Jon Matcho

Yes, I was but then switched to a Permagrit Tungsten Carbide cutting wheel. The only problem there was the Dremel's power it seemed. I do think a thinner wheel like the 542 you mention would do a better job. I may also replace the bearings/brushes on my Dremel. I snapped my shoestring budget for the month -- and need to make do with the current vat of elbow grease I have. Still, I can probably squeak-in that 542 blade. Thanks for the feedback and help! I will develop the routine sooner or later.

There's also the Canard Aviators group, which is for all canard aircraft, and many flyers.

Today was the day I was NOT going to work on my bulkheads (can't call it a plane just yet). Unfortunately, "today" began w/2.5 hours of work at the wee hours of the morning, but that didn't count for "today" because it began yesterday. In the morning, as I was leaving for work, I took a look at my layups. Ooo... the "chewing gum stage". I couldn't resist pulling out a razor knife and cutting away at excess glass. Here, I found cutting these layups was awful. 2-5 plys total, and thick tacky epoxy. "There's got to be a better way", I thought. Tonight, I KNEW I wasn't going to work on the plane. But as I was putting down some mouse traps for my late night coworkers, I heard a faint noise... I got closer to the noise... "cut me, sand me." My bulkhead was calling me! So out came the razor saw... too much work. Next up, the Dremel w/cut-off wheel. That started melting & burning the epoxy (nasty stink), and then I remembered I had a PermaGrit cut-off wheel! That was heavier, and the Dremel was practically brought to a halt at times and getting rather hot. I think I should have used the lesser diameter PermaGrit wheel, or something w/more POWER. After battling with the tools I had for a while, I made a mental note to check Jerry Schneider's "must have" tool page. Which tool first? Hmmm... I want the lot!

Pete, I suggest you join the COZY mail list available at www.cozybuilders.org, where the definitive list of COZY builders is maintained. Mailing information is required at sign-up, and once you're signed up you can find all the people plotted on this map. Other than that, feel free to strike up some discussion here. It feels like you're in the next room from my end.

Over $37 for a 2' x 4' sheet. I rationalized that into $0.03 per square inch -- cheap! Thanks Jerry, I'll do just that -- concave side down and glass the convex side with weights.

Welcome! While I have no experience or firsthand knowledge of the E-Racer, I am a fan. Since this thread's subect is Opinions?, I figure I'm allowed to reply. You should try to contact E-Racer members here directly. Do an Advanced Member Search for 'Racer' as the Plane Type (to catch 'E-Racer' and 'ERacer'). I did that and found 5 members. Personally, I chose the Cozy because of its robust builder self-support community. There's also the rear seat/baggage room of the Cozy. If you want retracts, there are a number of current builders breaking ground in that area as well. You can find a current discussion on retracts here. Regardless of your decision, you're more than welcome to post here (just pick a canard, any canard ) and join the discussion.

I should have taken that bet. I was passed to "Don the Wood Guy" who explained to me, "plywood will warp if there is any humidity around -- it's a fact of life with plywood." Knowing that it has been raining on and off for the past few weeks, I couldn't argue with that. It's also a relatively small warp, so I'm not worried about being able to get it to cure flat.

I thought about this topic while laying up my F28 and F22 bulkheads this weekend. I have come to realize that major factors for part weights must involve technique, particularly: Micro-slurry density (affects how much epoxy soaks into the foam) Micro-slurry partial cure (if it's wet, it may dilute a bit with the incoming epoxy; it it's tacky, it may stay where it's at) Optional non-glass coverings (peel ply and/or plastic) Squeegee techniques (from light-to-hard pressures) Personally, I've found that I like to keep my layups on the damp-wet side, apply plastic and squeegee fairly agressively. Ideally, I will pull the plastic off and let cure, unless the part needs to cure flat while weighed down. Pulling the plastic at layup-time lifts a residual amount of epoxy from the fabric voids, as well as allowing inspection for areas that have become too dry. If too dry, I just stipple a small amount of additional epoxy. I do think that using peel ply and/or plastic reduces weight over glass alone, but suspect a small weight advantage of using plastic and peeling off at layup-time. Which, however, isn't always possible when parts need to be weighed down -- use peel ply AND plastic, with the plastic here functioning as a non-stick surface. If it sounds like I know what I'm talking about -- I apologize in advance. I don't.

