Author Topic: SuperTigre G-51 anyone using them? (Read 4501 times)

Paul Taylor · « **on:** February 24, 2010, 07:16:47 PM »

I do not see a lot of chatter on these. Pros / Cons?

RandySmith · « **Reply #1 on:** February 24, 2010, 09:02:36 PM »

Quote from: Paul Taylor on February 24, 2010, 07:16:47 PM

I do not see a lot of chatter on these. Pros / Cons?

Hi Paul

I setup and sell a Lot of these . People like them they are a great buy..for the money.
I also make many parts for them ,muffler, NVAs, lite Tubes, venturies, I stock bearings and other parts, The other good thing is this motor is still being made by ST

Regards
Randy

Greg L Bahrman · « **Reply #2 on:** February 24, 2010, 10:03:04 PM »

I think it is a great motor......I love mine.......Started with a 12 x 5 Rev-Up......Switched to APC 12 1/4 x 3 3/4 and it works even better.

Paul Allen · « **Reply #3 on:** February 25, 2010, 02:25:42 AM »

I seconded what Greg said,motor works well on APC prop.
Paul Allen

Balsa Butcher · « **Reply #4 on:** February 25, 2010, 08:07:22 AM »

Great engine when properly set up for stunt. Difficult to get consistent runs with when stock. At least that is my experience.

Robin_Holden · « **Reply #5 on:** February 25, 2010, 08:37:25 AM »

Hi all from S.W.France........

Love my ST51 as it has been worked on by Mr. Tom Dixon ..... Brilliant ! Transformed !

Easy to set-up , reliable and and swings a Graupner 12x5 with quiet authority.

After reading the other posts I'll try the APC prop' as well.

Love my OS 46 LA as well which works great right out of the box with no mods. once run-in.

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

phil c · « **Reply #6 on:** February 25, 2010, 11:12:47 AM »

I've had a stock ST 51 in a couple of planes. The CL version does have lower timing, but it still is a higher rpm engine. Mine does better propped at 10,200 or better on the ground with a 3 blade MAS 10/5 or similar load.

Here is Mike Nelson's site for complete mods to one, almost as much work as building a new motor!
http://www.machineconcepts.co.uk/aeromodelling/st51/st51-1.htm

Air Ministry . · « **Reply #7 on:** February 25, 2010, 07:33:37 PM »

There not a ST .46 , and stock , if you lettem rev theyll 'switch ' in and out of the power band nicely ,
and also haul an awfull lot of aeroplane.

going to try an elbow feeding through into in fuse mouted 'silent muffler',as t runs well on it.

Merco 49 lost power on all other mufflers than this,its also good nose weight .
Many others remaks concerning the 'silent muffler' whowever are less than polite or kind .

Such as 'whats thad garbage can doing on the side off'

The reverberations are usefull for getting suburbanites to belive space ships are about, on still misty mornings . . .

Gene O'Keefe · « **Reply #8 on:** February 26, 2010, 07:52:04 AM »

I have 4 G-.51's (2 that Tom Lay did his magic on and 2 that Frank Bowman did his magic on) and am running only tube mufflers ( from Randy Smith and from Scott Dinger) and they all run GREAT ! I agree with Randy that they run better on tube muffkers than tongue.

Geno

Andrew Borgogna · « **Reply #9 on:** February 26, 2010, 11:17:04 AM »

I have been using one for three years, box stock and it works great.
Andy

Jim Pollock · « **Reply #10 on:** March 05, 2010, 05:12:09 PM »

Hmmmm,

I use a Bolly 3 blade on mine...Yeah I know, don't break any of the 3 I have. It is a Bolly 12X4.25 that was re-pitched to 5.0 and cut down a little to 11.75. The plane I use it in is a Shark .45 that weighed 58 Ounces new. Now it's about 59.5 I guess it needs a little de-oiling of it's finish. Looking forward to flying it again when Spring ever arrives here in the Anniston area!

