Moonburner Motors Get Bent

First time I've tried to upload a vid clip.
Hope it works OK.


When I first started experimenting with making my own sugar motors, I made several decisions under their own merits which eventually lead to an epiphany. When combined, these factors
created an interesting moonburn synergy.

First, I chose to use 15/16" diameter [24mm] phenolic cases that are thicker walled, than Aerotech, being 3/4"id instead of 7/8"id. To simplify the nozzle issue, I elected to buy Aerotech nozzles instead of producing my own from scratch, though this requires that I turn down the nozzle OD to fit my cases. Like most other experimental motor makers, I still wanted to maximize the propellant fraction. I decided to pour directly in the cases, including the convergent frustrum. No casting tubes or liners required. After only a couple false steps, I tried silicone tubing as my core spindles, which works great when casting sugar propellant. The silicone spindles are longer than the motor case, and extend all the way from the nozzle to beyond the top end. A rod or dowel, as the case may be, the same diameter as the nozzle throat, but loose inside the silicone, extends through, acting as an alignment guide and throat plug. After curing, the rod is drawn out, then with a steady tug, the silicone stretches, losing contact with the core wall, and pops right out pretty as you please.

Though I started with core burners, a major goal all along was to make moonburners since I couldn't buy any commercial ones for a long time, and then when I could, only in 'J' and above.
With the old Aerotech D-G moonburners, the fuel was precast and had a drilled port to one side that you would have to blindly hunt for with a piece of 'S' bent Thermalite. Even for
someone experienced with these motors, it was tough to install, tough on the Thermalite and chuffed too often at the best of times.
Epiphany; My flexible silicone spindles need not be straight. I attached the silicone tubing to the nozzle throat with a short plug, then 'S' turned the tubing over to the case wall where
it's held in place with a suitably fashioned wire clip. This creates a smooth pathway for the ignitor during installation AND expulsion, even when using Copperheads. This 'S' turn also creates a short area of coreburn configuration near the nozzle, producing a higher takeoff spike before it settles into full moonburn mode. Perfect for a medium size 'D'-'E' bird.

Another goal of making motors was that my wife [now ex] and I had always been into clustering, especially air-starts. Estes 'D's are great for this but keep costing more and more.
I was already enamored with the idea of focused thrust [long before Flis-Kits] and wanted a way to add that feature to already existing rockets with air-start clusters. The curvy silicone core spindles work even better with the angled nozzles. Now there's only one shallow bend instead of an 'S' curve. This also reduces the coreburn section, making the motor more of a true moonburner. Since classic moons ramp up and down more gently than other motors, they are less prone to affecting the flightpath if multiple ignitions are uneven, or lacking. Focused thrust, of course, further reduces possible flightpath disturbances. I made a 10 degree angled nozzle holder for my lathe, so that I could modify the Aerotech nozzles before gluing them into the cases.












Angled lathe tooling with unmodified nozzle
installed, and a used angle nozzle motor.

Campitch 1 Monocopter Pt 3

A good ascent. Note wing gap.

Takeoff. Sign of an inadequate flybar.
1 ft up and already 1 ft sideways.

The wreckage.

The Campitch 1 is no more.

It made 10 flight attempts in 10 months.
Four flights were considered OK, one was very good,
and only one was nearly perfect. One way or another
it tossed it's wing four times. It tore up one part  or
another of the cam system four times, and broke one
flybar. The final flight did all three at once.

Even the best flight bent the cam follower bolt.  It
was the ninth flight and I used one of my 24mm E  
sugar moonburners.  It ascended to around 60 feet, it's
highest flight, and when it coasted about halfway down
it finally slowed enough to retract the wing into full
autorotation mode.   D motors never gave it the needed
height to do this.

On the tenth flight, I used an Aerotech E11J. At about
the 40ft mark, still under power it disintegrated. The
flybar was broken and the cam follower bolt was half
torn from the wing root, and the bolthead was pulled
through the G10 fiberglass cam track.

This spinny thang taught me more than all my previous
monocopters put together.

The biggest problem the CP1 had was it's pretty wing.
Being fully glassed it was too heavy [especially with
balance weight added to the leading edge], and that
eliptical wingtip made it too slick. Together this
gave it a higher than average rpm AND a tendency to
not slow down anytime soon.
Again, because of the wing weight, the unweighted
3/16" flybar used on the first five flights lacked authority.
This caused the motor and wing to pick their own pitch
angle and for the monocopter as a whole to squirrel
around and track at odd angles instead of going straight
up. The second flybar was 1/4" diameter and slightly
longer, but it had so much drag  altitude was reduced
by half.
The wing retract spring is always an issue. If it's too
heavy; it takes extra rpm to extend for takeoff.
If it's too light; it has to slow more to retract into
auto rotation. I used springs because I had a pile to
pick from. A better solution would be rubberbands
which might be easier to fine tune.
Finally, 1/8" pultruded carbon tubing it totally
unsuitable for D+ powered monocopters.  I managed
to break them outright 4 times, in three different
applications.

