Author Topic: wing location (Read 4010 times)

bob whitney · « **on:** December 03, 2012, 09:18:14 AM »

when building an e-ship seeing as there is no cyl hanging up or down ,would it be better to move the wing closer to the center line of the fuse.??

bob whitney · « **Reply #1 on:** December 03, 2012, 09:37:19 AM »

sorry, that should be thrust line

John Miller · « **Reply #2 on:** December 03, 2012, 12:19:29 PM »

Hi Bob,

Many designers like to have everything on the thrust line. Lou Wolgasts "Pentastar" being a recent example. I 've been told that such designs are better at having equal turning rates. Personally, I've only flown a couple of designs set up this way, so my experience may not be typical. I didn't really see any difference in the flying.

There was a difference when it cme to building, and setting the plane up.

For an inline design, one having the engine, wing, and elevator all on the thrust line, If you believe in, and use "Corrective Geometry", You may find that it takes large angular offsets to achieve equal throws.

The thrustline offset, may wind up inconseqential, and most useful with being able to use larger dia. props, without having to install taller main gear.

The often seen seperation between the wing centerline, and the stab-elevator, serves several purposes, not the least of mwhich makes it easier to set up accurate geometry between the flaps, and the elevator.

Based on these two findings, I tend away from complete in-line desgns myself.

Howard Rush · « **Reply #3 on:** December 03, 2012, 05:29:01 PM »

Quote from: bob whitney on December 03, 2012, 09:18:14 AM

when building an e-ship seeing as there is no cyl hanging up or down ,would it be better to move the wing closer to the [thrust line].??

The prop is still long, so a higher thrust line enables shorter landing gear. A difference I observed between how a good Impact and a good in-line Yatsenko Shark handled was on takeoff and landing. There might be some prop-rotation reason for having a high thrust line, but a backwards-from-usual prop works OK with a high thrust line and right thrust. Some of us noticed a peculiar need to put the CG on an electric plane higher than on an IC-powered plane. Having a high motor would help get it there.

Edit: John already said most of this above.

Howard Rush · « **Reply #4 on:** December 03, 2012, 05:48:26 PM »

Quote from: John Miller on December 03, 2012, 12:19:29 PM

The often seen seperation between the wing centerline, and the stab-elevator, serves several purposes, not the least of mwhich makes it easier to set up accurate geometry between the flaps, and the elevator.

Assuming you mean control linkage, I'd think that would be the least of which. Just do the 3D calculation.

phil c · « **Reply #5 on:** December 29, 2012, 08:08:26 PM »

I'd take a cue from the RC Pattern guys and the plethora of conventional stunters. From the talk I've heard raising the thrustline, stab, and balancing the profile area of the fuselage and fin all contribute to making the plane less sensitive to yaw/roll coupling in maneuvers. It is less sensitive to gusts for the same reason. Go too far and you also have problems. RC guys complain that full size designs like the CAP20 series(which have a low, flat wing, and a high stab) require lots of down elevator in knife edge flight. They can mix it in, but we have to do it by hand.

For the record, combat planes, with no side area to speak of and an inline design will wiggle a lot at lower speeds. They depend on lots of line pull and speed to keep the plane straight on the line. They have nothing to damp yaw from prop precession or wind gusts, no side area to help with flying high, and the tail tends to end up in the wing wash in tight maneuvers, if it isn't far enough from the wing.

Igor Burger · « **Reply #6 on:** December 30, 2012, 02:16:58 AM »

Proper question in this moment would be what is that "thrust line" of prop permanently yawing left and thus making precession and entering air little bit sidewise and thus making Pforce.

.... and then we can start to think if to put the wing to thrust line, or counter ballance the landing gears drag :- )))

Chuck_Smith · « **Reply #7 on:** December 30, 2012, 04:37:09 AM »

There are good reasons to have the stab offset from the wing.

The wing has a turbulent wake and you want the stab/elevator out of it for good tracking in level flight. As mentioned earlier the control geometry work better too.

Stunt planes are mostly fixed-gear and the landing gear drag produces a non-trival nose-down moment. When you think about it, the best planform may be to put the wing lightly above the thrust line and the tail slightly below. But that looks weird.

Howard Rush · « **Reply #8 on:** December 30, 2012, 07:12:03 PM »

Quote from: Chuck_Smith on December 30, 2012, 04:37:09 AM

Stunt planes are mostly fixed-gear and the landing gear drag produces a non-trival nose-down moment.

