Author Topic: Starting point for ST 51 (Read 2435 times)

Matt Brown · « **on:** August 16, 2018, 06:31:58 AM »

I have acquired a used, RC ST .51 to go in my Sig Magnum. I was planning to order a new set of bearings and a new ring from the guy that took over Bowman Rings if he has them. Since it is RC, I’ll need a venturi and NVA. I have several Aero Products NVAs in stock but no venturis. Not sure whether this engine takes the sprinkler style or conventional with the spray bar across the venturi. I assume I’ll need some head shims to set the compression to whatever it needs to be. Beyond that, I don’t know what else it will need.
Can someone lead me in the right direction for setting up this engine? I’ll need a prop or two as well. I’m guessing something around a 12x5 or maybe a 12.5x5?

Thanks, Matt

PS, I’m not opposed to sending it to someone to have it set up either.

James Holford · « **Reply #1 on:** August 16, 2018, 08:32:53 AM »

Following this. I also have a r/c ST.51 i need to convert.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Dane Martin · « **Reply #2 on:** August 16, 2018, 08:54:29 AM »

Ugh I'm not at home. I don't remember what size venturi, but I had Jim Lee make one, and a ST NVA goes through the case. I also have one that the NVA goes through the venturi. That is my battle proven one. It's been flying that way since 1992 I believe. I can get that info, but I'm sure there's folks that'll respond that know a lot more than i. I just copied the known good ones.

Robin_Holden · « **Reply #3 on:** August 16, 2018, 01:47:32 PM »

I bought one of the last ST 51 engines years ago , but the C/L version. I have no experience of the R / C version.

Expected it to behave . It didn’t. Wouldn’t hold a setting . It was horrible.
The solution ? It went to Mr Dixon , who worked his magic.

It came back a transformation. It purrs , just like a proper Tiger.
With an MAS or Graupner 12x5 prop’ and Enya No 3 it is brilliant.

Fuel with at least 20% lube , half and half and at least 5%nitro’.
Perfect on the front of my profile Cardinal.

Dan McEntee · « **Reply #4 on:** August 16, 2018, 05:56:49 PM »

Be advised that the R/C version is NOT the same as the C/L version. The difference is in the timing of the cylinder liner. All else will interchange. Randy Smith can make it usable, and Tom Lay had a few customers that preferred the R/C version. I have been running them stock out of the box since 1994 with much success in everything from my Shark.45s to a 72 ounce Magnum. SIG Champion 10% and Glow Devil R/C long plug. They do not like a lot of pitch in stock form, and the APC 12.25 -3.75 is a good prop to start with. I have recently started to try an APC 12-5 sport prop that is a narrow blade pointy thing and shows promise. Some have been using the Thunder Tiger 12.5-5 or something like that. So a search on here and you should find lots of info, as it has been discussed almost as much as FP-40 and LA.46 set ups. I didn't have much like for a tongue muffler and use Scott Dinger or Randy Smith tube type mufflers for good exhaust flow. Probably one of the best power to weight ratio engines since the ST.60.
Type at you later,
Dan McEntee

Chris Fretz · « **Reply #5 on:** August 16, 2018, 07:34:23 PM »

Quote from: Dan McEntee on August 16, 2018, 05:56:49 PM

Be advised that the R/C version is NOT the same as the C/L version. The difference is in the timing of the cylinder liner. All else will interchange. Randy Smith can make it usable, and Tom Lay had a few customers that preferred the R/C version. I have been running them stock out of the box since 1994 with much success in everything from my Shark.45s to a 72 ounce Magnum. SIG Champion 10% and Glow Devil R/C long plug. They do not like a lot of pitch in stock form, and the APC 12.25 -3.75 is a good prop to start with. I have recently started to try an APC 12-5 sport prop that is a narrow blade pointy thing and shows promise. Some have been using the Thunder Tiger 12.5-5 or something like that. So a search on here and you should find lots of info, as it has been discussed almost as much as FP-40 and LA.46 set ups. I didn't have much like for a tongue muffler and use Scott Dinger or Randy Smith tube type mufflers for good exhaust flow. Probably one of the best power to weight ratio engines since the ST.60.
Type at you later,
Dan McEntee

Do you use any of the R/C versions converted to control line? If so how much of a difference is there? Or have you only been using the control line version since 94?

