chasingmars

This has been much discussed back and forth and is worth a little archive diving both on the groups and on the cozy list archive. Without opening a can of worms, I wouldn't use aluminium in my firewall over the steel option even if my country's (Canada, not U.S.) regulatory body for amateur builts would give me my COA with it, which I gather they won't.

Constant wear immersion suits can be less than comfortable for long periods of time, however, it's my understanding this is how military overwater flights are done for some aircraft (Our Sea Kings here in Canada being somewhat older than most of their Pilots I gather work this way), at any rate, a dry suit won't do that much good if you're not in it when you ditch. Depending on the water temperature, you can become ineffective very quickly in cold water. One should be sufficient, modern 406MHz systems can get your position to a rescue centre within about 15 minutes More for routine operations on the trek than for ditching use I think. Proteins and such take a lot of water to digest, if you don't have lots of water, you need all-carbohydrate survival rations, that you can eat to subsist without dehydrating yourself. You can fish for protiens if you need to, and you have water (you need fresh water far more than food in the short to medium term) Moreover, a watermaker pump, so you can make water from seawater. These days, some rafts are using a lightweight long orange plastic streamer that you can throw behind instead of the sea dye marker, which are limited in how long they last. At least one type of these are day/night with a flare end and a smoke end Great way to make sure you never get to ditching because a rightfully indignant nation confiscates your plane for smuggling a weapon. Missing: Floatation vest A knife, preferably also a raft knife (sharp edge inside for cutting cords but can't cut the raft), ideally the raft knife is in a float vest pocket. Signalling mirror (has a hole in the centre for sighting what you want to signal) and whistle aformentioned reverse osmosis pump and/or solar still (one takes effort, but that's not necessarily bad in a survival situation, the second won't work if cloudy but if it's sunny it's free water) Insect repellant (not all emergency ditching is overwater) Sunscreen (exposure kills) "Space" blanket (doubles as sunshade/rainwater collector) Sutureing thread and needle, topical antibiotic, copies of prescriptions as nec etc in the first aid kit Iodine tabs (freshwater purification) Light Neoprene gloves so you can have some use of fingers in cold water. Hand-crank or solar recharged or long life battery LED flashlight Touque to reduce heat loss through the head, one that will be warm even wet spool of high strength line Some method of attaching your raft to your life preserver with a line Anti-nausea pills (seasickness can kill your through dehydration) monocular, waterproof Fishing line/hooks isn't a maybe but a must, in case your ELT doesn't do it's job or gets separated from you you will need food, and you can make snares for small animals on land from same. Much of your camping gear becomes survival gear if the time comes (tent, sleeping bag, etc) A good land and sea survival course - knowing what to do is vital (even for something as simple as on rescue letting the metal part of the basket lowered from a helicopter touch water before touching it, to avoid shock from rotor static discharge, and little things like that), also a survival reference (in waterproof container), especially with what is edible/poisonous (some reef fish for example are prone to a toxin they tolerate but that will paralyse you) and first aide. Probably a number of other things I've forgotten but that good research will turn up. All sea ditching stuff packed in a floating pack, linked by line to the a/c (with the raft knife accessable so you can cut the line if the plane starts to sink/catch fire, etc) with a ring on the line near the a/c end of it so you can hang on with your arms when your hands are too cold to work so you don't loose it after you cut the line to the a/c.

I have to agree that a web site can take a lot of time. What I do is just write in a word processor, add my pictures and then crank out a PDF file which I can just upload and link in. That way I don't spend a lot of time messing around with HTML, although I gather that no one does much of this by hand anymore and just uses an editor which I guess is the same. I let my pictrues pile up for a while, then write when I'm travelling or somesuch so that it's not "in competition" with build time. The pictures make for a pretty good memory jog as long as I haven't left it too long. Best advice is just to build and not to put too much of your plane building efforts into things that don't make plane bits.

Well, only if you have similar acceleration vectors (or ones in different directions)... that's the point of the big rainbow arc you mentioned, to get you and the plane both on an approximately free fall trajectory. In level flight, the plane is like the ground, if you jump, you'll come back down on it shortly thereafter (approximately, with wind and all that pushing you around, and level flight being not exactly rock solid after you let go)... so, if your bail proceedure involves jumping straight up, ask yourself if standing in the cockpit, you could do a standing high jump over the prop, cause in level flight, that's what you have to do. Unless you put the plane in a dive. Otherwise I think trying to go over the prop is asking to be mulched. I remember reading at one time something about Dick Rutan saying his proceedure is to go under the strake and down, which strikes me as better. Also that he wouldn't want to try it.

