Author Topic: tigre46 set up (Read 7020 times)

Chris Belcher · « **on:** December 15, 2015, 03:03:15 PM »

I just got my first ever ST46 on ebay. New BOCA bearings and a new Bowman ring. Ordered a sprinkler venturi, NV and tongue muffler from RSM. I know this is old hat for most but i always wanted a ST46 and just now got around to buying one. Any help on set up would be appreciated.

Dave_Trible · « **Reply #1 on:** December 15, 2015, 03:27:58 PM »

Chris it's a good motor. I ran them for years past their hay day. The best advice is DON'T tinker with it- just run it. It's an older style engine that runs best in a four-two-four setting with 6- pitch props. I always preferred the RevUp 11.5-6 wood prop. You'll scorch it trying to run it two-stroke and low pith props. That's for modern screamers. Use plenty of oil. It's working weight limit is around 54 ounces. It starts running out of steam carrying any more weight.

Dave

Air Ministry . · « **Reply #2 on:** December 15, 2015, 10:09:02 PM »

A lot of people use the MERCO muffler , which come up here & there occasionally .
Compact , light , & the Bolt spacing mates, though 6BA or English thread .

dunno if constraining mufflers arnt why rings chew out , but seems likely . Should start a Debate on this topic , on Injuns Page ? .

Brett Buck · « **Reply #3 on:** December 15, 2015, 11:47:30 PM »

Quote from: Chris Belcher on December 15, 2015, 03:03:15 PM

I just got my first ever ST46 on ebay. New BOCA bearings and a new Bowman ring. Ordered a sprinkler venturi, NV and tongue muffler from RSM. I know this is old hat for most but i always wanted a ST46 and just now got around to buying one. Any help on set up would be appreciated.

>OK, Let me know what your ST 46 set up
>is. Fuel, prop, venturi size, etc.
>Thanks!

From a post on SSW about 15 years ago...

BOX-STOCK ST G21/46 -do not "fix" head, do not add head gaskets (replace with stock gasket if it begins acting funny as gasket compresses), do not replace bearings unless rusted, do not look for "porkchop" crank, do not replace with trick conrod, etc. "Red Box" version with full muffler lugs preferred (only because they had, usually, good rings).

Standard "long" venturi bored to .173
10 or 15% SIG
K&B R/C plug.
SST Tongue muffler with 16 3/32 holes
Rev-up 12-6 Pro II or Special Pro III, greatly thinned with 5.75" basic pitch, increasing to 6.2 over the last 1" (good overall)

OR

Rev-Up 13-5 cut to 12", greatly thinned, with 4.9 helical (windy weather).

Uniflow with NO PRESSURE

proparc · « **Reply #4 on:** December 16, 2015, 08:57:11 PM »

Quote from: Chris Belcher on December 15, 2015, 03:03:15 PM

I know this is old hat for most but i always wanted a ST46 and just now got around to buying one.

If there is one motor you should have just for having it,(not competition etc) the ST46 is one heck of a good choice!! Can it go up against a heavily modified Saito 72-NO. Can it hang with a Moki 150-no. But, IMHO it is sweeter then ALL of them.

Brett Buck · « **Reply #5 on:** December 16, 2015, 09:09:06 PM »

Quote from: Matt Spencer on December 15, 2015, 10:09:02 PM

A lot of people use the MERCO muffler , which come up here & there occasionally .
Compact , light , & the Bolt spacing mates, though 6BA or English thread .

This muffler was the one used by Peter Deane on his Fox 40, and it had the effect of distributing oil in every possible direction!

Brett

Chris Belcher · « **Reply #6 on:** December 17, 2015, 08:07:09 AM »

Is the tongue muffler from RSM Ok to use? I see in an earlier post where a certain number of a certain size hole was recommended. I suppose i will learn a lot when i bench run it this weekend, as far as back pressure and so forth...

Brett Buck · « **Reply #7 on:** December 17, 2015, 10:01:06 AM »

Quote from: Chris Belcher on December 17, 2015, 08:07:09 AM

Is the tongue muffler from RSM Ok to use? I see in an earlier post where a certain number of a certain size hole was recommended. I suppose i will learn a lot when i bench run it this weekend, as far as back pressure and so forth...

