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![]() clare wrote: On Fri, 20 Jan 2006 08:06:33 -0600, Cal Vanize wrote: I don't think there's any dispute over the relative cost of engines. This issue is longevity and whether one wants to fly an airplane with an engine that might not make it to the next airport. You mean like a Lycoming? or an old Franklin? Can't speak for Franklins. But I've never had even a skip on Lycomings with with over 400 hours flying PIC in plances with Lyc engines nor with any Conti with over 500 hours PIC in those. These weren't in homebuilts. |
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clare at snyder.on.ca wrote:
On Fri, 20 Jan 2006 08:06:33 -0600, Cal Vanize wrote: I don't think there's any dispute over the relative cost of engines. This issue is longevity and whether one wants to fly an airplane with an engine that might not make it to the next airport. You mean like a Lycoming? or an old Franklin? Oh for Pete Sake...ok. A couple of years back, I picked up an Aeronca Chief down in Florida and flew it home. Real nice airplane, and a real bargain - because - the engine wasn't all that great. Continental 85 with metal prop. It had been "overhauled" by one of the club members (not A.P.) and they (the sellers) were honest about it up front. It leaked (a bit). And they were right reasonable on the price. So a deal was offered, $1000 earnest money sent. And Leo and I went down to see?/fetch? We flew it around for a while and determined that the plane was rigged nice and straight, stalled straight ahead, and with the 85 and a climb prop, it could for sure and certain - climb! The little engine ran strong. Checking the oil level shortly after landing (yeah, I know) showed it had indeed lost some oil, but we found it - all on the belly. Oh well, I'm not going to have to clean it. Not part of the deal. The seller offered to "wipe her down and top off the oil and gas". (yeah, I know - now.) So, next morning, oil and gas are full and we headed off for home. It took 3 days to get home and about 12 hours flying. Two hour legs left an hour fuel reserve for the Chief. And the climb prop doesn't go anywhere in a hurry - except up. This engine leaked so much oil it would embarrassed a Harley. I mean really! But something else was wrong. The engine ran fine, but it felt a little sharper than normal during climbs, but smooth out fine at cruise. For the next three days (over swamps, timber, and once VFR on top, I could actually hear/feel/taste it getting worse. A little sharper at first. Then louder. Each takeoff. Only while climbing. On the last leg home I thought maybe an exhaust muff was opening up maybe? And then thought - or a cracked mount? But it smoothed out at cruise. When we rolled out at home, I was glad to be there, because I had decided that the engine was indeed failing and needed to be looked over. Very carefully. BEFORE flying it again. It still ran strong, but something was really major league wrong somewhere during climb out. When Bob (A.P.) tore it down he found the bad seals, sure, and some other minor stuff, and one cylinder with a crack about 1/4 of the circumference of the flange. The crank and cam were ok. Mags ok. A (as in one each - count it) new jug, bearings, seals, etc. signed off major overhaul cost 4 grand. Grandpa, the new owner, it totally tickled with his Chief. He learned to fly in it. Took his PPSEL check ride in it. Took his _wife_ flying in it! Someday his boys will have their chance to learn to fly in it. So, what exactly is the point, you ask? This issue is longevity and whether one wants to fly an airplane with an engine that might not make it to the next airport. Right Hell if I know. But it was a fun trip otherwise... Richard |
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I bought two 3.8L Ford V6's for $150 each, bought new pistons from Roush racing, new rings, had the best block shot peened bored and honed, had the best crank turned and nitrided, bought new bearings, new cam, new distributer with two sensors installed for dual ignition, new pistons, new timing gears and chain, planed the heads, had four new intake valves installed and new guides installed as well, new valve springs, roller rockers, new lifters, new carburetor, old style NWAero psru, ARP studs for the crank bearings and cylinderheads, fabricated my own headers, and STILL spent only about $6,000. Why not fuel injected? Also, is that two for $3K each? What does that setup weigh? Was matching a prop to your engine a problem? 3 bladed prop? Curious... Montblack |
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On Fri, 20 Jan 2006 13:17:48 -0600, "Montblack"
wrote: wrote) I bought two 3.8L Ford V6's for $150 each, bought new pistons from Roush racing, new rings, had the best block shot peened bored and honed, had the best crank turned and nitrided, bought new bearings, new cam, new distributer with two sensors installed for dual ignition, new pistons, new timing gears and chain, planed the heads, had four new intake valves installed and new guides installed as well, new valve springs, roller rockers, new lifters, new carburetor, old style NWAero psru, ARP studs for the crank bearings and cylinderheads, fabricated my own headers, and STILL spent only about $6,000. Why not fuel injected? Also, is that two for $3K each? What does that setup weigh? Was matching a prop to your engine a problem? 3 bladed prop? Curious... Montblack I didn't go fuel injected for two reasons, simplicity and safety. Carburetors don't need an electrical system to operate and are basically pretty simple. If you are a mechanic, carburators are easy to diagnose and repair. Fuel injection requires a relatively high pressure fuel pump and of course, the injectors. Both of which are likely electrically operated. The carburetor *may* use a fuel pump, but it's of the 5 - 7 psi variety, and with a high wing airplane, isn't absolutely necessary in order to get fuel to the carburetor. So if the fuel pump fails, you likely will still be running. Plus, my entire premise was to not reinvent the wheel. Using the auto fuel injection requires the use of the car's computer. Using the computer requires all the sensors and sometimes faking the sensors out so that they give the proper information. It all seemed too arcane and difficult for me. Carburation does not produce less power than fuel injection, but it might be slightly less efficient, depending on how the engine is leaned, and how much the pilot pays attention to it. I paid $150 for each engine, and built one engine, not two. The weight of the setup is one of those "not sure's". It likely weighed in excess of 400 lbs, but probably not by much. The block is cast steel, but it's a thinwall design. The heads are aluminum, as is the timing chain cover, and intake