WesWorld

The Dutch Luchtmacht is seeking entrants for a competitive fly-off evaluation for two types of rotary-wing helicopters.

The first is a small helicopter suitable for observation duties carrying a crew of at least two and possibly, but not necessarily, also having room for up to two passengers.
The second type is a larger helicopter capable of carrying troops or cargo, at least six soldiers must be carried along with their equipment and personal weapons.
Both types must be suitable for field operations and be of rugged and reliable construction and be capable of operations in tropical and high-altitude environments.

The Luchtmacht will be holding a four-week evaluation at Tikapoo Valley Air Base in Ubangi Shari starting on 1 September 1948. All companies wishing to tender should enter at least two and no more than three airframes of each model offered and should send company test pilots and ground support crews.
At the end of the evaluation the Luchtmacht hopes to place orders for quantities of both types and only the best performing helicopters will be selected.

Quoted from "Hood"

The Dutch Luchtmacht is seeking entrants for a competitive fly-off evaluation for two types of rotary-wing helicopters.

The first is a small helicopter suitable for observation duties carrying a crew of at least two and possibly, but not necessarily, also having room for up to two passengers.
The second type is a larger helicopter capable of carrying troops or cargo, at least six soldiers must be carried along with their equipment and personal weapons.
Both types must be suitable for field operations and be of rugged and reliable construction and be capable of operations in tropical and high-altitude environments.

The Luchtmacht will be holding a four-week evaluation at Tikapoo Valley Air Base in Ubangi Shari starting on 1 September 1948. All companies wishing to tender should enter at least two and no more than three airframes of each model offered and should send company test pilots and ground support crews.
At the end of the evaluation the Luchtmacht hopes to place orders for quantities of both types and only the best performing helicopters will be selected.

The SFG firm of France will send three different types of helicopters to address the two different requirements.
-- Three examples of the SH.20 Cigale in order to meet the observation requirement.
-- Two examples of the new SH.40 Tourbillon (also known in Russia as the Sikorsky S-19) to meet the transport requirement
-- Two examples of the twin-rotor SH.30 Perdrix, also to meet the transport requirement.

The SH.30 is a twin-rotor helicopter that has fourteen passengers, whereas the SH.40 has only a maximum of ten passengers.

Atlantis can offer two examples of the following designs for Observation role...

Quoted

Roth R-3 helicopter

Crew: 1
Capacity: 2 passengers or 460 lb's of cargo
Length: 40 ft.
Height: 10 ft. 10 in.
Empty weight: 3,740 lb.
Gross weight: 4,710 lb.
Powerplant: 1x Roth RV-8 piston 585 hp.
Max speed 110 mph
Rotor diameter: 47 ft.
First flight:1947
Design features: three rotor blades, tricycle landing gear, fully enclosed cockpit/fuselage
(OOC: resembles a Mil MI-1 or PZL SM-2)

Quoted

Ripon/Bloch RB.H100
Crew: 2
Length: 29 ft
Height: 8.65 ft
Empty weight: 1,951 lb. (885 kg)
Gross weight: 2,546 lb. (1,155 kg)
Powerplant: 1x Ripon/Bloch RB-601 piston 180 hp.
Cruise speed 124 mph; 108 kn. (200 km/h)
Rotor diameter: 32 ft.
First flight:1945
Design features: single four-bladed main rotor two-bladed anti-torque tail rotor, fixed tricycle landing gear, fully enclosed cockpit, fully skinned fuselage
(OOC: resembles a Higgins EB-1)

A third design built in Atlantis, the Roth R2 is an Atlantean licence built version of the French Cigale. The design in theory could be offered, however the design has not been entered as France being the initial designer has already submitted the design in these trials.

Quoted

Roth R-2 (Licence built Societe Francaise Du Gyroplane SH.20 Cigale)

Image by Bruce, design by Brock.

Although the Roth-Dorand GII.A had decent performance for a helicopter of its generation, and delivered acceptable service, the type was never fully satisfactory, particularly in its maintenance and accident history. SFG, in collaboration with their Atlantean and Russian counterparts, worked to develop a new type with more utility and safety.

