Marc Zeitlin

Welcome, John. I don't want to pick on you (because I've seen many cases where someone purchased an airplane thinking they would be able to mold it into what they wanted and weren't able to do so), but this is where I'll throw in my plug for a reputable Pre-Buy examination from one of a number of canard experts who have seen, worked on and inspected many canard aircraft - not just the one they built. It can save you (the generic you) a lot of heartache down the road. Particularly with weight - it's almost impossible to take weight out of a plane unless there's something very obvious, like big metal accessories that aren't required, or that can be substantially reduced in size. And you can. Even a heavy Long-EZ may be a fine plane, as long as you don't want to carry another person and much fuel at the same time. Depending upon engine, many Long-EZ's use 1600 lb as the MGW, rather than the book value of 1325 lb. This reduces the size of the V-N diagram and maximum "G" load (as well as maximum landing vertical velocity), but hardly makes the plane a basket case or unusable. Depending upon your engine and empty weight, this might still be a perfectly useful plane for 90% of your missions. Yeah, well, all I can say to that is that even the Pope is only infallible in a very specific set of circumstances. No one's written (or oral) guidance should be accepted as divine truth, least of all mine. Are some folks right most of the time? Sure. But verification and validation, or at least asking for explanations of WHY someone holds the position they do, is necessary. Let's figure out how to make your plane as usable as possible.

Here are a couple. This is a VERY simple diffuser - not 7 degree angles, and not very wide. It's got cutouts for hoses, throttle cable, and air filter, and yet, up to 13% more pressure at the oil cooler - never measured the pressure across the cylinders (as my CHT's were always fine).

I won't comment on the shown diffuser, but I will say that when I added a NACA diffuser, similar to that shown, to my cowl, I increased the pressure drop accross my oil cooler by anywhere from 5% to 13%, depending upon IAS.

On an updraft cooled engine, if you put the distribution block and the FI lines on the top, they tend to get hot and cause vapor lock and very hard starting, as well as poor running when hot at low RPM/fuel flow. I've had customers have noticeably better engine running after installing insulation on the FI lines when they're on top of the engine. If you install the DB and FI lines on the bottom, as is recommended for updraft cooling, those issues don't exist (at least any more than they ever do on mechanical FI lycomings).

I figured that since you knew that COZY's were using it, and mentioned that, that the solution was clear. I didn't think it was necessary to point out that if 800 COZY's had been built with something, it was probably OK to use.

You guys are wasting an awful lot of time and effort on this. Just use P/N 01-14400 Last-A-Foam from ACS for the bulkheads in question (IP and a couple others) and call it a day. Cheaper and available without any special ordering.

Any of the approved epoxies are by definition "strong enough" and "recommended". I do not know anyone who USED the 105/209 combination to build a plane, but it is an approved combination. Personally, I'd use the MGS or Pro-Set (and have used them both on projects), with the EZ10-87 for anything that touches fuel. But they all work.

This is an incorrect interpretation of reality. "WEST Systems" is a brand name. The 105 is the resin, and 205 / 206 / 207 / 209 are the hardeners. Only the 209 hardener, in concert with the 105 resin, is approved for structural layups - the 205/206 hardeners are great for micro/finishing.

Smaller and infinitely more comfortable. I sit in a C-172 and after 2 hours, I'm miserable and my butt hurts. After 5 hours in a COZY MKIV, I'm fine.

Folks: I've downloaded Russ' recording of last Friday's Zoom presentation about my electrical system and IP. I've put it up on Dropbox at: which is also the directory that holds all the IP and interior pictures, as well as the documentation of the electrical system. The video is BIG - almost 1 GB.

There are a few COZY's, Berkuts and other canards flying with CS props. I'd guess less than 1% of the total. Those that have them generally say that they help with takeoff/climb, particularly with O-540 powered aircraft, but either hurt or do nothing on the top end. I always recommend NOT using CS props, due to the cost, weight, maintenance issues, etc. unless you have a VERY particular set of circumstances that requires it. Which fewer than 1% of folks do. Nat invented weight limits to protect people from being stupid(er than they already are). There is no 400 lb. front seat weight limit, or 300 lb. rear seat weight limit that's determined by structural limitations. If the people can fit (and THAT'S the limiting factor almost all the time) AND you're within the MGW and CG limits, you're good to go. MGW for any E-AB aircraft is whatever the manufacturer (you) say it is. In Phase I, you're required to test to whatever limit you set. If you set your limit higher than the designer specified, you better understand what limitations that puts on takeoff performance, "G" loading, and landing vertical velocities (amongst many other things). On Long-EZ's, people extend the nose a bit to fit a battery for CG reasons when they install an O-320 instead of an O-235. They extend the nose a lot when they don't have a clue what they're doing and think that they're making the airplane look better. In a COZY MKIV, there's exactly zero reason to extend the nose, although a few folks have done it (again, for aesthetics). Eh. Closer to $30K, at this point, if not more, given shipping costs. Maybe if you're a great scrounge and buy in bulk you could do it for under $30K. Plan on $30K - $40K by the time you get through with it, and if you do better, congratulate yourself.

