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.
If you like this video you will love this one - WWII Aero V12 Engines Design Explained :
https://youtu.be/Tz8vTnl-pAU
Chapters
0:00 The "Magic" of the Radial
0:21 Humble Beginnings
0:49 The Rotary Engine (Pros)
1:34 The Rotary Engine (Cons)
2:01 The Rise of the Air-cooled Radial
3:02 Basic Radial Engine Design
3:40 Radial Firing Order
4:03 Radial Firing Interval
4:59 Radial Crankshaft
6:17 Radial Valve Operation
6:36 Radial Primary Balance
7:04 Radial Secondary Balance
10:46 Radial Disadvantages
12:13 The Fall of the Radial Airplane Engine
14:03 Post-War Radial Applications
14:19 Modern Radials
Creative Commons attribution:
"Radial engine timing" animation by Stoianovici (https://commons.wikimedia.org/wiki/File:Radial_engine_timing.gif) license (https://rb.gy/660n3a) zoom, cropped, arrows & text overlaid
"Radial engine large" animation by Duk (https://en.m.wikipedia.org/wiki/File:Radial_engine_large.gif) license (https://rb.gy/660n3a) arrows & text overlaid
"4StrokeEngine Ortho 3D" by Zephyris (https://commons.wikimedia.org/wiki/File:4StrokeEngine_Ortho_3D_Small.gif) license (https://rb.gy/660n3a) overlaid lines & arrows
Secondary unbalance force in a 7 cylinder radial by Pasimi (https://commons.wikimedia.org/wiki/File:Engine_Balance7.gif) license (https://creativecommons.org/licenses/by-sa/4.0/deed.en) overlaid text
Boeing-Stearman E75 N5729N by Julian Herzog (https://en.wikipedia.org/wiki/GNU_Free_Documentation_License) no changes
Salmson 9Z by Duch.seb (https://rb.gy/660n3a) overlaid text
Rotary engine animation by MichaelFrey (https://creativecommons.org/licenses/by-sa/4.0/deed.en) overlaid text & arrow
Rotary engine animation by MichaelFrey (https://rb.gy/660n3a) increased spinning speed
Old Flywheel by Andrew Eaton (https://creativecommons.org/licenses/by-sa/2.0/) overlaid cross
Rolls-Royce Merlin by JAW (https://rb.gy/660n3a) overlaid text
LeBlond 90-5F by Darkroom (https://rb.gy/660n3a) no changes
BMW 132 (radial conrods) by Kogo (https://en.wikipedia.org/wiki/GNU_Free_Documentation_License) no changes
XK engine camshafts by HReuter (https://creativecommons.org/licenses/by-sa/4.0/deed.en) overlaid cross
Piston by S. Diddy (https://creativecommons.org/licenses/by/2.0/deed.en) no changes
Crankshaft by Alex Kovach (https://creativecommons.org/licenses/by/2.0/deed.en) no changes
Pleuel-Käfer (conrod) by Benutzer:Thomas Ihle (https://rb.gy/660n3a) no changes
Crankshaft two stroke Engine by Werntec (https://en.wikipedia.org/wiki/GNU_Free_Documentation_License) no changes
Conrod4M5ms by Bryllig (https://creativecommons.org/licenses/by-sa/4.0/deed.en) stopped, paused
Elsbett-3cyl by Dan Wesson (https://rb.gy/660n3a) no changes
Republic P-47 Thunderbolt by Eric Friedebach (https://creativecommons.org/licenses/by/2.0/) zoom
F4U-5NL Corsair (NX43RW) by Alan Wilson (https://creativecommons.org/licenses/by-sa/2.0/deed.en) zoomed in slightly
F6F-5 Hellcat by David Merrett (https://creativecommons.org/licenses/by/2.0/deed.en) no changes
Spitfire Mk XIV by David Merrett (https://creativecommons.org/licenses/by/2.0/deed.en) no changes
BMW VI by W2k2 (https://rb.gy/660n3a) no changes
"Biggest radial cutaway" by Phil Genera (https://creativecommons.org/licenses/by-sa/2.0/) zoomed in
Pratt & Whitney R-4360 at Kalamazoo Air Zoo by D. Miller (https://creativecommons.org/licenses/by/2.0/) zoomed in, text overlaid
CL215 43 Grupo by Javiramos43 (https://creativecommons.org/licenses/by/3.0/deed.en) no changes
Creative Commons video attribution:
Sopwith Camel fires up its engine by scribex (
https://youtu.be/vx8SgJTQh34), License CC-BY
Sopwith Camel Run Old Warden 22 September 2012 by Oldwardenman (
https://youtu.be/LzqswhHF12E), License CC-BY
Sopwith Camel Run 2 Old Warden 22 September 2012 by Oldwardenman (
https://youtu.be/knfADySOEL0), License CC-BY
Gyroscopic precession demonstration by MITK12Videos (
https://youtu.be/iaauRiRX4do), License CC-BY
Bombing Missions, 1944 220451-07 by footagefarm (
https://youtu.be/z9mh-sD-kzE), License CC-BY
RAF Spitfires Taking Off by footagefarm (https://youtu.be/EsJgn1Me5I), License CC-BY
B 17 b roll by Arizona Commemorative Air Force Museum (
https://youtu.be/NJj8gXRVcW0), License CC-BY
Radial at National Air & Space Museum, Dulles by iros532 (
https://youtu.be/v704wzRp5pg), License CC-BY
Cessna Aircraft Wings for Doubting Thomas (
https://youtu.be/cpF8yDJNBYA), CC-BY
Whiskey 7 First start 2017 (C-47) by David Andruczyk (
https://youtu.be/6W9bvkos2jI), License CC-BY