Engine basics > Engine set up tips

PIPE Chart List Setup

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Ted Fancher:
Randy,

Am I just getting more advanced  Old Timers or did I really used to find that terrific chart of engine types and RPM and Pipe tuning length real easily.  I've been looking for it the last couple of days on your fora and the Aero Products web site and can't find it.     Was I really imagining it??   Where'd it go????

Ted

Don't tell me you've ditched pipes for batteries!  The wussification of America gets closer every day.  Real men have at least one once bloody digit and impaired hearing.

RandySmith:
Hi Ted

Nope  I am still making smoke the old fashion way :-)

I will send you the chart, I am not sure the post will work here, if so I will post it

Randy



             PIPE     TUNING        CHART by   Randy Smith         
                        
   MEASURE taken    from  the   GLO-      PLUG  to  FIRST   BAFFLE                        
   FOR THE P.A. 40 - 61 ENGINES and many others, see timing chart                     
   A Good PIPE Starting Point         16 3\4to 17.5 inches      PROPS 11,5 FOR THE 40,12 FOR THE 51      
   12.5 to 13 INCHES FOR THE 61 3.8 TO 4 PITCH  10,500-11,200 RPMs   For the 61 @      3.8 PITCH    10,500 -11,200 RPM         
   IF  IT IS  TOO HOT OR COMES ON TOO STRONG  MOVE  OUT  toward 17.5  INCHES                     
                        
   IF PLANE SPEEDS UP DURING THE FLIGHT MOVE PIPE OUT ,                     
   IF PLANE SLOWS DOWN DURING FLIGHT MOVE PIPE IN SHORTER                     
best props pipe combo lenghts                        
40   bolly 11.75 x 4.25  cut to 11.3-11.5 inches         pipe 16.75            
51   bolly 12 x 4.25 3 blade as is     bolly 12.2 x 4.2 2 b;ade as is               pipe 17 in to 17.25      
61   12x 4.25 3 blade  13 x 4.5 3 blade  cut to 12.5   or  13 x 4.5  2 blade  as is                  pipe 17 to 17.5   
65   bolly 13 x 4.5 3 blade or  13.75 x 4.5  3 blade            pipe 17.25 to 18         
75   bolly 13 3\4 and 14 inch 3 blades 4to 4 3\4 pitch Bolly 14 to15x 4.5 2 blade            pipe  18 to 19.5         
                        
   Do NOT flip motor over dry or without oil and fuel going thru them                     

Timothy Payne:
There's a book called Two-Stroke Performance Tuning by A. Graham Bell.

Tells you everything you need to know about tuning strokers including expansion chamber dimensions.

Walter Kaaden was the man behind the theory of tuning a two stroke in this way, and during his time with the MZ racers of the sixties, they were the first to break the 100bhp per litre stat with their unbeatable 250s.

A brilliant engineer, and father of the modern two stroke,


Tim

Rob Duckering:
If you follow Randy's chart, you will have the best engine run.
I remember when I was flying an SV-22 (in my avatar) with a PA 65 and someone remarked it sure has the "perfect stunt engine run", I just mentioned at the time, 'I just did what Randy said in the chart'
Pretty simple actually, kinda like reading the directions instead of trying to re-invent the wheel.

steven yampolsky:

--- Quote from: Rob Duckering on January 09, 2014, 11:55:57 AM ---If you follow Randy's chart, you will have the best engine run.
I remember when I was flying an SV-22 (in my avatar) with a PA 65 and someone remarked it sure has the "perfect stunt engine run", I just mentioned at the time, 'I just did what Randy said in the chart'
Pretty simple actually, kinda like reading the directions instead of trying to re-invent the wheel.

--- End quote ---

The only problem is figuring out exhaust timing of a OS 40VF  LL~

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