jpolenek

As Spodman mentioned, I was selling one last year, but it has been sold. It's pretty easy to make. If you're on the Dragonflylist yahoo group, you can take a look at my write-up in the files section. If you're not a member and want the info, let me know and I can post it for you here. (BTW, I still have 216 feet of 5" carbon tape used for the Dragonfly spar caps, in case your project uses the same material and you're building from scratch.) Joe Polenek

Are you talking about the same thing that's shown in the attched photo? (I'm not there yet, but here's my 2 cents worth...) Since the glass-to-glass bond at the trialing edge is critical to the torsional strength of the wing, I would ensure that the top skin meets the bottom skin for a good strong glass-to-glass bond. My plan is to sand the foam near the trailing edge so it smoothly transitions down and provides for plenty of direct contact between the top and bottom skins. Afterwards, the resulting joggle can be filled ON TOP of the skin. Joe Polenek

MGS charts show postcure temperatures ranging from 50C to 80C (120F-175F). The melt temperature of polyethylene is supposed to be around 100C (212F). So in theory, a poor man's postcure chamber could be constructed using a 6 mil polyethylene vapour barrier bubble and a couple of hair dryers. I've done this in the past when the garage got too cold for epoxy. Garage temperature was 14C (57F) while the temperature inside the enclosure was 40C (104F). Cold garage air was heated by the hair dryers and blown in to inflate the bubble, and simply leaked out where it could. If this was done in a space where ambient temperature is warmer (i.e. room temperature), the enclosure temperature might be in the postcure range. For even hotter enclosure temperature, warm exhaust air can be ducted back into one of the hair dryers, provided that it doesn't over-heat and trip out. Also, the air needs to circulate well to prevent hot spots, on both the part as well as the bubble. (I've tinkered with that and it could be done if set up correctly.) The photos below show two set-ups. The larger one is 6 mil vapour barrier with 2 hair dryers. The smaller one is made of garbage bags and uses one hair dryer. Similar results for both. I've only used this method for "room temperature" cure, and not for actual postcuring, but I intend to give it a whirl when the canard is done. Joe Polenek

In the documentation that comes with the RST antenna kit, Weir says that it's ok to run the coax in the same [1" diameter] channel that runs through the wing for the lighting wires. Is everybody doing that or are builders opting to mill a channel into the surface, and laying the coax closer to the skin? Running it through the existing hole is easier but allows the cable to move around and rub from the vibration. On the other hand, running the coax close to the skin puts it further from the neutral axis in bending and could subject it to compression/tension when the wing flexes, especially if it's microed in place. Which method is better? What about soda straw conduit instead of nylon? Weir mentions soda straws in the gear legs. Joe Polenek

I took my H340 (including my epoxy pump) back to the vendor today. He commented that the hardener in the plastic tubes of the pump definitely "appeared" blue. We pumped a bunch of it out into a cup and compared it to the colour of small transluscent bottles of H340 (green) and H285 (blue) off the shelf. My H340 was definitely the same colour as the other H340 and different from the H285. So I have the right stuff. One thing I had noticed before, which I didn't think twice about at the time, was that when I pumped small sample amounts of the hardener into a cup (the ones that alarmed me), there were a few tiny blue speckles with concentrations of blue colour around them in the hardener, which quickly dissolved when mixed. Also, I had observed at least once, that the hardener sitting stationary in the clear tubes of my pump had areas that were darker/lighter in colour. My conclusion (not knowing exactly how this stuff is manufactured) is that the blue colour that I observed may have been caused by undispersed dye in the H340. If the hardener starts off as a straw (yellow) colour, as some hardeners do, and MGS needs to make it look different, then they would add blue dye to get a green colour. If that blue dye wasn't properly dispersed, and settled to the bottom of the can, then it would be the first thing to be sucked up by the pump tube. I gave the container a few good shakes and pumped it back into itself a few times, and the stuff coming out now looks homogeneous... and green. Joe Polenek

What are you really building???

THANK YOU for posting this. The site has some EXCELLENT runway safety films that every pilot should watch. Joe Polenek

Tom; For what you are thinking of doing, you may want to start by getting the book Composite Basics by Andrew C. Marshall. Joe Polenek

I thought the coordinates are supposed to represent the actual points along the duct. If so, then connecting the dots, and interpolating between them, should give the correct shape. Joe Polenek

Thanks for the offer, but I think I will just take it back to the vendor. I spoke to him on the phone today and he said that it definitely shouldn't be blue. Could be 285 hardener with an H340 label! Joe Polenek

I just bought my first kit of MGS335 and made the same observation described previously in this thread, but with the slow hardener. The can is labelled H340 but the stuff inside is definitely BLUE. I emailed the vendor and he tells me it's actually supposed to be GREEN. (BTW, I did recently pass the Ishihara test for color blindness.) Anybody else seeing blue H340? Joe Polenek

There's something I've been wondering about for years, with regard to these NACA inlet coordinates:What's going on with the y value of 0.307 at x=0.4? When I plot it, it looks too high to produce the smooth curve given in the pictorial. It looks like a value of around y=0.290 would produce a smoother curve. Has anybody else noticed this or have I somehow been plotting it wrong all this time? Joe Polenek

You'd still need to cut through the skin to do the hook-up, but the nylon conduit would allow you to remove the old cable and feed in a new one very easily. The question is: what's the likelyhood of coaxial cable (or its connection points) ever failing and needing repair or replacement? Joe Polenek

