Weather limitations in carrier aviation in the interwar and WWII eras

[EwenS]

Nobody has yet mentioned Ranger's six funnels (there is a 1942 photograph at The Transitional Carriers: USS Ranger CV-4 and USS Wasp CV-7). They could be folded outwards to assist with flight operations but, I suspect, this may have reduced Ranger's speed.

Why do you believe that?

All part of the initial plan to build her as a flush decked carrier. 6 boilers, 3 each side of the centreline and, unusually, placed aft of the turbines. 6 uptakes, one for each boiler. The arrangement still allowed them to emit smoke when horizontal. Note the 'S' bend in the uptake between the exit from the boiler room and the folding upper part. Not so much a "fold" as a rotation around a "collar".

And with them folded down. Note how low the "fold" was.

 

[EwenS]

Ranger's flight deck was ~710ft* long vs ~530ft for Furious and ~580ft for Glorious and Courageous. We know from it's operational use in the USN that SBD-3s ranged forward, even on Yorktown class carriers, which could easily exceed 30 knots, had to reduce bomb loads to 500lbs to safely TO in light winds, as per Midway on 4 June 1942. The RN carriers would have to reduce the number of aircraft in the range and reduce the bomb and/fuel load during mission planning to safely TO, especially as wind over deck was variable, and they couldn't afford to have flight deck ops stalled if the winds died down.

Amusing that variable winds only seem to affect the RN in your view.

Typically, US carriers used only the aft half of their flight deck to range a strike. That meant the SBD at the front of the range would only carry 500lb bombs. In that respect Ranger doesn't seem to have been different from other USN carriers. During Operation Leader in Oct 1943, the first 6 were restricted to 500lb-ers.

For Leader Ranger launched

Strike 1 - 20 SBD + 8 Wildcat
Strike 2 (launched 30 mins later) - 10 TBF & 6 Wildcats.

AIUI, her aircraft complement was 27 SBD-5, 18 TBF-1 & 27 F4F-4. The low natural wind speed during that operation is commented on by various authors.

The RN simply accepted their deck limitations in the early part of the war. For Taranto, with the Swordfish needing overload tanks, the range had to be limited to 12 in the first launch and would have been 12 in the second, but for losing 3 Swordfish en route.

As the war went on, the aft round downs on the armoured carriers was flattened out, so increasing the useable deck space and allowing more aircraft to be ranged for each strike.

The long and short of all this is that the Skua was the superior aircraft to the SBD-3 (which didn't exist in 1939/40) as it had a superior power to weight ratio and folding wings and had been designed to suit the operational characteristics of RN carriers. Similarly the Albacore, which was delayed into carrier service until about the time that the SBD-3 arrived, had better STOL characteristics and a much larger bomb load. Unlike the USN and IJN, the RN's fleet carriers were conversions of fully built battlecruisers (if we can call F-G-C that) and they suffered in comparison to early USN fleet carriers that were converted during building or purpose built, such as Ranger.

By 1939 F-G-C max service speed was about 28 knots and they typically could only range ~9 to 12 aircraft at a time.

*Friedman in US Aircraft Carriers, states ~750ft by 1943.

The first production Albacore rolled off the production line in Sept 1939 with series production starting in Jan 1940. The first Albacore squadron formed on 15 March 1940 and the next on 15 June 1940. Both went aboard Formidable in Nov 1940, shortly after she completed. By that time other squadrons were also receiving Albacores.

Douglas produced 57 SBD-1 from June 1940 that went to the USMC. That was followed by 87 SBD-2 for USN squadrons. Production of the SBD-3 didn't begin until March1941 and it didn't fully succeed earlier types (earlier SBD variants and other dive bomber types - biplane SBC-4 & SB2A Vindicators) until mid 1942.

 

[cherry blossom]

Why do you believe that?

I said suspect because I assumed that the vertical position had to have some advantage or why fit it. However, on reflection it might simply be better in heavy seas.

The effects of having funnels on both sides will surely create disturbed air on both sides and make landing on Ranger similar to landing on Akagi or Hiryu. Thus it may not be ideal for the curved approach developed for the F4U.

 

[Thumpalumpacus]

I said suspect because I assumed that the vertical position had to have some advantage or why fit it. However, on reflection it might simply be better in heavy seas.