Show us.

Chuck_Smith · « **Reply #9 on:** December 31, 2012, 06:10:16 AM »

Quote from: Howard Rush on December 30, 2012, 07:12:03 PM

Show us.

Well Howard, let's take a look-see.

For aircraft design the historical D over q for a wheel in a streamlined fairing is 0.13. D over q has units of ft^2 ...although we usually divide buy the reference area and express it as a coefficient.

So lets say a faired wheel has a frontal area of 2.5 in^2, dividing by 144 we get 1.736E-2 ft^2.

The CD for each wheel is then (1.736E-2ft^2 x 0.13)/3.72ft^2 = 6.07E-4 (where 3.72 ft^2 is the reference area - $ - for a Brodack Vector 40 we used in the turn radius analysis...turns out it won't have an effect on the outcome but I wanted to put the CD in coefficient form.)

Next, since we are astute aircraft designers we add 20 percent for interference factors between the struts and fairings...7.28E-4 is the Drag Coefficient we use.

We know the drag is calculated as 1/2 x rho x V^2 x $ x CD <- you see here the reference area isn't really required to compute the drag. We divided by it and later multiplied by it.

Using .2308E-2 slugs/ft^3 for rho, and 79 ft/sec for V we plug and chug to get the drag per wheel.

(.5)(.002308)(79^2)(3.72)(.000728) = 3.90E-2 lbs drag per wheel. If you do the dimensional analysis you see we end up with slugs x ft/ sec^2, so that's a good check. Now multiplying by two and then by 16 to get ounces we end up with 1.25 oz drag from the wheels.

Let's say the wheels are 6 inches from the vertical CG, that's roughly 7.5 inch-ounces of moment.

And I should note, an unfaired wheel will have about twice the drag of a well faired one, so make that 15 inch-oz for unfaired wheels.

And actually, to simplify things we left the drag from the struts out and they too make a contribution. I'm too lazy to integrate over their length today. Interestingly, round wire gear have substantially less drag than aluminum fuse-mounted do.

Also, the wheel drag isn't constant. It decreases on inside turns and increases on outside turns due to the wing's flow field effects. Betcha didn't see that one coming!

Chuck

Serge_Krauss · « **Reply #10 on:** December 31, 2012, 11:51:37 AM »

Isn't rho .002378 in those units?

Chuck_Smith · « **Reply #11 on:** December 31, 2012, 12:17:39 PM »

Serge,

I always figure about 1000ft density altitude when I do calcs like this.

Chuck

Igor Burger · « **Reply #12 on:** December 31, 2012, 01:28:18 PM »

strange, I did not know that heavier wheels will pith down less than lighter

Howard Rush · « **Reply #13 on:** December 31, 2012, 04:23:57 PM »

Actual effort. Unusual for these conversations. Good for you, Chuck. I did a retract drag energy calculation awhile back, so I appended the moment calculation to it. It's on the attached spreadsheet. Inputs are the yellow cells. I started with a wheel Cd from Hoerner's book: .15 for unfaired wheels, pretty close to what Chuck used. I didn't check to see if the reference areas we used were the same. Anyhow, I got a lot less wheel moment (Chuck must have substandard fairings), but when I included wire strut drag, I got about the same number: 7 in.oz. The initial assertion that Chuck was asked to defend was that landing gear moment is nontrivial. I calculate a stab Cl increment of .002, nontrivial for Chuck, but I don't think a duffer like me could feel it.

Quote from: Chuck_Smith on December 31, 2012, 06:10:16 AM

Also, the wheel drag isn't constant. It decreases on inside turns and increases on outside turns due to the wing's flow field effects. Betcha didn't see that one coming!

I have been hearing a noise during maneuvers on my electric stunter that I didn't hear on the IC-powered stunter. I was thinking that it was prop noise, but now I see that it's the wheels rotating. Thanks, Chuck.

Chuck_Smith · « **Reply #14 on:** December 31, 2012, 08:33:23 PM »

Quote from: Howard Rush on December 31, 2012, 04:23:57 PM

Actual effort. Unusual for these conversations. Good for you, Chuck. I did a retract drag energy calculation awhile back, so I appended the moment calculation to it. It's on the attached spreadsheet. Inputs are the yellow cells. I started with a wheel Cd from Hoerner's book: .15 for unfaired wheels, pretty close to what Chuck used. I didn't check to see if the reference areas we used were the same. Anyhow, I got a lot less wheel moment (Chuck must have substandard fairings), but when I included wire strut drag, I got about the same number: 7 in.oz. The initial assertion that Chuck was asked to defend was that landing gear moment is nontrivial. I calculate a stab Cl increment of .002, nontrivial for Chuck, but I don't think a duffer like me could feel it.

