AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Engine question          AirTalk.org Forum Index -> Naval Aviation View previous topic :: View next topic   Author Message Max Richter Guest Posted: Sat Aug 27, 2005 3:35 pm    Post subject: Engine question Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max Back to top Gord Beaman Guest Posted: Sat Aug 27, 2005 9:02 pm    Post subject: Re: Engine question Max Richter <RichterMax (AT) t-online (DOT) de> wrote: Quote: Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max I think that the reason is that because of the comparatively large frontal area of most radial engines that a spinner is sort of superfluous...IOW. the airstream is backed up well in front of the prop hub therefore it 'makes it's own cone' in front of the prop hub therefore a spinner on the prop hub would serve little or no useful purpose...besides, you don't want the air to be scooted outside the cylinders so what purpose could a spinner provide? I'm open to other opinions...what say?... (The small hub is necessary to contain the prop pitch change mechanisms BTW...) And on second thought the Beechcraft C-45 (Expeditor) does have small spinners on their props...FWIW -- -Gord. (use gordon in email) Back to top wkambic@vic.com Guest Posted: Sat Aug 27, 2005 10:17 pm    Post subject: Re: Engine question On Sat, 27 Aug 2005 21:02:11 GMT, Gord Beaman <gord (AT) islandtelecom (DOT) com> wrote: Quote: Max Richter <RichterMax (AT) t-online (DOT) de> wrote: Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max I think that the reason is that because of the comparatively large frontal area of most radial engines that a spinner is sort of superfluous...IOW. the airstream is backed up well in front of the prop hub therefore it 'makes it's own cone' in front of the prop hub therefore a spinner on the prop hub would serve little or no useful purpose...besides, you don't want the air to be scooted outside the cylinders so what purpose could a spinner provide? I'm open to other opinions...what say?... (The small hub is necessary to contain the prop pitch change mechanisms BTW...) And on second thought the Beechcraft C-45 (Expeditor) does have small spinners on their props...FWIW They were probably not worth much. The Bugsmasher (a/k/a the Smugbasher, a/k/a the SNB, a/k/a the C-45) was not exactly a high speed aircraft. Some civilian versions of the Beech 18 were rather quick (for their time) but still were 150-170 kt. aircraft (at the outside). The cost to fashion an aerodynamic "spinner" probably was not worth the increase in performance. The S2, with which I am very familiar, had just plain, old hubs. :-) Bill Kambic Back to top Tex Houston Guest Posted: Sun Aug 28, 2005 12:06 am    Post subject: Re: Engine question "Max Richter" <RichterMax (AT) t-online (DOT) de> wrote Quote: Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max Probably because with all the rest of the engine exposed little was to be gained but just looking at photographs try these (all verified by photos). Some of these were built in quantity. Boeing B-15/C-105 Boeing Model 337 Cessna 195 Convair B-36 Lockheed L-1049 Martin AM-1 Martin P4M North American AJ-2 Ryan Spirit of St Louis Vought F4U Regards, Tex Houston Back to top Gord Beaman Guest Posted: Sun Aug 28, 2005 12:38 am    Post subject: Re: Engine question [email]wkambic (AT) vic (DOT) com[/email] wrote: Quote: On Sat, 27 Aug 2005 21:02:11 GMT, Gord Beaman <gord (AT) islandtelecom (DOT) com wrote: Max Richter Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max I think that the reason is that because of the comparatively large frontal area of most radial engines that a spinner is sort of superfluous...IOW. the airstream is backed up well in front of the prop hub therefore it 'makes it's own cone' in front of the prop hub therefore a spinner on the prop hub would serve little or no useful purpose...besides, you don't want the air to be scooted outside the cylinders so what purpose could a spinner provide? I'm open to other opinions...what say?... (The small hub is necessary to contain the prop pitch change mechanisms BTW...) And on second thought the Beechcraft C-45 (Expeditor) does have small spinners on their props...FWIW They were probably not worth much. The Bugsmasher (a/k/a the Smugbasher, a/k/a the SNB, a/k/a the C-45) was not exactly a high speed aircraft. Some civilian versions of the Beech 18 were rather quick (for their time) but still were 150-170 kt. aircraft (at the outside). The