It was to get the ship's exhaust away from the aircraft's final approach.

The effects of having funnels on both sides will surely create disturbed air on both sides and make landing on Ranger similar to landing on Akagi or Hiryu. Thus it may not be ideal for the curved approach developed for the F4U.

There's no way around disturbing the air over the aft or in the final approach glideslope.

But I doubt very much that the wind resistance was a factor in Ranger's lower speed. 53,000 SHP to push 14,500 tons through the water at ~ 29.5 kts. Compare that to Wasp,
70,000 SHP to push 14,700 tons at, again, about 29.5 kts.

 

[Shortround6]

But I doubt very much that the wind resistance was a factor in Ranger's lower speed. 53,000 SHP to push 14,500 tons through the water at ~ 29.5 kts. Compare that to Wasp,
70,000 SHP to push 14,700 tons at, again, about 29.5 kts.

Any ship designers depending on lower wind resistance from the funnels to make speed has been smoking well used sneakers in his pipe.

The very common "fix" for a slow ship was to extend to funnels 10-15 ft for more draft to make more power.

 

[z42]

I said suspect because I assumed that the vertical position had to have some advantage or why fit it. However, on reflection it might simply be better in heavy seas.

Funnels have two functions. The main is to route exhaust away from the deck and superstructure of the ship. Secondly a longer funnel creates more draft increasing the power of the boilers; though this wasn't that important after the introduction of forced induction.

As for the Ranger funnel arrangement, my guess they wanted the ability to direct the exhaust away from the flight deck when conducting flight ops, thus having the funnels in the horizontal position. But when just steaming along in a crosswind that position would have half of the exhaust pouring out along the deck, hence the ability to put the funnels in the vertical position. Might also be more convenient when sitting in a harbor.

And yes, in really heavy seas you'd want the funnels in the vertical position as well, lest they gulp some seawater.

I don't think speed has anything to do with it. I don't think the aerodynamic drag of the ship would noticeably differ depending on the funnel position.

 

[RCAFson]

Amusing that variable winds only seem to affect the RN in your view.

Typically, US carriers used only the aft half of their flight deck to range a strike. That meant the SBD at the front of the range would only carry 500lb bombs. In that respect Ranger doesn't seem to have been different from other USN carriers. During Operation Leader in Oct 1943, the first 6 were restricted to 500lb-ers.

For Leader Ranger launched

Strike 1 - 20 SBD + 8 Wildcat
Strike 2 (launched 30 mins later) - 10 TBF & 6 Wildcats.

AIUI, her aircraft complement was 27 SBD-5, 18 TBF-1 & 27 F4F-4. The low natural wind speed during that operation is commented on by various authors.

The RN simply accepted their deck limitations in the early part of the war. For Taranto, with the Swordfish needing overload tanks, the range had to be limited to 12 in the first launch and would have been 12 in the second, but for losing 3 Swordfish en route.

As the war went on, the aft round downs on the armoured carriers was flattened out, so increasing the useable deck space and allowing more aircraft to be ranged for each strike.



The first production Albacore rolled off the production line in Sept 1939 with series production starting in Jan 1940. The first Albacore squadron formed on 15 March 1940 and the next on 15 June 1940. Both went aboard Formidable in Nov 1940, shortly after she completed. By that time other squadrons were also receiving Albacores.

Douglas produced 57 SBD-1 from June 1940 that went to the USMC. That was followed by 87 SBD-2 for USN squadrons. Production of the SBD-3 didn't begin until March1941 and it didn't fully succeed earlier types (earlier SBD variants and other dive bomber types - biplane SBC-4 & SB2A Vindicators) until mid 1942.

I never stated or implied that variable winds only affected FAA carriers (in fact, as I alluded to, it was an issue for the USN at Midway on 4 June 1942), but the combination of slower speeds and much shorter flight decks ensured that FAA aircraft had to have good STOL characteristics. The USN used as much flight deck as was needed to ensure safe TO for the forward aircraft. The exact timeline of the Albacore carrier service entry isn't that critical, but what was critical was it's STOL performance and that's why the FAA chose it, and when we look at the SBD we can see that it was not well suited for use on any of the FAA's fleet carriers, in preference to existing FAA aircraft.