blended winglets

[steve]

i put in a cap and a spar (in the first wing/blend).

i tapered the tape as it got closer to the tip (it made no sense to put all that wight up there). i kept the cap 3" all the way up

mine is also one long run, no splice, although ilbet yours was a lot easier to cover;)

[Edge 513]

i put in a cap and a spar (in the first wing/blend).

i tapered the tape as it got closer to the tip (it made no sense to put all that weight up there). i kept the cap 3" all the way up

 

That's the ticket. Make the 3" troughs. Cut the L.E.'s off with a hot wire. Round the fronts and 2 ply BID shear web to start out with. Trough the back of the L.E. to allow the wireing for the tip lights/stobe. Drag a heavy string [or the wire] through and exit it at the top. Then 5 min epoxy the L.E.s back on [4 hands is good for this] and install the spar caps. 2 layers 3 inch wide spar tape to the top, then 2 @ 4 Inches down, 2 more at 6" down and the last 2 at 6" below that. Gives 8 layers of spar tape through the blend. Trough the rudder cable line and install the comm tapes and torriods. Micro the surfaces and then 2 plies UNI at the proper orientation to cover. MAMMA MIA!!! Thats a SPICY MEATBALL!!! No, actually thats a beautiful strong B.W. =)

 

No liability for the above is expressed or implied. Quality is totally subjective to the builders ability and consistency. YMMV.

[Marc Zeitlin]

... But the B.W. as built with the spar cap running through it is WAYYYY stronger than plans.

Says which structural engineer, with what analysis backing it up?

 

No 15 plies needed.

I don't know what 15 plies you're talking about, but there are 7 plies of skin reinforcements top and bottom that I have never recommended leaving out on any blended wing/winglet modification that I've helped on, two sets of which have flown safely.

 

I'd be interested in seeing the engineering analysis that says it's OK to leave out the reinforcing layups, or conversely, to leave in the reinforcing layups and leave out the spar/shear web.

 

Please don't make safety related recommendations when not educated on a subject. We've had more than enough of that elsewhere.

 

FWIW.

[longez360]

In support of Marc Z, I would urge those contemplating major changes to design to seek guidance from authorities on the subject matter, both structurally and aerodynamically. If not, perhaps reconsider the type of aircraft you are building.

 

I would also urge those who may not necessarily adhere to Marc's professional advice due to personality conflicts to take a step back and understand his intent.

 

You are not just risking your own life here.

 

Please take care out there, gang.

[steve]

That's the ticket. Make the 3" troughs. Cut the L.E.'s off with a hot wire. Round the fronts and 2 ply BID shear web to start out with. Trough the back of the L.E. to allow the wireing for the tip lights/stobe. Drag a heavy string [or the wire] through and exit it at the top. Then 5 min epoxy the L.E.s back on [4 hands is good for this] and install the spar caps. 2 layers 3 inch wide spar tape to the top, then 2 @ 4 Inches down, 2 more at 6" down and the last 2 at 6" below that. Gives 8 layers of spar tape through the blend. Trough the rudder cable line and install the comm tapes and torriods. Micro the surfaces and then 2 plies UNI at the proper orientation to cover. MAMMA MIA!!! Thats a SPICY MEATBALL!!! No, actually thats a beautiful strong B.W. =)

 

No liability for the above is expressed or implied. Quality is totally subjective to the builders ability and consistency. YMMV.

did you follow......i'll pm this. sorry

[mplafleur]

I don't know what 15 plies you're talking about, but there are 7 plies of skin reinforcements top and bottom that I have never recommended leaving out on any blended wing/winglet modification that I've helped on, two sets of which have flown safely.

 

I'd be interested in seeing the engineering analysis that says it's OK to leave out the reinforcing layups, or conversely, to leave in the reinforcing layups and leave out the spar/shear web.

I think Dennis may be referring to other blended winglets being built WITHOUT the spar/shear web extension and only using the 7 (or maybe 15) plies on the skin.

[Richard Schubert]

Marc wrote

Says which structural engineer, with what analysis backing it up?

I for one would be interested in your methodology for analyzing a curved composite beam.

[Edge 513]

Richard...see the analysis on a curved beam? With all due respect...Why not just build the thing and fly it to 290 mph repeatedly and call it as you see/experience it?

