Speed brakes, also called spoilers, have been sighted on everything from C-172s to Dukes and Cessna 421s. To a certain extent, theyve become a status symbol.
Yet, on some airplanes, you have to ask: When the heck would you ever use them? And on others, you might wonder why the factory didnt think of adding them in the first place. (Actually, brakes are a factory standard accessory or option on a number of new aircraft, including Mooneys, Bonanzas and the new Lancair Columbia.)
Thats all well and good for buyers of new airplanes. But what about the meat-and-potatoes of the gadget and accessory market, the retrofits? Are brakes a must-have item or just oneof those things to soak up some extra cash in the upgrade budget?
The truth is, you can get by without having speed brakes; it just takes good pilot technique and planning. On the other hand, certain aircraft can benefit from the capability to slow down and go down at the same time. Herewith is an analysis of speed brake economics and practicalities.
For many, the term speed brake or spoiler better describes what these things do to the flying budget rather than the airplane. In other words, these devices arent cheap, costing between $3000 and $8000 for the hardware, plus installation. And, of course, once installed, you arent done with them.
Like any other system, speed brakes require periodic maintenance and repair. There are also minor operational disadvantages. More on that later.
There are two types of systems out there, brakes and spoilers. Although the operating principles are somewhat different, both designs do the same thing, that is they pop-up a high-drag surface into the airflow, reducing lift and increasing drag or they simply throw a plate out into the wind, yielding pure drag, just the ticket for descending fast without exceeding redline speeds. The sidebar explains the difference between brakes and spoilers.
There are three suppliers of brake systems, Precise Flight, Inc., Spoilers, Inc., which markets under the trade name PowerPac and Thompson Aero, which specializes in two models of high-wing Cessnas.
Precise Flight offers brakes for a larger selection of singles and twins while Spoilers specializes mostly in twins but also has a system for the Mirage/Malibu series.
Many pilots who have flown with brakes swear by them and cant imagine how they ever got by without them. Yet before these things were available, we all did just fine without them. Its called pilot technique or, as one airline pilot said when a controller asked him to use his spoilers to meet a ridiculous crossing restriction, the spoilers are for my mistakes, not yours.
That said, some airplane can definitely benefit from speed brakes. Which ones? Speedsters, for one. Some airplanes just go fast. Cut the power and they still go fast. They dont come down, either. Remember the first time you tried to land a Mooney or Comanche? The airport fence dwellers thought you were practicing your slow flight techniques for the length of the runway. This type of aircraft fits the category of most obvious choice for speed brakes. Without them, theres not much choice for descents other than starting many miles from the destination and keeping the descent shallow to avoid overspeeding and/or engine chilling.
Where you fly may have something to do with the need for brakes. In the northeast or any busy airspace where ATC slam ducks are the rule rather than the exception, speed brakes can turn an unpleasant ordeal into an orderly, routine operation. When ATC calls for descents that build airspeeds quickly into the yellow arc, having boards to throw out in the breeze will give you an option other than unable.
Geography plays a role here, too. I fly a lot from the western states into the front range airports of Colorado. A common clearance is descend and maintain 8000 feet MSL from 16,000 feet MSL in a space of only 10 miles or so. This makes for a steep descent and may be undoable unless you drop the gear and flaps or have speed brakes. For those who need to descend this way routinely and dont like to put extra wear and tear on the gear and flaps, speed brakes may be worth the bucks.
Then there are the engine considerations: I once flew with a Cessna 340 pilot who had a home grown approach into a small airport in the mountainous west. It called for a power reduction from cruise power to 23 inches, dropping the gear and flaps and initiating a high speed descent from at least 16,000 feet to around 6000 feet. Not surprisingly, the airplane soon went into the shop with 10 out of the 12 cylinders cracked. Speed brakes almost certainly would have helped, allowing high power descents without worry about chilling the jugs.
Any aircraft that routinely cruises at around 10 KIAS higher than Vb or turbulent air penetration speed is a candidate for speed brakes. The general idea of turbulent air penetration speed is to prevent structural fatigue and eventual damage to, or failure of, the airframe and its various structures (engine mounts, baggage floors, seats and seat floors). To slow down quickly without having to chop power or toss the gear, speed brakes are nice.
Which brings us to our next point: Passenger comfort, including the pilot. Steep nose down descents and constant jockeying of the throttle generally makes for a more stressful flight, especially for nervous fliers. The ability to descend and slow the aircraft simultaneously without drastic attitude, power or configuration changes yields a smoother and more pleasant flight experience, especially for those who dont fly much or dont particularly care for it when they do.
In short, speed brakes can expand the operational envelope of the aircraft while keeping it within the manufacturers limitations. This may or may not yield a payback come resale. In some airplanes-say a Mooney 231-brakes are an absolutely desirable option and one airplane that has them may sell sooner than one that doesnt. But in a Cessna 182? Excuse us, but we dont see the point.
