ST G 34

[Leester]

I have used this engine on a Ringmaster and it was super fast, just wondering if anyone has used it on a Cardinal or like sized plane  Since I have the quick change engine clamps on my ARF Cardinal I'm tempted to try it with say a 11-4 prop. It seems like it has the stones to fly it...maybe

[Bill Barber]

  Not being sarcastic , but try it and let us know ! I know some one who had one in a ARF Vector and had some problems with the motor . But if I remember correctly I think the problem was tank related .
Cheers , Bill

[Brett Buck]

I have used this engine on a Ringmaster and it was super fast, just wondering if anyone has used it on a Cardinal or like sized plane  Since I have the quick change engine clamps on my ARF Cardinal I'm tempted to try it with say a 11-4 prop. It seems like it has the stones to fly it...maybe

  Profile Cardinal - should be plenty, and an 11-4 sounds like a good starting point.

    Brett

[Bill Little]

Hi Lee,  I hope you get it figured out.  

Does any one know what Bob Gieseke's set up on this engine was?  I know he used it a while back.... 

Big Bear

[Leester]

OK, the next time I get a chance to go flying I'll give it a shot and let you know how it went.

[Balsa Butcher]

Hope it goes well. A friend has one on a Sig Primary Force ARF. The engine is a powerhouse but has a strong tendency to run away, even with a high launch RPM. Kind of an FP-40 run away on steroids. An 11X4 prop is what he uses also. I reluctantly put mine aside for a future carrier project but did I mention...tons of power!   

[Brett Buck]

Hope it goes well. A friend has one on a Sig Primary Force ARF. The engine is a powerhouse but has a strong tendency to run away, even with a high launch RPM. Kind of an FP-40 run away on steroids. An 11X4 prop is what he uses also. I reluctantly put mine aside for a future carrier project but did I mention...tons of power!   

       If I was going to develop the engine, this is what I would do -

   Start with an 11-4 or 11.5-4 APC and whatever muffler comes with it. Use 10% fuel.
   Start with about a .255 venturi with ST spraybar/needle, panty hose diffuser
   Set engine by peaking out lean on the ground, and then backing off just enough that you can hear it change. Or peaked out lean with the nose pointed up.  Forget 4-stroking, you want to set it just like an R/C guy.
   Fly, get lap time. In fact, just enough gas to run about 10 laps would be sufficient.
   It will probably be WAY too fast.
   Start reducing the venturi in .005 increments, repeat until the lap time comes out around 4.8-5.0 with the "peaked and back off " setting.
   Go back one .005 increment larger
   Then set the needle by lap time. The goal is to get the venturi small enough to permit a medium-strong 2 stroke throughout the flight, with a decent lap speed.
    Check the maneuvering performance - should be a medium 2 in level flight, then peaking out in the maneuvers. If it sags over the hill lean in the vertical 8, add .005 to the venturi diameter, back off the needle to get the same lap time, then try again.

      The venturi will wind up A LOT smaller than you might expect, because a St34 at full performance is *far* more than you can use on this airplane. The goal is to get the venturi small enough to reduce the peak power to something we can use. Once you are in the ball park of thr right size, it will take pretty small changes to tweak it for maneuver performance.  And all your stunt buddies will be concerned about you "burning up" the engine because it's running in a constant 2-stroke. Just like the same engine runs *1000's of times in R/C planes*. It will likely be irritating to listen to, it would burn up a Fox 35,  but it won't burn up an ST34.

     This is essentially the approach I used for the "small engine" experiments. Aside from the exhaust tuning effects on the 25FP, it pretty much worked the way you would expect. And it's pretty close to what PTG did for the Magnum 36.

     Brett

[Leester]

Thanks for the details Brett, the supplied venturi is .272 if I measured correctly. I'll have to check my stash and see if I have anything closer to the .255. I'll also give a weight on the profile Cardinal with engine, the stock muffler is huge, I'll see if I can balance with it or use something different.

[Steve Helmick]

Check around and see if the muffler bolt pattern is common to more mainstream R/C engines, like the OS LA & FP's. Gives lots of options, if that's a match. Some searching of the muffler ads in Tower, or MACS Products can also give the needed matching.  For example,  I'm running a stock OS .46LA muffler on my Magnum XLS .36...nice if you happen to need nose weight, which this airplane did, and it still needed 1/2 oz.    But whatever it takes, you've gotta get the CG right.

The ST G.34 might just be da bomb with a MACS Muffler. Prop it to launch at 10k+. Steve

[Robin_Holden]

Greetings fellas from S.W.France.

Just thought I'd give you my experience of the ST34 , of which I have three.

