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Marc Zeitlin

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Everything posted by Marc Zeitlin

  1. Marc Zeitlin

    Re-do... part 2

    That's not a vortilon, it's a drooped leading edge. It was an early standard modification to the plane to help with the aerodynamics that was later replaced by the standard three vortilons on each wing that you see on the LE of most VE's and Long-EZ's. It worked, but the vortilons were a lot easier to fabricate and install. I'd suggest reading the plans completely and then reading through all the CP's completely at least three times, then reading all the CSA newsletters, too. That' way, you'll know what you're looking at...
  2. Marc Zeitlin

    Re-do... part 2

    I disagree. It looks to me as though there are multiple spots on the left gear leg that are crushed, down near the axle and up about 2/3 way. Hard to tell from a pic, at least with regard to the top (without closeups), but the bottom - that looks like substantial damage. Also, it looks like something is going on on the bottom of the strut near the TE, but from this pic, it's impossible to tell what. And if the gear leg is damaged from a hard landing, the chances are good that the fuselage attach points are also compromised - you'll need to jack the plane up and push/pull fore/aft on the wheels to check for relative motion at the attach points. Any motion more than 1/16" - 1/8" fore/aft at the axle means some damage at the attach points. Anything more than 1/8" and I begin to recommend repairs.
  3. Marc Zeitlin

    Sales I've seen

    With any pusher aircraft that has a CAP (Complete Aircraft Parachute), that concern exists. But many pushers (particularly light aircraft) have CAP's, and have been tested. BRS designs their lanyards to be able to withstand getting caught in the prop, but the recommendation is to shut off the engine prior to pulling the chute. What would actually happen in any particular incident? No one has a clue. This customer (and the Berkut customer for whom I also worked with FFC to install a BRS) did a lot of night flight over rough terrain, as well as IFR and night IFR over rough terrain. They felt that in those cases, coming straight down slowly would be safer than any type of flight into terrain, even if the plane was completely under control.
  4. Marc Zeitlin

    Sales I've seen

    The top of the turtleback was thinned so that the rocket could blast a hole - BRS gives recommendations for what it can get through. The red tube is the attach point for the forward lanyards, and the rear lanyards attach to the top interior engine mounts. Let's hope we never have to find out if it would work, because we obviously never tested it. There was substantial modification to the fuselage sides to take the deceleration loads, which BRS states can get to 9G's.
  5. Marc Zeitlin

    Sales I've seen

    I did the engineering for that chute install, and Burrall did the install. Interesting that it's for sale just a few years later.
  6. Marc Zeitlin

    Open-Ez wing spar-cap thickness (thicker than a Long?)

    Your point 1) above is exactly incorrect. It's MOST important to cut the cap troughs to the right dimensions and then fill them to the top with fiberglass, however many plies it takes. Since the tape thickness has varied substantially over the years, the overall thickness of the cap is what matters, not how many plies one put down to get there. The ONLY thing that matters is correct trough depth. Point 2) is correct, but apparently Cameron believes that they are not identical. I don't have either OE or LE "M" drawings/templates, so I can't settle this debate.
  7. Marc Zeitlin

    Who are you?

    Yes.
  8. Marc Zeitlin

    Engine out landings

    So I generally chop the power about midfield downwind, so all of my landings are "engine out", with idle thrust only. About 90% of the time I don't have to add power. My MO is to always be high and have a lot of excess energy - it's easy to get rid of with LB, rudders and slips. The accident you reference was a COZY MKIV (N795DB), not a Velocity, and the judgement errors there were many. Poor fuel management, WAY too wide on downwind, and trying to stretch the glide when a perfectly good field was right there - I think that it was way more than "possibly". Along with engineless landings, folks need to practice engine loss on takeoff - that's an eye opener, as was discussed on the mailing list 8 - 9 months ago.
  9. Marc Zeitlin

    Kent's Long-EZ project

    And I clearly understood it as such :-). While I'm happy to get a "happy customer report", it wasn't necessary to defend me. I particularly liked the paraffin soaked wick - reminded me of the old Lucas electrical system in English sports cars - an elaborate system of tallow candles, was how they were described.
  10. Marc Zeitlin

    Kent's Long-EZ project

    I'm sorry - what? I missed that - too busy here eating caviar and grapes that the servants have peeled for me. We roast the servants after they've outlived their usefulness using benjamins as the fuel for the BBQ fire. The riches I've obtained from this business fund all the Boeing Business Jets that Burnside Aerospace leases. Back to playing in my pile of jewels...
  11. Marc Zeitlin

