Back when the ST46 was real popular the really good pilots were pouring the nitro to the ST46 to make it perform.
At the end, yes. For most of its life people were running them on Fox Superfuel or something similar. It was only after we saw a few examples of Fox 35s on 15% (with dramatically increased power) that very many tried 15 and 20 in the ST. That started in the VSC era (although I am sure they knew about it in the good old days of the Fox, too) which is pretty late in the game. The very last gasp of the ST was the 91 Team Trials with David coming in 6th with an ST on 15% Cool power with a bunch of oil added to it. That's a very remarkable achievement up against the VFs and OPS 40s. But even David couldn't overcome the performance deficit.
Oh, for the good old days where you whipped for a lap and a half before the hourglass, swooped into the first corner as soft as you could, got up on tiptoes with your hand as far up as you could get it, then yank it down to your shoulder for the second corner, and then down to your knees for the third corner. Or start the overheads the same way, and end up with your hand almost on the ground by the end. So nostalgic it brings a tear to my eye. But not in a good way.
One thing I do know - the last thing in the world it needs it *detuning*! We never had a problem with too much power, that's for sure. That's why even in the late 70's almost everybody was looking for a replacement, and the airplanes got progressively smaller until the bitter end in ~1990. Also led to the New Jersey "Schneurle Wars", then the stop-gap of the ST60 until 88 or so when piped engines came along. Mostly just to get the same performance you got with an ST46 on those rare occasions that it ran perfectly. If nothing else the LA has a slug-piston and is likely to run the same way every time. Even if it didn't have more power, or at least more effective power (since you run much less pitch than you could ever get away with on the ST), that alone would make it a no-brainer as far as choosing. You can always make the airplane smaller if you want more performance, and with the high-rev/low-pitch you have much more leeway on the airplane design. With the ST and similar engines the airplane size was much more critical, and as you got smaller, the performance went up but getting a perfect engine run got even more critical, because a little off either way and the system performance fell off dramatically. That's why my cohorts and I never went to the 60- the optimum airplane was bigger than we felt comfortable with and putting it in a 46-sized plane was clearly demanding that you got it *perfect* every time.
Thanks for the nice comments on the ST setup instructions (which, to summarize, were leave it stock, find a good ring, and use a .173 venturi and 10% 50/50 and a cleaned up Rev-Up 12-6 - and the only important bit being the ring). But I would hasten to point out that this was an accumulation of knowledge that others had figured out over the 15-20 years it was being used seriously for competition. My sole contribution was the second o-ring below the annular manifold on the venturi, but I am not sure how much of an improvement that was. Otherwise I was just the editor/"fact checker" for the information, and posted it about 20 years later when someone invented the internet.
Brett
Topic: ST46 vs. OS46LA (Read 1162 times)
