Jim Sower

My only experience with parking brakes was on a Grumman I used to have 15 or 20 years ago. I've never been able to figure out what it's utility might be on an EZ or Cozy airplane. Like why would I need one. What do I miss out on if I don't have one? Could someone enlighten me ? .... Jim S.

I first ran into Greg about ten years ago in response to a couple of articles he wrote in Kitplanes about his first notions on EFIS. I've talked to him from time to time since and at OSH and Sun-Fun. He is the best I've met at what he does. He has the confidence in himself and his stuff to readily admit problems and fix them. VERY refreshing after what we've all become accustomed to. I'd buy ANY damn thing he built. I'm just that impressed with him. Jim S.

John, I just don't like the idea of a pump dedicated to a tank. It just feels creepy. The devistating failure mode of the original (all return to right tank) was kind of easy to spot. Thing is, I can't see any ADVANTAGE to dedicating a pump to a tank over having parallel pumps feeding the fuel rail. What do dedicated pumps buy you that you can't get from parallel pumps? OTOH, what do/can they cost you in the area of more serious failure modes? With dedicated pumps, you lose the fuel in the tank served by the failed pump. How will a pump fail? If it tends to fail while it is running, you end up with a lot more options than if a pump doesn't turn on when you switch to it. Timing of a failure and the options (or lack of) it leaves you can be real important. With Tracy's method, you have (pretty good?) (better?) options no matter when the failure occurs. I am very aware that I am really mind-f**king this thing. I'm just trying to make possible failures as benign as I can. I'm out of new answers. How does Tracy's method substantially increase plumbing? How do dedicated pumps decrease plumbing and/or complexity? Wish I had a nice tidy package for you .... Jim

<... Maybe I'll retrofit one later ...> It'll be much simpler that way. You'll know *exactly* how to do it. Jim

Hey all, Who's been following the thread on the rotary forum about Electric Water Pumps? At first it sounded like somebody's brain fart that needed a LOT of work just to find out if it's possible, much less practical. Then I found out that Leon has been working with this thing for a while and it's absolutely real. Seems it will draw under 10 amps and that by itself is a major recommendation for me. Lots of other other things lend themselves to our applications: no belt, remote mounting, recover power wasted by belt driven units, weight savings, etc. and best of all, a whole new cutting edge TOY!! I'm looking for some more details, but it sounds great. Jim S.

Two props for O-235 Long-EZ (or Vari-EZ). One is a G-A 62x64 with a largish dink that has been refurbished by Clark Lydick at Performance (who approves it as a good spare). The other is a Performance 62x62 also refurbished by Lydick. 6" extension and [vanilla] spinner. Props and extension are SAE-1 (4-3/8"). Main Prop $400, spare $200, extension $200. Catskill, NY

Seemed to me that most of the fixes the guy put in were more about his ides on how something should be put together structurally than a response to an actual problem. He did a lot of "beefing up" for reasons best known to himself. This does not imply that cross wired cables, etc. are acceptable. His implication that there are many more of these cables out there is based on - what? Strikes me that this guy has legitimate issues, but he's also trying to score some points. Mixing all the real stuff up with speculation and personal opinion only serves to muddy the waters. Just a theory .... Jim S.