I found that the corners were way off, not even close to the right shape, and I needed to reshape them to match the fuselage sides, even though both areas were to plans and built pretty accurately, I think. My seat pocket area though I found lined up very well, I was worried because I missed the part about cutting it undersize and then matching it up later, so I was concerned about it being off centre, but it turned out to be a matched fit - so for here I think the plans are well drawn. The corners though, I think the projection was messed up. I agree, wouldn't bother much on the corners till later, then just cut them to fit your sides.

Eats, shoots and leaves?

Sometimes my brain accidentally spits out nonsense... hmmm... I meant: "As altitude changes the true airspeed is proportional to the inverse of the square root of DENSITY." (to a rough first order approximation)

Looking only at first order effects, power scales roughly to the cube of velocity, and linearly with effective flat plate area at a given altitude. As altitude changes the true airspeed is proportional to the inverse of the square root of drag. So, that gives some basics to frame your question. Talking "advertised" numbers, the Cozy "advertised" cruise is 220mph at 8000 feet on 75% of 180hp. Here it gets a 1000nm range (again, advertised) on about 52 gallons of 100LL. This is about 190mph IAS. So, changing nothing but power, doing whatever mods are needed to ensure the aircraft is safe at 300mph (which is above the published Vne so this is non-trivial) and assuming you can do this somehow magically without any weight impact, to get 300mph under the same conditions would need about two and a half times the power for the ~35% speed increase. That means, powerwise, about a 460hp engine... remember, if you add weight, you need even more power. Too bad the Innodyne is fuel hungry vapourware. You have about an hour or so fuel for a PT6A though! Drag reduction is the best way to increase speed on most planes though... so... make all the antennas internal? Already done. Slippery glass airframe? Already done, etc... A whole new wing design and foil shape taking into account a section with a drag bucket in the right spot for the Cl you're planning on (just over half the cruise Cl of a Cozy) might shave a few hp off that figure, which is a major redesign, probably one of a dozen to do this... and no more weight or it takes more power. In short, gains of knots to a couple tens of knots are acheivable it seems, but the shear nature of drag makes the kind of gains in speed you're talking about very difficult to acheive if they aren't designed in from the drawing board... at least, at a given altitude, but I don't think the Columbias are turning 300mph on the deck Me, I'll take being the second fastest on the ramp, with a third of the operating costs. Easiest (for relative values of "easy") way to go faster if you want big speed gains, install oxygen and a turbo'd engine, and fly higher. If your turbo engine can hold 160hp to 25,000 feet (no mean feat to start with), and you're confident in your engineering ability to manage the Vne and flutter issues (and I'm not sure I'd be too quick to nod on that one), then ingnoring a few effects that will sap some speed (prop effectiveness, etc) at 25,000 feet you're starting to get close to that 300mph TAS number.

More evidence that it's elves doing the real work! While he's at the beach no less! In December! And happy (belated) birthday Chrissi!

Actually, exactly the same thing can be said for canards. While I love them, and this is a canard forum, it would be wise for us to remember that sometimes that's a partly emotive decision. There are many who sing the praises of canard efficiency when it comes to having two lifting surfaces and no downforce surface, but notably abscent is rational discussion of the true magnitude of the downforce in cruise on conventional aircraft, which is less than usually cited in comparisons, and moreover, the necessary decalage for stall resistance does negative things to the ability of the main wing to generate maximum lift, and without heroic measures, prevents use of flaps, generating high landing speeds in turn making designs possibly carry more wing area than they might otherwise need. The distribution of lift with the canard makes it more difficult to get a high aircraft efficiency factor / best span loading distribution and this is complicated by the relatively higher coefficient of lift the canard operates at relative to the main wing to maintain that stall resistance. Yes, there are advantages, mostly in medium-high (relative to piston GA a/c) speed cruise and stall resistance that are constrained to relatively long paved runways and are light enough that sophisticated flap systems aren't economic in the first place (i.e. the Cozy/Long mission). There are also disadvantages, and, as is fairly unsurprising given the way aerodynamics tends to work, overall efficiency is close to a wash, and if it weren't, a 3-surface (hey, back on topic, the subject design is a 3-surface! ) might have both beat by a smidge anyhow due to the ability to independantly minimize trim drag across a range of airspeeds. As Heinlein said best: TANSTAAFL. (http://en.wikipedia.org/wiki/TANSTAAFL)

It's amazing what 2 minutes and google can turn up... I'm wrong, what I was remembering is the "mandatory" replacement of aluminium control system components behind the firewall. What you are remembering is true, it's in CP #25 I'd still not put in an Aluminium firewall, but that's just me (and, of some import to me anyhow, Transport Canada, who apparently won't give me a special airworthiness cert if I were to) ... and, um... asbestos? There are Longs out there with Asbestos firewalls?!

