Pitcairn PA-23 portable autogyro

Pitcairn PA-23 ultralight autogyro

The OSS requested Pitcairn design a very light and portable observation autogyro that could be air dropped, carried on pack animals, or otherwise deployed with small groups of agents behind enemy lines. The result was a fairly low-performance autogyro that, due to efforts cutting weight, tended to be a bit fragile and unreliable.

The PA-23 was an open frame body using a pusher engine configuration with tricycle landing gear. The pilot sat completely exposed at the front, with the MG (or auxiliary tank) below him and a small cargo box behind his seat. Due to the low altitude the autogyro was normally operated at low altitude (usually between 100 and 1,000 feet), the pilot rarely wore a parachute. He would, however, sometimes carry a bag with grenades; most were colored smoke grenades for marking locations, but one or two fragmentation grenades were often carried. The pilot also normally carried a pistol 'just in case'.

About fifty were built, mainly deployed in the CBI (China-Burma-India) Theatre, although a handful were sent to the British, where they saw limited use in France and Greece. Overall, the PA-23 was a disappointing design that had to compromise too much for the desired performance, but there was no other craft to fill it's role (albeit a role that one might question needed filling).

A number were taken over by the Merchant Marine and used as submarine spotters on freighters (such as Liberty ships) and tankers. While the PA-23 had to means of destroying a submarine it located, it could guide escorting warships to the spot. The only modification needed for those ships carrying a PA-23 was a plywood ramp about ten yards long and three yards wide and a small shed adjacent to it to to stow the autogyro when not in use.

Crew consists of the pilot. The PA-23 uses 2.7 gallons of aviation fuel per hour.

Subassemblies: Rotary Kite Chassis +0, folding Rotors +0, three fixed Wheels -2
P&P: 59.7 kW HP gasoline engines w/59.7-kW prop, 13 gallon standard tank [Body]
Occ: 1 MCS Cargo: 0.5

Armor
Body: 2/4
Rotors: 1/1C
Wheels: 2/3

Weaponry
Aircraft LMG/Browning M-2[Body:F] (500)

Equipment
Body: Medium range radio receiver and transmitter.

Statistics

Size: 20'x20'x7' Payload: 348 lbs Lwt: 707 lbs

Volume: 8
Maint.: 231 hours Price: $750

HT: 7
HP: 6 [body], 16 [rotor], 1 [each wheel]

aSpeed: 41
aAccel: 10
aDecel: 16
aMR: 4
aSR: 1
Stall: 16 mph

Take-off roll: 7 yards. Landing roll: 1 yard

Design Notes
The open frame armor body only protectcs the autogyros coponents on a roll of 1-2 on 1d6. The pilot is not protected by the armor at all but the caro box (and it's contents) gets the full DR 4 at all times.

The MG and ammo were designed to be removed and replaced with a 6-gallon auxilliary (not drop) fuel tank.Most OSS teams that used the PA-23 rarely used either and used freed-up weight to carro cargo strapped to the airframe.

At 25 mph, the PA-23 has a range of 120 miles. However, as this is a bit too close to stall speed for some pilots, they prefer to cruise at a higher speed; at 32 mph, range is 80 miles.

To better match historical autogyros, rotor area was raised to the 1.75 power in stall calculations and 1.5 power in speed calculations. Takeoff was divided by 3 and landing distances by 10.

The calculated stall speed was 8 mph. While the changed formulas above work for most auotgyros, it can produce strange results for very small or very large ones (especially for a chassis like the rotary kite, which has an oversized rotor). Thus, stall was doubled to raise it to a more realistic number. This was used to calculate takeoff and landing distances.

Size: 20'x20'x7'	Payload: 348 lbs	Lwt: 707 lbs
Volume: 8	Maint.: 231 hours	Price: $750