Know nothing about trimmer engine conversion - Page 3 - RC Groups
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Nov 11, 2012, 11:27 PM
Registered User
earlwb's Avatar
They use a pumper carb, so they do not use muffler pressure like they do with glow engines.
If the pump is working pretty good, you can place the fuel quite a ways away from the engine and it'll still work. Yeah that Torquemaster 1.80 should be able to do it, but I never tried one myself yet. I use a good pair of gloves, more to prevent the prop from cutting my hand and also to help take some of the sting out of a prop strike.
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Nov 11, 2012, 11:38 PM
The Shindaiwa T2510 has a 4-cycle engine that runs on pre-mixed fuel. Nobody is probably going to gut a $400 weedeater for the motor, but it's interesting.
Nov 12, 2012, 07:49 AM
Registered User
I've been using a paint roller recently. Seems to work pretty good. I know it saved my fingers working on a rcgf20cc last week. I have a carb problem with it and got several back fires that would have hurt. Its next in line for the work bench.
Nov 12, 2012, 08:07 AM
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earlwb's Avatar
Using a paint roller as a chicken stick is a pretty good idea.
Thanks for sharing that tip.

Actually when they started advertising that Fuji four stroke RC engine for $895, it does make it attractive to take apart a Shindaiwa to convert it for RC use. Even the Saito gas engines aren't all that inexpensive either. The Kolm and Rotomotor four strokes aren't inexpensive either. The Rotomotor four stroke is going for $775 at this time.
Nov 20, 2012, 10:07 PM
Registered User

what plane fit with them

hey, actually my engine was really bad , it didn't even want to start so i cleaned the carb and put new gas lines and diaphragm, and adjust it, the hardest part was to adjust low rate and high rate screws, because they are pacman style, but i took a metal saw to make lines on them so i can adjust them with a flat screwdriver, anyway. but now i wonder, and i have seen that some people got the engine so light that they could even do 3d and aerobatic.. so what can i remove on that? , would it be wiser to remove the exhaust and put an rc one ? the other issue with it is , i would need a big prop because the engine is so big that it will hide most of wind created.. ..


can i remove enough weight so i could make aerobatic ?

if yes . what can i remove on it(look at picture) ?

would it be better to put a regular rc plane exhaust or tuned pipe?
Nov 20, 2012, 11:28 PM
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earlwb's Avatar
One could probably strip off some more things, such as all that stuff around the carb, but it may not really reduce the weight much if any. The mufflers are primarily replaced with better ones that reduce the noise more, or increase the power more (such as tuned muffler or pipe systems). But if the muffler is steel and heavy, then going with a more lightweight muffler, maybe aluminum can help. There might be some extraneous protrusions or metal webbing on the crankcase that could be cut off too. But don't chop off the mounting tabs or mount points though.

Further weight reduction entails removing the flywheel and magneto and replacing them with a electronic CDI unit that is battery powered. But quite a few fellows prefer the magneto systems, even if they weigh more, for the simplicity of it all. More advanced is machining up a new crankcase for the engine to replace the stock heavier one.

The side piston port engines run pretty good, but the side port forces the engine designer to leave off a intake boost port into the cylinder. So the engine only has two side ports. The reed valve engines or rotary valve engines have the carb away from the side of the cylinder, so then they can put in a third intake port into the cylinder. Thus the reed valve or rotary valve engines develop more power and performance than the old style side port engines do. Thus your side port engine won't run as good as the other types of engines, and won't really develop that extra power that the 3D aerobatics crowd likes. But the engine is good for other types of model airplance flying of course.
Nov 23, 2012, 02:54 PM
Registered User

prop hub

thank you, i got another question , its about the prop hub , a made one but the thing is that i think the screw should be inveter , ( left hand) . but that part is on i could just buy one i found some of these, but i have to change the which i screw it in , what a mess , is there a place where i can buy a prop hub taht would fit ? , not to expensive? .

thank you
Nov 23, 2012, 02:56 PM
Registered User
the prop was getting of each time i was starting it with the drill .. it could of hurt somebody
Nov 24, 2012, 10:54 PM
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earlwb's Avatar
I think your problem is that the prop hub needs to be a larger diameter to match the width of the propeller at its hub. You don't have enough surface area to grip the prop well, so it slips and comes loose on you. You should also cut in some grooves to grip the prop better. The prop washer should be larger in diameter to match the prop hub size too and more thick than a regular washer. Even a gas engine RC conversion develops too much power for using a couple of nuts with the prop in between them. The prop hub can have a wide end with a tapered or stepped smaller diameter rear part though.

You can see here where I made the prop hub adapter larger in diameter and used a big washer like spacer for the prop washer too.
Last edited by earlwb; Nov 24, 2012 at 10:56 PM. Reason: needed to add more information
Nov 24, 2012, 11:10 PM
Registered User
yes, i will look for bigger washers, thank you , would only bigger washer and cutting prop diameter to make more grip would be enough? and i know that i should change the screw, and i found some of theme, because when the drill spin to start the engine , it goes counter clock and it unscrew the screw which makes the prop getting off.
Nov 24, 2012, 11:12 PM
Registered User
like making the same prop hub as i took and just putting bigger washers and maybe more thick or more? i mean
Nov 25, 2012, 07:10 AM
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earlwb's Avatar
If you use a thick steel washer as big as the hub on the propeller and weld it onto the rear nut, it may work OK. Then use a thick front washer to match but don't weld it to the front nut. A 1/4 inch thick rear washer maybe even a little more thick, as you don't want it to flex back from the pressure from the nuts tightening down on it. Use a 1/8 to 1/4 inch thick front washer.

The reason the engines drive prop hub is so wide is to provide a larger surface area for friction to grip the propeller with and also to not flexof bow back from the pressure against it from the front prop nut when it is tightened down on it.
Nov 27, 2012, 04:30 PM
Two left thumbs
It was stated above that piston ported engines can't have a third port as is typical of Schneurle ported engines. While true, some commercial grade two stroke lawn and garden engines use two ports per side, with the rear pair aimed rearward, giving the same result as having three ports at 90 from one another. Even more recent engines have a stratified air intake system using air passages in the piston and an additional carb barrel to provide air only. For model aircraft use it's probably not worth fooling with the extra weight and complexity.

As for Shindaiwa engines being too expensive, one can call around to the bigger landscaping businesses and see if they'll let go of the one they just ran over with their truck. Yes, it DOES happen! I'm a lawn and garden equipment mechanic, and I see it frequently.
Nov 29, 2012, 10:48 AM
Bellanca Kruesair
epoxyearl's Avatar
Got a brand new FS110 Stihl 4 stroke trimmer that way.The Amigos dropped it into an irrigation pond on the golf course,and the Superintendent threw it in the trash. Now I'm no flies a Great Planes Stearman just fine-not overly powerful,but adequate.
Latest blog entry: Rut-roh !
Nov 29, 2012, 11:32 AM
KV4PL, FAA 107 Certified
FloridaFlyBob's Avatar
Maybe I try slapping a Harley motor in my Hellcat, just not with a kickstart. lol

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