Pilot – June 2018

pilotweb.aero | Pilot June 2018 | 69

Feature | The slow-build Wot

admire it; it’s become invisible,
part of the workshop. What I’ve
been doing for probably over a
year now, is making wing ribs.

Wings
I made up a cutting list for the
wings several years ago and
obtained a quote from an aircraft
wood supplier, but thought it
only polite to check with my LAA
inspector first−he’s the chap
who has to sign for everything.
It turned out that he had wood
in stock and when he offered to
supply it at well below the quoted
figure, I said yes, despite knowing
that it would mean a delay. My
inspector has over sixty aircraft
on his books and supports a
number of homebuilders. He’s
highly respected and I’ve been
going to him for over half my life;
you could say we’ve grown up
together. If he has a shortcoming,
it’s that he can’t be hurried. But
then, I’m in no hurry myself. As
long as it takes is fine by me−as I
said earlier, I’m in the slow lane.
After a very long interval and
some prompting I had a message
to ring him. “The rib stock, is it
really 5/32 inches? That’s awfully
thin,” he said. I checked the
plans and told him that was the
measurement. “Hmm,” he said.
“My planer won’t go down to
that.” Between us we worked out

a modus operandi. He had lots of

offcuts in stock of aircraft quality

wood that I could saw into strips

and plane down to size, and B&Q

sold me an electric planer for

around 35 quid, that looked as if

it would do the job.

Some of the wood he gave me

came off a Hurricane project.

Other pieces were blocks of wood

that had been rejected because

of a knot on one side. All were

thoroughly seasoned and had

the required straight grain and

grain density.

I marked out an oversize plank

off the longest block−long

enough to make rib booms. Then,

very carefully, I ran it down the

band saw. Despite my care, the

cut was somewhat wavy, but not

too ‘off dimension’. I then took the

plank and marked out more lines

on its longest side, six of them,

again well over the required

dimension. This made six of what

Dr John Urmston described in

his book about building a Wot,

Birds and Fools, as ‘pea sticks’,

only oversize and of somewhat

uncertain cross-section. I laid

the six flat on the work bench

and ran the electric planer down

them, then turned them over

and did the same again. After

a few such runs, the pea sticks

had acquired the correct uniform

dimension and were straight on

two sides. Turning them through

ninety degrees and more planing

eventually resulted in six perfect

rib booms. It was amazing how

many of these one discarded

block of wood could produce. And

I felt so much more involved.

Dr John Urmston’s description

of making wing ribs is one thing

everyone who reads his book

remembers−the sheer scale of

production required. Thirty-six

nose ribs. Twenty-six full-length

ribs. Even producing one a day,

as he did, that’s months of labour.

He was a busy GP, so whipped up

a rib in the early morning, glued

and stapled it and left it to dry,

then glued biscuits on the other

side in the evening, after work.

But, as I think I’ve said, I’m in

no hurry. Far from producing

one rib a day, there were periods

when I averaged one a week. Last

time my LAA inspector came to

check out my (flying) Super Wot

for its Annual, I had eight nose

ribs and ten full size ones. Half

of them were a year old and with

winter coming, I had varnished

those, but not the others. (And

not the areas that will be glued

to spars, trailing and leading

edge.) He gave them a quick

look. “These seem okay,” he said,

twisting and flexing. “You should

see the state of some of the

factory-produced ones.”

Wing ribs and nose ribs –

Nick’s ‘small works of

art’ – begin to accumulate,

ready for the next stage of

the build

Very

carefully

I ran the

plank

down the

bandsaw