What is the Cessna Skymaster and why is it push-pull?
The Cessna Skymaster is a high-wing, twin-engine utility aircraft with one engine in the nose pulling and another behind the cabin pushing. Cessna chose this centreline-thrust layout to retain twin-engine redundancy while greatly reducing the strong asymmetric yaw and control difficulty that a conventional wing-mounted twin can produce after an engine failure.
How does the Skymaster's push-pull layout work?
The front engine drives a conventional tractor propeller, while the rear engine drives a separate pusher propeller aligned with the same longitudinal axis. The engines do not share a shaft and are not a contra-rotating pair; each is managed as an independent engine with its own throttle, propeller and mixture controls.
The rear propeller sits behind the fuselage, with twin tail booms supporting the horizontal and vertical tail surfaces clear of its disc. This distinctive arrangement gives the Skymaster its recognisable shape and allows both thrust lines to remain close to the aircraft's centreline.
Most people use “Skymaster” to mean the Cessna 337 family, although the earlier fixed-undercarriage 336 introduced the basic concept. Our guide to Cessna model roles and configurations shows how this unusual twin fits alongside the company's more conventional singles and business aircraft.
Why did Cessna choose centreline thrust?
Centreline thrust makes an engine failure easier to control because the surviving engine does not pull strongly from one wing. In a conventional twin, losing an engine leaves the other engine producing off-centre thrust, causing pronounced yaw towards the failed side and demanding prompt rudder input.
| Characteristic | Conventional wing-mounted twin | Cessna Skymaster |
|---|---|---|
| Engine position | One engine on each wing | One ahead of the cabin and one behind it |
| Engine-out yaw | Strong asymmetric thrust | Much smaller because thrust stays near the centreline |
| Pilot workload | Rapid identification and substantial rudder input may be required | Directional control is generally easier, but the failed engine must still be identified and secured |
| Main packaging drawback | Engines are relatively accessible and receive direct airflow | The rear installation complicates cooling, access and noise control |
This does not mean that front- and rear-engine failures are aerodynamically identical. Propeller drag, cooling airflow and the effect on aircraft systems can differ. The Skymaster simply avoids the severe left-versus-right thrust imbalance associated with widely separated engines.
Can a Cessna 337 fly safely on one engine?
A Cessna 337 can fly on one engine when weight, altitude, temperature and aircraft condition permit, but a positive climb is not guaranteed in every situation. Like any light twin, its one-engine-inoperative performance can become marginal when heavily loaded or operating from a hot, high airfield.
The centreline arrangement improves controllability; it does not restore the lost power. A windmilling propeller still creates substantial drag, so the failed engine must be identified and feathered according to the applicable checklist. Gear and flap position also have a major effect on climb performance.
- Confirm both engines before take-off: reduced yaw can make a rear-engine power loss less obvious than an engine failure in a conventional twin. Cross-check the engine instruments and expected acceleration.
- Watch rear-engine temperatures: the aft installation receives less straightforward cooling airflow, especially during prolonged low-speed ground operation. Use the model-specific cooling procedure and cowl flaps where fitted.
- Use the performance charts: published single-engine climb and ceiling figures matter more than the fact that the aircraft remains easy to point straight.
- Keep clear of both propellers: the rear propeller is less conspicuous to passengers and ground personnel than a normal nose or wing-mounted propeller.
A related training issue is that the Skymaster does not reproduce the same asymmetric-thrust handling as a wing-mounted twin. Some licensing authorities may therefore place a centreline-thrust limitation on a multi-engine qualification completed solely in this type; the exact rule depends on the licensing jurisdiction.
What are the main Cessna Skymaster versions?
The Skymaster family includes fixed-undercarriage, retractable, turbocharged, pressurised and military variants, so specifications cannot safely be applied across every model.
| Version | What distinguishes it |
|---|---|
| Cessna 336 Skymaster | The early production design, using fixed landing gear |
| Cessna 337 Super Skymaster | The developed retractable-undercarriage family most commonly associated with the name |
| T337 and P337 variants | Turbocharged and pressurised developments intended for higher-altitude operation |
| Cessna O-2 | A military derivative used for observation and forward air-control duties, with equipment varying by version |
Cabin arrangement, engine output, weights and operating speeds vary substantially between these versions. Pilots and simmers should use documentation for the exact model rather than treating every 336, 337 and O-2 as interchangeable.
What should flight-simulation pilots watch for?
A convincing Skymaster simulation needs independently controllable engines and credible engine-out drag, not merely the correct external shape. A common mistake is using one combined throttle axis and then assuming an individual engine failure has been reproduced properly.
Assign separate engine controls or engine-selection commands where the simulator and hardware permit. During a test at safe altitude, verify that each throttle affects the correct engine, that a stopped or windmilling propeller behaves differently from a feathered one, and that the remaining engine does not provide unrealistic climb performance.
For FSX, our freeware civil Skymaster aircraft demonstrates the basic push-pull configuration. The expanded 337 and O-2 simulation package also covers the military derivative and makes the relationship between the two versions easier to examine.