Berkut Plans

[Kent Ashton]

Bob Setzer has been working on his A-Solution for a few years now ...

 

http://www.canardzone.com/forum/topic/19036-a-solution/?hl=%2Bbob+%2Bsetzer+%2Ba-solution

And doing some nice work but according to his posts, he started 7 years ago (Spring of '07).  In Jan '13 he was still pulling molds.  I did not find anything since then.  

It's a lot of hard work.  To build a molded airplane, you have to build it three times:  plug, mold, then the part.  Of course, this is why Burt used moldless construction.   Molds only pay off if you are going into the business of supplying parts.

 

A Long-EZ can be built in two years if you have the space and tools and don't waste time.  The average guy will take four or five years.  50% do not finish at all.

[Sohail]

Kent, thanks. Good point... Keep it Stupid Simple and I may end up building AND flying the plane at some point :-)

 

Is there a comprehensive list of feature or central place that Long-EZ builders use to share the Berkut's enhancements in Long-EZ? I searched this site with various keywords but no hits...

 

I spoke with Bob Setzer last night. He said he is done with the mold and likely to sell cores in about six months. He admitted that it is slow going and he has not updated his "A-Solution" thread for a while (more like 5 years).

[magnum]

 

 

A Long-EZ can be built in two years if you have the space and tools and don't waste time.  The average guy will take four or five years.  50% do not finish at all.

 

    Yep, good points here. This is exactly why I bought an in progress project. Also the gull wing doors were a consideration to get in an out of it with back issues. A lot of things factor into a build and you have to consider what the mission is going to be and what suits you best. I get to go pickup my engine next week. Finally some progress for my stuff! 

     Good luck with your build and keep us posted.

~~~tg~~~

[AVI]

The Berkut uses a lot of carbon fiber at $40-50 per yard vs. $7-8 per yard for fiberglass.  

http://www.acpsales.com/Carbon-Fiber-Woven-Fabrics.html?gclid=CLOgio3r68QCFYQkgQod2hcAVw

 

 

Kent, you make some very valid points, but let's take this in perspective. 

 

The Berkut fuselage and winglets are glass, with some CF reinforcement in the fuselage. The spars also use CF, but we're mainly concerned with the wing skins.

 

The Bill of Materials for the LongEZ Chapter 19 (wing & ailerons) lists 56 yds of UND and 9 yds of BID.

 

So ballpark estimate ( mileage will vary with determined shoppers ) we're looking at approximately $2,000 - $2.500, maybe more, maybe less, for the cost of CF over the cost of Glass. Incidentally, this is the rough cost of a set of CNC cut foam cores.  Nobody said a Berkut clone could be built for less than the cost of a LongEZ. The RG components alone could add, according to estimates on the net, some $5,000 - $10,000 to the cost of the build. ( We're hoping for the lower amount. )

 

In the grand scheme of homebuilding, the additional cost of CF is relatively insignificant ( I don't state this lightly - we all have budgets ) in comparison with the overall expense of a project. What I'm trying to say without sounding condescending, or giving the impression that money doesn't matter, ( it does to me ) is that cloth material is not the most expensive item on the list. There are far more components which can drive the cost up way beyond the amount spent on CF.  I'm sure you're well aware of how costs can spiral. We don't have to be Boeing or General Dynamics to have cost overruns!

 

Seriously now, whether it's doable to properly wet out CF in a garage without the use of prepregs is perhaps more of a concern to me. 

[magnum]

 

Seriously now, whether it's doable to properly wet out CF in a garage without the use of prepregs is perhaps more of a concern to me. 

 

     I agree on this point also. I am building a fiberglass body for my race car and I am using black dye bid regular fiberglass and its very hard to see to wet it out evenly. I have adjusted my lighting and even tilted the table some to try to see it better. I would be very wary to try to do it with carbon fiber. 

    The only proper way would be with vacuum bagging everything for peace of mind.

    Just my 2 cents.....

~~~tg~~~

[Kent Ashton]

So ballpark estimate ( mileage will vary with determined shoppers ) we're looking at approximately $2,000 - $2.500 [extra, for carbon fiber] . . .The RG components alone could add, according to estimates on the net, some $5,000 - $10,000 to the cost of the build. ( We're hoping for the lower amount. )

 

You also gotta add the higher cost of the O-540, engine mount, prop.  And of course, you wouldn't put simple VFR avionics in your rocket.  :-)

 

 

I don't want to be a wet-blanket.  To be honest, after I saw what the late Zubair Kahn did to get his two-engine Cozy monstrosity re-engined and flying, I gained new respect for what an inexperienced builder can accomplish when he has a dream and is determined about it:

http://forum.canardaviation.com/showthread.php?t=5859

 

At least with the Berkut, there seem to be plans to follow.  That's a plus.  :-)

[Marc Zeitlin]

At least with the Berkut, there seem to be plans to follow.  That's a plus.  :-)

The plans are woefully incomplete. As are the drawings, which are neither complete nor accurate. Anyone interested in Berkuts should spend a lot of time talking to James Redmon, who has what is in my opinion the most beautiful and well engineered Berkut on the planet, and who works on them (and other canards) in the Dallas area. He will tell you that you would have a hard enough time building a Berkut from a kit, much less ab-initio.