Jim Pollock

RandySmith · « **Reply #11 on:** March 05, 2010, 07:07:43 PM »

Quote from: Jim Pollock on March 05, 2010, 05:12:09 PM

Hmmmm,

I use a Bolly 3 blade on mine...Yeah I know, don't break any of the 3 I have. It is a Bolly 12X4.25 that was re-pitched to 5.0 and cut down a little to 11.75. The plane I use it in is a Shark .45 that weighed 58 Ounces new. Now it's about 59.5 I guess it needs a little de-oiling of it's finish. Looking forward to flying it again when Spring ever arrives here in the Anniston area!

Jim Pollock

Those 3 blade CF props and many others are back in stock

Randy

James Mills · « **Reply #12 on:** March 13, 2010, 09:05:33 PM »

Quote from: Ty Marcucci on March 05, 2010, 07:44:44 PM

Hi Paul. I have them on four of my bigger planes. Great engine for Intermediate. If I evedr get to Advnaced, I will switch to PA's. All of mine have been done by T&L (Tom Lay). I have found if the ST .46 won't pull it, stick the .51 in. Beats building a new and lighter plane

Ty,

I've done okay with a 51 in my Shark in Adavanced, don't count it out.

James

Balsa Butcher · « **Reply #13 on:** March 13, 2010, 09:49:37 PM »

Ditto the above comment: ST-51 in a 46 sized Vector - potent combination.

Bill Little · « **Reply #14 on:** March 23, 2010, 10:41:31 PM »

I used my ST 51 in my first *BIG* plane, a 64 oz. SV 11. It flew it great on 12-5 wood props.

I used the same engine on my USA-1 at 54 oz, with a Bolly 3 bld 11 5/8-4.75. Ask Derek Barry about that combo.

One of the very best 4-2 motors I have had (other than the PAs).

Big Bear

Andrew Borgogna · « **Reply #15 on:** April 06, 2010, 11:06:40 AM »

I have some additional information on this topic. After returning from VSC I decided to rebuild my ST-51, crock pot treatment, new bearings and a new ring. I installed a set of Boca Bearings and had Frank Bowman setup the piston with a new ring. The new ring made a big difference, in fact if I was to purchase a new one I would have the ring swapped out from the git-go. The original ring was allowing a lot of blow by, the area below the ring was black just as Frank had predicted.

Don't know if the bearings made a difference, but I am sure they will last a long time and I had the engine apart. Make sure you have a torch ready for removing the bearings and the cylinder. Also a large vice is required to press the crank shaft out of the prop thrust bearing. One last thing, the ring is pinned if the ring gap is not centered on the pin it won't compress and allow the piston to enter the cylinder.

Anyway the engine runs better than new.

Jim Pollock · « **Reply #16 on:** April 24, 2010, 03:36:01 PM »

Andrew,

Just get one from Tom Lay, it already has the Bowman rings in it. Plus the best 4-2 run there is except for the
PA engines.

Jim Pollock

Randy Powell · « **Reply #17 on:** April 24, 2010, 08:14:54 PM »

Pat Johnston just switched over from Stalkers to the ST51. Box stock and he seems to like them.

Bill Little · « **Reply #18 on:** April 26, 2010, 11:07:07 AM »

Many years ago, (1993) Tom Lay told me he liked to rework the R/C version a little better. I have no clue as to what he does internally, but that one was an awesome engine! Like I said, it hauled the SV11 in the winds at Norfolk with no problem. I have never tried the APC
12 /14 X 3 3/4. Can anyone tell me how the engine run reacts to that prop? (if that made sense) A wet 2, or a 4-2? Never tached it with the Bolly 3 blade set at 4.75 in the USA-1, so I don't know what rpm I was turning. Just set it in a cackle....

Big Bear

Air Ministry . · « **Reply #19 on:** May 04, 2010, 02:07:48 AM »

I know what they SOUND like on a 10 x 4 three blade .

Like the cylinders ging to end up in the next paddock.

So I got a G-40 ring injun ,for that prop. As its the

same foot print / fit .Peaks at 15,000 or something.

Was an experiment to improve the performance of

a 71 Oz. Spitfire in20 Kt. Winds.Tho handles that

fine stock, powerwise .Dont choke it to much with

a tight tounge muffler if you want to utilise its output.

