1936 Cierva-FW and alternative helicopter history

[NOMISYRRUC]

The lack of a decent engine is another drawback, the available radials were low powered and needed modifications to work horizontally (oh how Wolseley might have saved the day?).

I think the Putnams book on Bristol aircraft said that Hafner wanted the Type 171 Sycamore to use the Aquila sleeve-valve engine, but it wasn't possible to restart production and that he wanted the Type 173 to use the Janus gas turbine engine, which had to be abandoned because the engine division didn't have the design capacity. Have I remembered correctly?

Have you any idea whether the Aquila would have made a half-decent helicopter engine?

 

[NOMISYRRUC]

...as you say Hafner ended up at AFEE, doing interesting but questionable work (who the hell really wants a controlled-crashing Valentine!?!).

The flippant answer might be "Someone who saw the glider-borne alternatives!"

The Wikipedia entry says the Rotachute was developed because at the time there was a shortage of silk for parachutes. Is that true? I ask the question because a few months ago I was stung rather badly by believing what I read on Wikipedia.

Do you know what the "method in the madness" that led to the Rotabuggy and Rotatank was? My guess is that the powers that be though they couldn't build gliders in the quantities required and they needed something else to make up the numbers.

Was the work he did at AFEE of any use when he went to Bristol and designed the Sycamore? If only to teach him how not to do it.

 

[Archibald]

Wait wait wait. Gimme a break. I know the freakkin' Soviets designed a biplane glider to hang a T-26 tank below. And I've heard of the rota-buggy. BUT - they wanted to autogyro a Valentine tank ???

 

[Archibald]

And I thought 1930's France "aircraft-catapults-on-Laffly-trucks-chassis" plans that started with Caudron Lucioles and ended with LeO-451 bombers, were nutty...

 

[NOMISYRRUC]

CFW-8 Matador

Was that inspired by this?

Airfix 1/24 Wallis WA-116 Agile Autogyro: “Little Nellie”

This kit was first released fifty years ago. It's a model of a real aircraft, the Wallis WA-116 Agile autogyro, designed by Ken Wallis and built in extremely limited numbers (five!) in 1962. It achieved fame because one aircraft, G-ARZB, was kitted out with some splendid yellow-and-silver livery...

oikofuge.com

I posted this link because I'm a member of the "Airfix Generation" and I suspect that many of the other British contributors are as well.

 

[Hood]

The lack of a decent engine is another drawback, the available radials were low powered and needed modifications to work horizontally (oh how Wolseley might have saved the day?).

I think the Putnams book on Bristol aircraft said that Hafner wanted the Type 171 Sycamore to use the Aquila sleeve-valve engine, but it wasn't possible to restart production and that he wanted the Type 173 to use the Janus gas turbine engine, which had to be abandoned because the engine division didn't have the design capacity. Have I remembered correctly?

Have you any idea whether the Aquila would have made a half-decent helicopter engine?

That would not surprise me. I've seen a plan drawing of the Westland WS-55 using a Bristol Perseus!

Britain had a distinct lack of low power radials. Cheetah is about the only other one. Britain during 1935-39 seemed to have little need of 400-600hp radials and consequently the Aquila wasn't really used, Wolseley pulled out, Alvis persevered but war intervened and everyone else used Cheetahs. So by 1945 there wasn't anything other than surplus stocks of Cheetahs with engine technology going way back to the late 20s. Britain had nothing in the Wasp class and for helicopters this was the sweet spot. If Alvis hadn't stuck the course and there had been no Leonides then either the choices would have been to part with Dollars for stock Wasps or develop a new engine.
We didn't really have a Cyclone clone either - hence Leonides Major which proved less than ideal for helicopters.

I suspect that Germany had the same problem, other than the Bramo series they didn't have much in the way of small radials either and BMW were not exactly forthcoming with Bramo production once they took over with the RLM screaming for more 801s.
The Russian's were reliant on the M-11 for their helicopters/gyros.
I would say that the US lead might have as much to do with having the right engines as it was about rotary aerodynamic knowledge.

It wasn't just the rotor blades and hinges and transmissions that had to be perfected, but you needed decent engines with high power/weight ratios to be able to carry anything useful. At least messing about with autorotation Hafner didn't need to worry about engine power!