2990 from start to first flight for me. Nat said 2500 hours - most of the folks I talk to say 3K - 3500, give or take. 4K would be conservative unless you're making a bunch of non-documented mods, IMO. There are a few folks that have done it in less that 2K hours, but I think they used a bunch of prefab parts that others made for them.

They're not. But there are 5 lb. cowls, and there are 20 lb. cowls, even with cloth. I don't even want to guess what they'd weigh out of chopped rovings. No one makes cowls from anything but cloth, and some use carbon and fiberglass to minimize weight. It's an airplane, not a Corvette body.

Yes. No. Unless you don't give a crap how heavy your cowls are.

Hopefully, the pilot still has a head, though, and the back seater can't see through that. The lack of headrest will help forward visibility a bit for the rear seater, but in tandem planes, rear seat visibility forward isn't great. Every other direction is great, though. Yeah, I can see the pants on the plane, but they're the old football style - Tim's goal was to put the newer pressure recovery style wheel pants on the plane and pick up a few kts. I've got them sitting in my hangar... Either convince Tim to bring the plane to KTSP for a Pre-Buy, or pay for me (or someone else competent) to go to Phoenix to spend a day examining the plane. See my website (in the signature) for my services. There are a couple of other folks I can recommend for PB's as well.

That canopy will have exactly the same forward visibility as the standard one part canopy. It will make it harder to get in and out of the plane (which is bad), and will have less "bowing" with temperature changes (which is good). There is zero rollover protection from the headrest (it's a headrest, not a roll bar), so nothing is lost other than a headrest. _IF_ the existing canopy hoop was constructed well, possibly per Mike Melvill's instructions on installing a rollover hoop into the canopy, it will be better than nothing, and possibly better than the original headrest. It's a PITA, but with composite aircraft, everything is doable. A far more reasonable solution would just be to polish them, using something like one of these: https://www.aircraftspruce.com/categories/building_materials/bm/menus/cs/windshieldrestoration.html No. Compressions are almost meaningless - upper 60's are fine, 70's are fine, 45 is fine, _IF_ the engine is making rated power, not using oil, and not making metal. Far more important is a borescoping. I suggest reading Mike Busch on compression testing. I've seen engines read 30, then 77 after a 10 minute run (and need a rebuild), and others that read 45 measured hot after a couple of flights and was perfectly fine for hundreds of hours afterwards. Compressions are a HINT that MAYBE something's going on, or not, but they're hardly the last word. People make WAY too much of compression checks. This plane has flown an average of 11 hours/year SMOH. That's almost always a bad sign for engines - just enough time to let the moisture build up, the corrosion start, and the little bit of running to beat the crap out of it. BUT, if it's lived the whole time in the desert, then the chance of corrosion is pretty low. Pulling a jug would tell, BUT (again, per Mike Busch) has its own risks and costs associated with it. Since it's a rarely used plane, I'd probably want a local A&P who's NEVER SEEN THE PLANE BEFORE to CAREFULLY pull a jug and borescope the cams and lifters. What you ACTUALLY need is a real Pre-Buy examination along with the engine check - none of that will be cheap. This MIGHT be a decent, albeit slightly overpriced plane given the panel, or it might be a $20K - $25K plane that needs a new engine. Strangely enough, I was scheduled to install wheel pants on that plane here in KTSP until weather and COVID got in the way - not sure what the plan is now. Nope. All easily fixable in an afternoon, even if there is a slight fuel leak around the drains.

Well, actually, if you go to the second link and search for "Rotorway", there are five approved designators depending upon which Rotorway model it is - no need for the "ZZZZ". But you're correct that ATC doesn't give a crap about what the FAA's database says the plane is, as long as you call it the right thing when you talk to them. Now, being somewhat obsessive, _I'd_ want to correct the wrong information in the database, and I'd ask the current owner to do so before I bought it - they could contact their local FSDO to get instructions on how to change the incorrect information (and there's no "major change" involved - you're only changing data in the database - you're not actually changing the aircraft). If the owner doesn't want to, since the helicopter's been flying just fine for 15 years with incorrect info in the database (which could be an issue for the insurance company, since THAT's the info they use to determine how much they're going to charge you), you can always make the corrections yourself after you buy the thing. The FAA isn't going to argue with you about it - you just have to fill in and submit the right forms.

