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Justin

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Justin last won the day on June 9

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    Justin
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  1. Justin

    Smooth Operator

    I think you have not yet downloaded the Open EZ plans. You should do this, and read up on the scaling issues on a few of the drawings. Also go to this site and get the build manual:- http://www.aryjglantz.com/p/documents.html . Ary Glantz is one of the many heroes who have built the real thing from a lot of fairly uncoordinated data. I would not scale anything from bitmap files unless you have some kind of scaling marks. The Long EZ plans have these, and I still think this is a primitive way to go. Some proper dimensions cannot be beaten. At least, if you use the plans that you can download from the Open EZ project, you also have station positions, waterlines, and buttock lines with definite numbers. In my work/play with the Open EZ I have extended the nose. This is not because I think it looks nice. I thought the standard nose looked like it makes a downforce, and this is a bit absurd just ahead of a lifting canard. Someone else in the Long EZ forum posted a CFD pressure map that supports this hunch. I have played a little with the canopy geometry, and if I was building a real Open EZ I would use the UL390i engine. It has the same weight as the O-235, but for us in Europe, is more convenient to use than the old O-235, and with FADEC and fuel injection you can have a little more power, and unclutter the aircraft a little with no mixture or carb heat systems. Otherwise, I can't think how the basic Long EZ design could be improved. Anything else is a new aircraft. The EZ is a very clever, mouldless design. I am unlikely to build a real EZ. I am in my 60s and need a simple kit like a Sonex. However, I like playing with the EZ in CAD, and intend to make one or two for X-Plane.
  2. Justin

    Smooth Operator

    Oooer.... The side view you have there is the Berkut, not Long EZ. You cannot move the mainwheels rearward. It would load the nose gear too much, and you would need excessive speed on the take-off run to lift the nose. I think there isn't much of an issue with prop-ground clearance in the Long EZ. Perhaps this is why the engine axis is above the wing level. As far as I know it is not recommended to fly off grass. The wing height in the Berkut looks pretty similar to that in the Long EZ. I think the Berkut gear leg pintle is in the fuselage, so wing height has little influence. That Berkut picture raises a question. It looks like the engine axis is pitched upwards a tiny amount at the rear. Is that really the case?
  3. Justin

    Smooth Operator

    Canard Pusher Leaflet No.76 has an article on deep stall.
  4. Justin

    Some CAD renderings

    X-Plane has an add-on (included) called 'Plane Maker'. You can build flight models in there, but you need to be aware of its limitations. If you simulate your idea in X-Plane it will not accurately represent reality. X-Plane cannot simulate the effects of the heavily swept leading edges near the roots. It simulates only chordwise airflow. All kinds of vortices above highly swept leading edges will be created with high angles of attack, and you will risk loss of pitch stability. Kent points this out with his reference to the deep stall issue, on your thread. I think the Long EZ gets away with it because the canard is unswept, and the leading edge of the Eppler 1230 inboard wing strakes are fairly blunt, but some EZs have lost control. One of the CP Leaflets has an article on deep stall. I will find it later.
  5. Justin

    Some CAD renderings

    Thanks. Actually, I am not too bothered about renderings. I may model more for the Open EZ project, but the design data is a pretty dismal mess. I think people who have built EZs are heroes ! I am more likely to build a Sonex or Midget Mustang. Meanwhile, my EZ project may fly in X-Plane.
  6. The Rotax engine range is amazing, but in my view, the UL390 series makes the most sense if you want a modern (fuel injected with FADEC) engine with a bit more power. Some people have put O-320s in EZs. They are heavier than the O-235 , and I hear people need to add weight up front to maintain the CG position. The UL390 is about the same weight as the O-235, and has variants ranging from 140hp to 160hp. Its torque lies between that of the O-235 and the O-320. Of course, a new engine mount design is required for the UL Power engines.
  7. Justin

    Some CAD renderings

    Just a few more renderings. The nose is now only 6" longer than the standard one. I need to uprate the SSD in my computer, get back into X-Plane 11 and start on the flight model. I might do some more CAD modeling of the real structure and cockpit components, but is has low priority right now.
  8. Justin

    Some CAD renderings

    Hi Jeff, Go to the UL Power website, and on the 'manuals' page for each engine there are STP file downloads. The installation manuals are there too, and well worth reading. https://ulpower.com/en/engines/ul390/ul390i#downloads Justin
  9. Justin

    Some CAD renderings

    The engine mounts always need to be engineered for the job. It is likely that the torque reaction of the UL390i is similar to the O-235, because it revs slightly higher. Other higher torque engines are already used in EZs. You just design the mount for the job. In any case the Lycoming mounts are not used with UL engines. BTW, the UL390i is 140hp. The UL390iS makes 160hp. I think propeller design issues are more of a concern. These are things we can investigate in simulation.
  10. Justin

