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Jon Matcho

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Everything posted by Jon Matcho

  1. *** IMPORTANT *** Inaccurate reference measurements have been identified in the Open-EZ Revision #5 Templates that can result in improper airfoils. In 3 of the 14 templates the X and/or Y reference dimensions are off by exactly 1 inch. This was a result of human error (mine) where I used the 1" mark on the tape measure as "zero" (for accuracy), but forgot to subtract 1" at the far distance. Specifically, the following is the status of the Revision 5 templates: A1: 23" x 16.5" is good A2: 23" x 17" should have been written 23" x 16", building to incorrect dimensions will result in: The GU canard core templates will be ~1/4" less thick than they should be. The instrument panel bulkhead will be ~1/4" short (relative to the waterline). Printing and not scaling to match the measurements would have been better in this case (assuming a ~1/8" typical "first try" inaccuracy of most large format printers). A3: 23" x 17" is good A4: 23" x 17" is good A5: 23" x 16" is good A6: 22" x 17" is good A7: 23.5" x 18.125" should have been written 22.5" x 17.125", building to incorrect dimensions will result in: Just a bigger reference drawing, since the aspect ratio is preserved 1:1. Printing and not scaling to match the measurements would have been better in this case (assuming a ~1/8" typical "first try" inaccuracy of most large format printers). Ary Glantz has an excellent write-up on his blog site how he discovered this issue and corrected it (although Ary's workaround is unnecessary if you just use the corrected measurements indicated in red here). A8: 23" x 17" is good A9: 23" x 16" is good A10: 17" x 22" should have been written 17" x 21", building to incorrect dimensions will result in: A longer main wing chord and overall skewed hotwire templates at butt-line 55 and 23. A11: 23" x 17" is good A12: 23" x 17" is good A13: 23" x 16.5" is good A14: 23" x 17" is good The now-corrected dimensions above are entirely accurate and verified. If you print templates, adjusting scale as necessary, using these corrected dimensions you will have perfect templates. If your reference checks are off at all, it means your prints are off; NOT the marks themselves. What to do if you've already built something Most of the templates are accurate, and there's no cause for alarm in those areas. However... Canard (the 'GU' canard) If you have already built your canard with the A2 templates you must destroy your canard and either find plans for the Roncz canard or wait for the next Open-EZ update. If you've gotten this far you should know you would prefer the Roncz canard versus the GU canard anyway (and hopefully never built the canard). Main Wing If you have already built your main wing with the A10 templates you may have seen butt-joint surfaces off ~1/8" along a straight-edge. This can be addressed as part of the standard wing glassing, filling, smoothing, and finishing operations. Regardless, I would wait for the updated Open-EZ templates to compare against before you consider flying. Your responsibility as a distributor of 'Open-EZ Rev 5' template files The Revision 5 templates have not been available from the Canard Zone since January 26, 2010, but several web sites and other sources have since made these templates available (even before then). If you manage one of these web sites or have downloaded the template files and shared with others, it is your responsibility to notify everyone who has or will have downloaded the template files of this information. If you know of one of these web sites or download locations please pass along and share a link to this post. Next Steps Plans and efforts are already underway for an update to the Open-EZ templates, with a much improved technique for ensuring accurate analog AND digital template versions. Understand that simply because someone may have templates or drawings that are "in CAD" does not necessarily make them more accurate than something hand-drawn on paper. The concern is twofold: 1) what source was used to serve as the CAD reference (was the source accurate?), and 2) how exactly were the templates (dimensions) translated from analog to digital? In the case of the Open-EZ templates, several original plans were utilized (at least 4 different complete original sets) to determine and set accurate reference dimensions and marks. The Open-EZ templates are precise to <1/64" relative to the templates that were inspected. Please be careful. If in doubt, stop and get help, and by all means feel free to share your situation here. Sincerely, Jon This post has been promoted to an article
  2. Jon Matcho


    Frank, did you manage to make contact? For those following along, here's Aeromatic's website: http://www.aeromatic.com
  3. Jon Matcho

    Engine Selection

    Ha -- that was good for a morning laugh! Thanks for sharing Chris!
  4. Jon Matcho

    Canards made AOPA Live news

    The Rough River fly-in made the news on AOPA Live this week.
  5. Jon Matcho

    Canopy Trim

    I'll definitely be making a trip to the automotive store! Corners without the tape kinking up are the key.
  6. Jon Matcho

