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Marc Zeitlin

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Marc Zeitlin last won the day on March 6

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About Marc Zeitlin

  • Birthday 08/06/1957

Flying Information

  • Flying Status
    Flying - 1966 hrs.
  • Registration Number
    N83MZ
  • Airport Base
    KTSP

Personal Information

  • Real Name (Public)
    Marc J. Zeitlin
  • Location (Public)
    Tehachapi, CA 93561
  • Occupation
    Principal - Burnside Aerospace
  • Bio
    www.mdzeitlin.com/Marc/bio.html

Project/Build Information

  • Plane Type
    Cozy Mark IV
  • Plane (Other/Details)
    COZY MKIV
  • Plans/Kit Number
    386

Contact Methods

  • City
    Tehachapi
  • State/Province
    CA
  • Country
    United States
  • Email (Visible)
    marc_zeitlin@alum.mit.edu
  • Phone Number
    978-502-5251
  • Website URL
    http://www.cozybuilders.org/

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  1. A review of the POH and the documentation for the plane would have been one of the first items on my Pre-Buy checklist prior to purchasing an aircraft. But to each their own, I suppose. Planes are weighed with no fuel aboard. The VE POH sample W&B indicates an expected empty weight of 535 lb. No VE on the planet has ever weighed less than 600 lb., to my knowledge. The lightest one I've ever heard of is Joe Person's plane, at 610 lb. (Day VFR, no starter). Now, most of the VEs I inspect and work on weight between 680 lb. and 750 lb. A 750 lb. VE is a total pig. Anything over 700 lb. is pretty heavy. If you're near 650 lb., be VERY happy. With a POH MGW of 1050 lb. (1110 lb. under certain conditions) you can see that anything over a 700 lb. VE isn't going to be able to carry much more than the pilot and full fuel. Also be sure that you know whether you've got the long or short canard and which CG range that implies. To the extent possible (which isn't much, for such a safety critical component), inspect the wing attach fittings for corrosion. Ensure you're familiar with the wing attach fitting corrosion issues that are well known and documented on Variezes. Have (and review) all the CP's, mandatory changes, and wing fitting corrosion warning documentation. Be aware of the concomitant "G" loading restrictions. mandated by RAF, as indicated in the wing fitting corrosion documentation.
  2. Belcranks and pulleys take approximately zero maintenance. 15 seconds at the CI to make sure they're still attached, and never lubricated, since they have sealed bearings. The fact that people have installed these tubing guides does not imply that they were fixing a problem. Never seen them and can't imagine why they would be required.
  3. Friction isn't the issue - wear is (or MIGHT be). If you can find something that doesn't get worn by SS cable (and in turn, doesn't wear the cable, which is just as bad), then that might be a good liner. Or you might be fine with a 20 year lifetime and a note in the logs that after 20 years, it's time to replace the cable and the guide. Don't know. AL/SS tubing would still need to be fixed securely at both ends. One plane that I've worked on for the past 11 years has AL tubing as a guide, and every couple of years we've got to re-bend and secure it, as rudder throw continually gets lower and lower over time. Fix it well at both ends and this problem goes away.
  4. Folks have done similar installs with either nylaflow or AL tubing. It can work, but there are a couple of possible issues, one of which I've seen multiple times. First, the SS cable will wear the tubing as it goes around the bend. How long with the tubing last? Hard to say. I suppose it depends on how much and how hard you use the rudders at speed. Nylaflow DOES wear - I've seen it worn through at the exit to the belhorn at the winglet, where it wears a groove in the nylaflow. But a totally enclosed tube is less prone to wear. AL will wear as well, but it might take 10 years or it might take 1000 years. Secondly, and this is the issue I have seen, is that unless the tubing is extremely rigidly mounted where it passes through the firewall and where the SS cable exits to go to the wing, it will flex and you will lose rudder deflection motion. And the rigid mounts need to allow for tubing replacement in case of damage to either the cable or the tubing. My $0.02.
  5. The intercylinder baffles top and bottom are there to force the air through the cooling fins, rather than being able to avoid them. Some folks have them, some don't - it's not obvious that they either help or hurt, as there are so many factors that affect cooling that it's difficult to tease out a single factor. I have them and my CHTs run fairly low. If they were there before, and your temperatures were decent, I'd leave them in.
  6. Well, sure - you don't NEED the aircraft/engine logs, but they're extremely useful in telling you about the care that the builder/owner may or may not have taken with the plane, and what's happened to it. Legally, they're meaningless after 1 year, but no logs is a yellow flag, if not a red one. The AC on this plane is valid - only the registration would have to be changed to the name of the new owner.
  7. The barnstormers ad says that the logbooks have been found. Don't know if they mean build logs or aircraft/engine logs. An engine that has sat for 16 years, if not pickled (and probably even if pickled) WILL need a full overhaul. It might run for a short time before the MOH, but it'll still need one for all the soft components that age even when not used. Without seeing the plane in person, it is completely impossible to judge whether the price is right, low, or high. It could be a steal, or it could be too expensive if they gave it to you. You need a canard knowledgeable examiner for the PB - one who's seen a LOT of canards, not just the one they built or own. In the other thread, I recommended FFC - I'd talk to them first. A guy who works on jets (not even piston planes), however nice of a guy and amenable to inspecting an E-AB canard piston pusher, isn't going to have a clue what he's looking at.
