Welcome to the Canard Zone!
Check out our new setup and let us know what you think. Here are a few tips and shortcuts to help you on your way:
- Sign up so you can join the discussion! See below for the most recent posts across all sub-forums.
- Feel free to start a new topic or just introduce yourself. We appreciate the company!
- Personalize your account by clicking your username in the upper-right area of the page.
- Don't like ads? Just sign in and you are ad-free!
- Visit us using your mobile device or tablet -- the 'Zone is mobile-friendly.
Thank you for visiting -- we are looking forward to hearing from you!
This EZ today on B-stormers N4884Y https://registry.faa.gov/AircraftInquiry/NNum_results.aspx?NNumbertxt=4884Y Resonably priced for the nice panel, I would say (unless the engine is run-out)
LONGEZ • $33,500 • FOR SALE • Nice IFR equipped LongEZ. See inventory. 145 knots on less than 6 gph. Only selling because of another aircraft purchase. Will deliver with new annual condition inspection. Prefer initial contact via text to #703. • Contact Fred Wimberly, Owner - located Callao, VA United States • Telephone: 703-409-5330 • 804-529-5753 • Posted July 19, 2019
If you know of a canard aircraft that will be for sale at Oshkosh or see one for sale there then please post the details here - I'm shopping!
Jon Matcho 541 hour ago, Kent Ashton said:
Ya know, we are both guilty of saying "I recall XXX" or "I remember saying someone said XXX". This is lazy. We should strive to document what we're saying.
Agreed. There's just so much time in the day and the pros/cons of foam/fiberglass vs. ribs/carbon are beyond RSD's original question:6 hours ago, RSD said:
How were the Berkut's wings constructed - fibreglass over foam like a long-EZ or another method?
You and I both answered the question the best we could (original Berkuts had foam-core wings, and later used a rib structure).
However, your link to Wikipedia is still just text without a citation; essentially hearsay anyway. So... there's more work to do in order to back up our claims, but at this point that's all I've got. 🙂
1 hour ago, Jon Matcho said:
I recall reading that the first Berkut wings were carbon skins on foam cores, and then they later replaced the foam cores with carbon ribs.
I recall reading the same thing somewhere on the 'net, and recall discussing while flying in Marc Zeitlin's Cozy IV. Marc pointed out the flex of the wing, and that we were not feeling it much in flight. If it were carbon, we'd be feeling it.
Ya know, we are both guilty of saying "I recall XXX" or "I remember saying someone said XXX". This is lazy. We should strive to document what we're saying. Here is a comment about the ride from http://www.airbum.com/pireps/PirepBerkut.htmlQuote
The extreme stiffness of the airframe was very noticeable when cutting through turbulence. Since we were whistling along at over 200 mph and nothing in the airframe was flexing to absorb energy, even moderate chop hammered at us with sharp edges.
and about the construction of the wings from https://en.wikipedia.org/wiki/Berkut_360Quote
Early Berkuts used wings and canard that were structurally similar to the Long-EZ and used solid blue 2 lb/cu. ft. density Dow STYROFOAM PI cores cut to shape with a hot-wire foam cutter, but with carbon fiber reinforced polymer skins instead of fiberglass. The fuselage and winglets remained fiberglass. Later versions (kits produced after spring 1999) used fully molded carbon fiber canards and wings with high density, 5 lb/cu. ft. 1/4" thick PVC or SAN foam cores, leaving only minor fairings and tip surfaces to be carved from foam. The Berkut has always used the Roncz 1145MS canard airfoil, which is more tolerant of insect and rain contamination than the GU 25-5(11)8 airfoil originally used on the Long-EZ.
This kit was sold with "molded wings (including flat stock for ribs and spars)" so I you seem to be correct about the wing with ribs. https://www.canardzone.com/forums/topic/17030-berkut-project-for-sale/
I don't know if Berkuts were ever built with Long-ez spec wings but there is plenty of discussion about Berkuts found with a google search.
Visit the forums for more!
There's a long history with ongoing discussion about new and coming (and gone) canard aircraft that have been in the works over the years. This thread makes for some interested reading and lessons to be learned.
Here's how I built a couple of props. The first one was good right out of the box--credit beginner's luck. The second one which I will discuss here took a lot of adjusting; you might find it interesting. At the outset, I will admit that it's easier to just buy a prop but what fun is that! There are probably easier ways to draw prop blades with a 3D CAD program but this is was my method.
1. The first thing is to decide what length and pitch to build. I kept a list of props I read about that a people were using with a given HP and speed range and put them on a spreadsheet. (pic 1) Comparing pitch is tricky because a prop builder might be quoting the pitch of the flat side or the pitch of the prop's chord line. There can be several degrees difference. I just assumed that every pitch was quoted at the chord line.
2. Pitch is quoted in inches at the 75% station. It is the geometric distance a prop with no slippage will advance forward in one rotation. However, a builder must know the chord pitch angle. My spreadsheet converted pitch-inches into a pitch angle. I chose 26.8° chord pitch angle for my 180 hp engine and a 67“ length. From some previous experimenting, I believe length is not too critical. Pitch and tip thinness make a big difference.
3. I used six nice maple boards, 3/4” thick, so the hub thickness would be 4.5”. I scraped them as recommended to open the pores and glued them together with Weldwood Plastic Resin glue, rolling glue on both surfaces and flipping the growth rings for each board, and clamped them tight for a couple of days. (pic 2) The Weldwood product was recommended because it has a more generous working time than Resorcinol.
Your correspondent in Concord N.C. reporting:
I have always been a little suspicious of the plans Long-EZ engine mounting points. No good reason, really. If you use 4130 angles or thicker 2024 angles in the firewall, it seems to hold up fine in service, so no need to do anything much different.
However, I built a Cozy IV and like the way Nat re-designed the engine mounts in the C-IV so I thought I would go that direction. I got a good deal on an 0-320-H2AD. There is no mount or dynafocal ring made that would work, AFAICT--so I bought a dynafocal cup set from ACS to make my own dynafocal ring. Surprise! I thought the cups would come welded-up but you only get the steel--three pieces for each cup--and have to weld them to make the cups. Not too hard to do, though.
I had to start by machining some aluminum substitutes for the dynafocal doughnuts to postion the cups in the correct position. (BTW, a compressed dynafocal doughnut and cup is 2" thick) After that it was a solid 4-5 days of work for me. Goes like that when you have to re-sharpen about a hundred tungstens, find your misplaced spectacles, etc. Seems like I ought to have more tubes but compare it to a C-IV mount from the Cozygirrrls. Mine looks at least as robust as Nat's design which is holding up well. I might add another cross brace at the bottom.
Here are three pics of my mount with the alum spacers I made, a regulation C-IV mount from the Cozygirrrls, and a mount from the internet that might have been for an O-540. That one is stout.