 

[riggerrob]

I don't know Hafner's subsequent history in detail, but I'm doubtful that if the war had not intervened, Hafner's twisted-aerofoil fuselage producing counter-torque from rotor downwash would have been successful. The downwash velocity and mass-flow would be highly dependent on air temperature, engine speed, precipitation status and ground effect among other factors...and all of those require a rapid pilot capability to independently adjust counter-torque, which would not exist.

I would agree with this. Hafner was being highly optimistic about this layout and I think stability would be horrendous even assuming it didn't corkscrew itself into the ground.

As far as I know helicopter development in Britain was suspended for the first two-thirds of the war. E.g. Weir stopped on their own accord because they thought their facilities would better serve the war effort doing something else. Hafner was interned and then sent to work at the AFEE.

Cierva won't be interned as an enemy alien but his efforts could well be hampered by lack of Government support 1939-43 due to the UK's limited industrial resources being concentrated on projects that were thought to be more important.

Beaverbrook explicitly stopped all work on rotary-wing in his 1940 memo dropping everything but the six key types. Those strands were never picked up again, as you say Hafner ended up at AFEE, doing interesting but questionable work (who the hell really wants a controlled-crashing Valentine!?!).

Weir gave up, but they hadn't seen much return for their efforts thus far. The Sikorsky R-4 changed everything, the FAA wanted them for ASW but couldn't get them quick enough before the U-Boat menace was curbed by other methods (Cats, Libs and Woolworth carriers).
Even if we postulate a restart on helicopters in 1941, its doubtful prototypes would be in the air much before 1943, given the test flying programme needed, its 44 or early 45 before something is operational. The lack of a decent engine is another drawback, the available radials were low powered and needed modifications to work horizontally (oh how Wolseley might have saved the day?). That was another serious bottleneck until the Alvis Leonides was in production after the war and even then it took until the turboshaft (Gnomes = more licenced US tech) until we really had something decent.

Germany seems to have done about the best she could given the priorities and need and what was on hand.

If you really want to push this "what if" start with Kreigsmarine developments of autogyro kites and Flettner helicopters that could land on ship's decks. During the first few years of service, limit their use to mail, ambulance and gunnery spotting.
Secondly, get the Royal Navy interested in similar missions.
If 8 is the maximum number of troops that can be carried during WW2, then limit these young helicopters to landing naval gunnery officers and special squads of assault pioneers (see DFS glider use at Fort Eban Emal, Belgium).
You do not need to land an entire invasion force by helicopter or parachute, just a few handfuls of NGO and AP on key choke points (e.g. Pegasus Bridge).
Finally, you do not need to modify radial engines to mount horizontally. Sikorsky R-4 was one of the few helicopters to mount radials that way. Later S-55 and S-58 mounted their radials at 45 degrees, in the nose with a long drive shaft going up through the cockpit to the main transmission.
A fluidic clutch would greatly help to remove secondary and tertiary torsional vibrations created by piston engines. Look at the super-charger drive mechanism on Me.109. The Me. super-charger drive was essentially "dry" while producing low power at low altitudes, but as they climbed, they added more and more fluid to the drive clutch until it was "full" at the engine's operating ceiling. You could assign double-duties to clutch cooling pumps to vary the amount of fluid inside the clutch during start-up.

 

[Francisco Martínez Torres]

CFW-8 Matador

Was that inspired by this?

Airfix 1/24 Wallis WA-116 Agile Autogyro: “Little Nellie”

This kit was first released fifty years ago. It's a model of a real aircraft, the Wallis WA-116 Agile autogyro, designed by Ken Wallis and built in extremely limited numbers (five!) in 1962. It achieved fame because one aircraft, G-ARZB, was kitted out with some splendid yellow-and-silver livery...

oikofuge.com

I posted this link because I'm a member of the "Airfix Generation" and I suspect that many of the other British contributors are as well.

