# Spinner



## gottschs (Nov 18, 2020)

Anyone know why some aircraft in WWII had spinners on their propeller hub yet some didn't. The P-51/P-40/P-39/BF-109/FW-190/Japanese aircraft did yet the P-47,P-36 & none of the Navy aircraft did? Was it simply the radial vs. inline engines sizes that provided the streamlining and efficiency?

Thanks in advance for any insights.


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## warbird51 (Nov 18, 2020)

gottschs said:


> Anyone know why some aircraft in WWII had spinners on their propeller hub yet some didn't. The P-51/P-40/P-36/P-39/BF-109/FW-190/Japanese aircraft did yet the P-47 & none of the Navy aircraft did? Was it simply the radial vs. inline engines sizes that provided the streamlining and efficiency?
> 
> Thanks in advance for any insights.



The Navy didn’t use spinners as in their opinion, the maintenance required outweighed the improved drag performance that was obtained.


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## PFVA63 (Nov 18, 2020)

Hi,
I believe that Warbirds is correct. In addition to maintenance issues there is also the fact that they were added weight as well.

To help complete the picture though, it should be noted that not all USN Radial engine planes did not have spinners, as the early F2A-1 and F2A-2 planes did have spinners as well as some SB2C variants. Additionally in the UK while the merlin inline engine Hurricane and Spitfire fighters had spinners, the Merlin engined Fairy Battle did not for example.

F2A-1, F2A-2, & F2A-3












SB2C









Hurricane, Spitfire, & Battle


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## warbird51 (Nov 18, 2020)

PFVA63 said:


> Hi,
> I believe that Warbirds is correct. In addition to maintenance issues there is also the fact that they were added weight as well.
> 
> To help complete the picture though, it should be noted that not all USN Radial engine planes did not have spinners, as the early F2A-1 and F2A-2 planes did have spinners as well as some SB2C variants. Additionally in the UK while the merlin inline engine Hurricane and Spitfire fighters had spinners, the Merlin engined Fairy Battle did not for example.
> ...


Most Navy prototypes had spinners, but when they entered fleet use, they were deleted. There may be an exception out there, but everything I’ve read, the Navy decided against them


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## pbehn (Nov 19, 2020)

The spinner is there to smooth airflow over the hub, not all props worked the same way and some had more "gubbins" in the hub than others. For water cooled designs there is an obvious advantage for having the hub/spinner blend as smoothly as possible with the cowling. For air cooled designs this isn't as clear a choice because any spinner just changes the airflow into the engine. Later designs like the Sea Fury have a big spinner and a tight cowling such that I thought for years as a kid it was water cooled. It obviously worked although I don't know how long it could be kept on deck with the engine running without over heating.

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## PFVA63 (Nov 19, 2020)

warbird51 said:


> Most Navy prototypes had spinners, but when they entered fleet use, they were deleted. There may be an exception out there, but everything I’ve read, the Navy decided against them



Hi,

Although I do believe that they were eventually removed from the F2A-3's I believe that there are many photos of operational F2A-1 & 2's with spinners as well as SB2C's.

Regards

Pat






Curtiss SB2C-5 Helldiver


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## chuter (Nov 21, 2020)

Spinners on full cowled radials only really work if the entire engine compartment is reasonably streamlined with a gearbox cover behind the spinner and minimal exposed structure inside the cowling. The cowl flaps control the amount of air that enters the cowling (duh) and with them closed (not actually "closed" as in sealed but the normal flight position) a lot of air pressure builds up in front of the engine forming a "pressure dome" that forces a lot of the air around the cowling, so, around the spinner. So on a radial, a spinner is basically just part of the overall cooling drag reduction solution that doesn't really accomplish much without the rest of the drag reduction measures inside the cowling (like what you might see on a racer). That extra sheetmetal can be a maintenance nightmare and was likely deemed not worth it in service.

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## Admiral Beez (Nov 21, 2020)

PFVA63 said:


> Hi,
> 
> Although I do believe that they were eventually removed from the F2A-3's I believe that there are many photos of operational F2A-1 & 2's with spinners as well as SB2C's.
> 
> ...


This Wildcat just doesn’t look right.


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## BiffF15 (Nov 21, 2020)

Admiral Beez said:


> This Wildcat just doesn’t look right.
> 
> View attachment 602567



I like it. I looked around for a picture of an F8F with a spinner but couldn't find one (someone used to fly one around). Also, La Patronis, and F7F has spinners on it and I think it looks good.

Cheers,
Biff

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## PFVA63 (Nov 22, 2020)

Hi,
I think these might be some.
Pat

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## GregP (Nov 22, 2020)

The spinner on Rare Bear (below):






Came off of a Bristol freighter.

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## GrumpyOldCrewChief (Nov 22, 2020)

The efforts that went into RareBear for its racing career would have been impossible to support in an operational Naval environment. Not even going into the engine alterations / substitutions area...
... an R-3350? In 1945? On a carrier?


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## GregP (Nov 22, 2020)

I didn't and don't recommend any Reno racer as a military aircraft. They have no armament, no range, and have VERY temperamental systems and powerplants.

Rare Bear, for instance, has a compressed air system for the gear, and it only works maybe twice before needing to be charged up. But ... it DOES have a neat spinner.

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## jgreiner (Nov 28, 2020)

As Pbehn stated above, I believe it was mostly air cooled vs. water/liquid cooled engines. Prime example: P-47 vs. P-51. Huge air cooled radial on the '47 and the water cooled Merlin on the Mustang. Of course the Mustang had a cold air duct below the fuselage (and small one in front, below the spinner, but for an air cooled engine, smack dab in front and getting air on that big radial was very important. Note the bottom 1/4 or so of the P-47 had a separate air duct running to the supercharger.


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## MiTasol (Nov 28, 2020)

pbehn said:


> The spinner is there to smooth airflow over the hub, not all props worked the same way and some had more "gubbins" in the hub than others. For water cooled designs there is an obvious advantage for having the hub/spinner blend as smoothly as possible with the cowling. For air cooled designs this isn't as clear a choice because any spinner just changes the airflow into the engine. Later designs like the Sea Fury have a big spinner and a tight cowling such that I thought for years as a kid it was water cooled. It obviously worked although I don't know how long it could be kept on deck with the engine running without over heating.


The Sea Fury and many others had great big fans incorporated in the rear of the spinner to force airflow through the engine.

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## jgreiner (Nov 28, 2020)

MiTasol said:


> The Sea Fury and many others had great big fans incorporated in the rear of the spinner to force airflow through the engine.



Yup. So did the Fw-190, Ju-88, etc. I was just saying I believe it was *mostly* because of air vs. water cooled engines. Not exclusively.


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