Cox Engines Forum
You are not logged in! Please login or register.

Logged in members see NO ADVERTISEMENTS!


Dukes Mixture Cox_ba12




Dukes Mixture Pixel

Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» Golden Bee basic running problem
by roddie Today at 10:51 pm

» Simple Gliders
by rdw777 Today at 6:25 pm

» Foam hand kids glider converted to 0.049 CL
by rdw777 Today at 6:11 pm

» Weird search for a single comic from an old Mad Magazine
by Kim Today at 1:44 pm

» Scientific "Zipper" Build...Zipper Flys!.
by getback Today at 7:27 am

» Cox .049 Tee Dee engines back in stock (limited availablility)
by GallopingGhostler Today at 1:05 am

» Very off-topic.........Time passes and not always for the best......
by rsv1cox Yesterday at 2:47 pm

» Roddie-Rigger.. a 2005 original design
by roddie Wed Jul 24, 2024 11:48 pm

» Jim Walker Bonanza etc.
by rsv1cox Wed Jul 24, 2024 6:30 pm

» Throttles for Cox Tee Dee .049 / .020 / .010 engines --- videos
by sosam117 Wed Jul 24, 2024 8:54 am

» Introducing our Cox .049 TD Engines
by Admin Tue Jul 23, 2024 2:00 am

» Project Cox .049 r/c & Citabrian Champion
by getback Mon Jul 22, 2024 4:14 pm

Cox Engine of The Month
July-2024
robot797's

"ULTIMITE COX 010: it has a clutch, E starter, throttle, exhaust, aluminum tank, aluminum venturi, gearbox with forward and reverse, and now its on a custom drawn and printed stand"



PAST WINNERS
CEF Traveling Engine

Win This Engine!
Gallery


Dukes Mixture Empty
Live on Patrol


Dukes Mixture

Go down

Dukes Mixture Empty Dukes Mixture

Post  crankbndr Mon Jul 01, 2013 8:59 am

I have been studying the transition from spark ignition to glow in the late 40s and was wondering how you found the best nitro content for a fixed compression engine.

http://www.modelenginenews.org/~modeng74/index.html

The link did not work, this is the page.

Dukes Mixture Scan10


Last edited by crankbndr on Mon Jul 01, 2013 9:47 am; edited 1 time in total
crankbndr
crankbndr
Top Poster
Top Poster

Posts : 3087
Join date : 2011-12-10
Location : Homestead FL

Back to top Go down

Dukes Mixture Empty Re: Dukes Mixture

Post  pkrankow Mon Jul 01, 2013 9:25 am

By the 40's internal combustion had been around a rather long time. Many different fuels had been experimented with and look-up tables for compression ratio vs fuel and additives had been established. Knowing the desired fuel, a compression ratio is decided upon for suitable performance. This can also be worked the other way, such as converting a spark engine to glow.

Also there is no such thing as "fixed" compression ratio. It can be adjusted by shimming on almost any engine there is. (which does involve taking the engine to pieces, so OK, fixed, not adjustable while operating.) The point is, the design can be adjusted after it is built so it functions best on the desired fuel.

http://en.wikipedia.org/wiki/History_of_the_internal_combustion_engine

Phil
pkrankow
pkrankow
Top Poster
Top Poster

Posts : 3025
Join date : 2012-10-02
Location : Ohio

Back to top Go down

Dukes Mixture Empty Re: Dukes Mixture

Post  crankbndr Mon Jul 01, 2013 10:20 am

The use of nitro in model engines was pioneered by the Dooling brothers and Ray Arden about the same time the glow head came around, late 40s.
Even before full size racers started using nitro, this was uncharted territory for modelers at the time.
crankbndr
crankbndr
Top Poster
Top Poster

Posts : 3087
Join date : 2011-12-10
Location : Homestead FL

Back to top Go down

Dukes Mixture Empty Re: Dukes Mixture

Post  pkrankow Mon Jul 01, 2013 11:36 am

I don't doubt the time that nitromethane was used in model, or any engines, in the public eye.  The oldest source I find for nitromethane is about 1911.

https://www.google.com/patents/US1015691?pg=PA1&dq=nitromethane&hl=en&sa=X&ei=vKzRUbSNEIOyyAH

I believe the compound was first isolated long before this.

The use as a fuel in racing cars (drag racing) started in the 1930's.  It sounds like the development of engines paralleled in both auto racing and modeling.

Phil

For reference nitroglycerin was synthesized in 1847,
http://en.wikipedia.org/wiki/Nitroglycerin

pkrankow
pkrankow
Top Poster
Top Poster

Posts : 3025
Join date : 2012-10-02
Location : Ohio

Back to top Go down

Dukes Mixture Empty Re: Dukes Mixture

Post  gcb Sun Jul 07, 2013 12:07 pm

For our purposes there are several things we can adjust for the "perfect" run. Prop size, for the particular airframe it is pulling, at the velocity we want to pull it. We can adjust nitro content...which affects power AND affects how long we can run on a given amount of fuel...for those timed events. We can adjust venturi size (on some) which affects power and fuel draw. We can adjust glow plug heat ranges...to coincide with nitro changes. and finally we can adjust head shims... to fine tune the firing timing to coincide with all the other stuff. These things are adjusted to coincide with altitude, temperature and humidity changes.

For most of us in a non-competition environment, ballpark ranges are good enough.

Some "expert" flyers know just what to adjust for a flight and need to be consistent to get maximum performance. I guess that's why they are experts. :-)

George
gcb
gcb
Platinum Member
Platinum Member

Posts : 908
Join date : 2011-08-11
Location : Port Ewen, NY

Back to top Go down

Dukes Mixture Empty Re: Dukes Mixture

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum