| Evening
Supercool,
I have spent the last three nights reading
all the stuff you have on your
web site. I find it very well writen and a good belly laugh
at times. In your
article "Powered Hang Gliders" you wrote "Thrust
works by increasing the mass flow through the propeller disc.".
That one little sentence says so much. For one it sent me
back to the one text book I trust "Elements of Practical
Aerodynamics" by Bradly Jones. The chapter on propeller
design starts off with
Momentum theory by R.E. Froude. Then on to Blade element theory
by Drzewiecki. And so forth. Was up till four in the AM reading.
Back to increasing mass flow. That explained to me why a plane
will start a takeoff roll slowly. Then as speed picks up propeller
thrust will increase, then more speed, more thrust,... up
to a point. Nature will not let you have something for nothing
as we all know. Also explained why we as mechanics saw on
a hot and humid night you could see Dowty Rotal props on the
YS-11's the air column behind the disc as the water vapor
truned to fog. Those big old props didn't develop thrust,
the blades beat the air into submission. So one of our training
instructors told us.
I showed the pictures you took of the Thunderscreech
as a gate guard in
Bakersfield, CA to my 84 year old instructor pilot (P-38 and
P-51 driver for the
AAF) today at the little airport where I have a hangar rented.
Darrel was one of
the volunteers that worked on the restoration of the F84H
at the National Museum of the Air Force (As they now call
themselves. We still call it the Dayton Airforce museum.)
Place has grown since you were there last. Added a third hanagr
working on a fourth hangar. Darrel has spoken with the test
pilot that flew the plane. The test pilot told Darrel that
if you stood in line with the prop while it was running on
the ground, afer a while you will become nauseous. Prop set
up some kind of harmonics that the body doesn't like. The
test pilot also said that the plane could only be test flow
way out in the desert. The prop made such a God awful noise
you could tell where the plane was up to 25 miles away. Stealth
it was not.
Darrel related that the Thunderscreech had been
on a pedestal in Bakersfield
since 1956. When the plane arrived in Dayton for its overhaul
the gearbox for
the prop was still dripping oil after all those years. Darrel
was in charge of
finding the insturments for the cockpit. He ended up speaking
with the retired
El presidente of Gruman. The Gentelman told Darrel that all
the drawings and
files for the plane were destroyed after the goverment stopped
the program.
Darrel worked from old photographs taken way back when. The
retired president told Darrel to speak with the test pilot.
He will know more about the plane.
Now about the plans for the Anna Domini. The
price you state, is that in AUD
or USD? I'm a bit confused. Will order a set of drawings as
soon as I know how
much to send you.
Regards, Erich
----
Evening Supercool,
Thanks for your email. You sure can post the
notes I wrote you. Just edit
the gramatical mistakes. The gentleman that worked on the
restoration of the
F84H is Darrel Larkin. Darrel flew PT-17's, BT-13's, AT-6's,
then into the P-38
for a hundred hours, then onto the P-51 for a thousand hours
in the logbook. His
father was a pilot in WW-I. His Dad trained in the JN-4 Jenny.
After the war
Darrel's father did research work in aircraft instruments,
and landing light
systems at Wright/Patterson Field in Dayton, Ohio. Darrel's
brother is a retired
engineer from North American Aviation (now Rockwell). Bob
Larkin was in charge of fitting the insturments in the panel
of the Apollo spacecraft. Quite a few interesting stories
there.
I was over to the Airforce museum just before
Christmas looking over the
Gemini spacecraft. I had just finished Mike Collins' book
Carrying the Fire on
his take of NASA. Darrel had lent me his copy. If you need
pictures of any of
the planes in the museum just holler. I'm only 45 minute drive
away from the
place. Gives me a excuse to make a trip and go through the
place one more time.
Now something completly different. This winter
I have been cleaning my
collection of model engines. I'll take one into work. Take
the engine apart then
soak it all day long in wing solvent (Jet-A fuel,left over
when we sump the
tanks) I will inspect the engine parts under a ten power magnifiying
glass. I
noticed on the back side of the cylinders the is more castrol
oil deposits in a
gum burnt state. This is saying to me it's hotter on the back
side of the
cylinder than the front side where all the air is. That started
me thinking
about building cooling baffels for these little engines. So
I'm reading away in
your site. Read the article about ducted cooling of small
engines. Well, you are
light years ahead of me on the subject. I like what you have
done. Bet this is
the best advancment of engine performance in years. I don't
have a mill so my
solution will be to use thin sheet aluminum.
Shipping the plans for the Anna Domini. I work
for the freight airline ABX
Air, who's biggest customer is DHL. Let me see what I can
do from this end about shipping the plans. Will the plans
be folded or rolled in a tube?
Take care, Erich
----
Evening Supercool,
The test pilot for the F84H is Henry G. Beaird.
Darrel told me today he is alive and well living in Dallas
Texas still flying Lear Jets. A short bio of Henry Beaird
can be found here www.southernmuseumof flight.org/AAHOF_Beaird.html
Good reading.
Take care, Erich
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