Hi Bill,
I will attempt to keep this short & pithy.
These horsepower numbers (I’m not trying to be rude) that used to fly around the racing community were generally based on a misunderstanding of the entire concept of what it took to make a boat go faster. Basically, the boat load curve for a typical boat was a 2.5 exponent as best I can recall. Keep in mind that circuit racing is all about matching the propeller to the engine characteristics keeping in mind the boat load curve and, of course, the available power out of the turns.
Your bhp numbers remind me of stories about fishermen who go out and catch a 15” bass, and by the end of the night at the bar the damn thing grew 10 inches! Now, I don’t have intimate knowledge of what you guys built at #38 and the only numbers I will quote are corrected (SAE Standard) bhp numbers.
Let’s start with the stackers. Keep in mind that they relied primarily on acoustics (based on organ pipe theory) for any bhp increase of the stock configuration. I am assuming that you are referring to the six single-stack 8 degree megaphones which had a very narrow rpm range in which they were “on the pipe.” By the time they got to 6000 rpm the power was falling off very badly (see chart below). None of those engines with the Kiekhaefer internal reed block ever saw 160+ bhp on gasoline. It was a physical impossibility because of the reed block restriction and the pipe characteristics. As I told you before, I did develop a 16 degree setup (3 stacks instead of 6) that maybe broke 170 bhp, but they were never raced nor did the public ever see one (there was only one). It had a broader power curve but was never tested on a boat.
The original Twister 1 produced essentially the same peak power as did the stacker, but there was very little pipe tuning - - only pulse tuning, and that was true of everything from there on forward. All were pulse tuned. When we went to the Tillotson setup on the TII it was a major disappointment for me. We picked up maybe 10 – 12 bhp but we still had the rpm range limitations which really screwed up the prop/load issue. We did not realize at the time that the piston rings were going into resonance somewhere above 6000 rpm and that phenomena played a major role in extending the power curve to higher rpm’s.
Now you mention a TII+ built at #38 and I don’t know what that configuration was. All I can tell you is that it could not have had the same power curve as the TII+ configuration that Mert drove at Kaukauna. That engine had all kinds of tricks in it; pistons, rings, ports, etc. and it was an excellent match for the early V-6 racing engines but the durability was very short. The C6 was not competitive with the TII+ that Mert drove. That engine was a real screamer and the power range ran out to ~7800 rpm.
Now, I will show you a chart that includes four engines plus a boat load curve. Remember this is 40+ years old but has not been “recalibrated” with the special effects of Miller High Life.
http://mail.peggyspride.com/edgedesk...450&download=2
The abscissa (X-axis) is rpm and the ordinate (Y-axis) is corrected SAE bhp. Now, if you think about running a closed circuit course and the objective of minimizing lap times you can see why the stackers were lackers because of their very peaky power curve. Matching a propeller to the power curve was extremely compromising. The other extreme would be the two-of-a-kind TII+ engines that you could run laps in the 5000 to 7500 rpm range and they would completely destroy the T-2.
In closing I know how racers like big horsepower numbers but the reality of the situation is that peak horsepower is almost meaningless. For example, we built a turbo charged I-6 and V-6 and we got 350 – 360 bhp from the V-6 but an ordinary T-2 would blow the doors off the damn thing in a circuit race. This was another one of ............ big ideas and he didn’t understand the importance of torque/power relationships either. That operation along with ........... .......... -shaft gear case that had so much steering torque that no one could drive the damn boat for more than 10 minutes was ................................................ Oh well, that’s another story.
Anyway, that’s it. As I pointed out peak horsepower talk is virtually pointless when it comes to matching a fixed propeller to an exponential boat load curve. That is an important lesson that I realized early into the development of the Twister. The problem we had was extending the power curve out into and beyond the 7500 rpm range and when that finally happened it was a whole new ball game!
Take care,
Dick
From: bw@
Sent: Friday, June 14, 2013 1:09 PM
To: Dick Lanpheer
Subject: Re: stacked 1100's .....
Thanks for all the info, I didn't get bored (might have dosed off a couple of times http://mail.peggyspride.com/edgedesk...mages/e_03.gif ). Please do me a favor and tell Ted that I said Hello and wish him a Happy 80th! If you're up to it, you might ask about the 200 hp. I'm talking with a bunch of history buffs on the internet and I would like to clear up the issue of the real horsepower numbers on the BP's, stackers and Twisters, including the C6. Some of us think the HP was as follows:
1000 BP - 100
1250 BP - 125
1250 SBP (1350 direct charge) - 140
1250 Stacker SBP - 155
1350 Stacker built at #33 - 170/175
1350 Twister - 170/175
1350 Twister I (new reed blocks, exhaust mod) - 175/180
1400 C6 - 190/200
1400 TII (Tillotsons) - 190/200
1500 TIIX - 190/200
Enjoy the party, Bill
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