Success of the Campitch 2, an update

The Alamo Rocketeers had a night launch and weenie roast on Nov 20. The first time I've done any night flying in years and years. We started early enough to do some day flying too.
Right after sundown I flew the Campitch 2 without any visual augmentation. I used an entirely antique Aerotech E10-4wl moonburner that I had been hanging onto for years. The flight was fantastic, a complete success and a worthy use for that old motor. It was a blustery evening but the CP-2 maintained good stability, achieved a respectable altitude and was in full autorotation mode about 1/2 way down, landing less than 100 feet downwind.

After the last time I flew the CP-2 I obtained a new piece of 3/16" graphite tubing, cutting a new flybar 3" longer and then added internal wire tipweights to increase the weight from 11g to about 20g, nearly doubled.

Snaking the thermalite ignitor fuse into the offset port on that E10 was definitely cause for reminiscence. Ahhh... the moonburners that I have known. I initiated the thermalite with a
Quest Q2 ignitor. If I'd remembered them Id've used a flashbulb initiator to wow the crowd.

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 2

Pics by: KeithAlanK

This is the new improved Campitch 2.
It has the same features as the defunk Campitch 1 but is larger and beefier. Most notable is that the wing is much larger, by nearly 50%. The span is 2" longer, but the wing is made from
1/4" x 4" Sig airfoil stock instead of 3/16" x 3" stock. The thicker wing allows for a thicker 3/16" carbon pivot rod instead of the 1/8" carbon, then steel pivot rod on the CP-1. The hub assembly is about 1/2" longer on the motor side.

The CP-2 is already leading a better, or at least charmed, life than the CP-1 did. It has made three flights so far with nothing worse than some burn through charring [routine] and a ding on the wing tip.

The first flight back in August had us rolling on the ground, and we weren't even on fire! I launched the CP-2 on an Estes D12-3, it took off from a 2x4 pad low on the ground and ascended to no more than 3ft as it travelled 5-6ft upwind, then curved left going just over a modroc launch rack passing through a gap in the launch rods with scant centimeters to spare, then it drifted back downwind to land right next to it's takeoff point. It looked a lot like an olympic highjumper in action.

Todd, one of my flying buddies said he'd buy me lunch if I would fly it again. I didn't have any more suitable motors for it, so I told him I would if he could donate an Estes E9. For various reasons, I had yet to use any E9's before, so this one was my 1st. Well that turned in a perfect flight, 60-70ft up, transitioning to full autorotation mode about 1/2 way down and landing about 100ft downwind.

September launch dates were all rained out, so I had to wait till October for flight #3. Since the CP-2 flew so well on an E9 I figured it could handle one of my long sugar moonburners. These are sized the same as the E9 though heavier start to finish and has a higher sustain burn and longer duration. Well this spinny thang tookoff and immediately tilted about 45 degrees downwind for about 100ft then curved back and up in a boomerang turn till it was knife edged, pointing into the wind, at which point it ran out of sugar and dropped straight into the ground. Amazingly, the only damage was a little mushing of the wingtip, easily fixed by supergluing my fingertips to it.
The only other time I ever saw a monocopter with quite that flight profile was when I actually launched one with no flybar installed at all. Obviously a flybar with more authority is needed.
Not too surprising really, since the flybar was the same one the smaller CP-1 used.

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.

Campitch 1 Monocopter Pt1

This is the Campitch 1.  The 1st of 2 recently finished
monocopters. Both monos employ quite different wing
control mechanisms, but I decided to build both at once
because most of the construction is routine enough to be
a bit boring and I always mix too much epoxy  anyway.  

The Campitch 1 uses a system similar to that of the
Rotary Space Ship that I posted about back in March of
this year. When the vehicle begins to rotate, centrifigal
force causes the wing to slide outward on its' pivot rod,
as it does so, a pin on top of the wing root follows a
cam track causing the wing to rotate from down pitch to
up so that it can ascend.  Once the motor burns out, the
mono will slow it's spin until a spring can retract the
wing, returning it to down pitch so that it can autorotate
for a gentle landing.   No stopping, no falling.  

Now, I've done away with the burn string that the
Mousetrap requires.  After I work the bugs out on D12's,
I'll be able to fly it on my own small moonburn sugar motors.

Uncle Walt Believed

Early today I read that NASA released some early photos
from the LRO, Lunar Reconnaissance Orbiter, showing
most of the Apollo landing sites on the moon.
Curmudgeons Corner, the blog that clued me in,  said that
the conspiracy nuts are now invited to apologize and then
shut up.   My first thought was that this is a NASA
spacecraft and therefore not independant coroboration.  

Bah!
I didn't bother leaving a comment, let alone feeling the
need to compose this post.

On the evening news I found out that Walter Cronkite
passed away today. I grew up watching Uncle Walt on
the news.  He was a great great man, and a first rate
journalist.  He was also a staunch supporter of the space
program, but no wide eyed fool.  So, here's my answer to
all the lunar landing hoax theorists;  

Walter Cronkite believed!

Goodbye Walt, you'll be missed.  11/4/16-7/17/09

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.