 

Thanks all. This IS the reason I posted, to get something out on the table. I have heard or seen photos of several BW's now. Those doing it are all across the board with this. People are wanting to do this change yet they are in the dark about it. There's box construction..modified 15 ply assemblies split between inside and outside with angles and 90 degree offsets thrown in. Theres ''skin-jobs'' where all the plies are on the surface with no internal structure. What ELSE will people come up with?? There's some scary stuff that hasn't flown yet. The iteration I have built have flown at the above speeds. That's where I am at with this. If I need another 5 plies in the roughly plans location top and bottom, no biggie. But the thing has FLOWN, as constructed, bed, bath and way beyond Cozy Vne. The thing is a continuation of THE WING.

 

I can understand and get behind Marc wanting to go on record he has nothing to do with these postngs of mine. Jack too. Agreed. In fact, I am going on record with regards to no liability regarding this as a recommendation. BUT, I figured somebody SHOULD try and shed some light on it, to help the poor bounders who are scratching their heads and going off on their own on BW's. I figure since I am no structural engineer I am the guy to cat-burp out some info...

 

So that is kinda, how I see it. Please flame me for safety's sake. It can only help out the cause.

YMMV.

[Wayne Hicks]

One sure way to know would be to load test the BW winglets statically. Do what RAF did. Hang the wing so that the winglet is horizntal and apply shot bags onto the winglet. And then stand the wing up and repeat.

 

Flying the wing configuration is one thing. But how do you apply side loads of the unanticipated kind in flight and still live to talk about it?

[Richard Schubert]

Let me rephrase that:

 

"I for one would be interested in your methodology for analyzing a curved composite beam. :D"

 

I think we need a tongue in cheek smilie.

 

Seriously though, I would like to know a little bit more about how these things are designed. As the Dear Leader says, this is an opportunity for a "teachable moment". I like to think the main reason everyone is here is to learn something. Just because the discussion might be difficult to follow doesn't mean it won't have value. I guess I am just an incurable technical geek.

 

I think it is great that you and Jack have flight tested this modification. Your success is what has inspired others to follow. After all, the wisest man learns from the successes of others.

[Edge 513]

One sure way to know would be to load test the BW winglets statically. Do what RAF did. Hang the wing so that the winglet is horizntal and apply shot bags onto the winglet. And then stand the wing up and repeat.

 

 

Jack wants to do exactly that to the surviving blended winglet from his ERacer Extreem. Anybody care to contribute a finished plans built winglet for the comparison? Yea, that's the problem.

When one grabs onto a plans winglet and starts pulling on it tenetively at first, then more robustly, it feels more flexy than the BW with it current plies/construction hanging in my garage. All the force seems to concentrate down in that 90 degree transition. Not a problem. The plans Vert stabilizer/winglet is proven. This is just to say that the Area51 BW feels stronger.

And Richard, you're the best, no offense intended. It should be noted that Jack has flown and tuft tested them, I have simply wanted to follow HIS success.

I'll sign off now.

[steve]

Just to post a couple of pics of Jack's and my work on my wings over last weekend to show the spar cap assemblies since many are wondering about the blended cores structure. Veru easy to accomplish and is now ready to cut out the rudders.

Yes, I am not just "winging" it...but am working with the brightest in our community. Looking at a "system" using oversize wet strake leading edges, longer original canard etc to fulfill my 540 powered Cozy with regards to Cg and performance across the board.

Thanks, Marc, Jack, Chris, Lynn for all your help and input.

i see the LE is even, stab and wing that is, and when i did mine there was no way it could be done. one would need to draw a line from wing le(side view) to the tip of the stab Le, them copy that angel. 62.5 iirc.

you just showed me a pic of a flying BW and i saw a convexed LE right at the blend (it is what i would expect if one did not alter the stab but left it stock).

so, did you make a new airfoil temp for cutting the big end of your stab ?

it looks factory ? even i cant read this...i will dodal it, tap,tap, here you are

[Edge 513]

Steve,

You set up the Vert Stabilizer winglet foam blank on top of the 8" block so that it sights -in line up- with the sightline of the long line of the front wing LE. Then you sand off the front of the 8" block so that the winglet LE and the wing LE meet. First though, the plans vert stabilizer winglet is reduced in size by cutting off the lower 4 to 6 inches. I did 5 I think. The BW airfoil isnt worked on till the front reference LE is done. See the past pic I posted. The 8x8 block is then hand contoured to the airfoil shape. You can run a hotwire saw through the middle of the blend a couple of times to section it, and check to see if your airfoil is shaping up correctly., but you are achieving a subtle blend in airfoil shape transition going from the wing airfoil form into the winglet airfoil form. Use 5min epoxy to reattach your BW together. I dont see how a template for hot wiring this complex shape could be made as it changes so dynamically. The TE swoops through what is left over in the transition from the cantilevered winglet TE and the wing LE.

