Why Bother With Retractable Gear?

The pecking order even extended into the elite class of retractable-gear models. Beech Bonanzas and Cessna 210s, for instance, kept their gear snuggly buttoned up behind fully enclosing clamshell doors, while Mooney Mark 20 and Piper Comanche pilots displayed a bit of naked tire exposure in their open-wheel wells. Simplicity eventually won out at Cessna, and a redesigned Centurion with open maingear wells appeared in 1979. Bonanzas, to this day, remain sleekly streamlined in cruise.

But there has now turned out to be other ways to hop up cruising speed, other than folding away the landing gear. In 1999, Cirrus Design brought out its revolutionary SR20, the earlier version of which could zip along wheels-down at 145 knots or better on 200 hp. The Diamond DA40 followed soon thereafter, delivering 140 knots or more on just 180 horses.

Part of the solution for both planes was adding a constant-speed propeller that could optimize the prop's pitch for both climb and cruise. But most of the speediness achieved by this new generation of general aviation airplanes stemmed from slick fiberglass construction, devoid of lap seams and rivet heads. Careful fairing of the gear legs protruding in the breeze minimized their drag, and an overall sleek aerodynamic shape, made possible through the use of composites, cut parasite drag, too.

Thus, the urgency many pilots once felt for moving up to retractable landing gear has reapplied itself into progressing toward ever-more-sophisticated instrument panels. Instead of saving up money to upgrade to a retractable, we just expend any spare funds pursuing airplanes with smarter avionics gear. Acquiring speed and good looks, it seems, are no longer the primary goals of aviation advancement.

That said, among some of us there's still a tempting desire to lift a gear retraction handle into the "up" position, feeling the gentle surge of acceleration from the stowing of wheels and struts. After all, REAL airplanes, like military fighter planes and giant airliners, have retractable gear. Some flight training academies even fit a faux gear-retraction switch and gear lights into the cockpit of their fixed-gear training airplanes, just to inculcate the proper takeoff and landing procedures for aircraft that will be encountered later in a student's career. Whether for ego gratification or skills advancement, there will always be a desire for retractable-gear general aviation airplanes.

First, let's talk about the reasons to avoid buying an airplane with retractable landing gear. The most obvious rationale is to avoid any possibility of making a gear-up landing. While often damaging both the aircraft and the owner's pride, a belly landing is expensive, both immediately and in the afterlife. The plane is going to be out of service for a considerable time while it's getting repaired, it'll cost a lot of money to make right, and the history of the machine is now tainted, no longer termed "NDH" in the sales ads, for "no damage history."

For an accident type that seldom has injuries associated with it, a gear-up landing is an expensive excursion. Belly skins, boarding steps, antenna, gear doors, cowl flaps and wing flaps will probably need replaced or repaired. Because the propeller bit into the runway, the engine will have to be torn down to ascertain the health of its innards after a sudden stoppage, and the prop blades will be toast. Retrieval of the belly-flopped airplane may cause further damage. None of this ever happens to a fixed-gear plane---well, almost never.

Looking at the cost of ownership, fixed costs will be greater if the aircraft's landing gear goes up and down. Insurance premium rates are set to cover the eventualities foreseen ("There's those that have, and there's those that will."), and the expense of maintaining and inspecting a retractable gear system has to be factored into the annual tariff of upkeep. At the very least, the shop has to put the plane on jacks during inspections, in order to swing the gear up and down and check all linkages. Gear motors or powerpacks have to be overhauled periodically, and there's wear and tear on bushings and actuators to be considered.

The airplane's utility is somewhat compromised by adding a fold-away gear mechanism. No matter how rugged the plane's design, taking retractable gear into an unprepared strip bangs its joints and bracing around. It just doesn't do to ask a spiffy, sleek retractable to serve as a bush plane, so you'll be wise to restrict its use to well-kept airports. Remember the design objective of a retractable-gear airplane---fast, efficient transportation. Because the wing is optimized for cruising flight, landing speed will be higher, thus the abuse suffered on rough ground is greater because of increased kinetic energy at contact.

There will be some lost payload with retractable gear, because you have to tote around a mechanism to power the gear's movement, with some extra parts required over a fixed-gear machine. And the space for stowing the gear requires some design compromises, like moving the fuel tanks or redesigning the engine installation.