I'll spare y'all the flight log.
Yahoo Monocopter Group won't be so lucky.

Sugar Motor Testing Pt.2, Getting Sweeter

t
Art Applewhite's Cinco38 Prototype
Pizza Hut

My Tide Wave version with ISP
38-360 case for comparison

Tide Wave on 1st sugar flight.
Using Ultra-White recipe.

Tide Wave pouring on the sugar
and spinning hard.


A big update to the previous post.
Since that test took place back in February I've burned 3 more sugar reloads in the test series. Since the test stand is still broken [the new guage I want for it aint cheap], I went ahead
and flew them in an Art Applewhite 38mm Cinco Saucer clone, my Tide Wave, or in Art's prototype Pizza Hut Cinco38.
Since it's 1st flight I've trimmed down the wavy edges twice on the Tide Wave. The spin under power was fine by me, but the spinning causes recovery problems. I've also flown the Cincos on an Aerotech G64W reload and an ancient and suspicious single-use Aerotech 320Nt H145 manufactured in 1988. These 2 motors definitely bracket the sugars below in the medium H category.

The motor that blew the stand had Bi-modal KNO3 [an inspecific mix of powdered and granular], my usual opacifier 1% Lamp Black, plus 1% Red Iron Oxide. A very fast recipe.
The next 2 are the same as above but with 8% Titanium shavings added for sparks. One had fine sparks, the other coarser sparks. The mildest recipe, nicknamed Ultra-White, uses granular KNO3 and 1% Titanium Oxide as a white opacifier. The only test recipe not burned yet is Ultra-Pink. Same as Ultra-White above but with the addition of 1% RIO on top of the TiO2.

So far, except for the wrong nozzle incident, everything has worked well. Ignition with my now standard Copper Thermite ignitors has been a non-issue. The RIO sure is messy stuff but it
really does improve pouring viscosity, just as other sugar cookers have noted. I didn't doubt it, but wow, seeing it happen is amazing.

At this rate, I'll have to make more test loads by the time the test stand is repaired.
Aw shucks.

Sugar Motor Testing [not all sweet]

Ignitor hookup.
Black crescent at bottom of guage
window is probable damage.


Instant On! Ignitor wires inflight,
Guage needle is still on zero.


Burnout. Foreground smoke
came out of guage face


Expelling a bit of casting tube.


Blackened guage guts hanging out.


In order to evaluate possible changes to sugar motor recipes, I developed a new shorter motor that would be more economical to operate. It helps that I was given a damaged reload case [Thanks Ray!]. My long motors use two 6 1/8" fuel slugs, unfortunately the short motor, after repair, only fits 5 1/4" of fuel. An even 50% would've been nice, but this is close enough, and it was a free motor.

Late last year I made 4 pairs of reloads, all physically the same, but each pair has a somewhat different formula. All are moonburners since they burn twice as long. Eventually some will go to a thrust stand, but IMO, chamber pressure tests are initially more important. It's good to know what even works before tieing up [or risking] a high dollar digital thrust stand.

I made a new nozzle with a 3/16" throat that would be used with some of the new grains, especially the baseline formula. Being virgin territory, none of these reload kits have the
nozzles listed on the labels like I do with the larger mature reloads. On Feb, 20 2010, the morning of the test, I picked the new 3/16" nozzle and installed it with reload #1 rather
than with reload the mildest. Reload #1 was a hotty and should've been tested first with a 1/4" or even 5/16" nozzle. The motor survived the test but barely. Probably only because it trashed the guage and was blowing out both ends. As it is, it severely belled the nozzle washer and crumbled the corners of the nozzle where it was pressed into said newly angled washer. Despite the short foliage and limited dipersal angle, we never did find the polycarbonate guage window. There is evidence that the pressure guage was damaged previous to this test attempt.

The hydraulic test stand has been cleaned and is getting rebuilt. Besides the new & better guage, it's getting a grease fitting and a brake bleeder valve. Instead of filling the stand with brake fluid as before, I'm going to use grease. This will allow for easier transport of the stand and with a good grease gun I should be able to use the stand to pressure test motor case materials and other components.

