VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Avionics / Interiors / Fiberglass > Engine Monitors
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 07-02-2015, 12:55 PM
Mike H Mike H is offline
 
Join Date: May 2014
Location: Savannah
Posts: 806
Default

Just another myth that gets perpetuated and beat to death.
__________________
Mike Hammond
A&P IA PPL ASEL
RV-14A kit S/N 140170
Reply With Quote
  #12  
Old 07-03-2015, 06:54 AM
David-aviator David-aviator is offline
 
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
Default

Quote:
Originally Posted by Mike H View Post
Just another myth that gets perpetuated and beat to death.
I agree, don't think it is a big deal unless pulling 60" MP (as I recall) with a P&W 4360.

It had 2 gear driven superchargers and one turbocharger. Cool down rate was very important as the engines only ran about 600 hours at best.

Also true with some Lycomings and Continentals but I don't think anyone is super or turbo charging an RV, yet.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
Reply With Quote
  #13  
Old 07-03-2015, 07:06 AM
chazking's Avatar
chazking chazking is offline
 
Join Date: Jul 2006
Location: State of Bliss
Posts: 396
Default Non Issue

Caution with the cooling rate, but no need to agonize over it. Myth put to rest.
__________________
Ch?z King
Reply With Quote
  #14  
Old 07-03-2015, 07:32 AM
kenora kenora is offline
 
Join Date: Sep 2007
Location: Winnipeg, Manitoba, Canada
Posts: 40
Default

This is just a FWIW post...

I have been towing gliders with a variety of Scouts (O360) for decades... we climb at 65 mph and regularly see 400 - 430 f cylinder head temps in the summer.
After release we throttle back to 2100 RPM (top of caution zone) and descend at 100 - 110 mph till we see 300 f cyl head temps (after a climb to 4000 agl or more it can be several minutes) but we are targeting 100 f/minute.
as soon as the cyl head temps drop below 300 f its power OFF and maintain 100-110 mph to short final... regularly see 1000 - 1500 fpm descent.
We have NEVER cracked a cylinder using this rather aggressive cooling technique and repeat the cycle 6 times an hour for 8-10 hours a day x July and August.
my 2 cents...... they RARELY break and we regularly get to TBO
Reply With Quote
  #15  
Old 07-04-2015, 03:35 AM
dutchroll dutchroll is offline
 
Join Date: Jun 2010
Location: Sydney, Australia
Posts: 123
Default

On my radial (the M14P) the only "cooling" limitation is the bottom end of the CHT range which is 120 deg C.

The Russians specifically mention not allowing it to go below this temp during power off descent, but there is no "shock cooling" limit at all providing it is kept above the minimum operating temperature. Also they require CHT to stabilise < 150 deg C prior to engine shutdown, which makes perfect sense. Given that the engine has been around for several decades, I imagine they would know by now if shock cooling was an issue.

I agree there seems to be more paranoia about this than is really necessary (arguably fed by some of the engine monitor manufacturers).
__________________
Mike
Down Under

Last edited by dutchroll : 07-04-2015 at 03:38 AM.
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 07:33 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.