Go Back  RCU Forums > Glow Engines, Gas Engines, Fuel & Mfg Support Forums > Glow Engines
Reload this Page >

Question on outside air temp effect on glow engine peak RPM

Notices
Glow Engines Discuss RC glow engines

Question on outside air temp effect on glow engine peak RPM

Old 01-15-2021, 04:52 AM
  #1  
ahdofu
Thread Starter
 
Join Date: Jul 2003
Location: Bellevue, WA
Posts: 36
Received 0 Likes on 0 Posts
Default Question on outside air temp effect on glow engine peak RPM

Do you see a change in the peak RPM of a glow engine in cold vs. warm days? In summer time this particular engine of mine was peaking at 9400 RPM (OAT ~ 75 degs). Yesterday it reached 8900 RPM at OAT of 50 degs. On one hand the higher density of air affects the power needs of the prop but then the higher air density should also help the motor as well. Anyway I was wondering what folks have experienced. BTW this is an OS Surpass 91P glow engine using a MA 14x6 prop with Omega 18/15 fuel.
Old 01-15-2021, 10:58 AM
  #2  
Jesse Open
 
Jesse Open's Avatar
 
Join Date: Mar 2018
Location: 30 Miles North of Canada Border
Posts: 3,736
Received 91 Likes on 83 Posts
Default

Nearing 45 degrees, methanol vaporization is becoming difficult.
Old 01-16-2021, 04:51 AM
  #3  
ahdofu
Thread Starter
 
Join Date: Jul 2003
Location: Bellevue, WA
Posts: 36
Received 0 Likes on 0 Posts
Default

Thanks for the reply back. I'll try again when the weather gets a bit better.
Old 01-16-2021, 06:27 PM
  #4  
the Wasp
My Feedback: (1)
 
Join Date: Sep 2003
Location: VT
Posts: 5,378
Likes: 0
Received 41 Likes on 39 Posts
Default

Originally Posted by ahdofu
Do you see a change in the peak RPM of a glow engine in cold vs. warm days? In summer time this particular engine of mine was peaking at 9400 RPM (OAT ~ 75 degs). Yesterday it reached 8900 RPM at OAT of 50 degs. On one hand the higher density of air affects the power needs of the prop but then the higher air density should also help the motor as well. Anyway I was wondering what folks have experienced. BTW this is an OS Surpass 91P glow engine using a MA 14x6 prop with Omega 18/15 fuel.
yes !
the colder the air is the richer you need to tune

Jim
Old 01-16-2021, 07:07 PM
  #5  
Jesse Open
 
Jesse Open's Avatar
 
Join Date: Mar 2018
Location: 30 Miles North of Canada Border
Posts: 3,736
Received 91 Likes on 83 Posts
Default

Originally Posted by ahdofu
Thanks for the reply back. I'll try again when the weather gets a bit better.

With a low temp, methanol fuel won't start by itself. We used to preheat the engines and give a shot of ciggy lighter fluid down the carb. They would run but fussy and fuel draw became weak.
Power was down indeed.
Old 01-16-2021, 09:25 PM
  #6  
tedsander
 
Join Date: Jul 2004
Location: White Bear lake, MN
Posts: 754
Likes: 0
Received 68 Likes on 64 Posts
Default

It gets REALLY interesting on days when it is -5F or -10F. But no issues with overheating, or having humidity factor into the power equation.....

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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.