If theres a King Dog in the speed brake business, its Precise Flight. The company made its first systems way back in 1982 and now has the largest selection of brake kits for models ranging from the high wing Cessnas, through Beechcraft singles and into the Cessna twins.
Way back when, Precise Flight started with vacuum operated systems that used the ships existing supply to operate the brakes through a bellows and cable arrangement. This worked well enough but has obvious limitations, not to mention an occasionally high maintenance load.
Later, they evolved hydraulic designs for the Cessna 210 and Piper PA-32 series. These had dedicated pumps and motors and although they addressed the limitations of vacuum operated brakes, they introduced some problems of their own, namely the sort of nuisance stuff that goes along with any hydraulic system: Periodic pump work and leaks. There are still some hydraulic brake systems in the field on Pipers, but most of the Cessna 210s have been converted to electric designs. (The company still supports the Piper hydraulics.)
Precise Flight even dabbled in manually operated brakes for Mooneys. These were intended to be a bit cheaper than the vacuum or electric models but proved to be slow sellers. When the company ran into supplier problems, it dropped the manual systems.
All of Precise Flights modern systems are electric, using either a motor for each brake set or a single motor connected to both brake sets via a cable arrangement. These are so-called cartridge designs that slip into a slot cut in the upper wing and are activated by a yoke or panel-mounted switch. When the brakes are deployed, the two perforated aluminum panels project upward in an unfolding scissors motion, providing instant drag when the pilot needs it. When retracted, they stow back into the wings, with the slot barely visible.
Brake control is via either a yoke or panel mounted switch, an on-off arrangement. Punch it on for brake, punch it off to retract them. An annunciator light illuminates to let you know the brakes are out.
These arent like gear or flaps, by the way, where things kind of grind along for a second or two. Punch the button and they come out right now. Punch it again and theyre gone.
Precise Flight makes reasonable claims for its speed brake products, with claimed descent rates in the 1000 to 2000 FPM range, depending on aircraft model. In our experience, these are achievable without undue stress or unusual pilot technique.
The good thing about brakes in general is that they can be deployed at any speed up to Vne and with minor changes in attitude and power, the descent rate can be varied across a wide range. When you punch the brake button, you notice a slight rumble and vibration as the boards deploy but very little if any pitch excursion. Nervous passengers should be warned about the brakes ahead of time; the noise and vibration can be somewhat unnerving. Other than the relatively high cost, theres not much downside of speed brakes. With the Precise Flight system, however, one problem is flight in icing conditions. The sharp edges of the brakes milled surfaces make efficient ice collectors, thus Precise Flight warns against using them in icing conditions.
Nonetheless, we have, inadvertently. In a Mooney, we had one brake mechanism freeze in the extended position while the other retracted. That brake poking up in the breeze collected a minor glob of ice and this required about one-third aileron deflection to keep the wings level. Not fun but not terrifying, either. In a life-or-death icing event, a stuck brake might tip the situation over the edge but we have our doubts. The solution is simply dont use the brakes in icing.
On final approach, most pilots seem to stow the brakes once the gear and flaps have been configured, although some land with the brakes deployed. The concern here, of course, is that in a go-around, you could easily forget to retract them and suffer a metal bending loss in climb performance.
The truth is, you can take off with the brakes deployed and fly the pattern without noticing them much, other than slightly sluggish climb. At slow speeds and high angles of attack, the brakes arent especially effective. But as the speed increases, the parasitic drag they produce becomes a dramatic speed robber which is, of course, exactly the point.
Some pilots-and Precise Flight-claim that speed brakes reduce landing roll out, but for the average pilot, this may be hard to prove. The theory is that the brakes increase the stall speed a knot or two and thus put more weight on the wheels sooner in the rollout. Maximum braking is therefore more effective.
Pilot technique-and especially speed control on final-has much greater effect on landing rollout than does keeping the brakes out after touchdown, in our experience. The shortest roll outs result from the best-slowest possible-speed control on short final. Again, speed brakes arent all that effective once the flaps and gear are down and youre approaching the speed youll need for the shortest landing. The brakes will help get you to that speed, but once the trim and power are set, they dont offer much if any additional help.
As the name implies, Spoilers, Inc. sells…well, spoilers. These top-surface mounted plates are available for most Cessna twins and one single, the Piper Malibu/Mirage series. At the moment, Precise Flight has all of its twin Cessna and its Piper Seneca speed brake systems in redesign, so for all but the Twin Comanche, Spoilers is the only game in town for the multi-engine crowd.
Throwing the anchor out in a twin is not a cheap proposition by any means. The cheapest Spoilers system is the Aerostar, which retails for $6495. The Malibu/Mirage Spoilers set-up runs $8995 and the rest of the twins fall between these two, at $7495.