Thanks
Chris

Dan McEntee · « **Reply #6 on:** August 17, 2018, 04:08:49 PM »

Quote from: Chris Fretz / Formerly known as #Liner on August 16, 2018, 07:34:23 PM

Do you use any of the R/C versions converted to control line? If so how much of a difference is there? Or have you only been using the control line version since 94?

Thanks
Chris

All of mine have been c/L versions. Some times I have to really to pinch myself to remind me how long ago that was! I have several stashed away and have really only used three, two stock and one T&L, and all are still on the original ring and run well. You can check the parts listing that comes with each engine and see the different part numbers for the cylinder liners. Tom Lay told me that the R/C versions would really run away if used stock. He did change something in them for the customers that preferred them but I don't know what. Randy Smith has posted before that he can deal with the R/C versions. You can try and line up one of the Brian Gardner ABC P/L sets and be all set to go by just adding a venturi, OEM stock one or an after market.
Off to Paducah!
Dan McEntee

Matt Brown · « **Reply #7 on:** August 17, 2018, 04:19:08 PM »

I just got my ST 51 out of storage. FWIW, it is an Italian made version per the case casting. I thought it had a carb on it but it has a homemade looking venturi and ST NVA. I had ordered bearings but looking it over, I doubt I will need them or a ring for that matter. It has the ugly ST muffler, the one with the short round pipe that bolts to the exhaust face and the the muffler itself clamps on the OD of the short stack. I had already bought a tongue muffler for it though.
Anyone know how much Randy Smith charges to make it a real CLPA engine?

Thanks, Matt

Air Ministry . · « **Reply #8 on:** August 18, 2018, 08:04:52 PM »

The thought crossed my mind , the R.C. one might be better on the 10 x 4 three blade tornado , for ' the wind '.
As the C.L. version sounds like its going to blow the top of the engine , with one .

You get a distinct ' switch ' 2-4-2 with the C. L. , but at around the 5 in pitch / rpm bit .

R.C. version peaks out at 16.000 , not the C. L. versions 11.000 , acording to ' the book ' .

What Pitch are people running on the R C Version ??

Steve Helmick · « **Reply #9 on:** August 20, 2018, 12:09:54 PM »

Quote from: Robin_Holden on August 16, 2018, 01:47:32 PM

I bought one of the last ST 51 engines years ago , but the C/L version. I have no experience of the R / C version.

Expected it to behave . It didn’t. Wouldn’t hold a setting . It was horrible.
The solution ? It went to Mr Dixon , who worked his magic.

It came back a transformation. It purrs , just like a proper Tiger.
With an MAS or Graupner 12x5 prop’ and Enya No 3 it is brilliant.

Fuel with at least 20% lube , half and half and at least 5%nitro’.
Perfect on the front of my profile Cardinal.

The problem here is the ring fit. I'm not a fan of ringed engines, but know that if the end gap is non-existent, you'll have a disagreeable engine, and if there is too much end gap, you'll have a weak engine that burns lots of fuel. I like both the 12-5 and 12.25 x 3.75 APC's on my G.51. Different run, both pretty nice. I've also tried the 12.5 x 5 TT Cyclone, but it seemed like maybe too much load for my engine. I like 10-22 and a Randy Aero CNC tube muffler.

Steve

dale gleason · « **Reply #10 on:** August 27, 2018, 08:59:29 PM »

I've not run my ST51 since that low pullout at a VSC years ago left me with a shaft run, prop blades cut clean of. Before that time, that motor ran as great as a motor can. Never any troubles at all, probably 6 years of use. I lowered the spraybar from the venturi down to the case which required some drilling that I was able to eyeball and drill with a drill press.

