brainfart

Oh, you already mentioned that as your second option. It might be more time consuming, but the result should be much nicer, too, since you can take it out and work on it without endangering the canopy. http://www.sikaindustry.com/ind/ipd-marine/ipd-ma-products.htm

Sikaflex offers such products with different colours. It doesn't need to be black, I've seen, transparent, white and grey and many more. Give them a call or send an email and see what they recommend. These polyurethane glues and sealants are widely used in construction, car manufacture, transportation, marine etc. One of the advantages is the flexibility. The best glue line isn't necessarily rock hard (like epoxy glues), it's sometimes better to have a somewhat flexible glue because it will take up mechanical stresses better and allow some deformation. I wouldn't call these glues/sealants inferior way to do the canopy bonding at all, whole cars are glued together using them. Regarding the internal canopy structure, I wouldn't lay up wet glass on the Sikaflex unless they specifically tell you to do so. I'd rather build the structure using the canopy as a mold, then take it out and glue it back in using the Sikaflex. Can't hurt to do some experiments and learn more about the canopy to epoxy bond strenght before using it on the actual plane.

> What would be the best fire retardants to use, that will not kill the > pilot/passengers in the process? Does not generate poisonous gases, does not > in normal use compromise the structural strength and does not add excess weight. Simple answer: Does not exist. Maybe change the thread title to self extinguishing resins?

The number of errors in that paragraph alone is enormous. Astatine... yeah totally dude! And organic bromides are oxidisers?!? BTW, halon is just another brominated gaseous alkane... and that means it will disappear quickly, in less than a second under the conditions found in an average airplane. > There's a lot of information about "non-brominated" resins which should give us a clue not to use it. Sure, I was merely giving an example from my supplier, trying to point out that self extinguishing resins exist. If you find other resins which fulfill the requirements, use them. Other flame retardants are known and in use. Add a bunch of hydrated alumina to the resin, or throw in some red phosphorous (yes, contrary to common sense that stuff ist is a flame retardant too). I don't think that brominated resins are a big problem here when they are used in the engine compartment. Poisonous gasses aren't an issue as long as the fire is behind the firewall and everything is airtight, or you can somehow let air into the cockpit.

> One thing that I wonder about is whether a brominated resin would still meet strength requirements, I don't know if they are inherently weaker, except that they have a higher specific gravity due to the heavy bromine and the inorganic additives they contain, which would affect some of the numbers [strength/mass]. They also have a higher viscosity which might lead to a greater resin content in the laminate. None of these are serious problems, just wanted to point out the little I know. In mass transportation only flame retardant plastics are used for the interiors for safety reasons.

FAR 25.853 requirements (burn tests, smoke density) briefly explained: http://www.kydex.com/briefs/131.pdf

Ever considered using self-extinguishing epoxy in that area? I know of several suppliers which sell brominated laminating resins to the general public. They aren't prohibitively expensive either. Such resins are being used extensively in commercial airliners and trains. Might be worth using around the firewall. Quote: "Low-viscosity, modified, bromine-containing epoxy resin, ideal for manufacturing self-extinguishing fibre composite components exhibiting good mechanical properties. The burning behaviour of these components complies with the requirements und FAR 25.853, even for small wall thicknesses below 1mm." Current prices: 2.5kg resin €36 + VAT 5.0kg resin €69 + VAT 10kg resin €115 + VAT

I'm tempted to say that this glass is all way too heavy. E.g. 1250g/m2 is approximately (1250/30)*0.8 = 33 ounces/square yard. Even the biaxial cloth (which could be considered two uni layers stitched together) is much heavier than the recommended glass, apart from likely differences in weave, filament diameter and surface treatment/sizing.

I've worked with basalt fiber, the looks are not so great but it's quite a bit stronger than glass and only about 15% heavier. It's widely available here in Europe and pretty cheap, too. http://www.basfiber.com/ Visible Kevlar is actually not a good idea, it degrades seriously in sunlight! If you place a piece of plain kevlar in the sun you can see it darkens in only a few hours. Loss of strenght is considerable.

Yup, airlines use them and I've also seen them in buses. Usually made from plastic though.

Traceroute will show you where the bottleneck/congestion is. You can also try pathping.