I'm thinking I may be overdoing things a bit... While watching my girls around a backyard fire last weekend, it occurred to me that S'mores are a composite structure! Stirring my coffee this morning, I took extra care to get all the resin off of the sides -- whoops, I meant sugar! Staying up until 3:00am, sleeping until 7:00am, and needing more resin-laced coffee to function. If my kids were acting like this, I think I'd have a hard time NOT accusing them of being on drugs.

After getting through my first few foam pieces, I have become an expert foam cutter. Tool tips: Dremel (cut-off wheel & cutting bit), Permagrit sanding blocks, and a round and wide file (or another Permagrit tool). Forget the coping saw. I made my F28 bulkhead out of 2 spare foam pieces and of the shorter height. I'm not sure whether I'm going to keep it this way or make another one out of the foam I saved.

I found the firewall plywood I received from Wicks not to be what I expected -- aircraft-grade flat. Instead, it's warped into an odd concave shape (see attached). When sitting on one side, two far corners lift by 3/4". When flipped on the other side, the shorter edges lift in the middle by 1/8". I am thinking that when I cut the plywood longways it will relieve some of this tension. Also, it doesn't take much weight at all to push the piece down flat when on the one side. That being the case, I am thinking to leave it as-is, glass, and let cure with some weight on the top. Thoughts?

Boy do I wish my seatback looked like that!

Agreed. I should have indicated my statement to be my opinion (as well as Burt Rutan's), and that I'm in the "spends it" camp. How's this for the controlled experiment: foam, glass, squeegee treatment foam, glass, squeegee treatment, peel ply treatment foam, glass, squeegee treatment, pressure bag treatment foam, glass, squeegee treatment, peel ply treatment, pressure bag treatment foam, glass, squeegee treatment, vacuum bag treatment foam, glass, squeegee treatment, best non-vacuum bag treatment, sandblast treatment Controls would be a 12" x 12" foam piece, micro the foam (same volume for each piece), 1-ply of UNI glass, same epoxy type (with volumes driven by the needs for each experiment #), pieces trimmed and cut to exact dimensions. Ideally the pieces would be made larger to get a better contrast of weights, but 12" x 12" is all I could afford throwing at this right now (unless I make shelves for that fiberglass bookcase I designed...). Regardless, I cannot perform tests 5-6, so I'd gladly let someone else do this in order to prove Marc wrong. In the end, proving Peel Ply = Added Weight is not on my top list of priorities and I may do as everyone else has done in the past -- go forward with what I feel is the best technique to produce the lightest parts. With all that said, I'm afraid to weight my seatback bulkhead tonight and compare against the Cozy Builders Web stats.

You wouldn't be able to use the Plastic Pressure Bagging technique here, but you might be able to use peel ply in thin strips. In either case, it may be best not to use either and just do a little sanding. Chances are you won't need peel ply in these areas, and your only bagging option would be Vacuum Bagging. You could consider sandblasting. Peel ply also adds weight, and so I am actually considering peel plying ONLY the seams, and hand-sanding where necessary (or lightly sand blasting with this dream machine). With the little experience I have right now, I feel the anti-sanding rhetoric may be a bit outdated. Get yourself a set of the sanding tools from www.permagrit.com, available everywhere, and see what I mean. They have every shape imagineable, are indestructible and have so far made sanding a non-issue for me. Of course, these are my "famous last words".

No doubt this is important -- I certainly could have done more in this area, and will, but realize now that everything you read about does indeed have a critical path. Some are obvious, such as the hotwire tool, but others are not until you start mixing epoxy. I'm going to revisit shop setup now and again, but keep going with building 80/20, then 90/10, and then 99/01. Keep focused, and you WILL get your wishes. Those are the same 3 things everyone else had to contend with, although some easier than others. Look at Andrew here -- building a shop on a mountainside? So guys, I hope to be reading about your own progress soon. Speaking of progress, I was hoping to get an update from "Builder X", but no such luck. John seems so far ahead at Chapter 6+ ... I shall endeavor to progress as well as he. I am also the proud owner of a 90% complete Seatback Bulkhead. I thought I was 100% complete, until I remembered the last 2 sentences for this item in the plans -- cut 3 rectangles into the bulkhead, one of which being the map pocket, which can be made larger by going with the electric air brake (I think). I did manage to make some more small mistakes with glassing the other side, which I promise never to do again. Turned out that the excess epoxy I squeegeed off and "went away" just dripped to the bottom side. See attached.