    Some CAD renderings

    Hello Kent, The UL390i is not bigger than an O-235, but is a little more powerful at 140hp. It is 4kg lighter, has a slightly smaller frontal area, and the starter ring is at the opposite end to the prop drive, so the engine cowl can fair better to a prop spinner. In my model the firewall is bog standard EZ, and I have now extended the upper engine blisters to make them fairer. I think this reduces the pinched in zone. I prefer not to affect the standard firewall. This might preserve a faster airflow over the cooling outlets (not modeled yet). I will model armpit intakes. I read about them in one of the CP leaflets. I prefer not to affect the standard firewall. The canopy is sleeker than the standard one. It has the same height and width at the canopy frame. It fairs to the standard firewall, and at the front I took some volume out with a more sloping profile. It does have a circular section at the pilot's head, and would be a little wider there then most, but not much. If I ever really build one I would mock up the cockpit first, to see if I would like it wider, but I used to enjoy the secure feeling of being strapped in tight fitting seats in my glider flying days. This is a 'paper plane' that will most likely only exist in the X-Plane simulator world. Cheers, Justin
  11. I think I will not build an EZ anytime soon, except for X-Plane. I will make a bog standard one first, just to benchmark it with known performance. Then I will make an adaption with the UL 390i engine and retractable main gear. Anyway, all these kind of projects start with CAD models.
  12. Justin

    Some CAD surfaces

    Hi Jon. Yeah. ´Makes good sense. CAD stuff can be presented as impressive even when it is complete rubbish. Crap in = Crap out. We see it too often in my day job. It is just good sense to be suspicious of it. With old, manually drawn projects, what CAD can do is fill in gaps, where the 'power of the pencil' gets away with ridiculous inaccuracy, or some error has been made, or there is simply missing data. I have to say that my view of RAF drawings is that they are pretty dismal, but good enough for skilled people to make perfectly good aircraft. The 3D models I received were treated with my normal suspicion, and failed. I am using data now from Open EZ, and I suspect there is little worth having the CD from TERF. I hope that provokes some informative responses that might change my view. One discrepancy I have found more recently is that the RAF drawing of the centre spar, when modelled in 3D, goes slightly through the internal wing core skins, as modelled from the Open EZ drawing scans. It is a small amount, but notable. The RAF drawing of the centre spar makes some approximations of the lofted wing skin inside surface. I know there was no CAD lofting when Long EZ was made, but you don't see so much error in Spitfire drawings from the 1930s. As far as I have explored the Canard Pusher newsletters now, there seems to be good laminate build data there, so laminate thicknesses can be determined. There are an awful lot of CP newsletters, and I have a lot more to learn from exploring them. Cheers, Justin
  13. Justin

    Some CAD surfaces

    Hi Jon, Thanks for your replies. Skills?.... I am an automotive designer with aerospace and defence industry experience. I have been using CAD since 1980. I am afraid I am impaired in some way.... I just cannot leave 3D geometric challenges alone, and end up in all sorts of projects. I also design boats, mainly sailing craft. There are about 100 boats afloat today that I have designed. The Spitfire work started in a purely geometric wing lofting challenge I fell into, but now I help a little on a restoration project over here, Well, I have latched on to Open EZ now. I am considering building a Sonex B. A long range touring aircraft could be quite a good thing for me. I like working with epoxy and glass, and an EZ is pretty unmatched when it comes to long range, speed and economy. I am an ex-glider pilot, and really like being in the front on any tandem seater, with very good fields of view. I will probably model an EZ in X-Plane 11, if I can find accurate airfoil performance curves. I did ask a question in an earlier post on this thread.... Is there really anything more on the TERF CD. than already published in Open EZ, and all the CP publications, pertinent to the EZ build? It is the only Rutan aircraft I will find time to play with, although the Q1 is quite fascinating. I will try attaching a high resolution rendering now.... Nope.. it didn't work. It was only a 3.3Mb PNG file. Cheers, Justin
  14. Justin

    Some CAD surfaces

    Hi Jon, Ary linked the very same page to me. Sheets A2, A7 and A10 are shown with scaling errors. It easy to cross check in CAD, because you overlay the drawings on the stations, waterplanes and but lines that are dimensioned by RAF. What is difficult to know is which axis on A2, A7 and A10 is incorrect, but the information in the linked page clarifies this. I am sure this is all Ary did his in Catia. I use Rhino for this kind of correction; sometimes even in Spitfire work I do.

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