    Kent's Long-EZ project

    With fuel injection and balanced EGT's, the CHT stay relatively even at a much wider range of power settings.
  12. Marc Zeitlin

    Kent's Long-EZ project

    The dams are per COZY MKIV plans.
  13. Marc Zeitlin

    Cutting 7075-T6 Aluminum

    Try a tighter radius. You're bending it at a radius of 3 - 5 times the thickness - go to 1 - 2 t and it'll start to crack.
  14. Marc Zeitlin

    Sales I've seen

    You had a good Pre-Buy examination from a canard knowledgeable expert, of course, yes? And read up on all the wing attach fitting corrosion issues associated with multiple Varieze aircraft, and the implications thereof? And understand that VE's are (per RAF) limited to 2.5G positive and 1.5G negative loading? And have sat in and flown VE's to make sure that you fit and like them?
  15. Marc Zeitlin

    New Winglets and Rudders

    OK, so new the forum software doesn't easily allow for reasonable in-line reply formatting. Or if it does, it's not clear how to do it. Great. Onward. First, why do you think you have to build a whole new winglet? From the single pic from a weird angle that you posted, it looks like the damage is concentrated only at the tip. If this is correct, then this is a few hours of non-structural repair work, and some cosmetics. Second, my cousin's step-sister told me something once, but I didn't believe it. What makes someone think that the winglets are causing "too much" drag, and what does someone think would be better, and what would the ramifications of any proposed change be? Aerodynamically, and structurally? If you're not a structural or aerodynamic engineer, it's probably a bad idea to be changing aerodynamics or structures. There are many drag reduction modifications for VE's, LE's, COZY's and the like, and none of them involve changing the winglets. Blending, maybe. But not changing... Third, what makes you think that the winglet needs to be stiffer? What problem are you trying to solve? What failures have occurred due to lack of stiffness?
  16. Marc Zeitlin

    Kent's Long-EZ project

    quarts per hour? In which case you're WAY over the Lycoming specification of 2 quarts/hour that no one in their right mind would fly with if their engine was using that much oil, or hours per quart, in which case you're certainly on the high side of usage but not crazy high. Units matter... With an Ellison, you will be lucky if you can get all four cylinders to lean out the same amount before the engine gets rough - I never could, with mine, no matter what I tried. Hence the move to FI, and now all four cylinders lean very nicely - always white inside all four pipes, and I can get from 2750 RPM to 2400 RPM at altitude merely by pulling back the mixture. Anything in between is doable, and anything less than about 2650 RPM is LOP.
  17. Marc Zeitlin

    New Facebook Group for Cozy Mk IV Pilots & Builders

    Because two mailing lists, two web fora, and multiple generic facebook pages (which are horrible places to attempt to actually collect information) aren't enough?
  18. Marc Zeitlin

    Kent's Long-EZ project

    First, I am always impressed by Kent's willingness and ability to make stuff that most folks just purchase. Second, you might think that a CHT probe should last forever, but I've had two or three die on my over the course of 15 years. I have (for the past 10 years, anyway) used Dynon probes with my Dynon EMS. So for CHT probes, I HIGHLY recommend using bayonet mount probes (which the $38 Dynon probes are), since you can install and remove them with a quarter turn, and it's easy to adjust the compression of the spring to achieve good contact. Having worked on many engines that have the probes screwed into the head, it's a total PITA to install/remove them, whereas installing the bayonet mounts themselves only requires a long, large slotted screwdriver - the probes themselves install with fingers into the adapters. My $0.02.
  19. Marc Zeitlin

    Turbo Normalized

    So Dick Rutan had a turbo O-360 on his Berkut for a couple of years. It was a nightmare of trying to cram 43 lb. of sh*t in a 3 lb. bag, as well as having 36 lb. of heat from the turbo to dissipate in a 2 lb. heat dissipation bag. There just isn't enough space in an EZ cowl for the turbo, heat shields, and extra exhaust tubing (and still leave enough space to pour a pint of 100LL). He eventually removed the whole thing for an O-540, and is much happier with the performance and maintainability. If you're going to have water cooling and a radiator/water hoses, I cannot imagine (on an EZ - MAYBE on a COZY MKIV) where you'd stick a turbo and the associated extra hardware as well (intercooler?), with any access to anything. My $0.02.
  20. Marc Zeitlin

    Can she be salvaged?

    Maybe. Some hardware - axles, wheels, brakes, nose gear casting, firewall belcrank, rod-ends, etc. But it all depends on their state of corrosion and/or weather exposure. Might be worth something, might be a pile of crap.
  21. Marc Zeitlin

    Can she be salvaged?

