Berkut Kit

Here is the finished T-Tapes

 

Pic 1) T-Tape on the inboard spar rib.

Pic 2) T-Tape on the outbaord spar rib

 

 

 

Lynn

 

One other thing. The T-tape layup was in lieu of the micro "shelf" that runs along the top and bottom of the spar cap. Which probably would've taken just as long to do.

 

Tony

If you are following Daves lead you can't go wrong. the micro shelf must be a Berkut specific method. on the berkut the forward spar face is set into the spar about even with the sparcaps and on the long /cozy it is 2" forward of the spar caps. I believe that is how Dave got back some of the fuel capacity and space taken up by the gear leg wells

micro shelf must be a Berkut specific method

I believe you are correct. I haven't seen anyone else do that.

 

on the berkut the forward spar face is set into the spar about even with the sparcaps and on the long /cozy it is 2" forward of the spar caps. I believe that is how Dave got back some of the fuel capacity and space taken up by the gear leg wells

That makes sense to me.

 

Just a quick observation here, John Matcho if you are out there what happens at the end of this page? Do we have to move the thread or will I have to stop posting?(it says last page, for page 11) I don't know how much of this build we can fit onto this site. I may have to get my own site like James Redmond has.

 

Tony

Tony

A quick look at the open ez thread shows 16 pages so far.

When you open that thread it shows pages one throught 10- last page.

I think you are ok for now.

I don't know how much of this build we can fit onto this site. I may have to get my own site like James Redmond has.

 

Tony

Generally (GENERALLY!) a forum is a chat venue. If you want/need a domain name to host a pile of files, bunch of pix, hi-res videos, there's a bunch on the forum that can assist. Often, the cost is minimal.

 

Rick

Well

 

I don't have alot of time for that. I would've started that process already. lack of time is a big problem for me. This site is already up and running it only takes a few minutes to snap off some pics throw up a description and I'm off and running. Maybe I'll look into a site that I can easily maintane. It needs to be fast and simple though.

 

Tony

Tony!!! Keep doing what you're doing. It's great reading, I'm sure, for many that don't reply. The pictures are great as well as the narrative. Keep it up!

John

 

O.K. I'll do just that. I just wanted to make sure I wasn't using up all of your web space. On that note. I want to thank you for keeping this site running. I really enjoy sharing what I'm doing. I probably wouldn't if it wasn't for this site.

 

Thank You:)

 

Tony

The T-tapes for the spar bulkheads ARE overkill, but it's an elegant way of dealing with blind edges that need some kind of bond.

 

I'd suggest you get a tube (Tubes? 2 tubes and a static mixer) of Pro-Set adhesive for the actual final installation of the spar forward face. It doesn't make much difference here - you could just use flox - but it makes for a significantly easier installation when you go close out the strakes, and you might as well get some experience with it now, on the little thing.

 

And don't make yourself crazy with the blended winglets. When you're done, if you're still up for that last 1%, we can develop a good set of pen-nib fairings that will get you just as much as the blended would, for 1/100th the work.

 

 

Here is the finished T-Tapes

 

Pic 1) T-Tape on the inboard spar rib.

Pic 2) T-Tape on the outbaord spar rib

 

 

 

Lynn

 

One other thing. The T-tape layup was in lieu of the micro "shelf" that runs along the top and bottom of the spar cap. Which probably would've taken just as long to do.

 

Tony

Sorry guys, I've been a bit busy lately. Today was the first real day that I've been able to work on the airplane. I did manage to finish up the T-Tape layups last week, pretty boring stuff. I just repeated what I did on the other side. Now that the T-Tapes are done. I had to order some 3M dp460 adhesive from Mcmaster Carr. Dp460 is the stuff Dave R. uses to adhere aluminum to fiberglass. Once I have the Dp460 I can begin the layups for the wing attach area. While I'm waiting for my shipment, I took the liberty of getting things ready for the spar face close out. Here it is. (Just a quick note. I never liked the idea of drilling blind thru these spar faces. In order to not make the same mistake Walt Sally made. I had an idea that I think will work very well for drilling the spar and wings)

 

Pic 1) The first thing I had to do was project the center of the aluminum pad above the spar cap. I achieved this, by using a square positioned at the center mark.

 

Pic 2) I measured from the square to the edge of the spar cap.

 

Pic 3) I translated the measurement to the spar face and made a mark. Using my circle template. I drew a 1"in circle around my center mark. If done correctly, you should be directly over the aluminum attach point center mark. using the 1"in hole saw attached to the drill press. I drilled a hole on my mark.

