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Cessna Model 172 Skyhawk

Cessna designed the Model 170 and its successor the Model 172 as "family" aircraft. Both planes were enormous commercial successes, and have been built in larger numbers than any other aircraft to date.

The Model 170 was designed in 1947. In this model, the landing gear was in the convention "tail dragger" design, with an all-metal fuselage and a cloth-covered aluminum wing. In the mid-1950s, the Model 172 was introduced, which was essentially the same plane as the Model 170, but with a squared-off tail rudder and tricycle "Land-O-Matic" landing gear with a steerable front wheel for taxiing. Although this fixed-gear design adversely affected aerial performance, it was a huge commercial success.

The plane has room for four; one pilot, one instructor, and two passengers. Although typically a civilian aircraft, Cessna delivered a number of Model 172s to U.S. forces between 1966 and 1970. These planes were used for pilot screening and elementary flight training. The plane was also license built by Reims Aviation in France beginning in 1963.

The Model 172 burns 6 gallons of aviation fuel per hour at routine usage. A full load of fuel costs $10.60 (or $315 in 2006 dollars).

 

Cessna Model 172R Skyhawk (TL7)

Subassemblies: Light Fighter chassis +3; Recon wings with STOL option +2; 3 fixed wheels +0.

Powertrain: 119-kW aerial HP gasoline engine with 119-kW prop and 53-gallon standard fuel tank [Wings].

Occ.: 2 CCS and 2 CPS Body.

Cargo: 0

 

Armor F RL B T U

All: 2/3 2/3 2/3 2/3 2/3

 

Equipment:

Body: Backup driver option, medium radio transmitter and receiver, navigation instruments.

 

Statistics:

Size: 35' 7"x26' 11"x8' 9" Payload: 0.57 tons Lwt.: 1.15 tons

Volume: 144 Maint.: 131 hours Cost: $2,297

HT: 7. HPs: 25 Body, 35 each Wing, 5 each Wheel.

aSpeed: 139 aAccel: 2.5 aDecel: 9 aMR: 2 aSR: 1

Stall Speed: 49 mph.

gSpeed: 147 gAccel: 7 gDecel: 10 gMR: 1 gSR: 3

Ground Pressure: Low. 1/3 Off-Road Speed.

 

Design Notes:

Although the Model 172R crosses the line into TL7, the above craft was designed at TL6. It could still represent almost any of the early or current Cessna Models. The current cost for a Cessna 172 is around $100,000.

The design exceeds actual take off weight by 500 lbs. despite reducing the weight (and cost and HPs) of the chassis by 50%. Crew/passenger weight may be a bit excessive--the pilot I flew with was running calculations to check takeoff weight despite the four people weighing 170 lbs. or less.

The design purchases 60 gallons of gas tanks. The actual value is listed. Calculated aSpeed and Stall Speed are 129 and 38 mph respectively; the actual values have been substituted.

Actual wing area is 174 sf and was used for all performance calculations. Using the calculated gSpeed at 1/3 Off-Road speed (49 mph), the plane can still meet its stall speed of 49 mph (or exceed 38 mph, if your use the calculated values for both instances), and could potentially get airborne in a bumpy field, at the GM's discretion.

 

Variants:

Cessna liked to introduce new models annually (like automobile manufactures) for marketing reasons.

The Model 172 was first designed in 1955. It was powered by a 108-kW engine. 3,757 built.

The Model 172A replaced the 172 in 1960. It has a swept vertical tail surface that improved looks but not performance. 994 built.

The Model 172B (1961) had shortened landing gear, a baggage door, and a redesigned cowling. 989 built.

The Model 172C (1962) increased maximum takeoff weight. 810 built.

The Model 172D (1963) redesigned the fuselage to allow for the "Omnivision" rear cabin window. 1,011 built.

The Model 172E had electrically actuated flaps. 1,209 built.

The Model 172F had a more modern engine. 1,400 built.

The Model 172G was a 172F with only minor changes. 1,474 built.

The Model 172H had a redesigned nose gear and new engine cowling. 1,586 built.

The Model 172I introduced the new Lycoming engine. 649 built.

The Model 172K (1971) had enlarged side windows. 2,055 built.

The Model 172L (1972) has a larger fin fillet, and other minor changes. 1,535 built.

The Model 172M (1973) introduced a drooped leading wing edge to improve stall characteristics. 6,825 built.

The Model 172N (1977) installed a more powerful (but problematic) 119-kW engine.

The Model R172K Hawk XP was a 172N with a 145-kW Continental engine.

The Model 172RG Cutlass (1981) featured a new 134-kW engine, a three-bladed propeller, and retractable landing gear. 1,191 built.

The Model 172Q Cutlass (1982) was the 172RG with fixed landing gear. 391 built.

Production of the Model 172 ceased from 1986 to 1996 due to product liability laws, which held manufactures responsible for virtually any accidents involving their aircraft.

The Model 172R Skyhawk (1997) is the only current production model. It features a 119-kW engine, fixed-pitch propeller, and new avionics.

 

From the Aerodrome for GURPS

2008 by Jim Antonicic