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blended think tank


steve

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i need the thinkers on this one

the plan...to blend the wing end be for i remove it from the jig

why?....so i can lay-up the spar tape and sher web all at the same time

it would also be cool to add the wing-let at the same time'

i think i can do it, i just need the tilt Angle and the offset

the plan give measurements from the corner of the inner aileron and will be of no use to me.

anyone know the slant back Angel of the wing let?

and is it tipped in at the top or square ?

is the wing let as a hole set square to the wind or is it turned in a little?

any body doing this yet ?

Steve M. Parkins

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Steve,

You can get this info by setting your cores in place (as if they were already skinned). Take your measuments to get all your angles and build a winglet jig in the process.

 

From what I have researched so far I believe the angle of incidence for the winglet is 1 degree.

 

Yes ..... a continous shear web and spar cap would be ideal but you may have to modify that approach somewhat (unless you dug a hole in your shop at the end of your table.) You do the bottom spar cap first an getting to that inverted wing tip may be a challenge.

 

If you could accurately jig it nose up (like you do for the shear web) and work through the bottom skin in that configuration, you would be good to go.

 

It's a real head scratcher

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I've thought of doing the same thing, but am leaning against it. Here's why:

 

#1. More difficult, overall. I hate doing long layups, so much easier to split the job up. Spready spar cap tape over a curve is much more difficult than laying it out straight.

 

#2. Harder to vacuum bag. I'm vacuum bagging the wings. It'll be very difficult to get the whole winglet / wing assembly into a single bag and avoid having the bag pull the winglet one way or another.

 

#4. Possibly heavier. The spar tape is heavy, if it isn't needed, don't bother.

 

#3. Why bother? The winglet doesn't see enough force on it to require a thick spar. The plans method of using BID layups seems to work fine. I'd rather not add weight.

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guys,

how do you build the curved foam piece that links the wing to the winglet?

and how do you make the spar trough on a curved surface? I mean, it's not possible to hotwire it or at least I do not see how I could.

are you using the same wing blue foam or a superior density?

Roads? Where we're going we don't need roads. (Dr. Emmett Brown)

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I have not cut mine out yet but in theory

I created a wing template that sits about 9 inches inside the the outboard edge of the wing.

You hotwire from there to the wing tip FLAT.

Next you hotwire from the wing tip to the bottom template of the winglet (pitched up by 1 degree.)

The trough is cut after the wing shape to conform to the depth at the wingtip for the area from the wing tip to the top of the winglet.

I have a hotwire template that is a series of 5 degree 'V' shapes.

Mark the top & bottom of the cores when assembled to assist in proper alignment.

Lay the core in the waste foam, weight and hotwire the 'V' cuts out. Assemble the shapes with 3M 78 and clean it up with a little sanding and you ready to move on to the next step.

 

Anyone else thought through this?

 

I have some extra foam to make a dry run and test it out prior to actual fabrication.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I have not cut mine out yet but in theory

I created a wing template that sits about 9 inches inside the the outboard edge of the wing.

You hotwire from there to the wing tip FLAT.

Next you hotwire from the wing tip to the bottom template of the winglet (pitched up by 1 degree.)

The trough is cut after the wing shape to conform to the depth at the wingtip for the area from the wing tip to the top of the winglet.

I have a hotwire template that is a series of 5 degree 'V' shapes.

Mark the top & bottom of the cores when assembled to assist in proper alignment.

Lay the core in the waste foam, weight and hotwire the 'V' cuts out. Assemble the shapes with 3M 78 and clean it up with a little sanding and you ready to move on to the next step.

 

Anyone else thought through this?

 

I have some extra foam to make a dry run and test it out prior to actual fabrication.

think we on the same page i think (i got lost, i need pics)

i cut off 7" off wing end (so that after the bend in done it will still be plans length). then made sixteen 1 by 3 by 27" (1/2"by 1") V . put them together and you have a curve, but i will cut them all to look like the wing end be for i glue them on the wing.

i can drill in all the holes i need as well.

the trick (guess) will be as i assemble them i will set them back each one a 1/8" so it should look like the back sweep i hope.

I'll have it done by tonight, we see

Steve M. Parkins

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You may want to precut the routing of your rudder cable while you're at it.

 

Post pics Steve.

Also .... talk to Jack.

i lost phone/camera.

i got my old one but we see.

this thing is way cool and hard on the brain:irked:

two big bobos right off the bat.

can some one do my math

first off on the 102.15, is that to the center Le of the lower wing let ? IE

the measurement from the aileron corner to the front outer wing(4.5 back).

if it is, then my best guess is I'm now 103.25

so i rounded out the rear measurement to 109 from 108.?35

i need the % that i added so i can add it to the last measurement (aileron-to-tiptop wing let)

Steve M. Parkins

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think we on the same page i think (i got lost, i need pics)

i cut off 7" off wing end (so that after the bend in done it will still be plans length).

Does the wing need to be plans length with the blend? What did Jack Morrison do? Did he cut off any portion of his wing to fit the blend, or did he just add the blend to the end of the wing?

