that you have to take size into consideration; A 41lb 42% SuperXtra, not sure of the wing area though, it flys like it was 5 lbs and has absolutely no bad habits. I would say that each plane would have an ideal wing loading; an airplane that's lighter will do mostly everything better, while a heavy one will have it's own good points, though not many.
02-03-2006, 05:42 AM
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RE: Ideal 3D wing loading?
There is a different way to figure wingloading so that, no matter the difference in size, a comparison can be made, but I forget the formula. I have been flying for some time and I have come to the conclusion that, for aerobatics:
a 60 size aircraft should have a 16-17 oz loading
90 size, a 18-20
120 size, 21-22
50cc size, 23-26
100cc size, 26-30 and
150cc size, a 30-36 ounce loading.
This is just personal preference. There are people out there flying bricks, like some of the 1.60 size planes with DA 50's in them, at a 30 ounce wingloading and they like them just fine, but for me, I can tell just by watching a plane fly if it has too high a wingloading for my liking.
a 60 size aircraft should have a 16-17 oz loading
90 size, a 18-20
120 size, 21-22
50cc size, 23-26
100cc size, 26-30 and
150cc size, a 30-36 ounce loading.
This is just personal preference. There are people out there flying bricks, like some of the 1.60 size planes with DA 50's in them, at a 30 ounce wingloading and they like them just fine, but for me, I can tell just by watching a plane fly if it has too high a wingloading for my liking.
02-03-2006, 09:07 AM
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RE: Ideal 3D wing loading?
This is a question that you can answer yourself with some effort and fun along the way. Take a plane that has light loading and flies like you like, and fly it noting how it does a few maneuvers like spins. Land, add 1/2 lb of ballast at the cg and check to assure that the cg is unchanged. Fly same routine and note results. Repeat, continuing to incrementally increase the weight until performance falls off. Then tell everyone what you find. I suspect you will like it best with zero added ballast indicating that the optimum wing loading is less than what can be built with acceptable cost and adequate strength. Good flying, acceptable cost, adequate strength are all largely matters of opinion but you can find what works for you.
02-03-2006, 09:46 AM
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RE: Ideal 3D wing loading?
ORIGINAL: Jack Hyde
I suspect you will like it best with zero added ballast indicating that the optimum wing loading is less than what can be built with acceptable cost and adequate strength. Good flying, acceptable cost, adequate strength are all largely matters of opinion but you can find what works for you.
I suspect you will like it best with zero added ballast indicating that the optimum wing loading is less than what can be built with acceptable cost and adequate strength. Good flying, acceptable cost, adequate strength are all largely matters of opinion but you can find what works for you.
There is a reason the competitive pattern guys spend a lot of $ taking a few oz out of a plane. If you take a plane that is a bit heavy with bad habits and you start removing the weight you will see those bad habits start to disappear as the weight is removed. I do the opposite of this on the sim for practice -- adding fuse weight to make the plane more challenging to fly.
Flying these newer 1/4 scale IMAA legal airframes is such a different world from the ones available just a few years ago. A 12.5 pound 1000sqin scale plane used to be considered a good flying plane. When I first got a hold of a 68" E.F. Yak I could not believe the difference (8.8pounds 920sqin).[X(] It used to be that if you wanted something that was scale and flew well the only real choice was to move into a larger plane.
One negative I can think of associated with lighter weight is that the lighter the weight in relation to the exposed area in the wind direction, the more unclean, swirly, gusty air will be able to accelerate the plane away from the desired path. A constant wind makes no difference, but air unclean, swirly, gust air will move a lighter plane more than a heavy plane.
02-03-2006, 09:57 AM
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RE: Ideal 3D wing loading?
ORIGINAL: Barry Cazier
The Funtana. It's got one of the lighter loadings of the bigger planes. As so many have said before, this plane is just misnamed. It should be a 120 size and it should have a minimum of 150, 180 or OS160 engine. I'm seriously considering taking another look at that airplane (I know!?!@?!?)
Thanks
Barry
The Funtana. It's got one of the lighter loadings of the bigger planes. As so many have said before, this plane is just misnamed. It should be a 120 size and it should have a minimum of 150, 180 or OS160 engine. I'm seriously considering taking another look at that airplane (I know!?!@?!?)
Thanks
Barry
When I first started flying mine I thought it was OK. Then I started flying it like I didn't like it. The more I flew it like I didn't like it the more I started to like it. [&:] Now I like it, but still fly it like I don't.
It is a lot of fun to fly and I don't mind flying it closer to my limits when I am not all with it & the weather is crummy. [&:] [8D]
02-03-2006, 09:10 PM
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RE: Ideal 3D wing loading?