 

Pic 4) As you can see, I'm directly over the center mark on the aluminum.

 

Pic 5) This is the backside of the spar face. Just prior to drilling the hole, I used duct tape on the back of the spar face so, 1) there would'nt be any fraying of the edge. 2) So the back of the plug from the hole saw would have a perfect circle of duct tape on it, as a "release" when I put it back in the hole.

Pic 1) I removed the duct tape and sanded around the hole.

 

Pic 2) I layed up 2 plys of bid over the hole and covered it with peel ply.

 

Pic 3) Here are the centers of the holes from the hole saw with duct tape on the back. As mentioned before, this will be my "release".

 

Pic 4) Here are the plugs back in their respective holes

 

Pic 5) I clamped everything together between alumium blocks.

 

Once this all cures. I'll go back and drill a .750" hole in the center of this hole

leaving an 1/8in lip all the way around. Once I've drilled my wings. I simply drop the plug in the hole with flox and layup two plys of bid over the top.

 

Tony

Now that the T-Tapes are done. I had to order some 3M dp460 adhesive from Mcmaster Carr. Dp460 is the stuff Dave R. uses to adhere aluminum to fiberglass.

I never heard that one before. I'll have to make a note of it!

I started on the Engine mounts tonight. Here are the pics.

 

Pic 1) The engine mount angles are made from 1/4in birch per plans. I have this hudge sheet of 1/4in phenolic so I opted to use that instead. The engine mount triangles are 3"in apart from one another. So in order to keep things coplanar. I used a 3x3x5in piece of extrusion, I made a mark in the middle of the block. I held each triangle agianst the block and lined up the red mark on the block with the red line on the firewall. Once lined up, I superglued the engine mounts in place. Notice that I tapered the edges that are facing the firewall. The edges facing the fuselage are tapered as well. This is per plans.

 

Pic 2) Here are the mounts glued in place. Don't worry I went back and sanded the other two pieces of phenolic:D . There are several plys of fiberglass that will join the mounts to the fuse and firewall.

OOOO man you are my hero

 

more pics,

more pics

more pics

one foto said more than 1000 words:)

Wolfman

 

I'm glad you are enjoying the posts. I'm haveing a blast as well. I just wish I had more time to build.

 

Tony

I just wish I had more time to build

Job? You don't need no stinkin' job ... just keep building (and posting pix, of course). That way we can live through you vicariously and keep our jobs

I wish I'd known. I have a lot of parts tucked away that you could have taken molds from.

That's a great news for us but I dont think that's a big problem to design moulds from Berkut drawings with proper software (like Inventor, SolidWorks, Catia etc) and some skills. The biggest problem is to design proper layup schedule (of course you can make stress simulation for complete fuselage but I wont be able to do this in near future) I know Marc can do this without any problems.

I'm wondering do you remember layup schedule for the Berkut fuselage or is that possible to find this info in the Berkut drawings because I've not bought these drawings yet (so I'm not sure). If you dont remember I have one more question do you (or anybody who's reading this thread) know some good books about designing composite structures (I have few books about how to design alloy or wood plane but I cant find good books for composite ones).

Short NTSB report about inproper fusealage design builder paid highest price.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20020917X03709&key=1

 

I attached few pictures "How to design moulds from Berkut drawings" Please Note this is only sample which I did yesterday so it isnt quality job.

 

Mak

...The biggest problem is to design proper layup schedule (of course you can make stress simulation for complete fuselage but I wont be able to do this in near future) I know Marc can do this without any problems.

You give me way too much credit. This is non trivial, and rarely optimized in these aircraft. There would be problems :-).

 

At any rate, it is most likely that for the main fuselage layups (not localized reinforcements, but the main skins, both internal and out), structural requirements (stiffness, strength) were not the driving factors - damage tolerance from tools, knees and elbows was. This is at least likely to be the case for the Long-EZ, COZY, etc. - Richard may be able to address the issue for the Berkut.

Mak

 

split the fuselage horizontally down the side. The fuselage has 2 plys of bid on the inside. Not sure what the outside is. I can find out. If the Berkut is going to be resurrected it really needs more modern layup techniques to build it in a timely fashion. There are alot of improvements that can be made to the kit to make it easier for the builder to assemble. I would really like to see more precision of wing and spar attachment. Either by a fixture or predrilled plates. The other thing that is unfortunate, the composite kit market is very soft. Vans has done very well with the Rv's, I can see why! they are fairly easy to assemble. Not to mention the shear number of RV kits sold and flying. Builders can wrap their minds around aluminum, screws, and rivets. When it comes to composites, builders tend to choose metal. So I think the Berkut needs to be "easier" to build by that I mean faster to build.(Tab-A goes into Slot-B) I think that can be accomplished with more modern tooling techniques.

