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  • August 11, 2022, 06:04:54 AM

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Author Topic: SH37 Development  (Read 1310 times)

Offline fred krueger

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SH37 Development
« on: June 08, 2022, 06:13:40 AM »
Electric power is currently dominating model aviation.  However, there are still those among us who still favor IC as a viable power source.  Unfortunately, the number of manufacturers has almost vanished for 'sport' engines.  There are still producers of 'completion' engines, but these are quite expensive and a bit prohibitive for most of us.  For control-line fliers this is even more true.  In an attempt to find a useful engine for the '35-40' size of CL models, I acquired a SH .37 from MikeGoesFlying.com.  This link goes to a playlist of short videos detailing development of this engine for CL stunt.  Hope you find it useful.
Fred

https://www.youtube.com/playlist?list=PLCpE_gezDmE3s9oxbPf8Iwhw5GuLJZBuq


Offline Motorman

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Re: SH37 Development
« Reply #1 on: June 08, 2022, 12:26:38 PM »
Does it have more power than a Brodak 40?

Offline fred krueger

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Re: SH37 Development
« Reply #2 on: June 08, 2022, 02:13:15 PM »
I don't know.  I recently acquired a NOB Brodak 40 at an estate sale.  I have not run it.  All I can compare it to is a Magnum .36.  It appears to have at least as much power as that.

Offline Dennis Toth

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Re: SH37 Development
« Reply #3 on: June 08, 2022, 04:14:04 PM »
Fred,
Who manufactures the SH 37 engine? Who is a seller in the US? Looks like a nice engine what is the weight with and without the muffler?

Best,    DennisT

Offline fred krueger

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Re: SH37 Development
« Reply #4 on: June 08, 2022, 05:03:20 PM »
Dennis,
SH engines are made in Taiwan.  Here's the spec page from the US importer:
https://www.mikegoesflying.com/shop/airplane-engines/glow-engines/sh-37-aircraft-engine/
They are a bit heavier than a Magnum .36 so I used a tongue muffler to attain the same CG.
Fred

Offline Motorman

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Re: SH37 Development
« Reply #5 on: June 08, 2022, 06:51:54 PM »
Wasn't there somebody who was reworking these or making piston/liners for them with stunt timing? They seem to have a massive heat sink in the head. Maybe for RC use with higher nitro?

Motorman 8)

Offline fred krueger

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Re: SH37 Development
« Reply #6 on: June 08, 2022, 07:38:24 PM »
I was trying to provide a 'reasonable cost' option for folks who don't wish to spend over $300 for a stunt engine.  If you add after market piston/cylinder sets, now the price is easily over $200.  Yes the engine has a larger square head.  I could machine some material off the crankcase and head using my Taig lathe but that's extra work.  The whole point of this exercise was to provide a working 'stunt' engine with minimal effort and cost.
Check out the flying videos and see if you think it works.
Fred

Offline Motorman

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Re: SH37 Development
« Reply #7 on: June 08, 2022, 08:47:40 PM »
Right, I guess that's why they never went through with it or, maybe it was the Evo 36, don't remember.

Anyway, seems to run good on a CL stunt ship.

Motorman 8)

Offline Dennis Toth

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Re: SH37 Development
« Reply #8 on: June 09, 2022, 07:48:47 AM »
Fred,
Interesting, on the web site it also shows a SH GF6 6cc .37 Gas Engine that uses a special turbo glow plug to run on 91 Octane gasoline and oil. It is the same price and just about the same weight as the straight glow version but since it uses gasoline will only need half the amount of fuel saving about 2 - 2 1/2 oz. That might be something worth looking into. I would think the way to run this is in a 2-2-2 high rpm/low pitch the way they run the OS FP/LA's.

Best,   DennisT

Offline fred krueger

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Re: SH37 Development
« Reply #9 on: June 09, 2022, 08:06:41 AM »
Dennis,

With the current cost of glow fuel, that certainly sounds interesting.  One more experiment for someone.  I probably won't spend any more $ on this myself, but I am curious how this would run in a stunt application.
BTW, I mix my own glow and diesel fuel.

Fred

Offline Brian Gardner

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Re: SH37 Development
« Reply #10 on: June 10, 2022, 05:01:44 PM »
I have a project running on this - but way way behind schedule on it.

Wasn't there somebody who was reworking these or making piston/liners for them with stunt timing? They seem to have a massive heat sink in the head. Maybe for RC use with higher nitro?

Motorman 8)

Offline Dennis Toth

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Re: SH37 Development
« Reply #11 on: June 10, 2022, 06:12:11 PM »
Fred,
I think it would run just fine for current stunt thinking on high rpm/low pitch setup. I wonder if just changing the head (likely needs more compression) and venturi (smaller gas is like diesel half the amount of fuel) plug would allow the glow version to run the gasoline?

Best,   DennisT

Offline Motorman

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Re: SH37 Development
« Reply #12 on: June 10, 2022, 06:17:43 PM »
on the web site it also shows a SH GF6 6cc .37 Gas Engine that uses a special turbo glow plug to run on 91 Octane gasoline and oil.

Won't that put it down about 30% on power from the alky/nitro version? If it would pull a Sig Banshee it might be worth trying. Might just be an extra heavy Ringmaster engine. On one of the reviews said it had the same power as a 25 alky motor in combat flying.

