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HelicopterGasser Model RC HelicoptersOther › Building one of my own and I need some help...
09-01-2009 02:32 AM  8 years agoPost 1
Machinehead01

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Lower Michigan

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50 size, going to swing 620's to 640's. Not using your standard Zenoa,using a Toro, because it fits between the frames better. The engine is a 26cc and runs in the high 12,000 rpm range(unloaded). I am thinking that it won't be near this high once placed under load. I need to know what gear ratio would work best for overall power and a headspeed in the 1900 to 1950 range. What I have so far is a 16 tooth pinion and an 87 tooth main. I can change pinions easily and go up a 20 tooth. Which should I start with?

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-01-2009 03:29 AM  8 years agoPost 2
Fixit

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UK

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Is this the one?

I only like to fly gassed up

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09-01-2009 03:56 AM  8 years agoPost 3
rilandtg

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Waldorf, MD USA

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Welcome machinehead!! Good luck with your conversion!!!!!! Have not done one this small but you are in good hands with Fixit and the rest of the guys!!!! Subscribed!

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09-01-2009 04:47 AM  8 years agoPost 4
Machinehead01

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Lower Michigan

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No, its this one.

Here is a pic of the engine.

The balance of this engine is excellent as Toro does engines for the long haul yard service. They are very ergonomicly designed for less hand vibration.

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-01-2009 04:53 AM  8 years agoPost 5
turboomni

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East of the Equator

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The balance of this engine is excellent as Toro does engines for the long haul yard service. They are very ergonomicly designed for less hand vibration.
AT what rpms??

Setup is everything, All my heli's can fly far better than I can pilot them

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09-01-2009 11:35 AM  8 years agoPost 6
copperclad

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NY

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I need to know what gear ratio would work best for overall power and a headspeed in the 1900 to 1950 range. What I have so far is a 16 tooth pinion and an 87 tooth main.
Hi Machinehead01

divide 87 by 16 to get your ratio 87 / 16 = 5.43

your gear ratio is 5.43 to 1 or 5.43 / 1

all we're saying here is that the pinion will do 5.43 full turns for every full turn of the main gear

so if you wanted a headspeed of 1900 , you multiply that headspeed by your gear ratio to get the needed engine RPM

1900 * 5.43 = 10317 , so if the engine could turn at 10.3 K with a 5.43 gear ratio , you would have 1900 RPM headspeed

hope this helps , cheers

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09-01-2009 02:18 PM  8 years agoPost 7
Machinehead01

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Lower Michigan

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turboomni

The top end I listed is with stock Makuni slide style carb, and stock muffler. Once the shaft and head of the weedeater was removed the engine smoothed right out, extremly low vibes though out the RPM range. Lots of weedeaters that you can buy today have the dual string setup, this is done not only to speed up cutting, but to balance the machine as well so that the vibrations are also lowered.
The Toro is very smooth even with a single string head. I'm not a big of the Zenoa as I feel that there are better quality,balanced engines out there, if you want to mod one for the application.
I guess what I should have asked is what gear ratio range seems to be the most common. Where in the rpm scale do most of the gassers run?

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-01-2009 02:44 PM  8 years agoPost 8
turboomni

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East of the Equator

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Sounds like a very interesting motor. Has it been used in a helicopter before? As a relative newbie to gasser's may I ask if the cooling fins large enough to cool the motor with a regular heli cooling fan? The fins look abit like the old G23 Zenoah with the corners of the fins missing. As far as gear ratio's I am not the one to ask as the experts here will chime in. I will tell you my X-Cell 1005 gasser runs a 6.43 to 1 ratio and my Spectra is a 7.07/1. This is with 700 sized blades though. Good luck with your project!!

Setup is everything, All my heli's can fly far better than I can pilot them

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09-01-2009 09:04 PM  8 years agoPost 9
copperclad

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NY

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I guess what I should have asked is what gear ratio range seems to be the most common
Hi

LOL , yes , carefully framing the question can save everyone time , cheers

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09-02-2009 04:21 AM  8 years agoPost 10
Machinehead01

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Lower Michigan

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Not to my knowledge...

Turboomni. I have never seen this engine used in a gasser before. I went looking for different carbs today as the slide style has a very stiff spring and would work a servo quite extensively. I'm also trying to find a carb that has a bigger bore so that the high end will be alittle more forgiving. I am planning on altering an Outrage pipe for a YS91SR for the exhaust. It's about the same sizing on the ports and the outlet is bigger so I'm thinking it may work without having to mod it much. Plus someone will have to look close to see that she ain't nitro.

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-02-2009 12:18 PM  8 years agoPost 11
copperclad

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NY

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I'm also trying to find a carb
http://www.partsforscooters.com/Carburetors

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09-02-2009 05:53 PM  8 years agoPost 12
AceBird

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Utica, NY USA

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9-1-09
The engine is a 26cc and runs in the high 12,000 rpm range(unloaded). I am thinking that it won't be near this high once placed under load.
I would suspect that you will need to change the carb in order to get anything out of it for heli application. Just a hunch.

9-2-09
I have never seen this engine used in a gasser before.
One of the issues of building your own is you have no other data to compare to for performance. You will have to play around to get the engine to perform the best it can and develop the speed torque curved. The numbers from a Zenoah, or modified engine will mean nothing if you can’t get the engine to perform like said.

The carb is the first modification. Without the increased bore it will be useless for a heli. Once you put that gas guzzler on then you will start to see the vibes of the Zenoah. If you look at what others have done to the Zenoah’s internals you should prepare yourself for several attempts. Once you remove the metal it is not so easy to put it back.

Good luck with your experimentation.

Ace
What could be more fun?

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09-06-2009 11:29 PM  8 years agoPost 13
Machinehead01

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Lower Michigan

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I have moved this thread...

I originally started this thread in the Audacity forum so i have thus started reposting back on the original thread If your interested in following it, it's under the thread, Really BIG Block!!! Pantera Gasser.

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-06-2009 11:35 PM  8 years agoPost 14
Fixit

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UK

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09-07-2009 12:01 AM  8 years agoPost 15
Machinehead01

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Lower Michigan

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Thanks Fixit..

Although I can machine just about anything I want I still struggle with computers on a regular basis, my idea of a reboot is to kick the thing across the room when it's giving me problems.

Thomas

"You judge according to the flesh; I am not judging anyone."

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09-07-2009 12:25 AM  8 years agoPost 16
Fixit

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UK

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I kicked mine and it spit the link out

I only like to fly gassed up

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