jpolenek

It looks like it's on sale now. ($299.99) Joe Polenek

Ok. What is a good bandsaw size for this project? What is considered the minimum? Joe Polenek

Clarification: By "this tool", I mean a regular bandsaw, not the Jetsons version. Joe Polenek

On the topic of bandsaws... Besides the airfoil templates and jigs, what other parts of this project require this tool? I've already finished my templates quite easily without a bandsaw and I'm wondering if it's possible to get through the entire project without having to buy one. Joe Polenek

Has anybody else noticed that the Styrofoam that Aircraft Spruce sells for wing cores is NOT the same product as Dow STYROFOAM Buoyancy Billets? Buoyancy Billets have a smuch smaller cell size. Should I expect a different cutting speed for the same wire temperature? Joe Polenek

Airliners.net says its registration is LX-INT. Couldn't find any other info on it. Joe Polenek

Edge513;Thanks for your feedback and advice. (Nice sketch too!) Did you abandon the modification strictly because of the time it would add to the build, or did you run into some major roadblock(s) that could not be resolved? Who was to be the fabricator of the canopy? Did they foresee any issues in producing the shape you wanted? Joe Polenek

Does anybody know whose Cozy this is and how they made the canopy? Joe Polenek

In my last project, I mixed every batch for 5 minutes religiously. I'd consider 2 minutes a minimum. I also spend 80% of the time scraping the sides and bottom, because the centre gets mixed in the process anyway. Somebody on another forum once compared it to saving money. If you watch your pennies (scraping the sides/bottom), the dollars (mixing the centre) will take care of themselves. I also cut the end of the tongue depressor (stir stick) square, so it gets into the corner of the cup. Joe Polenek

Was the integrity of the failed metal tabs ever in question? Or is that just where the weakest point in that system happens to be. (Somehow, I always assumed that other parts of the plane would fail before one of it's primary safety components.) Joe Polenek

Based on accidents in which the seatbelts/harnesses were needed, do we know that the attach point retention is adequate? Have there been any cases that suggest that it is not? The shoulder brace that retains the harness attach points doesn't seem too beefy considering the function it might have to perform, especially on the Cozy where the shoulder brace has a wider span. (But I'm no expert on composites, and it still surprises me how much strength a seemingly small amount of this material can have.) Rich: Based on your experience, what is your opinion on the Cozy/Aerocanard configuration, and how it would perform if put to the test. Joe Polenek

Can somebody tell me how many of the $52 spherical bearings sold by Infinity Aerospace I'll need in total for my Cozy wings and canard? Are these easily adapted to the plans in lieu of the phenolic bearings? Joe

I have read A LOT of good things about Todd Silver's canopy work. Airplane Plastics has been an approved source for Cozy canopies so I assume they're good too. Can anybody comment on how Todd's Canopies and Airplane Plastics compare in terms of their capabilities, pricing, etc., especially for custom work? Joe Polenek

It won't burn up. Most hair dryers have an internal switch that shuts it off if it overheats. (Try it out by placing your hand over the intake.) Once it cools down, it will switch on again. The trick to keeping it from switching off is to keep the filter clear of dust, and to keep the air moving through it. This means that if air goes into the enclosure, it has to come out somewhere. An enclosure like this will probably have enough leakage to facilitate this air flow no matter how air-tight you try to make it. If you do make it really air tight, just poke some holes to let some air escape. One thing that will make it overheat is ducting the hot air from the enclosure back into the inlet of the hair dryer in an attempt to make it hotter. I tried this once on a small enclosure and it did shut itself off. However, with some experimenting, I balanced the amount of return air without triggering the shut-off, which maximized the enclosure temperature. As for timing, I left it running all night without any issues. Knife trimming is a bit of a pain since you would have to open up the enclosure to get at the edges and then re-seal it. I just let it all cure and trimmed with a Dremel tool later. If you do decide to go in and knife trim, plan to do it WAY earlier than you would with a room-temperature cure. The extra heat really accelerates things. Joe Polenek

Here are some photos of the enclosures I made to cure parts for my last project. They were made of polyethylene (vapour barrier or garbage bags) and duct tape, with hair dryers providing the heat. Very easy to set up. The small one was for a bulkhead, made of 2 garbage bags, and it used one hair dryer. The large one was for a fuselage side, made of 6 mil polyethylene, and it used 2 hair dryers. With the garage temperature well below 60 degrees fahrenheit, the temperature inside the enclosure was over 100F. Worked great! Joe Polenek