Well, not really like that

I already say that I was carried away by enthusiasm, my theory was to transfer the pair huey - cobra, troop transport and armed escort, to 1940. Assuming a development appropriate to the time, and of course as helicopters, not gyroplanes

with the names, well, I already say that the inspiration of the fictional attack helicopter is matador, because that is what the harrier is called in the Spanish army. For the Spanish, matador has a macho connotation. In my imagination it would be an XO-61 with 20mm Hispano cannons.

the CFW-47 is nothing more than a chinook, but in 1940, that's why the number 47.

 

[Archibald]

Helicopters really did sucked with piston engines. It took turbines to get them out of their misery. France tried to arm piston-engine Sikorskys in Algeria (in fact its experience there 1957-1962 found its way into the US Army early Vietnam era attack helicopter contraptions). The results weren't good at all. When they could takeoff in the very hot climate, those things vibrated so much, aiming was a major issue. Turbine was a much, much needed revolution.
Same for this machine in Indochina, 1951-54 (the irony) it suffered like hell.
https://fr.wikipedia.org/wiki/Hiller_UH-12_Raven

This well noted, I have to say I'd like to try and imagine an R-2800 or R-3350 or even R-4360 powered helicopter carrying a bunch of HS-404 guns plus some armor.

If the damn thing with a P-47 or B-29 or B-36 engine (!) can't lift a pair of guns and some armor plus just one pilot - then I give up. Also: give it a load of those Typhoon rockets that rained havoc on the Panzers in July 1944 in Normandy.

Or, if German LW: the Me-262's 30 mm gun and R4M rockets.

 

[Francisco Martínez Torres]

At least messing about with autorotation Hafner didn't need to worry about engine power!

That was the key, i think: at some point it became mandatory to motorize the rotor, instead of using it as a rotary wing, or gyroplane, and development continued in that way

the missing link is the XO-61, the point where the autogiro meets the helicopter. if they had continued on that path, they could indeed have grown in weight, engine power and load capacity much earlier: the gyrodine is the evolution.

But the main target was stationary flight, including vertical take on, and that changed the future.

 

[Michel Van]

That's interesting though, because due to your screen being Michel Van rather than Michel Von I presumed that you were Dutch not German.

Half german, half Dutch with Belgium roots ( the dark part of the Family... )
i speak English, German, Dutch and French, the standard survival package for Belgium...

Beaverbrook explicitly stopped all work on rotary-wing in his 1940 memo dropping everything but the six key types.

What if Avro manage to make operational version of Cierva C.30 the Avro 671 Rota more successful ?
And Beaverbrook took the autogyro into his 1940 memo ?
this could led to new aircrafts, even that Farirey start earlier there Gyrodyne helicopter program...

 

[JWilly]

Foche said that with the help of Juan de la Cierva he could have developed the helicopter much earlier.

Let's just say that Germans were much better known for bombastic claims, than for doing anything practical.

OK, but the statement was in regard to helicopters, and the OTL Fa 223 was the heaviest-payload, most-practically-useful cargo/troop helicopter during most of WWII by a considerable margin. History suggests that it would have been used in significant numbers in the latter part of the war if Allied bombing hadn't repeatedly destroyed its production facilities.

 

[JWilly]

In 1940, Germany launches an airborne attack on England with 1,000 pairs of attack/transport helicopters,

...Losing nearly half of them immediately from RAF fighters and crashes, and landing about 2000 troops without heavy weapons, which are mostly apprehended by Home Defense with ease.

Regarding losses during an invasion: certainly it would be a bad idea to fly slow helicopters into contested airspace. But why would a helicopter assault not be part of a larger-scale effort involving an attempt to achieve at least local air superiority, with seaborne landings plus parachute drops in other locales...? We all know in hindsight that the Sealion plans were poorly conceived, but contemporaneously the British regarded those plans and the underlying capabilities as realistic, and worried that the Germans might well get troops ashore. The proposed ATL, as I understood, was to explore the addition of a helicopter-borne-troops capability to that 1940-contemporaneous it-might-work perspective.