cost to fashion an aerodynamic "spinner" probably was not worth the increase in performance. But wouldn't it be self defeating to do that?...if you made them large enough to give you much of an increase in speed then wouldn't they deprive the cylinders of enough cooling airflow?...seems to me that they could have gained aerodynamic efficiency by placing the prop further forward and then narrowing the frontal air intake with cowlings. I suspect that they need all the cooling that they now have (IOW, they're designed that way) Quote: The S2, with which I am very familiar, had just plain, old hubs. :-) Bill Kambic So did the Argus with which I'm very familiar too... -- -Gord. (use gordon in email) Back to top Tex Houston Guest Posted: Sun Aug 28, 2005 12:45 am    Post subject: Re: Engine question "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote Quote: So did the Argus with which I'm very familiar too... -- -Gord. Gordon, Was the Canadair Argus an American aircraft? Oops. Regards, Tex Back to top Gord Beaman Guest Posted: Sun Aug 28, 2005 2:06 am    Post subject: Re: Engine question "Tex Houston" <texhouston (AT) pcisys (DOT) netVVV> wrote: Quote: "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote in message news:m512h1t1qlp012ibgtu1i33plnkgof3rkd (AT) 4ax (DOT) com... So did the Argus with which I'm very familiar too... -- -Gord. Gordon, Was the Canadair Argus an American aircraft? Oops. Regards, Tex No Tex, it was Brit. (and I caught the little jab! Ü) Actually it was a Bristol Britannia originally, they gave Canadair in Montreal the license to build on the original plans and modify them a bunch...musta been a humongous project...good article with what was involved at: http://www.geocities.com/cp107argus/CP107History.html This is a good site for info on this (in it's time) the best ASW aircraft in the world. -- -Gord. (use gordon in email) Back to top Tex Houston Guest Posted: Sun Aug 28, 2005 2:10 am    Post subject: Re: Engine question "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote Quote: No Tex, it was Brit. (and I caught the little jab! Ü) Actually it was a Bristol Britannia originally, they gave Canadair in Montreal the license to build on the original plans and modify them a bunch...musta been a humongous project...good article with what was involved at: http://www.geocities.com/cp107argus/CP107History.html This is a good site for info on this (in it's time) the best ASW aircraft in the world. -- -Gord. I kind of waited to see if anyone questioned my placing the B-36 on the list with it's pusher engines. Regards, Tex Back to top Gord Beaman Guest Posted: Sun Aug 28, 2005 2:23 am    Post subject: Re: Engine question "Tex Houston" <texhouston (AT) pcisys (DOT) netVVV> wrote: Quote: "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote in message news:ue62h19hevvk879icgla57g01s0fn3t4rh (AT) 4ax (DOT) com... No Tex, it was Brit. (and I caught the little jab! Ü) Actually it was a Bristol Britannia originally, they gave Canadair in Montreal the license to build on the original plans and modify them a bunch...musta been a humongous project...good article with what was involved at: http://www.geocities.com/cp107argus/CP107History.html This is a good site for info on this (in it's time) the best ASW aircraft in the world. -- -Gord. I kind of waited to see if anyone questioned my placing the B-36 on the list with it's pusher engines. Regards, Tex When I read that post I thought "I must answer that but then I thought "well, they likely 'did' have spinners to help smooth the airflow as it left the props going backwards...". This 'would' reduce turbulence (and drag) wouldn't it?... -- -Gord. (use gordon in email) Back to top Tex Houston Guest Posted: Sun Aug 28, 2005 2:35 am    Post subject: Re: Engine question "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote Quote: "Tex Houston" <texhouston (AT) pcisys (DOT) netVVV> wrote: "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote in message news:ue62h19hevvk879icgla57g01s0fn3t4rh (AT) 4ax (DOT) com... No Tex, it was Brit. (and I caught the little jab! Ü) Actually it was a Bristol Britannia originally, they gave Canadair in Montreal the license to build on the original plans and modify them a bunch...musta been a humongous project...good article with what was involved at: http://www.geocities.com/cp107argus/CP107History.html This is a good site for info on this (in it's time) the best ASW aircraft in the world. -- -Gord. I kind of waited to see if