John, Another consideration that makes your "Right = Main; Left = Reserve" design even more bulletproof is a "vent check valve" that they use in Velocities - it's a check valve that is closed when there is zero or positive pressure (like you're on the ground or flying with ram air) in the vent system. It opens to cabin pressure if the relative pressure (vent line pressure <=> cabin pressure goes negative. You have ram air vent to your strakes when the vent lines are open. You have cabin air to the strakes if a "dirt dauber" takes up residence in your vent(s). YOU'RE HOME FREE!!! If you installed a screen over the blister, theres NO WAY any trash can get into your fuel system that would block a 3/8" (or much less a 1/2") fuel line. Anything that could get through the screen will pass through the pump and get caught in the filter. Parallel fuel pumps. You could have one filter upstream from the pump and the other downstream if you want. Mount filters vertically so they can't accumulate moisture. Facet pump transfers from bottom of Reserve tank into the return line just before it enters the top of the Main tank. Facet pump lights a light when it's running so you're MUCH less likely to over fill the Main and vent fuel overboard. When the Reserve runs dry, the Facet pumps air bubbles into the return fuel until you notice that the Reserve is empty and turn it off (like, so what?). Fuel management task amounts to turning on the Facet pump from time to time to [nearly] top off the Main. If it fails, you've lost what's left in the reserve. When the transfer pump does fail, it's loss becomes obvious when you still have a nearly full Main tank. You've lost only the untransferred fuel in the Reserve tank. Return (hot?) fuel goes to the Main tank where it has maximum opportunity to cool, not to a small sump where it gets recirculated almost immediately. We've solved blocked vents above. Even if you don't use the check valves, a blocked Main vent will still "suck" fuel from the vented Reserve tank through the Facet pump. A blocked Reserve vent will seriously reduce transfer but perhaps not prevent it altogether; you can transfer until the Facet won't suck hard enough to overcome the vacuum in the Reserve tank. When you turn off the Facet, air will tend to leak (through fuel cap, vent restriction, etc.) and reduce the vacuum. Then you can use the Facet a little more. In any event, any blockage will be obvious in plenty of time to divert somewhere and fix it. NO vent blockage can go undetected long enough to cause a problem. The (my) problem with sump tanks is based on my own experience with my Velocity not transferring evenly (and sometimes not transferring at all from one strake). The Velocity fleet is rife with assymetric transfer problems, some worse than others. It's either a significant design defect in the Velocity or an inherent problem with sumps. But even if the strakes transferred perfectly to the sump, you'd still have the possibility of recirculating fuel before it had time to cool sufficiently. If I were you, I'd lose the gascolators. You can't avoid a low spot in the fuel line somewhere between the Main tank and the fuel pumps. Install a drain there if you must I see no particular value in it. Parking on your nose will put all the water over the strake drains. If you forget to drain your strakes on preflight, the water will, when you raise the nose, run straight to the blister, straight to the engine. You can't possibly get from your parking place to the runway on the fuel in the lines and the filter. Main tank water will ALWAYS reach the engine almost immediately after start. If you set up the lines to the injectors so that secondaries come out of the bottom of the rail and primarys out the top, you can't accumulate water in the rail, and a reasonable slug of water might not fill the whole rail so you might only lose half your injectors. Worst case is that for some reason, you drain the water from the Main but not the Reserve so that water from the Reserve goes to the engine sometime enroute when you begin transfer. This problem (draining the Main tank but not the Reserve) is worse than not transferring from the Reserve at all, or not noticing problems with the Facet. It cam ONLY happen if you're IFR (there is "no visual reference to the horizon" when you've got your head up your ass )). I think you're on the home stretch. Very low parts count (fewer failure modes), minimal plumbing and wiring (minimal failure modes), simple, economical and very easy to evolve from should you feel the need. Think I'll do mine that way too .... Jim S.

John, Couple of questions on the latest iteration of your design: < left tank will be the "sump". Return will always be to this tank > I would use the right tank as the sump. It is the easiest to check visually (using Vance's sight gauges). It will usually have more fuel in it (tending to balance you laterally when flying alone. < I will run a pump and filter from each tank to the rail > This one scares me a little. Suppose you've run off the left tank (pump) for a while and drawn the left fuel down to about half full. Now you switch to the right tank (pump) and start drawing it down, returning to the left tank. At cruise, we might assume for the sake of argument that you're returning about half the fuel pumped. You fly along filling up the left tank. About the time the right tank gets close to empty, the left one is close to full. You switch back to the left pump and the engine quits. The pump has failed. All you can do is switch back to the right pump, but it's dedicated to an empty tank. You only have just a few gallons left, and half of that is being pumped into an inaccessable tank. You're screwed. If you were at 8000' right OVER a suitable airfield, you'd still run out of gas before you could get down since at idle you're still pumping 30gph, and it's nearly ALL going to the dead tank. If you parallel the pumps from the right tank and return to the right tank, one or the other will be drawing from that tank. You periodically Facet fuel from the left tank to keep the right tank topped off. If the Facet fails, you have a nearly full tank and two pumps to draw from it. The only common failure mode is the Facet transfer pump. You'd be left without whatever was left in the left (backup/donor) tank. Pump failure would be pretty much a non-event. The only "unmanageable" failure mode is trash in the outlet line from the right (supply/return) tank. If you have screened off the entire blister, you'd need about half a bushel of trash to stop up the screen to where the engine wouldn't run. I don't think you've left that much stuff behind in your strakes. Anything that could get through the screen will happily flow through the plumbing to the filter (have one pump downstream from its filter, the other upstream if you want to to cover all the bases here ~ I prefer filters upstream to protect the pump as well as the injectors). Please think long and hard about pumping out of both tanks and returning to one. Best, Jim