As Wayne is fond of saying..Clear as mud, right?

 

BTW, As Marc has pointed out on his website and preliminary analysis, it appears Chris E's Cozy gained NO performance increase in speed from doing BW's on his wings. Chris' winglets/BW's are set back...not like these, where the LE's match. I am also not sure of his radius. His also tilt outward over 10 degrees. If one tilts their winglets outward, it will contribute some bank into yaw when using a rudder. I left my Vert stabilizers vertical. Not sure if any of that affects Chris' speed performance, especially his TE not lining up.

[Marc Zeitlin]

... the plans vert stabilizer winglet is reduced in size by cutting off the lower 4 to 6 inches. I did 5 I think... Chris E's Cozy gained NO performance increase... I am also not sure of his radius...

I find it interesting that apparently no one has actually attempted to make the radius what I recommended, and I'd venture a guess that the 4" - 5" that you've got will end up being way too small, as I've said before. Especially near the TE. Possibly better than Chris' (possibly, due to no LE offset), but not as much improvement as Jack's.

 

Note the TE shape of the CRJ 700 wing/winglet intersection - offset LE's; almost no LE radius, with a LARGE radius at the TE and a TE extension:

 

http://www.flickr.com/photos/emilywhiting/419754727/

 

Positive pressure gradients, or very slightly negative - that's what this is all about.

[TMann]

.... so, with a leading edge that is not offset (like Jack's) and a 12 inch radius, if the shape of the airfoil remains true through the radius, is that what you're after?

 

I've also heard some concerns as to the height of the winglets after the mod. If the length of the winglet section was shortened to net out at the same height as a non-blended winglet, wouldn't that be the effect that you are after?

 

Granted, if you are following the large rudder plan, there would be a difference in surface area but I would not figure it to be real significant, after all it would still be much more than the original Long-EZ plans.

[Marc Zeitlin]

.... so, with a leading edge that is not offset (like Jack's) and a 12 inch radius, if the shape of the airfoil remains true through the radius, is that what you're after?

Mostly. Hard to achieve with the different chord lengths. It would probably be better to use something closer to a symmetric airfoil closer to the center of the blend to raise the trailing edge as the blend progresses from wing to winglet.

 

I've also heard some concerns as to the height of the winglets after the mod. If the length of the winglet section was shortened to net out at the same height as a non-blended winglet, wouldn't that be the effect that you are after?

Yes. It's the projected area that matters, not the straight section length.

 

Granted, if you are following the large rudder plan, there would be a difference in surface area but I would not figure it to be real significant, after all it would still be much more than the original Long-EZ plans.

From a rudder standpoint, just extend the rudder to the tip. BFD.

[Edge 513]

I find it interesting that apparently no one has actually attempted to make the radius what I recommended, and I'd venture a guess that the 4" - 5" that you've got will end up being way too small, as I've said before. Especially near the TE. Possibly better than Chris' (possibly, due to no LE offset), but not as much improvement as Jack's.

 

Note the TE shape of the CRJ 700 wing/winglet intersection - offset LE's; almost no LE radius, with a LARGE radius at the TE and a TE extension:

 

http://www.flickr.com/photos/emilywhiting/419754727/

 

Positive pressure gradients, or very slightly negative - that's what this is all about.

The 5 inches I cut off the bottom of the plans winglet was to reduce the height of the winglet/stabilizer.

My 6" center BW radius is larger than Jacks 5-3/4" Eracer Extreem BW. He wanted to do that as an improvment beyond his. I just spectatored that part.

Yes the radius' change as you move front to back to the TE. It opens to 13.5" Dia. [Dia, NOT radius]

If anything mine should perform marginally better than his.

[SAF_Zoom]

Maybe its been discuss before, but does having no bottom winglet (only a blended winglet) make the plane more susceptible to spinning when getting near the stall ?

[michaelj]

That looks incredibly good! A ten knot increase is respectable. Well worth our continued interest.

[Lynn Erickson]

Be interesting to see a 12" radius. what do the engineering numbers say that should do for us.

Jack, at what airspeed did you see an 10 knot increase.