Coincidentally, the video clip you want to see just showed up on YouTube. Imagine that! Joe Polenek

It is in the video Building The Rutan Composites which is included with Cozy MK IV plans. (Doesn't look like Aircraft Spruce sells it on its own.) It's a great video, in which Burt Rutan and Mike Melvill demonstrate the basics of composite construction. It looks very dated, but that gives one an appreciation of how long these techniques have been in use. Joe Polenek

That's not a fair comparison, TMann. YOU do a 60+ hour chapter in 3 hours. :D Joe Polenek

Talk to someone who has built a plastic plane and they will give you just as many arguments in favour of glass & foam. (There's a reason Burt Rutan chose this method over 30 years ago and it continues to gain popularity.) Although I have not done any metal work to compare, I have done some glass/foam construction so far, and really anjoy working with the materials. Based on everything I've read, as long as you give it a UV protective coating, and paint it a light colour, there is no problem. I think that if hangaring these things was an absolute requirement and/or if they were known to deteriorate faster than all-metal planes, they wouldn't have become nearly as popular as they are. On the certified side, the number of plastic planes seems to be increasing all the time. Joe Polenek

It is a derivative of the Vespa, after all. Joe Polenek

OK. It's time to let the cat out of the bag. The attached photo shows what I'm going for. In addition to the canopy shape, the nose is also different, and the turtleback needs to be matched. (Disregard the air scoop on the bottom - it was just drawn in for looks.) This is why merely adjusting an existing canopy will not work. It is going to require a custom job. Free blowing could work for this, but it may further reduce the headroom. (Still need to work that out with a 3D CAD model.) I'm thinking that moulding the canopy would have the best chance of producing the exact shape that's needed, including widening the top for more headroom. This is just a concept until I can figure out if there are processes that will give me the canopy shape I need. If I can get that, the rest should be achievable. I'm giving myself 2 years to figure it all out and re-do the drawings accordingly, which is why I'm building the wings first. After I finish the wings, if I've determined that it can't be done, I'll have to bail out and revert back to the plans design. Joe Polenek

While intending to stick with the plans as much as possible, one modification that I do want to make is to re-shape the canopy for more side-to-side headroom. (Cozy MKIV). There are limitations to what shapes can be achieved by free-blowing, so drape moulding may be the way to go. (i.e. moulding the plastic directly over a male plug.) I tried to email Todd Silver of Todds Canopies numerous times but never got a reply. However, based on his website, drape moulding may not be one of his capabilities anyway. I called Airplane Plastics, the "approved" canopy supplier for Cozys. Jeff Rogers was extremely helpful and took his time to explain his processes. Unfortunately, he doesn't do drape moulding either. His way of getting custom shapes is to use the plug to build a 1/4" thick fiberglass female mould, build a steel frame around it, and vacuum-form the plastic into that. This process is somewhat more complex and is really intended for mass production, so it is cost prohibitive for a one-off for the average person. There must be a poor man's way of drape moulding a canopy and achieving decent optics if enough time and care is taken. I'd like to build the plug to the right shape and then either give it to a shop that will mould it for me (at a reasonable price), or use some home-made techniques to do it. Can somebody direct me to a resource for learning how to do this? - someone who has done this themselves with good results? - a mould shop that has this capability? - an EAA advisor who can point me in the right direction (I am a member.) - books, websites, etc. Joe Polenek

I ran across an article in Cozy Newsletter #83 entitled "Care of Glass Cloth" by fiberglass expert Gary Hunter. The age of the fiberglass doesn't seem to matter. If the glass has gotten wet then it's no good because the adhesion-promoting "sizing" (a water soluble coating) has likely washed away. High humidity is not a problem as long as it hasn't caused mildew. If in doubt, test a piece and if the epoxy wets out properly, the glass is OK to use. Joe Polenek

... price, availability, whose economy you're supporting when you buy it, ... Joe Polenek

Given that we always use epoxy to reinforce something (mostly glass and sometimes fillers), the "superiority" of MGS on it's own is academic. It seems that the quality of the lay-up (correct epoxy content, fiber orientation & straightness) has a far bigger effect on the strength of the lay-up than which of these epoxies is used. Joe Polenek