General characteristics:
Crew: 1 (pilot)
Passengers: 1-3 passengers (version dependent)
Length: 13.1 m (43 ft)
Rotor Diameter: 15 m (49 ft 2.5 in)
Height: 3.9 m (12 ft 11 in)
Loaded weight: 2,270 kg (5,004 lb)
Powerplant: Gnome-Rhône 9M (600 hp / 447 kW) radial engine

Performance:
Maximum speed: 94.5 knots (108 mph, 175 km/h)
Max Range: 475 km (295 miles)
Rate of climb: 5.3 m/s (1,043 ft/min)
Service ceiling: 3,500m (SH.20); 3,900 (SH.22)

Armament / Capacity:
- 2 × depth charges or 4 × 25kg bombs
or
- 2 panniers for mail, cargo, or casualty evacuation (1 person / 125kg each)

Variants:
- SH.20: Initial 2-seat prototype, unarmed (1941)
- SH.20M: 2-seat armed variant for Marine Nationale (1942)
- SH.21: 3-seat variant for Army utility and light reconnaissance (1942)
- SH.22: 4-seat variant for Army utility (1943)
- SH.22M: 4-seat variant for Navy utility (1943)
- SH.23-25: Reserved for possible export variants
- SH.26: 3-seat civilian helicopter (1944) based on SH.21
- SH.29: Turboshaft engine testbed (1946)

Britain will send two Fairey Widgeon helicopters.

Length: 41 ft 10 in (12.75 m)
Rotor diameter: 49 ft 2 in (14.99 m)
Height: 13 ft 4 in (4.07 m)
Disc area: 1,898 ft² (176.4 m²)
Empty weight: 4,322 lb (1,969 kg)
Loaded weight: 5,900 lb (2,682 kg)
Powerplant: 1x 520hp Alvis Leonides VII/2 nine-cylinder air-cooled radial engine
Maximum speed: 109 mph (175 km/h) at sea level
Range: 310 miles (500 km)
Service ceiling: 11,800 ft (3,600 m)
Rate of climb: 700 ft/min (3.6 m/s) at sea level
Capacity: pilot and and four passengers, or two litters or light cargo

Also attending will be two Weir W.11 Air Horse heavy-lift transport helicopters.
[Specs as OTL]

***

[cocked up my dates, the Avions-Fairey Gyrodyne won't be ready in time so Belgium won't be sending anything after all]

China offers:

Quoted

Observation role:
HUC-1
General characteristics:
Crew: 1 pilot
Length: 6.30 m
Rotordiameter: 10.1 m
Height: 3.40 m
Disc area: 156.0 m²
Empty weight: 990 kg
max. take off: 1410 kg
Powerplant: 1x Dong Ming with 260 hp

Performance:
max. speed: 150 km/h
cruise speed: 125 km/h
max Range: 350 km
ceiling: 3000 m

Variants:
HUC-1C: Cargo version (250 kg payload)
HUC-1O: Observer version; 1 passenger

Transporter role:

Quoted

HUC - 2:
General characteristics:
Crew: 2 pilots
Length: 9.76 m
Rotor diameter: 10.00 m
Disc area: 74.71 square m
empty weight: 2.932 kg
Max takeoff weight: 4.510 kg
Powerplant: 2x Dong Ming with 575hp

Performance
max. speed: 236 km/h
cruise speed: 182 km/h
max. range: 595 km
ceiling: 6.400 m

Variants:
HUC-2C: Cargo version (up to 700kg or 6 passengers)
HUC-2H: Ambulance version (four stretchers + medical assistance)

The USA will send two designs for the observation role:

Two Bell Model 47A to YR-13/HTL-1 standard.
[Specs as OTL]

Two Bell Model 54 to XR-15 standard.
[Specs as OTL]

Due to the questionable choice of location for the evaluations, Japan will not send anything.

Took a while to sort this out, here are the results of the trials.
Not sure what, if any, orders will result from this at the moment.


Observation
The minimum requirements were: operation from an area 15m x 15m, rotor disc loading no more than 10kg/m2, a power-to-weight ratio of at least 0.20hp/kg, a maximum speed of at least 175km/h, a range of at least 350km, a ceiling of at least 3,000m and the ability to carry at least four persons (including a pilot) or a payload of at least 250kg.

