Go Back  R/C Tech Forums > General Forums > Nitro On-Road
Advice About Ethanol in an RC Nitro Engine >

Advice About Ethanol in an RC Nitro Engine

Like Tree6Likes
  • 1 Post By MX304
  • 2 Post By Rick Vessell
  • 1 Post By 1/8 IC Fan
  • 1 Post By Bsthetech
  • 1 Post By rc_hydro

Advice About Ethanol in an RC Nitro Engine

Old 03-29-2022, 04:16 PM
  #1  
Tech Rookie
Thread Starter
 
Join Date: Mar 2022
Location: UK
Posts: 2
Smile Advice About Ethanol in an RC Nitro Engine

Hi there!

I'm a (total) beginner looking for some advice about using ethanol in a nitro engine, So a little background info:

There's a group project I'm doing where we test the efficiency of various methods of propulsion in RC cars. So my task is to look into using biofuels (in this case alcohols).
This of course includes methanol, but I'm quite interested in using ethanol. I intend on using a 2-stroke nitro RC engine, 0% nitro, 15-18% Klotz Benol castor oil and ethanol. However my biggest concern is whether or not theg glow plug can remain hot enough with ethanol. What do you guys think? Are there any other things that I should be concerned about??

If it helps:
- The engine won't be running at full throttle (or at least for very long)
- The engine will likely be running for a somewhat prolonged period of time (although if we design the experiment, the engine will only be running for a short period of time for each reading)
- There will be no long term use of the engine

Excuse my lack of knowledge and any responses are greatly appreciated

Thanks, P0tatoPatato
P0tatoPatato is offline  
Old 03-29-2022, 05:40 PM
  #2  
Tech Champion
iTrader: (8)
 
Join Date: Aug 2002
Location: Oxnard, CA
Posts: 6,249
Trader Rating: 8 (100%+)
Default

Originally Posted by P0tatoPatato View Post
Hi there!

I'm a (total) beginner looking for some advice about using ethanol in a nitro engine, So a little background info:

There's a group project I'm doing where we test the efficiency of various methods of propulsion in RC cars. So my task is to look into using biofuels (in this case alcohols).
This of course includes methanol, but I'm quite interested in using ethanol. I intend on using a 2-stroke nitro RC engine, 0% nitro, 15-18% Klotz Benol castor oil and ethanol. However my biggest concern is whether or not theg glow plug can remain hot enough with ethanol. What do you guys think? Are there any other things that I should be concerned about??

If it helps:
- The engine won't be running at full throttle (or at least for very long)
- The engine will likely be running for a somewhat prolonged period of time (although if we design the experiment, the engine will only be running for a short period of time for each reading)
- There will be no long term use of the engine

Excuse my lack of knowledge and any responses are greatly appreciated

Thanks, P0tatoPatato
You can always wire the glow plug to always have voltage on it, that way you're not relying on combustion to keep it hot.
nitrodude is offline  
Old 03-29-2022, 05:56 PM
  #3  
Tech Lord
iTrader: (24)
 
wingracer's Avatar
 
Join Date: Nov 2007
Posts: 13,615
Trader Rating: 24 (100%+)
Default

I have no experience with ethanol so can't give specifics but I can think of two problems you could run into

1. Getting the right compression ratio / head shimming. I have no idea where to even start with that.

2. Ethanol has a less pronounced cooling effect. This could lead to temp problems and vapor locking though if you are not running wide open, that might not be as much of an issue. Could also cause pre-ignition problems but that goes back to the first problem.
wingracer is offline  
Old 03-29-2022, 06:05 PM
  #4  
Tech Champion
iTrader: (102)
 
1/8 IC Fan's Avatar
 
Join Date: Jan 2012
Location: Holland, MI
Posts: 6,459
Trader Rating: 102 (100%+)
Default

Originally Posted by nitrodude View Post
You can always wire the glow plug to always have voltage on it, that way you're not relying on combustion to keep it hot.
wont that Pre-ignite the incomming mixture, and therefore not allow decent cycling?
1/8 IC Fan is offline  
Old 03-29-2022, 07:49 PM
  #5  
Tech Elite
iTrader: (21)
 
Join Date: Dec 2011
Location: Texas
Posts: 3,768
Trader Rating: 21 (100%+)
Default

Dig around on some of the RC aircraft forums and search for "FAI fuel", which is just 80% Methanol and 20% castor oil. You should be able to get a good idea of what it takes to make it work.
Rick Vessell likes this.
MX304 is offline  
Old 03-30-2022, 03:07 AM
  #6  
Tech Rookie
Thread Starter
 
Join Date: Mar 2022
Location: UK
Posts: 2
Default

Sounds like a good idea. Will do.
P0tatoPatato is offline  
Old 03-30-2022, 08:30 AM
  #7  
Tech Elite
iTrader: (10)
 
Rick Vessell's Avatar
 
Join Date: Jan 2002
Location: Central IL
Posts: 2,475
Trader Rating: 10 (100%+)
Default