anyone questioned my placing the B-36 on the list with it's pusher engines. Regards, Tex When I read that post I thought "I must answer that but then I thought "well, they likely 'did' have spinners to help smooth the airflow as it left the props going backwards...". This 'would' reduce turbulence (and drag) wouldn't it?... -- -Gord. (use gordon in email) I don't know. I ended up including it just for that reason. I'm surprised I came up with that many examples in only one book. Tex Back to top Keith W Guest Posted: Sun Aug 28, 2005 7:55 am    Post subject: Re: Engine question "Tex Houston" <texhouston (AT) pcisys (DOT) netVVV> wrote Quote: "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote in message news:m512h1t1qlp012ibgtu1i33plnkgof3rkd (AT) 4ax (DOT) com... So did the Argus with which I'm very familiar too... -- -Gord. Gordon, Was the Canadair Argus an American aircraft? It had American engines Quote: Oops. Indeed Keith Back to top Gord Beaman Guest Posted: Mon Aug 29, 2005 12:14 am    Post subject: Re: Engine question "Keith W" <keithnospam (AT) kwillshaw (DOT) demon.co.uk> wrote: Quote: "Tex Houston" <texhouston (AT) pcisys (DOT) netVVV> wrote in message news:2dadnc2UlvzYlIzeRVn-rA (AT) pcisys (DOT) net... "Gord Beaman" <gord (AT) islandtelecom (DOT) com> wrote in message news:m512h1t1qlp012ibgtu1i33plnkgof3rkd (AT) 4ax (DOT) com... So did the Argus with which I'm very familiar too... -- -Gord. Gordon, Was the Canadair Argus an American aircraft? It had American engines Oops. Indeed Keith Yes indeed, Wright R-3350-EA-1's to be exact...the most advanced piston engine in the world...produced 3700 BHP...mister, when you got four of those in your left hand it doesn't take long to get up to 'rotate' on a 'touch and go'... -- -Gord. (use gordon in email) Back to top Mike Weeks Guest Posted: Mon Aug 29, 2005 2:57 am    Post subject: Re: Engine question Max Richter wrote: Quote: Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Here's an example of one aircraft's evolution regarding spinners -- and on-topic for the NG! <g> XSB2C-1 & prod. -1's had a spinner w/ a 3-blade prop. SB2C-3 w/ a 4-blade prop had no spinner. SB2C-4 w/ a 4-blade prop had a spinner. And finally the SB2C-5 had no spinner w/ it's 4-blade prop. Just by looking over various pubs of the naval a/c which came out of WWII (and those at the start) -- almost all had spinners at some point; some only in the X-version. But the F2A (FWIW) had the spinner up until the -3 version (which never saw front-line service.) It would seem no version of the F4U had spinners. The F8F had no spinner, yet at least one after-war modified Bearcat racer had a very larger spinner. Can't address what it means except to note that by the war's end, no front-line naval a/c had spinners. The other comments all seem logical, yet the SB2C evolution appears rather strange. MW Back to top Red Rider Guest Posted: Mon Aug 29, 2005 4:07 am    Post subject: Re: Engine question "Max Richter" <RichterMax (AT) t-online (DOT) de> wrote Quote: Hallo, i am wondering why American aircraftradialengines have no aerodynamical spinners.Airplanes with inlineengines like P51;P40;P38 and so on have aerodynamical optimized spinners. And German radialengines had spinners like the FW190.Zero´s and other Japanese aircraft had them. What is the reason why the wellbuild American aircraft had just a little hup on their propellers. Thank You and greetings Max Hummmmmm, a little before my time but from what I remember from talks with my grandfather (he was a NAP) and my dad (also a Naval aviator) both whom flew many different types of radial engine aircraft, I think that spinners may have disrupted the air flow. Pre-WWII the intake designs being used were classified. Developed they eventually gave almost a 10% performance improvement over the designs in use in the rest of the world at the time. The Jap "Zero" copied an earlier US intake design which added to its performance, but this design still didn't perform as good as later (early WWII) designs did. A 10% performance gained in aerodynamics and cooling, all due to the shape of the cowling was nothing to pass up. Many, many years have passed since those conversations with my grandfather and my father. I just wish I had paid more attention to what they said about their experiences. My grandfather flew for more than 25 years retiring in 1952 with 33 years in, and my father flew for 19 years before he passed in 1961. 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