Jump to content

Marc Zeitlin

Verified Members
  • Content Count

    1,070
  • Joined

  • Last visited

  • Days Won

    19

Marc Zeitlin last won the day on November 9

Marc Zeitlin had the most liked content!

Community Reputation

43 Excellent

2 Followers

About Marc Zeitlin

  • Rank
    Flying Cozy MKIV N83MZ
  • Birthday 08/06/1957

Personal Information

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

Flying Information

  • Flying Status
    Flying - 15200 hrs.
  • Registration Number
    N83MZ
  • Airport Base
    KTSP

Project/Build Information

  • Plane
    Cozy Mark IV
  • Plane (Other/Details)
    COZY MKIV
  • Plans 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/

Recent Profile Visitors

781 profile views
  1. That's AN-8 Aeroquip 466 (or the equivalent) hose with integral silicone firesleeve.
  2. What "tubing" are you talking about? The hoses from the oil cooler? The aileron pushrods? I don't know to what you're referring.
  3. Not just the pull of the springs, but warping of the glass. I fixed mine when it warped by cutting slices in the top surface glass, supporting the left and right edges and weighting the middle so that the LB would take a slight curve - higher at the sides. Then I glassed 2 BID over the slices to lock in the shape. That was about 9 years ago, I think, and it's kept shape perfectly since - when it's pulled up, the sides hit about 1/8" early and then the center pulls up, keeping the whole thing flat.
  4. Hah. Here's what I have - no imagination necessary. 99% uncovered when open, 90% sealed when closed. I rarely use it, since I don't live in a cold place. But since it exhausts down below the strake, I do get a pitch trim change when I shut off the airflow to the cooler. THAT was strange.
  5. Desser Monster 10-ply retreads. 350 - 375 landings on a COZY MKIV.
  6. 10 - 15 lb. max. If the empty weight of a Long-EZ is 1100 lb., it's a single seater, and replacing the panel isn't fixing that.
  7. Now we're getting somewhere. At almost the aft CG limit of 103", somewhat under design MGW and an IAS substantially higher than the design cruise speed of the airplane (remember, the Long-EZ was designed for an O-235 engine of 115 HP, so has a design cruise speed in the 120 - 125 KIAS range (call it 140 mph IAS), it's not at all surprising that the elevator would be reflexed up a bit. That's 50 mph over the design IAS, give or take - the elevator trim position will need to be higher than trail. There are O-540 powered Long-EZ's and Berkuts that will run out of up elevator at max power, and will still be climbing even with the elevator deflected full TE up (at well over 200 KIAS).
  8. In order to answer this question in a useful manner, you have to discuss GW, CG location, which airfoil (GU or Roncz) and IAS. Without that, any comment will be meaningless.
  9. I'm obviously partial to canards, and besides being cheaper to build than an RV-10, they're a lot cheaper to operation. But in any case, 380 - 390 is NOT pushing the max front seat weight limit, because there IS no front seat weight limit (ignore the 400 lb. limit Nat stated - it's not based on anything other than him accidentally taking off once with two people in the front seat without taking his ballast out and scaring himself on the takeoff roll). What there _IS_ is a forward CG limit. With 390 lb. in the front seat (call it 400 lb, as you'll probably both be clothed and have other crap with you) in MY plane you'd be at about a CG of 97.8 at landing - about 0.3" aft of the fwd CG limit. If most of your flying would be with 2 folks and 400 lb. in the front, I'd recommend NOT shortening the canard, but leaving the 3" on each side, and moving your CG range forward by 1" - 1.5". With a 200 lb. pilot (again, in MY plane) you'd then need about 40 lb. of ballast in the nose when flying solo to keep the CG forward of the NEW limit of 101", rather than the current limit of 102". The biggest issue will be whether you will fit, side to side. And this can only be answered by finding one and sitting in it.
  10. Uggghhh. Variezes and LE's are very susceptible to main gear mounting issues. Who did your pre-buy? Did they jack the plane off the ground (both wheels at the same time) and check for play in the gear? If there's known noise when the gear is used... If the previous owner KNEW that they had extensive play in the landing gear and misled you about the severity of the problem (and your pre-buy expert didn't catch it), then you've been taken for a ride. Normal and stop when "everything gets broken in"???? You need to: ground the plane Jack BOTH mains off the ground at the same time Grab one main wheel and push forward and backward fairly hard, looking for how much motion you can get at the axle (you'll need VERY stiff/strong sawhorses so that the plane won't move - JUST the gear) Note how much the wheel can move