When I was a design engineer working for da man, we called it "bleeding edge". We generally tried to contain enthusiasms for too many really innovative features in a product: too few and you didn't move forward fast enough; too many and your shiny new product never got off the production floor, or it spent all of it's life in service.
Pushrods or... oh, never mind ;-)
And the model should be that extremely advanced Bristol engine of the
1950s, used in a variety of cars, that had 6 cylinders, 12 valves, and 18 pushrods.On 6/22/2015 10:16 AM, Leon Fisk wrote: ...
That's a great example of adding a feature because we CAN, whether or not we SHOULD. The engineers are having too much say.
Remember when Land Rover meant minimal features and maximum reliability? Such that it was THE safari vehicle.
Bob
I've worked on stationary diesel engines that had three cam lobes per cylinder :-)
But we were talking about *advanced* engines. That's all about pushrods, if you've been following the unending discussion. d8-)
So, how many pushrods did it have per valve?
Only one push rod per valve.
In thinking about it there may have been 4 cam lobes per cylinder :-) The extra ones were for the injection pump and (I think) there was a fourth that operated the air start valve.... but it was a long time ago :-)
I believe that they were considered "advanced" back in their day. 750 Kw @ 900 RPM. Certainly makes some of the more modern push rod engines look anemic :-) Some versions even had "variable valve timing".... so they could run in the other direction :-)
You realize, I'm sure, that I meant "advanced" in an ironic way. d8-)
The historical variations on IC engines are pretty amazing. There's very little going on that han't been tried before. The big difference now is the electronics.
I owned one of those 18-pushrod Bristols, BTW, and eventually learned (was taught, actually, by a Bristol expert) how to keep those valves adjusted. They needed to be adjusted almost constantly. The lash on the exhaust side, where there were two pushrods and two rocker arms for each valve, would open up in a month of regular driving. That is, unless you had a recent valve job, in which case it would first
*close* up. Sheesh.
When my Dad's B-29 ditched, it had 1 functional engine. B-29s couldn't fly on 1, they just descended slowly.
David
As I did when I said "back in their day" :-)
Apparently everything is electronic. My wife got a notice to bring her Honda (car) into Honda Service to have the "Transmission Software updated".
I've always wondered about Roll Royce's reputation coming from a country where valves had to be adjusted weekly, where SU carbs were invented and the amazing Lucus electrical system originated. I remember looking at a, probably, late 1930's Rolls in a vintage car place in Miami and under the hood it seemed to be about as prosaic as my 1937 chevy. I've always wondered if that might not have been their secret :-)
There were several issues behind their success. Behind it all, it was the unmitigated stubborness of Sir Frederick Royce.
A couple of bits: The bore and stroke of the early engines was engineered by taking the bores and strokes of the successful cars of the time and averaging them. d8-)
Development consisted of running an engine harder and harder until something broke. Then, that part was beefed up, and the engine(s) were run again until the next part broke. And so on.
Well, the article said that they ran out of gas :-)
From the date I am assuming that your father would have been flying the earlier carbureted models and I never saw one of those. By the time I worked on them they were all injected and probably the last version to have been made.
Certainly the engine failures that I read about were pretty well cured as I don't remember an excessive number of engine changes for that sort of airplane although I d remember that an engine change, working
10 - 12 hour days was a several day job. and anything that you did on the engine was difficult to get to.
Basically, yes. They were told POW camp where they dropped the supplies was in a valley, but when they entered the valley, the camp was right underneath, so they had to make another run for the drop. The camp was already near the limit of range for the B-29, so they were low on gas. Then when one engine went, they had problems transferring fuel to the remaining engines.
The 444th Bomber Group had been operating out of India but as airfields opened up in the Pacific, they were transferred to Tinian, which is where my Dad joined them. They also got new B-29s shortly after that.
David
And you end up with a low RPM relatively low compression ratio, six cylinder engine :-) Sort of like my old Chevy :-)
Sort of. Except that it isn't a Chevy. And your Chevy wasn't a Rolls-Royce. d8-)
In those days, and even up to today, Rolls-Royce was conservative in concept, but superlative in execution.
.......................
RR developed the Merlin by strengthening whatever broke too:
-jsw
My sister got on a 4 engine plane in the south Pacific in 62 maybe. The plane got just about half way to Hawaii and lost both engines on one side.
They turned around and came back home. Let everyone go home when a phone number was available. Six hours later every one loaded up and flew to Hawaii and from there to Oakland. Tough trip. Just under
24 hours one way. 11 1/2 and 11. Boeing had to make a long range jet to get anyone out or back faster. 727 Long. We had a 0.7 mile long runway.Mart> On Sun, 21 Jun 2015 23:12:36 -0400, snipped-for-privacy@snyder.on.ca wrote: >
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