ST G21/46 questions

Hello guys,

I just picked up a ST G21/46 at a swap meet. It's an R/C motor. It's ringed, with the best compression I've ever seen in a ringed motor. Baffled piston. This motor says "chromed" on one mounting lug edge, and "A A" on the other. Did these motors come chromed from the factory or is that an addition afterward, and does anyone know the significance of the "A A"?

I saw on *bay, a couple months ago, someone was auctioning sets of four venturis for this motor, but those auctions are gone now. Does anyone know who this person is and how to contact him or her?

Roger, the gent and his pet Raccoon live in Little Rock, AR I believe. I have a set of his venturis and they are not up to stunt standards. Too small. Try Leonard our host.

The guy in Little Rock is Terry Rollings and can be reached at [email protected] Interesting comments on his venturi's are available all over this forum. Some pro some not. I bought a few sets for my ST 60's and some for the ST 46. Mine run fine for what I do and that may be the difference in opinion. I do know that they fit perfectly. For $25 bucks for the set of 4 it is a small investment. If you are not happy with them you can use them for ammo in your slingshot.

Brett recomends a .173, what sizes are Terry's?

Sorry, I can't remember the sizes. Email him and ask. He is a very good person and will get back to you quickly. All of his venturi's are made on a CNC machine and that is why they are a precision fit.

>Hello guys,
>
>I just picked up a ST G21/46 at a swap meet. It's an R/C
>motor. It's ringed, with the best compression I've ever
>seen in a ringed motor. Baffled piston. This motor says
>"chromed" on one mounting lug edge, and "A A" on the other.
>Did these motors come chromed from the factory or is that an
>addition afterward, and does anyone know the significance of
>the "A A"?
>

I have no idea about the A A. The engines were chromed at the factory, at least the models from the early 60's on.

Sounds like a nice engine, since it has the one and only thing that really makes a difference - a good ring. Get a nice .173 sprinkler venturi, SIG 10% fuel, and some Rev-Up 12-6's and you have a really good vintage stunt motor.

Brett

Thanks, guys. I'll test it at the field tomorrow (with the carb wired open) to see if it'll be worth the investment.

Actually it's not worth the investment. So just send it to me, then I'll have 8 of them. Ha ha No, really, send it to me. Please.

>Hello guys,
>
>I just picked up a ST G21/46 at a swap meet. It's an R/C
>motor. It's ringed, with the best compression I've ever
>seen in a ringed motor. Baffled piston. This motor says
>"chromed" on one mounting lug edge, and "A A" on the other.
>Did these motors come chromed from the factory or is that an
>addition afterward, and does anyone know the significance of
>the "A A"?
>
>I saw on *bay, a couple months ago, someone was auctioning
>sets of four venturis for this motor, but those auctions are
>gone now. Does anyone know who this person is and how to
>contact him or her?

ROGER......E-MAIL SENT
Scott(HO HO HO)Riese

Roger,
Do exactly as Brett says and you will be happy with the ST46. He helped me and mine works great.

>Roger,
>Do exactly as Brett says and you will be happy with the
>ST46. He helped me and mine works great.

I appreciate the thanks. Mr. Garofali had a lot more to do with it, however!

Considering Rev-Up 12-6's are now made of unobtainium what modern prop would be a good substitute? What 3 blade?

>What modern prop would be a good substitute?
>What 3 blade?

I asked Tom Lay that exact question.

His answer:
----

11x 5 1/2, 3-blade sq.tip., non-undercambered is good for the .46.
They are $45 +5 for box, and priority shipping.
Tom

[email protected]

----

Cy

>Considering Rev-Up 12-6's are now made of unobtainium what
>modern prop would be a good substitute? What 3 blade?

Are they? I haven't tried to get any for a long time. I know they are no longer manufactured, but there are sure a lot of them around.

At any rate, I had pretty good results towards the end of the era with a Bolly 12-6, and 11 1/4-6 1/14 Bolly 3-blade.

LAST EDITED ON Dec-14-03 AT 02:01 PM (CST)
 
Roger,

If you check this link regularly, you may find what you need.

http://cgi6.ebay.com/ws/eBayISAPI.dll?MfcISAPICommand=ViewListedItems&userid=tlrascal&include=0&since=7&sort=3&rows=0

Paul

Edit: Oops!! I see that you already found it.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=34056&item=3164640122

Yes, I did, thanks! I ran the motor today with the carb wired open and it runs fine. Used some Sig 5% nitro / 25% castor fuel I picked up at the same swap meet. The oil coming out the exhaust was pretty clear so I think the motor is broken in. Looks like we're pretty much in business with this motor. Now, for a plane...

