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-   -   77DF pipe size? (https://www.rcuniverse.com/forum/extreme-speed-prop-planes-104/9094197-77df-pipe-size.html)

RVman 09-14-2009 07:36 AM

77DF pipe size?
 
Hi there, I have the OS77 fan engine and would like to know what size pipe to use on it. Macs 10cc is for 60-75 and the 15cc pipe is for 90-120's so I'm not sure which one to look for.

Thanks,

r-c-guy 09-14-2009 09:12 AM

RE: 77DF pipe size?
 
Try to find a 13 cc marine pipe. ll be the best

freakingfast 09-14-2009 08:21 PM

RE: 77DF pipe size?
 
Macs 13 cc marine or 15 cc aerotuned. For DF & performance marine engines, go one size up from normal engine pipe sizes. Too small and it'll run hot and blow plugs like crazy.

RVman 09-14-2009 08:38 PM

RE: 77DF pipe size?
 
thanks FF, what you describe sounds like what my picco 45 does if not tuned exactly perfect. The 77 is also going into a screamin demon so we shall see how that turns out.

MJD 09-14-2009 09:16 PM

RE: 77DF pipe size?
 
Next chance you get (spring?), I have a 10cc open pipe (1160..?) you can check out on your .45. Also have the West .50 pipe but it's kind of heavy, but one or the other might be good to test it's want for larger volume pipes.

MJD

lfinney 09-14-2009 09:56 PM

RE: 77DF pipe size?
 
the 1365 would work spot on for the 77 os, the picco 45 df motor #1345 pipe, these are the compund cone design, and work well with high nitro and high rpm motors, but please no sniveling iff they seem a lil abrupt when the get on pipe:D, be ready to fly... alot of boaters who switched to these, were very impressed with the speed gains[8D]

smoknrv4 09-15-2009 12:25 AM

RE: 77DF pipe size?
 


ORIGINAL: RVman

Hi there, I have the OS77 fan engine and would like to know what size pipe to use on it. Macs 10cc is for 60-75 and the 15cc pipe is for 90-120's so I'm not sure which one to look for.

Thanks,
Hi there RVdude, what did you have in mind for this engine?:D[8D]

freakingfast 09-15-2009 01:05 AM

RE: 77DF pipe size?
 

ORIGINAL: lfinney

the 1365 would work spot on for the 77 os, the picco 45 df motor #1345 pipe, these are the compund cone design, and work well with high nitro and high rpm motors, but please no sniveling iff they seem a lil abrupt when the get on pipe:D, be ready to fly... alot of boaters who switched to these, were very impressed with the speed gains[8D]

The 1365 (11 cc) seems a bit small for the 77. Id be leaning towards a 13 cc marine. A # 1250 aero (8.5),(What I use) should be fine for a 45/46 df engine.

RVman 09-15-2009 09:20 AM

RE: 77DF pipe size?
 


ORIGINAL: smoknrv4

Hi there RVdude, what did you have in mind for this engine?:D[8D]
another SD, MJD's idea though.

MJD 09-15-2009 10:32 AM

RE: 77DF pipe size?
 


ORIGINAL: RVman



ORIGINAL: smoknrv4

Hi there RVdude, what did you have in mind for this engine?:D[8D]
another SD, MJD's idea though.
Both you made the mistake of telling me you had big block DF engines - the nagging has never stopped since.. :D

MJD

RVman 09-15-2009 03:53 PM

RE: 77DF pipe size?
 
it will be done in the spring, or maybe Christmas when I'm back in southern ontario. Just need a nice december day and we could fly it then. I kinda want to find a muffled pipe for this one so it might be allowed at the local club.
oh btw Mike, I managed to get a 12oz tank in this version. Should provide about 4 or 5 min flight time or so.

RVman 09-19-2009 02:19 PM

RE: 77DF pipe size?
 
Another question about the tuned pipe. There is a stub on the exhaust with an o-ring. I assume the pipe is intended to fit over that stub. But am I supposed to have a header pipe as well? I may think about making a pipe, I have lots of sheet metal equipment and aluminum here at school and a book on pipe design. If it doesn't work (likely) than I won't be out any money and will learn something along the way.

lfinney 09-19-2009 02:26 PM

RE: 77DF pipe size?
 
you need several inches of straight tubing between the stub adapter and the pipe, try three inches to start

freakingfast 09-19-2009 03:38 PM

RE: 77DF pipe size?
 


ORIGINAL: RVman

Another question about the tuned pipe. There is a stub on the exhaust with an o-ring. I assume the pipe is intended to fit over that stub. But am I supposed to have a header pipe as well? I may think about making a pipe, I have lots of sheet metal equipment and aluminum here at school and a book on pipe design. If it doesn't work (likely) than I won't be out any money and will learn something along the way.

I think # 3930, 3931 or 3932 is what you are looking for:
http://www.macspro.com/headers_rear.asp

RVman 09-19-2009 04:39 PM

RE: 77DF pipe size?
 
FF yes it is, thanks. I need a fuse top style to clear the fuel tank.


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