Jim Sower

If Joe had just said ... was said elsewhere (by whoever) ... "...his text/snip..."There would have been no disturbance at all. <... Are you suggesting we should ask dust if we can say "enjoy the build" ...> This and the rest of your list of "should I's" is a silly and deliberate extrapolation that seems to be designed to keep the fires burning <... Accreditation (which is a new topic, and has nothing to do with what we are talking about, thanks Jim) is most likely appropriate, and common courtesy, but may not be in all circumstances...> Guess I must be on the wrong thread. I thought accreditation was central to Marc's response that started this whole silly pissing contest (which has already consumed far FAR more time and energy than it was ever worth). Agreed. And then the whole freakin' forum seems to have stampeded into that same morass. I think everything of merit (and a woeful amount of sh*t devoid of any merit at all) has already been said. GAWD!! I wish we could move on to something important. Perhaps we can all agree that nothing that anyone says from here on out is going change anyone's mind. Then could we move on?

RV advantages: Pre punched kit Should go together much quicker then a Cozy I haven't seen a lot of really compelling evidence of that. In any event, putting an airframe on the landing gear is about half the project, so you don't really save that much. And an RV requires lots more tools than a razor blade, scissors, paint brush and squeegee. <... which would be easier for a first time builder with NO experience ...> NOBODY has any experience going in. Most of the folks on this forum think composite is easier (Duuuuhh!) but that's a personal preference. Perhaps influenced by tool list? Just a theory ....

Try to make it lighter I would guess - and perhaps simpler ....

C'mon ladies .... let's settle down and think this thing through ... Marc has a point. Attribution and permission are common courtesy. Ask for permission and you will get it. Make a reasonable effort to ask and see to it that you attribute and you have done your courtesy and can get on with things. If Marc sounds a little intense (like he's acquiring my gift for assertive responses to smallish issues:)) it does not alter the fact that he's dead right. I can't see where saying "please" and "thank you" is an unreasonable burden on any of us, or an impediment to the free flow of information. Mentioning sources is pretty much the rule here anyway - when No4 jumps in my sh*t, he doesn't act like he invented all those formulas - he names the book he read them out of - so that I can read up on my stuff. What's all the excitement about? Joe slipped. He (or any of the rest of us) probably won't again. How is any of this worth getting all pissy and worked up over? Once again it's P.V.O.R.T time.

That's freakin' preposterous!! I've got $1mil liability and not-in-motion hull on Velocity and n-i-m on my EZ for about $2k. Someting's really REALLY wrong here. Have you talked to Falcon? They seem to be the best for canards. Everyone on the Velocity list swears by them, and V is arguably the most uninsurable airplane around. I can get you an agent name and number .... Jim

Yeah. I understand that detonation is a major drawback to water injection, and it's hard to control tight enough to get good benefit without putting yourself in jeorpady of detonation. In a rotary, there's no pistons to burn holes in, but there are apex seals, and breaking one disables two "cylinders". So John shouldn't worry too much about spray bars and pumps and metering. He barely has tanks enough for the fuel that beast is going to consume. No place to put a water tank. But talk about great density! 7.5 lb/cuft. I think they used water injection on F-105 (it needed all the help it could get). They HAD to use it on TO if they had it. Otherwise they were toting 300# or water around with them, and it was a block of ice in a ruptured tank by the time they got home.

I have only heard vague references to Mach stall (unless there is another label that I might be more familiar with) and you have piqued my curiosity. How about some details how exactly it works .... <... Once Mach stall occurs, the nose drops, the speed builds, the Mach stall gets worse ...> I would have guessed that the transonic drag rise would inhibit acceleration. But then again, if the nose drops uncontrolably, acceleration is no longer necessary ... you don't need to be more uncontrollable - just maintain the speed/uncontrollability you've got. In any event, I'm trying to visualize how a nacient shock wave at the peak of the canard airfoil would stall the canard as I don't recall experiencing that on the main wing of planes that I have flown (in my very limited experience) transonically. My recollection involves a little nose tuck and then recovery as you move on to supersonic. Does it have to do with the shock wave blanking and neutralizing the elevator? I'm out of guesses. Help me out please ....

