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Engine basics => Engine set up tips => Topic started by: John Leidle on May 27, 2016, 10:48:24 PM

Title: Pipe Length RO JETT .67 - 76
Post by: John Leidle on May 27, 2016, 10:48:24 PM: I'd like everyone to put down their pipe length for their setup . I have Dave Tribles & Joe Gilbert's but I'd like more guys to post their's. So Pipe length & venturi size would be appreciated.
John
Title: Re: Pipe Length RO JETT .67 - 76
Post by: Randy Cuberly on May 28, 2016, 02:37:08 AM: I haven't run my 67 on a pipe yet so I'm a little curious for settings for that also. My current plans for the 67 is on a header muffler in my Collossus (classic).

My 76 runs at 18.25 inches at 9600 RPM at launch with a Randy PA 75 pipe, and uses 7.25 oz of 18% nitro and 18% oil (15% Klotz and 3% Castor). I fly at 2300 ft altitude in Tucson AZ. (Hot sometimes). Engine runs cool. Glow plug is Enya #3, prop is Mejlik 13-4.25 three blade (narrow blade), 68 ft 18 thou lines.

Randy Cuberly
Title: Re: Pipe Length RO JETT .67 - 76
Post by: John Leidle on May 28, 2016, 07:58:30 AM: Thanks Randy. Is the venturi stock ?
Title: Re: Pipe Length RO JETT .67 - 76
Post by: Randy Cuberly on May 29, 2016, 02:10:56 AM: Quote from: John Leidle on May 28, 2016, 07:58:30 AM
Thanks Randy. Is the venturi stock ?

Sorry... No it's not stock. It's .006 larger than stock, but has one layer of panty hose over it! I typically trim this way. Keeps out the pebbles too! It does not have a "spigot". I tried that but found it temperamental to tune. I realize a lot of the "big boys" use the spigot but it didn't seem to work on this particular engine for me. It might have if I had spent more time fiddleing with it but I simply went back to the afore mentioned setup because it worked very well and was very easy to deal with. I would imagine that at sea level things might be a bit different and a smaller venturi might work better. I would mention that it regulates very well with this setup and a bit better than others that I tried without the pantyhose which probably indicates that a slightly smaller venturi coul be used even here!

Randy Cuberly
Title: Re: Pipe Length RO JETT .67 - 76
Post by: big ron on May 29, 2016, 08:23:03 AM: John could you give Dave and Joe's setups for us
Title: Re: Pipe Length RO JETT .67 - 76
Post by: John Leidle on May 30, 2016, 12:12:41 AM: Ron , this is the info I recieved from the afore mentioned users,,, if I write something that is false I only wrote what info I recieved, Joe sets his .76 up with a .205 venturi & the pipe is set to 19.25" Dave has a .205 venturi & the pipe is set at 21.5".
Title: Re: Pipe Length RO JETT .67 - 76
Post by: big ron on May 30, 2016, 07:00:33 AM: Thanks just looking for info on how long to make the tunnel to pipe don't want to not leave enough
Title: Re: Pipe Length RO JETT .67 - 76
Post by: Dave_Trible on May 30, 2016, 09:01:52 AM: Quote from: John Leidle on May 30, 2016, 12:12:41 AM
Ron , this is the info I recieved from the afore mentioned users,,, if I write something that is false I only wrote what info I recieved, Joe sets his .76 up with a .205 venturi & the pipe is set to 19.25" Dave has a .205 venturi & the pipe is set at 21.5".
Hi John. A little difference, Joe uses the .67, and I the .76. I get a two inch pipe difference between the .61 and the .76- using the same prop and roughly the same RPM. The pipe for the .76 is also larger in diameter.

Dave
Title: Re: Pipe Length RO JETT .67 - 76
Post by: big ron on May 30, 2016, 05:14:30 PM: I'm gonna be using the 67 thanks for the info