    A beat up Varieze, with deteriorated fiberglass/epoxy both inside and out, and no records of the build or who the builder is/was. and 60% to go. No engine, no systems, unknown wing attach fitting status (look up Varieze Wing Attach Fitting issues). Anything can be done/repaired/fixed/completed. The question is how confident you would be in the result and whether it's worth the effort and cost. Since you don't know anything about these planes by your own admission, you are not out of your mind for considering it. If you DID know a lot about these planes, THEN I'd say you were out of your mind. Walk away from this disaster of a smoking hole and look for a Long-EZ or COZY project if you want to finish something someone else started, or just start a build from the start yourself if this is the type of plane for which you're looking. My $0.02.
  22. Marc Zeitlin

    More epoxy & glass questions?

    If you're going to build a LE or COZY, you should review the documentation for approved materials. There is a list of approved epoxies in the CP's and COZY newsletters. Proset 125 with 226/229 hardeners are approved epoxies. If you can get it for $90/gallon (including the necessary hardener), you should become a distributor. ACS sells resin gallons for $119 and hardener 1/3 gallons for $75 - $85. So a "kit" is about $200. I just bought 5 gallons of 125 from CST Sales for $104/gallon, and the 226 and 229 hardeners were $72 per 1/3 gallon. What's nice about the slow hardener (229) is that you get a nice long pot life with low viscosity for easy wet-out, and with even a low grade post cure get a reasonably high Tg and HDT. Even without a defined post-cure, the HDT is around 130F. IIRC, I used about 10 - 12 gallons of resin (not counting hardener) for my COZY MKIV, not counting West 105/205/205 for the micro finishing.
  23. Marc Zeitlin

    More epoxy & glass questions?

    So my first question when folks ask about different materials, etc. is "What problem are you trying to solve"? The airplane does not need to be stronger - no Long-EZ or COZY has ever had a structural failure in flight when built anywhere near the plans specifications. Unless you're going to use non "moldless construction" methodology - meaning building molds and using vacuum bagging type techniques, you're not going to substantially reduce the amount of epoxy in the build. You can't substantially reduce the thickness of most of the layups, because strength isn't necessarily the driving factor - damage tolerance on fuselage and wing skins is. So you're really not going to make them any lighter by changing cloth or epoxy - you could use lightweight engines, instruments and systems and save a lot more weight than you ever would with layup changes. Whether a fiberglass weave is measured in oz/sq-yd or in thickness is meaningless - you need a certain amount of glass to provide the stiffness/strength/puncture resistance required. Using Carbon in a contact (non-vacuum bagged) layup for structure is contraindicated, so unless you're going to bag everything, you should not use carbon (and it's way more expensive than glass, negating one of your goals). Kevlar is right out, as it has really crappy compression capabilities. There may be one or two places where a bit of Kevlar could be useful (under the nose puck for scraping resistance, for example), but nowhere else. So the short answer is really "no". Unless you're going to redesign the airplane to use different materials or build techniques (and it's been done - see the Berkut, which doesn't weigh any less and usually more than a Long-EZ) you're not going to be able to make the build time shorter, the airplane cheaper or stronger by changing materials. Feel free to argue the point - many have over the past 25 years - but none have shown one instance of any of their arguments holding water. These planes are what they are, and they're pretty well optimized from a design standpoint with respect to a balance of build time, cost and structural capabilities.
  24. Marc Zeitlin

    Aircraft Epoxy, Marine Epoxy what's the difference?

    Nothing, because there's no such thing as "Aircraft" epoxy or "Marine" epoxy. There are epoxies that designers have chosen based on their properties to ensure that the specifications of the device in question (aircraft or boat) will be met. If you use an epoxy that was not approved by the designer, then maybe those specifications won't be met, and you may either fall into the water or out of the sky. Since you're interested in LE's or COZY's, there is a clear list of approved epoxies that can/should be used, and you should pay attention to it, particularly to the fact that the best epoxy for the strakes/fuel tanks is the EZ10/87 due to its fuel resistance capabilities. There are reasons NOT to use particular epoxies as well - the West 105/205/206 are NOT approved due to the low pot life and high exotherm probability on structural (read thick) layups. In the grand scheme of things, the cost of the epoxy is a tiny percentage of the total cost of the aircraft - don't skimp here.
  25. Marc Zeitlin

    Red coloring after anodising 2024T3

    I hope that you are not anodizing any structural aluminum parts - only cosmetic ones...
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