Hey Guys I have been successfully operating a fibreglass spring on my Catalina. It saved me more than 2 Lbs of weight compared to the double steel setup and it does not sag as much/a bit stiffer which prevents my rudder to be hit (remember the Catalina is extremely tail heavy compared to the other Avids ....static, wings unfolded I have about 110Lbs weight but when I fold the wings the weight goes up to about 220Lbs!!!) I was going to make a spring but did not have the equipment to prevent air bubbles between the layup ( oven and bagging technique). I found the easy way to by a 84-96 Chevrolet corvette rear fibreglass rear mono leaf spring. like this one on ebay https://www.ebay.com/itm/Corvette-rear-fiberglass-leaf-spring-84-85-86-87-88-89-90-91-92-93-94-95-96-NYU/372502247525?hash=item56badd3865:g:OcgAAOSw8PJb7Jlq:rk:8:pf:0 With it I cut 4 different length to make the perfect one having good strength, rigidity and rebound. I tested mine to over 2000Lbs no problem See the picture of my tail assy below. Last picture is the before..
I would guess that plexiglass is easier to mold then lexan. I think perhaps the idea of the window being bigger then the door and going back 5 or 6" has some merit. That would in effect widen out the fuselage where your arm would go without changing tubing or fabric. You might gain an inch or so on each side. Let the door get a rack in it to fit the window so it protrudes out on the bottom somewhat perhaps?? JImChuk
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I used two tubes across the door on my challenger and used two pieces of lexan. Makes changing door glass easier and cheaper when you can do half of it when it gets scratched, and it will eventually. It also makes it easier to fit the compound curve of the bowed out door with two pieces. A little care matching them up and the crack between them is very small. Or use a strip of rubber edging between the two.
With the fiberglass spring, I think I got a couple of dry spots between the layers of fiberglass and that's where the crack started. I never got around to building another, but I'm sure it could be done. A friend of mine has been building a Murph Rebel, and he got a fiberglass tailspring from Murphy with the kit. I used to have a main landing gear on my Himax that was all fiberglass. Built by a guy out in Pennsilvania. He has an interesting website describing how he built fiberglass parts. Look at the fourth bullet point up from the bottom. Also he has a lot of other good info, including how to run a 2 stroke engine without cooking it. JImChuk www.curedcomposites.com/
I've been thinking about something like this for my -1 (should i call it silver fox?). I guess you'll show your progress as you go but how are you going to form the lexan? a few of my ideas have been 1: build a frame to clamp the lexan in and put it over a heat box until it sagged to where i wanted it and use a frame just like you're doing with the middle tube bowed out. 2. same as above but make the bubble oversize so the aft end of the door touches the fuselage 5 or 6"s aft of the opening. Might look a little goofy and haven't thought about how I'd build a frame for it yet.
ak, they say it is 8000 watts, which is 27,000 btus, but the heat is produced by burning the fuel. You agreed with their fuel consumption number, which is stated at .24 liters per hour (about .06 gallon per hour.) Diesel fuel has 139,000 btus in each gallon, .06 gallon has .06 x 139000 = 8340 btus. Even the Chinese cant make heat from air. I guarantee either the fuel consumption number is wrong, or the heat it produces is wrong, and you said it burned a bit less than a gallon a day, which agrees with 8000 btu. I bet they have a typo and like it because it sounds better. I have seen them do this with electrical stuff, and computer stuff too. I am not saying they like to exaggerate, don't get me wrong.......
its 8kw.. or 27000 BTU. The flame is in a sealed combustion chamber just like the janitrol heaters in lots of other aircraft. I have the scoop on the back of one rad from (mkIV) putting the air straight into the cabin, I also have a 2" hose coming off the other rad into a heat muff and coming into the cabin. I can fly pretty comfortable down to around -30 but only if I keep the RPM pretty high. When I was flying with a buddy who was in his Tcrate I had to pull the RPMs back to around 5200 and it was COLD. At any rate, I am going to order another one for the plane, probably get the 2KW heater for it as that is what we put in a buddies 24' boat and it keeps the cabin nice and toasty on it.