It was in a Skylark with a metal tank and the spraybar was exactly in line with the tank feed tube, a half inch above the motor mount rails. I used Powermaster 11/11 and 10% nitro, except at Albuquerque raised the nitro to 15%. I used a tongue muffler.

The prop was the RevUp 12x5 that was available on the internet...a military drone prop, I was told. I think they show up on ebay periodically.

It is not an RC motor, and I'm not sure if it is Chinese or Italian. It's hard to tell, some boxes say Italy and the motor says China, and vice versa. It has been a jewel and I hope yours does the same.

dale g

Chris Fretz · « **Reply #11 on:** August 28, 2018, 03:24:57 AM »

Quote from: dale gleason on August 27, 2018, 08:59:29 PM

It is not an RC motor, and I'm not sure if it is Chinese or Italian. It's hard to tell, some boxes say Italy and the motor says China, and vice versa. It has been a jewel and I hope yours does the same.

dale g

If it is Italian it will say made in Italy on the side of the case. If it's Chinese it will say China on the backplate.

Air Ministry . · « **Reply #12 on:** August 28, 2018, 06:35:08 PM »

Quote from: Chris Fretz / Formerly known as #Liner on August 28, 2018, 03:24:57 AM

If it is Italian it will say made in Italy on the side of the case. If it's Chinese it will say China on the backplate.

ACTUALLY . If its ASIAN it will have a FOUR DIDGIT Number STAMPED on the Lug Side .
SOME have ' made in Italy , still. On them . AND the stamping . Assembled Or Early Asian ones . ! from Italian made parts ? maybe ??

SOME have ' CHINA ' Inside the Backplate . or outside the inner face of backplate , if your being awkward .

IF its STAMED 4 didgit / Number Here on lug below exhaust . Its NOT Italian Built , I should think .

just found a picture of a ' ALDRICH ' one , so thought Id put it on too , For 51 appreciasts .

Steve Helmick · « **Reply #13 on:** September 01, 2018, 05:37:47 PM »

Interesting that the GMA engine has 6 holes in the mounting lugs. One of mine is that way, from Dirty Dan. He did it so it would bolt in place of a Royal .45. A Magnum/ASP .53 or XLS .46/.52 will bolt into the same model.

Steve

frank mccune · « **Reply #14 on:** September 12, 2018, 08:23:47 AM »

Hi Mat:

My friend has the same engine and I have a G .49 Sport only one BB, that were originally RC engines, We Had them converted to CL by making an intake and adding a ST type of NVA. Both engines could not be any better!!!!! Convert it and enjoy.

Good luck,

Frank McCune

Balsa Butcher · « **Reply #15 on:** September 12, 2018, 02:46:55 PM »

I drilled one of mine out like shown on the Aldrich engine. It was to get it to fit into an overweight plane that was originally powered by a ST-46. If done carefully it looks clean. Swap was a success.

Author Topic: Starting point for ST 51 (Read 2435 times)

Matt Brown

Starting point for ST 51

James Holford

Re: Starting point for ST 51

Dane Martin

Re: Starting point for ST 51

Robin_Holden

Re: Starting point for ST 51

Dan McEntee

Re: Starting point for ST 51

Chris Fretz

Re: Starting point for ST 51

Dan McEntee

Re: Starting point for ST 51

Matt Brown

Re: Starting point for ST 51

Air Ministry .

Re: Starting point for ST 51

Steve Helmick

Re: Starting point for ST 51

dale gleason

Re: Starting point for ST 51

Chris Fretz

Re: Starting point for ST 51

Air Ministry .

Re: Starting point for ST 51

Steve Helmick

Re: Starting point for ST 51

frank mccune

Re: Starting point for ST 51

Balsa Butcher

Re: Starting point for ST 51