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Berkut Kit


tonyslongez

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  • 2 months later...

In the last few months Dale and I worked on the cowls for the Berkut. Now just to be clear the cowls are pretty good for the 360 but they aren't perfect. So I set out to accomplish a few things. First, I wanted to make the cowls symmetrical. In order to do this, we had to pile on the body filler and basically make a plug. Second I wanted Dale to teach me how to make a mold. So here is what we accomplished.

 

1) This is the right side of the cowling. You can clearly see the template shape

 

2) When you hold the template level there is clearly a discrepancy not bad but needs to be fixed

 

3) Here is alot of body filler about an inch thick in some places but definately getting better

 

4) Rear right side template

 

5) Left side template about a quarter to half of an inch low in this area very symmetrical now.

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6) Here is the right side of the cowl now, much better :D

 

Well I thought that I had pics of the plug for the cowls but I don't.

I do however have pics of the final cowls pulled from the molds that we made.

 

These are 4 plys of 3k 2x2 twill vacuum bagged with MGS 285 post cured at 140deg for 11 hours super light and stiff

 

Tony

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Tony, you report a difference in the cowl symmetry: did you also check the fuselage for left/right symmetry?

building a rounded fuselage I found that this is one of the most time consuming aspect of the job and although I'm using a professional automotive bench I see that it's almost impossible to do better than a 1 millimeter clearance(difference) between left and right.

this is basically due to the fact that every measurement that you take on a curved surface can have a small error and half millimeter on the right side and half on the left side give you a total of 1 millimeter error that I do not think to be really influent on my aircraft behaviour but nevertheless make me scratch my head.

do you think the berkut is perfectly symmetrical?

to know that the berkut has this kind of problems too makes me more comfortable......

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

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Hi Tony nice to see you again:)

 

I was worried that you left, I moved to homebuiltairplanes.com, I like Berkuts but I'm not really into standard LongEze's. Anyway thanks for updates I'm hoping for more in the future, I really like your new carbon cowls nice work. Wish you well with your project, please post more pics of your bird, carry on and keep posting!

First order of business are the canopy hinges that Mac790 rendered

Nice to hear that my renderings were helpful.

 

Take care.

Seb

 

btw have you built wings?

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did you also check the fuselage for left/right symmetry?

Airnico

 

No I haven't checked the entire fuselage yet. The nose is a little off that I can see right now. We'll make more templates and check the fuse for symmetry later. Overall I think it's pretty good.

 

do you think the berkut is perfectly symmetrical?

No not "perfectly" symmetrical. But pretty good. I'm happy with it except being slightly off at the nose. I can fix that.

 

 

Mak

 

The electrician comes this morning to hook up the HAAS. I'm going to get started on those hinges, You did a great job on them. I'll check out homebuiltairplanes.

 

Tony

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Tony ....... 2 questions:

1. Mak's drawing does not include a fixed point for attaching the hinge to the canopy. Am I missing someything here?

 

2. How does the nose you drafted (ez.org downloads) compare to the Berkut? In your drawing it appears to extend out to FS -24 compared to the plans FS -7.

 

I used your drawing as a starting point for my nose but stopped at FS -19.

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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TMann,

 

If I remember correctly, I made 2 or 3 different renderings so I'm not sure to which one Tony is referring. I think that my renderings were only some kind of inspiration for Tony, I believe that he solved all problems with attachments, we will see.

 

btw Nice to have discussion in this thread again, have been so quiet for last year.

 

Seb

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1. Mak's drawing does not include a fixed point for attaching the hinge to the canopy. Am I missing someything here?

T

 

No, The attach point to the canopy frame was cast into the hinge. If you look at the renderings in the post for canopy's and doors section of the forum you can see that Mak redered that portion as well.

 

 

2. How does the nose you drafted (ez.org downloads) compare to the Berkut? In your drawing it appears to extend out to FS -24 compared to the plans FS -7.

Well, now that I have the Berkut and LongEz side by side. The nose for the longEz is about 4"in longer than the Berkut nose. I'm going to mold the Berkut nose and attach it to the longEz. Dale and I are going to cut the nose off of the longEz this weekend. I'll post the pics for you.

I'm going to try to make it a simple retrofit, without to much filling.

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You'd better believe Tony's Berkut WILL be symetrical. I've seen his and Dale's work first hand it is truly beautiful.

I was not refferring to the nose, it's quite simple to put the nose tip on the centerline, the hardest thing on a rounded fuselage is to get exactly the same left/right curvature(3 axes)from the firewall to the nose tip.

somewhere you could find that your fuselage is larger on left or on right and it's difficult to correct it because you have a shape that is rounded on all the 3 dimensions and when you make a change on 1 axis you change all the 3.

do you remember the rubik's cube? you try to adjust a face and you mess all the others....

 

Tony, great job fixing the cowl and great job with the new one!!!!

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

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NIco

 

Thanks. I'm glad you like it. I think we have to remeber that the plug for the Berkut was made with as best precision that was capable by hand at the time of conception. To be real precise you would need CNC. Now I think what Steve James (aka EZ AHAB) is doing at Eureka CNC is getting alot closer to that type of precision. To cut a fuselage on three axis you would need one hell of a big router even then you will find very slight inconsistencys

but that's what tolerances are for. Unless your going to kit, That would be serious work and money to put into a one off airplane. I don't think Dave R. had the time or the money for that.

 

Tony

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Tony, great job fixing the cowl and great job with the new one!!!!

Yes ..... Tony, It is quite cool! :cool2:

This is just the type of thing that drives the 'spam-canners' nuts.

 

I just love this stuff!

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 was not refferring to the nose, it's quite simple to put the nose tip on the centerline, the hardest thing on a rounded fuselage....

I wasn't refferring to just the nose. I meant the whole airplane including the rounded fuse but especially the wings, winglets, and canard :D

EUREKA CNC

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Extreme Precision CNC Hotwire Cutting

Perfection To The Core!

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> hmmm...a CNC'd larger (than EZ), rounded, Berkut like fuse out of foam,

> standard fuse layups...thow in bulkeads & longerons...hmmmmmm....

 

If you go that far, why not go a little further: make it a plug, build a mold, and then invite people to use that mold at your place for a modest fee to get some of the invested money back...

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2) When you hold the template level there is clearly a discrepancy not bad but needs to be fixed

Build it the way you want it of course, and your work looks magnificent, but is it possible the 'discrepancy' is due to the engine not being symetrical left/right? (i.e. placement of the cylinders).

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09
www.mykitlog.com/Spodman
www.sites.google.com/site/thespodplane/the-spodplane

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is it possible the 'discrepancy' is due to the engine not being symetrical left/right? (i.e. placement of the cylinders).

Well! maybe but I don't see any other cowlings that aren't symmetrical. So no I don't think that was it, if it was, that seems a bit silly to me. It's off in places that have nothing to do with the engine. Funny thing is I have a set of LongEz cowls that had the same problem. Also I have a set of 540 cowls that don't have those discrepencys (way more symmetrical). The 360 cowls didn't realy line up the way they where supposed to at all. so I don't think it was done that way on purpose. Besides they look alot better symmetrical. I talked with a few LongEz guys who did the same thing I did. The whole thing was just out of whack. It was kinda like someone held a heat gun to the left side and it just kinda wilted. The bottom was worse than the top. I got them just about perfect now

 

Tony

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