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#1
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what every boy needs - yeah seriously
veedubber and others
the venerable old VW engine conversion is quite usable. if you were to take all the lessons learnt from all the engine building done so far and apply them to a new engine design, what would the new engine design look like? I think the flat 4 makes a very serviceable aircraft engine. underslung pushrods like the O-200 and VW would remain. I'd use hydraulic lifters. the castings for the crankcase would be simpler, more like the O-200 than the complexities of the VW casing. the crankshaft would be a little more robust at the front end I'd fin the pushrod tubes and use the oil returning to the crankcase as a radiator. the engine would be mounted on dynafocal lord mounts. I'd use electron for the crankcasings. spin on oil filter. (z79) magnet in the sumpplug. what else??? Stealth Pilot |
#2
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what every boy needs - yeah seriously
"Stealth Pilot" schrieb im Newsbeitrag ... veedubber and others the venerable old VW engine conversion is quite usable. if you were to take all the lessons learnt from all the engine building done so far and apply them to a new engine design, what would the new engine design look like? would look like this one: http://www.ulpower.com/ |
#3
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what every boy needs - yeah seriously
All of that is out there, already available. But the truth is, it's
not needed; not in the immediate sense. What IS needed are aluminum head-castings having twice as much fin- area as what's presently available. This won't fit on a bug or bus so there is no start-up money. Coming up with the cores should have been done by the EAA -- about fifty years ago. The fact it wasn't is good evidence that it won't. The need for juice lifters is appreciated -- and they are already available, if you start with a late-model Mexican crankcase (it uses the Type IV hydraulic lifters). But you can reduce your valve adjustments to once every fifty hours or so by tossing the stock adjuster screw and replacing them with the swivel-foot type. Flat-to- flat, the valve adjustment wears at a glacial rate, assuming the valve- train geometry has been set up properly, which it isn't in nine engines out of ten. But the VW simply lacks the Good Stuff that is found in a REAL aircraft engine, such as 8x the bearing area, and a flanged crankshaft carried in a massive Final Bearing similar in size to that on the A65. Modern ignition systems are actually superior to the typical backwards Slick, and there is no evidence supporting a need for dual ignition, other than the Feel Good legislation passed in 1937 imposed upon us after some Legislator's son augered in the E2 of the college flying club. College. Rich kid(s). Our tax money to teach them to fly. Until a Representative from Illinois wanted to know what the hell was going on? Why only those particular colleges? And nothing for female college students nor, heaven forbid, BLACK college students.(*) So everyone jumped in and hung their favorite line-item onto the legislation and THAT's how we ended up with a mandate to provide TWO ignition systems rather than one. But most folks aren't bright enough to figure it out. These are the same technical idiots who think adulterating gasoline with subsidized alcohol fer crysakes is a GOOD idea when it's roughly akin to shooting yourself in the foot while practicing your Fast Draw in front of the mirror. So we end up with the only organization that claims to speak for the grass-roots aviators doesn't, and the only government agency that claims to speak for aviation in general, won't. Because it is so highly politicized that we're as likely to be ordered to put a flashing red light on the nose of our airplanes during the Christmas season, as to have them do anything that truly fosters 'General' aviation... so long as the General happens to be driving a jet or turbo-prop. The point of all that is that it really doesn't have a lot to do with powerplants. Nor even with airplanes. What it has to do with is Money and Politics and the desperate urge to fix things that aren't broke. Want some examples of this & that? Tear down an aircraft engine, compare it's rod bearing area to that of the Volkswagen. Indeed, tear down a MODEL T and do the same! To sling a prop, hour after hour and year after year, we need something we ain't got. But leave it up to the 'experts' and we'll be forced to fly behind a 1300cc power-head running six grand into a PSRU that costs about that and has a TBO that doesn't match the power head. In fact, if our lives are going to depend upon a gear-box from Lapland we might as well push for a ceramic turbine as the hot-section... and use the same basic engine for everything from 50hp to 200hp. But we won't. We'll be stuck with whatever us we'ens can throw together because when push comes to shove, there aren't enough of us to even influence the plowing under of some of our most cherished air fields. And while a certain well-funded few will assemble their RV's and do everything By the Book, a significantly larger number of dyed in the wool American's will notice that there aren't any traffic cops in the sky and that, as much as various agencies wish otherwise, there's nothing than your personal integrity to prevent you from building yourself a flying machine and using it as such, tens of hours each month and hundreds of hours each year, without any numbers of any kind -- without those LUXURY taxes the bean-counters insist on charging you. But of course, that will divorce you from the SOCIAL aspects of General Aviation and that right there will be enough to protect all those Americans who fear having something fall upon their heads unless it is first blessed by some bureaucracy. THEN it's okay for it to fall down upon their heads. --------------------------------------------------------- It's not just the engine, although if we're talking about powered flight it doesn't take a Rocket Scientist to see that the engine(s) has a lot to do with it. Nor is it about the Politicians, although anyone bright enough to pour **** out of a boot realizes we have the best government money can buy. And it's not about the bureaucrats either, since they are largely concerned with events AFTER they happen. Which leaves the only group that has anything to do with the issue, which is guys like you & me. In my case the fact I live well below the 'official' poverty line renders me invisible. Which means I can build and fly as much as I want to, without having any effect at all upon the Important Decisions which shape the future of American aviation (and Australian too, when you get down to it). -R.S.Hoover |