 

This point if pretty important.

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I figured on starting the blend 9.5 inches back from the wing tip.

Working on a radius of 12 inches, the length of the blend going from horizontal to vertical is 18.85 inches which put the original wingtip dimention midway through the blend.

 

.......... in theory.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I figured on starting the blend 9.5 inches back from the wing tip.

Working on a radius of 12 inches, the length of the blend going from horizontal to vertical is 18.85 inches which put the original wingtip dimention midway through the blend.

 

.......... in theory.

What "theory"??? Why 9.5" ??? What analysis, calculations are you people doing when selecting the length or amount of the wing to cut off?

 

I'm not at all convinced that it's as simple as just "shortened wing + blend = orginal wing length" Maybe it is, but maybe it isn't.

 

I like the idea and will most likely go this route for drag reduction, but I'll be damned if I just pick some arbitrary wing length and start cutting. If you don't have the experience neccessary to analyze aorodynamics, find someone who does and inform the rest of us.

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then made sixteen 1 by 3 by 27" (1/2"by 1") V . put them together and you have a curve, but i will cut them all to look like the wing end be for i glue them on the wing.

 

Steve, why not just use a solid piece of foam? Use your wing tip template on one end that will attach to the wing. Trace the template and affix it to the wing tip temporarily. Follow the leading edge angle up the foam block. Trace the verticle stab template at the top of the block where you'll put the leading edge of the verticle stab (I think its 4 or 7 inches back). Then blend the two leading edges together. Take off the block and sand the transition between the two templates.
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If you don't have the experience neccessary to analyze aorodynamics, find someone who does and inform the rest of us.

What makes you think I'm 'winging it' on my own.

I'm not walking into this blind.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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What makes you think I'm 'winging it' on my own.

I'm not walking into this blind.

I hope not. But what calculations did you perform to ensure that the blended winglet + wing area, length etc... imparts the same center of lift characteristics to the aicraft?

 

The Mk IV is swept wing design, placing the end of the wing behind the aircraft's center of lift and center of gravity... Changing the characteristics of the end of the wing adds or reduces lift behind the aircraft's CG. That'll change the stall characteristics. Move that center of lift too far forward, and you could end up with the center of lift too close too/ahead of the CG, giving you a nice deep stall.

 

If you know how to calculate the lift distribution of your particular flavor of blended wing/winglet, I would be very interested in that information, as would many others.

 

If not, I'd suggest copying, exactly, Jack Morrison's mod, since we know his didn't have adverse consequences.

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If not, I'd suggest copying, exactly, Jack Morrison's mod, since we know his didn't have adverse consequences.

yeah, good Idea. I'll see if I can get in touch with him.

Thanks.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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...If not, I'd suggest copying, exactly, Jack Morrison's mod, since we know his didn't have adverse consequences.

I'd hoped to stay out of this mess, but in the interest of on-lookers' safety, I've got to say some stuff.

 

First, as the person who advised on the aerodynamics of Jack's blended winglet implementation and designed the structural modifications that he used successfully (and so far, the ONLY successful implementation of blended winglets on a Rutan Derivative canard aircraft), I think that I have a bit of authority on this matter.

 

Secondly, there are only three people that have asked for and received my assistance with blended winglets - one on an E-Racer, one on a COZY, and one on a Long-EZ. Only the E-Racer (Jack's) has flown. I don't know when the others will do so.

 

Thirdly, I have been approached for engineering assistance with this modification by a few other Long-EZ builders, none of whom have followed through with me on getting that assistance (yet). At least one of those folks is here on this forum stating that they're implementing this modification. They have stated that they will not be proceeding with actual fabrication until they've received my input.

 

Fourth, there is at least one person (not on this forum - the current admin of the defunct "Canard Community Forum") who, in my opinion, is building an extremely dangerous blended winglet design from a structural standpoint, going from what he writes on his blog. (And who knows what he's doing from an aerodynamic standpoint - I wasn't able to decipher the description of the winglet positioning or angles). He is essentially following Steve Innova's question #3 from the third post in this thread:

 

"#3. Why bother? The winglet doesn't see enough force on it to require a thick spar. The plans method of using BID layups seems to work fine. I'd rather not add weight."

 

First of all, the plans method uses a large assortment of mostly UNI and also BID layups, both internally and externally - it's not just BID.

 

Secondly, the answer here is that the blended winglet has completely different load paths and skin buckling issues than does the plans winglet, and leaving out either a shear web/spar cap arrangement, or another internal support structure (one of which I provided to Jack as an alternative when we were working on his E-Racer) is begging for trouble. If this path (no internal structure) is taken, I would suggest a FULL Limit-Load test plan for the new winglets (and this is something that I have implemented with Jack for his new aircraft design - just ask him what's involved in the test procedure, and how much weight is needed, if he'll tell you before the unveiling).

 

Unless a builder either follows a proven structural methodology or full Limit Load static proof testing, I would not touch their aircraft with a blended winglet implementation with a 10-foot pole, much less fly in it. My reading of Mr. Parkins' actions along this line put his airplane into this category (not withstanding any other issues I've got with it).