I don't know, I haven't seen one. Start with 16 3/32 holes, threaded for 4-40x1/8 screws, and fill up 4 of the holes with screws. Fly it, and if you want to speed up the break recovery, remove a screw at a time. If you want to slow down the break recovery, add one screw at a time. This may change during the day, so you have to keep up with it. Don't go under 8 open holes. You can adjust the overall power this way too, so if you only want to alter the response times, you might also want to change the nitro a bit to compensate, add or remove glow plug gaskets, or maybe go to props with more or less pitch at the tips - which also feeds back into the break response, too.

There are many complex and hard-to-explain interactions between the various pieces, so extensive experimentation with each particular setup is required. That's why I don't look back fondly to the days of 4-2 break engines, even though I had a great one. Now I take my airplane out of the car, gas it up, flip the prop, and fly it and rarely even think about it.

Brett

Air Ministry . · « **Reply #8 on:** December 17, 2015, 06:06:21 PM »

Chris Belcher · « **Reply #9 on:** December 17, 2015, 07:57:03 PM »

whats the difference between a g21 40 and g21 46? Same case? The stamped "46" looks funny on mine....like it has been ..I don't know...double punched. the 4 looks right but the 6 is funny looking....hmmmm

Massimo Rimoldi · « **Reply #10 on:** December 18, 2015, 12:58:29 AM »

I'm sure you do not reveal a secret if I say that
both engines have different versions, but basically the fastest way to check if it is a .40 or .46
(without considering the inscription on crankcase of course) is to measure the diameter of the piston.

G21 / 40 Bore: 20.4 mm (about 0.8031 inch)
G21 / 46 Bore: 22.0 mm (about 0.8661 inch)

Massimo.

RandySmith · « **Reply #11 on:** December 18, 2015, 10:56:27 AM »

Quote from: Chris Belcher on December 17, 2015, 07:57:03 PM

whats the difference between a g21 40 and g21 46? Same case? The stamped "46" looks funny on mine....like it has been ..I don't know...double punched. the 4 looks right but the 6 is funny looking....hmmmm

They use most all the same parts crank ,venturie, rod, NVA, Bearings, wp screw, backplate
The different parts in the 40 are: head, case, sleeve, piston, W pin, ring (or rings) and gasket set,

Randy

Chris Belcher · « **Reply #12 on:** December 18, 2015, 01:29:18 PM »

Randy,
Do you have any of your CNC tubes for this? I got one for my Enya SS40 from you and they are great!

RandySmith · « **Reply #13 on:** December 18, 2015, 03:43:18 PM »

Quote from: Chris Belcher on December 18, 2015, 01:29:18 PM

Randy,
Do you have any of your CNC tubes for this? I got one for my Enya SS40 from you and they are great!

Hi Chris sorry I am out of the ST size ones

Randy

Walter Hicks · « **Reply #14 on:** December 18, 2015, 05:02:46 PM »

Randy, If the G21- 40 and 46 case are similar except for the bore can a ST 46 piston and liner be put in the G21 40 case by boring out the case
so the liner will fit. I have brand new G 21 40 and Brand new Piston, ring, and Liner for 46 ? Thanks for your time.

RandySmith · « **Reply #15 on:** December 18, 2015, 06:14:39 PM »

Quote from: Walter Hicks on December 18, 2015, 05:02:46 PM

Randy, If the G21- 40 and 46 case are similar except for the bore can a ST 46 piston and liner be put in the G21 40 case by boring out the case
so the liner will fit. I have brand new G 21 40 and Brand new Piston, ring, and Liner for 46 ? Thanks for your time.

Hi Walter

It has been done before, I have done many of them, however there is a problem, the bolt holes at the top of the case on the 40, is a smaller diameter than the 46 bolt hole spacing, so what you have to do, is file 6 notches in the top lip of the 46 sleeve, this is needed to clear the 46 lip on top of the sleeve, WARNING if you just try to screw the bolts in, they will go, but they will hit the side of the 46 sleeve and can distort the sleeve, and mess up other parts.
It is easier if you find one of the older thin 46 sleeves, and use a new 40 case with side luggs, but you need to pay close attention to the clearance of the bolts

Randy

Walter Hicks · « **Reply #16 on:** December 18, 2015, 06:45:02 PM »

Randy thanks for the response .

Air Ministry . · « **Reply #17 on:** December 18, 2015, 07:48:44 PM »

Chris , If you look at the under piston / end Ex. Ports , at T.d.C. if theres sub piston induction there (little openings from crank clearance radius )
it is a .40 ; The 46 does not have any opening from under the piston to the outer exhaust ports with the piston at the top of the stroke .