Motorman 8)
« Last Edit: June 10, 2022, 06:37:31 PM by Motorman »

Offline Brett Buck

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Re: SH37 Development
« Reply #13 on: June 11, 2022, 05:50:04 PM »
Wasn't there somebody who was reworking these or making piston/liners for them with stunt timing?

   What would you change about it? All the current good stunt engines (with the exception of the Retros) are RC engines with venturis and no other changes.

     Brett

Offline Brett Buck

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Re: SH37 Development
« Reply #14 on: June 11, 2022, 06:11:09 PM »
Electric power is currently dominating model aviation.  However, there are still those among us who still favor IC as a viable power source.  Unfortunately, the number of manufacturers has almost vanished for 'sport' engines.  There are still producers of 'completion' engines, but these are quite expensive and a bit prohibitive for most of us.  For control-line fliers this is even more true.  In an attempt to find a useful engine for the '35-40' size of CL models, I acquired a SH .37 from MikeGoesFlying.com.  This link goes to a playlist of short videos detailing development of this engine for CL stunt.  Hope you find it useful.
Fred

   This is a really good idea and it looks like you are getting somewhere. The only question/concern I have is that a modern 37 should be pretty powerful, and might be tough to handle on the smaller "35-sized" airplanes. If you can get it tamed down enough with limited modifcations, that would be great.

     Brett

Offline Dan McEntee

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Re: SH37 Development
« Reply #15 on: June 12, 2022, 07:16:17 AM »
  I don't understand why they make these engines so heavy with all the detailed cast in ribbing and such?? Why the huge head on these things? I was reading about the new OS .35 AX (I think it was) a few years ago and was surprised OS came out with a new engine in that size. Trouble was that you just could not find them! I think Randy Smith offered them set up for control line at the time and the engine was considered the heir apparent to the Aerotiger .36 I think. I found a used one on eBay pretty reasonable so I picked it up to see how it ran. It was easy to set up as the same venturi arrangement that I had for my OS.32s fit right on. I decided to test it on my original SIG Primary Force that was gaining weight and tipped the scales at close to 50 ounces now and dropped right in where the OS.32 was. Man, that thing was a beast!! I tried all the usual tricks of the trade to tame it down and tried all sorts of prop combinations, but eventually went back to my tried and true OS.32 and put the .35 away. My first impressions on the SH.37 would be that this is similar. The model Fred is flying it on in his videos if a Top Flite Tutor -II and most guys fly these with a LA.46 or ST.51 in the nose. Looked like it was doing a credible job to me in the videos.
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   Dan McEntee
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Offline Motorman

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Re: SH37 Development
« Reply #16 on: June 12, 2022, 09:10:34 AM »
   What would you change about it? All the current good stunt engines (with the exception of the Retros) are RC engines with venturis and no other changes.

     Brett

I don't I not the one who's doing it. I would guess lower exhaust timing?

Motorman 8)

Offline fred krueger

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Re: SH37 Development
« Reply #17 on: June 12, 2022, 06:41:44 PM »
Dan,

I think you've seen this plane at the 'Ice-O-Lated' in St. Louis.  It is my own scratch-built creation.  It is a 51" wing-span extended fuse version of a Tutor.  I guess you could call it a 'tweener'.
I suppose I could do some rework on the engine like I did on my Evolutions, but I was trying to come up with something useful at minimal cost and effort.  Basically, I added a head shim, due to the extra oil over most RC use, and cut a venturi within Claus Maikis recommended range for the displacement, then ran it in a relatively high rpm (10K-11K) with a lower pitch prop.

Fred

Offline Martin Quartim

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Re: SH37 Development
« Reply #18 on: June 13, 2022, 07:42:01 PM »
The performance in the video is very very good! Well done and thx for sharing.

How heavy is it w/o muffler?

Martin


Old Enya's never die, they just run stronger!

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Offline Steve Helmick

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Re: SH37 Development
« Reply #19 on: July 06, 2022, 05:20:09 PM »
Why all the fins and gussets on the crankcase? I'd say they're for style (that "weedeater" look) and to survive the usual R/C sport bod crashes. Pretty silly. Most those guys try it, crash it, and go away.

It's likely that these engines were designed by the same guy that designed engines for OS, Magnum, Tower, etc. Did you notice the suggested nitro content? Crazy or some sort of translation problem?  :o Steve
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Dave Hull

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Re: SH37 Development
« Reply #20 on: July 07, 2022, 02:15:44 AM »
The "style" of the engine, with square-ish case and head is similar to the older OS engines. It is a lot like the OS CV series. Probably a lot of car and some heli lineage designed in. The square case provides material for the bypasses. Note how the exhaust port in the sleeve isn't really centered on the side of the engine, it is back at more of a 45 degree position. And once you have a square case you might as well put a square head on it.

I don't really see an issue with the extra webs and gussets. It is a very good thing to have a case that is dimensionally stable. Sort of the opposite of the Fox .35 Stunt....

And, having bounced more than a few control line engines off the pavement, I can say that it isn't just "R/C noobs" that do it. I most recently bounced a Nagmum Bloohead during a "takeoff situation" in a scale racing plane. The head was mangled and the plane was headed for some major surgery, but the engine still runs fine. The case survived and is still racing...gussets, webs and all.

Dave

PS--I think the nitro levels quoted in the engine spec sheet is pretty typical for heli engines. Lots of power to weight, right?  But I suspect the .37 would run fine on 5-10% with no changes. I'll have to go back and see if Fred stated what he was using. (ok, he said he was running 5/22)


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