Said to be better than V-60 .Switches at high R.P.M.

'Switched' on the 10 x 4 !

Andrew Tinsley · « **Reply #20 on:** May 04, 2010, 10:26:12 AM »

Hello Everyone,
Have read this thread and a few others on the forum. I swore I wouldn't comment but...... I have a very low time Italian stunt G51, it has been carefully run in and everything looked fine. Like Pipemaker Mike, nothing I can do with it, will make it run correctly. Tried the usual, props, fuel glowplugs and oil. I even read Randy's words and music. No matter what I do, I can't get a stable run. Took it apart and found no sign of blow by around the ring. Checked tank and gave up on it. Put in a Merco 61 Lite case and evrything runs as it should.
OK, not asking for more possible solutions. Are the manufacturing tolerances that big, as to cause the huge differences, between "runs straight out of the box" to "won't run correctly no matter what I do to it". It isn't as though I don't know what I am doing! Hells bells I can even get FP40s running like pussy cats without any internal butchering and that is with the large OS venturi and plenty of power!
It is either very large manufacturing tolerances stacking up, or a lot of folk don't really know what an excellent stunt run is like. I am just curious and I don't mind if people call me for implying that a lot of folk are satisfied with less than perfect performance! Right, this is where I retire to the bunker!

Andrew

richardhfcl · « **Reply #21 on:** May 04, 2010, 11:55:15 AM »

Andrew,

I feel your pain: Of the three ST-51's I've purchased only one of them ran decently out of the box. The other two required
trips to after market engine-working specialists. I would suggest that S.T.'s are not manufactured like the O.S. engines which
all seem to run well "right out of the box."

Don't get me wrong, I really do like my S.T. 51's, but some of them might require an engine tuner to ge them to run
decently.

Good luck with yours,

Richard Ferrell

Martin Quartim · « **Reply #22 on:** May 04, 2010, 08:01:18 PM »

For what is worth, the Enya SS50 is a drop in replacement for the ST G51, same dimensions just the NVA position is different. The Enya SS50 is much lighter and runs stronger then a ST G51, contest proven several times down here box stock.

Martin

Bill Little · « **Reply #23 on:** May 04, 2010, 11:56:54 PM »

Quote

It is either very large manufacturing tolerances stacking up, or a lot of folk don't really know what an excellent stunt run is like. I am just curious and I don't mind if people call me for implying that a lot of folk are satisfied with less than perfect performance!

Hi Andrew,

Well, I can't say if the tolerances are that far off, etc.. All I can say is that *MINE* ran as good as a stunt engine can. Derek Barry who is on the USA World Team and has had a couple top five NATS finishes lately, flew the USA-1 with the ST .51 and was very impressed. Derek knows what a stunt runis supposed to be like. I also know what a real stunt run is supposed to be, and I know when I get it. I have had Randy Smith fly my models, and observe me at other times, to get the runs correct. If anyone knows how to do that, he does. No I know what the engine is supposed to react like, so it is much easier to get a really really good run, now, on my own.

Maybe the production change to China made a difference on the ST G51?? Windy was the first to really say anything about them back when they first came out in the early '90s. He did a lot with them, and really liked them, but that was also when pipes started coming on, so the ST G51 was moved to the rear.

Does my ST G.51s have as much power as my Aero Products PA 51? No...... But, the ST G51 will fly a lot of models really well, and a lot of people have used them with no problems. I know mine likes to launch around 9800 on a 4 1/2-4 3/4 pitch prop, 5% nitro (no more than 10% when it's around 100* and all castor oil. The oil part, I don't know why, but when I run 25% all castor (Tom Lay's instructions), it runs mcuh better.

Ship those no good ST 51s to me, I'll find a place to hide them for you!

