Another ST G-51 question

I know the answer may vary from set up to set up but how much fuel does a ST 51 burn per pattern?

Thanks

Mine needs from 135cc to 145cc, depending on ambient air temperature.

Mine burns about 5.3 ounces. Therefore, I have to have a 5.5 ounce tank. I still fill it up and don't go overtime.

Jim Pollock:D

On the T&L 51, I use a 6 oz. tank and pull out 1/2 to 3/4 oz. I use the 6 oz. in case I need to go to 10% or more nitro, but never really have had to.
So I am in the same ballpark as Jim.
Bill <><

B Little. Sure glad for your response. My Brodak Legacy with the T&L ST-51 is set up with the Sullivan 6 oz round clunk tank. I was also concerned about tank size. Not yet quite finished, but it weighs 51 oz ready to fly except I want to spray a couple of clear coats. That should come in at about 53 oz.

53 ounces???

WOW, how did you get it that light Floyd??? Inquiring minds would like to know! Most I have heard of are coming in around 60-64 ounces.

Jim. The LEGACY question is easy. First, I tossed out half of the kit wood and used my own wood from Riley Wooten. Second, I made the turtledeck from 2 pieces of 1/32" molded on a form. Third, the internal construction is too heavy, so I changed many of the pieces to lighter and thinner wood. Fer instance, no ply fuselage doublers: I used CF and epoxy instead of ply.

The LEGACY (now called LARCENY because of the mods) should come in a about 53 oz. with some clear coats (not yet applied--I'm waiing until the rain stops to do more spray painting).

I got a tube muffler from Tommie Lay which weighs 0.75 oz. Nice piece of work indeed!

The downside? If it ever hits the ground, it will become a cloud of balsa scraps... but I don't intend to hit the ground.

Standard Disclaimer:
Caution use at your own risk, results may vary, I am not a professional. I need to rely on smart people for their idea's, I don't have any of my own.

My G-51 was mounted in my Sig Magnum. Yep, you better get a 6 ounce tank. No matter if you using a 12/5, 12/6 or 13/5 prop, a six ounce tank will fly the pattern with ease.

Mike Clark
(MikeC)

Hi Rick
I have three SV12's - one with an ST51, one with a Stalker 51 and another with a Retro 60. The ST51 has the most poke and uses the least fuel. The high venturi lends itself well to the use of plastic clunk tanks and I have just a 4oz tank in. I have to take out about 15cc from that 4 oz tank. The fuel is 5%nitro, 20% first pressing castor and 75%methanol. Plug is an Enya No 3. I have replaced the heavy (5oz) muffler with one from a Merco 35 (just elongate the holes in the stub)Into this I use a silcon exhaust deflector to further reduce outlet size of the muffler. This has stopped the run away experienced by so many ST51 users. The motor is not modified in any way.
Hope this info helps.
Jim

> I know the answer may vary from set up to set up but how
>much fuel does a ST 51 burn per pattern?
>
>I used a six ounce Sullivan plastic tank with mine. No problems.
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> Thanks
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> Rick Henry

I use a full 6 ounce tank in my magnum. Get about a 6:35 flight on typical 80 degree day.

I find almost a one ounce variation as a function of venturi size. I am running .295 these days. I have a half dozen venturis from .285 to .307 that will fit.

2nd biggest contributor is the prop. Slow the engine and run a 12-6 with bigger break and you will use more fuel than with a higher rpm and a 12-5 or 12-4.

Nitro affects it also. I used 5% nitro most of the time with 22% oil (11/11) .

If you're trying to predict the size of tank to install in a model, just go with the standard 6-ounce unit and figure out a way to meter fuel when you've got a settled combination with which to work. I find the mustard-pump fueling devices to be good enough, as they deliver almost exactly 1 ounce per stroke.

And Jerry nailed it: Your fuel consumption, especially with an ST 51, can vary quite a lot depend upon venturi size to a great extent, some other variables to a lesser extent.

BUT, if you get all these variables lined up on the thirsty side of the equation, even six ounces might see you just squeaking by the 6:00 minute mark. That's plenty of time, of course, although it doesn't leave many laps for screwing around.

I have setup Over 150 of the ST 51s, I have found that they normally burn an average of 5 1\2 ounces.
I had one years back in a SIG Magnum, I used a Bolly 12.5 x 5.5, 12 x6 , and a 12 x 6.5n 3 blade I always got by with a 5 3\4 ounce tank.
Unless your running the engine very rich or using high nitro you are safe with a tank of this size.
I think the BYO 12 x 6 would be a good prop for this engine also
( the ones I had were really about 5.5 pitch)

My ST .51 just loved the 3 Blade 12-5.25 Bolly cut down to 11.5. Vertical performance was unbelieveable with that prop compared to a 12-5 or 12-6 Rev-Up Pro prop.