 

Steve Innova asks some good questions, and unless there's another qualified engineer out there advising canard folks on blended winglet designs, I'm not aware of these answers having been provided to those others building or contemplating this modification. It's a lot more complex than just taking some subset of the plans layups and calling it good, and there are more aerodynamic issues than just what the radius of the blend is.

 

This is NOT something where free advice will be dispensed, given the extreme safety issues involved.

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I agree with Mark 100%.

 

In addition:

 

While one may dream of the 3 knots picked up in cruise with a 235 or 320 powered EZ with blended winglets, consider the aerodynamic efffects (unkown for your aircraft I can assure you) and structural integrity that goes with a change and weigh it up against your life, that of a test pilot, that of a passenger (if you make it that far) and those of people on the ground who didn't get a say...

 

Some videos on flutter or winglet stall would really be a nice addition to this thread.

 

Does anyone recall the Vari-Eze accident where the builder forgot the layups on the outside of his winglets? He was killed as was his daughter. A winglet modification that has not been engineered may result in the same mistake. It may be unintentional. Does anyone recall the effects of removing the lower winglet on a cozy IV?

 

Mark has flight test data for a Morrison E-Racer. Can any of the other people making this mod explain the aerodynamic and structural effects and their justification to me prior to flight test? I'd like to hear them and how they arrived at that justification... It probably needs to be more than it worked on an ERacer. :-)

Cheers,

 

Wayne Blackler

IO-360 Long EZ

VH-WEZ (N360WZ)

Melbourne, AUSTRALIA

http://v2.ez.org/feature/F0411-1/F0411-1.htm

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Does anyone recall the Vari-Eze accident where the builder forgot the layups on the outside of his winglets?

I don't think he forgot them. It was more of a case where he had a "better Idea."

 

I'm currently brainstorming how to fabricate the shape of the blend. The actual fabrication and layup configuration will be left to my consultant/engineer.

It's like anything else ...... you get what you pay for. I'm not looking for a cheap plane but I do want a solid plane.

 

I chat with Jack from time to time and while his new plane is pretty extreme, he is doing it the right way. Getting professional input. An example I intend to follow.

 

As I stated before, I'm not winging it on my own here.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I'm currently brainstorming how to fabricate the shape of the blend. The actual fabrication and layup configuration will be left to my consultant/engineer.

It's not just the structural issues of the attachment. That's relatively easy to test, assuming you're willing to build a test article and test it to destruction.

 

But there are substantial aerodyanamic considerations too, depending on where you start the blend.

 

Don't forget, the airfoil has twist to it. With each additional inch of wing you're removing, the characteristics of the airfoil change ever so slightly.

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It's not just the structural issues of the attachment. That's relatively easy to test, assuming you're willing to build a test article and test it to destruction.

 

But there are substantial aerodyanamic considerations too, depending on where you start the blend.

 

Don't forget, the airfoil has twist to it. With each additional inch of wing you're removing, the characteristics of the airfoil change ever so slightly.

The actual fabrication and layup configuration will be left to my consultant/engineer. (get it ........ I'm working with Marc on this)

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I'll make an offer to anyone who is really set on blending their wings:

 

I have in my possession two (2) wings and winglets. One has have some minor defects in the wing root area -- probably not enough to scrap them, but since I didn't build them I've already decided not to build new ones from scratch.

 

For a reasonable price, I will sell you these mostly good wings & winglets, which you can then use for destructive testing of your particular blended wing design.

 

There are several articles on how the Rutan Aircraft Company (or was it CSA?) destructively tested the wing/winglet for a long-ez. That should give you good baseline data. Or build one to plans, the other blended.

 

Unless the design is validated with at least static load testing, I wouldn't fly under blended winglets.

 

-- One more thing. Dust's blog (not so much a forum any more) has interesting pictures on how to shape the foam for a blended winglet, but if he is using no spar or other reinforcements to hold the winglet on, I would steer far clear of that design.

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I'll make an offer to anyone who is really set on blending their wings:

:rolleyes: hmmmmmmm ........... buy Steve's wings or spend that money on a qualified engineer .............. man, that's a tough one. :D

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I migyht offer them for free, but I've had a couple times where I've gone to the trouble & expense of crating something up for someone and then they back out when they find out how much shipping costs. Funny thing is though, when someone's already paid for it, they seem to be more likely to follow through with actually picking it up/shipping it.

 

I also don't really want these wings to fly on someone's airplane. These are for destructive testing. If no one wants them for a couple hundred bucks, I'll set up a test rig and report the results.

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Qualified, schmolified. The engineer isn't building the wing, you are. You're not just testing the layup schedule with destructive testing, you're also testing your skill properly executing the engineer's plan.

 

I'm testing my shoulder harness attach points using destructive testing. Sure it takes a lot more time to build a test article, set up a test stand, procure the 2000 lbs of sand weight etc...

 

But I'll know it's safe.

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