Norm, <... everytime I mention it I get flamed with the complexity argument ... an engine that returns a significant fuel ... must allow for deaereation ... temperature dissipation ... valving ... tank selection criteria... Propose any solution, and it will be attacked with arguments of complexity and non-reliability ..> Yup. I agree entirely so far ... <... interesting and entertaining, but seem to be of minimal value for advancing the art of the design ... intelligent feedback from a forum group is like asking ...> Afraid we part company here. To the extent that John is pretty much plowing new ground, I feel he needs to consider all the angles. He thinks of as many as he can. The rest of us come up with our ideas. Nobody can quantify squat. The most informed decision John can make is to dig up every factor he can (with a little help from his friends) and evaluate them as best he can (lots of gut feeling here, not so much hard, reliable data). When he gets flying with whatever system he decides on, he reports results. The next guy, who does things a little differently, reports his results. Pretty soon we all have a much better idea as to what does and does not work. That, IMO, is how you "advance the art". Tracy does have a working system. I submit that his is not the only system that works, even if it is the only one that works NOW. We can improve on Tracy's system only to the extent that we dapart from it (but depart advisedly, since it is, after all, the one that works). <... and carve it open and do some motor stall tests ...> I think it would be really interesting and valuable to take the tour of the plant you took 10 yrs ago and get the answers to the questions I asked (and probably a bunch more). I have no doubt the engineers could quantify a LOT of stuff and either put my fears to rest, or tell me what I could expect along those lines. That would provide a lot of the "hard data" that is so tough to come by when you're "advancing the art". John has to evaluate all of the many (and occasionally not too well thought out) ideas and considerations. I think it is important that he be exposed to as close as he can get to ALL of them, and I don't think anyone knows for sure what ALL looks like. When he thinks he has what he needs, I recon he'll quietly retire from the thread and go to work... Just a theory .... Jim S.

John, <.. continuous duty, normally open solenoids to switch the returns ..> Goes to simplicity. Continuous duty might be more apt to fail, but the failure mode seems fairly benign. What about a pump failure? If your pumps are wired to the valve terminals could a valve failure precipitate a pump failure? What are all those failure modes? The solenoid valves "fail open" by design. Actually, they are "Y" type L-R valves with one outlet plugged (so you might only need one). We don't have any idea as to failure modes that might be *outside* of the design. <... I didnt say there's no room for a useable sump ...> My definition of "usable" implied a half hour or so of usable fuel. Looking back, that was tied to avoiding some of the consequences of my own ongoing problem of not knowing whether a tank was transferring modestly or not at all. Guess I was trying to "lower the height of the limb I was crawling out on". In any event, it is a bogus condition. Your 3 gal or so should be adequate. Particularly if you can put it somewhere that is relatively impractical for anything else. One thing I would NOT want in a sump is a flat bottom. Make the bottom slope a little toward the center and put a drain point there. Mine is flat, and if the plane is not sitting exactly dead level (which is rarely the case) the drain point is not at the low point and I will almost always have some water in the tank. Also, my fuel line to the pump is 2" off the bottom of the sump which I think is entirely too far. 1/2" to 3/4" should be enough. The inlet(s) go an inch into the tank so there's that much of a "bubble" in the sump. Flush with the top would be nice. <... fuel starvation is the number 2 cause of accidents ...> And I've suggested that fuel *management* is the number 2 cause of fuel starvation. How would you manage your fuel with a solenoid valve failure? Keep switching pumps all the time (and, of course, never get to that last 2 or 3 gal that I'm so anal about)? Tracy's system has only two failure modes that result in reduced access to fuel: blocked inlet and Facet failure. Yours has blocked inlet and solenoid valve failure. Oversize gravity feed lines (bet you never dreamed you'd hear that from ME ;o) to the sump and plumb all return fuel to the sump (no moving parts) has only one: blocked inlet. Of course, we have to assign a weight to each item in order to arrive at a really rational decision. That's hard. I'd need some help from Al Wick to do that properly. Of course Al would measure the pressure drop between the tank and pump inlet and have the "Monitor Girl" warn him "... you're sucking fuel through some trash, big boy ... You might want to check your inlet screens ..." Bottom line: what do you really know about these solenoid valves and how do you react to surprises around them? Your "generic tapped plate" access to the strake tanks would be a really good start. Gives you lots of flexibility for relatively little effort. <... mounting the filter vertically ...> If it's not much extra trouble, I would feed the injectors off the bottom of the rail instead of the top. This way, you run EVERY drop of water straight away into the engine before he can muster enough friends to give you a problem Lots of interesting questions. Glad it's you doing the installation and me doing the abstract guesswork instead of the other way around;) Jim S.