I have been hearing a noise during maneuvers on my electric stunter that I didn't hear on the IC-powered stunter. I was thinking that it was prop noise, but now I see that it's the wheels rotating. Thanks, Chuck.

Howard, cool spreadsheet. Is the 2/3 multiplier on the moment an approximation of the integrated moment?

One thing I didn't see is the tail efficiency. If I'm reading the sheet - and I admit my inspection was cursory - you are assuming 100 percent efficieny from the tail. I'd be tempted to put in a constant for efficiency. Our tails can be more than 100 percent efficient because our ships are "draggy" so we have a substantial slipstream from the propeller.

Another thing, some of the stunt superlong wheel pants are even more inefficient due to the extreme wetted area.

Howard Rush · « **Reply #15 on:** December 31, 2012, 10:32:53 PM »

Quote from: Chuck_Smith on December 31, 2012, 08:33:23 PM

Is the 2/3 multiplier on the moment an approximation of the integrated moment?

I didn't give it much thought. I figured that the integral of a ramp was the area of the triangle under it (actually one triangle minus another).

Quote from: Chuck_Smith on December 31, 2012, 08:33:23 PM

Our tails can be more than 100 percent efficient because our ships are "draggy" so we have a substantial slipstream from the propeller.

I wouldn't notice a factor of three.

That reminds me of when a guy let me fly his canard pusher. He advised me not to give it any control input until well after it took off.

Quote from: Chuck_Smith on December 31, 2012, 08:33:23 PM

Another thing, some of the stunt superlong wheel pants are even more inefficient due to the extreme wetted area.

Who among us has ever sacrificed coolness for drag reduction?

Chuck_Smith · « **Reply #16 on:** January 02, 2013, 10:17:48 AM »

Quote from: Howard Rush on December 31, 2012, 10:32:53 PM

I wouldn't notice a factor of three.

Well now wait a minute...we're talking about the contribution to the total moment.

Since the moment coefficient for the a typical uncambered section is on the order of 10E-5, I submit that the wheels are a major (perhaps THE major) contributor to the total moment.
I call that non-trivial. You can now also see why I go to the trouble of dividing by the reference area to put the LG drag in coefficient form. There really is a method to the madness sometimes.

Quote from: Howard Rush on December 31, 2012, 10:32:53 PM

Who among us has ever sacrificed coolness for drag reduction?

Boeing.. when they changed from JT8D's on the 737s to the CFM56's. That raised nacelle looks terrible. Granted they did need to raise it some for clearance, but then they found the flow problem and raised it even higher to it's now awkward and wrong position. Although... when the light hits them just right if you squint you can almost see an R2800, so I guess they are cool afterall.

Igor Burger · « **Reply #17 on:** January 02, 2013, 02:18:42 PM »

Quote from: Chuck_Smith on January 02, 2013, 10:17:48 AM

Since the moment coefficient for the a typical uncambered section is on the order of 10E-5, I submit that the wheels are a major (perhaps THE major) contributor to the total moment.

And since we have negative AoA on tail, I would say it is "somehow different" :- ))))

Howard Rush · « **Reply #18 on:** January 02, 2013, 02:20:46 PM »

These are jokes--right? As I said, Chuck, gear drag moment a delta Cl of .002 on the stab, referenced to stab area. That's what, .1 degree of elevator? Given a stunt plane with no particular extra effort built into it to counter the massive negative pitching moment of my unfaired wheels and flat-slab struts, I can still do actual triangular loops. I've gotten as many as 20 points for each for them.

Given the three-thousand-airplane production backlog for 737s, I am sure that your identifying the correct engine position would be worth millions of dollars. For a mere 10% of that (up front), I'll introduce you to the pertinent players.

Igor Burger · « **Reply #19 on:** January 02, 2013, 02:26:37 PM »

And BTW ... I see numbers for 4 decimal places, but you calculate that moment to the CG? I already asked, but somehow not answered, does it mean that heavier wheels makes moment of gears lower? (heavier wheel will make arm gear to CG shorter so by the calculation above, the moment must be clearly smaller)

It should be either to some "vertical neutral point" ... or it should be done correctly, means all moments and forces recalculated to ONE (ANY - CG, AC, nose, rudder tip) point with and without LG ... and the difference will show effect of LG.

