Heliopters autogiros for the ww2: underused, or not worth it?

[FLYBOYJ]

Great information guys!
Shortround has nailed just about everything that could be said about recip engine liabilities on early helicopters but there other things to be considered (includes autogyros too);

Rotor blades – some were made from wood others were wood framed covered with fabric, definite reliability issues due to viabration and environmental operating conditions (you could never operate these early rotor systems in icing conditions and I know moisture content played havoc on these blades.

Rotor masts and effective controls – although the systems basically worked, they were still crude and needed time to evolve to become effective. AFAIK early helicopters had crude rotor dampening devices and could be very tricky to fly.

Bearings – something was simple as bearings had to be developed to deal with high speeds, stresses and sometimes temperature variations that fixed wing aircraft never had to deal with. Kaman Helicopters took this so seriously they have a whole manufacturing division that manufactures only bearings and have expanded out of the rotorcraft industry.

These are just a few things I can think of off the top of my head. I do know the Fi-282 was probably the most reliable early helicopter.
I helped restore a 1938 Kellett K-2 about 12 years ago. It was a non-flying static model and just looking at it scared me!

 

[FLYBOYJ]

Lycoming T53 turboshaft
860 hp.
688 lbs dry weight.
What's so special about the HH-43 turboshaft engine?
The proposed Fi-339 helicopter was powered by a BMW-132 engine.
947 hp (BMW 132J).
1,157 lbs dry weight.
Heavier then an early model turboshaft but I suspect fuel economy was better. So there might not be much difference in useful payload (after subtracting fuel weight).

Weight, torque and the size of the powerplant when you consider the criticality of weight and balance on a helicopter

 

[FLYBOYJ]

Could someone make capability estimates for a helicopter powered with, say, R-1820?

The Piasecki H-21 was powered by one. Piasecki H-21 - Wikipedia, the free encyclopedia

 

[GrauGeist]

The Luftwaffe produced a number of different helos...the Fl282 (Flettner Kolibri) being pretty successful for a number of roles.

The reliable Sh14 radial produced 160 hp and gave the Kolibri a max speed of 93 mph.

 

[tyrodtom]

The Sikorsky S-58, or H-34 was also powered by the R-1820.

 

[Shortround6]

Lycoming T53 turboshaft
860 hp.
688 lbs dry weight.
What's so special about the HH-43 turboshaft engine?

The proposed Fi-339 helicopter was powered by a BMW-132 engine.
947 hp (BMW 132J).
1,157 lbs dry weight.
Heavier then an early model turboshaft but I suspect fuel economy was better. So there might not be much difference in useful payload (after subtracting fuel weight).

Where did you get the weight of the T53? Wiki?

The weights of the different T53 models varied considerably. For instance the differences between the L-11 and L-13 include a 4 stage power turbine instead of a 2 stage turbine, variable incidence inlet guide vanes instead of fixed and the first two compressor stages redesigned. And the L-13 only weighed 549lbs. The 860hp L-1 version weighed 480lbs.

Weights are from "Jane's all the worlds aircraft" and "Aircraft engines of the world" by Wilkinson

BTW, weight of 240hp Argus AS 10 inverted V-8 air-cooled engine---470lbs
weight of 160 hp Bramo Sh 14A 7 cylinder radial air cooled engine---297lbs
weight of 280hp Hirth HM 508D inverted V-8 air-cooled engine---458lbs
Weight of 450hp Argus As 410 inverted V-12 air-cooled engine---694lbs.

 

[wuzak]

Here's Wiki's specs for the T53

Specifications (T53-L-701)

General characteristics
Type: Turboshaft
Length: 58.4in 1483mm
Diameter: 23in 584mm
Dry weight: 688 lb (312kg)

Components
Compressor: 5-stage axial compressor and 1-stage centrifugal compressor

Performance
Maximum power output: 1,400 shp (1,044 kW)
Overall pressure ratio: (7.2 T53-L-32B[1] )


And the BMW 132

Specifications (BMW 132 Dc)

Data from [1]

General characteristics
Type: Nine-cylinder single-row supercharged air-cooled radial engine
Bore: 155.6 mm (6 1⁄8 in)
Stroke: 161.9 mm (6 3⁄8 in)
Displacement: 27.7 l (1,690 in³)
Length: 1,411 mm (55.55 in)
Diameter: 1,380 mm (54.33 in)
Dry weight: 525 kg (1,157 lb)