Are you talking "Dynamic" as in engine-prop combination? If so, maybe next trip to Atlanta (from Albany NY) I'll go by way of Lewiston ))

Norm, I have some questions ... <... Use a motorized valve for the return side ...> What happens to the motor when when the valve sticks mid-travel? If the motor stops when the valve stops (as one would intuit), that would stop back(counter) EMF and increase the current through the motor very significantly (like maybe double or so?). Does it just sit there and smoke, or blow a C/B or fuse, or what? <... that has one lead from the motor connected to the left pump, the other to the right pump. When you power one of the pumps, the return moves to that tank ...> I am assuming that when the motorized valve arrives at a selected position, the valve somehow turns the motor off (so it doesn't sit there and cook like above) but I guess that would all be internal circuity in the valve (lots of failure modes?). In any event, I'm having trouble visualizing how the pumps would be wired to such a valve. Perhaps by "connected" you're implying "through some relays and diodes and etc"? I'm having trouble visualizing the circuit. Also, unless wired through relays (each one a failure mode) the pumps could be expected to draw an order of magnitude more current than the valve circuit required. Which level of current do you protect (fuse)? <... If you power both pumps, it stays put. ... > I'm REALLY confused by this one. Guess I'll have to see a circuit diagram or somethng. Either way, how do you go about getting that last couple of gallons out of one tank so that late in the flight ALL of your fuel is where you want it? John, George makes a compelling case for a sump. You've made a compelling case that there's no room in a Cozy hell hole for a usable sump. It looks like a stand-off (which typically leads to a major compromise or an awkward work-around). That sort of brings me back to Tracy's design. One could maybe move a step or so toward having it both ways. He uses his right wing tank for a sump, returns all excess fuel from the rail to to the "sump". But instead of gravity feeding the sump from the left tank, he uses a facet pump to transfer left to right. Pressure pumps are not dedicated to either wing tank. You alternate them any way you please. But that's all been said. As for gascolators, my EZ has one on the bottom of the firewall (marginally) accessable from the NACA duct. Any water from the blisters through the selector and associated plumbing would presumably gather there. I found a cc or two water in the strakes on a pretty regular basis but never in the gascolator. I get a lot in the Velocity too. Both live in a hangar. Don't know how George avoided water in the strakes unless he used mogas in an area with lots of alcohol added. Anyway, I theorized that the plane would have to stand upright for extended periods for water to get there, and that was impossible without LOTS of ballast. I gave up on the crawling around it took to look there unless it had stood upright and ballasted for a long period of maintenance or it had been a LONG time between flights. For your application, look at the volume of the fuel system (plumbing and a filter or two) from the blister to the rail make a guess as to how much ground operation would be required to consume that much fuel. Sounds like it would run through the engine long before you could taxi to the runway. Just be sure and mount your fuel filters vertical (if they're horizontal, a good bit of water could accumuate in them that even a gascolator couldn't detect). Every answer seems to raise more questions ... Jim