We could setup a community design project, similar to the premise at www.openaero.org where the vision is for a group to design entire planes. The same concepts apply for aggressive modifications such as the door we're talking about here. Once all is done, we could sell the plans to other builders to recoup our upfront costs. The way I see a prototype coming together is: Get an engineer involved and establish the design Retrofit the design into a project that has ONLY finished the main fuselage (Chapter 7) Document plan changes, put on shelf Complete build of aircraft Prove air worthiness Offer plans to others A retrofit into an existing fuselage strikes me as the best option, potentially becoming the standard for how such a modification would be performed. There are many structural options, and to name a few: Overhead support structure Velocity-like center spar Internal support structure (similar to #1, but built into the fuselage front itself) Localized structural reinforcement Design criteria to consider: Must work with absolutely minimal risk Must be minimalistic in design -- we're not designing an entire Velocity Must be reproduceable for other Cozy builders This would be a big project to consider, but one that I am very interested in.

Additional specs can be found at the Dyke Builders Network, which are slightly more conservative. I think this is where the community factor comes into play. With the Cozy, you have so many more information sources to choose from that it's much easier to gain a level of confidence on such things. Personally I don't get the same tingle-up-my-spine feeling with this plane as I do when I see a canard shape in the air, on the ground, on the Web, in print, or in my dreams. Still, a very interesting feature of the Delta is that the wings can be stowed on top of itself and trailored home by car -- without a trailer. That might be true, but we all know that Duck Dodgers, Spaceman Spiff, and Marvin the Martian would all pick the Cozy.

It was Dust that said that. So let's get to designing our doors. This can be done, in exchange for some weight. In the meantime, highlight all the safety features to further increase your SAF metric. You could explain that the cabin was modeled after the same technology used in many of the Niagra Fall's barrel successes. Nah, throw them in the back like ballast. I personally don't think back seat access should be a major concern. If that's your entire history on the subject, chances are you'll be fine -- just take all the possible precautions -- gloves, no exposed skin, and good masks. The data shows these planes last very long. This would be a good question to ask on the C-A list. No/little wood is good -- no rot, as well as little metal to oxidize. The structure is actually the last thing I'm worried about failing. If they're nearby and convenient, then "why not?" I chose to visit builder projects at a few citys I happened to be traveling to, which is great even if you just look around. Call ahead and you can offer to help someone already underway -- I would have easily taken an epoxy mixer. Finally, order the practice kit from Wicks or ACS&S and you'll see firsthand how EZ it really is. Either visits, classes, the practice kit, or Chapter 3 in the plans is all you really need to get going. "Just do it."

Well "X", so far they're the only critics I have, which is both a good and bad thing. Feel free to let me have it though as I "progress". I visited a handful of builders and flyers, as well as read a good portion of the Internet . I researched my shop, materials, plans, space, and 100 other considerations to be the best builder possible. Even after reading Jack Lambie's book, Composite Construction for Homebuilt Aircraft I still managed to exotherm the 5-minute epoxy and make the mistakes mentioned here. The moral of this story? "Until you begin, you don't know Jack." Not sure how well that translates to Australian. So John, what have you done since that night? Spod, did you get the info kit or plans? I forget. Tell us!