I wouldn't... I had thought, from memory that it was the other way round, that RAF had put something out saying that it should be stainless and not aluminium for the Longs etc... on the Cozy I gather it's remained aluminium in the plans. But to me, I think, despite the fact that it's supposed to be the fibrefrax that provides the heat shield, it should be stainless or titanium for a firewall.

I did just this before I started, the 6 ply panel, slightly larger than the test panel requirement so I could chuck my edges. I'm not sure if this was a vac bag or hand layup, but I'm fairly sure it was hand layup. I layup up a single piece so that I wouldn't have as much variability as doing two separate ones. I put peel ply across half of the part, and after cure, cut it in half along that line. I put the two pieces together and table saw'd them to matching side, removing the edges. I then weighed each on my gram scale. Exactly the same result. Wish I'd had a scale that went to 0.1g, but I don't, still, any difference is pretty negligible from what I could tell. For what it's worth, I don't thing peel ply changes weight much either way. I peel ply everything.

There have been delta types, and even flying wings, with flaps of a fashion, the key concern is, as you said, the pitch moment they induce. The Me263 Komet from WWII had a type of trailing edge split flap that produced very little moment change on the flying wing for example. With the canard however, bear in mind that you're trying to reduce stall speed. If you are intending to keep the canard-first stall characteristics (and if not, you have to tackle the deep stall recovery issue), then flaps, due to causing a nose down moment on the main wing, actually increase canard loading for any given angle of attack. This means you will actually need a somewhat greater elevator deflection to keep the canard flying, and this will actually make your canard stall a bit earlier as you run out of elevator deflection, meaning the flaps are effectively useless, unless you also flap the canard. The Roncz canard elevator is essentially a flap, so one way to do this might be to allow increased elevator deflection with flaps extended. Not the simpliest stability problem, but theoretically possible. Slats could help, as they tend to simply extend the lift/AoA curve to a higher AoA at stall (unlike flaps which tend to shift the whole curve up), but again, you'd have to make sure that the canard could remain flying at the higher AoA to ensure it doesn't become the limiting factor. Interestingly, this implies that fixed slats on the main wing could be a possible way to deal with deep stall by ensuring lots of AoA margin on the main wing but for a Cozy/Long type aircraft the performance penalty in drag is probably untenable. This assumes you're using the canard as a proper full flight surface. Many canards on big delta wing style military aircraft use the canards basically as a control surface and to modify the vorticies over the main wing (like LEXs do), and so are a different kettle of fish.

Price of MGS has ballooned recently, to a far greater degree than the rise in feedstock prices probably warrent. My 6-gal batch about a year ago cost me 505$Cdn at about an 85cent dollar. My latest was near 800-ish at a dollar that was approaching parity. My vendor indicated that he thinks MGS wants to wean people off the 285 and onto their other products so they can move away from some of the components in 285/287 hardener, and so are pricing it accordingly, but I'm not so sure as 335's gone up quite a bit too.

As much as I respect Nat for the work that he did upsizing the Long to the Cozy, and without taking away from how good an aircraft the Cozy is, this document always makes the aerodynamicist in me cringe. The assumptions that form the basis of the analysis are pretty arbitrarily chosen, and I'd say are fairly suspect - especially, I think, the idea that a conventional aircraft carries as much downforce on it's tail as a percentage of gross weight as the canard carries lift, this seems pretty absurd to me, yet is the basis for a lot of the argument. It's also pretty selective about what induced drag effects to talk about, highlighting the effect of the winglets without discussing the negative that the canard brings to creating a rather less than ideal spanwise lift distribution. There are other problems with it, but really, it's a bit of a straw man attack, the conventional design isn't anywhere near as bad from and efficiency perspective, and the canard has compromises in efficiency not mentioned. Both approaches can make great aircraft. In the Army, up here anyways, it's what we call "situating the estimate" (a play on "estimating the situation")