 

With respect to Zubair, whom I liked very much as a human being, he is currently the "late" Zubair Khan because he did not listen to good advice regarding building, restoring, modifying, or testing his highly modified COZY aircraft when it was given to him. I respected his drive and dream, as well as his ability to sacrifice and work very hard. But listening to good advice and following it was not his strong suit. And now we talk about him in the past tense because of that.

[AVI]

The plans are woefully incomplete. As are the drawings, which are neither complete nor accurate. Anyone interested in Berkuts should spend a lot of time talking to James Redmon, who has what is in my opinion the most beautiful and well engineered Berkut on the planet, and who works on them (and other canards) in the Dallas area. He will tell you that you would have a hard enough time building a Berkut from a kit, much less ab-initio.

 

With respect to Zubair, whom I liked very much as a human being, he is currently the "late" Zubair Khan because he did not listen to good advice regarding building, restoring, modifying, or testing his highly modified COZY aircraft when it was given to him. I respected his drive and dream, as well as his ability to sacrifice and work very hard. But listening to good advice and following it was not his strong suit. And now we talk about him in the past tense because of that.

 

Marc,

Your comments about the late Zubair are unfortunately, extremely accurate. Listening to good advice and following it certainly was not his strong suit. RIP Zubair.

 

In reading up on both the Zone here and Canard Aviation, I personally have acquired immense respect for your vast knowledge and willingness to share it, but in regard to the Berkut drawings, let me ask you, have you personally reviewed the JG drawings? In other words, are your comments about the plans being woefully incomplete and inaccurate based on what you have been told by one of the "experts," or are your comments based on personal experience in examining and reviewing the drawings?

 

You see, I've been told the same thing about the drawings being woefully incomplete and rife with errors by James Redmon, but after purchasing the one hundred sheet set from John Griffiths, and reviewing them in detail, I've discovered this is not entirely true. Now, there's always the chance that what I don't know that I don't know I don't may pop up and bite me, but so far, this has been my experience.

 

The drawings were not originally meant to be a build manual in the manner of the Rutan LongEZ plans, so there definitely are certain details not included, especially details of the factory molded parts, but "woefully incomplete"? There are indeed a few minor inaccuracies, mainly due to the fact that the drawings were drafted manually with drawing board and T-square and not present day CAD, but I would certainly not categorize them as being "woefully incomplete ... neither complete nor accurate." The minor errors and inconsistencies are readily corrected when input to CAD.

 

It has been mentioned that the drawings alone are insufficient for a build without the addition of the manuals and the set of videos, but both the manuals and sets of videos are available, perhaps not readily available, but available just the same to a determined researcher.  And why, I ask, the availability of molded parts aside, would the construction of a Berkut be so much more difficult than a LongEZ or Cozy that you would so adamantly discourage the construction of one?  The wings and canard are basically LongEZ, so why would they be more difficult to build on a Berkut? This leaves the fuselage and RG, but there are LongEZs successfully flying with RG, and both LongEZs and Cozys can be found with highly modified fuselages.

 

It most certainly would require extensive research to put things together, but this has not prevented enthusiasts like Bob Setzer and Tony Malfa of Canard Gear from pursuing their goals.  Yes, I readily admit that it would add a great deal of time and not inconsiderable expense to a build a Berkut clone when compared to a "per plans" Cozy or LongEZ, but the fact that the Berkut was based on a LongEZ and wet layup CF/glass construction and not molded with prepreg and autoclaves like the Lancairs would make it a more appealing kit aircraft to reverse engineer, wouldn't it? Now, if you believe that my comments are way off base, and I'm somewhere in La-La Land, please don't hesitate let me know.  Just give me a few minutes to put on my flak jacket. 

[Marc Zeitlin]

are your comments about the plans being woefully incomplete and inaccurate based on what you have been told by one of the "experts," or are your comments based on personal experience in examining and reviewing the drawings?

The former. I've only taken a cursory look at the drawings.

 

You see, I've been told the same thing about the drawings being woefully incomplete and rife with errors by James Redmon, but after purchasing the one hundred sheet set from John Griffiths, and reviewing them in detail, I've discovered this is not entirely true. Now, there's always the chance that what I don't know that I don't know I don't may pop up and bite me, but so far, this has been my experience.