ORIGINAL: STG
If you are looking for a plane that you don't mind flying aggressively the F90 is a real value @$209 available @ your LHS. Set it up with a more forward CG, metal gear servos and adequate power (OS160fx or similar) and it flies very well. [sm=thumbup.gif] [sm=lol.gif]
When I first started flying mine I thought it was OK. Then I started flying it like I didn't like it. The more I flew it like I didn't like it the more I started to like it. [&:] Now I like it, but still fly it like I don't. It is a lot of fun to fly and I don't mind flying it closer to my limits when I am not all with it & the weather is crummy. [&:] [8D]
ORIGINAL: Barry Cazier
The Funtana. It's got one of the lighter loadings of the bigger planes. As so many have said before, this plane is just misnamed. It should be a 120 size and it should have a minimum of 150, 180 or OS160 engine. I'm seriously considering taking another look at that airplane (I know!?!@?!?)
Thanks
Barry
The Funtana. It's got one of the lighter loadings of the bigger planes. As so many have said before, this plane is just misnamed. It should be a 120 size and it should have a minimum of 150, 180 or OS160 engine. I'm seriously considering taking another look at that airplane (I know!?!@?!?)
Thanks
Barry
When I first started flying mine I thought it was OK. Then I started flying it like I didn't like it. The more I flew it like I didn't like it the more I started to like it. [&:] Now I like it, but still fly it like I don't.
It is a lot of fun to fly and I don't mind flying it closer to my limits when I am not all with it & the weather is crummy. [&:] [8D]
STG...We have this in common. I flew my Funtana like I didn't like it also. Trouble is I didn't dislike it enough to start liking it.
I've got a couple planes in the mill right now. As soon as I get one done I'm gonna order a Funtana and put a OS160 on it or maybe a YS 140. Depends on my mood. I think either engine will solve the balance issue and I'll also consider moving the rudder servo to pull/pull.
I'd really like to give it another shot.
This wing loading thing hurts my mind. After reading your epistle on the Reynolds I hurt. But I do think I favor the light wing loading. In fact all of the planes I named above have light wing loading. Some just more than others. I think it comes from living in an area that the air is so thin you can't see it. Gotta make em' light here or they won't fly.
Thanks
Barry
02-03-2006, 09:50 PM
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RE: Ideal 3D wing loading?
ORIGINAL: Barry Cazier
STG...
We have this in common. I flew my Funtana like I didn't like it also. Trouble is I didn't dislike it enough to start liking it.
I've got a couple planes in the mill right now. As soon as I get one done I'm gonna order a Funtana and put a OS160 on it or maybe a YS 140. Depends on my mood. I think either engine will solve the balance issue and I'll also consider moving the rudder servo to pull/pull.
Thanks
Barry
STG...We have this in common. I flew my Funtana like I didn't like it also. Trouble is I didn't dislike it enough to start liking it.
I've got a couple planes in the mill right now. As soon as I get one done I'm gonna order a Funtana and put a OS160 on it or maybe a YS 140. Depends on my mood. I think either engine will solve the balance issue and I'll also consider moving the rudder servo to pull/pull.
Thanks
Barry
02-03-2006, 11:11 PM
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RE: Ideal 3D wing loading?
Wing Loading is only proportional to scale or really the same design. You are comparing a quantity of (Weight)/(lenth^2) . Weight is equal to (length^3) because of density. The numerator will increase much faster than the denomonator when scale is increased.
I also say design because The EF yak also has a flying tail and a wider fuse than the UCD 60. If you ever took a class on aerodynamics you will also see that the Lift/Drag Ratio of a tapered wing is greater than a rectangular wing. I have that equation if anyone wants to see that.
Comparing the airplanes Wing loading is only a good back of the envelope calculation, nothing more. In aerospace a lot of equations are made based upon asumptions, rounding/estimating and excluding smaller terms from equations just so we can solve them.
I also say design because The EF yak also has a flying tail and a wider fuse than the UCD 60. If you ever took a class on aerodynamics you will also see that the Lift/Drag Ratio of a tapered wing is greater than a rectangular wing. I have that equation if anyone wants to see that.
Comparing the airplanes Wing loading is only a good back of the envelope calculation, nothing more. In aerospace a lot of equations are made based upon asumptions, rounding/estimating and excluding smaller terms from equations just so we can solve them.
02-04-2006, 09:37 AM
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RE: Ideal 3D wing loading?
It looks to me that Barry's question was something like does a plane with light wing loading spin "better" than the same plane with less wing loading. I still think if you select a plane that spins well as is , then ballast it up enough to make a difference it will get better, worse, or not change much. Question answered. I would be interested in the answer. I am not good enough to take the pilot out of the test but someone that is really good at spins should do well as a test pilot.
