The PV-2 Lockheed Harpoon Air Tanker

The PV-2 is Lockheed's Model 15. "P" stood for Patrol and "V" stands for coming out of the Vega factory in California. The 2 is the forerunner of the PV-1, which had same engines, but smaller wings and horizontal stabilizer along with shorter fuselage. The rudders are fabric. It was the last twin-tail aircraft built by Lockheed. The ailerons and all the trim tabs, along with the fuselage, I understand from my friend Dave Wardall, (retired CDF/CAL FIRE Deputy Chief Aircraft Maintenance and Engineering/FAA Aircraft Structure engineer) were 2024-T-3 (copper based alloy). The PV-2 is a twin-engine monoplane aircraft, submarine patrol bomber. Lockheed had designed the airframe to be quickly disassemblyed for overseas shipment, if necessary, by having three fuseladge sections that bolted together: the fuseladge is mated to the center section, the nose and tail section bolts on. The only fabric control surface on the aircraft is the rudders. The PV-2 has high wing loading and Fowler flaps for low speed stability.
 
Wing span: 75' 
Length: 51' 91/2 " 
Height 11' 11" 

ENGINES
The PV-2 has two, 2000 hp each, Pratt & Whitney, Double Wasp 18 cylinder, air cooled R 2800-31 engines with 16-9 gear reduction and Hamilton-Standard three-bladed automatic hydro-full feathering props. The R-2800-31 had the B series cylinders and supercharger with single stage two speed blower. The Harpoon called for 100-130 av gas, but when it wasn't produced anymore, took on 100LL. The engines took 60WT oil. 

ENGINE HEADS and COOLING
The one PV-2 aircraft we had formerly belonged in the '60s to Brent Conner's Dad's, Capt. Denny Conner, Tanker 30 . N7459C, T-30 had the "C" series cylinder, which was better than the B series, for cooling. The engine nose cases were different gearing, as well. I have a b&w photo of T-30 from the 60's, but unfortunately it's back in WY storage. Brent Conner probably has the original.

SUPERCHARGERS 
Under FAR Part 137, under Restricted Category operation, the gross weight was 33,000 lbs. Empty Weight average around 19,500. 
We, like other operators, kept the superchargers wired in low blower. This was due to engine oil sludge. There was problems with the sludge and the blower clutches and to my knowledge no PV-2 air tanker operator ever used the high blower. 

TAIL WHEEL DOORS
The civilian operated PV-2 never operated at high altitude. The tail wheel was locked in a "down position" due to problem with retardant drops, the gear door mechanism would get mud goop-ed up there and caused corrosion problems, so most operators kept the tail wheel in a fixed lock-down position. 

OIL
The PV-2 uses MiL H-5606 hydraulic oil. The main hydraulic system has around a five+ gallon capacity hydraulic reservoir behind the captain's seat with a hand pump by the captain's seat. The main hydraulic system operates brakes, flaps, and retardant doors. There is an emergency reservoir (capacity around a gallon) along with a hand pump, With the emergency system, you can lower the main gear and use the brakes (toe brakes or hand pump), but have to manually lower the tail wheel.

FUEL and OIL CAPACITY
Under civillian operation, the PV-2 had the capacity of 988 gallons of fuel. The fuel tanks were the original military self-sealing bladders and hard to find original replacements and expensive to have made. The engine oil tanks held around 20 gallons and the wing tanks around 25 to 30 gallos. Some PV-2 aircraft varied on wing oil tank capacity. 

FUEL MANAGEMENT
The wing fuel tanks held 245 gallons per wing, but we carried no more than 200 gallons for wing loading purposes. The thing was to first use the Rear Center Section (RCS) tank fuel. The fuel system you had to pay attention to. You transfer fuel from whichever tank to the Front Center Section (FCS) tank, which, along with the RCS, is on the inboard side of the engine or part of the center section of the fuselage .The FCS tank on each wing has an electric boost pump. The FCS fuel is pumped to the engine driven fuel pump and fed fuel to the engine. The FCS fuel tank holds 116 gallons per side and RCS fuel tank holds 133 gallons per side. Using the electric transfer pump either automaticly or manual (I recall we had use of only the manual toggle switch that is spring loaded) and the transfer valve turned to selected tank, fuel could be bypassed from any tank to the engine or crossfed from any tank on one side, to the engine on the other side. 