All of these systems are hydraulically operated and with the exception of the Aerostar system, which ties into the airplanes existing hydraulics, all have their own motor/pump units to power the spoiler. The entire unit fits into the wing itself, with the actuator inside the wing and connected to the spoiler itself through actuator arms. The pumps are mounted in the fuselage, a baggage compartment or locker.
When activated, the hydraulically powered arm pushes the spoiler up into airflow, instantly dumping lift from that section of the wing. When stowed, the Spoilers units fit flat against the top of the wing. Although hydraulically controlled, theres not a lot of plumbing running around the airplane. A single line runs to each spoiler unit from the pump but the actual activation is from an electric switch in the cockpit.
The Spoilers design is nicely failsafe in that in the event of an electrical failure, the solenoid valve controlling the hydraulics opens and releases the trapped pressure, retracting the spoiler. Furthermore, this trapped pressure design means that the pump itself runs only in short bursts to pressurize the system.
Weve flown the Spoilers system only in the Malibu and find that it lives up to its claims. Frankly, in operation, its not noticeably different from the Precise Flight units; pop the button, note the rumble and start the descent. Our impression is that spoilers are a little quieter but this could certainly vary from airplane to airplane.
The Spoilers systems do vary in one important way: Theyre approved for use in known icing conditions or, more accurately, on an airplane equipped for known ice, adding the spoilers doesnt restrict operation in any way via placard. The spoiler surfaces are far enough back from the leading edge to collect little if any ice and even they do, they lie nearly flat when retracted. So if operating in icing is a critical consideration, the Spoilers, Inc. products are worth considering.
As we reported in our previous examination of speed brakes, Spoilers has a unique installation guarantee with its 50 dealers. They quote a maximum installation fee so the owner knows exactly how much the install will cost, none of this we ran into problems and had to double the labor business. We like this approach and wish more companies would follow it in some form. Currently, most installs run $2200 but $2500 for the Malibu with radar pod and $2500 for the Aerostar. Because of escalating labor rates, these prices may be revised upward so check with Spoilers before committing.
Thompson Aero Products
One smaller player in the speed brake field is Thompson Aero Products, which markets only two systems, one for the Cessna 177 and one for the Cessna 210. William D. Thompson is well known in the Cessna community both for his books on Cessnas early days and for his extensive factory test flight experience. Thompson was involved in the design of the original Precise Flight systems and has retained some early design features, including vacuum only operation.The Thompson Aero system can best be thought of as a hybrid of the Spoilers and Precise Flight designs, in that it has both a top-mounted spoiler and a dive brake, which projects from the lower surface of the wing. (The dive brake is optional, Thompson, tells us, but is recommended for best performance.)
As shown in the drawing, the top surface has a wedge shape, which adds a bit of camber to the wing when the spoiler is stowed. Thompson claims this adds enough lift to reduce the stall speed by 2 MPH. (We have not verified this.) He says that this gives pilots operating at high density altitude airports a significant advantage by reducing ground roll on takeoff and, presumably, allowing a slower safe approach speed and thus reducing landing roll, too. Again, we havent verified this with flight tests or owner interviews. With only two aircraft covered, there arent a lot of these systems out there.
Thompson told us that the systems complexity makes its installation somewhat dicey, meaning that it could require 100 hours or more. It operates off either engine vacuum or ships pump vacuum; a shuttle valve picks the best source. A turbocharged aircraft requires a back-up vacuum system ($349) that does double duty as a back-up for the standard vacuum system. Other extras include a position indicating system for an additional $250.
Obviously, the Thompson system requires a pile of money, not so much to buy but to install, although it does boast the advantage of improving takeoff performance. Before considering the substantial investment this system requires, we would want to fly one first or at least talk to a couple of owners.
Buy or Not?
Do you really want to mess with these things? We think it depends entirely on the type of airplane and operations you fly. Some airplanes, notably Mooneys TLS, 252 and Ovation are somewhat of a pain to fly without brakes, which is why the TLS and Ovation come out of the factory with the Precise Flight system. But a pre-201 or a Saratoga or-gasp!-a Cessna 182? These are hardly the slickest airframes ever to come down the pike and our view is that pilot technique can certainly make them manageable in the descent, even when slam dunked.
If we had an older 182, for example, in need of radios and paint, we would tend to those items before opting for speed brakes. Your priorities may be just the opposite, however, and it is, after all, your money.
That said, on airframes where theres a choice-and at the moment, thats only single-engine Cessnas and the Piper Malibu-we think the Precise Flight systems are a good value and a nice compromise between cost and good design.
The Spoilers systems are also quite well-designed and made, but more expensive and we prefer electrically operated brakes over hydraulic, for ease of maintenance and reliability.
Also With This Article
Click here to view the Spoiler Checklist.
Click here to view the Brakes and Spoilers Specs.
Click here to view “Brakes vs. Spoilers.”
Click here to view Spoiler Addresses & Contacts.
-by Tom Ehresman
Tom Ehresman is an A&P and experienced test pilot for a major engine shop.