Regarding "landing (...) troops without heavy weapons": for a helicopter with a payload approaching 2000 pounds, i.e. as functional as a 1942 operational pre-production Fa 223 or the 1940 prototype Fa 223, 8 WWII-average-weight troops carrying only summer combat gear, with support gear and materials in subsequent payloads, could be equipped with an LMG, several hundred rounds in canisters, four rifles, two SMGs, and a large number of hand and rifle grenades, plus demolition materials. Or, six men, three 50mm mortars and two hundred rounds in lightweight packaging in paratroop-type wheeled canisters. Or, six men, two Solothurn S18/100 AT guns on wheeled glider-troop carriages and a hundred rounds. I would think that would be a plausible 1940 assault loadout. Of course, any light-infantry frontal assault on a prepared position would be difficult. But, that's always the case for paratroops, yet historically they've sometimes been effective because of their potential for surprise and arrival at unexpected locations.

 

[JWilly]

The lack of a decent engine is another drawback, the available radials were low powered and needed modifications to work horizontally (oh how Wolseley might have saved the day?).

I think the Putnams book on Bristol aircraft said that Hafner wanted the Type 171 Sycamore to use the Aquila sleeve-valve engine, but it wasn't possible to restart production and that he wanted the Type 173 to use the Janus gas turbine engine, which had to be abandoned because the engine division didn't have the design capacity. Have I remembered correctly?

Have you any idea whether the Aquila would have made a half-decent helicopter engine?

That would not surprise me. I've seen a plan drawing of the Westland WS-55 using a Bristol Perseus!

Britain had a distinct lack of low power radials. Cheetah is about the only other one. Britain during 1935-39 seemed to have little need of 400-600hp radials and consequently the Aquila wasn't really used, Wolseley pulled out, Alvis persevered but war intervened and everyone else used Cheetahs. So by 1945 there wasn't anything other than surplus stocks of Cheetahs with engine technology going way back to the late 20s. Britain had nothing in the Wasp class and for helicopters this was the sweet spot. If Alvis hadn't stuck the course and there had been no Leonides then either the choices would have been to part with Dollars for stock Wasps or develop a new engine.
We didn't really have a Cyclone clone either - hence Leonides Major which proved less than ideal for helicopters.

I suspect that Germany had the same problem, other than the Bramo series they didn't have much in the way of small radials either and BMW were not exactly forthcoming with Bramo production once they took over with the RLM screaming for more 801s.
The Russian's were reliant on the M-11 for their helicopters/gyros.
I would say that the US lead might have as much to do with having the right engines as it was about rotary aerodynamic knowledge.

It wasn't just the rotor blades and hinges and transmissions that had to be perfected, but you needed decent engines with high power/weight ratios to be able to carry anything useful. At least messing about with autorotation Hafner didn't need to worry about engine power!

The Bramos Fafnir engine series produced almost 1100 hp for the Fa 223 with, eventually, good reliability. It was a licensed copy of the Bristol Jupiter, a late-WWI 9-cylinder radial that was substantially improved through the 1920s and 30s.

In addition to the German version, the Jupiter design also was licensed and manufactured by the Soviet Union, Poland, Italy (two companies), France, Belgium, Czechoslovakia, Yugoslavia and Japan.

Part of the problem with helicopter development in Allied countries was their seat-of-the-pants guesstimate that "400-600 hp" engines should be sufficient. This limited them from the beginning to very lightweight structures and very small payloads.

 

[Dilandu]

Regarding losses during an invasion: certainly it would be a bad idea to fly slow helicopters into contested airspace. But why would a helicopter assault not be part of a larger-scale effort involving an attempt to achieve at least local air superiority, with seaborne landings plus parachute drops in other locales...?

Because Germany never have resources for that. Specifically:

involving an attempt to achieve at least local air superiority

Impossible due to Chain Home system, which gave British crucial advantage in airspace control & coordination.

with seaborne landings

Impossible due to Royal Navy presence, mines, coastal batteries, ect.

plus parachute drops in other locales...?

Excuse me, but if Germany build a thousand of helicopters, it would not have resources to build transport planes. Either - or.

1942 operational pre-production Fa 223 or the 1940 prototype Fa 223, 8 WWII-average-weight troops carrying only summer combat gear, with support gear and materials in subsequent payloads, could be equipped with an LMG, several hundred rounds in canisters, four rifles, two SMGs, and a large number of hand and rifle grenades, plus demolition materials.