Something fairly similar here, except I think we run the order in reverse, the inspection process is delegated by the Minister of Transport to an organization called MD-RA, you pay them a fee for the inspection (which despite being quite high just covers "administrative costs") and they send out a volunteer, who gets paid only travel costs (which are again damn expensive if he doesn't live nearby). If you reach loggerheads with him, you theoretically can go to Transport Canada, and get them to rule, you don't have to go through MD-RA, but I gather that once you do so, costs go through the roof, so I don't think it's really done in practice, except perhaps up North or whereever that TC would be cheaper than the travel costs, maybe. At least, that's what I've gathered so far. Others have more experience with MD-RA than me no doubt. All I know it that I filed my "intent to build" about 18 months ago, and when I log in, it still tells me that the status is "Pending" or somesuch And COPA says that this way of doing things is far more responsive than Transport Canada was! On the other hand, I gather from chatting with people that the actual MD-RA volunteers are pretty reasonable, they are all completed-builders themselves apparently.

Looks like the plans method is fairly straightforward. While the idea of Feining off an experiment gone wrong doesn't appeal (and that's an understatement!) I may try it anyhow, just out of curiousity, once I can completely assure myself that I'd be getting the same strength at no more weight. One thing I was thinking about with going with a braid is that because it's continuous, it should be stronger (plans is only 4 plies thick at nose and trailing edge) but this is probably a pretty moot distinction as it's clearly a layup designed to improve stiffness characteristics and strength is not the driving factor here. Marc, when you mention substantial variation in cross section, it varies from about 2/3 nominal to nominal braid diameter, I wouldn't have thought that too bad... I think next time I'm at my supplier I'll pick up a small amount to play with and see how it wets out and lays over some scrap PU or something before making up my mind. Better to get an idea of what I'm working with before trying something like this I think. Thanks all for the feedback so far.

That line of argument might work... the item in question is: Or, it might not. I'm keeping an eye out for 18 mil titanium sheet in a large enough piece

Wow, when did this place get so high school? Whether the comments were made in fun or serious lack of tact and good graces, I think it's a good thing that people ask those questions of W&B, cabin size, etc associated with the aircraft they're considering, and if the first thing we do is criticize, then how many lurkers could be builders could be flyers do we risk alienating? We all know there aren't many FAA standard 160-pounders anymore, so why not just accept that and deal with the issues of how we fit into our aircraft?

Hello all. I got one of those "bright ideas" so before I go mess something up, I figured I'd post and see if there's good reason not to do it... While I'm still plodding throught chapter 7, I got my LG components the other day, so I've been reading ahead a bit in the plans to see whats involved. I've read that chapter nine involves a huge number of hours, and I'm looking to find ways to change things to take longe... um... I mean, save some labour. Anyhow, I was looking at the first part, where one lays offset cut UNI, 8 layers in all, from two directions, in pieces, without getting the fibres bent This is to provide additional torsional strength to the gear. I'm not entirely sure why 35 degrees was chosen, and why the angle is biased towards the directionality of the S-glass hoop, given that for a tubular skin in torsion, the principle stresses would be at +/- 45 degrees (skin in shear), and the addition of the bending of the hoop would offset this in different directions on top and bottom as the top's in combined shear/compression with the bottom in combined shear/tension. Maybe I'm missing something and Marc or someone else with a better stuctures background than I can fill me in. Anyhow, the reason this is on my mind is that I noticed that the gear circumference tailors fairly well to that of 4" diameter braided sleeve, which is pretty commonly available these days. At the fattest parts, the gear is about 12-1/2 to 12-3/4 around, which would have a 4" sleeve at just about 45 degree bias, then as it tapers it would pass through 35 degrees about 2/3s to the wheel (10.2" circumference) tapering to about 27 degrees at the strut end and on the other side about 24 degrees through the centre where it necks down. So what I was thinking is, since I figure it's probably a lot easier to get straight consistant fibres by smoothing down a braided tube over the landing gear, is there any glaring reason why this shouldn't work if I run the numbers to account for the glass strength of the braid and account for the variation in angle? I haven't done all the math yet, but something like 3 layers of 24oz braid should be easier that the 13 pieces of UNI? What do the folks that did it the plans way think of the plans process, is it as much of a bear as I'm thinking it will be, or does it just sound complicated and is easier in practice? Has anyone worked with braid before, from a manufacturing standpoint, is what I'm suggesting workable or is there something I haven't considered? Are there advantages to more layer of lighter braid? Should I put a finishing layer or interlayers of lighter braid between heavier keep the resin weight down? And from a stuctural standpoint, am I missing anything significant here? From a weight perspective, I don't mind a *little* extra glass to make up for the change in approach, as I'm much more easily able to vac bag a braided LG hoop than a plans done one (the supports make it more complicated) and a good vac bag here can probably save 1-2 pounds given that there's about 6 sq yards of glass in this wrap. Anyhow, thoughts? I want to have a nice warm fuzzy before trying it as it's an awfully expensive piece to mess up. your feedback is appreciated!