Cozy is IMO the very best airplane you can build. ...up up and awaaaay! might turn a little bit on how far awaaaay you're talking about. It's a good way to go with me and my lady and (maybe) a couple of small kids. Don't know what you and yours weigh. You've got maybe 1000 lbs tops for payload, and a full bag of fuel is 300. 700 lbs split 4 ways (5 if you count luggage) and you might have to short load fuel. But don't worry - I can count on my fingers the times I've heard of anyone on a Cozy list or the Velocity list discuss cross countrys with 4 adults. It has a nice ring to it, but just doesn't occur in nature. It is most certainly doable, but stuff works a lot better with just the two of you. Four adults on a local (200 mi radius) sight seeing trip would work great. For extended vacations you'd have to be really good friends. That said, Cozy is still far and away the best deal you can get in a homebuilt, and a homebuilt is easily the best deal you can get in GA. Go for it !!!

Steve, I was, in my own inimitable way, going to respond to your questions around what kind of engine to use with a couple of thousand words of deathless prose on the subject. I am no fan of Lycoming for a variety of very good reasons. Anyway, there is a better way to go. To quote my friend and mentor John Slade: The playing field is changing. My advice is get on and build the airframe and give little thought to which engine will power it until the last possible minute. In 3, 4 or 5 years the situation will have changed. That much is certain. Perhaps rotary and/or subaru powerplants will have proven themselves. Perhaps not. There might be a reasonably priced diesel available (dont hold your breath). Perhaps insurance will be easier, or harder to get. Maybe the available fuels and/or prices will have changed. To anyone just getting started I say don't even think about it. Keep in touch with what's going on, but save you're decision until you're airframe is complete..... then examine the issues as they stand at that time with respect to performance history, cost, insurability etc. etc. I belong to the Cozy email list, this forum, the Rotary list and (until I settled on Mazda) the Subaru list. If you follow the Cozy list and this forum, you will get tons of information on engines while you're building your airframe. Take it all in, but don't take any of it too seriously. Again, quoting Dr. Slade: Four or five years from now, you will make a very well informed decision around which engine you are going to install in your Cozy. That decision will be rational and astute and based at least 80% on information that won't exist for another two or three years. To quote another respected contributor: Enjoy the build! Getting worked up about engines at this stage of the game is an exercise in mental masturbation. If you really really feel you need all that prose, let me know and I'll work someting up and send it offline. These guys have heard most of it and a lot of it is in the archives anyway. Best, Jim S.

<... many of the issues with juries is they do not make awards based on facts, but based on emotions and sympathy ...> I think more important is the makeup of the jury. In this country, anyone who can read and write and count to twelve OR has a steady job, can find a way to beg off of jury duty. That leaves lonely housewives and the chronically unemployed in the jury pool. Jury duty is a lot like parenthood in that they are both critically important to the nation, and yet have NO prerequisites. You cannot be ignorant or stupid enough to be disqualified from these endeavors. It's scary as hell considering how much we all have riding on these activities.

In my haste I missed mplafleur's idea of a heat exchanger in the oil pan. That's a great idea. Answers all of my concerns: Oil heat (source), low pressure system. Recirculating oil (water occurred to me first, but if a line breaks in the pan ....) through several feet of tubing snaking through the bottom of the oil pan would be the perfectly benign heat source. Bring the lines out toward the top of the pan so a leak at the entrance/exit wouldn't be a serious problem, operate it with electric pump and blower and you're there. The worst (and arguably the least likely) thing that could happen would be a leak or failure where the plumbing enters/exits the pan, and you could put that high enough to be a fairly benign failure. You'd have to fasten the tubing to the pan pretty good to prevent fatigue, but that's certainly not rocket science. Might think of much lower viscosity oil for heat exchange and ease of pumping considerations. Great headwork!!

