Young pilots flying fast military aircraft need ejection seats
to fling them away quickly if problems occur.
But us old guys flying slow homebuilts sometimes need ejection
seats, too. Aging is a slow foe; things feel OK
forever, but suddenly you realize it’s caught up and you’re
Take my case. For twenty-five years, I’ve been lifting
myself vertically out of the open cockpit of my Fly Baby with a
combination of arm and leg leverage. But knee problems
took one leg out of the mix, and made the first few inches of
lift difficult. I had to brace myself on one of the rudder
pedals with my good leg, and I didn’t like the extra
wear-and-tear on a control system.
What I needed was an ejection seat. Not a youngsters’
rocket equipped Martin-Baker to fling me over the hangar roof,
but a much slower one that would boost me those first critical
What to use, then? I looked at scissor-lift tables, with
an eye towards adapting the lift portion to the Fly Baby
cockpit. All were too big and too heavy
Inspiration finally struck: What about those lift chairs
for the older folks? Could I adapt the lift mechanism to
Up She Rises
I stopped by a local medical supply store, hoping to examine
some of the mechanisms used by the seats. Instead, the
manager showed me the Uplift
Technologies Power Seat
. The Uplift is a single,
self-contained package that is designed to be placed atop any
type of chair, plugs into a wall outlet, and lifts and lowers
the occupant about eight inches. It’s designed to be
portable, so the weight is low enough to allow a senior citizen
to carry it around.
It was a perfect solution, with no need to disassemble and
attempt to modify the mechanism. But I was concerned about
the length. Would it fit in the available space without
interfering with the control stick?
I confessed my potential use, and my concern about length, to
the store manager. “Is your plane at the airport just down
the road? Take it down and see if it’ll fit!”
The Fly Baby has an extremely basic seat interface…just a flat
framed area in the cockpit floor. The Uplift’s flat bottom
lay atop it without a problem, and the length and width were
I couldn’t resist. I ran an extension cord to the cockpit,
plugged in the seat, and hopped in. A flick of the lever,
and the seat rose smoothly, letting me easily grab the cockpit
sides to push the rest of the way out.
Back to the store, plastic on the counter, and $150 put me in
possession of the seat.
The power cord was a problem, of course. My initial hope
was that I could replace the motor with a 12 volt DC unit.
Access the motor was easily achieved, but finding a 12 volt unit
that would fit the same mounting holes and carried the same gear
on its shaft would be problematic.
My fallback was an automotive inverter. Many companies
sell units that plug into a car’s cigarette lighter port and
supply wall-plug power to electrical gizmos. Some of these
can be purchased for $20 or less.
How big an inverter? The Uplift seat is rated at 120 volts
and 0.6 amps, or about 72 watts. Considering
inefficiencies of the inverter, a 200 watt inverter seemed the
minimum size. Fortunately, it only runs a few seconds per
Research unveiled an issue when using an inverter to operate an
appliance with a motor. The cheap inverters produce a
square wave, fine with most electronics (which convert it back
to DC anyway) but motors can’t use it. Units producing a
sine wave are a bit less common and more expensive.
I found a 200 Watt inverter with a “Modified Sine Wave” output
for about $45. A quick test with a battery showed the
power was acceptable to the seat.
The initial plan was to place the Uplift directly atop the
existing seat-mounting frame, adding just a few brackets to keep
the seat in place. A bit of consideration, and I
reluctantly abandoned that approach. The frame would have
concentrated the weight into narrow portions of the seat base,
and I was concerned the plastic would eventually crack.
Instead, I used a piece of ½” plywood, like the stock
seat. A wood frame on the underside of the plywood
fit inside the seat-mounting frame to hold the unit in place.
The inverter had a flat
mounting surface with small feet. I installed it
upside down (e.g., an inverted inverter) below the plywood,
held in place by stainless-steel hose clamps (with padding)
through holes in the plywood panel. The top of the
plywood was shallowly routed out so that the clamps sit
flush with the surface. The surfaces were curved
and smoothed with chisels and sandpaper to avoid stress
points on the hose clamps.
With the seat in the full-rise position, access to the
inside of the plastic exterior shell was easy. A Molex
connector was installed on the outside of the shell for
power, as was a combination switch/circuit
breaker. A bit of bench testing showed a ~4 amp
draw, so I used a 10 Amp breaker left over from a recent
Testing showed that the inverter drew about a half-amp even when
not running the seat, so I didn’t want to leave it running all
the time. Plus, I suspected it might induce a lot of
garbage into the aircraft’s electrical system, and I did not
want to have the avionics exposed to it. There’s probably
little risk, but I didn’t feel like betting that my $45 inverter
wouldn’t blow out a $2,000 transponder.
For a reminder to turn off the power, I added a piezo buzzer
from Radio Shack. Connected to the inverter’s output, it
beeps loudly whenever the inverter is powered on.
My recent electrical system rebuild included an avionics master
switch, so I make sure to have it “off” before turning on the
inverter. Had I planned the seat during the rebuilt, I
would have used a DPDT switch for the avionics master, to ensure
the seat could not be powered-on unless the Avionics master was
off. I could install a small relay to perform the same
function, but I’m content with handling via checklist for now.
The seat works. Turn on the aircraft master switch, verify
the avionics master is off, and flip on the seat-power switch
and hear the beeper. Pull the seat lever up, and the eight
inches of rise makes it easier to clamber out of the cockpit.
The seat runs a bit slower on the inverter than it does on
wall-plug power, something research had mentioned. It
takes about 25 seconds for full rise. It’s a subtle
motion, not really apparent other than my adjusting position in
the cockpit as the sides drop away. One friend said, “You
looked like you have a bad case of gas.”
Here's an animated GIF of the seat. Actual time for the
rise is about 20-25 seconds
Back to the Back
When I first flew with the power seat, I had a temporary back,
consisting of just a flat sheet of 1/4" plywood. Most
anyone who's flown with a stock seat knows how uncomfortable
that straight seat-back is. I could have just added a
half-mile of foam, but that robs legroom...which is at a premium
in my bird.
The final seatback was going to utilize the Wells Seat Brace
I installed a couple of
months back, so the problem with a flat sheet probably wouldn't
be as bad. Probably. But I still thought I needed
just a little curve in my seatback.
First thought was to find some really thin plywood and laminate
a curved back. A bit of research kind of scotched that;
certainly do-able, but really thin plywood wasn't commonly
available around here, and pretty darn expensive when one goes
to the online sources.
Second thought was to cut a whole bunch of parallel slots across
the back of a piece of 1/4" ply, until it was flexible enough to
take a curve. Then fiberglass the back to lock the
I tried that one, first. Set the table saw to cut through
all but one ply, then use the ruler on the saw to space slots 1"
Relatively quick to do. However, when I tried to bend the wood,
it still didn't want to go. When I bent it TOO far, there
was always one slot that would fail (break) and then the thing
wouldn't take a smooth curve for love nor money (the broken line
would always be a sharp break). Tried three times, none of
they would work.
Hmmm. Back to the lamination idea. I checked with
the local wood stores and found a nice big piece of 1/8" birch
ply for a reasonable price.
I'd need a form to bend it on and clamp it down to. I
considered cutting out a set of arcs in 3/4" ply, nailing them
down in parallel, then covering the thing with some scrap
Then I remembered my failed "slotted" plywood. I used a
nail gun to tack a 2x2 across the middle of a piece of heavy
plywood (actually two 1x2s) curved the slotted ply across it,
and nailed the ends of the slotted ply down. Tuck a couple
of 1x2s midway to the ends, and I had a form. It had
a little discontinuity at the broken slot, but I figured the
plywood would just curve past it.
Next, I covered the whole thing with wax paper. Then I
clamped down one piece of 1/8" ply 1'x2', covered it with glue,
then slipped another piece of ply atop it, removing/reattaching
clamps as necessary to get the two pieces together
After 24 hours of glue-cure time, I cautiously removed the
clamps. It worked! The two pieces of plywood held a
nice gentle curve.
