RC Tank Warfare community hobby forum

Shame that two strokes went into oblivion when emissions hit the headlines, they were brilliant for motorcycles, the demonic Moto GP bikes in the hands of riders like Mick Doohan were poetry in motion.

Wibbly don't talk to me about Two Strokes,
I was pretty much brought up on four strokes, And in common with most bikers I had a particular corner that I tried to take leaned over far enough for the pegs to ground out, I bought this second hand plus Kawasaki KR1S,
It was overdue an engine rebuild but I had to take it out once before the strip down,
Down the hill to the CORNER clicking down the gears almost there and backed off the throttle into the over run,
What do you mean there's no engine braking on two strokes
Thank goodness for grass runoffs and leathers.
Still I got a good price for it after a rather more extensive rebuild than originally planned
And less we forget Max Dehner made both his name and his fortune with two strokes
Shaun.

wibblywobbly wrote:Shame that two strokes went into oblivion when emissions hit the headlines, they were brilliant for motorcycles, the demonic Moto GP bikes in the hands of riders like Mick Doohan were poetry in motion.

Most diesel locomotives are 2 stroke engines with either a turbo large enough to eat a Fiat or a supercharger that can eat 2!

Marine diesels are HUGE!
I worked on a mid-size (for then) ship, 536 ' long 17,500 tons. You had doors, a row of them, in the crankcase one for each cylinder, & you walked inside to work on or inspect them. (not while it was running obviously).
Pistons were the size of 55-gal oil drums!

Class and type: Cunard Countess-class cruise ship
Tonnage:

17,496 GRT
2,499 t DWT

Length: 163.56 m (536 ft 7 in)
Beam: 22.80 m (74 ft 10 in)
Draught: 8.30 m (27 ft 3 in)
Installed power:

4 × Burmeister & Wain 7U50HU diesels
combined 15,447 kW

Propulsion: 2 propellers[3]
Speed:

21.5 knots (39.82 km/h; 24.74 mph) (top speed)
20.5 knots (37.97 km/h; 23.59 mph) (service speed)[3]

Capacity: 947 passengers

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I found this at the back of a shed the other year. I dragged it out poured some fresh petrol in and kicked the kick start a couple of times.
Nothing!
When I have time I'll try and get it back on the road.

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jackalope wrote:That article doesn't mention drive wheel diameter unless I missed it. That goes into figuring the tractive effort for both steam or diesel engines. The larger diameter the more wheel surface contacts the rail head which helps the engines dig in.

Case in point look at the wheels on an EMD SD9043MAC which are much larger diameter then say a GE 4400ACE engine. Both have about 4400hp but the EMD engine will pull where as the GE engine will just spin it's wheels. I know, I've ran both! LOL!

The flip side is the freight locos (steam) tend to have smaller wheels but more of them with expressions passenger having the bigger ones.

Saying that on Diesel/electric locos the high speed ones (125mph +) are with the exception of the class 89 bo-bo where as heavy freight are almost always co-co.

tomhugill wrote:

jackalope wrote:That article doesn't mention drive wheel diameter unless I missed it. That goes into figuring the tractive effort for both steam or diesel engines. The larger diameter the more wheel surface contacts the rail head which helps the engines dig in.

Case in point look at the wheels on an EMD SD9043MAC which are much larger diameter then say a GE 4400ACE engine. Both have about 4400hp but the EMD engine will pull where as the GE engine will just spin it's wheels. I know, I've ran both! LOL!

The flip side is the freight locos (steam) tend to have smaller wheels but more of them with expressions passenger having the bigger ones.

Saying that on Diesel/electric locos the high speed ones (125mph +) are with the exception of the class 89 bo-bo where as heavy freight are almost always co-co.

In diesel electric engines it's their gearing that determines the top speed, much like in an automobile.

The Union Pacific had, and still does have fast frieght steam locomotives. Though now days they are excursion trains. They have a 4-8-4 and a 4-6-6-4 and are currently restoring a 4-8-8-4 steam locomotive to service! All of the were designed to haul primarily frieght at high speed. Now high speed is a relative term because in the 30's and 40's that meant speeds up to 60 mph where as now days even though most frieght is limited to the same speed as back then it's no longer considered "fast"

Eastern Front wrote:

jackalope wrote:That article doesn't mention drive wheel diameter unless I missed it. That goes into figuring the tractive effort for both steam or diesel engines. The larger diameter the more wheel surface contacts the rail head which helps the engines dig in.

Case in point look at the wheels on an EMD SD9043MAC which are much larger diameter then say a GE 4400ACE engine. Both have about 4400hp but the EMD engine will pull where as the GE engine will just spin it's wheels. I know, I've ran both! LOL!

Don't forget that the trains gain traction through the use of sand...the "Hood" is where the sand hopper is, the sand is shot onto the tracks with compressed air through funnels in front of the drive wheels----Nifty!

Cheers!

Yup! Sand also helps with braking and dynamic braking too. Helps keep the wheels from sliding.

Crankshaft