Igor Burger · « **Reply #20 on:** January 02, 2013, 02:29:52 PM »

Quote from: Howard Rush on January 02, 2013, 02:20:46 PM

These are jokes--right? As I said, Chuck, gear drag moment a delta Cl of .002 on the stab, referenced to stab area. That's what, .1 degree of elevator?

may be, but we have it in real to just opposite direction. That .1 deg AoA compensating LG drag must be NEGATIVE AoA, while we need POSITIVE AoA on tail to have neutral model :- ))))

Chuck_Smith · « **Reply #21 on:** January 02, 2013, 02:56:15 PM »

Quote from: Howard Rush on January 02, 2013, 02:20:46 PM

These are jokes--right? As I said, Chuck, gear drag moment a delta Cl of .002 on the stab, referenced to stab area. That's what, .1 degree of elevator? Given a stunt plane with no particular extra effort built into it to counter the massive negative pitching moment of my unfaired wheels and flat-slab struts, I can still do actual triangular loops. I've gotten as many as 20 points for each for them.

Given the three-thousand-airplane production backlog for 737s, I am sure that your identifying the correct engine position would be worth millions of dollars. For a mere 10% of that (up front), I'll introduce you to the pertinent players.

Howard, I think you misread my intention. I'm fully aware of the CFD flow results that showed where to locate the diffuser intakes on the 737. I was just saying that that's an example of giving up coolness for drag reduction. The 737 is probably the best all-around airplane ever produced, and Boeing makes the best transports in the world, bar none. I apologize if I didn't make my point clearly enough.

As far as the deflection, I agree it isn't much, but it may still be one of major contributors to the location of the nuetral point. All the values are pretty darned small, but all contribute to the static margin, and that's what equates to "feel" for the pilot. You my not be able to feel the stick force for .1 degrees, but that moment may still change the handling. And as noted earlier, it's dynamic and a function of the AoA and flap angle.

Then again, maybe we can't feel it. I think we need to build a testbed with retracts!

Chuck

Howard Rush · « **Reply #22 on:** January 02, 2013, 03:09:54 PM »

Quote from: Igor Burger on January 02, 2013, 02:26:37 PM

And BTW ... I see numbers for 4 decimal places, but you calculate that moment to the CG? I already asked, but somehow not answered, does it mean that heavier wheels makes moment of gears lower? (heavier wheel will make arm gear to CG shorter so by the calculation above, the moment must be clearly smaller)

It should be either to some "vertical neutral point" ... or it should be done correctly, means all moments and forces recalculated to ONE (ANY - CG, AC, nose, rudder tip) point with and without LG ... and the difference will show effect of LG.

I was wondering what you meant by that. You are correct, of course.

Quote from: Igor Burger on January 02, 2013, 02:29:52 PM

may be, but we have it in real to just opposite direction. That .1 deg AoA compensating LG drag must be NEGATIVE AoA, while we need POSITIVE AoA on tail to have neutral model :- ))))

Correct again, even after I put calculations in obscure American units to make it difficult for Igor to interfere.

Howard Rush · « **Reply #23 on:** January 02, 2013, 03:41:34 PM »

Quote from: Chuck_Smith on January 02, 2013, 02:56:15 PM

As far as the deflection, I agree it isn't much, but it may still be one of major contributors to the location of the nuetral point.

Thanks for another revelation, Chuck. Instead of adding ballast to my airplanes nose, I could have just used bigger wheels-- or is it smaller wheels?

Brett Buck · « **Reply #24 on:** January 03, 2013, 12:00:49 AM »

Quote from: Igor Burger on January 02, 2013, 02:29:52 PM

may be, but we have it in real to just opposite direction. That .1 deg AoA compensating LG drag must be NEGATIVE AoA, while we need POSITIVE AoA on tail to have neutral model :- ))))

Say, didn't I see some long tedious analysis of that somewhere? I trump the piddling 7 in-oz of "nose down" from LG drag (which, by the way, is in the ballpark of what I got for a wheel +*faired* gear wire - it's more for unfaired wire), with 33 in-oz* of "nose up" from the precession of constantly yawing to the left.