Why, then, given the drawbacks, does anyone bother with retractable gear? Because it does provide more efficient cruise performance, by removing the drag of wheels, tires, brakes, struts and oleo linkages. If you're seeking 135 knots of cruising speed, you can either fly a fixed-gear Cessna 182 on 13 gph or a retractable Piper Arrow at 10 gph. A 200 hp Mooney delivers 155 knots or more, with the same fuel burn as the Arrow. Folding the wheels out of the way demonstrably boosts efficiency.

However, in the final analysis, a pilot trades up to a retractable-gear airplane because he or she wants it, much like choosing a low wing versus a high wing, or a Brand B rather than Brand P. If you really want the feeling of the gear thumping itself into the wells under your seat, you'll ignore all logic and buy a retractable.

The direct comparison between fixed gear and retractable gear is easiest to judge by looking at airplanes that are similar designs but with only the landing gear different. The 1978 Cessna Skylane and the '78 Skylane RG share identical airframes, but with a $16,000 difference in average list price, the RG delivered 14 knots more speed. The 1967 Piper Cherokee 180C and its same-year sibling, the original retractable Cherokee Arrow, gave a similar comparison. For $7,000 more money, you got 17 knots more cruise speed by moving up from the PA-28-180 to the PA-28R-180. Empty weight increases by 55 pounds in the case of the Skylane RG, whereas the Arrow's empty weight is 150 pounds greater than the Cherokee's, some of which is due to the addition of fuel injection and a constant-speed propeller. Similar comparisons can be made between the Cessna Cardinal and its Cardinal RG sister, or Cessna's 1983 172Q and the Cutlass RG, and Beech's Sundowner and Sierra sisterships. (And, please note, in most instances we're using manufacturer's POH speeds.)

The 21^st-century solution to maximizing cruise speed has been to use composite construction and place carefully designed fairings around a fixed-in-place landing gear. The Cirrus revolution concentrated on reducing drag with rivetless skin, a tight cowling, low-profile tires and minimal-clearance wheel pants. Such slipperiness paid off just as well as retracting the gear. Molding the fuselage and wings left next to nothing to disrupt airflow. American consumers constantly being more-is-better seekers of excess, the 200 hp SR20 was quickly eschewed for the fire-breathing SR22 and its turbocharged version, with half-again the horsepower. Cessna's 400-series (nee Columbia 400) took up the fast-glass challenge, and the cachet of retracting the wheels was soon out of fashion.

Even planes that predate the SR22 by a decade or more can be hopped up for better top end. There are numerous modification kits that can be appended to staid old fixed-gear airplanes, ostensibly delivering back much of the cruise speed lost from dragging the gear. Knots 2U in Burlington, Wisconsin, has some proven add-ons for Piper fixed-gear singles, concealing flap hinges and maingear disruptions along with control surface gap seals and extra wing root and tail fairings. Horton of Wellington, Kansas, offers Flight Bonus kits for Cessna 182s that clean up flap gap, brake and nosegear drag, direct descendants of the much-desired Siebel Skylane mods.

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Some years ago, I enjoyed flying Charlie Siebel's much-modified Skylane in a side-by-side comparison with a new Skylane RG. Mr. Siebel was a retired Cessna engineer who could see the potential for clean-up in the late-'60s 182, which had the old flat-spring maingear legs. His all-out streamlining efforts included fairing the blunt gear legs, the brakes and steps, the nosegear scissors and the flap gaps. He even added a brush ring to close the spinner-to-cowling gap and placed a floating asbestos doughnut around the exhaust pipe to seal that leaky opening in the lower cowling.

To see if all this worked, we lined up with a 10-year-newer Skylane RG and opened up both throttles; even with five extra-rated horsepower, the RG slowly slid back past our wingtip, proving that Siebel's labor wasn't in vain. The old fixed-gear Skylane did, indeed, top 180 mph TAS (156 knots) at cruise altitude. It proved to be a little difficult to slow it down for landing, particularly if we carried extra airspeed into ground effect.

When cleaning up stock airframes for speed, a few disclaimers have to be noted. First, don't expect cumulative speed increases; picking up seven knots from gear fairings and three knots from gap seals don't always mean you'll see a 10-knot increase by adding both. Next, some planes are just faster than others, depending on manufacturing tolerances and rigging. If you already have a comparably fast example, picking up advertised increases is not likely. And lastly, installing speed mods in locations requiring frequent removal for maintenance can create a real hassle for mechanics.

Folding up a set of draggy landing gears does take a big chunk of wind resistance off the airplane, and good, careful design work can result in a fast fixed-gear airplane. Whether or not you choose to go retractable, go for the most efficient flying you can afford. Me, I'm waiting for a retractable-gear Cirrus SR22, the SR22-RG, I presume.