As I said, I haven't gone through the drawings in detail, and both I and James could be full of sh*t, but that seems unlikely. James has worked on MANY Berkuts, built at least a few, worked with Ronnenberg building Berkuts and Mobius's, and I've never known him to not know what he's talking about. I would suggest that a likely situation is that you don't know what you don't know (yet). But YMMV.

 

The drawings were not originally meant to be a build manual in the manner of the Rutan LongEZ plans, so there definitely are certain details not included, especially details of the factory molded parts, but "woefully incomplete"?

In the sense that you CANNOT build a plane from them - you can just use them for reference, IF you know what parts of them are not right. Which I don't.

 

There are indeed a few minor inaccuracies, mainly due to the fact that the drawings were drafted manually with drawing board and T-square and not present day CAD, but I would certainly not categorize them as being "woefully incomplete ... neither complete nor accurate." The minor errors and inconsistencies are readily corrected when input to CAD.

I wasn't talking about the technical quality of the drawings - as far as I can tell, they're done very well. But the technical content isn't complete. And that's not JG's fault - there was NEVER a complete definition of what a Berkut was, and even when they were built as a kit, every one was different, with different parts included.

 

It has been mentioned that the drawings alone are insufficient for a build without the addition of the manuals and the set of videos, but both the manuals and sets of videos are available, perhaps not readily available, but available just the same to a determined researcher.

Still not a complete definition of what the plane is or how to build it, in my understanding.

 

And why, I ask, the availability of molded parts aside, would the construction of a Berkut be so much more difficult than a LongEZ or Cozy that you would so adamantly discourage the construction of one?

Because reproducing molded parts without a mold is difficult - they're usually a different design. And re-creating molds, as Kent pointed out, is WAY more work than moldless construction.

 

Kent pointed out that few people that start building planes finish them. He estimated that 50% of COZY's don't get finished. That's WAY too optimistic - it's closer to 10% for the general population of plans built aircraft, and 20% for the COZY's. So if you've only got a 20% chance of finishing when there IS a complete set of plans, MANY examples from which to copy, a good support structure, and a full and relatively accurate drawing set, what do you think the completion rate will be when those things are NOT the case? I want to encourage people to start a project that I think they are equipped to finish - it does no-one any good to have a 1/4 finished "Berkut-ish" type of thing laying around in someone's garage.

 

The wings and canard are basically LongEZ, so why would they be more difficult to build on a Berkut?

They wouldn't be, as long as you don't try to emulate the molded versions, or build them out of carbon. As Magnum said, carbon should NOT be used with contact layups - if you're not going to bag a structural layup, don't put any carbon in it.

 

This leaves the fuselage and RG, but there are LongEZs successfully flying with RG, and both LongEZs and Cozys can be found with highly modified fuselages.

So if you build your airplane using Long-EZ or COZY techniques, but make it shaped like a Berkut, that's fine - as you say, it's been done a few times and works. The hard part would be trying to emulate the Berkut molded fuselage techniques (molded longerons, etc.) without Berkut molds. I have no problem with people modifying Long-EZ's to have a more rounded fuselage and nose, and, _IF_ they have a clue what they're doing, stretching the fuselage. Installing retracts is not rocket science either (although I'm not in any way, shape or form a fan of the Berkut landing gear - they have NO flex and rely totally on the tires for impact flexing during landings. A TERRIBLE design that could NEVER pass certification requirements).

 

It most certainly would require extensive research to put things together, but this has not prevented enthusiasts like Bob Setzer and Tony Malfa of Canard Gear from pursuing their goals.

With all due respect to both of those guys, who work very hard on what they're doing, in all the years they've been working, do either have a flying plane? Tony sells parts to other builders and claims they're better. Bob isn't selling anything.

 

At some point, you have to finish something and fly it to prove that what you're doing is possible and works. So far, this hasn't happened.

 

Now, if you believe that my comments are way off base, and I'm somewhere in La-La Land, please don't hesitate let me know.  Just give me a few minutes to put on my flak jacket. 

I think we're looking at this from two different viewpoints - not that you're nuts. You're saying that building a Berkut without the ability to purchase molded parts is possible with a lot of extra work, expense and research. And I agree - one could build something that looked pretty much like a Berkut and worked like a Berkut doing what you've stated. Possible - yes - absolutely.

 

But my position is that it's already difficult enough to build a plans built aircraft, without having to figure out what it is (or should be) and then how to emulate molded parts without molds. So to maximize the chances of finishing a plane, I'd recommend building one that's well defined, not one that isn't, and never was, even when kitted.

 

That's all I was trying to say - you've got a 20% chance of finishing a LE or COZY. Don't make that chance any smaller by choosing to make things far more difficult than they need to be :-).

