blended think tank

[Marc Zeitlin]

I think there are some layups in the internal structure as well, not just foam. Correct?

Correct. There are numerous, multiple ply layups internal to the plans winglet attach scheme. They act as "ribs" both for the winglet and wing tip, and as compression members to deal with the forces/stresses imposed by the tension in the lateral external layups.

 

What foam is in the internal winglet attach area is almost meaningless - it's the layups that take the compressive and shear stresses, not the foam.

[TMann]

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. )

I waiting on my vacuum pump to catch up and have a little time to kill and my stack of CPs is handy so I thought I would look this one up. I distinctly remember the incident so it was fairly easy to find.

 

CP #33 page 5.

 

It's a very clear example as to how even a small change can cause major failure.

 

Look it up.

[steve]

.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).

 

 

how odd you would say this ? ?

the blend i did turns out to be the same you told jack to do

did you forget what you said?

[Drew Swenson]

There is a very long thread ("blended winglets") with Marc pointing out that Jack and company did not follow his instructions----and with all comers readily admitting that they did not follow his instructions. Does not appear that Marc has changed his opinion on his own advice.

[Jack Morrison]

I did not want to get involved in this issue but your statement Drew is absolutely untrue, (Jack and company, me ,myself and I) did exactly as Mark suggested and sent to me. I wish that people would not comment on issues which they no nothing about. I sent my drawings to Mark in 2005 about the blended winglets ( I will post a copy of the original drawing as soon as possible). I weighed blending the winglet already attached to the wing, which are what Mark drew up for me and has on his wed site and was also on the forum. I did not like this process and decided to go with the new winglets with the extension or continuation of the wing shear web and spar cap to the top of the winglet, my design. Mark furnished the techinical information for the proper layups for structural strength, period. I do not recall ever mentioning the size of the radius of the blend but if you look at the original drawing I sent to Mark, the12 inch radius is not accurate. A 12 inch (circumference) is closer to the blend on my winglet, actually the outside of the radius came out to 13.5 inches, the inside 6 inches is circumference, not diameter. This is the blended winglet I designed and installed on my E Racer. I tested the AC in all attitudes and they performed almost exactly as I hoped they would. I alone decided how large the circumference during my design process to keep the bottom of the rudder as low as possible, the larger the blend, the higher the bottom of the rudder is. I also designed all the linkage, a very simple system. I will post the drawing as soon as I figure out how to attach to the web site. I have the right winglet with a portion of the wing saved from E Racer113 and in the near future will test the actual strength of the blended winglet as I designed. I will do a professional video of the actual test, outside to limits and inside to destruction.I will send this video to Mark for what ever he wishes to do with it. Mark was a tremendous help in this program and I would have never attempted this on my own. I wasn't born yesterday but techenical and structural knowledge is a must with a serious modification like the blended winglet. Just setting the record straight.

 

Jack

[Drew Swenson]

Jack,

My comments are on the thread called "blended winglet." I reread the whole thread---my statements are correct. If the written record within that thread is incorrect---of which many of the words are yours---then you may want to correct the record---and get Marc to do so as well.

 

I am not privy to any private conversations you have had---and I of course cannot make comments on conversations I have never heard. But reading both your last post and this one still makes me scratch my head.

 

As an outsider (not privy to all the private conversation)---reading both threads---it appears that Marc drew up a blended wing with the proper amount of layups---then you changed the drawing to a different blended wing and kept the original layups from Marc's drawing. What is unclear is if the change in blended wing required a change in layup.

[TMann]

This is really a bad place to hammer out structural issues and modifications. If you are TRULY interested in this mod, I would suggest that you contact the consulting parties offline ........ and be preprared to pay for the information you get.

 

Most of this thread is a cluster of second hand conversations. The danger here is the possibilty of a builder thinking that this thread contains enough information to perform this mod. As stated earlier, CP #33 contains the results of one such venture.

 

I plan on doing this mod. I have discussed it with Marc and Jack. I do not intend to proceed with it without a complete vetting of the procedure as I understand it. Very few builders on the forum (myself included) have the expertice to safely do this on thier own.

 

It a lot easier to part with some bucks than to part with your life.

 

We now return you to your regularly scheduled program

[Drew Swenson]

...what Tmann said...

[steve]

.

 

#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.

now that iv done it, the answers are easy

when you the sheer web, jig like the plans and support the end of the winglet

and lay up the hole web at one time.[\end]

 

i did the bottom tapes as one, but cut them 3 feet longer for the stab and let them dangle until i got the wing part done then trimmed and did the stab.

but it was a lot of work and later just tapered the wing tape then the next night i did the stab and tapered over the wing tape. doing it in two parts was a lot smarter.

#3. it was tested to 175knt in a full slip (can we say the force of a sail boat)

if you blend it, there is no way to keep the top and bottom skins from coming apart as you load the winglet. the old way has inside layups to do that very thing. that is why i did the sher web (I-BEAM), you have something holding it together. the rest is simple. i don't know about Jacks but mine is the same hight as per plans and has the same "wrt "mark. but if i stand back and look, i thing it has a one deg tilt inward.

 

PS. Marc has never seen my plane or my work on it, and has not helped build it. there are lots of builder that have seen it and " all " of them do not need or want a ten foot pole.*end of rant*

[Neverquit]

but if i stand back and look, i thing it has a one deg tilt inward.

 

 

You're kidding, right?

[longez360]

...what Tmann said...

I concur.

 

... and structural justification is only part of the requirement. Let's hope the few knots one might see in cruise and the ramp 'wank', excuse me, 'wow' factor are worth the risk of a structurally unjustified, perhaps partically flight tested 'mod' one might choose to emply. Seeking qualified assistance is key.

[longez360]

...what Tmann said...

I concur. Well said.

 

... and structural justification is only part of the requirement. Let's hope the few knots one might see in cruise and the ramp 'wank', excuse me, 'wow' factor are worth the risk of a structurally unjustified, perhaps partically flight tested 'mod' one might choose to emply. Seeking qualified assistance is key.