#4
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what every boy needs - yeah seriously
what else??? Stealth Pilot As VeeDubber has pointed out the heads are the limiting factor for HP. The VW has other problems but workarounds for them have been found, even if they are inelegant ones. I've looked at and sawed up more VW heads, and sketched out more ways to improve them, than a sane person would be willing to admit to in public. If one insists on dual plugs and a true improvement (other than just more cooling capacity) then I haven't been able to come up with a solution - unless one also moves the camshaft and spaces the lobes out to match the bore spacing. This requires a new crankcase as well. Doing this opens up MANY options using inexpensive off the shelf parts. I'm thinking a split head, like Scat makes, but following the layout of a Porsche 356 might be a good starting point? Oil-cooled VW heads are an option I have not heard anyone talk about for aircraft use. I've not done any math related to this option but it seems to be a viable one. Anyone actually tried the methods used by Porsche tuners on a VW? ======================== Leon McAtee |
#5
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what every boy needs - yeah seriously
On Jan 8, 12:37*pm, Stealth Pilot
wrote: veedubber and others the venerable old VW engine conversion is quite usable. if you were to take all the lessons learnt from all the engine building done so far and apply them to a new engine design, what would the new engine design look like? A Subaru? |
#6
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what every boy needs - yeah seriously
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#7
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what every boy needs - yeah seriously
Monk wrote:
On Jan 8, 12:37 pm, Stealth Pilot wrote: veedubber and others the venerable old VW engine conversion is quite usable. if you were to take all the lessons learnt from all the engine building done so far and apply them to a new engine design, what would the new engine design look like? A Subaru? We had one running direct drive - at 40 to 50 hp. But to use the full potential it needs a proper PSRU - along with all the extra weight that implies. (Ever try to prop a motor with a PSRU on it?_ |
#9
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what every boy needs - yeah seriously
Stealth Pilot wrote:
veedubber and others the venerable old VW engine conversion is quite usable. if you were to take all the lessons learnt from all the engine building done so far and apply them to a new engine design, what would the new engine design look like? I think the flat 4 makes a very serviceable aircraft engine. underslung pushrods like the O-200 and VW would remain. I'd use hydraulic lifters. the castings for the crankcase would be simpler, more like the O-200 than the complexities of the VW casing. the crankshaft would be a little more robust at the front end I'd fin the pushrod tubes and use the oil returning to the crankcase as a radiator. the engine would be mounted on dynafocal lord mounts. I'd use electron for the crankcasings. spin on oil filter. (z79) magnet in the sumpplug. what else??? Stealth Pilot Would you please expand on "electron for crankcasings" |
#10
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what every boy needs - yeah seriously
On Jan 8, 3:56*pm, Monk wrote:
A Subaru? --------------------------------------------------------------------------------------------------- Not bad. But it's going to come down to the Bottom Line. And in that regard, the individual heads are the winners. Why? Because we can do the machining ourselves. First off, we can forget about lost-foam or anything more exotic than green-sand, simply because there aren't enough of us. So we stick to standard, readily available valves, valve guides, valve seats and studs. The fins make the castings pretty tricky but if it was easy you would have seen it years ago. There's a couple of directions we can't go but if we borrow a page from the Corvair we can position our exhaust stack just about anywhere and still have a good seal. Most of us have MIG, which means we can do the stack-extensions. And since it's a new casting we can provide the boss for the hold-down bolt. Here again, borrow a page from the Corvair (or from GM) and we end up with a 'rocker arm' that actually works. The tricky bit is that it does NOT need to be aligned on a shaft... we can literally put a valve anywhere there is room. And that means at any angle as well. Domed or hemi-shaped chamber won't buy us anything. I'm pretty sure of that, based on some work I did in that area about 30 years ago. But that's actually to our advantage. By keeping the combustion chamber simple we keep our valve-train geometry simple. AND YES, we run juicers. Exhaust outlet to the stack is probably a rectangle, as with the Porsche. We put the wiggles into the exhaust stacks, which we make out of Monel or whatever, secured with that bolt we stole from the Corvair. So we make a L-head and an R-head; mirror images. We do the best we can with the fins but recognize our limitations and leave the most difficult of them as CUT fins: Rather than try to cast perfect fins in a couple of high-risk areas, we settle for a quarter-inch bar of aluminum that's configured for easy SAWING, which we do as part of the flash clean-up. -R.S.Hoover |
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