Another item of more interest is that the torque from the thrust line missing the CG (vertically) is also impressive, even more when you put in downthrust. And it varies *wildly* in flight since the thrust is all over the place. Figure the thrust line misses the CG by an inch, the level flight thrust is about a pound and a half or so, so 24 inch-ounces, nose-down, in level flight and maybe half again more as the speed drops in corners.

Brett

*SN Design Column, Jan 06

Chuck_Smith · « **Reply #25 on:** January 03, 2013, 04:49:34 AM »

Brett,

You are correct, I only made the statement that the LG moment is "non-trivial" If the thrust moment is the 24 in-oz, and the LG are 30% of that, I contend they are a non-trivial contribution to the airplane's total pitching moment.

Plus, due to the flow field effects the neutral point of the airplane moves from inside to outside maneuvers, i.e., the landing gear cause non-linearity in the dCm/dAoA function. So you will have better turn tracking one way than the other. Anybody care to guess which way? Granted, it will be a small effect, but it is real.

Chuck

Howard Rush · « **Reply #26 on:** January 03, 2013, 12:22:50 PM »

Quote from: Chuck_Smith on January 03, 2013, 04:49:34 AM

Brett,

You are correct, I only made the statement that the LG moment is "non-trivial" If the thrust moment is the 24 in-oz, and the LG are 30% of that, I contend they are a non-trivial contribution to the airplane's total pitching moment.

Plus, due to the flow field effects the neutral point of the airplane moves from inside to outside maneuvers, i.e., the landing gear cause non-linearity in the dCm/dAoA function. So you will have better turn tracking one way than the other. Anybody care to guess which way? Granted, it will be a small effect, but it is real.

Chuck

You must have read one of those books that refer to moments as stabilizing or destabilizing.

Brett Buck · « **Reply #27 on:** January 03, 2013, 03:15:06 PM »

Quote from: Chuck_Smith on January 03, 2013, 04:49:34 AM

Brett,

You are correct, I only made the statement that the LG moment is "non-trivial" If the thrust moment is the 24 in-oz, and the LG are 30% of that, I contend they are a non-trivial contribution to the airplane's total pitching moment.

Plus, due to the flow field effects the neutral point of the airplane moves from inside to outside maneuvers, i.e., the landing gear cause non-linearity in the dCm/dAoA function. So you will have better turn tracking one way than the other. Anybody care to guess which way? Granted, it will be a small effect, but it is real.

Neutral point seems to mean something different that what I understand. I think the effect is a bias more than a change in the stability.

Brett

Chuck_Smith · « **Reply #28 on:** January 05, 2013, 05:35:50 AM »

Quote from: Howard Rush on January 03, 2013, 12:22:50 PM

You must have read one of those books that refer to moments as stabilizing or destabilizing.

Howard, to me a moment is a moment is a moment, and is only a contribution to a total moment so it can't be stabilizing or destabilizing. The derivative of the the moment WRT AoA on the other hand, has everything to do with stability.

Like I always say you can have static stability but not dynamic stability. People love to talk about static stability...summing the moments and making everything zero. It's easy to create the free-body-diagram. I did it above to find the LG's contribution to the total moment. Static stability is really more theoretical than practical though.

What is dynamic stability? It's the airplane's tendency to return to it's desired condition after it encounters something that disturbs it from the desired plight path. And for this to happen, dCm/dAoA must be negative.

What I was saying in my previous post is that these derivatives are not constants. For example:

Brett points out that for a fix pitch prop the thrust is function of airspeed at a given RPM. Well that means if we are running a constant RPM setup, the thrust contribution to the total moment is a function of airspeed.

I've explained how the drag due to the wheels isn't constant.

So what? It's pretty nuanced and nerdy. But since CL planes fly in turbulence for a living it's worth at least thinking about. It's really the reason why some CL planes are groovy and point well and others are wallowing or hunting. Everyone wants to move the CG forward when their plane doesn't track well. That will work - but at the cost of maneuverability.

Howard Rush · « **Reply #29 on:** January 05, 2013, 04:29:27 PM »

If you are considering dCl/dalpha of the landing gear, you are really, really getting into insignificance.

FLOYD CARTER · « **Reply #30 on:** January 05, 2013, 04:52:02 PM »

Before this thread went South into LaPlace Transforms, the topic was wing location. (Remember?)

My newest e-stunter (still in construction) has a high thrust line (for a 13" prop) and also a high wing location on the fuselage. So....in order to get those leadouts down in the right place, I'm using Anhedral! 1" down on each wingtip,.