forward and aft from the neutral position As you push forward and aft, watch the landing gear strut where it enters the fuselage side - there should be almost zero motion there. Anything more than 1/16" - 1/8" is a problem - anything more than 1/8" requires immediate repair Do this for the other side as well Get a second person to watch inside the hellhole (if you have a hellhole cover underneath, they can watch through there - if not, they can watch through the rear seatback) - they may need a flashlight and a large inspection mirror to see what's going on. They are looking for relative motion of the gear attach tabs to the aluminum brackets, or of the brackets to the fuselage side, or some other relative motion Once you know where the relative motion is, a fix can be planned I've repaired numerous planes that have had issues with bracket attachment, broken LG tab bushings, wallowed out bracket holes, etc. It's a big job to fix, but it HAS to be fixed. The last thing you need is for your gear to collapse and ruin the prop and engine, not to mention the airframe repairs. Given your pictures, I think you've got a serious gear failure on your hands, but only an in-person examination can say for sure. I will be traveling from Atlanta to Tucumcari on 8/29 - I might be able to arrange a stop in Wichita for an hour or two to take a look if you have jacks to get both of the gear off the ground at the same time. You can contact me directly at my email if you're interested in trying to arrange this.
  11. No two Berkuts kits were identical, and the plans were incomplete, and may or may not have matched the parts you may or may not have been given. Plus you had to generate your own POH. So, yeah. Other than that, no QC issues. You might want to check with James Redmon about the level of QC. Dave Ronnenberg is a GREAT fabricator, and builds great airplanes. But, the above...
  12. There are a number of folks starting down the path of different types and sizes of canard composite kit aircraft. I don't hold my breath that any will be successful from a business standpoint (and one will certainly not be from a technical standpoint), but I wish most of them luck and hope I'm wrong. With respect to your reason for wanting canards to continue - I love my COZY MKIV, and wouldn't trade it for any other aircraft out there (except maybe a Pilatus PC-12, if someone else paid for the fuel and maintenance), but while in theory they're safer due to the stall/spin resistance, a study of the accident rate of canards vs. conventional planes over the 45 odd years that they've been in existence does not show any advantage in either fatal or non-fatal accident rates. There are other airplanes with similar performance and range as well.
  13. So contrary to a previous comment, the Berkut was stretched (from the LE dimensions) 12" between the wing and canard, with 6" being aft of the rear seat to give room for the retracts, and 6" forward of the rear seat to give more leg room in the back. This substantially changed some of the aerodynamics with respect to CG range for the aircraft, which has NEVER been properly characterized regarding the neutral axis and stability or with respect to deep stall susceptibility. Stretching the aircraft turns it into a new airplane and requires more skills than "that looks about right". Is it possible? Sure. Would I recommend it? Nope. The E-Racer kept the canard/wing relationship - there was no stretch. It moved the front seats aft, so that a 2nd person in the front seats wouldn't change the CG enough to require changing ballast. The aerodynamics were not changed (other than the wider fuselage). The short answer is no, because the weight of the fiber in one of these planes is a relatively small percentage of the total weight of the aircraft. The cost of materials, vacuum bagging, etc. is not worth it for the theoretical weight savings. I won't even get into the issues around needing to use molds if you're using carbon. There are a lot of longer answers as to why this is contraindicated in the archives here and in the COZY list as well as the canard-aviators mailing list.
  14. People are funny. That plane MIGHT go for $25K, since it's got a relatively newer panel and a nice paint job. I'd be worried about the absurd nose and extra strakes from a stability standpoint, and the MGL equipment that almost makes a good engine monitor, with the other steam gages in the panel. Holes in the panel, no labels for switches, CB's, manual nose gear, no landing gear strut fairings, but sure - WTF - ask $50K. Be amazed when you get no offers...
  15. I vaguely recall you pointing that out to me before. And which I have tried here. Eh. Closer to 10 - 15 seconds, by the time you're done with it, but yeah - it works, and I'll try to remember for next time... Thanks.

The Canard Zone

×
×
  • Create New...

Important Information