stunthanger.com
Engine basics => Engine set up tips => Topic started by: Bill Little on April 09, 2006, 12:58:41 PM
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Hi Randy,
I think it would be a good idea (kinda like the "stunt fuel" article you reposted) if you posted you "basic set-up" for the PA engines on pipe. Pipe length, props, fuel, etc., just the general first flight set up so everyone would know the base line.
I know it works and is repeatable, so it might head off any problems that the "first time" user might experience, and kill some of the "mystique" about pipe usage that the newer guys may feel.
What 'cha think?
Bill <><
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Bump 8)
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BUMP j1 x:
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EX-TIMING AERO 40\51\61\65 AERO 75 & 85 OPS/OS/ST OPS/OS/YS OS/YS
RPM 130degree 135degree 133 degrees 140degree 145degree 150degree 155degree
9000 18 1/2 18.5-18.75 18.3-18.7 19 5/8 20 1/4 20 7/8 21 1/2
9500 17 3/4 17 3/4 -18 17.1.4-17.9 19 19 5/8 20 3/8 21
10000 17 5/16 17.5-17.25 17.25-17.5 18 3/8 19 19 3/4 20 1/2
10500 16 3/4 17-17.25 16.9- 17.2 17 7/8 18 5/16 19 19 7/8
11000 16 5/16 17-16.75 16.7 17 17 5/16 17 7/8 18 5/8 19 1/4
11500 16 16 5/16 16 3/4 17 3/8 17 3/4 18 3/4
12000 15 3/4 16 1/8 16 3/8 16 3/4 17 1/2 18 1/8
12500 15 3/8 15 3/4 16 1/16 16 3/8 17 17 5/8
13000 14 7/8 15 3/8 15 9/16 16 16 1/2 17 1/8
13500
PIPE TUNING CHART by Randy Smith
MEASURE taken from the GLO- PLUG to FIRST BAFFLE
FOR THE P.A. 40 - 61 ENGINES
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 ( normally the back half)THE FLIGHT MOVE PIPE OUT ,
IF PLANE SLOWS DOWN DURING (normally the back half of the flight)FLIGHT MOVE PIPE IN SHORTER Make sure the fuel tank is good and not causing any slow down or speed up problems before moving pipe
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 to 17.5
75 bolly 15 x 4.7 2 blade ,13 3\4 and 14 inch 3 blades 4to 4 3\4 pitch Bolly 14 to15x 4.5 2 blade pipe 17.25 to 17.75
This is a tuning-timing chart for Several engines
I will write more when I get a little time
Randy
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Randy, when running a pipe set up, what is best, Uniflow, standard vent or pressure.
Thanks
Wayne
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Hi Wayne
You see many types used but the most common is uniflow suction, I would advise against pressure on any motor and setup unless you just have to have it to work.
most everyone has gone off of pressure for pipe setups
Randy
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Randy, thanks for the info.
Wayne
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Randy,
I have been running the 75 on a bolly 13.75 3 bl. It is pitched up a bit. The motor is very happy at 8700 rpms. I am thinking my pipe length should be about 18.5-19" range. Will this be sufficiant to hold the motor off should it want to wind up in the wind?
The reason I ask is because right now I dont have enough pipe coupler to get the pipe longer than 17.5 and if there is any wind with this higher pitched prop it winds up something awful. But in calm conditions the motor at 8700 is in a BIG FAT 4 cysle all the way through and very steady.
In the old days of the 65 I ran a 12" 4 blade at 3.6 sataion 8-3.2 last station and it would fly the same spped no matter what was going on. I had the pipe in about 17.125 and the rpms up to about 10500-10750. On calm days leave the same prop on and screw it in to 11000 and it would fly the same exact flight but have more in the corner. But the prop was so flat it was a giant break on the motor. It could reva nd rev and go nowhere.
I want the same type of breaking action from the pipe on my 75 but with long props with a little higher pitches. Will I get it?
I know I may need to pitch down a little to come in around 9200 I am thinking that is a good number.
Your thoughts please.
Thanks in advance.
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Hi Doug
You will need to run a 19 inch pipe at that RPM, you will get better results setting up on lower nitro fuel if you want to not wind up running in a deep 4. If you run high nitro with that setup you will get some wind up in the wind.
I would suggest setting up at 9,000 , that should be about 4.4 pitch , the motor will make good HP with 5% fuel, and you can go up some when the Heat really gets here.
I ran a 13.5 3 blade last summer on the 75 at 4.3 pitch 5% fuel on the Intrepid, It just beeped barely at the
tops of the maneuvers and had almost no windup. It was 98 degrees and 95% humidity, still had great power.
by the way you can use a piece of header pipe to extend the pipe Lenght too
let me know how its going
Randy
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Randy,
I have been using 5% nitro with excellent results. The higher nitro was giving me run problems. I went away from that. I will run the longer pipe and let you know how it works out.
Thanks
Doug
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As a piped powertrain rookie a couple seasons ago, I have to say that the chart information and a couple of conversations were as close to plug and play as one could ask for. MUCH simpler than messing with an old FP35 or such.
The problems can crop up when one cannot resist the temptation to mess with the setup!!
I set my pipe length to 17-1/4 and have never moved it since day one. Once we got the engine broken in, set the prop pitch for lap speed and off it went.
Never really twiddle the needle much either---simple move up or down with the Nitro content as the days heat up and the humidity comes in.
FWIW
Curt
Katana/PA65/Pipe