That demands a "jet-like" style, even though I don't like jet planes.

(One must suffer in order to achieve greatness).

Floyd

Howard Rush · « **Reply #31 on:** January 05, 2013, 05:25:53 PM »

You could have a high battery location, too, and keep the wing straight. If you do, you should keep the wing centered on the fuselage, lest you have Cl_beta. A way to do this with short gear is to have a separate takeoff motor with a wee prop. You could have the first stunt plane on the cover of Low Rider.

Chuck_Smith · « **Reply #32 on:** January 05, 2013, 06:22:02 PM »

Quote from: Howard Rush on January 05, 2013, 05:25:53 PM

You could have a high battery location, too, and keep the wing straight. If you do, you should keep the wing centered on the fuselage, lest you have Cl_beta. A way to do this with short gear is to have a separate takeoff motor with a wee prop. You could have the first stunt plane on the cover of Low Rider.

Well, e-power with timers makes JATO a viable option fro CLPA too! I can see stunt getting a lot more exciting!

FLOYD CARTER · « **Reply #33 on:** March 28, 2013, 11:26:16 AM »

Wing Location. The wing had to be mounted high in order to fit the battery at the CG. In order to get the leadouts close to the plane's center of mass, the wing has anhedral.

59" span. AXI motor

The name of the plane is "32"
Floyd

Mark Scarborough · « **Reply #34 on:** March 28, 2013, 11:32:01 AM »

Quote from: FLOYD CARTER on January 05, 2013, 04:52:02 PM

Before this thread went South into LaPlace Transforms, the topic was wing location. (Remember?)

My newest e-stunter (still in construction) has a high thrust line (for a 13" prop) and also a high wing location on the fuselage. So....in order to get those leadouts down in the right place, I'm using Anhedral! 1" down on each wingtip,.

That demands a "jet-like" style, even though I don't like jet planes.

(One must suffer in order to achieve greatness).

Floyd

Same Idea I used in my Electrajet,, ( may she rest in peices)

Tim Wescott · « **Reply #35 on:** March 28, 2013, 01:13:00 PM »

Quote from: FLOYD CARTER on March 28, 2013, 11:26:16 AM

Wing Location. The wing had to be mounted high in order to fit the battery at the CG. In order to get the leadouts close to the plane's center of mass, the wing has anhedral.

59" span. AXI motor

The name of the plane is "32"
Floyd

Should be able to do the same thing with a low wing and dihedral? No?

RandySmith · « **Reply #36 on:** March 28, 2013, 02:10:44 PM »

"Then again, maybe we can't feel it. I think we need to build a testbed with retracts!

Chuck"

Hi Chuck
Don't need to even do that, I have flown the same plane , very well trimmed with the LG on, then flew it with the LG off, It was very different, and the outside turn was much reduced, making the plane very hard to fly without retrim, Even removing the wheel pants so I could fly on grass made the turn trim way off..as far as trying to fly a precision pattern went

Randy

FLOYD CARTER · « **Reply #37 on:** March 28, 2013, 03:11:06 PM »

[
Don't need to even do that, I have flown the same plane , very well trimmed with the LG on, then flew it with the LG off, It was very different, and the outside turn was much reduced, making the plane very hard to fly without retrim, Even removing the wheel pants so I could fly on grass made the turn trim way off..as far as trying to fly a precision pattern went

Randy
[/quote]

This is true, and quite significant. I have an RSM P-51 fitted with retract landing gear. When the wheels go up, the plane is totally different! It takes me another lap to adjust to the change in flight trim.

F.C.

Mark Scarborough · « **Reply #38 on:** March 28, 2013, 04:09:08 PM »

Quote from: Tim Wescott on March 28, 2013, 01:13:00 PM

Should be able to do the same thing with a low wing and dihedral? No?

yeah but it will never be as cool as annhydrel

Tim Wescott · « **Reply #39 on:** March 28, 2013, 04:12:32 PM »

Quote from: Mark Scarborough on March 28, 2013, 04:09:08 PM

yeah but it will never be as cool as annhydrel

My brain was warped at an early age by a Sig Dewybird. It just looked so cool coming around the circle with that slight dihedral.

Don't be surprised by a warbird or some zippy civilian semi-scale at some point in the future (a V-tailed doctor killer looks tasty, don't you think?).