LDRS-6 & the Black Brant II

This is a pic taken of me at LDRS-6 in August of 1987.
Hartsell Colorado. The launch site was 8800ft ASL.
Jogging is NOT recommended.
We saw a number of rockets, that were said to be
perfectly stable at home fields, go unstable in flight
due to the thinner air.
Of course, this being LDRS, a lot of rockets had bigger
motors in them than ever flown at home. Please take
no notice at this time of how the motor protrudes
from my rocket.

I'm holding my FSI Black Brant II. A fine kit for it's day
and an excellent flier. I did a great job on it, and it
drew a lot of compliments, though I left off the myriad
screw head details. Each fin was composed of 7 pieces;
a 1/32"ply core with airframe tongues, a tapered
hardwood spar on each side, for the airfoil highpoint,
then 4 pieces of sheet balsa to complete the structure.
This was a lot of work, but it made it a lot easier to
sand an accurate airfoil, and made for a much sturdier
fin and mounting than the stock 1/4" balsa.

In 1987; Reloads didn't exist, Glassing was rare, and I
know of only one altimeter flown at the entire launch.

The too long motor is an Aerotek G25. One of the great
moonburners of the past. 4.7 second burn! I had signed-up
to have Chuck Rogers do altitude tracking but the LCO
launched me early by mistake. Too bad, 'cause it was
really up there!
I finally lost the Black Brant years later in a
ridiculously small patch of woods a very short distance
from my house. I looked many times, it just vanished.

I was 27 when this pic was taken, not a grey hair to be
seen. The antique safety glasses I'm wearing were given
to me by a friend. I had the stock green torch lenses
replaced with blue-block lenses which are great for
rocket tracking. Any paint with red or orange pigment
stands out big-time.  Those glasses were so ME, long, long
before steam got riveted to punk.
One Saturday morning, I dragged my butt to work after a
vile night of debauchery. I turned to a co-worker, tapped
on the glasses and said; "I'm wearing these glasses for
your safety, not mine."

Rotary Space Ship, Totally Cool Toy

This is a monocopter. Monocopters are flyng devices or helicopter rotor heads that have only one wing or blade and are typically counterbalanced by one or more sources of thrust, like a propeller drive, jet, or rocket motor.

I found this pic on Dick's Rocket Dungeon a few months ago..
http://rocketdungeon.blogspot.com/
Dick Stafford and I searched the web extensively in hopes of finding a better pic and/or more info. It's called; Rotary Space Ship and was made by Brown Mfg. Co. of Clinton MO. It was probably produced in the 1950's or very early  '60's. It's certainly not the first monocopter, since Pappin did build his monster, but it may well be the 1st rocket powered monocopter.  
My research turned up a few pertinent facts. #1; Brown Mfg had  a sister company called Zenith Fireworks. Brown Mfg is long gone, but Zenith Specialties is still in business today. #2; Orville Carlisle [the inventor of Model Rocketry] contracted Brown/Zenith to make the first mass-produced model rocket motors for a while.  When Dick and I first discussed it, he thought the RSS might be powered by fireworks rockets with the fins or sticks removed.  That may well be the case depending on time of manufacture, but I rather think that it was powered by either Carlisle's Roc-a-Chute model rocket motors, or a custom motor made for the job.  Given the relatively high weight, and a crap airfoil, the
RSS probably needed a fair bit of power.  This would be a perfect use for a classic Moonburner rocket motor.

Except for the wooden wheels the RSS appears to be all metal.  I think the wing really is made out of a BBQ spatula. Sure looks it.  Obviously it was meant to rise off the ground, and in a spacious parking lot, it will make a nice landing too.  It has a centrifugal wing
pitch mechanism with spring return. As rpm increases during takeoff, centrifugal force makes the wing slide outward, causing it to rotate into up pitch for ascent. Later, as the rpm slows, the spring retracts the wing, causing it to rotate back into descent pitch for a smooth transition to autorotation for a gentle landing.

Judging from the size of the box, I'll betcha the axle mount is meant to pivot so the assembled toy fits back in the box for storage and safe transport. It may not be a kit at all, considering the construction methods.

One last thing; if this were produced today, the CPSC would have a bigger cow than the NAR.  Lack of takeoff guidance is one thing, metal parts are another, but if that wing were to hit somebody...
 

Sugar Motor Data II

Today, we're looking at the data for the second
motor tested last month. This one is 538-M2.
The M in the designation stands for Moonburn.
In the lower illustration, you can see that the 
motors core is offset to one side, instead of in
the center.  As the motor burns, consuming
the propellant, the remaining propellant looks
like a waning crescent moon.
I about fell in love with moonburners back in the
'80's, when there were a number of them available
to choose from. Later they all but disappeared
from the market. This was a major prod for me to
start making my own motors.  BTW; Publishing
these motor graphs was the final prod to start this
blog. By nature, a classic moonburner is typically
slow to reach maximum thrust, so I wasn't going to
fly this motor design until I saw a thrust graph.
I intend to test a couple more to be sure, but in my
motor, the thrust does rise quickly, so it looks like
I have a great sport motor here. I'll fly them as such
soon, but I was originally trying to make a clustered
airstart motor. I still want a somewhat slower thrust
ramp up, to avoid disturbing the rocket's trajectory 
if the motors in the cluster lights unevenly.