William McKinney '63 - bill@4cmg.com

F80 -- Korean War Jet Fighter

Designed at the end of World War II, first flown in 1947, the F80 Shooting Star became one of our first dog fighting jets. Introduced in Korea, the F80 became the first aircraft to score a kill in all jet air combat.

Superseded by the swept wing F86 Saberjet in the skies over Korea, the F80 lived on to become the T33, the jet trainer for generations of pilots stepping up to jets from prop planes.

To make the early trainers they just took the machine guns off the F80 and replaced the space with a second seat and control panel for a student. Eventually the production line made just the trainer which sold all over the world.

The markings on this aircraft are of the Thunderbirds which are the Air Force's exhibition flying team, like the Navy's Blue Angels.

Flying the T33

After a good session of ground school, we did the safety walk around then climbed up the stairs leaning against the fuselage to the cockpit, closed the canopy and fired up the engine.

Taxiing is another matter. The nose wheel is free wheeling, not connected to the rudder pedals or other steering mechanism.  You taxi down the centerline with short taps on the right and left brake (which are on top of the rudder foot controls) to bring you back on the centerline.

With a maximum gross takeoff weight of 16,800 pounds, compared to a Cessna 170 with 2200 pounds, or a Pitts Special at 1600, this is a piece of heavy iron. The takeoff roll is long, almost 4,000 feet. The angle of ascent is low to build up airspeed and feed air into the engine. Too high an angle of attack can starve the engine for air because of the angle between the oncoming air and the air intake ducts.

At 150 knots I was given control of the stick and power and started a right ascending turn to the practice area over Lake Cochiti, 20 miles southwest of the Santa Fe airport. The feel on the stick was one of easy quick responsiveness. As you think a turn and start to move your hand, the aircraft is right there with you responding smoothly to every light adjustment.

The visibility when I fly in New England rarely exceeds 12-20 miles. But the visibility aloft here was 50-60 miles revealing vast dark green mountain ranges amid splotches of brown, tan, white and yellow desert stretched across the horizon.

Aerial Maneuvers

In my lesson I flew Chandelles, which are climbing turns at a high angle of bank, raising the nose to gain altitude and complete a 180 degree turn. Then we did some straight and level flight.  Then 360 rolls, where the aircraft rolls on its axis to inverted flight and continues over the top to upright flight.

The instructor then demonstrated an Immelman. It’s a way to make a 180 turn, but you go up vertically instead of right or left at the same altitude.  We started the maneuver at 14,000 feet, dove to gain air speed to 12,000 approaching 400 knots, then a 3 G pull up to go vertical and we shot up to 18,000 in a flash. At the top of the loop we were inverted having made the 180, then rolled out upright.

We did accelerated stalls right and left where the aircraft ceases to fly and literally falls in the air out of control. This in order to practice recovery techniques: centering the stick and pushing it forward. The reassuring thing about doing accelerated stalls in the T33 is that it gives you a real warning when it’s happening.

As the aircraft is made to stall in a high speed, high bank, tight, turn, it undergoes a distinct shuddering that warns you what is happening. In some aircraft an accelerated stall is not so noticeable and the bottom can fall out quickly.

 On the way back to the airport I worked on smooth descending turns and then the airport traffic pattern.

Differences between flying a prop plane and a jet

The day before I had the fun of flying another airplane made in 1947, the Cessna 170.  This plane has a high wing which is great for visibility. It has a tail wheel, instead of a nose wheel, which means it handles very differently on the ground and in windy conditions. And it makes an interesting contrast to the T33.

Power Management
A high performance prop plane has a Power Quadrant consisting of the throttle to control the manifold pressure (usually to a max of 25 inches), a lever to manage the fuel and air mixture, and a knob to manage the pitch of the propeller. The pitch of the propeller controls engine RPM (at any given manifold pressure) and is usually held at 2500 for take off and climb, 2400 for cruise power.
 
The jet has one control for fuel and power, a lever you push forward to add power (fuel and air). The readout is a tachometer that shows the percentage of power the engine is developing in relation to full power. You take off at 94% power, taxi at 20-30%.

The big difference with power application is that with prop planes pushing the throttle forward results in instantaneous power and thrust.

The T33’s jet engine develops full power at 12,500 cycles (RPM) instead of 2500 with the reciprocating engine. When you start to add power it can take many seconds for the engine to spool up to the new power setting. In close proximity to the ground those seconds without power or thrust can be critical.

Rudder
When asked about rudder use, the T33 instructor said “My idea of a rudder is that it belongs on a boat.” He means that there is very little need for the rudder, only a slight touch in turns. The ailerons do most of the work in pointing the ship.

In contrast the Cessna 170’s instrument panel has a Slip and Skid indicator. That has a ball in a curved horizontal liquid tube. When the ball moves to the right or left you are out of alignment, slipping or skidding through the air. You use the rudder (foot pedals) to align the tail in the direction of the turn and that will keep the ball centered. Needless to say the T33 has no Slip and Skid indicator.

Performance
Top speed for the Cessna 170 is 122 knots. It stalls at 50 knots, so you land at 60 or 65 knots. 

The T33 has a top speed of 500 knots which is close to 600 MPH. The landing speed is 110 knots. It can fly inverted for only 20 seconds as it doesn’t have dual engine oil and fuel pumps.

Climbing and Descending
The Roll Royce engine takes a while to gain airspeed but at 400+ knots you can climb 3,000 feet a minute. The 170 climbs at about 700 feet per minute. When it reaches cruise altitude it trims out to 104 knots cruise speed.

In the 170 when you want to descend you reduce power to lose altitude, maintaining a level attitude. With the T33 when you want to descend, you point the nose down and fly down.
 
Landing
As with the take off in the T33, final approach is a much lower, shallower angle. With Flaps, air brakes and gear hanging out you literally fly it onto the ground. You keep power at 40% so you can cycle up and take off again if you have to go around. (Prop engine would be at idle)  Touch down at 110 knots with a slight flair (nose up) at the last minute to land on the main wheels.

You court disaster if you stand on the brakes (no anti-lock brakes in those days) with 12,000 pounds behind you it's very easy to lock a brake and blow a tire.

The Cessna 170 landed at 60 knots. You fly the pattern at 80-90 knots its best glide speed. There is a high angle of descent, so if the aircraft lost the engine it could literally glide to the runway.

On the ground in the 170, since it's a tail dragger, (with a tail wheel not nose wheel) you dance on the rudder pedals to keep nose pointed in the right direction and the tail on the centerline.

Fuel consumption
Cessna 170 – 7.5 gallons an hour of regular avgas
T33 – 400 gallons an hour of JP fuel. As the instructor said, “It’s not a Honda.”

So, as you can see, each airplane has its advantages.

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