    Canopy Trim

    I took a closer look at your pictures. Your inside shot is a touch blurry so that might be hiding some of what you're talking about, which I think is exactly what I am dealing with right now (see the pictures). I built-up a "tape dam" using several layers of painter's tape. The micro build-up is quite thick, and my plan now is to remove the thick "tape dam" and replace with just 1 layer of painters tape. I am going to put down a final treatment of micro (just for edge aesthetics), wait until the micro gels up a touch so it's not running, then pull the tape so I have a clean line. I'll put another layer of tape down after that, just for protecting the plexiglass so I can complete final sanding and whatnot.
  7. Jon Matcho

    Canopy Trim

    You might be right! Diatomaceous earth, which is tiny broken-up bits of fossilized diatoms, is used as an organic gardening material to prevent bugs. I also just learned that it’s used as a stabilizer for dynamite. So there you have it, our planes are “Organic” AND “dyn-o-mite”!
  8. Jon Matcho

    Canopy Trim

    That was my first reaction as well. I am now hesitant to show the quality of the joint I have come up with for the Glassair III door/window repair I've just done. Back to the shop... Andrew, consider that good and get some protective covering back on that canopy! Seriously, at most you could put some thin painter's tape on the window for a straight edge, then put on some West until it gels up, then pull the tape and let it cure.
  9. Jon Matcho

    West 105 is really easy to sand

    I was working on sand-and-fill using the West 205 105 epoxy system, which is just a mix of micro-balloons ("micro") and epoxy. I can now confirm these statements: Sanding after the MGS epoxy system cures is like sanding a rock. Sanding after the West system cured is much easier. I still don't like finish-sanding.
  10. Jon Matcho

    West 105 is really easy to sand

    Another thing to keep in mind is that if you start sanding too early when the epoxy is in the "bubble gum" stage. This will end up making a mess of your sandpaper and you won't get much done. I just found this out after sanding on West's extra slow hardener (209) from a session last night (~9 hours ago -- my shop is getting cool these days so that didn't help). I haven't had much of a problem when sanding after fully cured, but then again it's never fun sanding drips away. In general I have been happy with the sandability of West 105 with glass micro-balloons. Otherwise this foray into finish-sanding could have been thoroughly discouraging.
  11. Terry Schubert, the editor of the Central States Association Newsletter and host of the Rough River Fly-in, has asked me to share this here with everyone:
  12. That was a fast and low trip, actually from SMQ (Bedminster, NJ) a short ride from my house. This past weekend I saw a canard go overhead but when I ran in to check Flightaware I could not find it. I love hearing that unique sound and getting confirmation when I see it above. The Piaggio Avanti 180 makes a similar sound and is just as beautiful.
  13. When running a weekend errand a while ago, I decided to take a quick detour to visit the local airport. I don't know anyone at this airport beyond a flight instructor, but it's always nice to sit for a while and watch airplanes. On my way out I passed a lone hangar that I'd never seen open before. Out of the corner of my eye I thought I recognized the telltale signs of the back-end of a canard aircraft (two vertical stabilizers, pusher prop in the back, etc.) I circled back and sure enough it was a canard, but this canard was different. It had two engines in the back! Feeling like a local airport bum, I got out of my car and introduced myself to the gentleman working on the aircraft. It turns out that it's one of the first -- if not the first -- customer-built and flying Velocity V-Twin. We talked canards for a while, I found out he was a local mayor, and then I had to leave him to it before I wore out my welcome. It's amazing to me that this plan is (a) on this airport that I thought was a bit too short for canards, and (b) just 6 minutes from my house!
  14. Jon Matcho

    West 105 is really easy to sand

    I feel like I have a chance at dealing with the Finishing process when I get to it (which I've been told is 33% of the entire build). West is your friend and there are a lot of good guides out there, such as this one:
  15. Jon Matcho

    West 105 is really easy to sand

    I'm actually using West 105 Resin with the 209 Extra Slow hardener. The properties for 209 are slightly lower than the 205 Fast hardener, but the window before cure is MUCH longer. I like going to bed sometimes. ? Ah, I just learned about the line of West Filler products. Cool, I'll have to get some and try them out! Thanks for the tips -- my next question coming in here today was going to be about when/how to transition from epoxy/filler to primer.
  16. Jon Matcho