First things first , I found they need a lot of running in .......Usual 3 minute fast/rich runs with a small'ish prop' . Around an hour and a quarter , cooling down after each run.

I installed TWO head shims.
Best prop' I've found is my best friend , the APC 10.5 X 4.5.
Fuel is 5% Nitro , 22% lube , with around 7% being Castor.
I use a Tongue Muffler , available from Randy by the way. I opened out the holes a 'touch' as well.
Plastic R/C tank , no muffler pressure.

Flying , I usually set for launch at around 9,600. Around three and a quarter turns open on the needle.

I have always been a fan of Super tigre since I was a lad brought up in Northern England. I couldn't afford them in those good old days !
Oh .... My 34's always need a really good choke to get started and I've never needed an electric starter.

A nice little engine ,lovely quality , light and compact , but ...... And there's always a but ! I would choose a Magnum 36 [ sq. head ] or a  TT 36 every time as a much easier to set-up engine .

Just my two pennyworth ,

regards to all ,

Robin [ ex. pat. Brit in the Charente full of ex. pat. Brits ]

[Martin Quartim]

I suggest you try the engine Stock to see how it works first, it may work fine the way it is on a bigger model like the Cardinal. If it doesn't work right, then you will know where you are and which direction you'll need to go to make it better.

The stock venturi seems about right to me. I end up with .275 venturi on my Enya SS30  w/o muffler pressure. The higher rpm you work the larger venturi can be used. Keep in mind that using more fuel  means more lube and more cooling for the engine.

The Philly FP setup approach works amaizinly well on the OS FP, which is based on larger venturi, unrestricted muffler, reduced head compression, high rpm, low pitch prop. I have been using this aproach with great sucess on my Enya engines which are, like yours and the OS FPs, an R/C engine.

You can easyly restrict the stock venturi using an Air Filter from BruLine which has two elements, fine and coarse. I had one of my engines setup so that in very hot days I just remove the airfilter, in the very cold days I use the FINE element and in between the COARSE one.

Good luck

Martin

[Leester]

I took the Cardinal to the flying with the intensions of doing some testing, but during preflight my down line came off the B/C (factory crimp job) Oh well lucky thing it happened then, btw the Cardinal with the 34 came in at 49 3/4 oz's. The only other muffler that I had that would fit it was from an FP20-25. I was going to try that also. I'll have to cut into it now and wrap new lead outs then try again 

[Leester]

With new lead outs installed I got to fly it today. Stock venturi and NVA, Power Point 11-4 prop, Sig 10-20 fuel, Thunderbolt 115493 plug. I launched at 9900-10200 rpm and it was great, my flying buddy said it sounded a hair lean but that's what Brett said to run at. It was running 5-5.1 laps and had great line tension although I don't fly the pattern it was fine for what I do know. Four ounces of fuel lasted forever, 7 cranks on the fueler ran it for 5 1/2 min don't remember for sure but I think 10 filled it. I used the OS E-2030 muffler (no pressure). So for me it's fine and I'm going to keep using the G-34.

[Brett Buck]

With new lead outs installed I got to fly it today. Stock venturi and NVA, Power Point 11-4 prop, Sig 10-20 fuel, Thunderbolt 115493 plug. I launched at 9900-10200 rpm and it was great, my flying buddy said it sounded a hair lean but that's what Brett said to run at.

   By a little lean to you mean "2-stroking all the time" (good), or "sagging in the maneuvers" (bad)?  You still want it to pick up a little in the maneuvers, or at least not sag off.

   Brett

[Leester]

It was 2 stroking all the time, I didn't notice any sagging at all.

[Brett Buck]

It was 2 stroking all the time, I didn't notice any sagging at all.

   Sounds fine to me, then. A lot of stunt people (trained by years of Fox 35 experience) assume that 2-stroking = burn-down. These engines are designed to 2-stroke all the time, unless you go "over the top" it's not going to damage the engine.

      By the way, you sound like you might be pretty close to an *ideal* setup. If you back the needle off a little bit, there's a good chance that you will run slower, but get more "boost" in the maneuvers, so that even if you miss the setting you will still have enough poop in the maneuvers.

    Brett

[Martin Quartim]

Good to hear that the stock engine is working well for you. Now you can start testing a few things to make it even better.

As Robin wrote above, I also recommend you try an APC 10.5x4.5. It is known to be the magic prop for this size engine.

If in a hot day you feel your engine is not developing the power you want, don't be afraid to open up a bit your venturi, power is your friend, the more the better.  A venturi up to .285" should work well as long as you keep the rpms "high".

Your power will be good when you have line tension every where, if you get a bit slack line ohhh you could use more power 

Martin