Components
Valvetrain: Two overhead valves per cylinder
Supercharger: Single-speed centrifugal type supercharger
Fuel system: Hobson carburetor
Fuel type: 87 octane rating gasoline
Cooling system: Air-cooled
Reduction gear: Farman epicyclic gearing, 1.61:1

Performance
Power output:
589 kW (789 hp) for takeoff
581 kW (779 hp) at 2,290 rpm at 2,900 m (9,515 ft)

Specific power: 21.26 kW/l (0.47 hp/in³)
Compression ratio: 6.5:1
Specific fuel consumption: 322 g/(kW•h) (0.53 lb/(hp•h))
Oil consumption: 8-11 g/(kW•h) (0.21-0.28 oz/(hp•h))
Power-to-weight ratio: 1.12 kW/kg (0.68 hp/lb)


Note that the T53 is less than half the diameter of the BMW 132 and only two or three inches longer. Weight is 60% of the BMW for more then twice the power.

Also note that the BMW could only have max power for short periods.

 

[Shortround6]

The version of the T53 listed in Wiki was never used in the Kamen helicopter.


the Version used in the Kamen was.

General characteristics
Type: Turboshaft
Length: 47.6 1209mm
Diameter: 23in 584mm
Dry weight: 480 lb (312kg)

Components
Compressor: 5-stage axial compressor and 1-stage centrifugal compressor

Performance
Maximum power output: 860shp
Normal power output: 770shp
Overall pressure ratio: (6.0 T53-L-1A )
Fuel consumption, normal.. 0.76lb/shp/hr

BTW, the L-3 version was a turbo prop and was good for 960shp for 530lbs including reduction gear (12.4:1) and propeller shaft.

To be fair the Piston engines can remove the reduction gear boxes (if fitted) and propshafts to try to adjust their weight to the shaft turbines. The fuel consumption of the turbines is much higher but is off set to some extent by the light weight.

Helicopter ranges can be an illusion is some cases. The Sikorsky S-55 with the P&W R-1340 Radial was supposed to be good for 440miles (with reserve) on 190 US gallons of fuel. It had a disposable load of 2050lbs of which almost 1140lbs was fuel. It was supposed to carry 8-10 men in the cabin and a crew of two. With full fuel you have about 900lbs or six 150lb men. with Twelve 160lb men on board you can carry 130lbs of fuel or about 21 gallons. Range is now?????

If Mr. Bender really wants to compare Piston engines to gas turbines perhaps he should compare the BMW 132 (in what-ever form) to the Lycoming T-55 or General Electric T64. 1950s or early 60s versions of the engines did put out less power than what is listed in Wiki.

 

[cimmex]

There were no turboshaft engines during WWII.
cimmex

 

[Shortround6]

There were no turboshaft engines during WWII.
cimmex

Very true but people who look at the capabilities of modern (or even 1960-70) helicopters and wonder about their usefulness in WW II should be aware that there was a tremendous difference in the capability of a 1960s helicopter and a WW II helicopter.

 

[davparlr]

Very true but people who look at the capabilities of modern (or even 1960-70) helicopters and wonder about their usefulness in WW II should be aware that there was a tremendous difference in the capability of a 1960s helicopter and a WW II helicopter.

WWII helicopters were severely limited in performance and would only be useful for short range reconnaissance/artillery spotting, light materiel support, or light medevac. Insertion and withdrawal of troops, a breakthrough in warfare, was not really possible until several years after the war and certainly weaponization was quite a ways off. However, even the limited medevac capability could have save many lives as was demonstrated in Korea. Also, I suspect carrier ops would also have saved lives.

 

[Shortround6]

The WW II Helicopters that proved useful were usually 2nd or 3rd generation models. SIkorsky going through the V-300 and R-4 Models before the R-5/S-51 shows up. The R-5/S-51 being the first Sikorsky with a rescue winch. They then go through the R-6 and then the S-55. The S-55 uses a different rotor head design with much improved control-ability.

The same holds true for a number of other company's. Piasecki was on their 3rd design (2nd flying) by the time the Military adopted one. And it went though some extensive modifications.