>Yes, I did, thanks! I ran the motor today with the carb
>wired open and it runs fine. Used some Sig 5% nitro / 25%
>castor fuel I picked up at the same swap meet.

That's not going to permanently hurt anything, but i will run better and retain compression better with a 50/50 castor/synthetic blend. Straight castor will make the ring stick in the groove after a while. If this happens, it can usually be recovered by running it on synthetic blends for a while.

Yeah? Ok, thanks Brett. Definitely don't want to mess up the ring. I have some other fuel here that has half castor and half synthetic.

>Yeah? Ok, thanks Brett. Definitely don't want to mess up
>the ring. I have some other fuel here that has half castor
>and half synthetic.

To give credit where credit is due, the late Ed Southwick tipped me off to this. I had been running straight castor, switched and got a lot more reliable runs as a result.

LAST EDITED ON Dec-14-03 AT 05:56 PM (CST)
 
HI Roger

Most all of these motors were NOT chromed..as with the ST 60 the case has Chromed molded in , but most of the ones that were chromed ,
where the very early ones with thin sleeves and no side lugs.
They were ,and are very good stunt engines, chromed or not.

As far as the AA goes. most all of the part numbers back in the 60s started with AA I have several ST 46s that have AA 29 molded in. This s engine came from the same basic casting as the ST 29.. as did the ST G 21 35 and ST G 21 40 There are 5 different casting of the ST 46 case that I know of.
4 different pistons , 6 different rods
3 different rings, etc.... The motor changed much over the years

This one is chromed, I took off the head and looked. In fact, I can see cross-hatch marks in the chrome on the whole cylinder except the very upper-most area, where the chrome is real shiny. Funny thing, though, it has two head shims. Well, I put both of 'em back in and it runs okay.

At least I think it does. I put this old 10-6 Top Flite plastic prop on it and ran it on the 5% Sig fuel and it ran up to 11300 rpm. I didn't have a bigger prop to see if it could sustain that under more load. What should I expect from this motor anyway, with say a 12-6 like Brett recommends?

LAST EDITED ON Dec-14-03 AT 06:33 PM (CST)
 
>Most all of these motors were NOT chromed.

I had 6-7, of varying vintages from "red box", to the last production run, and they were all chromed, near as I could tell. It's pretty unmistakable - bright and shiny, between hone marks. I might have been lucky, but they were all the later model with muffler lugs and at least interchangable (if not identical) parts, and the long venturi. I thought the originals had thick liners, but I never had one to compare.

There were a truly mind-boggling number of "detail" variations in these engines over the years. They all tended to work, but I never saw any two that were completely the same.

HI Brett

You have special engines , hundreds of those were built here (in the US) by using parts, maybe they did use chrome liners in yours.

None of the last few production runs were chromed but the metal used was very shiney and may have looked like chromed.
I have had thousands of ST engines here ,among them was several hundered ST 46 s , and if you look at the two side by side you can see the difference, It is very hard to tell just looking at one ,the chromed ones also had much less honing marks.
The old ones all used thin sleeves, they went to the thicker sleeves in later runs. this is the main reason they got heavier.
The lightest ones were the ones that had
"SATURNO " and "B 29 \ 8" Molded into the case.
Most all of these had thin sleeves, some had single and some had double rings. The double ring versions used the short 35 rod.
I still have many thousands of Old Super Tigre parts here, and it is interesting how much they changed.
All of the ST 60s had Chromed molded into the case on them right up to point they stopped making them, and even though they used a very bright chrome looking metal, none of the last few runs of them were chromed either

Regards

>
>HI Brett
>
>You have special engines , hundreds of those were built here
>(in the US) by using parts, maybe they did use chrome
>liners in yours.

I doubt I got lucky, just not in my nature. I'll defer. I will say that the later ones that I got were generally not nearly as good as the earlier ones, and the rings wore out in remarkably short order, and never had good compression. The best engine I had, by far, was a "red box" with a single ring, and the short muffler lugs. I have no idea whether it's the "porkchop", fulll circle, or stuffer crank, or any of the other of the dizzying variations, since I had learned by that point to just leave them alone unless something was obviously wrong. Never had to do the "brake cylinder hone deglazing trick" on this one.