> So... isn't there a problem because the rest is fiberglass? I don't think so. The problem is usually not the little change in size directly caused by the expanding or contracting material, these changes are pretty small and the tolerances big enough. We are talking about fractions of a millimeter here. The problem is when you have laminates made from different components which cause a bi-metallic strip like bending of the laminate, this can cause pretty big distortions. Imagine for example a sandwich with carbon fiber on one side, then some foam or honeycomb and glass on the other side. It might be perfectly flat at a certain temperature, but when you heat it up or cool it down it will bend considerably, especially if the part is large. If both sides are made from the same material or material combination and have the same number of plies it will remain flat. Sorry, since English is obviously not my native language this is a bit hard to explain, I hope it made sense.

Carbon fiber has a weird property: it will not expand when it heats up. Actually its expansion coefficient is not quite zero, it's even slightly negative, so it will contract slightly when the temperature rises. But for all practical purposes you can consider the coefficient of expansion to be zero.

I might be totally wrong here, but if you want more stiffness, why not carbon fiber?

Sorry, off-topic, but since Hans might like it, too: http://www.spang-air.de/Marville_Feb_08_-_2.jpg 3cyl. VW TDI diesel engine. This engine, when used in the VW Lupo, resulted in the world's first car in series production consuming as little as 3 litres of fuel per 100 kilometres (78 miles per US gallon) back in 1998. Now it's flying.

BMW engine. Just mentioning it since you might not have heard of it yet. http://www.spang-air.de/willkommen/BMW_Engine/bmw_engine.html (in English) about 100hp (with motorcycle exhaust muffler), runs on regular auto fuel, 3gal/hr@75%, widely available... Just saying.

> If you are going to post cure, It kind of bothers me that people are obviously using epoxies like the L28X range without post curing. L285 with hardener 285 will only develop its great mechanical properties and high Tg when post-cured, and H286 and H287 definitely need heating when making parts in moulds for demoulding because they end up very brittle without it. Actually every epoxy with a higher Tg than West system should be post cured, they all benefit from heat treatment.

Ideally you post-cure the parts still in the mould (when working with moulds), by slowly raising the temperature and keeping it there for a few hours. If you don't have a big enough temperature controlled curing chamber, you can build a tent out of plastic, place the parts in a big cardboard box, surround it with styrofoam, or build a box out of sheetrock or similar material and put a heater or a bunch of light bulbs inside. Most homebuilders don't seem to bother though, which I find kind of weird. Then again building a plane takes years, and by that time the epoxies will have cured to a sufficient degree and the sun will take care of the rest.

Is it even possible to open the canopy in flight? There are a couple of videos on the internet showing some testing done with a glider cockpit attached to a car, and the "pilots" tried to open the canopy at different speeds. It was nearly impossible at most speeds to open that thing. And even when they got it opened, getting out of the plane was another difficult task, it mostly didn't work. And these cockpits are more open and easier to get out of than the average EZ... Has anyone ever bailed out of a flying canard, successfully or not?

The attachment isn't working for me. Anyone else have the same problem?

The MGS285 prices you all have to pay seem ridiculous. The stuff is roughly the same price as West System in Germany, maybe a little more expensive. The other MGS resins are even cheaper than WS. Ok, one reason is the current Euro to American peso exchange rate, but the hazardous shipping charges and all that add to the price, too. To make y'all a little more envious, epoxies including L285 are being shipped without any hazardous material surcharges here, are widely available from several suppliers, and it usually takes about 2-4 days for your order to arrive at your doorstep. Maybe we should set up some illicit L285 smuggling ring? Anyone interested? Good news regarding the Interglas/Hexcel interchangeability, raiki. The weight per area seem slightly different though, any comment on that?

Glue the foam with a slurry of epoxy and microballoons or something similar, but don't get any of it on the foam where the cut will be made. The adhesive should hold the foam together but shouldn't interfere with you hotwiring it. Once you are finished with shaping and sanding the foam you can carefully inject epoxy into the joint if necessary and apply micro to the outside.

Might be off-topic, but since you mentioned uspto.gov: You can search US and international patents and download and print them in pdf format for free at the European Patent Office: http://ep.espacenet.com/

> I have a 912 in my Kitfox and have considered swapping it for a 0-200. > Roatx parts are just rediculously expensive. When Lycoming parts look cheap > something is wrong. Apples and oranges. What's true for your corner of the world isn't necessarily true for him.

http://www.canardzone.com/forum/showthread.php?t=142 http://www.canardzone.com/forum/attachment.php?attachmentid=17&d=1039368913 (This is weird, I cannot edit my own posts?)