Wildguzzi.com

General Category => General Discussion => Topic started by: Gliderjohn on December 16, 2021, 04:39:33 PM

Title: Question about shock cooling of air cooled engines.
Post by: Gliderjohn on December 16, 2021, 04:39:33 PM

In the aviation world one is taught to be aware of "shock cooling" of air cooled piston aircraft engines and how to prevent it but never here of it with air cooled motorcycle engines. Why/what is the difference?
GliderJohn

Title: Re: Question about shock cooling of air cooled engines.
Post by: Guzzistajohn on December 16, 2021, 05:10:07 PM

Ridden BULTACO'S through many a swollen stream. They always went deep and came up dry and running  :grin: And I've pulled the plug, turned them up-side-down to pump out water too  :thumb:

Title: Re: Question about shock cooling of air cooled engines.
Post by: lucky phil on December 16, 2021, 05:23:17 PM

A myth.

https://www.avweb.com/ownership/shock-cooling-time-to-kill-the-myth/

Ciao

Title: Re: Question about shock cooling of air cooled engines.
Post by: Gliderjohn on December 16, 2021, 08:46:41 PM

Thanks for the link lucky phil. Interesting read. Our club tow pilots generally do a fairly quick decent.
GliderJohn

Title: Re: Question about shock cooling of air cooled engines.
Post by: lucky phil on December 16, 2021, 09:24:45 PM

There's is an amazing amount of stuff to learn about big aircraft radial engine operation and I read quite a lot about it from a pilot that had been flying them for many years and wrote about the intricacies and debunked a lot of old myths. One was to never let any people inexperienced at hand turning the prop of a big radial engine through it's "blades" prior to starting as if they are unaccustomed to the "feel" of a cylinder hydraulic locking they can walk it right through the lock and bend a rod. Better to rely on the starter clutch to protect the engine and "bump" it through that way. Quite amazing, I never thought it was an issue. I spent hours and hours reading his stuff. No longer with us unfortunately, another - victim.

Ciao   

Title: Re: Question about shock cooling of air cooled engines.
Post by: 9fingers on December 17, 2021, 07:23:54 AM

Quote from: Guzzistajohn on December 16, 2021, 05:10:07 PM

Ridden BULTACO'S through many a swollen stream. They always went deep and came up dry and running  :grin: And I've pulled the plug, turned them up-side-down to pump out water too  :thumb:

Sherpa T?, Alpina, Matador?
Scott

Title: Re: Question about shock cooling of air cooled engines.
Post by: Chuck in Indiana on December 17, 2021, 11:17:24 AM

Quote from: 9fingers on December 17, 2021, 07:23:54 AM

Sherpa T?, Alpina, Matador?
Scott

I've pumped water out of a matador the same way.  :smiley:

Title: Re: Question about shock cooling of air cooled engines.
Post by: Guzzistajohn on December 17, 2021, 11:24:27 AM

Quote from: 9fingers on December 17, 2021, 07:23:54 AM

Sherpa T?, Alpina, Matador?
Scott

SHERPA, still have a 72 and a 76

Title: Re: Question about shock cooling of air cooled engines.
Post by: SmithSwede on December 17, 2021, 06:39:18 PM

Good question John and great article Phil.  I had read about this for years, and it always struck me a “used male cow food.”  Sounds like my hunch was correct. 

But I will confess that I would wonder or worry about this whenever I’d been bombing down the highway for hours at 85 mph on a stinking hot engine and then suddenly hit pouring rain.  Gee, is the engine maybe really unhappy about that abrupt transition?

Title: Re: Question about shock cooling of air cooled engines.
Post by: mtiberio on December 18, 2021, 10:04:24 AM

I remember seizing a two stroke roadracer at the end of the straight because I chopped a throttle. Cut off the lube oil source for the skirts.