Plane & Pilot
Tuesday, September 21, 2010

Artificial Speed


Believe it or not, there are some easy, inexpensive ways to fly faster



GO FASTER Bill Cox has added many speed modifications to his Mooney.
It’s probably the most common question I hear at air shows and conventions such as Sun ’n Fun, AirVenture, AOPA, NBAA and Reno. “How can I make my airplane fly faster?” While it’s true that more speed isn’t the only goal of pilots, it’s certainly the most popular one. Like many new pilots born without a silver spoon, I rented for a year or two, then started my chain of aircraft ownership with a comparatively inexpensive and slow machine—an entry-level, two-seat, Globe Swift GC-1B. It looked fast and sexy, but it wasn’t—maybe 110 knots on a good day. Fun—yes; fast—no. Then, there were two Bellanca Cruisemasters, followed by a new Mooney 231. A partnership on a Seneca II was next, succeeded by my current airplane, a used Mooney Turbo Executive. The fastest of the group was probably the 231, capable of 180 knots TAS at 18,000 feet on a good day.

My current Mooney is a great little airplane, and I’ve spent the equivalent of its book value all over again on speed mods. So far, I’ve picked up a total of 14 knots in cruise speed by installing a LoPresti cowling, 201 windshield, Power Flow exhaust, gap seals, flap and aileron hinges, and plenty of other stuff I’ve forgotten. That extra speed has demanded 20 years of work, and yes, I’m aware I’ll never get that investment back when (if) I decide to sell.

Fortunately, whether you fly a Mooney or a Cherokee, you need not spend a huge amount to realize maximum cruise speed from your airplane. There are at least a half-dozen things you can do to optimize your airplane’s performance that are basically free. One or two other items will cost you a few bucks, but the results will be well worth it.

One thing I’ve been taught in campaigning the Mooney for more speed over two decades is that speed improvement is a game of inches. Each minor change may be worth only ½ to one mph, but put them all together, and the result may be a significant drag reduction. Also, keep in mind that speed improvements will most often result in a percentage increase. What may generate a full knot on a Bonanza might be worth only half to three quarters of a knot in a Skyhawk.

The first and perhaps simplest improvement to increase cruise performance is to minimize empty weight. You obviously can’t manage payload for the purpose of increasing speed, but there may be some things you can do to reduce the airplane’s weight before adding fuel, passengers and baggage.

A few years ago, I discovered I was carrying around many pounds of miscellaneous junk in my Mooney. There were as many as six cans of oil in the baggage compartment, two or three extra headsets, three Oshkosh tiedown kits, an extra tool kit, two or three kneeboards I never used, several old copies of the AOPA Airport/Facility Directory, approach plates and Low Altitude Enroute Charts for the entire USA, four life vests for trips around the arid Southwest, an old life raft that hadn’t been repacked in 10 years, and things like that. Traditional wisdom has it that every 100 pounds you lighten the airplane (in the standard range of general aviation singles between 2,400 and 4,000 pounds) result in about a one-knot speed improvement. In my case, I dropped perhaps 40 pounds of junk, so I realized about half a knot.



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