The earlier operators or the government removed the forward and aft bomb bay fuel tanks and the cabin fuel tanks. Everything non-essential and considered dead weight was removed. All military version had wing drop fuel tanks. 

RETARDANT and AIRCRAFT RESPONSES
The PV-2 air tanker was an Interagency Airtanker [Air Tanker] Board (IAB) Type 3 air tanker, 9800-1200 gallons) or meduim size tanker, for its day. The retardant tank for the PV-2 were installed in the bomb bay area. T-38's retardant tank had two doors for two sections i.e. a capacity of 525 gallons per side = a total of 1,050 gallons. T-39's is a two door tank of 600 gallons per side = a total of 1200 gallons. 

Bill Hyler describes the emergency retardant system: "It was air actuated in case of loss of all hydraulic pressure. The air bottle and valve were located behind the co-pilot's seat. The cylinder located over the [retardant] tank midway aft of the cockpit." The PV-2 has no nasty flying characteristics. Dropping a salvo-load of retardant, the bomber will step-climb up, but there's no violent or extreme pitch change. RALCO found out that firebombing with flaps down warped the flap rails. The PV-2 faired well without flap useage on a fire drop. The PV-2 in a imminent stall and/or power off, there's some tail buffeting, slight roll and moderate altitude loss. Flying at altitude in moderate chop, the PV-2 will "wallow" around. With an engine out, the nose becomes heavy. With one engine, you can't hold altitude with the landing gear and more than 20% flaps down. With an engine out, you can't crank in full rudder trim, as this will cause tail buffeting and vibration and knock the dope off the ruddesr. Therfore you have to hold rudder pressure on the good engine to hold straight flight. 

The retardant tanks for T-38 and T39 were aluminum and built by Ralph Johnson, who owned RALCO and Master Equipment Company. Ralph operated a C-54 and the PV-2s for aerial firefighting. He also operated PV-2, and before the PV-2s, I believe Douglas B-18 Bolo bomber for spray contracts. Weinaorco, out of Wenatchee, Washington, operated PV-2 tankers back in the 60's, built their tanks out of fiberglass. 

GROUND OPERATIONS

Taxi: use differential power and brakes for taxing turns (and crosswinds). Tapping a brake left or right to taxi straight. View over the nose not difficult for a tall person. On the captain's side, only: the PV-2 has hydraulic toe brakes on the top of the rudder pedals, which when fully depressed and held, sets the parking break. The copilot has only rudder pedals and no break ops. 

Take-off: Due to the props right torque, you start your takeoff run by lining up on the runway and locking your tailwheel, setting your boost pump in the fast position, then advancing the left throttle a little ahead of the right throttle with a bit of right rudder to keep her straight down the runway. Around 40 knots, the tail would pick up and she'd track well down the runway. Depending on the load, density altitude and temp, the PV-2 would rotate around 90kts.
 
Landing: The PV-2 has a low stall speed. With gear and full flaps down, she'd quit flying around 82 knots. Transport landings were standard operation. 
The electrical system is 24v, DC, negative wire, single ground wire. There is two engine driven generators and and APUs were installed in tail, along with a battery. 

Other PV-2 air tanker operators were Weinairco, Central Air Service (Bill Dempsey), Bruce Kinney (Kinney Air Tankers), Globe Air, RALCO/Master Euipment Company, Denny Conner.

Hirth Air Tankers was last PV-2 aerial firefighting operator (1987-2003), operating T-38, N6856C and T-39, N7080C. In 1997, T-38 was lost flying on a fire in Pennsylvania. 

The last air tanker contracts were flown in 1998 in Pennsyvania and Wyoming. I did bid competitive contracts in Pennsylvania up to 2003, but couldn't compete with the Single Engine Air Tanker (SEAT), which underbid the PV-2. 


Airspeeds (KIAS) 
Vfe 120 
Vle 150 
Vne 309 
Va 135-150 
Vse 105 
Power Settings 
METO 52" 2700 rpm 
Climb 47" 2400 rpm 
Cruise 32" 2100 rpm


