Poulan with Header/Muffler
#1
Poulan with Header/Muffler
Hello guys; Here is a pic of my Poulan 46 with a Muffler a fellow modeler friend of mine designed for his IMAC plane with a BME 102. I was getting ready to run the Poulan so I thought "why not" I had welded up several for my friend and had a couple extras laying around so I made up a header and fired it up
With the open header I was getting 6800 with a Zinger 20X10 and 95 db at ~25 feet. Very loud but a sound any motor head would appreciate
With the muffler installed the RPM was 6300 with the 20X10 and the sound was 85 db @ 25 feet. Very nice and at about half throttle the prop noise was louder than the engine.
These were the first runs on the engine and I was pretty impressed with it other than I could not start it by hand flipping?? I could rope start it just fine so I dont know if something minor is keeping it from firing at the lower cranking speeds or is it just the nature of the Poulan??
I need to get an airframe for this motor now. Im going to try and change a few things and make up a muffler that I can firewall mount and run the header down to it.
Adam
With the open header I was getting 6800 with a Zinger 20X10 and 95 db at ~25 feet. Very loud but a sound any motor head would appreciate
With the muffler installed the RPM was 6300 with the 20X10 and the sound was 85 db @ 25 feet. Very nice and at about half throttle the prop noise was louder than the engine.
These were the first runs on the engine and I was pretty impressed with it other than I could not start it by hand flipping?? I could rope start it just fine so I dont know if something minor is keeping it from firing at the lower cranking speeds or is it just the nature of the Poulan??
I need to get an airframe for this motor now. Im going to try and change a few things and make up a muffler that I can firewall mount and run the header down to it.
Adam
#4
Poulan with Header/Muffler
I use a JD2 bender to bend my tubing. The header in the pic is .049 6061 aluminum 7/8 dia. The muffler is 3" dia and 12" long. Im going to try some smaller mufflers with less baffling and see how far I can go before it gets to loud.
Zagnut; Your stuff sounds good if the material is any good. There are a few alloys of aluminum that cannot be welded or dont hold up very well to heat or vibration.
But if I had it I sure would try it too. Its hard to beat free
Adam
Zagnut; Your stuff sounds good if the material is any good. There are a few alloys of aluminum that cannot be welded or dont hold up very well to heat or vibration.
But if I had it I sure would try it too. Its hard to beat free
Adam
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Poulan with Header/Muffler
Adam, that muffler setup looks great. I wonder if you could possibly "tune" the header pipe length to gain top end RPM.
These magneto ignitions do need to be flipped at a fairly fast rate to fire a decent spark. You might try closing the coil pickup gaps a little.
These magneto ignitions do need to be flipped at a fairly fast rate to fire a decent spark. You might try closing the coil pickup gaps a little.
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Re: Poulan with Header/Muffler
Originally posted by ANeat
These were the first runs on the engine and I was pretty impressed with it other than I could not start it by hand flipping?? I could rope start it just fine so I dont know if something minor is keeping it from firing at the lower cranking speeds or is it just the nature of the Poulan??
These were the first runs on the engine and I was pretty impressed with it other than I could not start it by hand flipping?? I could rope start it just fine so I dont know if something minor is keeping it from firing at the lower cranking speeds or is it just the nature of the Poulan??
#7
Poulan with Header/Muffler
Well I tightened up the flywheel gap today down to .010. Im not sure what the spec is on the Poulan 46??
Anyway I got a couple pops but it still wouldnt start. When using the rope it fires right up. Im wondering if my fuel isnt fresh enough and has lost a little of its volatility (sp??) and needs a hotter spark to fire off??
The next time I run it Im going to mix up a fresh gallon and see if that helps.
Volfy; I plan on trying some different lengths. Just waiting on some more tubing to arrive.
Adam
Anyway I got a couple pops but it still wouldnt start. When using the rope it fires right up. Im wondering if my fuel isnt fresh enough and has lost a little of its volatility (sp??) and needs a hotter spark to fire off??
The next time I run it Im going to mix up a fresh gallon and see if that helps.
Volfy; I plan on trying some different lengths. Just waiting on some more tubing to arrive.
Adam
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Poulan with Header/Muffler
I set my gap using a business card. It's a real tight fit, but probably not less than 0.010
Sounds like you have to get the flip speed faster somehow... If the rope trick works, why mess with it.
Sounds like you have to get the flip speed faster somehow... If the rope trick works, why mess with it.
#9
Poulan with Header/Muffler
Yea the rope works nice for now, as long as everything is clamped down to my picnic table. I cant imagine yanking on the rope when the motor is on a plane :stupid:
Seriously; The rope works great for bench running but something else will need to be done so it can be flipped or get a big electric starter.
Has anyone used one if the recoil starters on a Poulan?? I havent cut the stub shaft off the back of mine yet. I had one on a Quadra years ago, just a one way bearing and a big spring.
Adam
Seriously; The rope works great for bench running but something else will need to be done so it can be flipped or get a big electric starter.
Has anyone used one if the recoil starters on a Poulan?? I havent cut the stub shaft off the back of mine yet. I had one on a Quadra years ago, just a one way bearing and a big spring.