Being able to land and take off from water (an R-4 on floats) doesn't really mean the helicopter can perform rescues on a routine basis. How rough can the water be to set down the early Helicopter (if it has no winch) and you does the rescue? 2nd crewman or pilot shutting things down, climbing from the seat, helping victim on board and then regaining seat and taking off?
Some rescues and evacuations were done. But it was much more feeling out what could be done rather than following a plan or doctrine. The same with ship board use, They were feeling out what could be done. Taking off and landing on a rolling pitching deck presented such problems that it took until the early 60s to solve, see;

Beartrap (hauldown device) - Wikipedia, the free encyclopedia

Yes, Helicopters were being used for anti-sub work well before then but round the clock operation was very difficult let alone operating in bad weather even if visibility was good.

Helicopters in WW II were like Airplanes in the first years of WW I. They were demonstrating their potential but had in no way achieved real capabilities or the ability to really affect the actions of other forces, except indirectly, like by recon. Just like WW I aircraft with the mono-plane, bi-plane,tri-plane, tractor and pusher all competing to come out on top, the single rotor, twin co-axial rotor, tandem side by side rotor, tandem fore and aft rotor and twin inter-meshing rotor set ups were all competing not to mention different rotor head designs.
A more aggressive push may have seen more use of the helicopter in the last year of the war but I doubt it would have been of much use before then.

As far as the AOP role goes. See: Taylorcraft Auster - Wikipedia, the free encyclopedia

The Early Helicopters could perform the role but they weren't needed.

While the ability to land and take-off vertically was useful the increased fuel and maintenance requirements may not have been as desirable.

 

[davebender]

What's wrong with that?

The 1,000 Flettner Fi-282 / Fi-285 helicopters ordered during 1944 would have replaced Fi-256 fixed wing aircraft for artillery spotting. A mission just as important as air superiority and arguably more important then long range bombing. But apparently this crucial mission isn't glamorous enough to earn any respect.

 

[davebender]

Flettner Fl 282 "Kolibri" helicopter - development history, photos, technical data

Apparently the German Navy decided cockpit glass was an unnecessary luxury. Cockpits on Fi-282s produced from 1942 onward were normally open.

 

[Shortround6]

What's wrong with that?

There is nothing wrong with it except the job could have been done by 1000 2/3rds sized (figuratively) Fi-256 for even less money. A wooden framed High wing cabin plane Like a Taylor or Piper or Stinson, using a 100-140hp inline four from either Hirth, Walther or Renault if the Germans hadn't mucked up the occupied countries so badly. While it won't take off and land vertically or use quite as small a field as the Storch but using an engine half the size and without the complication of slats and full span flaps such a plane could get off the ground in 300-500ft (not yds) and have a landing speed in the low 40mph range. Cruising speed of around 100mph. No complicated rotor system to maintain, no complicated drive system.

You are right about not earning respect but using over complicated machines to do the job isn't really a good answer either.

 

[Tankworks]

Irregardless of the technology, I wouldn't want to be over a European WWII battlefield in a low and slow helicopter or for that matter even in a modern Apache, even with complete air superiority there would have been enough flak flying around to make me nervous!

 

[davebender]

No more dangerous then flying the same crucial artillery spotting mission in a low and slow Fi-256.

 

[Juha]

What's wrong with that?

... artillery spotting. A mission just as important as air superiority and arguably more important then long range bombing. But apparently this crucial mission isn't glamorous enough to earn any respect.

INHO armies respected those small planes and their pilots and at least some SS PzDivs hated them in Normandy in 44 and ordered that they were number one targets for the divisional AA units because they were most dangereous Allied planes. Also at Anzio German ground units demanded more LW actions against Allied AOPs and LW tried to comply.

Juha

 

[davebender]

Killing artillery observation balloons was the most important mission for WWI airpower but artillery observation balloons don't get any more respect in WWI discussions then artillery spotting aircraft get in this forum. People would rather talk about those flashy P-51Ds which didn't even enter service until the summer of 1944.

 

[Shortround6]

And of course no one talks about those Fw 190Ds and And Ta 152s either...????

Or the jets and rocket planes

Or the rest of the miracle weapons that were just weeks away from mass production.