Fa 223 could carry only four peoples inside. The eight troops was transported on EXTERNAL carriage.

And producing a thousand of Fa 223 would require more than a thousand of Bramo 323 engines. Which is about 20% of its total production from 1936 to 1944 (5500 produced in total). Such effort would cripple the Fw. 200 and Do.17 fleets, not to mention seriously affect other programs.

But, that's always the case for paratroops, yet historically they've sometimes been effective because of their potential for surprise and arrival at unexpected locations.

If Germany would put so much efforts into transport helicopters, it's kinda be expected.

 

[riggerrob]

...as you say Hafner ended up at AFEE, doing interesting but questionable work (who the hell really wants a controlled-crashing Valentine? ...

The Wikipedia entry says the Rotachute was developed because at the time there was a shortage of silk for parachutes. Is that true?

WALLIES suffered silk shortages after Japan conquered most of the silk-growing regions of Asia. That left Britain with only silk grown in India.
During WW2, the Canadian and American parachute industries converted to synthetic nylon made from petro-chemicals. Nylon is twice as strong as silk, does not suffer from mold or insects, etc.
Scaling parachutes up to large enough to land vehicles softly was a huge engineering obstacle really only perfected after WW2.

Haffner's Roto-Buggy was an early attempt at delivering light-weight Jeeps. Remember that Jeeps were only invented during WW2. Early attempts at para-dropping Jeeps proved disastrous. When RAF Halifax bombers dropped Jeeps to the mischievious SAS in the Massive Central of France during the summer of 1944, more than half of the Jeeps were wrecked. Part of the problem was Jeeps tumbling as they fell from Halifax and the other problem was building huge cargo chutes that were reliable.
Valentine was the best British light tank of WW2, but it weighed 16 long tons.
Tetrach weighed more than 8 tons.
Harry Hopkins tank weighed more than 9.5 tons.
... all too heavy to move by bomber or most assault gliders.
Even these purpose-built airborne, light tanks were too heavy to be delivered by parachutes. Only the huge British Hamilcar assault glider could deliver the specialized light tanks and it needed a Halifax tow-plane!
Too bad that their 2 -pounder (about 37mm) guns could only penetrate early war tanks and were obsolete by 1941. Tetrach and Harry Hopkins saw only limited combat during WW2.

Soviet/Ukrainian Oleg Antonov's attempt at adding biplane wings to a lightened T-60 light tank barely survived one test flight.

It was not until the 1950s and 1960s that Americans and Soviets learned how to para-drop light armor. Americans learned how to LAPES heavy vehicles (see Sheridan light tank) from a bare meter above a smooth field.
Soviets developed a combination of parachutes and retro-rockets to drop specialized light AFVs. Only the USSR seems to have continued to refine light AFVs specifically for paratroopers, but even the latest Russian para-droppable AFVs have anti-tank missiles capable of defeating main battle tanks. Their armor will barely stop heavy machineguns (12.5mm).

Rob Warner FAA Master Parachute Rigger

 

[NOMISYRRUC]

In 1940, Germany launches an airborne attack on England with 1,000 pairs of attack/transport helicopters,

...Losing nearly half of them immediately from RAF fighters and crashes, and landing about 2000 troops without heavy weapons, which are mostly apprehended by Home Defense with ease.

Their slow speed might be their best defence against Hurricanes and Spitfires.

@Francisco Martínez Torres suggested that the transport helicopter be similar to the Chinook which according to its entry in my copy of "Aircraft of the Royal Air Force since 1918" had a maximum speed of 180mph and a cruising speed of 160mph. They might be too slow to be intercepted. As I understand being too slow to intercept (along with their manoeuvrability) was the the means of defence against fighters employed by "grasshopper" light aircraft like the British Taylorcraft Auster.

When I was pouring scorn on the idea I though of suggesting that they'd give the nine squadrons of Westland Lysanders in No. 22 (Army Co-operation) Group something to do as (according to the same source) they had maximum speed of 219mph and two forward firing 0.303in machine guns. The RAF had a lot of last generation biplanes like the Fury, Demon & Gauntlet in the training schools which might have the right speed and right manoeuvrability for the job.