Timz From United States of America, joined Sep 1999, 6632 posts, RR: 7 Reply 3, posted (11 years 3 months 2 weeks 5 days 22 hours ago) and read 2800 times:
This may not be quite right, but close enough: a piston engine has pistons. You know what they are, right?
But there are lots of different arrangements of piston engines. Your car might have four pistons (in four cylinders) in a row along the crankshaft, with the axes of the cylinders parallel; some aircraft engines used to use that arrangement, but it's fairly rare now. V-6's and V-8's are common in cars but rare in aircraft. Radial engines are just another possible cylinder arrangement of a piston engine.
Maybe 98% (?) of piston engines flying today are air-cooled, unlike your car (probably). That's one reason for the radial arrangement.
LZ-TLT From Germany, joined Apr 2001, 431 posts, RR: 0 Reply 4, posted (11 years 3 months 2 weeks 5 days 22 hours ago) and read 2770 times:
To add to Timz's comment:
The Junkers Ju-88 has 18-cylinder Y-form engines(3 banks a 6 cylinders arranged in an Y form around the crankshaft)
While building the Tu-4(B-29 clone), the russians considered the use of their own developed, 48-cylinder X-form engines(4 12-cylinder banks arranged in an X-form around the crankshaft). However, the intention was cancelled due to unreliability and maintenance problems of these experimental engines.
The french pre-WWII Caudron racing aircraft were equipped with straight(not V) Renault 6 or 8-cylinder engines(common in cars, but not that common in aircraft, even in those years)
ALL WWII watercooled engines - the DB series(powering the Me-109), VK-105PF and VK-107PF (all Yak fighters), RR Gryphon/Merlin(Hurricane/Spitfire/Mustang), Allison(Curtiss Kittyhawk), just to mention the most popular ones were V-12's mounted inverted
PPGMD From United States of America, joined Sep 2001, 2453 posts, RR: 0 Reply 5, posted (11 years 3 months 2 weeks 5 days 21 hours ago) and read 2763 times:
Well that I know of there is one one readily made radial engine that is the Russian M-14, its gear backwards, so the prop spins the other way, which I think is couter clockwise from the pilots seat. They are used in the Sukoi series of aerobatic airplanes (SU-29 and SU-31), and in the Pitts Model 12 made by home builders. Its a rather fine engine that is much cleaner than the old radials thanks to the clean kit. Oh one intresting thing the starter is powered by air pressure so its not uncommon to see Dive tanks in the hanger. I know that I spent several hours starting one as it neared time to do the certification flights.
Timz From United States of America, joined Sep 1999, 6632 posts, RR: 7 Reply 8, posted (11 years 3 months 2 weeks 4 days 23 hours ago) and read 2716 times:
No expert on Ju88s, but I assume 99.9% (or maybe 100%) of them had either BMW 14-cylinder two-row radials or Junkers Jumo inverted V-12s. I think the Jumo 222 that appeared in a few prototypes was a 24-cyl-- 6 banks of 4-in-line.
I'll try another spelling: Griffon?
I guess all Rolls-Royce and Allison V-12s were right-side-up, weren't they? By which we mean the crankshaft was at the bottom of the engine with the cylinder banks forming a 60-degree vee above it-- the usual arrangement, in other words. But German WWII V-12s were all? inverted.
Dash8King From Canada, joined Nov 2001, 2742 posts, RR: 11 Reply 9, posted (11 years 3 months 2 weeks 4 days 19 hours ago) and read 2688 times:
Ok thanks a lot, I now have another question how can you tell by looking at it if it is a piston or a radial engine. Like a C150 is Piston but a DC-3 is Radial so how can you tell by looking at it. BTW, yes I did know what a piston was.
Dash8King From Canada, joined Nov 2001, 2742 posts, RR: 11 Reply 11, posted (11 years 3 months 2 weeks 4 days 15 hours ago) and read 2681 times:
Wow ok thanks a lot PPGMD I have all the answers to all the questions I asked so I thank you all for responding and passing on information to me which I am sure I will be able to pass on to someone too.
Broke From United States of America, joined Apr 2002, 1322 posts, RR: 3 Reply 12, posted (11 years 3 months 2 weeks 4 days 9 hours ago) and read 2676 times:
A few notes on radial engines that you may not know.
U.S. radials are designated with the letter "R", the number following the "R" is the approximate displacement in cubic inches.
Pratt & Whitney radials generally have 7 cylinders in each row.
Wright Aeronautical radials generally have 9 cylinders in each row.
There are very few radials with an even number of cylinders in a row; the reason is vibration and resonance problems.
Radial engines are turned over on the starter a couple of times before turning the fuel and ignition "on" to pump any oil that has accumulated in the bottom cylinder(s) out of that cylinder(s). Trying to compress oil on the start is a good way to blow the bottom cylinder (As known as a "Jug") right off the engine.
Oil in the bottom cylinder(s) is also the reason why radials tend to smoke badly during the start.
Timz From United States of America, joined Sep 1999, 6632 posts, RR: 7 Reply 13, posted (11 years 3 months 2 weeks 4 days 5 hours ago) and read 2651 times:
Assuming the radial engine is a four-stroke cycle (as most are, right?), then if you think about it you'll see that a single-row radial pretty well has to have an odd number of cylinders. Otherwise you can't arrange the power strokes and intake strokes.
IMissPiedmont From United States of America, joined May 2001, 6244 posts, RR: 36 Reply 14, posted (11 years 3 months 2 weeks 3 days 18 hours ago) and read 2620 times:
And then you can add rotary engines. They are, of course also piston engines. The difference being that a radial has a fixed engine with a moving crankshaft while the rotary has a fixed crankshaft with a moving engine. Confused yet?
Is grammar no longer taught is schools? Saying "me and her" or some such implies illiteracy.