The Radial engine was once the pinnacle of internal combustion engine design, but has gone mostly extinct. What happened? The Radial first ousted the Rotary, then to a large extent the inline engines (V12's) before the Radial itself was ousted.
In this video we briefly go through the history of the radial and we also take a bit of a deep dive into radial engine design and see what made it such a great engine.
VIDEO HERE (15:05 minutes)
I haven't watched the video but I did turn wrenches on radial engines for a couple of years (R1820).
ReplyDeleteGas turbines are better for that size/power IMO.
Agreed, but you can't use a turbine piston for an ashtray.
DeleteI was over in the ROK working on project to replace the ROKN S-2 Trackers with new built P-3C's back in the 90's. Those S-2's were twin engined with Wright Cyclone R-1820 nine cylinder radials and on some mornings they would have 3 or 4 aircraft all fired up. I don't guess I'll ever hear that many running radials that were going on an actual mission ever again.
ReplyDeleteOne of your better video finds at least in terms of what I find interesting! A lot of the firearm history videos are good too but often the narrators leave something to be desired . . . . but that's just me.
ReplyDeleteNo, not just you.
DeleteIt's quiz time! Why do radial engines have an odd number of cylinders in each bank? So, for example there are 7 cylinder radial engines and 36 cylinder radial engines that are 4 banks of 9. but there are no 6 or 8 cylinder radial engines? Answer below, but try the question before looking.
ReplyDeleteAnswer: It's a matter of engine timing. In a four-stroke engine, each cylinder is fired every two rotations of the crankshaft. So, with an odd number of cylinders, the firing order is bang skip bank skip bang skip.... If there were an even number, the same even cylinders would be firing and the odd ones would be skipped. I can envision an electronic circuit that can handle the timing of an engine with an even number of cylinders in a bank, but that would be overly complicated compared to a simple mechanical mechanism that will properly fire an odd number of cylinders per bank. General Motors introduced a 2-stroke 8 cylinder radial engine, the X-350 (4 blocks each having 2 bores. It is described in an engineering report by GM's then chief engineer Charles Kettering (later of Sloan-Kettering fame with Alfred Sloan--GM's founder and first CEO). It did work well, but all research stopped when WWII broke out. I am unaware of other efforts to make 2-stroke radials.
I've been chewing on that since Lackland in 73. When they cut us loose for an hour I Ran to the museum to oggle those radials. Can't believe it's that simple,, wadda dummy..
DeleteThanks a lot. One of life's mysteries solved..
There are a couple of great vids on YT featuring a wooden cutaway radial engine, the guy goes over the functions of it all, including the odd numbers of cylinders thing:
ReplyDeletePart 1:
https://youtu.be/qjnQKXNPsk4
Part 2:
https://youtu.be/R71Xhrkc3EQ
Most radials are/were more damage resistant than an in-line water-cooled engine.
ReplyDeleteThe big issue, of course, is that the huge multi-bank radials that came out during and after WWII are more labor intensive than turbo-props, and much more finicky regarding fuel contamination.
Cool video.
If you took a chunk out one of those radial engines you’d have an H-D motor…
ReplyDeleteHoward Hughes Spruce Goose had 8 28-cylinder radial engines….
ReplyDeleteAt my funeral there won't be any weepy songs, just the sound of a recip coming out of speakers in the ceiling.
ReplyDeleteIf you want to see something interesting, check out via search engine the “sleeve-valve radials” like the Bristol Centaurus. Amazing British innovation. The gear trains were incredibly complex. BTW think about the job required to change spark plugs on the R4360s as used in the B-36: 336 plugs (it was dual-ignition, and each engine had 28 cylinders).
ReplyDeleteSleeve Valve cutaway--
Deletehttps://www.youtube.com/watch?v=v9IpQeVdDS4
Bristol Centaurus at full throttle (at the 1:43 mark and later)
https://www.youtube.com/watch?v=ZRS5sa3n_o8
Just FYI: 2 stroke diesel radial stationary engine for pumping stations; https://en.wikipedia.org/wiki/Two-stroke_diesel_engine
ReplyDelete