[Jack Morrison]

It was very consistant from 140 kt and up. I chose to go with the approximate 12 inch diameter to keep the rudder down as close to the wing as possible. The larger the blend the higher the rudder and the taller the winglet would be to maintain the same rudder control. I also think it would look a bit odd a large radius of 12 in , or 24inch diameter, on such a small AC. The blend accomplished very close to what I anticipated, with no adverse handling characteristics. I was also able to eliminate the trailing edge fences I had on prior to the blended winglets. The blended winglets on Dennis Passey's Cozy are very close to the ones I had on my E Racer, a few subtle changes. I think some where down the line someone must have confused a 12 in diameter with a 12 inch radius blend.

 

Jack

[Lynn Erickson]

It was very consistant from 140 kt and up. I chose to go with the approximate 12 inch diameter to keep the rudder down as close to the wing as possible. The larger the blend the higher the rudder and the taller the winglet would be to maintain the same rudder control. I also think it would look a bit odd a large radius of 12 in , or 24inch diameter, on such a small AC. The blend accomplished very close to what I anticipated, with no adverse handling characteristics. I was also able to eliminate the trailing edge fences I had on prior to the blended winglets. The blended winglets on Dennis Passey's Cozy are very close to the ones I had on my E Racer, a few subtle changes. I think some where down the line someone must have confused a 12 in diameter with a 12 inch radius blend.

 

Jack

how do you test for an increase in speed at 140 kts? how do you know it is faster? top speed is easy but testing at half speed is difficult. also did it change landing speed and dutch roll at low speed. removing the lower winglet does make a difference. does the radius help on dutch roll over the no winglet E racer wing. this wing was also tested on an E racer with a much higher wing loading then the standard cozy IV has. we will have to wait to see it on a cozy IV before we will know the real effect.

[steve]

Steve,

You set up the Vert Stabilizer winglet foam blank on top of the 8" block so that it sights -in line up- with the sightline of the long line of the front wing LE. Then you sand off the front of the 8" block so that the winglet LE and the wing LE meet. First though, the plans vert stabilizer winglet is reduced in size by cutting off the lower 4 to 6 inches. I did 5 I think. .

all that is true, but there is something missing.

if you go back to the plans set up and tape out the top of the stab, the tip will be 4" (?) back from where you have yours now because you did away with the setback at the root. so to get a good flow on the LE you will change the angle so the stab is canted rearward more than stock. ill draw it

clear as mud right ?

i just think the winlet with the most set back will have the less drag

we will need to barow some wings to tell..lol marc?

do you think we could get marc to fly are wings on his plane ?

[TMann]

Steve ..... enough with the CAD drawings!

Sheeeeeesh .... these SolidWorks guys!

[Edge 513]

Months ago when I asked Marc if he was going to do BW's on his plane, I think he said something like to much work for to little gain. So while HIS BW's would probably have a 12" radius, I dont think you'll see them occur which is too bad, as he would do a nicejob on them.

I wouldnt rake the Vert stabilizer tip back any Steve. The rake angle is per plans. However you have a standad Cozy wing and mines a little different.

Fussing with all the little variables that WORK is NOT a good idea. Everything interrelates. "Fixing" this...and "fixing" that is a good way to screw EVERYTHING up. I have tried to balance this, and MY BW's are based on the below.

My .02 centavos.

 

To Recap MY IO540 Cozy and how it relates to these BW's I did:

 

I have a 8-3/8 inch longer nose, no stretch to the airframe body. Room for ballast with a longer arm. I have a 10 pound oil heater up there. Maybe a battery-we shall see. This added nose through its center body will generate slightly more lift at higher angles of attack.

Standard shorter Cozy canard overall length. Located in the plans position with plans incidence.

I have a one inch longer nose gear strut.

I am working on added fuel in the strakes, with wet LE's and only 5 inch deep rear side baggage areas, Cozy Girrrls elbow openings. Shooting for max 33 gallons per side. Fuel will be weighted slightly more forward than plans. No center sump as in the other Cozy540's.

All the above considerations, led me to add the 8" foam blocks to the outside of the plans wings . Therefore my Vert stabilizers are wider than a standard Cozy by that much. Small added carrying capacity to the main wings for the 540 CG balance. The FS for my Vert S's, Steve, appears to be about a 2.5 inch change from plans, not 4 inches. For a 0360 powered Cozy, cut the wing tips back the distance of the blend, I would think. 'Course that changes the leading edge of the Vert stab's forward as well.

 

I am okay with it. Lets see if my plane likes it.

 

As always, this is what I have done, for the reasons posted, and YMMV depending on all your parameters.