Mongo

Andrew Tinsley · « **Reply #24 on:** May 05, 2010, 03:30:39 AM »

Hi Bill,
Thanks for the reply. So ST G51s can run straight out of the box and give a very good stunt run at that! So my surmise that people don't know what a really good stunt run looks like is incorrect and I am more than happy to accept that. So where is the problem? I have tried all the suggested run parameters here and on SSW and they do not work for me. So maybe I am the dumbo! I still can't get my head round the huge differences that people report. I always assumed that the Italian engines were better than the Chinese ones, maybe I am wrong on that assumption? Anyone know different? I just get unstable runs, thought it was cooling, so I tried running without cowl and investigated oil mixes from straight castor to straight synthetic, no differences.
The runs are peculiar, I can get a 4-2-4 most of the run with odd outbreaks of 2 after a maneuver lasting 10-15 seconds. Sometimes a good run and then the next one back to where I was. Occasional runaways and so it goes on. Its not tank, because when I put in the Merco the plane was as sweet as one could ever expect.
I have given up on the engine as the Merco is just superb. What bugs me is why the huge difference in reported performance? I don't want to go down Pipemaker Mike's route of a radical rebuild, anyway I don't get the same symptoms of burps on outside maneuvers, so I don't even think I have the same problems. What is different between a G51 that will and one that won't? Is it a mild runaway type situation? Same cause as the FP40, i.e. operating on the rising portion of the power curve. Looking at the revs we normally use, that seems to be a likely cause, but still why the difference?

Andrew.

Bill Little · « **Reply #25 on:** May 05, 2010, 10:16:52 AM »

Hi Andrew,

I wish I could say why the problems have occurred for you.

A thought: the *Italian made* R/C engine and the C/L engine DO have different sleeves with different timing. Maybe the Chinese ones don't? That could mean the timing is higher and a runaway/sporadic run would possibly come easier.

If the blowdown and other timing specs are correct and the fits are in spec, the engine *should* be capable of giving good runs.

Bill

Allan Perret · « **Reply #26 on:** May 05, 2010, 02:43:30 PM »

Quote from: Martin Quartim on May 04, 2010, 08:01:18 PM

For what is worth, the Enya SS50 is a drop in replacement for the ST G51, same dimensions just the NVA position is different. The Enya SS50 is much lighter and runs stronger then a ST G51, contest proven several times down here box stock.
Martin

If my memory serves me, the ST G51 was a light engine, something like 10.5 oz without muffler. How much lighter could the Enya be. The SS50 you are talking about, isn't it one of the older styles of construction ? I thought they were on the heavier side. Straighen me out if I'm wrong.. Its been a while since I used a G51. It did do a good job of pulling a 62 oz Magnum. Mine was reworked by Dixon..

Martin Quartim · « **Reply #27 on:** May 05, 2010, 06:51:32 PM »

Hi Allan,

The Enya SS50 in my scale weighs 286.5g and the ST G51 made in china 314g, about 1 Oz heavier.

They are very similar in construction, the Enya SS50 has aluminum piston with ring and 2BB.

At last weekend contest there were two Enya SS50. Verol with a 65Oz Score was 1st in what we call Mini Fai Category and a new guy in Expert, my friend Patrick Hudson, flying a Derringer did very well finishing 10th (18 in the contest) ahead many veterans in Expert.

Sure many have had great success with the ST G51, but lately many have been complaining about the ST G51. At last weekend contest two guys gave me their problematic ST G51 to get it reworked.

Enya SS50 is an easy drop in replacement for an ST G51. However, it likes low pitch prop and high rpms like a piped engine.

Martin

Bill Little · « **Reply #28 on:** May 05, 2010, 07:27:11 PM »

Hi Martin,

I run a *mini* high rpm/low pitch set up. Props are pitched under 5" and the 4-2 is a rather high rpm break.

I really don't know what to say!

Big Bear

Allan Perret · « **Reply #29 on:** May 05, 2010, 08:27:33 PM »

Quote from: Martin Quartim on May 05, 2010, 06:51:32 PM

Hi Allan,

The Enya SS50 in my scale weighs 286.5g and the ST G51 made in china 314g, about 1 Oz heavier.

They are very similar in construction, the Enya SS50 has aluminum piston with ring and 2BB.

At last weekend contest there were two Enya SS50. Verol with a 65Oz Score was 1st in what we call Mini Fai Category and a new guy in Expert, my friend Patrick Hudson, flying a Derringer did very well finishing 10th (18 in the contest) ahead many veterans in Expert.