My Velocity has an oil cooler in the nose and tries to bleed/redirect exhaust from it to the cabin. It doesn't work well for a variety of reasons - mostly design defects. I'm with Wayne on this one - use a smaller capacity heat source and recirculate the air - except that I feel very strongly that it should be a low-pressure system. Oil lends itself nicely, but I don't like the idea of introducing high pressure oil and the attendant failure modes to the cabin heat system. An idea that just came to me: Since the oil pump bypasses most of the oil back to the pan at operating rpm, why not put a "T" in the oil line to/from your cooler, followed by a small (1/8" max) orifice that would feed oil into the 1/4" or greater ID plumbing to your cockpit heat exchanger - perhaps located in the hell hole, or perhaps in the nose - and thence back to the pan. Small heater core, recirculating air, low pressure system. The orifice into the heating system could be calibrated to provide juuuust enough oil to do the job and not bypass oil that was needed for lubrication.

I used to be really enthralled by lots of power. It was the key to Goooo-->Fast!!!. Then I learned how to do the math and was introduced to cost-benefit. It pretty disappointing. Like: You start with 180hp and 180 kts .... If you increase power by 50%, to 270 hp, you increase your speed by 1.5^1/3 or 1.14 and you end up with 206 kts. What does the extra 90 hp cost you (in things like Capitalization, Design Modifications, Development Effort, Maintenance and Operating Costs ... Ask around about engineering and development effort for severe mods that have been done. Examine capital price and maintenance costs (and, of course, fuel) of O-360 v. O-540; Mazda 13B v. 270 hp diesel; Soob EJ-25 v. 240 hp whatever (EJ-33?). What does it buy you by way of getting to a typical destination (4 hrs away)? You get there like 30 minutes earlier. There's bragging rights of course. What are the other benefits. Try to quantify them. I don't mean to piss in your corn flakes, but these are some of the things you have to examine honestly and open mindedly. You ignore them at your peril. I was hugely enthusiastic about super powered Cozys until I did the math.

I thought a regulator and canula(sp?) were a lot more affordable than that, and that you could get refils at any welding supply place for chump change. Guess I'll have to revisit my references ....

<... Is electrical heating pad out of the question? ...> Pretty much. Someone on another thread did the math a while back and it was a huge drain. Now, they do make electric drawers that don't use a lot of power, but they cost a king's ransom, and I don't know what to expect if there's a short or something. <... i might have to rely on fluid and fan, the book is open ...> What if you were to weld/braize a couple of nipples to the oil pan (at the level of maybe 3-4 qt above the bottom, find an electric motor that will pump hot oil and plumb it to a little heat exchanger in the cockpit (those little 2-tube highly finned hydraulic coolers that used to be fastened to power steering systems years ago come to mind). You could install it for chump change. It's low pressure (like 3 psi) so it won't leak, enters/leaves the pan above the 4-qt level in case it does leak, totally idle when not in use. If simplicity is a consideration ....

Lots of interesting chatter. Many posts produce more heat than light. Nearly all have some "current" value - contribute something to the immediate conversation - but many have little if any long term value. What if there was a button one could select while composing a message that would flag it for archive while the default would limit the life of that particular post to a couple of months? Might keep the archives managable - prevent them from being too cluttered up with banter. I think lots of people (notably me) would just as soon not always be speaking for the record - the current audience, the current conversation would suit me fine most of the time.

My very limited understanding of flutter is that: A) The math and structural analysis is hideous B) The condition is significantly altered by relatively small changes in structure. Since Cozys are only very marginally standard, small (and not so small) departures from "design" parameters like stiffness, etc. will abound. That being the case, even if one actually knew all the "design parameters" that affect flutter, and was able to do the math, I suspect that a proper analysis would still be extremely elusive. I believe that it is doubtful that a homebuilder could build two canards sufficiently alike for results to be accurately predictive of performance. I believe it would be very doubtful if a group of diverse homebuilders could build a group of canards to any acceptable standard at all as far as flutter analysis is concerned. Burt tested the elevators to about 200 kts. He is reasonably certain that within the construction parameters he has put forth, they will not flutter below maybe 220 kts. Beyond that, you are on your own. You could test to higher speeds and accept the anecdotal data as valid, but that's about it. That's my shot with what I know .... Now that said, I'm looking for something on the order of 1000 mile range. That's 5 hrs at 200 kts (if I am clever enough and lucky enough to get 200 kts cruise out of a NA rotary). That's also right at 10 gal/hr with hardly any reserve at all. I'd have to be really REALLY clever to get 10 gph at 200 kts. If you could cruise at over 250 kts, with your turbocharged whatever, you would certainly get less mpg than me, so you would get closer to 800 - 850 miles on the same load of fuel. Any destination between your range and mine, I'd get there before you. Any destination short of your range, you'd get there at most 40 min earlier. If that's worth all the extra trouble and expense, go for it. To me, another half hour doesn't matter that much. Particularly since I'm arriving as far ahead of the Lyc Cozys as you are arriving ahead of me. The more I do the math, the more attractive simple and inexpensive gets ... Jim S.

