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Engine basics => Engine set up tips => Topic started by: Gary Anderson on September 26, 2007, 11:26:18 AM
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Hi guys, I pulled one of my old st 35's out and installed it on a old shoestring plane. I don't remember, will this engine 4-2-4? I started the old baby up and she seemed to just run a hard 2. When I supplied power to the glow plug she would 4-2-4, so I tried different glow plugs, all hot plugs. Maybe I just have to change tank setup, I don't think that would change it. She's not wore out, got good compression and looks brand new. Anyway I would appreciate any input. Getting lazy, though about pulling her out and install her on bench and try different tanks, needle valves, garbage can. The last remark is what the wife thinks I should do with all my junk, Ha Ha. Gary
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Hi guys, I pulled one of my old st 35's out and installed it on a old shoestring plane. I don't remember, will this engine 4-2-4? I started the old baby up and she seemed to just run a hard 2. When I supplied power to the glow plug she would 4-2-4, so I tried different glow plugs, all hot plugs. Maybe I just have to change tank setup, I don't think that would change it. She's not wore out, got good compression and looks brand new. Anyway I would appreciate any input. Getting lazy, though about pulling her out and install her on bench and try different tanks, needle valves, garbage can. The last remark is what the wife thinks I should do with all my junk, Ha Ha. Gary
Hi Gary,
AFAIK, the ST G35 (ball bearing) doesn't like to 4-2.
I have had the plain bearing ones, there are two of them. A flat top (2 cycle all the way) and a baffle piston one (4-2).
I guess the BB 35 *CAN* 4-2, but I don't know what it takes to make it do it! LOL!!
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Hi Gary,
AFAIK, the ST G35 (ball bearing) doesn't like to 4-2.
I have had the plain bearing ones, there are two of them. A flat top (2 cycle all the way) and a baffle piston one (4-2).
I guess the BB 35 *CAN* 4-2, but I don't know what it takes to make it do it! LOL!!
Hi Bill, I pulled her out of the plane, installed on test bench. You're right she doesn't like to four cycle. I ended up with a enya #3 glow plug (hot plug) clunk tank, for test. Bottom end stayed nice and cool using 10/22 with extra Castor. She just wants to cry, tried to make her four cycle all she would do is load up and quit. It seems to run a wet two cycle, oh well install ear plugs and hear what you want to hear, Ha Ha. Thank you Bill, Gary
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Hi..Was talking with someone and they mentioned a " Non-stock single bubble 2 part head " that was on a G-21 .35 ST...I havent a clue what he was talking about and not sure he was...can someone explain....
Thanks in advance...
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A Brodak 40 would be a good cure for a ST 35 S?P
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Fox S.35 would be a way better cure for a brodak .40 as well...... H^^
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I played with a flat piston dual ball bearing ST .35 and it seemed to want to behave like a combat engine - maybe that's what it was intended to be.
BUT, if you look back at one of Bob Baron's designs, the PA-6 as I recall, you'll see that engine turning an 11-4 prop at one constant speed.
Interesting article from a very smart man - possibly the forerunner of the tuned pipe theory???
I have been told by a number of people that the baffle piston plain bearing ST .35 is one of the best for the classic style of running.
Bob Z.
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Hi..Was talking with someone and they mentioned a " Non-stock single bubble 2 part head " that was on a G-21 .35 ST...I havent a clue what he was talking about and not sure he was...can someone explain....
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Joe, I see that you are in the houston TX area. Get with richard Stubblefield and he can easily explain what the head you are talking about. Those types of heads were used quite extensively by the combat guys. (Even I had some).
They are very similar to the current "two piece" head and head button used by the Fox Schneurle ported engines. We made a "clamp ring from the stock heas (metal lathe work) and then made a head button to fit inside the clamp ring The bubble is merely the combustion chamber in the head. Single bubble is one that is more or less a simple cavity of a given diameter from the squish band surface to the bottom of the plug. As opposed to a double bubble which has TWO separate shapes -- a larger "bubble which goes about half way down to the plug surface from the squish band surface and the rest of the way to the plug is a smaller diameter bubble.
confused enough? Check with Richard and he can probably show you one.
Bigiron
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I played with a flat piston dual ball bearing ST .35 and it seemed to want to behave like a combat engine - maybe that's what it was intended to be.
BUT, if you look back at one of Bob Baron's designs, the PA-6 as I recall, you'll see that engine turning an 11-4 prop at one constant speed.
Interesting article from a very smart man - possibly the forerunner of the tuned pipe theory???
I have been told by a number of people that the baffle piston plain bearing ST .35 is one of the best for the classic style of running.
Bob Z.
Hi Bob,
I wonder if Mr. Baron took his lead from the 1964 World Champion?? Juri Sirotkin used a 10-4 running fairly fast. ;D
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Hi Marvin....Back in Dinosaurs Age...the 70's...I used to fly at Melrose Park...Richard Stubblefield was flying there at that time..combat and really fast sport type planes...I doubt if he would remember me , but at least then...I always got a friendly "Hi Joe" from him..nice guy and I guess he has been doing this all along...There was another younger guy that flew combat at that time there...can't remember his name though....seems like he was most of the time out there with his dad...Dad was his pit crew and a dang good one...remember when that mean Fox 36 X made its arrival!..... ..They all had them along with the Tigres...damn..I miss my youth....grin
Happy Turkey Day everyone....
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Hi..Was talking with someone and they mentioned a " Non-stock single bubble 2 part head " that was on a G-21 .35 ST...I havent a clue what he was talking about and not sure he was...can someone explain....
Thanks in advance...
That was a motor that I had on ebay , that I am just about to go to the post office to mail. One of the rework techniques developed in the 70's was to machine he combustion chamber out of the stock head to make the head into a clamp. Then a new head "Button" is made to fit the liner and the head clamp. It is much easier to machine a head button than it is to machine a whole head. No mill work is involved. Just machine one side, flip it over in the lathe , machine the other side and you are done. Jett manufacturing does their head assemblies this way. The particular motor that i had was and ex Russ Green combat motor from the 70's. The head button looked like it had a little less compression that stock. Possibly so it would be easier on plugs. Back then we were using about 40-50 percent nitro in combat motors. I did not realize that that motor had a button type head until I cleaned it up for sale.
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Example of a button head for stunt.
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Ok..thanks for all that info....Really..
Anyone have any experience with G-21 .40 ? I think this may be a ringed piston engine...I am thinking it is not the same as the older G-21 .35 engines previously discussed...but then I may be wrong....
Any help appreciated..thx in advance.