 

off the soap box, gotta go build now.

 

Tony

You give me way too much credit

I think you underestimate yourself:D I read somewhere that you work for scaled and you were responsible for blended winglets layup schedule as well and of course I read your posts here. I wish I'll have half of your knowledge in the next 10 years. (I really need to find few good books if I want to raise my knowledge level).

This is non trivial, and rarely optimized in these aircraft

Of course if something works fine why we should change that I've never heard about structular failure caused by design errors in Long Ez. I'm wondering did Dave make some calculations or just based on his experience, I've seen an interview with him on Discovery channel and he said that he doesnt have proper aeronautics education and he is mostly self-taught (that interview wasnt in English so I'm not sure about translation quality besides everybody knows that TV lies:) )

structural requirements (stiffness, strength) were not the driving factors - damage tolerance from tools, knees and elbows was

I'm really surprised about this but it's all about composites It's much easier to work with alloy. (Is that any mathematics formula for these damages or just damage tolerance [safety factors] how many percent)

 

There are alot of improvements that can be made to the kit to make it easier for the builder to assemble

Of course but the Berkut was designed 18-19? years ago without all this modern software which can simplify our work today.

I can see why! they are fairly easy to assemble

Everything what you need to do is make some holes and put some rivets thats all it's much easier to build alloy plane then composites. For composites you need more skills and knowledge (my opinion). You don't need to worry about cure temp, time air bubbles etc when you are building alloy plane. I've seen open workshop day (photos) in the Sonex factory? I dont remember anyway even 8-10 years old kids were able to make some holes and put some rivets or simply bending.

gotta go build now

Btw are you going to work in new year as well:D Which part of your plane are you going to do next canard, wings or strakes?

 

Mak

I think you underestimate yourself:D I read somewhere that you work for scaled and you were responsible for blended winglets layup schedule as well

Yeah Marc ....... quit underestimating yourself so much!

 

On the subject of the Blended Winglet .... don't forget Jack! He was the one who came up with the Idea as it applies to a canard as well as actually build and flight test it!

 

On the subject of modern computer software resources and what a designer/engineer can do with it: It is amazing but what will always truly impress me are the guys at the "Skunk Works" that came up with the SR-71 in "how many months?" Using slide rules? (Everyone who has ever worked a slide rule, please stand up.) Now that's impressive.

 

Don't be intimidated by composite structures and the processes involved. I screwed up the same bulkhead three times. It got to the point I could build it from scratch in 4 hours or less. By the time you get to the big stuff you have it figured out.

 

I started my Long-EZ in April of this year. My neighbor started his single seat LSA spam can about the same time. I have my fuselage through chapter nine, plus my canard and he has a left wing.

On the subject of the Blended Winglet .... don't forget Jack! He was the one who came up with the Idea as it applies to a canard as well as actually build and flight test it!.

Of course you are right Jack came up with the Idea and probably he did all "dirty job" but I was talking about layup schedule which if I remember corectly was designed but by Marc.

It is amazing but what will always truly impress me are the guys at the "Skunk Works" that came up with the SR-71 in "how many months?" Using slide rules?

I'm afriad they don't make engineers like that any more.

 

Mak

Everyone who has ever worked a slide rule, please stand up.

um.. aren't those flight computers that they teach you how to use in groundschool a form of slide rule? IIRC, Richard Feynman prefered the circular slide rules. He claimed they acheived high accuracy in a smaller form-factor than linear rules.

 

However, the fact that pretty much every pilot today knows how to use a slide rule doesn't change the fact that the guys at skunkworks were superstars.

uhhh ..... more like this:

http://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Sliderule.PickettN902T.agr.jpg/800px-

TMann,

 

I got one of those, AND, I know how to use it.

 

The one in the photo looks good to 2 decimal places. We had one in our physics lab (Way Back When) that was 6 ft long, it was good to 4 or 5 places if I remember correctly

 

Damn am I old :o

 

Waiter

TMann,

 

I got one of those, AND, I know how to use it.

 

Damn am I old :o

 

Waiter

I must be older ......... I have one and FORGOT how to use it!