<... But if the elevators are made right is there a flutter issue ...> Above 220 mph (or whatever Nat has designated as Vne), Nat and many others would argue that nobody knows. Airspeed (both True and Indicated) is a very important factor in flutter. You'd have to analyze it or have it analyzed or do your own flight test and pray for rain ....

Thrust of a propeller IIRC is M(V2-V1) so, unlike an energy function that would vary exponentially with velocity, it doesn't much matter if you accelerate a little bit of air a lot or a lot of air a little bit so long as M * delta-V is the same. The flow into and out of a prop disc (that doesn't have a lot of structure around it) is kind of funnel shaped - it tapers from an area larger than the disc ahead of the disc to an area smaller than the disc aft of the prop. A look at the cross section of a duct tells us that it is replicating (and perhaps enhancing) this natural phenomenon. Props have tip losses and that, basically, is what ducted fans aim to address. Sadly, they don't eliminate them altogether and the solution tends to outweigh the problem. Perry is a very bright fellow who has done his homework really well. It is extremely unlikely that he would miss something as fundamental as critical flow around his fan blades. Ducted fans work well when lashed to a turbojet, but I tend to believe that if they provided any real improvement elsewhere, we would find them elsewhere, which we don't. Perry is far from plowing new ground here. He has discovered that he can reduce tip losses but not eliminate them by any means, and the inefficiencies of the fan itself cost him more than the increased tip efficiency buys him back. Furthermore, the duct is heavy and draggy and I doubt any of us will be able to produce a fan so much more efficient than a prop that it overcomes the intrinsic overhead of the duct. But then again, the object of the exercise is experimentation and education, so go for it!! Hope I can be forgiven if I don't hold my breath until the big breakthrough.

<... you may be sued anyway and defending a suit can be expensive ...> About how far into a suit is "discovery"? Like, if'n I get sued, how much money will I have to spend before the opposing lawyer finds out to his satisfaction that I don't have anything worth him taking it away from me? How far along in the process does he learn that I'm indigenous and that my only asset was my airplane which is no longer an asset? Just wonderin ... Jim S.

<...guys from Dayton did it about 100 years ago...> As I recall they had real problems with overcontrol. Didn't the recent "flights" of the replicas exhibit severe pitch sensitivity? What I forgot to mention earlier was "... why would you want to? My EZ elevators were flush or very slightly TE down when flat out (maybe 150-160 kts) and maybe 3/4" TE down on final approach. My Velocity lands with 3/4" TE down elevator with over 450# in the front seat, and cruises 150kts elevator flush with just me (260#) in the front seat. I've never seen more than 3/4" of elevator trim from cruise to landing on any canard I've flown. Marc - what is the most difference in deflection in cruise/landing that you've seen? Years ago I thought about it for a while as a way to get enough pitch authority to overcome / trim out the nose-down pitch from deploying flaps. Also thought about putting the canard on rails and sliding it forward when flaps were lowered. After thinking it through for a while, I decided that since I landed at 125 kts for most of the flying I ever did, why am I straining my brain to get from 70 down to 65 on my EZ/Cozy. It was nuts. Brain fart, pure and simple.

