ST 51 CL Setup Data

I am looking for some setup data for the current ST 51 CL in stock configuration.

Anyone have any recommendations?

V/r

Send it to Tom Lay. When you get it back it will definitely be ready to go. Tom seems to "have the touch" with these motors, as well as a great many others.

Bob,
Stock: 5% nitro, 12X5 rew up Play with compression to see what's best in your area.

But I agree with Sir Dirty Dan........ oh...... my God, I said THAT????
Tom Lay has the magic touch with these.
Bill <><

At least for the "Italian" version, breakin is very important.

George Aldrich said that the ring gap was too small, and that this caused some problems when the engine heated up and the ring expanded. His advice was "For a new ring, it should be .003"/.004", at the top of ther stroke position. (TDC)" quoting directly from GA (including typo!)

End gap on the ring of ST 51s is indeed a deal killer. Both of the motors I had were too tight in this area, one ring being nearly an interference fit.

I ended up liking the Rev-Up 11-6EW, unadulterated SIG "Champion" 10% fuel, Thunderbolt standard long (idle bar is probably okay as well) and a .270 or so venturi with ST NVA running through it. Tried bigger venturis, they worked fine but mileage went down and I saw no advantage to them.

Also tried mentioned fuel pumped up to 11% castor, 11% Klotz. No apparent advantage, too much hassle.

I still say that sending the engine to Tom Lay is the best choice. While I liked my ST 51s I was always a little envious when hearing and seeing Alice Cotton-Royer's T&L ST 51 do its magic.

Bill,

Don't let agreeing with me become a habit!

LAST EDITED ON Feb-20-04 AT 04:25 PM (CDT)
 
I have run a Tigre .51 in my colossus for 5 years now. Only mod. was to add 1 head gasket and my own sprinkler venturi.It has four holes around the venturi. Run a Brian Eather 3 blade.11.5-4.7. Runs great run after run.It`s been trouble free period.

Gordy

I have been running my G51 for four years and it runs great on my Magn and my SV 12.
I run
Powermaster GMA 5% x 22 or 10% x 22
1 head gasket
Dixon Venturi with NVA low in the casting
Phelps 12 1/4 x 5 1/4. It runs like a watch.
I have replaced the ring once and put the gap at .004.
Love it
Wayne

I've run ST .51s from 1993 through 2001 off & on I have probably 1000 flights on these .51s. Mine were reworked by George Aldrich my best was #3 Tiger setup as a clearbore .210 " venturi with around .0018 head shims running an Eather 11.6x4.5" wide blade or an APC 11x4 . Set at 9,800 rpm ground launch . Sluged through the WHOLE pattern never breaking out of a 4 cycle.The fuel was Taffinders 10- 24 PA ,RedMax 10-22 pattern fuel, Sig 10% Champion Fuel.
But Keith Varley's Tiger sounded just as good as mine & his was Stock except with one extra Head Gasket. Jerry Eietchen's was a Dixon mod.& it was the nicest sounding .51 I ever heard. I don't think you can miss.

Bené Rodrigues has been flying the FAI WC's for years with a stock .51.

At least he says it's stock, but there are rumors that it aint.

My buddy Chicão flew a truly stock one, with home made fuel, I don't remember if it was 20% or 25% castor, and 0% nitro.

Oh, yeah, he used an extra glow plug gasket (!)...

After much fiddling with compressions, needle valves, fuels etc mine is now absolutely box stock with 25% all castor (with 20% castor the 4 stroking was very unstable), zero nitro and a Zinger 12x5 wood. I also use a Bolly CF After Muffler in place of the boat anchor. At ground revs of about 8000 it 4 strokes the entire flight and hauls 59 ounces and 830 sq inches with ease (very similar to my Stalker 61). It's also by far the most economical engine I've ever seen.

Don't fail to try an APC 12-5, full or clipped to as short as 11.5". My first one was Dirt's #1 G.51, came with a no-idlebar T'Bolt, and it would start and run about 30 seconds and quit. I changed to a new T'Bolt with idle bar, and it hasn't missed a stroke since. The venturi has .285" scratched on it, as I recall. I bought a new Chinese G.51 last month and sent it to Tom Lay, and had a Bowman ring installed. I don't think he messes with the stock rings. Seems like the safe thing to do, and by the way, the G.51 Stunt is $90 in the latest Tower weekly catalog. I'd love to try one with a blocked boost port. Steve

Further to the topic,I remember reading in an old issue of Stunt News in the Sport Flyin section by Fred Brigeman that Henk de Jong
had written an article in Aero Modeller about taming the ST G51
does anyone have that article?

Henk de Jong is our national (Netherlands) Stunt champion for decades in a row and my stunt-mentor. He did not fly many years with the G51 as he started using an engine made by Eli Rosenberg of Israel long ago and does not want to use anything else because of it's performance. He still rates the G51 as an excellent stunt engine. Henk published his Blue Pearl design in Aeromodeller febrauari 1996. This used a G51 and some but not much comments were made, mainly that you should adjust the model speed not by adjusting the needle, but by using a different pitch prop, or change compression ratio and venturi diameter, where more head shims and a smaller venturi both allow to use more propeller pitch. He carries different size venturis in his box and changes them aftre a test flight if needed. Henk says the G51 had the same power as the ST60, but needs to rev higer and therefor uses a lower pitch of around 5 inch. You should be able t contact Henk at [email protected] but I believe at this time he is experiencing difficulties from his mailprogram.