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There are 3 series of 20B engines IIRC. The center housing and the crank on some of the earlier versions was reported to be a weak link……..later versions had mods to some internal parts. I have a later version of the 20B. You can tell from the rotor housing engine numbers (where the 20B is in black surround). Marc From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Friday, February 06, 2015 4:17 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: 20B Engines Thanks Mark........That is the info I was looking for............I happen to have a 13B Cosmo that has the later housings and I had only read about the reinforced housings......... On Fri, Feb 6, 2015 at 6:49 AM, Mark Steitle <flyrotary@lancaironline.net> wrote: I wouldn't hesitate to use an early 20b. The early 20b housings are plenty robust enough for a/c use. The beefier irons could be an issue if you're building a turbo race engine due to the higher loads imposed during up shifting and down shifting. We don't experience any of those loads. I'm pretty certain that my 20b is an early model and I have not experienced any issues with irons cracking around the dowels. The weakest area is along the inner walls of the o-ring grooves nearest the water jackets. If your o-rings aren't to factory specs, you run the risk of cracking an o-ring wall which ruins the housing. Been there, done that. If you treat the engine with the same care you would a certified a/c engine, then you won't have any trouble with longevity. Mark On Fri, Feb 6, 2015 at 12:00 AM, Kelly Troyer <flyrotary@lancaironline.net> wrote: Mark Steitle or other 20B Drivers, I am looking at a 20B that looks to be an early one before they added additional metal in the dowel/oil passage area of the iron housings because of some that I have read developed cracks in this area in service in the autos I presume....... Can you tell me if this a potential problem for the 20B in our aircraft use ?.......Also can you tell me if your 20B has the later reinforced housings ?.........
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