<...has anyone or any design used a solid rotating canard as the elevator...> Just off the top of my head I think of several potential problems: You would pretty much lose the "stall proof" feature of your canard airplane - one of its more important attributes. The reason the main wing doesn't stall is that the canard stalls first. The reason the canard stalls first is that the canard airfoil stalls at a lower AoA (for the most part) than the main wing, and locking them both at the same incidence is the source of your assurance that the canard will reach its stall AoA before the main wing. Unlock the canard incidence from main wing and you have no such assurances. You'd have the structural engineering problem from hell figuring out how to pivot the spar without resorting to a fairly massive structure. Making the canard pivot would require a flutter solution for the whole canard which, I would hazard a guess, would be rather more elaborate than just balancing elevarors by the hinge. Just a theory .... Jim S.

<...I used the plasma spray coating process on the inside of plasma guns with great success. Reduced heatloss in the plasma a lot. Therefore reduced cooling requirements. The coating that I used was more exotic than one would need for exhaust pipes...> What are plasma guns? How hot and how hard flow, etc.? <...ceramic coat the piston faces, valve faces, cylinder head ... US$100...special paint on the exhauslt manifold, turbine casing, tailpipe for another US$30... .coat the remaining moving parts ...vastly improves lubrication for US$70...Not bad improvements to an engine for $200...improved hp, reduced operating temps, improved turbocharger efficiency...> Let's see .... the last time a guy offered to fix my life for a hundred bucks .... Is the exhaust treatment on the inside or outside of the pipe? If it's outside, pipe has to absorb the heat that doesn't transfer, if it's inside, how does it hold up to the exhaust pulses and all the nasty stuff in exhaust? How many racing teams use this stuff and what do they have to say about it? In my experience, stuff that sounds too good to be true ....

Doc, Marc's figures as posted at 11:13 on 1/18 are, IMO. good as gold. To wit: These come from a stall speed of about 72 mph at that weight. Given that (at Sea Level), the Vn curve below Va for the COZY looks like: 0 degree bank - stall speed ~72 mph - 1 G 60 degree bank - stall speed ~96 mph - 2 G 70.5 degree bank - stall speed ~126 mph - 3 G 74.7 degree bank - stall speed ~142 mph - 3.8 G 80.4 degree bank - stall speed ~180 mph - 6 G Since the Va of the COZY is about 140 mph (IIRC), I've got to assume that Nat picked the 3.8 G from the normal category of certification to get his Va. If Va was 180 mph, then 6 G would be the limit. Anyway, given this info, increasing speed up to 140 mph will, as you said, give you the tightest turning radius - from ~125 m radius at 2 G to about 110 m at 140 mph and 3.8G. You can verify them all while you're flying off your hours. It's not a big deal. Pick a series of airspeeds (80, 90, 100, 110, 120, 130, 140, 150, etc), set yourself up at each one, start a steep turn and pull to buffet. If you can't maintain your speed in a level turn (a certainty above 100 mph or so), let the nose fall into a spiral so you can maintain buffet, G and airspeed long enough to get a good G reading (don't know where you might borrow a G-meter - that's up to you). After you obtain all your data points, plot a graph and that's your Vn diagram. Or take it on faith that over the past 4 or 5 pages of posts, Marc and I have flailed some usable truth out of one another. For my own part, I am going to convert Marc's airspeeds to knots, plot his numbers and be done with it (at least until my airplane is flying). As a practical matter, 140 mph (I will be using 120 kts) is the number to remember in that it is the speed to use in severe turbulence. The lower numbers are of interest just to instill in your mind that below about 130 mph you don't have squat for maneuverability (re the "box canyon" scenario). When scud running or flying up "valleys" that you haven't been in, ...keep your Mach up ...!! 180 mph (156 (use 155)) kts is the highest speed at which you cannot pull the wings off the airplane. It is also the speed for the absolute shortest radius turn you can do without damaging the airplane. The 180 figure ("corner" of the Vn diagram) is of no particular interest or utility in the Cozy community - beyond trivia questions and sea stories. Many years ago, in another life, it was a really really important thing for me to know. That was then, this is now .... Jim S.

Why can't I access it on Netscape 4.77 *OR* Explorer 6.0 ??? What am I missing? Is *anyone* able to paint all the images and make it work right??