 

If, for some reason, you think you want/need retracts, which is really the only advantage for very high power aircraft that the Berkut has over a Long-EZ) put retracts in a Long-EZ. But if you're not going to put an O-540 in your two-seat tandem canard aircraft, personally I think retracts are a minimal advantage, given the weight, expense, complexity and reliability issues. The rear opening canopy's are a nightmare - getting in and out is an incredible PITA, compared to a LE and if you have an  un-commanded canopy opening, you're losing your prop too (which then leads to much larger issues). The outward cant of the winglets gives them less advantageous yaw/roll coupling behavior, as well.

 

I'm not a big Berkut fan, although they are pretty. But "sexy" is not a sufficient reason to build a plane, although it's certainly a component. I've ridden in them and flown them. They're nice. But the extensive added work that you posit to attain one, IMO, is nowhere near worth it.

 

Anyway, My $0.02.

[Marc Zeitlin]

Jon - why in Cthulhu's name is there a maximum number of quoted text blocks that the forum allows (which my previous post exceeded, apparently by one, until I deleted one)? Seems pretty arbitrary...

[Jon Matcho]

Jon - why in Cthulhu's name is there a maximum number of quoted text blocks that the forum allows (which my previous post exceeded, apparently by one, until I deleted one)? Seems pretty arbitrary...

 

See attached for a screen snippet from the Administration console which mentions a reason.

 

That default was 10, which I just changed to 20.  The limit is not to prevent the typical style of quoting you're using, but prevent this business:

 

 

 

 

Quotes within quotes withing quotes...

 

 

 

Since 'quote embedding' is turned off when quoting posts, 20 won't cause any problems.

[AVI]

Ah, to a newcomer to this thread it would appear that the greyhounds are running around in circles chasing the proverbial mechanical rabbit.

 

I've come to the conclusion that it's senseless to debate the issue with line-by-line quotations and rebuttals ad nauseum.

 

It is surprising though, to find Marc Z who's usually the facts and performance figures policeman and a stickler for definitive information, facts and figures, nothing but the facts, Ma'am, spout off about the set of Berkut drawings as being woefully incomplete and inaccurate after admitting to having taken but a cursory glance at the drawings. I'm disappointed.

 

If you'll scroll back a few posts you'll find that I have not recommended that anybody run out, order materials and begin the immediate construction of a Berkut. In fact, you'll red that I actually recommended against it and attempted to dissuade Sohail, who was asking whether there was sufficient information in the drawings for the construction of a fuselage,  from attempting to build a Berkut, recommending a LongEZ instead.

 

The discussion was about whether the drawings contained sufficient detail and information, and my humble opinion, after detailed examination of the drawings, was that it was indeed possible but would perhaps involve the expensive and time consuming construction of a plug and molds from which to pull the fuselage shells.

 

We also mentioned the lack of longeron specific drawings, but in reality, there is sufficient detail contained in the drawings for a builder to develop the shape and size of the longerons, if, once again, the builder were inclined to mold them.

 

As for the merits of some of the features of the Berkut, well, the debate regarding rear hinged canopies has been well documented, as are the weaknesses of the Berkut landing gear. There has even been mention of Berkut builders regretting the installation of the larger engines. There's been a lot written about the Berkut. Some great, accurate  information, some bordering on gross misinformation.

 

Research? Well, doesn't research also apply to the construction of present day LongEZs? Information, including the plans and templates are readily available but do require a great deal of research. As for no two Berkuts being completely alike, doesn't that also apply to many modern day LongEZs? How many are built strictly to the 1980 plans without a single modification? Probably not a single one.

 

I'm not advocating the revival of the Berkut design - the potential purchase of the company was recently discussed on another forum - I'm not recommending that anybody attempt to build one.  I'm simply stating that the John Griffiths' drawings which were not intended to be a build manual, are not rife with inaccuracies and woefully incomplete.

 

I also continue to maintain that there is sufficient information, detailed and accurate information, contained within the drawings and the build manuals for a determined builder to build a Berkut, which in fact is basically a stretched LongEZ with retractable landing gear. Now, whether anybody would choose to build one is a different matter, but that's well within the spirit of experimental aviation.

[Marc Zeitlin]

It is surprising though, to find Marc Z who's usually the facts and performance figures policeman and a stickler for definitive information, facts and figures, nothing but the facts, Ma'am, spout off about the set of Berkut drawings as being woefully incomplete and inaccurate after admitting to having taken but a cursory glance at the drawings. I'm disappointed.

All I'll say to that is that I trust James Redmon's opinions and statements implicitly. If anyone other than Dave Ronnenberg knows Berkuts, it's James, and I repeated what he told me. I will trust someone who's built numerous Berkuts and worked for the company that built them over folks that have built none.

 

IMO, as always.