Easier to "use", yes. Please provide evidence of FADEC piston engines being more fuel efficient than a manually adjusted fuel injection engine. Thanks.

For aircraft plans sold by companies no longer in business and for which no copyright owner can be found (or who has given up the rights to the copyright), have at it. For the COZY MKIV, owned and sold by ACS, you're restricted to the agreement you sign with them. Al neither has nor needs permission, since he's not selling COZY MKIV plans, but only parts. Only the plans are copyrighted - nothing in any of these planes is patented.

Give me a clue what "fuel leak issue" you're talking about. No and no. MAYBE using some fuel cell foam in the tanks might be useful, but given the relative paucity of evidence of fuel tank fires (the few canard aircraft fires have been engine compartment fires, not tank fires in the air or on the ground, and there have been no "explosions") there's no evident issue with the construction of these aircraft's fuel tanks. Posting a reference to what you're talking about will help others respond in a useful manner, rather than having to guess what you're talking about.

Kent buried the lede :-). If you're building a COZY MKIV, you should join the COZY mailing list at: http://cozybuilders.org/mail_list/ read through the whole http://cozybuilders.org/ website, as well as all the links that Kent pointed you to, particularly Wayne Hicks'. Then read through all the presentations at: http://cozybuilders.org/Oshkosh_Presentations/index.htm many of which will be repetitive, but there's a LOT of what you asked there. Plan on changing as little as possible, within reason, unless you're interested in having your kids be fully grown before you fly it :-).

Were you to bring that plane to me for a Condition Inspection and we found that crack in the bracket, there is no way I would sign off the CI, which says that the aircraft is "In a Condition for Safe Flight". Were I to see that crack on a Pre-Buy examination, I'd tell the buyer not to purchase the plane until it was fixed, or ensure that the plane was trucked to a place where it could be fixed. I'd tell the seller not to fly the plane until it was fixed - maybe ONE flight to the place of repair, but that's it. Landing gear collapse, which is what a failure of that bracket could lead to (however unlikely it may be, and given the crack, it's not ALL that unlikely) can be a catastrophic event. Land hard, hit a small pothole, etc...

That's a Hertzler prop.

Well, I wouldn't say "obsolete", as Kent says - just sub-optimal. Thousands of canards have the old plain bushing style NG-6, and if installed correctly and adjusted on occasion, they work fine. Tapered roller bearing is better, but expensive. Pays your $$$ and takes your choice. Agreed - a close-up of the pic you posted shows a raw nose gear strut with no torsional wraps - you can't see any weave; it's shiny; and there's no peel ply texture. This is a clear indication, in my opinion, of the intensely sub-standard and unsafe work that Mr. Hanson continuously cranks out. That said, the nose gear strut is <$100 from Aerocomposites, and the upper and lower castings, as well as the NG-3/4 are easily salvageable. Heat and a hammer will break them free of the strut, and you can grind out the residue. Or just grind the strut out of the castings, since you're not trying to save the strut. Actually, for bonding, JB Weld is probably superior to flox in a laminating epoxy - the bonding strength is higher. No one in the industry uses laminating epoxies for bonding - various Hysols are common bonding agents, and JB Weld is in type of family. So that was the least of the issues with the nose strut assembly - really, the only issue was that the strut wasn't wrapped - if it had been, you could have easily lived with the JB Weld and older style NG-6.

No, that's not at all what I'm saying. You have a horizontal surface relationship to CG that needs to be maintained (CG forward of Aerodynamic Center) in order to have static longitudinal stability. However it can't be TOO far forward, or else the airplane becomes unable to rotate for takeoff, and TOO stable in pitch to the point that you lose maneuverability. You also need to have an equivalent vertical surface relationship to the CG in order to have lateral stability. Read up on aircraft stability requirements and calculations. Moving CG forward might address the lateral stability issue, but completely screw up the ability of the aircraft to get off the ground and be maneuverable once it does. Everything is a balance, but having as much vertical area at or forward of the CG position (about where the pilot is going to be in one of these planes) is going to make the plane want to fly sideways or backwards, or at least be happy to do so if it happens to be perturbed in that direction. I suggest googling "aircraft design book" and purchasing a number of the ones that come up - Raymer's is good, as is Roskam, just for starters. Also "Perkins and Hage" for "Stability and Control". You cannot design anything other than a standard looking aircraft (think C-172 or Piper Warrior) using "that looks about right" techniques. Particularly with canards and/or tandem wing aircraft.