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

    I'll go out on a limb and say that Keith and I both meant "just follow the plans." Where else would one "follow the layup schedule"? My point is not "exactly incorrect" and is not even "just" incorrect. If anyone were to follow the plans exactly ("follow the layup schedule") their planes would build and fly as intended by the designers. In the Cozy IV plans (not sure why we're discussing the Cozy in the Open-EZ topic, but OK) Section 14 Step 6 states (bolding and underlining is mine): Some deviation from theoretical is acceptable, if due to the tape being thinner or thicker than .025 after removing cross threads. It is acceptable to use one or two layers more, or one or two layers less, to fill up the trough. For the Long-EZ Section 14 Step 7 is also clear on how to do this: Measure the depth of the spar -- if the layup is over-size, sand (maximum of .04) to size. I have not checked the Canard Pushers, but in either case following the plans and incorporating all changes (Canard Pusher newsletters, or Cozy newsletters if we're talking about an Open-EZ 4!) will produce a good result. Perhaps there are developments in the Cozy community post-Nat Puffer, and I would certainly research these tips and recommendations (notably from Marc -- the human center of the Cozy universe -- and several others such as @Kent Ashton). I suspect Cameron does not have Long-EZ drawings so a methodology to link the Long-EZ plans in the plans-only TERF CD to the Open-EZ drawings (same measurements as Long-EZ drawings) is flawed from the onset. My point is that the same confusion would have been produced in 1984 by doing the same thing with Long-EZ Plans and Long-EZ drawings. Presently there are no Open-EZ plans per se; one needs to use Long-EZ plans. Cameron, how specifically did you get your Open-EZ measurements? If you are interpolating top/bottom trough sizes from the Open-EZ drawings, please do the same with actual Long-EZ drawings and I assure you that you will end up at the same place.
  17. Jon Matcho

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

    Seriously, where are we at with this? Are we good, or am I still confused?
  18. Jon Matcho

    Re-do... part 2

    I do believe you missed the side you wanted captured on that PDF -- it's blank.
  19. Jon Matcho

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

    Still putting the Cozy aside, no. ?
  20. Jon Matcho

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

    Ah, I think I see the issue: comparing drawings to a layup schedule was never meant to be. ? In other words, and still putting the Cozy aside, given (a) and (b) below, the conclusion is true: a) The layup schedule and tape thickness noted in the Long-EZ plans on the TERF CD matches the printed Long-EZ plans last published by the Rutan Aircraft Factory. b) The Open-EZ drawings Rev. 5 matches the printed drawings last published by the Rutan Aircraft Factory. Conclusion: You could compare your #1 and #2 using the original Rutan Aircraft Factory counterparts and produce your same results. Now what?
  21. Jon Matcho

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

    I suspect the source of your data is off (as Keith also suggests with scaling issues on your drawings). Putting the Cozy drawings aside for now, I assume you must be comparing the following: Long-EZ drawings that you have acquired from somewhere. Open-EZ drawings that you have carefully printed and measured, or measured on the computer using a digital tool. As Keith points out it's most important to follow the layup schedule, but I am still concerned over the above and the source of your data. Please share more about how you came to #1 and #2 above. Are the Long-EZ drawings copies you received from somewhere? I know I once received drawings from someone in Australia and ended up throwing them out suspecting they were copies of copies. The Open-EZ drawings were taken from actual Long-EZ drawings and verified against other actual Long-EZ drawings, so I trust what's in the Open-EZ drawings but can't verify what you may be comparing to. At the end of the day the Long-EZ and Open-EZ drawings should have identical measurements.
  22. Jon Matcho

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

    The Open-EZ does not introduce any new design changes. The Open-EZ specifications are meant to be identical to those of the Long-EZ. The TERF CD contains the Long-EZ plans, which require all applicable Canard Pusher updates to be accurate. Are comparing the TERF CD's Long-EZ plans with something else you have on hand?
  23. I know the feeling -- opened an old box and found some more epoxy this past weekend! How's the weather holding up? Are you managing in your heat tent?
  24. Jon Matcho

    Kent's Long-EZ project

    That's great -- I think I will copy that design! Coremat as a core material reminded me of the Mini-IMP and Molt Taylor's TPG (Taylor Paper-glass) which follows the same principle. This is basically creating box structures; something we do all the time with foam, but in just a smaller scale here. You could even use balsa wood for this application. I missed the memo on "PVC wiring". What exactly is it and what's wrong with it?
  25. The NTSB had a press conference on it. Apparently a wing departed the aircraft. http://www.covingtonleader.com/news/police_fire/ntsb-pilot-crashed-after-wing-separated-from-jet-eze/article_5c57009a-afc2-11e8-a5db-0f8e921ec5cc.html I spoke w/Lance last year about his passion for jet-powered canards. He was quite the character and I could barely keep up with him even over the phone. He will surely be missed. RIP Lance.