Over kill for an Avid Flyer or Kitfox but worthy of mention is the solution used to fix the tail on Draco. Link here: https://youtu.be/j2WKyra8HBc A small air cylinder with adjustable flow ports on the intake and exhaust could be used to dampen the Avid or Kitfox wheel similar to how the Draco was tamed. We had many hydraulic cylinder designs that used this idea to control flow under various load conditions. Those smaller air cylinders are made of aluminum and are very light and the flow restriction idea works for air just as well as hydraulic fluid. The gas block on an AR-15 is another example of a port being used to control gas flow rate. Many applications use needle valves to make the flow rate adjustable.
Some thoughts about that diesel heater: 1) The heat value makes no sense, at 0.24 Liters per hour max diesel flow, that would be right at 8000 btus. (diesel has 139,000 btu's per gallon, .24 liters is .06 gallons per hour. akflyer confirms this flow when he saw 1 gallon every 24 hours, that is about .05 gal per hour) . The claimed 8000 watts is about 27,000 btus. Even so, I would bet the 8000 btus it really gives out is nice heat. 2) Putting heater, a flame source, in the cabin is near suicide, anything goes wrong and its toast. 3) Putting it right outside (like akflyer's belly pod), with a firewall between it and the cabin would be pretty safe. I have the Avid "stock" heater funnel off the left radiator and it works well down to about 25F (all I've seen so far). If the water temp drops to 145 or 150, the heater falls off too. As a result I block my belly rad off (at 35 deg takeoff, I have it half blocked). Most important was lifting the top cowl and blocking all the area behind the firewall up to the windshield off so the drafts almost stop. I also sealed the door leading edges with stick-on door seal, works well.
Jenki, not the same as split lock or spring. both of those are to keep the fastener from becoming loose. Belleville washers are to keep the connection from coming loose, or to keep constant, predictable pressure on a connection. One use of them is when fastening a wooden propeller, so as the wood expands and contracts with humidity the connection to the hub stays tight. Mark
I will be shaving a lot of weight off it as there is no real need for the long pipe runs etc. Also don't need the muffler on it, just a straight pipe going out. I think the 2KW would be more than enough as these things really do put out some good heat! I could even mount it in a "belly pod" so its all self contained under the plane then just pipe in the heat under the seat.
Well -14 here last few days and think im gettin to b a whimp sometimes about the cold, So decided was time to widen the doors on the Blackfox #0021. So got a 4x8 sheet of lexan and started peelin right side door apart to change lexan and bend up a new center bar. Looks like ill get 1.75" on each side at ur shoulder, elbow, knee. My Bluefox has this done but only 1.5" on each side. Sure makes a lot of difference on the older narrow body Kitfox and probably just as well on the earlie Avid. Ill post more pic as i get them done.
Thank you very much. Better to have more answers than not know what is exactly going on. I need to check it, better say, I will ask manufacturer as I am reaching 200 hours for inspection. I will ask for both, check of caster angle and U-strap settings (resistive damping). It will be the last mandatory inspection (2 years since manufacture date) so they will do complete check. I didn't fly Bristell since 9th September till 5th December now (nearly 3 months) due to starter clutch repair (I am using old ROTAX 912) so I missed good or at least suitable weather here to fly to manufacture. Till the inspection it is still under warranty period and I need to be ready to bring all findings to solve.
No Jenki, not a split lock washer, these are belleville washers. Nested stack increases the pressure available, inverted stack increases the range of operation. Nested and inverted increase both. They are not designed to be tightened down flat. Do an internet search on them. https://www.mcmaster.com/belleville-disc-springs P.S. I missed that others had already answered... had an image added too but it didn't make it.
No, Belleville spring and split lockwasher are two different things. Belleville spring, if laid on a flat surface, is raised on the inside relative to the outside. It's like a shallow cone, with elevation varying with radius only. When compressed, the outer edge is in tension, and the inner edge is in compression. It's a nonlinear "softening" spring; spring rate decreases with deflection towards flat.