Adam
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Poulan with Header/Muffler
I hate to do it, but I'm gonna buy a stronger starter. My old one isn't strong enough. Untill now, the biggest engine I've had to worry about was my friend's .61 Webra.
#12
Poulan with Header/Muffler
I agree Dave; I think the only way I would go for one of the larger starters is if I came across a fantastic deal. It wouldnt take much more for me to go for the ignition. Ive been looking over suitable airplanes right now and playing with the exaust systems.
Adam
Adam
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Poulan with Header/Muffler
This is my first conversion attempt, and a primary factor in the design of the entire plane is to keep costs low.
Gutterpipe fuselage
Coroplast wing
Homemade landing gear
WeedEater® engine
home-made muffler (eventually - still in progress)
Over 95% of this plane was purchased from the NEW LHS (Local Hardware Store). Only the fuel tanks, Tygon and radio equipment is through normal RC sources.
When I do another, I'll probably do electronic ignition. I have to learn to crawl before I start running. Anyone got plans for a homemade electronic ignition system?
Gutterpipe fuselage
Coroplast wing
Homemade landing gear
WeedEater® engine
home-made muffler (eventually - still in progress)
Over 95% of this plane was purchased from the NEW LHS (Local Hardware Store). Only the fuel tanks, Tygon and radio equipment is through normal RC sources.
When I do another, I'll probably do electronic ignition. I have to learn to crawl before I start running. Anyone got plans for a homemade electronic ignition system?
#14
Poulan with Header/Muffler
Originally posted by strato911
This is my first conversion attempt, and a primary factor in the design of the entire plane is to keep costs low.
Gutterpipe fuselage
Coroplast wing
Homemade landing gear
WeedEater® engine
home-made muffler (eventually - still in progress)
When I do another, I'll probably do electronic ignition. I have to learn to crawl before I start running. Anyone got plans for a homemade electronic ignition system?
This is my first conversion attempt, and a primary factor in the design of the entire plane is to keep costs low.
Gutterpipe fuselage
Coroplast wing
Homemade landing gear
WeedEater® engine
home-made muffler (eventually - still in progress)
When I do another, I'll probably do electronic ignition. I have to learn to crawl before I start running. Anyone got plans for a homemade electronic ignition system?
Id like to see plans for a electronic ignition. Anyone tear apart their C&H so they could "reverse engineer" a replica???
Adam
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Poulan with Header/Muffler
Originally posted by ANeat
Hey Id like to see a pic of that plane
Hey Id like to see a pic of that plane
8 foot wing span + 17 inch chord = 1632 sq-in wing (I hope it's not to big)
Current all-up weight (all un-installed parts included) = 10.0 Lbs
Therefore, Wing loading = 14.12 oz / sq-ft
If it flies like I hope, I hope to use it as a trainer (big=easy to see, gas=cheap, 16oz fuel = long flight)
#18
Poulan with Header/Muffler
Dave Ill have to call C&H. I had a little sticker shock when I first looked at their conversion kit for the 46 Poulan. I dont need the carb mount; prop adapter or other stuff and the price on just the ignition isnt to bad.
Dennis; the Spad is pretty cool, did you go for the yardstick for a spar or something else?? Ive got one of those 25's I think I got it out of a Craftsman weed trimmer. Ive done most of the conversion but havent ran it yet.
Adam
Dennis; the Spad is pretty cool, did you go for the yardstick for a spar or something else?? Ive got one of those 25's I think I got it out of a Craftsman weed trimmer. Ive done most of the conversion but havent ran it yet.
Adam
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Poulan with Header/Muffler
Adam - I was concerned that yard-sticks might snap during a pull-out from a dive. Instead, I used Coroplast on edge, several layers (4 in the center, tapering in layers towards the tips). If the stress gets to much, the spar can flex somewhat. To further reduce the chance of "snap" manouvers, I used the slow 100oz-in GWS servos (0.33s transit for 60º) for everything but the throttle.
What's your opinion - will it fly? Is a 25cc Poulan enough?
P.S. I added some specs to my earlier post with the pics.
What's your opinion - will it fly? Is a 25cc Poulan enough?
P.S. I added some specs to my earlier post with the pics.
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Poulan with Header/Muffler
Originally posted by ANeat
Try a PBF; Now there is an airfoil :stupid:
Try a PBF; Now there is an airfoil :stupid:
#23
Poulan with Header/Muffler
Originally posted by strato911
What size PBF would be appropriate for a 25cc Poulan?
What size PBF would be appropriate for a 25cc Poulan?
I would like to watch that :spinnyeye
Adam
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Poulan with Header/Muffler
Egads! The Canadians have gotten a hold of our stealth technology!
Anyway, I've heard it said that as long as you got a good motor pulling up front, you can fly with an airfoil shaped with your wife's high heels.
Anyway, I've heard it said that as long as you got a good motor pulling up front, you can fly with an airfoil shaped with your wife's high heels.
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Poulan 25cc
Volfy - you seem pretty knowledgable about these conversions. How many HP can I expect from a 25cc? The LHS suggested (and sold) a 15X8 Master Airscrew for break-in. What should I use afterwards? What kind of RPM's can I expect? Do you think my "Blue Heron" will fly?