Proper Stinger Inside Diameter?

[glenng]

I have a AB 67 quiet pipe that has a stinger inside diameter of .466" . It has a small hole that may have been made to keep smaller bushings in place. Just wondering what would be the best stinger Inside diameter on a 1/8 scale boat @ sea level?

Thanks,

Glenn

 

[shoboat]

Glenn,

I would just go testing with a few stingers and see what works the best with your set up.

There are going to be a lot of variables as far as: load, friction, % of fuel, pipe length, etc.

Andy made that pipe so it could be adjusted for different conditions.

Go Have Some Fun Testing,

Mark Sholund

 

[glenng]

Glenn,

I would just go testing with a few stingers and see what works the best with your set up.

There are going to be a lot of variables as far as: load, friction, % of fuel, pipe length, etc.

Andy made that pipe so it could be adjusted for different conditions.

Go Have Some Fun Testing,

Mark Sholund

Mark, there will not be any open water here till the winter rains come and refill the lakes. I was just looking for a "ballpark figure". Pipe has not been cut- fuel @ 50%

 

[Ray Sametz]

Glenn, just for reference.....http://www.intlwaters.com/index.php?showtopic=56259

 

[glenng]

Thank you VERY much Ray for that link. I'll be sending a p.m. soon.

Glenn

 

[Dasboatman]

Hey Guys.

Key words and tricky phrase in the question asked was:

"CMB 67 with AB 67 muffled pipe, in a Scale boat, at sea level."

I vote with GeorgiaScaleboater. And he actually races this configuration, Glenn.

Run the bowl volume as CMB has designed in the engine.
Head clearance .016-.018" pipe length for the CMB/AB muffled pipe 11-3/4" Center of cylinder to seam bead on pipe.

CHEERS !!! Bob

 

[Don Ferrette]

Hey Glenn, honestly there is no one magic number as it depends on a whole lot more than just an AB67 quiet pipe at sea level. Typically I'll tell guys to start at 12" length on the pipe and about .450" on the stringer then go from there as it's best to start off with a setting that will get you off the beach and a little long on the pipe length will generally do that. Not to mention I've seen some fast scales that run pipe lengths of 12" or even a tad longer but couldn't go at 11.75", it was what was best for the particular set up of the boat. There is no "one size fits all" when setting up a scale powerplant to yield the best performance AND reliability. Try a few different stinger diameters, different pipe lengths and props too as a few trips to the pond for some "test sessions" will be well worth it in the long run. Mark's recommendations are more accurate as every scale is different, even the same brand of hull between two different owners. I've raced and helped set up many scale boats over the years and every single one was unique in what worked the optimum for that particular boat at the time. Good luck with it my friend.