Walter , we did a 40 case .46 to replace a radio control landinged intake split .46 , used a new muffler lug 40 case .
Decide the dwepth of the cylinder cut afore ye go , so as to do it in one sweep , not further later .

Used a mauled .46 head as a ' chamber / button , with a .40 head machined to accept the .46 ' button ' . Naughty ! .

I have a spare mauled .46 head , used as nosegear on tarmac Id Think .

Chris Belcher · « **Reply #18 on:** December 19, 2015, 11:35:25 AM »

Bore measured 2mm....it's a 46.

Chris Belcher · « **Reply #19 on:** December 19, 2015, 07:18:12 PM »

make that 22mm, it was actually 21.995

Chris Wilson · « **Reply #20 on:** December 19, 2015, 11:27:19 PM »

Quote from: Matt Spencer on December 17, 2015, 06:06:21 PM

Yep, good ole Reg Towell - Tigre 46 and Merco muffler.

Since these mufflers are longitudinally split you can very easily add are a restricting thimble to the exhaust outlet and vary the ID to tailor for back pressure.

And if the halves do not have a perfect join to them and leak oil you can always lap the contact edges.

Chris Belcher · « **Reply #21 on:** December 30, 2015, 10:50:46 AM »

Ty,
Turns out this was a 40 bored out and rebuilt to a 46. The guy that sold it to me was unaware as was i until i noticed the stamp on the case was funny...looked like someone had punched a 6 over the 0 and the head bolts measured to a 40 size. He was EXTREMELY supportive and helpful and the motor actually runs really well after i created some clearance for the head bolts not to hit the lip of the liner. I felt bad for the guy that sold it but agian he was very supportive...glad we have guys like that in this hobby.

frank mccune · « **Reply #22 on:** September 12, 2016, 02:59:34 PM »

Hi Chris:

I would suggest to do NOTHING to your new ST .46! I have seen some that were STOCK perform and they were perfect stunt engines. As you gain more time with it, you may wish to experiment with it. For now, just enjoy a great engine.

Best of luck,

Frank McCune

proparc · « **Reply #23 on:** September 14, 2016, 07:49:38 AM »

Got my first ST 46 when I was 14 year old. My first REALLY good stunt motor. Still have it, still runs perfect. The secret to ST 46's, is to do nothing to them. Break them in, fly them and don't crash them,(not good for them).

P.S. Prior to my first ST 46, my Enya 35 5224 was doing a bang up job for me. This is the motor that really got me in the CL stunt game. But, the ST 46 was on a whole nother level.

P.S. I guess I should have said, unless your the great Randy Smith. Sooo, the proper wording should be, leave it stock or send it to Randy Smith.
My S.T. 60's are all Randy Smith by the way. Stock S.T. 60's can't touch them.

RandySmith · « **Reply #24 on:** September 15, 2016, 11:45:29 PM »

actually NO they are not best stock, even though they will run well stock, most times, I have done over 600 ST 46 B&B engines. There was late model ones that had full circle cranks, many had the aluminum band come off of the counterweight,, if that happens they can destroy your engine , The older T-Crank was better than the full circle one. They are in better balance with no chance of killing your engine
They are also many that the rear bearing came apart
They are ALL the stock ones I have seen leak out of the front raw unsealed bearing...some leak more than others
So better rear bearing and sealed front ones are better than stock
The engines full circle cranks, cut into more of a T- crank results in a better balanced smoother running engine
The engines are better with True venturies sized at .165 to 1.75 are better than the stock venturie that has a full circle cut all the way around, This results in most all of them burping on and off at the end of the run when fuel is low, and that large space in the venturie fills with air and fuel mixed. Plus the Stock size of .157 in the venturie hole is OK for a smaller airplane, but is NOT optimum .
There was at least 4 different heads , All work OK, but, the last version squish band high CR , is the best one, most times with 1 thick stock head shim. I cut a heat dam around the glow plug in the B&B ones I have done, that makes them run cleaner and 4/2 cleaner, and is more tolerant of cool plugs or plugs going bad .
The first series long rods , not the short one is the best rod to use for stunt and a better balanced better smoother engine.

There is more that will help make the ST-46 a better engine, we can talk about those later

Randy