  8. Kent gave some good feedback above. The builder's resume' means diddly squat. I've seen crap built by people that had amazing resume's, and excellent work by folks that were gas station attendants. Is it POSSIBLE that he did something that would increase the MGW and keep the structural safety factors per plans? Sure. it's POSSIBLE. But extremely unlikely, and unless you had documentation of it in the build records, you can't assume it. As I previously said, folks DO fly these planes overweight (per the designer's POH) regularly, and THEY NEVER STRUCTURALLY FAIL. Let's go through some rough handwaving as to structural strength... The Long-EZ was a 5G plane at 1325 lb. MGW. The COZY III is essentially structurally identical to the Long-EZ, so at 1500 lb. (POH MGW) would be, purely by ratio, a 4.4G plane. But Nat was conservative and said 3.8G. Continuing the ratioing from the Long-EZ, at 2000 lb., the COZY III would be a 3.3G plane. Now, Burt probably had at least a safety factor of 2X on the structure - some think it was closer to 3X, but we'll be conservative and use 2X, since that's usually what's used for composite structures. Which means that one would not expect a COZY III to fail until reaching 6.6G. Limiting it to the Normal Category 3.8G gives a safety factor of 1.7X - below 2X, but above the metal SF of 1.5X. The issue here is that there's a lot of variability in build quality - a perfect build might withstand 3X the limit load of 3.8G, while a crappy build might be a LOT less. And there's no way to know without test data from Phase I whether the plane was ever tested to 3.8G when loaded to 2K lb. Also, as stated this is a lot of handwaving, and while the wings/canard/main spar are almost certainly never going to fail unless you do something amazingly stupid in the plane (none ever have failed, in any VE, LE or COZY of any type - you're not going to lose a wing), overloading the landing gear on a VE/LE/COZY III is a recipe for required repairs down the road (could be next year, could be 20 years from now - also dependent upon original build quality and number of hard landings and pothole taxiing). So I can't say it's fine to load a COZY III to 2K lb. You're not going to fail in the air. But you'll beat the crap out of the landing gear. As Kent said, you need to examine the W&B very carefully to understand the maximum load for the front seat (Nat weighed about 140 lb. soaking wet) - many COZY III's are in the 340 - 360 lb. range so you'd only be able to take very small people with you. And even if you do only want to take small folks, you'd be operating at the forward end of the CG range, so would need longer runways, faster takeoff/landing speeds, and you'd cruise slower. I'm not trying to discourage you from buying the plane - if you're going to fly solo 95% of the time and can put all the extra weight you're going to carry in the back seat, where it doesn't move CG forward, it could be fine. But you should understand all of the ramifications. There's a reason these planes are called "COZY", not "ROOMY".
  9. Then he will be useless for everything except POSSIBLY the engine examination, _IF_ he knows something about piston engines along with jets. He might be exactly the opposite of what you're looking for. The fact that someone wrote a number in a logbook does not make it a safe #. The COZY III was originally designed as a 1500 lb. MGW aircraft, with an allowance to go to 1600 lb. for takeoff. The V/N diagram in the POH shows that it's a 3.8G aircraft at that weight (I assume, 1500 lb., not 1600 lb.). The fact that someone SAYS that you can load it to 2000 lb. is utterly meaningless. A VERY ROUGH handwaving comparison will indicate that if the plane is a 3.8G plane at 1500 lb, then it would be a 2.8G plane at 2000 lb. While 2.8G gusts are not common, they're not unknown, either. And your Va (maneuvering speed) with a 2.8G limit drops precipitously as well, as does Vb (gust penetration speed). If the plane weighs 1069 (which will be suspect until you do your own W&B) and you weigh 240, that's 1309 lb. Add 40 gallons of fuel (240 lb) and you're at 1549 lb - above standard MGW and barely below the max takeoff weight allowed by the POH of 1600 lb. Add some baggage and you're at 1600 lb., and you've got yourself a heavy single seater. Add another 200 lb. person and you're at 1800 lb. Now, do folks fly COZY III's at 1600 - 1800 lb, fairly regularly? Yes. Are most canard overweight? Yes. Have any failed structurally due to this? No. Does that mean that one can be cavalier about ignoring POH weight restrictions without understanding all of the ramifications of flying overweight? No. Are there other folks that weigh 240 lb that fly 1100 lb. COZY III's fairly regularly, sometimes with a 2nd person and baggage? Yes. But you need to understand what it all means and how all the parts play together. Get someone familiar with canard composite construction to look at the plane. There are a zillion of them in the Denver area and if you were on the COBA mailing list, it would take all of about 5 minutes to find them. Keep trying FFC as well.
  10. Who is Mike Cronk, and what are his bona fides? If a COZY III actually weighs 900 lb, that's a pretty light COZY III. I'm skeptical.
  11. While FFC is still at Meadowlake airport (KFLY) it's been owned by Ryan Goodman for a number of years now - Burrall retired a while back.
  12. Be very careful with making the mass balance longer - you still need to ensure that you can get full book value of TE down elevator deflection, but if the MB hits the inner upper skin too early, you can't.
  13. That is guaranteed, because the information presented about the plane is not even enough to start evaluating the condition of the plane as a whole, much less the engine, IP or wing attach fittings. The default answer on VEs is "no - stay away" unless the provenance and history of the plane is completely understood.
  14. This is what I wrote in the Pre-Buy examination residual report for the plane, back on March 27th, 2023: "Aileron Clearances - both are slightly tight to fuselage - clearance as for the elevator if the ailerons are ever removed" Apparently, the changing temperature/humidity caused some growth in dimensions (or there is some crap caught) which is causing the ailerons to rub. Now's the time to remove the ailerons and increase the clearance, which should be 0.062 - 0.1". Dirt/grime should not be able to cause control system binding. Fix it before the next flight.
  15. See 14 CFR Parts 45.21 - 45.33. All the registration marking requirements are there. Of course, about 1/2 the planes I examine don't meet the FAR requirements, and other than for international flight, I've never heard of anyone getting their wrist slapped because of it, but those are the rules.
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