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

Logged in members see NO ADVERTISEMENTS!


Run times with Various Heads Cox_ba12




Run times with Various Heads Pixel

Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» *Cox Engine of The Month* Submit your pictures! -August 2021-
by balogh Today at 12:47 am

» General TD 049 Assembly
by dckrsn Yesterday at 10:07 pm

» What RTF plane is this from?
by dckrsn Yesterday at 9:38 pm

» Testors P 51 Mustang, how to disassemble?
by rgbolen Yesterday at 9:10 pm

» Ohisson & Rice what-ever and Champion V (3/8" by 24 tpi) arrives
by rsv1cox Yesterday at 3:47 pm

» A Flying Clown Friday (and Sunday)
by getback Yesterday at 8:38 am

» Cox RTF Wheels
by rsv1cox Yesterday at 8:27 am

» Cavacraft Fokker D-7
by rsv1cox Yesterday at 7:56 am

» Oh Deere............
by rsv1cox Yesterday at 7:36 am

» 049 Black Widow tuning
by --Oz-- Yesterday at 1:00 am

» Lost engine Even worse From california dan !!!!
by Cribbs74 Sun Aug 01, 2021 8:54 pm

» Wanted: Sullivan "Insta-Just" #2 Control Line Handle(s)
by Ken Cook Sun Aug 01, 2021 6:57 pm

Cox Engine of The Month
July-2021
Kim's

"Rusty's RR-1 runs up on the Q-Tee on a beautiful Summer S.M.A.L.L. Day."




PAST WINNERS
CEF Traveling Engine

Win This Engine!
Forum Store
CEF Ear Savers
Gallery


Run times with Various Heads Empty

Run times with Various Heads

Go down

Run times with Various Heads Empty Run times with Various Heads

Post  Iceberg Wed Oct 07, 2020 10:54 am

Just was curious. Does anyone know.

I know that the head inserts with OS Number 8 runs slower than cox high compression head by about 3-4 K RPM. I know the Merlin 2019 head runs almost the same as the original Cox head.

I'm in quarantine right now as a precaution so can't get out for actual comparison test hence the question to you.

The head adaptor that is slower by 3-4 K does it use less fuel? I mean does it pick up run time due to the lower RPM? I never tested that before. Normal runs for 17K are like 2.5- 2.75 minutes per tank. Might the slower head run time achieve an additional 60+- seconds of "slower" run or at least proportionally to its comparable high compression head run?

Anyone have any stats or experience to share?

Thanks
Iceberg
Iceberg
Iceberg
Gold Member
Gold Member

Posts : 347
Join date : 2018-11-03
Location : Bangkapi Thailand

Back to top Go down

Run times with Various Heads Empty Re: Run times with Various Heads

Post  davidll1984 Wed Oct 07, 2020 11:12 am

It make sense To me as the engine wil breath faster and stronger tink it can afect the flight time
davidll1984
davidll1984
Diamond Member
Diamond Member

Posts : 1445
Join date : 2020-02-12
Age : 36
Location : shawinigan

Back to top Go down

Run times with Various Heads Empty Re: Run times with Various Heads

Post  aspeed Thu Oct 08, 2020 5:38 pm

Common knowledge is that a tighter combustion chamber gives the best mileage. Smaller place for the fuel to fit. More efficient as well. In practise, a smaller prop is used, so it revs more which wastes fuel. I would think that a huge load prop with a TD head would give the best run time---if it will run reliably. Sometimes they will just flop back and forth. I have not tested it though. Just my thoughts.
aspeed
aspeed
Platinum Member
Platinum Member

Posts : 577
Join date : 2013-01-18
Location : Leamington Ont. Can.

Back to top Go down

Run times with Various Heads Empty Re: Run times with Various Heads

Post  dckrsn Thu Oct 08, 2020 5:57 pm

@aspeed wrote:Common knowledge is that a tighter combustion chamber gives the best mileage.  Smaller place for the fuel to fit.  More efficient as well.  In practise, a smaller prop is used, so it revs more which wastes fuel.  I would think that a huge load prop with a TD head would give the best run time---if it will run reliably.  Sometimes they will just flop back and forth.  I have not tested it though.  Just my thoughts.
I absolutely concur aspeed. I've had engines that would do the back and forth flop due to over compression. I'd use an electric starter on them, and the they run like a scalded something(my cat's in my lap). Same goes for under compressed engines(clapped out).
Granted, I wouldn't make a habit of starting with an electric starter, without the usual prop plate/case shim in place.
Bob
dckrsn
dckrsn
Diamond Member
Diamond Member

2019 Supporter

2020 Supporter

Posts : 2690
Join date : 2010-10-21
Age : 68
Location : Long Island, New York

Back to top Go down

Run times with Various Heads Empty Re: Run times with Various Heads

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top


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