Hey folks, I'm re-posting this from another forum. Seems like it might be something an EAA chapter would be interested in for the chapter tool chest (could be a revenue producer too). Wayne Owens wants a dynamic prop balancer. In order for me to get it at a less than staggering price I'll have to purchase it from Norman Serrano's company Vibe-tech. He can get them built for a price of less than $900 if a total of 30 of us agree to purchase one before Oct. 7. The company assembling the boards charges a lot for smaller orders. The price each for a quantity less than 30 made most folks gag. Norm called me today and said I need to round up 12 more orders to get over the hump. He has commitments for the other 18. He has some serious interest from Cirrus and a Gyrocopter company. Norm isn't much of a salesman ,nor am I. We are both engineers but I can see a good deal and a prop balancer for less than a grand is a good deal. He is looking for someone who will rep the product at S-n-F next spring or in other countries . He has a Rep in Germany and is looking for one in Australia. He also told me today of a plan to allow access to a Vibetec website with data from one of his machines so you could enter your data and get the full benefit of one of his $32,000 balancers. This should eliminate hand calculating and polar chart requirements. Please give him a call on his toll free number and ask him about the details. I want a balancer. Norm Serrano: 877 842 3835 Thanks Wayne Owens Eaa Chapter 268, Tech Counselor, Velocity builder 770 333 1578 Home 770 361 6379 Cell Ps.. please pass this on to anyone in the Chapter 690 --or anyone else who might be interested in purchasing one for chapter or individual use.

John, You're right of course. There's just not room in a Cozy hell hole for a practical sump ("practical" being defined as an emergency tank, or one that holds enough fuel that you can actually travel somewhere on the sump fuel). Your three gallons or less is, as a practical matter more space than you can afford to dedicate to a sump in a Cozy. A small sump like that would be usable in that you'd have a place to dump return fuel without lots of plumbing but that's the extent of it and it would scarcely be worth the bother. What I'm really talking about is something I'd like to see in a sump, but almost certainly won't. I can't make a compelling argument for a sump with significant fuel since the EZ and Cozy don't have anything like that and seem to work OK. But it does seem like a nice thing to have. You're on the right track withoug it .... Jim S.

Submerged pumps are certainly to be preferred (if you have easy, LEAKPROOF access). It does make for a bigger sump tho. If I was going to have a sump, I would want as much (5 or 6) usable fuel as possible. That way, when the low-sump light comes on, I can actually USE that information and GET somewhere. A 5-6 gal sump will pretty well cube out the hell hole of a Cozy and not leave much room for A LOT of stuff that has to reside there. If I have to give up on a sump with a useful fuel volume, I would have to have photocell low fuel transducers in the strakes so I would have a REAL reliable indication of 5 gal or so remaining. Not a big challenge, but something to pull my fat out of the fire when I forget to monitor my fuel, and an indication of assymetric transfer to the sump Good luck fishin' ... Jim S.

<... It seems that the complication of this system grows.... Agreed. I am in favor of a sump. John is not. My last post was oriented toward fuel management for his no-sump system. He does have a few points. One is that with a sump contamination of one strake contaminates the system. I personally think it's not a compelling argument since you're supposed to check for water in BOTH strakes, and if you don't check you're not likely to have dramatically more water in one than in the other. I would lean toward the strakes feeding a "T" through manual maintenance valves. The 'stem' of the 'T' would contain the fuel flow transducer. Fuel would be drawn from the sump, through an emergency shut-off valve, branch into one or the other pump/filter unit and thence to the fuel rail and returned (perhaps through a rudimentary cooler) to the sump. No moving parts other than FF transducer, emergency shutoff and pumps. Damn few failure modes. No fuel lines in the cabin. But it DOES have a sump .... Jim S.

John, <... If you INSIST on having access to every drop of fuel...> It's not ME that insists. It's my sister-in-law PRUDENCE. You've probably got one too. She's kind of obnoxious most of the time, but typically ends up with a compelling argument. Particularly AFTER THE FACT :>)) I have links to JC Whitney electrical L-R screw driven pumps (fail where they fail) that might work for you as well as a solenoid operated unit that can be plumbed to fail L or R. Since your solenoid will fail without warning at irregular (but arguably long) intervals, fail-Left into the tank you can purge would seem prudent here. Your return selector fails into my original design. Go with the solenoid (cheap) return selector valve, and clean up with the Facet pump (buy another you cheap screw, you can pay for it with the money you save on solenoid v. screw valve). The link for two of the JCW valves is: http://www.tvbf.org/gallery/?dir=subsystems%2FElectric_Fuel%20Valves jcwhitney.com has all manner of stuff. Tomorrow we'll look into it deeper :>)) Jim S.

John, <... I think the fuel would tend to flow to the tank currently being drawn. Once a tank is full I doubt the return will force fuel out of the vent rather than simply flow to the other tank...> ...think...doubt... are key words here. The numbers are very VERY small re pressures, etc. so a very minor restriction in one line would cause surprisingly dominant return to the other tank. In your favor is the notion that the vent line being smaller and pressurized by ram air would tend to prevent fuel loss over the side. OTOH, once fuel began dumping overboard, you would have a siphon effect of about twice the ram air pressure wanting to continue syphoning fuel. Your idea of "T"d return dumping half of a LOT of fuel into the unselected tank on descent late in the flight is an IMPORTANT consideration. I would suggest that we're now back in the "...all the fuel on board in the selected tank..." business with a vengance. One solution that suggests itself is to install a facet transfer from left tank to right. Just make a practice of ending your flight with the engine drawing from the right tank and the facet pump ON. a) Minor additional plumbing b) "T"d return OK c) Always end the flight with all your fuel in selected tank d) Facet pump overcomes assymetric return through "t" Only failure mode is if Right tank pump fails. If that happens, you know IMMEDIATELY (engine goes quiet) and as soon as you switch to the other pump (about 1.2 sec) you're heading most direct route to the nearest suitable air patch. If right pump fails very late in flight when left tank is empty, yo're screwed, but then again, if you want guarantees, buy a toaster. I'd say "T" the lines, install facet pump. Best, Jim S.

Hobbling today, playing basketball tomorrow. I'll take it. Been crippled for the past 4 or 5 years and that's my limit. Wish I'd done it a couple of years ago (but the technology hadn't reached Albany by then). See you in Port Gibson soon and we'll do some sprinting ..... Jim

<... My friend the accident investigator/7000 hour pilot overules all else in concerns to safty...> No argument here. I am an ex Marine Aviator with a commercial SE, ME, Inst rating 4000 hrs in tactical jets, over 1000 in combat. I majored in Aero Engineering in school. I did NOT fall off the turnip truck last week. I know about accidents. I have personally crashed and burned (blew the canopy, leapfrogged over the windscreen, slid down the nose and sprinted out of the fireball). I have spent afternoons out in the boondocks with a plastic bag and a butter knife scraping friends of mine off the trees and rocks. I am no stranger to the causes of accidents. I am walking around today because I learned from other folks' mistakes and misfortunes. Also a LOT of pure dumb luck. <... One mfg had vapor lock at 9500 feet because bubbles came out of fuel at that altitude and blocked the return lines, thats why they went to larger diameter fuel lines...> I have to believe that there was a little more to it than that, but that's OK. On a pressurized system, with the fuel supply at or above the pump inlet, and no serious preheating of the fuel, there will be no bubbles and bigger fuel lines serve no purpose. Do you really delude yourself that bigger fuel lines that solved some problem some where will automatically benefit you in your configuration and situation? <...isn't the fuel pump near the engine? > NO. It's on the other (cool) side of the firewall. <... if that is the case, then you just need...> You don't "just" need anything (with the possible exception of a "better-than-nodding" acquaintence with Mr. Newton). Fuel system, or any other system design is more than picking solutions that sound appealing and install them in the hope that perhaps they're relevant to your issues. <... the larger lines do that and the larger returns insure that any bubles won't ...> Larger than WHAT?? John's lines are large enough. They will work just fine. They have on any number of other applications. There is no reason in the world ("reason" is a key word here) to rush around "fixing" sh*t that ain't "broke". Harvey's Scond law: " ... if it works, dont f*** with it..." Harvey's First law: "... if you don't know what it does, don't f*** with it..." <...I know i am kicking a dead horse...> What are you talking about? What does a dead horse look like? Sound like? Do you find it useful to kick one? I've been open to discuss any idea that comes along that seems to impact the issues at hand in some relevant way. There are positives and negatives for every proposal. Some are relevant and some are not. We have to evaluate and weigh them, each within the context or our own application and come up with the best rational solution that we can. There is no compelling or convincing reason whativer to assume that the solution to someone else's problem (who we don't even know) will even be relevant to, much less slove, your problem (or John's or mine). <... but, few people have seen what my friend has seen ...> I have seen a enough of it to suit me. How much of it have YOU seen? How involved have you been in coming up with a solution for the problem that caused an accident? Your friend certainly has been more often than I. I certainly have been more often than you. <...The one mfg lost a number of planes before they found out that the returns needed to be bigger and piped to the top of the tank...> This the same mfgr as above, or a different one? <...I know i seem to simplify it...> You got THAT right! <...one valve at my fingertips...> What airplane are you building? Only the stick and throttle are at my fingertips. On my Long-EZ, and the fuel selector is "within reach" - where it can easily be (and occasionally is) overlooked. <...large lines to and from...> You seem fixated on big fuel lines like they are going to fix your life or something. If that was even _remotely_ true, EVERYONE would have big old fat fuel lines and life would be terriffic and everyone would live forever. I sincerely hope that big(er) fuel lines will actually be relevant to your design and somehow make it better. In addition, I truely hope you NEVER forget to switch tanks, that you somehow never run into a situation that leaves you short of fuel, that you ALWAYS have sunny days and tail winds and that you never ever run into a problem that can't be fixed by installing bigger fuel lines. Best regards, Jim Sower "...If your onliest solution is a hammer, the problems all start lookin' like a nail ..." My dear old Dad ...

