Cessna 210 Short Field Performance

August 16th, 2011

Ths following post is an exert from the Cessna 210 Training Manual (http://www.lulu.com/product/paperback/cessna-210-training-manual/5342141), by Oleg Roud and Danielle Bruckert

Short Field Takeoff

For the minimum takeoff distance to clear a 50ft obstacle, the recommended procedure for a short field take-off in the AFM specifies:
Wing flaps 10 degrees;
Apply maximum power against brakes, full throttle, 2850RPM;
Elevator should be slightly low, lift off early;
Maintain 75kts / 85mph until obstacles are cleared;
Retract flaps once obstacles are cleared, and after safe retraction speed of 80kts/90mph is reached.

Note there is no speed specified for lift off in the short field procedure. With a tail low attitude the aircraft will become airborne as it gains flying speed. This technique is recommended as the sooner the aircraft is airborne frictional drag is removed, however the aircraft needs to be accelerated over the high contributing induced drag at low speed before it will climb away. Another drag curve related affect of the C210 is that precise control is required for this acceleration phase, and very little or no climb performance will be obtained until this is achieved.

If the aircraft is loaded with an aft centre of gravity limit, or when taking off from an uneven runway, it may become airborne well before the recommended lift off speed. This is very dangerous situation as the aircraft will fail to overcome the induced drag, maintain a very slow speed (often well below gear retraction speed) and fail to climb. To overcome this, the aircraft needs to be accelerated in ‘ground effect’ until sufficient speed is regained to enable gear retraction and safe climb out. If insufficient clearway is available for acceleration this method will lead to an inadvertent impact with terrain, therefore it is very important to guard against early lift off.

Because of the complexity of the handling after takeoff at too low speed, werever sufficient runway is available, it is advisable to rather keep the aircraft on the ground longer for a clean lift off, which will significantly improve the climb handling, similar to the improved climb technique used in multi-engine aircraft.

The figures and procedure above, are those prescribed in the flight manual for the maximum performance takeoff at maximum weight. Any deviation from the recommended procedure should be expected to give a decrease in performance.

Soft Field Takeoff

Soft or rough field takeoffs are performed with 10 degrees wing flaps by lifting the aeroplane off the ground as soon as practical in a slightly tail-low attitude. If no obstacles are ahead, the aeroplane should be leveled off immediately to accelerate to Vy (best rate of climb) for best initial climb performance. If there are obstacles, the aircraft should be accelerated to Vx (best angle of climb) and this speed should be maintained until all obstacles are cleared.

Short Field Landing

For a short field operation the exact speed is specified in the flight manual for the weight and conditions applicable. Positive control of the approach speed and descent should be made to ensure accuracy of the touchdown point.

The landing should be positive, with a high nose attitude (on the main wheels) and as close as possible to the stall.

In early models there is only one speed specified for landing, at maximum weight. At lower weights the aircraft will tend to float in the flare, and it is advisable to be prepared for this. Err towards the lower side of the speed, and begin reducing the power and speed early during the flare for landing. However when at the correct weight, the correct speed must be maintained, see further below regarding low speed handling.

Low Speed Handling

The Cessna 210 contains a relatively sharp drag curve, often blamed on the laminar flow wing. This characteristic means it is much less forgiving than most Cessna single engine types in low speed operations.

When flown slightly below the reference speed the aircraft seems to ‘“drop out of the sky’ and can require drastic recovery methods, for example application of full power to regain profile. Conversely if flown slightly too fast, the aircraft is difficult to slow down, tends to ‘float’ during the flare, and runway overruns can await the improperly prepared pilot. Forcing the aircraft onto the ground in response to this situation is the worst thing a pilot can do. This often leads to bounces which lead to porpoising and has resulted in many an inadequately trained pilot being left with a collapsed nose wheel or worse.

To avoid landing problems from poor approach profiles, more care should be taken in maintaining speed and slope during the approach. Crossing the ‘barrier’ at the right height and speed is half the battle in carrying out a landing you can proudly ‘walk away from’. The second part requires a smooth transition into the landing attitude allowing the speed to bleed off whilst raising the nose until the main wheels touch down at the minimum speed (for the conditions) in a nose high attitude.
Gear Retraction at Low Speed

The sharp drag curve also requires special care on takeoff, particularly where maximum performance is concerned. Retraction of flap or gear at minimum speeds will cause significant increases in drag when the aircraft is suddenly moved to the steep “back-side” of the drag curve. This can mean a marginally performing aircraft is now not performing, and assuming you are already at full power, height must be sacrificed to regain the necessary speed for climbing. Similarly lifting off at a too low speed results in little or no climb performance.

Cessna Training Manuals

2 Comments »

  1. Joe says

    Good article. I prefer to stay on the runway as long as possible, get as much airspeed as possible before lifting off….. to getting airborne too early and waffling along at low airspeed in a high drag configuration. For an uneven and bumpy runway or one with tall grass I have used flaps 20 for a short field take off to get off the runway quickly however once off the ground you have to keep level to accelerate to climb speed. Love a 210 !!

    December 23rd, 2011 | #

  2. rsv says

    An interesting point you’ve mentioned Joe, late model C210s permitted Flap 20 takeoff for soft fields, whilst early ones didn’t. Why? The same way early model C172s recommended flap up for a short field takeoff but no one ever seemed to agree with this. I have to admit we even had a name for this type of procedure: “bush flap”, for the C210 this setting was not flap 20 but setting the flap to the aileron resulting in around 15 degrees.
    It’s an extremely difficult one when you know the aircraft performs better (if there are no climb out issues), but the manufacturer hasn’t given you the option of the figures for it.
    What would I do if I arrived for a pick up at a soft sandy strip that the owner has sworn was in excellent condition? Gee – sure glad I don’t need to make those decisions these days…

    December 26th, 2011 | #

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