Ron, you know my vote. I'll leave you to decide the quantitative factors, but I must say that the Cozy is 38 units more cool than the Dyke Delta in my book. Popularity Next to RVs and Lancairs, I believe the Rutan canard design to be the most popular and widely supported out there. This link at the Airventure site had this to say about the 2003 attendance: Builder Support & CommunityWith the Cozy, you have several support sources competing for your attention. For the Dyke Delta, you might have trouble finding another person at or near the same stage you'll be at. Even if Aircraft Spruce shut down, you'd be able to finish the plane. Time-tested Metrics With the Cozy, you have an excellent reference from many existing builders and flyers for how long things take, what options exist, and what they would do differently (if anything). Composite Material Allergy Regardless of the plane you decide, you do want to be careful as both use fiberglass. I do think that the community, as a whole, has become much wiser in the ways of preventative measures. I have 4 different types of gloves and 2 different respirators. You can put yourself in a bubble if need be -- one of those white Tyvek suits. If you can't handle epoxy, foam, and fiberglass, consider an RV-10 (but I hope you'll manage). Individuality There are so many proven and half-baked ideas out there that you can turn into your own -- the Hofacker Cozy Mk IV. Some of these designs have virtually become unofficial "stock" options. I recall these factors at the time: Nat Puffer is alive and well (now 'Aircraft Spruce is a solid business') ACS&S AND WICKs are providing "kits" A fairly robust aftermarket exists www.cozybuilders.org the COZY e-mail list and the Canard Zone Forums (this forum) Builder Web sites Other forums and e-mail lists Now that I'm building, I'd move the items relating to builder sites and community lists/forums higher up in importance. Hope this helps. Here's another thread on this forum discussing the RV-10 vs. the Cozy Mk IV that might also help.

Ready or not, I decided that I had to officially begin building my Cozy in May 2004. With just a few days left, and just a few hours between picnics, I managed some real progress. Here are some highlights... 1) On Saturday I began the process of measuring twice before cutting once. This seemed to expand exponentially, as I compared the full-size Cozy drawings to the smaller sized original M drawings. I got distracted with finding the full-sized drawings of the Instrument Panel bulkhead were 1/8" larger left-to-right, and 0.04375" larger top-to-bottom than their original-sized counterparts. I pulled the necessary materials from their shipping containers. After about an hour, I convinced myself that I was looking at the right shade of blue foam. I had to cut the fun short to help my brother-in-law dig fence posts, but at least he owes me now. 2) On Sunday I remembered I had thought about widening the fuselage way back. Why? Because it would be bigger. Bigger = better. With this in mind to finalize, I joined two 2' x 4' sheets of blue foam. I then left for 2 picnics, wondering about the seatback width and whether I'd be able to use the full-sized templates I just received. 3) On Monday I re-read all the info I could find on widening the fuselage. I apparently forgot about the increased drag factor, which I found not at all appealing. I'd rather be Fast and Cozy than Slow and Comfy. I rejected the widening idea (with Marc Z.'s help) and cut a 42" x 28.8" piece of blue foam. I also decided to use the full-sized templates -- they're close enough and I am NOT tracing (so I thought). I soon found that neither the full-sized plans nor the originals provided all templates for the seatback -- you have to make some mirror images. So I just traced the back sides of what I cut from the full-sized prints. How ironic -- pay extra $ to avoid tracing, and I still end up tracing. I micro'd, cut cloth, epoxied, and did everything as I thought I would, but... I made 2 mistakes: a) I overlapped one joint of UNI glass. The plans state that "this is unnecessary", so I assume it's not going to lead to a catastrophic failure. I promise not to do it again. b) I used the Plastic Pressure Bagging technique and was happy with the the results. HOWEVER, after I had walked away from the layup for just 1 minute and returned, I found the 6mil plastic had ballooned in spots. "Yikes!", I thought. I forgot the halogen lamp was still pointing down on the layup. I quickly pulled it off and re-stippled the trouble areas back into shape. No big deal in terms of air bubbles, just some movement of epoxy underneath. 30 minutes later, after washing up, I realized that when pulling the plastic off it pulled the 2nd corner piece of glass off. So more epoxy and glass and all was back to normal there -- better so, since now I put this UNI butt up against the other piece. I received some satisfaction by being able to cut most of the edge at the "chewing gum" stage. So there you have it... 25% done with Chapter 4, Page 1. Feedback is appreciated -- I was worried that I would have to do this piece over, but now think (and hope) not. I should also probably get me a Web site if I'm going to babble like this.

The official report from NTSB can be found here.

Or "just" one Grand Champion Cozy Mk IV!

Here's an interesting thread on the discussion of these items. To get started with building bulkheads, I bought a 3' x 4' sheet of 3/4" plywood. You can put this on anything and have a good work surface. For tables, I am seriously considering the design from EAA Chapter 1000, but until then, I have my 3x4 sheet. Bulkheads, here we come!

Interesting technique... definitely something to consider. I wonder if he could finish a per-plans Cozy before he finishes his aircar. The poor guy wrote he has 4,500 hours into his project. I like building, but not that much.