Sprucing Up the Airframe

March 27, 2008

Sweeps Update

Project Update: March 27, 2008

Sprucing up the airframe

By Ian J. Twombly

Past sweepstakes projects have sometimes neglected the airframe. It’s understandable when you consider we’re trying to address the paint, interior, engine, and panel in only one year. Since this year is all about Get Your Glass, we decided to expend most of our efforts on those work packages, and do only the necessary items on the airframe. Of course, that includes a few safety and speed items to sweeten the prize just a little bit more. Without a doubt though, some thoughtful past owners saved us time and money.

We’ve focused previous project updates on important airframe maintenance items such as skins and control surfaces. Williams Airmotive helped us out of a big jam again this year by providing a stabilator and two ailerons, both of which saved the maintenance crew at Oxford Aviation lots of time and effort. We also discussed a few options like Knots 2U’s baggage door strut.

In addition to the modifications and repairs previously discussed, we also added new tires, new wheels and brakes, new brake hoses, a few gap seals for speed, new wheel pants, and some other general fix-up items.

Making it easy

Regardless of how much or little to do to the sweepstakes airplane every year, there are some parts that always make sense to replace. Take the tires, wheels, hoses, and brakes as an example. Parker Hannifin, parent company of both Cleveland Wheels and Brakes and Stratoflex, helped us again this year with some new, reliable parts to keep the winner safe. Stratoflex manufacturers aircraft brake hoses, and Cleveland obviously does the wheels and brakes. We went new all around. Hopefully as a result the owner won’t have to worry about these items for years to come.

Of course, we would never change out the wheels, brakes, and hoses without also addressing the tires. Goodyear is back as a contributor this year with three new pieces of rubber. The additional grip we’ll get from new tires gives you a warm and cozy feeling when making those long cross country trips on unknown landing surfaces.

Piper also helped on the airframe side of the refurbishment with many parts that would have been extremely time-consuming and difficult to find elsewhere. The folks in the parts department sent us everything from new door sills to a rubber nose wheel bumper. Most of the parts are safety-related, but Piper has done its part to make the airplane look great, and we thank them for that as well.

Go fast

Let’s face it. A 1976 Piper Archer II is not a fast airplane. It wasn’t made with speed in mind. But there are things an owner can do to milk an extra few knots out it. Probably the biggest improvement will come from the new Speedpants. Laminar Flow Systems, a modification company that specializes in Piper parts, manufacturers the updated wheel pants. The company claims that testing has shown an average cruise speed of 10.5 miles per hour more than bare wheels and eight mph more than the factory Piper wheel pants. Since the airplane had bare wheels when we bought it, we’ll be looking for that 10 mph. Even if we don’t end up getting that full speed increase, the wheel pants do add a lot of aesthetic value, so the work to paint and install them was well worth it.

To help round out the previously applied aileron gap seals, we turned to Knots 2U. The company makes all kinds of different speed mods, and in addition to some much-needed fiberglass pieces, they also supplied us with some go-faster parts. Specifically, they sent their stabilator gap seals, which close the slot between the stabilator and the trim tap, and their wing root fairing kit, a small fiberglass fairing designed to bridge the joint between the fuselage and wing. According to the company, the result is an additional one or two miles per hour in cruise, better low speed handling characteristics, and reduced stall speeds.

But the real improvement in low speed handling will come courtesy of the Micro vortex generators from Micro AeroDynamics. Micro AeroDynamics says the VGs work by creating a vortex (spiral) airflow that better attaches the boundary layer farther aft on the wing. Because the resulting vortex boundary layer separates from the wing at a lower airspeed, the stalling speed is reduced and the airplane is more controllable at low speeds. Anni Brogran from Micro Aero says stall speed is reduced around 9 percent for the Archer, or down in the neighborhood of 40 knots indicated.

With all that we’ve put in to the airplane, there are a few things we didn’t have to touch, thanks to the diligence of previous owners. The airplane already had Skyflashers, a type of pulsing landing light and Whelen strobes. All in all, we hope you’ll agree that the winner will be left with a safe, fun, fast(er) flying machine.

Next week: The prop

E-mail the author at ian.twombly@aopa.org