Sure many have had great success with the ST G51, but lately many have been complaining about the ST G51. At last weekend contest two guys gave me their problematic ST G51 to get it reworked.

Enya SS50 is an easy drop in replacement for an ST G51. However, it likes low pitch prop and high rpms like a piped engine.

Martin

I located an old file where I had recorded some of my engine weights and I had a ST 51 (Italian) listed at 11.3 oz or about 320 gram. I was thinking it was 10.5 oz, guess my memory is not as good as I had remembered...

Martin Quartim · « **Reply #30 on:** May 05, 2010, 09:10:59 PM »

Hi Allan,

My scale is in sync with yours, the Italian ST G51 in mine scale is also 320g, the Chinese ones are bit lighter with 314g

Martin

Brian Hampton · « **Reply #31 on:** May 05, 2010, 11:04:24 PM »

Quote from: Bill Little on May 04, 2010, 11:56:54 PM

The oil part, I don't know why, but when I run 25% all castor (Tom Lay's instructions), it runs mcuh better.

That's exactly what I found with my G51. With 80/20 all castor it would break into a frenzied 2 stroke at the start of any manoeuvre and then take about 2 level laps to come back to a 4 stroke. I struggled with it for a month trying every possible combination of plugs/compression/venturis/props but nothing worked until one day I ran out of fuel so gave it one more flight for the day on some 75/25 all castor I had with me. Holy cow! What a difference! An absolutely perfect continuous 4 stroke the entire flight (my preferred engine run). This was after I'd brought the engine back to box stock standard with the aim of starting all over again.

On reflection the light dawned on me as to why the instant change. My particular G51 is extremely economical (about 3 ounces for 6 minutes) so oil flow was very low causing it to overheat when it was loaded in a manoeuvre.

Air Ministry . · « **Reply #32 on:** May 05, 2010, 11:39:06 PM »

O.K. Andrew , a G-51 going cheap .??

Theory is , somewhere , the build up in the loose backplate feeds iregular mixture at times .

Globules of fuel pulling through , at times . Mine did this a few days early on ,Id forgotten.

Weighed mine (italian ) at green grocers / post office ! 313 Grammes .

Ones C/L ones Supplied R/C , C/L liner fitted .

Pulled heads , intakes a month or so ago. to inspect / measure -timing.
wosnt sure if differing. BUT their (the two ) identical .

opening edge of cranks angled a degree or two. Held the thing up to a Lamp

at the rear.Protractor on crank. Pointer fed through lug / mounting holes and

zeroed to even on sleeve timing.

R/c with C/L sleeve identical figures to C/L stunt . std.

DONT go near the head bolts without a 'tool supply' alen key.No 2 dollar shop ones !

Well used ones got T stain on piston crown, others started to form.

Usually run 50 /50 Castor / Syn. sometimes 20 C, 3 Syn.Sometimes theres only 'wots left',

So im thinking the 'wierdo' runs were on full Synthetic (cool power ). MAYBE IT ?

Syn and Castor have very differant properties.

Ran a litre and a half of castor ,no nitro fuel in winter on bench before I flew em in a

1450 G. plane for that again , before hammering em. (running em hard ).

ST plugs lasted foreever , those fireballs crunched 3rd flight . sometimes Enya 3s. o.k.

If youve seen a Commado simmering , with the insides of the exhaust white one shade short of molten ,
youd see some machines operate rather well leaned out and 'warm ' (actually close to 'heat soak'. ) .
KNorton was on a run thru Desert road (high Alt) at above 'down't bypass' speeds continuous. @ 70 m.p.g.

So , after two hours relaxed runnig to 'bed in ' , puttem to work.

For needle setting , I go up into fully lean ,(two stroke ?) , then back it out till its fallen just out of that 'note'.
Coming up from rich id found sometimes inconsitante.

Be a while before the G-40 gets 'the treatment.' . Will let you know if its a dog.

