If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Corvair conversion engines - cracked crank link
Morgans wrote: "Cal Vanize" wrote The article does indicate that the cranks were from engines in planes that were flying. That's the good news. But does that also mean that the engines need a teardown and inspection as part of every oil change? If you are running a conversion that is different from William's conversions, it could be a good idea. g If people take the time (yeah, lots of it) to read the whole article, you will notice a few things, and I will attempt to point out some of the more significant (to me) points. Biggest point. Do not use corvair engines outside of the recommended operating parameters. Some sub points. Biggest one, don't use longer prop extensions. Big time no-no. Others include, don't use heavy props, or hand carved props. Don't overstress the prop with some aerobatic maneuvers, or hard landings. Make sure the crank is properly ground. Oil systems must provide for consistent oil flow to all parts, at all times; stay away from two line cooler and filter systems. Use low RPMs and big props, rather than smaller props and higher RPMs. Avoid detonation, which is easy to let happen, if treated like an aircraft engine. Obey all points of his conversion manual. Nitrated cranks are a good way to add an extra margin of safety, when obeying the conversion manual, but the other examples that have followed the manual have been OK for long operational periods, even without the nitrated cranks. Avoid other's add ons, like extra bearing hubs, as they have not been tested. I am sure I missed some points, or miss stated some, but if you are using corvair power, it would be wise to investigate what this man has to say, and not take my word on it. I remember saying a long time ago, that I would feel better (or something like that) if a redrive was used to take the stress off of the crank. I think I will still stand by those words. Of course, It would need to be a properly researched and tested redrive, which at this time, does not exist. Good points all. The point that stood out most for me was the part about the crank from the engine that William built for his own demo 601. From the article: "This engine represents a standard installation, albeit one that was flown at its limits by Gus"... "showed stress fractures on both sides of the area in question." at 200 hours. "no nitride" Note with particuclar interest the phrase "represents a standard installation" regardless of how his pilot flew the plane (it was HIS pilot after all). The statement goes on to say that the engine "was flown at its limits" not beyond its limits. What William wrote is that an engine he purposefully built himself for his own 601 demo plane had a not insignificant crank issue. If he was following his own recommendations, why did he use a crank that wasn't treated? He may be the Corvair conversion expert, but I'd like to read an explanation as to why he wasn't following his own specs. I have read every word on William's web site. It would appear that he has done his homework and research. He may be the most credible source for Corvair conversion aircraft engines. But yet, this discrepency sticks out sorely. |
#12
|
|||
|
|||
Corvair conversion engines - cracked crank link
"Cal Vanize" wrote Good points all. The point that stood out most for me was the part about the crank from the engine that William built for his own demo 601. From the article: "This engine represents a standard installation, albeit one that was flown at its limits by Gus"... "showed stress fractures on both sides of the area in question." at 200 hours. "no nitride" \ Yes, that paragraph does seem to run contrary to the rest of the _long_ website's information. So what gives, others in the know? -- Jim in NC |
#13
|
|||
|
|||
Corvair conversion engines - cracked crank link
Morgans wrote:
"Cal Vanize" wrote Good points all. \ Yes, that paragraph does seem to run contrary to the rest of the _long_ website's information. So what gives, others in the know? Or could it be that it's just taken a few years to rack up 200 hours? I didn't catch a time span reference on any of the example engines. But I thought it has been years? |
#14
|
|||
|
|||
Corvair conversion engines - cracked crank link
Richard Lamb wrote: Morgans wrote: "Cal Vanize" wrote Good points all. \ Yes, that paragraph does seem to run contrary to the rest of the _long_ website's information. So what gives, others in the know? Or could it be that it's just taken a few years to rack up 200 hours? I didn't catch a time span reference on any of the example engines. But I thought it has been years? First flight of William's 601 was 13 May 2004. That engine had 200 hours. The article implies that all the engines were torn down at about the same time. It must have been fairly recently because one of the engines was a 2005 engine with 71 hours. The previous "crank update" was 15 August. |
#15
|
|||
|
|||
Corvair conversion engines
But would you have to replace the engine?
Maybe just a crank overhaul every 4-500 hours, in the middle of winter, after a good snow storm, nothing else to do. |
#16
|
|||
|
|||
Corvair conversion engines
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? |
#17
|
|||
|
|||
Corvair conversion engines
"Lou" wrote in message oups.com... But would you have to replace the engine? Maybe just a crank overhaul every 4-500 hours, in the middle of winter, after a good snow storm, nothing else to do. Good point what would a like new, best for the engine, crankshaft cost? |
#18
|
|||
|
|||
Corvair conversion engines
$50-76 on ebay,
$600 to have Bill Wynne modify it. |
#19
|
|||
|
|||
Corvair conversion engines
"Lou" wrote in message ups.com... $50-76 on ebay, $600 to have Bill Wynne modify it. Replace it every year or two at annual it's still a great deal. |
#20
|
|||
|
|||
Corvair conversion engines - cracked crank link
Morgans wrote:
"Cal Vanize" wrote Good points all. The point that stood out most for me was the part about the crank from the engine that William built for his own demo 601. From the article: "This engine represents a standard installation, albeit one that was flown at its limits by Gus"... "showed stress fractures on both sides of the area in question." at 200 hours. "no nitride" \ Yes, that paragraph does seem to run contrary to the rest of the _long_ website's information. So what gives, others in the know? My read was that he was updating his policy based on new data. He even mentioned one of his customers reminding him of a sentence in his conversion manual saying something like "I reserve the right to get smarter." |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Book Review: Converting Auto Engines for Experimental Aircraft , Finch | Paul | Home Built | 0 | October 18th 04 10:14 PM |
P-3C Ditches with Four Engines Out, All Survive! | Scet | Military Aviation | 6 | September 27th 04 01:09 AM |
What if the germans... | Charles Gray | Military Aviation | 119 | January 26th 04 11:20 PM |
Corvair Engine Conversion Breakin Success | Dick | Home Built | 1 | January 11th 04 02:06 PM |
Corvair Conversion | Gig Giacona | Home Built | 17 | October 27th 03 09:43 PM |