Saturday, October 31, 2009

Sidewinder on Steroids

Here's yet another gem I found at China Lake Alumni.
1970 gallery.  It's called the HAP Sidewinder. HAP
stands for High Altitude Project.  The limited research
I found indicates that it was created by combining a
Sparrow rocket motor with the front end of an AIM-9L.  
Some test flights were performed, but the project was
soon cancelled.

I've never been a big Sidewinder fan and the
proliferation of variants has always made the study of
them a bit bewildering.  Having admitted that, I must
say;  I LIKE THIS!

I can look up the 2 diameters and easily scale a drawing
from there.I have an Estes Python nosecone which will
serve for the Sidewinder seeker section,  or I can turn
one, as well as turning the transition section.  
Sigh... just add it to an already long list of unstarted
and semi-started projects

Monday, October 26, 2009

Playing with a Stubby Euphemism

3d by Dick Stafford

Photo KeithAlanK

Photo KeithAlanK

Photo John Lee

I can appreciate a clever euphemism.
The USAF nuclear arsenal is typically modular in nature. A sensible
approach when technology is progressing rapidly. The nuclear
explosive is a seperable unit from it's carrier body, either a
missile or a gravity bomb. In the case of a gravity bomb, the
body is referred to as a drop-shape.   Cute, I like that.

This it the DS-3r; Drop Shape, 3"dia, rear ejection. This is also
the 3rd DS that I've built over the years. Won't be the last either.
I had been sketching and dreaming this particular design for a
couple years already, and when Giant Leap introduced it's 3", 5:1
plastic nosecone, I knew the time had come.  I turned an upscale
Cherokee cone for a rocket buddy in trade for the Giant Leap

I always thought the slo-mo vidclips of gravity bombs with retard
packages looked cool. The small close coupled chute ejecting out
the rear to slow the bombs down. For a low altitude drop, this
gives the aircraft a lead over the slowing bombs so that they
don't explode directly under the aircraft. Nukes often are
configured the same way for the same reason, despite much
higher release altitudes.  The DS-3r has the internal space to do
this well. The motor mount tube extends well into the nose. The
ejection gasses must 1st go forward, then return through the
baffled centering rings to eject the tail cap and the chute which
is packed around the motor. This utilizes the entire internal
volume of cool air to push the chute out before any hot gasses
can even reach it.  Another trick I pulled is that by removing the
nose cone, the entire motor mount/baffle assembly slides right
out for servicing or for chute replacement.

When the DS-3r was nearing completion, I decided that It
needed to be run through RocSim.  I've used it a time or two,
but don't have it.  I still use Barrowman CP calc on paper, and
did it this time, though knowing that it has trouble with rockets
this stubby.  I contacted Dick Stafford of Dick's Rocket Dungeon
fame and he helped me out. After tweaking the mass and balance
in line with the the real model, he found that only one ounce of
nose weight would be required, I added 1 1/2oz.  RocSim
Barrowman CP agreed with paper Barrowman CP, and RocSim CP
was indeed a bit further back.  The wedge airfoil fins [which
RocSim as yet doesn't handle] actually moves the CP still further
back a bit.  The performance sim crosses Estes motors and the
24mm Blackjacks right off the list, too slow off the rail.  E18W is
good for 800ft, the F39T goes to 1200ft.  Just about perfect
upper range, and I may work my way down the motor list over
time.  That new Aerotech E20W looks nice too.

Tuesday, October 13, 2009

China Lake YouFoe Quiz

Here's another pic I found at China Lake Alumni.
The very first pic in the 1962 gallery.
I haven't seen one of these in at least 20 years.
I do know what it is.
Do you?

Sunday, October 11, 2009

Mystery Mono at China Lake

Sometimes it pays to repeat a search from time to time.
Previously, when I Googled Monocopter I'd get some of the
usual scattering of model vidclips and discussion, and a whole
lot of that Euro turbofan jetpak, which may be mono, but
aint no copter.  This time around the photo below popped
out at me.  Quite a find.
It was at the China Lake Alumni website, in the photo gallery
page for 1963. China Lake is home to the US Navy weapons
test facilities.  The site search engine, unfortunately, yielded
no other photos or info. I kept the original file name on the pic;
Monocopter perch 16AUG63 CLK SL-027985

I am able to infer a few things from the pic. Foremost is that 
the protuberance on the far side of the hub is not the same as
the wing on this side, so I believe this really is a monocopter.  
The wing is mounted to the hub at the center of lift, therefore  
is probably capable of changing pitch in flight, likely in response
to control inputs to the elevon at the wingtip. If the hub isn't
made from actual truck hubcaps I'll be surprised as hell.   If it's
heavy enough the disk hub will stabilize a rotor despite the lack
of a proper flybar.  I had already designed a monocopter using
a ring shaped hub, although the ring on mine is proportionately
larger in relation to the wing since it'll have no extra internal mass.

Two things are puzzling.
Obviously; what is the powerplant?
The other is the source of the 1/2 round shadow directly below
the hub? You can see that the sun is to the left and the shadows
are stretching to the right, therefore the hub's actual shadow is
to the right as well.

If anyone knows ANYTHING further, PLEASE comment!

Saturday, October 10, 2009

Low Flight 2, The Heli Version

Today, while surfing the web for something completely different,
I ran across another version of Low Flight, this time written by
and for helicopter pilots.  I previously posted the original High Flight,
and then Low Flight written for Phantom II crews earlier this year.

Low Flight

Oh, I've slipped the surly bonds of earth
And hovered out of ground effect on semi-rigid blades;
Earthward I've auto'ed and met the rising brush of non-paved terrain
And done a thousand things you would never care to
Skidded and dropped and flared
Low in the heat soaked roar.
Confined there, I've chased the earthbound traffic
And lost the race to insignificant headwinds;
Forward and up a little in ground effect
I've topped the General's hedge with drooping turns
Where never Skyhawk or even Phantom flew.
Shaking and pulling collective,
I've lumbered the low untresspassed halls of victor airways,
Put out my hand and touched a tree.