SFG SH.20 Cigale
One of the oldest designs offered, dating from 1943. The ground footprint marginally exceeded the safety minimum area, the disc loading exceeded the limit by 2.84kg/m2, the power-to-weight ratio was the third highest of the group, the speed requirement was just met, the range was the second best of the group and the ceiling also exceed the minimum requirement. The payload capacity fully met the minimum requirement. Bonus points were awarded for the clean design and the ability to carry a litter externally.
The flight performance in the ‘hot and high’ conditions at the test site was reasonably good, being the second best of the observation group but not meeting the minimum requirements.
The total points awarded were 30.

Roth R-3
The design is quite new, only being one year old. The ground footprint marginally exceeded the safety minimum area, the disc loading exceeded the limit by 3.3kg/m2, the power-to-weight ratio was the second highest of the group, the speed requirement was just met, the range and ceiling requirements were met. The payload capacity of 3 men (208kg cargo) was short of the minimum requirement. Bonus points were awarded for the clean design with good view from the cockpit.
The flight performance in the ‘hot and high’ conditions at the test site was reasonably good, with the power-to-weight ratio almost meeting the minimum requirements and allowing a reasonable payload to be carried.
The total points awarded were 25.

Ripon-Bloch RB.H100
The design three years old. The ground footprint was the second best offered due to the compact dimensions, the disc loading exceeded the limit by 5.47kg/m2, the power-to-weight ratio was the worst at 0.15hp/kg, the speed of 200km/h was the best offered, the range and ceiling requirements were met. The payload capacity of 2 men was far short of the minimum requirement. Bonus points were awarded for the clean design.
The flight performance in the ‘hot and high’ conditions was unsurprisingly very poor given the low output of the 180hp engine.
The total points awarded were 15.

Fairey Widgeon
The design is brand new and the largest type in the group which meant the ground footprint exceeded the safety minimum area. The disc loading exceeded the limit by 5.2kg/m2, the power-to-weight ratio was just 0.1hp/kg below the requirement, the speed requirement was just met, the 500km range was the best offered and ceiling requirements were also exceeded. The payload capacity of 4 men (516kg cargo) was the best offered, no doubt due to the larger airframe and engine power on offer. Bonus points were awarded for the clean design with stable undercarriage.
The flight performance in the ‘hot and high’ conditions at the test site was surprisingly poor despite the high power available from the engine. This was largely due to the disc loading with the reduced power available in the conditions.
The total points awarded were 25.

HUC-1
The design three years old. The ground footprint was by far the best offered due to the compact dimensions offered by the co-axial rotors, the design was the only one to offer a disc loading lower than the requirement, the power-to-weight ratio was the poor at 0.18hp/kg, but the small 280hp engine meant that the speed and range requirements could not be met although the ceiling requirement was just achieved. The payload capacity of 2 men (250kg) was judged to just qaulfiy for the minimum requirement in respect to cargo lift. No bonus points were awarded, the technical team worried the co-axial rotor may be harder to maintain in field conditions.
The flight performance in the ‘hot and high’ conditions at the test site was poor and did not meet any of the minimum requirements and altitude and payload were both badly affected due to lack of power.
The total points awarded were 27.

Bell Model 47A (YR-13)
The design is brand new. Given the slight airframe it was not surprising that the ground footprint easily met the safety minimum area. The lightweight airframe was however powered by a small 147hp engine and so the disc loading marginally exceeded the limit by 1.22kg/m2 and the power-to-weight ratio was 0.2hp/kg below the requirement. The the speed requirement was not met, but the range was just met. The ceiling requirements were comfortably exceeded, the ceiling being the second best of the group. The payload capacity of 3 men failed to fully meet the requirement. Bonus points were awarded for the provision for two litters externally. The fabric-skinned tailboom was judged to be easy to repair but potentially not durable enough for field and tropical operations. The skid undercarriage was the only one of its kind offered, it offered better stability but ground handling was hampered so no bonus point was awarded for this feature.
The flight performance in the ‘hot and high’ conditions at the test site was reasonably poor, like the RB.H100, the small engine handicapped the performance.
The total points awarded were 34.

Bell Model 54 (XR-15)
The design is brand new and on paper seemed to be almost perfectly matched to the requirements of the trial in its design and purpose. The ground footprint was well within safety minimum area. The disc loading exceeded the limit by 2.46kg/m2, the power-to-weight ratio was exceptionally good given the 475hp engine at 0.37hp/kg. The speed requirement was almost met, the 320km range however also falling short but the 6,100m ceiling was best. The payload capacity of 4 men was joint best offered. Bonus points were awarded for the modern design and well laid out cockpit.
The flight performance in the ‘hot and high’ conditions at the test site was the best during the trials, the powerful engine lost less power in comparison and had ample reserve and the power-to-weight ratio and the altitude still exceeded the minimum requirements.
The total points awarded were 34.