Andrew Tinsley · « **Reply #33 on:** May 06, 2010, 03:35:04 AM »

Thanks everyone,
I started off with 25% oil as this seemed to be one of the keys to getting this critter running, so I don't think that is my problem. I have checked the backplate and all seems to be well. I have installed a new gasket with a little RTV silicone and will give the engine one more chance! As I said before, mine is an Italian G51 and it definitely has the CL timed sleeve. At least I have found from Bill's post that you can get an excellent stunt run from these engines, I really was beginning to believe that most people put up with a less than perfect run!
I have had a fair experience with FP 40s and their known problems. I have a machine shop and tried sleeve mods. You can get those engines to do a fantastic 4-2-4 but very low on power going this route. Eventually went the Philly flyers route but with the large OS venturi so as not to sacrifice power. Interesting exercise and very successful. I am blowed if I am going this route with the G51. There must be something amiss with my particular engine, but checking it out thoroughly, I can't see anything wrong. To summarise, I have used different fuels (oil content), glow plugs (found Enya No3 the best), venturi sizes, props and running high pitch lower revs and low pitch higher revs. The high pitch lower revs gives the problems already listed. The low pitch high revs is the better set up, but I still get similar results but not so obvious as you would expect. Its not tank and yes I do use a filter and no I don't have leaks or crud in the NVA.
I like to think that I know what I am about (but quite willing to find that maybe I am not that good!). Pipemaker Mike went to a lot of trouble modifying his engine. I don't want to go that route as there appears to be many people that get them going more or less stock. Bill can you give me your setup, fuel, plug, prop and NVA details. It would be good to start at a known good set up and take it from there. Maybe I will give my ST51 one last try!

Bill Little · « **Reply #34 on:** May 06, 2010, 02:40:06 PM »

Hi Andrew,

Fuel: Sig 5% nitro/25% all castor w/Randy Smith's Snake Oil added
Plug: Fireball hot
Prop: 12-5 Rev Up Govt. Surplus wood on 64 oz SV-11; 11 1/2-4.5 3 blade (flat back) Eather CF on 54 oz. USA-1

Launch rpm: (??) giessing abut 9800, it was in a *cackle* on the ground.

I also have a T&L G.51 and used the same basic set ups.

Bill

Bob Reeves · « **Reply #35 on:** May 06, 2010, 06:23:59 PM »

Andrew, you are not alone. I have a China ST 51 with a Bowman ring in a Skylark that has been giving me fits for 3 years.. It refuses to run with a tube muffler, I mean it will simply quit sometimes on the take off roll. Last year at Brodaks I was trying every combination I could conger up running Power Master 10-22. Finally a friend loaned me some 10-20 fuel mostly synthetic he mixed himself. It ran better on this fuel than it ever has.

Haven't flown it since Brodaks and have some Fox 10-20 all synthetic I'll try and see if I can duplicate what I was getting at Brodaks. Everyone has said run a tube muffler and 10-22 50/50 but mine flat will not run with that setup.

Air Ministry . · « **Reply #36 on:** May 06, 2010, 08:59:55 PM »

Other 'roumer' is they dont NEED a lot of oil . 20 % max, once run in .maybe 18 % after a few (3?) hrs running.

Had 6;30 on 80 c.c. of 80/20 fuel in the 72 Oz. plank Spitfire.

Australian users have said " add a head gasket for Nitro " 5 - 10 % , or two for 10 % up .

Certainly preigniteing on the 10 x 4 , - Detonating . 2 flights. Still fine, a tough motor .

Presumably supplied for F.A.I. fuel , no nitro . ( try the silent muffler )

Also , the old 'oversize vent pipe ' trick . ? ?

The 1/16 bore plumbers copper tubes fine .and no good at all for feed ,will dry of under load .
A 1 in. piece to cap a std large bore vent can improve it. Stops big pressure variations in
tank from fuel surge & intake (tank ) velocity.used Muffler pressure,and still watch this .

Best props the two 11x5 Zinger 4 blade I contrived .
Steady 4 on 12 x 6 Tornado .
used a master 12x6 wood and got nowhere .

The 3 blades ran a big 3 in Goldberg plastic (yuk) spinner .
Ran good with the FLYWHEEL effect . tho if you dont open prongs
at rear itll spit the nose off occasionaly ,and often on engine stopping .