British Rigid Airships in World War One
I dug this out of one of my Royal Navy in the Great War - Money No Object essays.
In the real world the British developed rigid airships spasmodically with the result that satisfactory machines did not appear until after the war was over.
HMA No 1, "Mayfly" was ordered from Vickers in 1909 and completed in 1911. However, she was written off in an accident before she flew. The next rigid airships were the R.9 ordered in June 1913 and 2 sisters ordered in the 1914-15 Navy Estimates. They were all were cancelled when World War One broke out because it was thought that the war would be over before they could be completed. However R.9 was reinstated later on and delivered at the end of 1916.
10 R.23 class were ordered in April 1916 and the first 4 were completed in 1917. In common with Mayfly and R.9 they provided vital experience that was read into succeeding designs and were useful for training, but could not be used operationally because they didn't produce enough "disposable lift". Therefore the last 6 were re-ordered as the R.23X class. This was the first operationally useful design and could have been mass produced. However, only 2 were completed. The captured German airship L-33 was better and the R.23X programme was cancelled in favour of new designs influenced by the L-33. These airships were much better than the R.23X class, but none of them were completed until 1919.
Vickers wanted to build “Mayfly” with a fully streamlined hull but the idea was rejected by the Admiralty owing to constructional difficulties and she was built with a "Zeppelin" shaped hull. The R.80 begun at the end of 1917 and flown in the middle of 1920, was the first airship to be built with this type of hull and in terms of technology she was the best airship of her day. Vickers also gave the R.100 airship built for the Burney Scheme this type of hull.
In this version of history the point of departure is the report of the Esher Committee, which recommended that the Admiralty should order two rigid airships for evaluation instead of one.
The Admiralty decided that the first should be of the conventional Zeppelin type (i.e. the Mayfly) and the latter of the fully-streamlined type (effectively R.80 with less powerful engines). Before they were completed it was decided to order a pair of R.9 type airships (i.e. enlarged Mayflies) in the 1910-11 Navy Estimates and four R.23 type airships (i.e. enlarged R.9s) in the 1911-12 Navy Estimates.
Mayfly was still written off in an accident before she could be flown. However, H.M.A. No. 2 (the streamlined prototype) was completed in the first quarter of 1912. It was faster and produced more "disposable lift" than the R.9s (which were completed in the second half of 1912) in spite of being smaller. This led to quartets of R.80 class airships being ordered in the 1912-13, 1913-14 and 1914-15 Estimates. The R.23 class came into service in 1913 and the first two R.80 class were in service when the Great War broke out. That is the British had completed 10 rigid airships by August 1914 and 9 of them were in RNAS service at the outbreak of war.
By comparison the Germans had flown 33 rigid airships (27 Zeppelin, 4 Gross Basenach and 2 Schutte-Lanz) by August 1914 and 13 were in service. The German Navy had 8, the German army had one and the airline, DELAG, had 3 (of which 2 went to the army and the other to the navy).
This head start allowed the Royal Navy to build up a large force of rigid airships during the Great War in place of the non-rigid airship force that was created in the real world.
Rigid airships were more expensive to build and needed larger crews than the blimps, but the extra cost was more than outweighed by their operational advantages, which saved money in other areas.
Rigid airships were better than blimps because they had heavier armaments, were faster and could spend longer on patrol. Observers in rigid airships did not tire so easily as those in the open cockpits of the Sea Scout and Coastal blimps. Thus a rigid airship was more likely to spot a U-boat and trials conducted in the real world showed that they were no more likely to be spotted by U-boats than a blimp.
The proportion of sightings to attacks by blimps was low because their low speed meant the U-boats had time to submerge before they could attack. However, this was less of a problem with the rigids because they were faster and they were armed with a 4” gun. The guns never sank a U-boat but kept many on the surface until the airship got within bombing range or close enough for it to shadow the submarine until surface forces arrived.
In the real world the RNAS could not provide enough sheds for its blimps. The problem was solved by housing some of them in quarries and forest clearings. Trials conducted with R.9 and the R.23 class showed that this was also feasible with rigid airships.