ST V51

Just picked up a very nice ST V51, bushed bearing - two rings, from Ebay. Anyone know if this is a good stunt motor? It came without a carb or venturi and is cross drilled for spraybar, can anyone suggest the appropriate venturi size. It has the usual 'Chromed'logo on the crankcase - dont know if it is though. It does have the letters AAA stamped on the edge of one lug, does this mean anything to anyone - dont say I can call triple A if it breaks down!
Exhaust stack is flat on front edge with the other rounded with a tapped hole, where can I get a muffler?

How do I add jpeg to this?

Thanks guys.

I've used these same engines with venturi's from [email protected] He also sells them on EBAY. I don't know if they will work for you or not as you implied it has been cross drilled. Might have to go with the venturi from a current G 51 Super Tigre as they will fit. SSW can also help you with a venturi as well. I have found that these engines run very well for the type of flying that I do. I am not a competitor, just a sport flyer. Bill

>I've used these same engines with venturi's from
>[email protected] He also sells them on EBAY. I don't know if
>they will work for you or not as you implied it has been
>cross drilled. Might have to go with the venturi from a
>current G 51 Super Tigre as they will fit. SSW can also help
>you with a venturi as well. I have found that these engines
>run very well for the type of flying that I do. I am not a
>competitor, just a sport flyer. Bill

TY,
When I said 'drilled', this is not a subsequent mod but an original drilling thriugh a raised boss on the side of the venturi housing, there is no provision for a 'sprinkler' type system

LAST EDITED ON Nov-28-03 AT 11:38 PM (CST)
 
By "TY", do you mean Thank You, or should it have been Tryhard? I did not respond and saw Ty and got confused, which is getting easier each week.

sorry for the shorthand! should have said thank you.

Haven't had any experience with the bushed two ringed version, but the non-sprinkler ones were early, IIRC, and should be timed pretty good for stunt. Many sources for venturis out there, ask here in the "classifieds" might get the quickest response.

Bill <><

I have used this version of the ST .51 with a .280 venturi and 25% castor/synthetic blend fuel. The stunt runs were very good and I enjoyed using this motor in a number of airplanes. As a matter of fact, I just ordered a .280 standard delrin venturi from Stuka Stunt to replace my homemade one. Initially, my motor's rings were shot so I got replacement rings from Frank Bowman and re-ringed the motor. Other than my own personal experience with this engine, I don't know how popular this engine was/is in the stunt community. Good luck with your motor!

Mike

I have a v51 like yours it came with a super tiger ventur size is .290. My engine runs great with a 11 1/2 6 air master, brake like a bull (2/4/2). Has good lap times, 5.8 sec. to low 6s on 60'wires. Engine RPM lower than that of the V60,56,51 light case , I set my engine at 7800 RPM and it's great. I also had to rering my engine, got rings from Frank B. I also fly most weekend with Frank, he's a big help for me. Good luck Mike

Had a V case twin ball bearing .51 in a 60 oz Legacy. It had a through the venturi ST spray bar, unknown venturi diameter.
Very good runs, I thought pretty similar to the ST 60 swinging a 12-6 BY&O. Power was adequate for the Legacy in mild wind conditions though it was much improved with the installation on a ST 60 which is, of course, a drop in.
Lets say 80-90% of the guts/power of the ST 60. All in all a pretty decent engine, usually available for a lot less than the ST 60. Mine would have been quite happy on a slightly smaller, ligher airplane.

thanks for the information.
Having looked further into the internals of my engine it appears to have only had one or two runs at most. I can see that the top ring has not bedded in yet and the lower ring is still black. Did you have problems with the rings from new?(or maybe it was a used motor) Does Frank supply rings alone or does he need the whole motor or piston/cylinder assembly, I live in UK.

The cylinder head in this motor is massive, weighing 1.4oz with the plug, and is beautifully machined but has no gasget or shim although the compression does not feel excessive. Is yours the same?
Thanks.

My motor was used when I bought it and had a good bushing but, as mentioned earlier, weak compression. Frank Bowman does not need the piston and linner, and can fashion most any ring imaginable for you.
You might want to get a caliper reading on the old rings and provide the info. to Frank upon your order for a "proper" fit to the piston ring groove. I once asked Frank do some machine work on an ST .60 for me and he changed the existing ring and informed me that the motor had an undersize (thickness) ring fitted in it. Frank replaced it with the correct ring for that particular series of the ST .60. I recommend Frank's services without reservation. He is as you would say in England, a "Very Good Chap."

Mike:)

I'd suggest that only the top ring be replaced on any of the early 2 ring Tigres. With 2 new rings with good tension, there's too much piston drag, so you run a fair chance of wearing out the wristpin bosses in the piston. So use a worn, loose ring for 'oil control' in the bottom groove. Helps to keep the piston wear under control. My guess is that this is the reason for all of these manufactured after the first series having single rings. Tom H.

Tom H