Regardless of whether the DAR/whomever has the legal authority to *make* him take it out (and not knowing exactly what he did use), if it's solid core or PVC insulated or whatever, it's a awfully good idea to do so, isn't it? I'm not sure exactly what your rules are in the States, I know there's more flexibility, here, the inspector can say "that doesn't meet this or that design practice" and you have to correct it (or at least, show that your method is equal or better), I gather. For example, my firewall can't be plans aluminium, I'm told.

The airplane is interesting? :D Regrets to francophiles... but at the end of the day it's true, we retain what we find most fascinating. I'm sure if someone unearthed my high-school notebooks (and probably uni too) there's be more doodles of airplanes in the margins than actual notes! Wait a sec... six years of first year French??! Heh, I did first year Calculus a few times over but six times?

I don't think there's many languages with only past present future, I think that when we're native speakers we don't learn the grammer by rules but by habit, so we use all the tenses of our native language without realizing it. When I was learning french, francophones would tell me things like "oh, we don't really use imparfait", or "that's just an archaic form", but they *were* using it, they just didn't realize it. They'd say "there's just present, passe compose, and futur" and miss the fact that they were using, out of habit, imparfait, plus-que-parfait, subjonctif, conditional, etc, etc,... Who remembers grade school grammer for their native language, we just speak it! But you couldn't get by with just three tenses I don't think. (Oh, and yes, I know subjutive isn't really a tense but a mood and all that, but really, it amounts to the same thing. Mood and voice and forms oh my! Makes me glad I chose to study something simple like engineering, instead of languages, but wow, it's amazing that the average person does all this transparently) As for irregularity, there I'll agree with you, english is terribly irregular. I wish it were otherwise! (< look, english subjunctive! yet most will insist the subjunctive doesn't exist in english! )

I bought the plans, then a while later, after really making sure I wanted to do this, materials... the plans are your penny ante, make sure you're sure before getting into it for thousands. I buy glass by the roll, but that's just because where I get it from charges an obscene cut rate but full rolls are cheaper than shipping cut rate from the states (although the exchange rate now has changed that). I'd suggest you get into it with just one or two chapters (say 4&5) at first. Opinions vary as to the necessity of the training chapter (chapter three), I didn't do it, and I don't feel worse off for it. Nice thing about chapter 4 is you don't need your big table and everything for it, a smaller workspace will do. Once you're into it by a chapter or so, then you can make the call as to how fast you're going to get work done, and if you're doing the right thing and can finish, without being over your head in materials. Then, my advice is buy full rolls and etc for those things you need big batches of if you can store it properly (mostly this applies to glass, and if you're shipping, foam). Epoxy is *much* cheaper to pick up than ship, for some brands, including MGS 285/7 which I swear by. I pick mine up in Toronto, a five hour drive away from me. If you're picking up epoxy, may as well pick up as much foam as you have cargo space for (and, early on, need) as it's also one of the more expensive things to ship. Some people like Thayercraft for glass, and while I haven't used him before, the wider BID he sells seems like it would be good and it's price competative, and he seems to know enough to mention coating types etc when discussing the glass he sells. Just my two cents... My biggest piece of advice... Just buy the plans... treat them gently until you really start building (i.e. keep them pristine while you consider) and if you decide not to build you're likely to be able to get reasonable resale value from them (not so for materials/chapters built, which seem to barely recover cost of materials). Oh, and consider why you want to build, if you want to build because you like building AND flying, great, but if your interest is predominantly one and not the other, you're unlikely to finish in a timely manner (which is fine but perhaps lacking closure if you just like building, and which isn't a good way to get a plane if you just want to fly). Context: chapter 7 builder, about one year in.