A Classy Ride

But pretty it aint.
The Bell X-14, I want one!
Can anyone name another jet powered aircraft
with an open cockpit?
I suppose it's just as cool that the X-14 is a VTOL,
but I like the open cockpit best. I want to take it
to the coast and wave to the girls as I cruise slowly
just off the beach, scarf trailing behind.
Surprisingly it would go 172mph and reach 20,000Ft,
brrrr, it's cold up there!  Well, not too surprising,
any plane that can VTO has power to spare.  Range
was 300 miles. Corpus Christi here I come.

The X-14 was built on the cheap in 1957 using  
Beach Bonanza and T-34 Mentor parts. Vertical
lift is provided by a belly mounted flap that
vectors the dual jet exhausts downward. Bleed
air from the engines to puffer vents at the wingtips
and tail provides control in hover.

Good news, it's being restored at a museum in Indiana.

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

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!

Blue Tube Advancing the Rocket Hobby

The Blue Phenix 4.0

In a recent post to an EX rocket group I belong to,
Randall J. Ejma of Always Ready Rocketry,
www.alwaysreadyrocketry.com made the following
announcements; [somewhat edited.]

Due to amazing demand and positive feedback, ARR has
drastically reduced pricing for Blue Tube! These are
NOT sale prices; these are the new regular pricing!
Check out your nearest dealer first at;
www.whatstyourrocketmadeof.com
Or order directly from ARR. New pricing takes effect
immediately and is almost 40% less expensive!

Also, ARR has recently released;
Six Electronics bays from 38mm to 6 inch, and four new kits
making 5 total.

The moment Randall announced Blue Tube on our group, in
March, I had to post back about whether it would make a
good liner for EX motor making.

The following is the recent post of his test results.
[again, some editing]

Hey guys,
I know a number of you have been asking.
We've gotten some 54mm and 75mm casting tube and liner
sets w/Blue Tube as the liner. We've static fired 2 motors
and flown 1 so far and it has proven to be a far less expensive
alternative to convolute phenolic, it just needs to be thicker
for it to workin a motor design where spiral wound phenolic
isn't good enough.  It just gets too toasty for it.
As a replacement for spiral wound, it seems to work so far,
but when you throw lots of Al and unusually high pressures,
the chance of burn through is fairly high. It would probably
need to be thicker.
I fired a K-550W clone in a Loki case and I could stand on the
liner after firing and it held me up.  Worked perfectly.
But, another test w/a high isp, high pressure, high temp
design that normally only workes w/a convolute liner,
burned through Blue Tube.
Randall

That's a pretty good description of Blue Tube's limits inside a
motor. It appears to fall between the capabilites of spiral
phenolic and convolute phenolic.
I'm curious enough to try some in a couple of my motors
when the sizes I need become available.

One final update; Balsa Machining Service has joined the growing
list of Blue Tube dealers, and is offering laser cut tube slotting of
Blue Tube.

A Really Big Pair

I finished making these 2 nozzles for longtime rocket buddy, Don C., a few days ago.  They aren't the biggest nozzles I've worked on, I once helped design and produce a 2 piece nozzle that was 8" dia., but these are the biggest that I've CAD designed myself and turned on my own lathe.
Eureka! ZZakk's Lab has produced monsters!  Bwa-ha-ha-haaa!!!  

Ahem, in the lower pic they're posed with one of the Cesaroni Pro98 motor cases that they were made for, and the fabulously expensive spanner tool that Cesaroni now sells for installing the retainer rings.  Actually, just about anything you need or want for 4" rocket motors is fabulously expensive. The Cesaroni cases are designed and licensed [fabu dinero, I'm sure] to operate with Aerotech reloads as well as Cesaroni reloads.  This is a good thing since it increases the versatility of the hardware.  My friend however, is currently making his own Moonburn reloads for the cases, and using RCS/Aerotech supplies in the process.  The RCS 98mm nozzles are $44 each for a single use, and in the case of the 5/8" throat on the right, would still need to be custom bored anyway.  My graphite nozzles are completely reusable, and if need be, I can remachine the throats later if they get too crusty, chipped, or a larger throat is desired.  Some internal fuel volume is sacrificed but I added a much better expansion ratio, between 5:1 & 6:1 instead of only 2:1.

Last year, I looked long and hard at the costs of larger motors.  I decided to go with 3" hardware since it costs less than 4" every step of the way, despite the longer length needed for the same power.  Plus, being a hybrid flyer, a 3" combustion chamber is plenty big enough, AND, I'm already used to building rockets that take relatively long motors.

More recently, I rescued a belled 3" case from another friends recycling pile. Thanks RK!  
I trimmed the ends off, but still need to cut new snap-ring grooves.  It's kinda short, but I'm on my way!  When I get around to buying new 3" motor cases, I'm gonna give the
Cesaroni hardware another good look.