Now, where should the curve go? I had marked on my flat
test plywood where the most pressure had been on my back.
I adjusted the new curved back to put the apex of the bend at
that spot, then cut it to fit.
As you can see, it really is a gentle curve. You can also
see a circular hole near one end of the back. This is a
"finger hole" to give me some way to hold that end of the seat
A test fit in the airplane showed it fit within the inlaid area
defined by the Wells brace. I threw a bit of 1" temperfoam
atop it and sat down. No "hard spots" like the flat sheet
had had, however, I could feel the ridge of the bulkhead very
slightly. The 1" temperfoam wasn't quite enough.
...I was feeling the bulkhead/foam interface area on top).
I figured a piece of normal 1" foam would take care of the
To hold everything in place, I needed some upholstery for the
seat back. It seems like every ten years or so, I need to
make a new seat cover for some reason or the other, which means
I have to re-remember how to use my sewing machine.
("My" sewing machine for a good reason: It was a birthday
present for my wife, the first year we were married ~32 years
ago. I got smarter after that. In any case, I'm the
only one who has ever used it, always for Fly Baby seats.)
Off to the fabric store, always a fun time for an American
male. I fight the overwhelming urge to only pick up
camouflage cloth ("See! See! I'm a macho man!") and poked
through the solid colors. I found a nice black heavy-duty
cotton and bought a couple yards of it.
(All right: Gotta insert my favorite fabric-store story
here. Years ago, the store I went to was right next door
to car-parts place. As I arrived, I saw two young guys
trying to get their car started. It was backfiring all
over the place. I leaned over, offered some totally
useless advice, then continued into the fabric store.
Which was empty. What the heck? Then I saw a woman
in the far back of the store, peeking around a doorway.
Then the car outside went through a series of backfires again,
and I realized what was up: "It's OK folks...it's just car
backfiring next door. And about a dozen people came back
So any, I got the cloth, dug the sewing machine out of the
garage, re-read the instruction book again, and got to
work. The basic design would just be a bag, slipped down
over the foam and wood and secured at the bottom. Think of
a "U" shape, with the bottom of the "U" being the fabric folded,
and two lines of stitched applied on either side.
I cut my fabric in half, giving enough for two covers. I
folded a piece in half and stitched down one side. Then I
tucked ONE piece of foam and the wood back into the half-bag,
laid it flat, tucked the fabric tight, and laid down a chalk
line for the other side. I used only one piece of foam,
hoping things would be nice and tight when both were installed.
(Rumors that I wore an apron to match the tablecloth are totally
But when I sewed the next seam, I actually put it about a
half-inch inside the chalk line. I had enough to do a
second cover, if needed, and I wanted to fabric to be tight.
Then...try to assemble. Surprisingly enough, my eyeball
by-guess-and-by-golly method worked great. The foam fit
tight, but it did fit.
Bolt the seat back to the piano hinge on the base, and take it
out for a
This is actually a bad picture, the seat back is on top of the
shoulder harnesses and so it doesn't fit straight in the back
like it should.
Plug in the power lead and sit down. Pretty
comfortable. Hit the master, turn on the seat power, and
hit the "eject" button. Rises up normally, and getting out
is a bunch easier.
The Bottom Line
The bottom line was surprisingly reasonable.
Cost? Less than $250, including the seat, inverter,
buzzer, connectors, and associated wood and fabric.
Weight? The seat-lift mechanism itself weighs 12 pounds,
and the inverter was less than a pound, plus a pound or two for
the wood and other bits. But my old seat was surprisingly
heavy, and the net weight gain was only nine pounds. The
simple operation of the seat, including its dirt-simple
flat-bottom interface, would probably suit it for any number of
Eventually, a fancy new store-bought knee is probably in my
future. Hopefully, my “Moron-Baker” ejection seat will let
me keep flying until then.