John, Agreed. The bulk of the fuel starvation cases I would guess involved guys flying "instruments" (there's no 'visual reference to the horizon' when you've got your head up your ass ....). One of my times was exactly that - running my mouth and enjoying the flight and the scenery when .... The other involved a rather long IFR flight (with adequate but not excessive reserve) and most legs in excess of 100 nm. I was in the clag or between layers the whole hop. The winds were over twice the headwind forcast and when I called FSS 100 mi into the flight. I only had VORs, so accurate positioning and 'howgozit' was possible only at the widely separated waypoints. I knew by half way that I had unfavorable winds, by 70% or so that they were very unfavorabe and eating badly into my reserve. Figuring out positions to do fuel checks using crossing radials is unreliable on a _good_ day. This was a choppy *bad* day. I landed on fumes after running one tank pump empty while at altitude. It was a long way between air patches with approaches so I had little (but not *no*) choice as to where I would go. If I'd relied on my best guess of empty tank when I did my last switch, I would have run out scud running through a mountain pass 8 or 10 miles from my destination. One could, with 20-20 hindsight, come up with a number of alternative courses of action that would have got me on the ground with 5 gal of so. Gawd knows _I_ did. But I think I did a credible job under the circumstances. On account of that, I am really anal about having ALL of my fuel where I need it toward the end of _any_ flight. We are all moulded by our experiences .... Jim S. PS A tactical jet with 200 or 300 lbs of fuel is a real attention getter too.

Mike, <... too many pilots die from fuel starvation ...> Too many of them crash a mile or two from the airport with 'several' gallons of fuel in the UNselected tank. How does your system prevent this? I want, at the end of EVERY flight, to have ALL of the fuel on board in the tank that's feeding the engine. During recovery phase, I'm closest to the ground and the workload is highest. I don't want to have to worry then about fuel management and switching tanks. <... in the cockpit, well it is there, I only suggest doubling it ...> My system has NO high pressure (or low pressure for that matter) fuel lines in the cockpit. There are a few in the hell hole, none in the cabin area. I am not sure what bigger lines accomplishes other than making cramped spaces more cramped. Your system has roughly twice the plumbing in the cabin as mine has in the hell hole. Your valve is a failure point and constitutes pilot work load (and won't comfortably purge a tank). My transfer pump is a failure point that constitutes (I would argue somewhat less) pilot workload (and it always, very comfortably, purges a tank). <... you have made your mind up ...> Not yet. I'm a long way from plumbing my fuel system, and I won't 'make up my mind' until I'm right there. It's a judgement call. Lots of factors that we each weigh ourselves - I don't know how often you've had reason to run a tank 'pump empty', but I've done it several times and don't EVER want to have to do that again. Regards, Jim S.

I haven't seen much discussion of my own main objection to DD cooling which is the exhaust (and oil pan, etc.) preheating the cooling air. Maintenance access is clearly better, and baffling is much simplified. There are any number of ways to address oil cooling that don't involve the NACA duct. Bottom line: I'm impressed by what I see and I want to try it. But I'm repeating myself. I guess it's all been said .... Jim S.

Dale, I agree. That's why I said I might want to reshape the nose a little forward of the bulkheads - droop it down a little. Big as I am, I need lift from the fuselage too. Matter of fact, big as I am, I might even go back to the original canard span (and be very careful about aft CG operations).