Ex.Chamber Science

[smittythewelder]

My e-mail just alerted me that someone had posted here, after a long period of inactivity. After looking at Tom's entry, I looked back at some others.

Sam, are you still here? You indicate that the A Konigs were deflector motors before 1960, but I have a copy of Boat Sport from 1957 which has an article on the "new" A Konig. It looks just like the ones from the early '60s (other than the pipes, and having the carbs mounted vertically), and the engine internal drawing shows it to be a looper. If anyone here is restoring one of these engines and has no good access to Boat Sport, give me a PM and I'll shoot you a copy of the article.

I think I have what's left of one of these first-version blocks. You wouldn't believe it: all of the water jacketing is formed by drilling in from the deck surface, parallel to the bores!! The funny thing is, none of these holes are interconnected, except by a shallow channel around the inside of the head. The water just kind of shook in place!! This first A was rated at 25hp, which might have been optimistic, and maybe not for long. By the mid-'70s, Ron Anderson was getting something like 67hp from the single-pipe A of those days, with considerable longevity (he and Lee Sutter were running it) which is surprising, considering how spindly those crankshafts were. At one time I had what I took to be a second-generation block (raced by Jack Livie, and now in the hands of Buzz or Alan Thorsen, maybe). This version had much better cast-in water jacketing, and looked about like the early-to-middle '60s engine shown in the photo above except that it had no boost-port, just the two transfer ports and the exhaust.

[Mark75H]

Smitty, I think you are right ... 1957, not 1960

Santa brought me a book about MZ motorcycles & Walter Kaaden ... looks like Kaaden had expansion chambers on the MZ's a little before 1958 ... but really brought it together in '58 with a 20hp 125cc (10ci) racing motorcycle that had rotary valve intake, hemi/squish band cylinder head and 3 transfer ports instead of 2 ... all this to optimize the power boost from the expansion chamber

[Tomtall]

Nice format. Lets see if this link works.

http://fpp.hamradio.si/roost/softwar...alculator2.zip

May require unzipping. However I was able to just run formate as is. Click on "Exhaust calculator2" folder.

[Mark75H]

Wow, Tom ... if you surf off of that guy's links you hit some of the mother lode of 2 stroke information

Here's the Mac version (macro'ed up Excel stuff) Link to Mac version of the pipe/motor calculator

[Tomtall]

This site offers some very cool software and theory.
http://www.bimotion.se/

[Mark75H]

This week it occurred to me why it was Germans that discovered the expansion chamber ... The V-1 rocket engine was an exhaust pulse tuned motor. The only compression it had was the reflection of the previous exhaust pulse leaving the end of the tube.

Here's the run down on the V-1 engine:

The fuel was propane. At the front, a group of check valves allowed a gulp of air to enter the combustion chamber which was bulb shaped. Tailing off the other end of the combustion chamber was the tuned exhaust pipe, open at the back. That's it, nothing else, (except for an on/off valve on the fuel and maybe a check valve in the fuel line).

The engine was started by opening the fuel valve and igniting the first pulse with a spark plug. After initial ignition, the spark plug was not needed ... the returning exhaust pulse hit the next fuel/air charge with enough force to cause compression ignition; the intake check valves kept the explosion from going out the front of the engine. As the exhaust traveled down the exhaust pipe, it created a vacuum that pulled in the next gulp of fresh air to the combustion chamber ... the exhaust pulse returned and ignited that ... over and over again at the rate determined by the length of the exhaust pipe .... br-r-r-r-r-r-r-r-r-r-r-r-r-r

There must have been hundreds of German engineers that knew how this worked ... they applied it to the exhaust on 2 strokes and Kaaden combined it with the correct rotary valve timing and porting for more power than anyone thought possible with a 2 stroke motor with it's exhaust port closing so late in the cycle.

[smittythewelder]

Fun to see old dormant threads revived!

Here's a boat-racing/expansion-chamber/pulse-jet connection. Jim Hallum, who engineered Gerry Walin's record-setting Anzanis in the Sixties and early Seventies, was one of the early Reg. 10 experimenters with expansion chambers (first on roadracer Jimmy Dunn's motorcycles and on somebody's racing chainsaw). In the early Fifties, while wrenching on his dad Val Hallum's A Hydro (Evinrude power), Jim's own hobby was racing control-line model aircraft. Some other boatracers were avid model aircrafters, including Bob Wartinger, who was a control-line racer before getting into outboards while getting an aeronautical engineering degree at the U. of Washington, where I met him. And after Ed Karelsen retired from building boats, he took up radio-control flying; maybe still does it for all I know. Anyway, Hallum bought a Dyna-Jet Redhead pulse-jet model airplane engine . . . invented by Bill Tenney. Jim got his plane going 150mph, went back to a big meet in the Midwest, met Tenney, found out about Anzanis (this info is only roughly reliable; if strict accuracy is essential, get hold of Jim).

Anyway, today Jim has returned to his early hobby, and builds and flies pulse-jet powered models. How's that for a tie-in, Sam?!!

[Powerabout]

Maybe we should look into Dieter Konigs family to see what they were doing during WWII

[Mark75H]

Maybe we should look into Dieter Konigs family to see what they were doing during WWII

Its in the Konig History thread ... not involved in any of that.

[OUTBOARDER]

But I can't work out why his reeds are chuffing at the end of the inlet stroke, give me that M6 spanner I want to have a look at them.

As the piston is on it's way down the pressure in the crankcase builds up and at some point overcomes the inlet pressure wave thru the carb and the reeds slam shut. The air/wave that was flowing thru carb rebounds of off closed reeds back out of carb as a result. "Chuffing"
Happens more at certain rpms than others, typically at lower rpms.

After getting on plane the 45ss the engine has fuel puddled in lower pan from this.

Can cause a 2-stroke engine to load up with gas mixture from picking up fuel twice thru carb.

Ideally the over rich condition can help with engine accelerating, like what a accelerater pump does in a automotive carb. The rich condition also lowers egt temp and lowers tuned rpms of the pipe which helps with making effective rpm range larger.