Originally Posted by 1/8 IC Fan View Post
wont that Pre-ignite the incomming mixture, and therefore not allow decent cycling?
No, airplanes use glow plug heaters to keep the plug lit at low throttle to prevent stalling during landings.
nitrodude and 1/8 IC Fan like this.
Rick Vessell is offline  
Old 03-30-2022, 08:31 AM
  #8  
Tech Elite
iTrader: (10)
 
Rick Vessell's Avatar
 
Join Date: Jan 2002
Location: Central IL
Posts: 2,475
Trader Rating: 10 (100%+)
Default

Originally Posted by P0tatoPatato View Post
Sounds like a good idea. Will do.
Straight alcohol with no nitro content will have a hard time idling. Keep that in mind with your testing.
Rick Vessell is offline  
Old 03-30-2022, 08:48 AM
  #9  
Tech Lord
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 11,184
Default

From what I was told is that Ethanol has a higher burning energy than Methanol, With that knowledge it is clear you need to adapt the ignition timing (glow plug number and/or head clearance) to make it work. Once I did run an Ethanol based fuel w/o adapting the compression and the idle was unreliable. I do believe those high energy fuels like the Runnertime Ultra (16% but needs headclearance of 25%) are based on Ethanol.
Roelof is offline  
Old 03-30-2022, 10:27 AM
  #10  
Tech Addict
iTrader: (16)
 
Bsthetech's Avatar
 
Join Date: Oct 2019
Location: Earth
Posts: 628
Trader Rating: 16 (100%+)
Default

Better to ask on RCGroups. The airplane guys spend alot of time messing with different fuel combos.
Bsthetech is offline  
Old 03-30-2022, 01:14 PM
  #11  
Tech Champion
iTrader: (102)
 
1/8 IC Fan's Avatar
 
Join Date: Jan 2012
Location: Holland, MI
Posts: 6,459
Trader Rating: 102 (100%+)
Default

Originally Posted by Rick Vessell View Post
No, airplanes use glow plug heaters to keep the plug lit at low throttle to prevent stalling during landings.
Good to know, thanks Rick, learned something new.
Rick Vessell likes this.
1/8 IC Fan is offline  
Old 03-30-2022, 02:39 PM
  #12  
Tech Addict
iTrader: (16)
 
Bsthetech's Avatar
 
Join Date: Oct 2019
Location: Earth
Posts: 628
Trader Rating: 16 (100%+)
Default

Originally Posted by Rick Vessell View Post
No, airplanes use glow plug heaters to keep the plug lit at low throttle to prevent stalling during landings.
I'm actually in the process of switching a four-stroke glow motor over to ignition. All the power of nitromethane, with added fuel efficiency, less oil mess, and more reliability.
Rick Vessell likes this.
Bsthetech is offline  
Old 03-30-2022, 07:26 PM
  #13  
Tech Rookie
 
Join Date: Mar 2019
Posts: 17
Default

The engine will be a little harder to start on the no nitro mix and wont idle as nice as even a low nitro fuel like 5% without changes to the combustion chamber shape and a hot glow plug. You could always prime the engine prior to starting with a few drops on nitro based fuel through the venturi of the carb, and speed the idle up a little more than usual. If you run a hot plug you shouldnt need to keep a glow driver on it when running. Hotter plugs are more fragile though, thinner element wire.

(For the record, I used a 15% BeNol / 85% methanol mix to after-run my high nitro marine engines to burn out any residual nitromethane prior to oiling. They can be harder to start on this mix, but they are set up for lots of nitro and run cold plugs.)

If the carb was tuned for different fuel previously, it will more than likely be out of tune for the new mix. Particularly if nitro was involved.
Rick Vessell likes this.
rc_hydro is offline  
Old 05-31-2022, 11:52 AM
  #14  
Tech Master
iTrader: (28)
 
YoDog's Avatar
 
Join Date: Aug 2006
Location: Gilroy, Ca.
Posts: 1,993
Trader Rating: 28 (100%+)
Default

Originally Posted by 1/8 IC Fan View Post
wont that Pre-ignite the incomming mixture, and therefore not allow decent cycling?
For racing, this can be a problem but for this experiment, it will be fine. Many models use a constant power source on the igniter for ease of running. A glow engine (or diesel), in many forms can run on virtually any fuel. We used to say the can run on "rat farts". Since he will have control over AF ratios via the carburetor and not seeking high RPM, detonation is not likely. I'd say get an inexpensive engine and try things out.
YoDog is offline  
Old 06-03-2022, 03:31 AM
  #15  
Tech Champion
iTrader: (1)
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Virginia, Near DC, USA
Posts: 7,834
Trader Rating: 1 (100%+)
Default

This was already done 80 years ago. RC nitro engines were invented in post-WW2 Europe, which didn't have a lot of resources to spare for hobbyist activities. Nitro engines run on methanol, which is already a biofuel made from fermented cellulose, and lubricated with castor oil, which is also sourced from plants. If you want to get rid of the nitromethane content in commercial nitro fuel to make it 100% plant-sourced, you can do that, you just need to modify the engine to run higher compression.
fyrstormer is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.