Results
Rankings:
Bell Model 54 (XR-15)
SFG SH.20 Cigale
Fairey Widgeon
Bell Model 47A (YR-13)
HUC-1
Roth R-3
Ripon-Bloch RB.H100



Transport
The minimum requirements were: operation from an area 25m x 25m, rotor disc loading no more than 15kg/m2, a power-to-weight ratio of at least 0.20hp/kg, a maximum speed of at least 175km/h, a range of at least 500km, a ceiling of at least 4,000m and the ability to carry at least eight persons (including two pilots) or a payload of at least 1,000kg.

SFG SH.40 Tourbillon
The design is brand new and the one single main-rotor design offered which meant the ground footprint easily met the safety minimum area. The disc loading exceeded the limit by 1.62kg/m2, the power-to-weight ratio met the requirement, the speed requirement was not met despite the engine power on offer but the 725km range was by far the best of the group. The ceiling requirements were some 800m lower than the requirement but would have meet the lower altitude specified for the observation type. The payload capacity of 12 men exceed the requirement even though the 650kg cargo did not, but the ability to carry 8 litters internally was highly commended. Bonus points were awarded for the robust design which provided excellent visibility for the two pilots and with easy access to the engine in the nose. The cabin with two large sliding doors was also easy to access.
The flight performance in the ‘hot and high’ conditions at the test site was reasonably good, especially for a single-engine design and with a tropical performance on par with that of the lighter observation type helicopters.
The total points awarded were 28.

SFG SH.30 Perdrix
The design is two years old and is a tandem -rotor type with two engines. It easily met the ground footprint requirement. The disc loading exceeded the limit by 6.99kg/m2, the power-to-weight ratio was met the requirement, the speed requirement was slightly exceeded but the 455km range just failed to meet the requirement. The ceiling was woefully short of the requirements at 2,740m. The payload capacity of 16 men (1,600kg cargo) was the best offered, no doubt due to the larger airframe and engine power on offer. Bonus points were awarded for the easy to access cabin with a large sliding door. The use of two engines was criticised on serviceability grounds given the extra workload required for the ground crews, though it was deemed safer for a tandem-rotor type to have more than one engine.
The flight performance in the ‘hot and high’ conditions at the test site was rated as poor and none of the minimum requirements were met and the ceiling was inadequate.
The total points awarded were 24.

Weir W.11 Air Horse
The design is three years old and quite unique with its rear-loading doors and triple-rotor layout (which was criticised for its large area footprint and complexity). It was the only transport design offered that exceeded the safety minimum operating area. The disc loading just exceeded the limit by 1.41kg/m2, the power-to-weight ratio met the requirement, the speed requirement was surprisingly comfortably exceeded, the range requirement was also slightly exceeded and the ceiling requirements were also exceeded by far the best performance. The payload capacity of 3,050kg was unmatched and the cabin was spacious enough for multiple needs and even for small vehicles which earned it bonus points.
The flight performance in the ‘hot and high’ conditions at the test site was surprisingly good for such a large airframe and the single (albeit powerful) engine. The ceiling attained was still far above the minimum requirements with a reasonable payload.
The total points awarded were 33.

HUC-2
The design is one year old but in concept is outdated with its twin rotors on outriggers. The ground footprint was easily met due to its small overall dimensions. The disc loading was actually 1.41kg/m2 below the requirement which was very commendable. The power-to-weight ratio was also the best offered as was the speed. The range was the worst on offer at 420km but the ceiling easily exceeded the requirement at 6,400m. The payload capacity of 8 men (700kg cargo) was judged to be poor considering the high performance obtained, but the cabin was large enough for four litters.
The flight performance in the ‘hot and high’ conditions at the test site was the best of any of the transport category types and the ceiling attained was good and the power-to-weight ratio on offer was still adequate.
The total points awarded were 35.

Results
Rankings:
SFG SH.40 Tourbillon
Weir W.11 Air Horse
HUC-2
SFG SH.30 Perdrix