I've noticed that everyone buries ther antenna coaxial cable directly into the foam and glasses over it. Is there any chance of the cable needing to be replaced within the life of the plane? If so, why not install nylon tubing, and run the cable inside that? Joe Polenek

Yup. This was a topic of discussion on another canard forum last summer, and here's a great quote by Neverquit that puts it in perspective: "Funny you always think of a big warehouse somewhere instead of some poor slob bagging up a bunch of orders in a garage." Joe Polenek

When modifying the inboard end of FC1 wing section to provide a cavity for aileron controls (Ch.19, Pg.3, Paragraph 2 & Fig.10), is there any down side to cutting it an extra 1/2" or 1" deeper for extra clearance? Joe Polenek

My local fiberglass vendor, who seems to know A LOT about composite materials, says he can supply me the Rutan UND and BID cloths. In the world of auditing, they say "in God we trust, everyone else needs evidence", so I'd like some way to verify that he actually has the right stuff. In the book Composite Basics, Marshall warns about substituting cloths that seem similar, so I want to be sure. Are there any technical specifications available for the Rutan BID and UND cloths, besides just the weight, that I can check to verify that I am purchasing the same (or comparable) product as supplied by ACS or Wicks? Joe Polenek

Not according to ACS's current license agreement. Condition B of the agreement says that the owner cannot allow another party to use the plans to build another plane, and condition C says that the plans cannot be transferred to another party without ACS's prior approval. This illustrates the point that the plans are more than just a bunch of paper that belong to whomever physically possesses them. For them to be useful in terms of copyright compliance, they carry with them the right to be used to build a plane, and through the terms of the license agreement, ASC controls who possesses that right. The purpose of the license agreement is to define the rights & privileges (as well as restrictions) that the owner of the intellectual property is giving to the licensee. In this case, the "value" of the license agreement is the right to build one plane from the plans. Its validity has nothing to do with builder support, or lack thereof. Builder support can be used as leverage, as you pointed out, to get people to abide by the agreement, since it is difficult to enforce. The fact that ACS does not provide builder support does not make the agreement and its rights & limitations any less valid, just less likely to be complied with. See first point above. Ok. Who are you and what have you done with the real Marc Zeitlin??? (The one who always promoted respect for the rights of copyright owners.) () Joe Polenek

IIRC from the Cozy newsletters, Nat had no issue with re-selling of plans as long as there was only one plane per plans#. Does Spruce's policy mean that if plans are re-sold, they will not recognize the purchaser as the new lawful owner of the right to use them? If so then this has some pretty serious copyright implications and effectively kills the resale value of everybody's plans (if they want to do things "above board"). Joe Polenek

Does a wider fuselage require wider (custom) main gear legs, or can the standard gear hoop be used, given that the attach points would still be located at the same Butt Line location and the gear legs would come out of the [wider] fuselage at a slightly different point? Joe Polenek

Me too. Small world. Joe Polenek

Welcome eh! I'm in Guelph, and I just got my plans last summer. It's good to know that there are other builders in the area who are starting the project too. I'm also quite new to the Cozy/EZ world, so feel to PM me if you want to compare newbie notes. If all goes well, we may be comparing Cozy parts in the not-too-distant future. Joe Polenek

Just for shits&giggles I cut some sample pieces of the various Styrofoam types and weighed them to get the density. Here's the summary: Group 1 (4 pieces) Styrofoam Buoyancy Billet purchased around 2004 *** slightly lighter blue colour than Groups 2 & 3 avg. density = 1.95 lb/cu.ft. Group 2 (4 pieces) Styrofoam Buoyancy Billet purchased in 2007 *** identical Product Code and Dow manufacturing plant as Group 1 (printed on billet) avg. density = 1.83 lb/cu.ft. Group 3 (4 pieces) Styrofoam block from Aircraft Spruce *** larger cell size than groups 1 & 2 avg. density = 1.98 lb/cu.ft. The samples were cut to around 1.25" x 1.25" x 14" and I did a deflection test by cantilevering 12" of it and putting a 0.3920 weight (my measuring tape) at the end. The deflection ranged from 3/8" to 7/16" without any correlation to sample group, so they seem to have a similar modulus of elasticity. So it turns out that my BB foam may be slightly lower in density than the ACS product. (I say "may be" because of the statistical (in-)significance of such a small sample size). Therefore, weight shouldn't be a concern, but the potential effects of the smaller cell size on peel strength may still exist. Has anybody else verified the density of their Styrofoam (Buoyancy Billets or ACS blocks)? Joe Polenek

THANK YOU!!! :banana: :banana: I would have used more dancing bananas, but that's all that the program would allow. (Can you tell I'm relieved? ) Joe Polenek

Has anyone successfully used the 2.0 lb/cu.ft. buoyancy billet with the smaller cell size and can reassure me that it is OK??? Having cut a good portion of my cores using the buoyancy billets, I'm having some serious doubts about the suitability of the material and could use some reassurance (if it is warranted). When I compare the two foams, the product from ACS feels "crunchier" when I crush it, snap it or drive nails into it to attach templates. When I take similar sized slivers of each and bend them, they seem to be the same, but for some reason, the ACS material just feels stiffer when I try to crush it. It's hard to tell how much of that is just perception becuse of the different cell size. Part of me is considering cutting my losses and scrapping it all out and doing the cores over again with the plans-prescribed material from ACS. On the other hand, I'd hate to waste all that time and money if it's not necessary. Any advise would be greatly appreciated. Joe Polenek