Retractable Comm Antenna

All right, I *know* it's a stupid idea. But it seems like it'd be fun to
build.

I've got a Narco Escort II in my airplane. Like most (all?) Narcos, it
requires separate antennas for the transmit and receive sides. My airplane
has a ~25-year-old coax dipole antenna, and the "CW McCall's Revenge"
antenna I posted about a few years back. See:

http://www.bowersflybaby.com/stories/antenna.htm

I was flying today, and got complaints about the quality of my comm radio
transmissions. Back at the shed, I switched the transmit antenna to the
"McCall's Revenge" side, and a quick test to the Superunicom seemed to
indicate it was back to normal.

The older dipole may be finally giving out...not surprising, since its mate
did, three years back. It seemed to work OK on the receive side, but it's
obvious that I should put either some thought into a new antenna (or a new
radio that needs only one).

I *hate* external antennas. They're ugly. I prefer other options.

Jim Weir sent me some copper tape and some baluns for a new dipole, but I
recently installed a big metal inspection panel in the belly of the beast
(which is where I'd originally planned to mount the dipole) and it's too
tough to get into the tail cone to install it further back.

(Belly panel at: http://www.bowersflybaby.com/tech/belly_pan.html)

I was mulling over the possibilities as I started my car to head home.
Then I noticed the low-pitched buzzing noise: The car radio antenna
extending.

Why not build a retracting comm antenna?

My first thought would be to modify a car unit. Too bulky, too heavy.

My second was to *not* have a "collapsible" type antenna. I considered
just a rod that would slide out a small hole in the belly, but thought that
this would be tough to do with an ordinary whip...I'd need a long bar with
gear teeth to engage the motor.

My final thought was to go with a "hinged" type instead. Have a actuator
that rotates the antenna through 90 degrees... have it parallel to the
belly when the power's off, but rotates to vertical when power is applied.
Like a landing gear.

Anybody got some suggestions for sources for small 90-degree actuators like
this...or any other ideas for retractable antennas?

Ron Wanttaja