manifold. It was the lightest V-6 being built, and may still be in it's 4.2L form. I also used the lightweight geared starter, rather than the routine Ford beast. The NWAero psru is noted for it's relative light weight compared to the Blanton version, which was it's genesis. I also used a lightweight aluminum machined flywheel, rather than the suggested Ford flexplate. Probably no gain or loss there. As to the prop, I bought an IVO Magnum and ran it using that while I tested the engine. I added largish mufflers to the header system I fabricated (header length and diameter suggested by "Headers by Ed". Ed sizes header tubes scientifically to promote maximum flow at the power settings most often used and altitude at which I would normally be flying. That required relatively small diameter header pipes (1 3/8), which is considerably smaller than the exhaust ports in the heads (1 3/4). The length of the headers tubes was also specified to maximise torque, which meant that they had to be 40" long and feed into 3" diameter collector pipes, which had to be at least two feet long each. When I first fired the engine up, all animals in the vicinity headed for the hills. It seemed like I was standing next to two machine guns blasting away. Of course, I was inside the shop at the time (with the sliding door open). I had to add two hefty mufflers to the exhaust system in order to run it outside the house without being attacked by the neighbors, even though I live in rural Vermont, with lots of trees between me and my neighbors. They were big and unwieldy and I wasn't planning to use them in the airplane. But I was unhappy with how noisy the engine was and was concerned about being a good citizen when flying in the area. I tried several inserts to try to quiet the barking down some, but nothing but actual mufflers helped. With the mufflers, you basically only heard the soft clicking of the lifters and the hiss of the carburator, over the whopping of the prop. As I advanced the throttle, the carburetor began moaning/roaring and the noise of that big prop took over with a whapping blatting roar. I literally had to chain the test stand/engine down securely or it would have tipped over for sure. I had built a test stand that was basically a fully instrumented vehical on casters. It had a battery, radiator and fuel tank. I could have strapped it into a flatbed pontoon boat and gone air boating. I had the engine up to around 3,500 or so for the last run before I shut it down and sold it and the airplane. At that rpm, lots of air was being blown back and things like rakes and shovels were flying off the walls of the car port. The test stand was tied down to the car port posts, which is why the air was blowing into the bays. It was obvious I would have needed to back off on the prop pitch a bit to get more rpm out of the engine, if I had continued. Corky Scott |
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[good report snipped] I didn't go fuel injected for two reasons, simplicity and safety. Thank you for the report. Montblack |
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#7
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I just think hanging a prop on a crank directly is a non-starter in
the first place...especially on a crank and case not specifically designed for this in the first palce. Maybe a good redrive and flywheel would be a better way to go? That is my opinion, also. -- I partially agree. I agree that hanging a prop directly on the end of an automotive crank, even if you put it on the flywheel end, is a recipe for a short tbo even at low power and for a high failure rate at high power. (If you only use it to push an airboat around the local swamp, you can keep a couple of bottles of skin-so-soft in your tackle box.) However, switching to a traditional aircraft powerplant may not solve the problem. You really only have the full value of testing, experience, and service history when you mate an unmodified engine to an airworthy propeller with which that engine was certified--and preferrably in a combination used by a large number of aircraft in regular service for a reasonably long time. Remember the crankshaft problems in some of the Cessna 172's soon after the change from the Continental O-300 to the Lycoming O-320. (I think it was an early 160HP version, but have long forgotter the dash number--and the problem was promptly solved.) There have been other "teething" problems as well on various engines... In the special case of a KR-2, which was the subject of at lease two of the Corvair engines torn down and inspected, the plane sits too low to swing a 70+ inch diameter propeller; and IIRC was originally designed for VW engines swnging 52 inch diameter propellers. I have heard that the KR-2S sits enough higher to accept a larger prop, possibly 60 inch diameter. That seems to negate the reduction drives, although a shaft drive, similar to the one Steve Whittman developed for his V8 powered Tailwind, could be interesting. BTW, the plans are still available--I think Aircraft Spruce still sells them. Also, Revmaster (and possibly others) offers an aircraft engine based loosly on the VW dimensions and a Jabiru could work--especially with a 3 blade prop... |
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On Thu, 19 Jan 2006 15:35:13 -0500, "Morgans"
wrote: "Bret Ludwig" wrote in message roups.com... I just think hanging a prop on a crank directly is a non-starter in the first place...especially on a crank and case not specifically designed for this in the first palce. Maybe a good redrive and flywheel would be a better way to go? That is my opinion, also. What isn't there can't break. That's my reson for a direct drive 'vair insted of a geared Soob - same weight - same HP. |
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![]() clare at snyder.on.ca wrote in message ... What isn't there can't break. That's my reson for a direct drive 'vair insted of a geared Soob - same weight - same HP. Perhaps you missed the news flash, from the Corvair Authority, himself. The 'vair cranks are breaking on the new glass planes. -- Jim in NC |
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On Tue, 24 Jan 2006 22:19:55 -0500, "Morgans"
wrote: clare at snyder.on.ca wrote in message .. . What isn't there can't break. That's my reson for a direct drive 'vair insted of a geared Soob - same weight - same HP. Perhaps you missed the news flash, from the Corvair Authority, himself. The 'vair cranks are breaking on the new glass planes. Yup, I'm aware. but the reduction box has more parts to fail. There have been Rinker failures, and not much else in use. Lots of PSRU failures on Soobs. Mine's not fast, and not glass, and my crank is nitrided from the factory. |
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