Monday, August 27, 2012

DEFCON 1


DEFCON 1 stands for DEFense CONdition 1, which means highest alert level for military defense.  The fantasy story behind this model is that it is supposed to be a high-altitude radiation detection rocket.  The US is supposed to send a bunch of these up to confirm detonation of nuclear bombs at the start of the next “big one”.

This kit is produced by Quasar One.  I believe they are no longer making kits.  I chose this rocket because the decoration looked great, I love the color, and that is all created simply from large decals.  Also I was looking to get into more powerful rockets; it has a slightly larger and more powerful motor mount.  This makes it my first true “mid-power” rocket, taking 18mm C’s, 24mm D’s and E’s and even F’s if I dare.  The fins look like it can take some abuse, and it is very tall (i.e. impressive).

As it happened, the company went out of business and I unwittingly bought leftover stock which when shipped to me the tube was crushed. The replacement tube was also crushed in shipping, and there were no more.  I managed to splice together the two pieces to restore the original length and make a large, 10-inch long payload bay, thinking I might use this as a camera booster.  Either way, it looks great and I expect
it to fly well.





I took this picture to better show you what the baffle is like. The baffle is used to cool the ejection gasses coming from the hot motor to blow out the parachute with out melting it. Already glued into the baffle's tube coupler is the lowest baffle as seen from the bottom (engine side). Above that will be the baffle to the left, shown right-side-up. Ejection gas that makes it past this stage can't move towards the center until it passes the small 13mm tube glued to the top of the second baffle. Positioned just above that 13mm tube will be the top baffle where gas ejects from the center hole. (The small hole is to mount a Kevlar shock cord mount.)  This whole baffle assembly will be positioned as far to the top of the body tube as possible, while allowing room for the parachute, shock cord, bulkhead and a little bit more. There are two reasons to have it as far up as possible. 1) Improve stability by keeping as much weight towards the nose of the rocket, and 2) Allow plenty of space for the ejection gas to cool and prevent over-pressurization of the body tube in a too-small lower section. Worst-case, a extra strong ejection charge could cause the lower chamber to burst wide open. If that were the case the parachute would not eject but that really doesn't matter at that point because all you'd get back is a pile of cardboard and balsa scrap.


You can see here the unusual nose cone provided with the kit. It is supposed to remain hollow, and the screw-eye is towards the side of the shoulder. This makes it easy to add nose weight if necessary, and I suppose makes it a bit cheaper to manufacture.



The problem with this unique design is that the part of the plastic that takes the screw creates a nasty dip in the outside of the cone. It had to be filled with plastic puty and sanded back to shape. I suppose the mold designer didn't expect that to happen, and I imagine with the cost of the plastic mold in the range of real estate, it was way too expensive to remake or modify the mold.

The sunk-in area of the molded nosecone was filled with plastic putty and sanded smooth. The green filler shows where this molded-in depression was.




The hollow nosecone is actually a disadvantage to me, since I was intending the nose cone to be the forward limit of the payload guts. Worried that the payload will shift forward into the nosecone, I had to glue in a stop to the end of the shoulder made from a strip of balsa.



The finished ejection baffle, seen from the point of view of the motor. You can see the Kevlar shock cord attachment, connected to the other (top) side of the baffle. This has a bowline type knot on the end of it. It's a simple and secure type of knot that won't work lose under tension and it won't pull tight into a smaller loop, but keeps the loop for tying a rubber shock cord. The knot is secured with a dab or two of glue also. It's length is sized to be just short of the body tube so it will not create zipper damage on a early or late ejection.
The silver color is a special high-temperature paint, which should be good to 1000 degrees F. A quick, thick shot of this will protect the basswood and cardboard from the hot particles of the ejection.




The basla bulkhead which I will conviently use to connect two good pieces of the shipping-damaged body tube, and will give me a seperate
payload section for electronics and a camera. After loosing a similar payload when the screw-eye to balsa joint failed, I made sure to glue
it well and added a length of Kevlar glued to the bulkhead. The Kevlar is supposed to be a backup glue-joint if the screw-eye works loose. I
could use a heavy nut and bolt, but this is much lighter.



The motor tube and mount supplied by Quasar. 24mm inside diameter and 95mm long (D-E size). These are very good components. Notice the
foil-lined motor tube, to help it withstand the heat of those long-burning motors.

  Building the DEFCON is going well.  I secured the baffle about 8 inches deep inside the lower body tube (remember I had to cut it into two pieces because of the shipping damage).  On other projects I had trouble gluing baffles so far into a tube.  If I spill any glue ahead of the intended spot, the baffle is likely to stick in place before I get it pushed deep enough into position, and I'm left with not enough room for the parachute.  So for this I fashioned a small "cup" from folded aluminum foil and taped it to a long stick. I marked the stick 8" from the cup end, filled the cup with glue and inserted it to the 8-inch mark. When the glue was where it was supposed to be, I turned the cup over and let the glue run out into the tube 8 inches down from the end. (of course the tube was lying flat horizontal).  When happy with the amount of glue, I waited for the glue to stop dripping, turned the cup over and removed it quickly before any glue dripped elsewhere in the tube.

I then stuck the ejection baffle assembly with the Kevlar mount in the tube and using a pre-marked broom-handle sized dowel, quickly pushed it all the way down into place.  I turned the tube upside-down so the glue wouldn't run to the motor mount end and let the glue cure for a day.  All was well.  Then I glued in the motor mount and added fillets according to the directions.  Note that the centering rings were high quality, they fit tight but well on both tubes.  I then hardened both edges of the main body tube with a line of CA glue on the inside which soaks into the paper.

I marked the tube for the three fins. The instructions say to use the fin marking guide - but my kit didn't have one!**  I looked through each page of the instructions to see if it was to be cut out of the instructions and there wasn't any one in there either!  I had to do it the old fashioned way, taking a strip of paper wrapped around the tube, then layed it out flat and measured the circumference, divided it into thirds and marked it.  I re-wrapped it to the body tube and transferred the markings.  I made sure to place one fin close to the motor
clip, so the launch lug (and therefore the metal launch rod) and metal clip are all on one side - away from the ignitor wires.

**Sorry: I place all the parts from the rocket kit bag into a cardboard box during construction.  I found the fin marking guide hiding between the decal sheets.  So that's my fault, not Quazar One's.
I put the fins into my home-made fin alignment jig and glued them on, 1 fin at a time, giving each glue joint a full day to cure before handling the rocket.  Fillets will come later.  The cool thing about my home-made jig is that the body tube is held in by thick elastic bungees (shock cord for high-power rockets). This allows me to fit the fins perfectly in the jig with the body tube, then "stretch" the body tube down a bit and apply the glue.  When happy with the glue I release the body tube slowly and it presses into the fin exactly where it is supposed to be.  That jig is awesome!

I prepared the fins according to the instructions, being careful not to sand too much and make the fin outline smaller, the decals for the fins are designed to cover the entire fin area, so if too much leading or trailing edge is sanded down the decal will not fit.  I did one mod to the fins though, I paper covered both sides of the balsa, tacked down with a generous layer of scotch photo mount adhesive.  This is much - much - easier than sanding sealer to give the fins a smooth, grain free finish.  Also much better on the lungs.

I realize on this particular model that decals will be covering any balsa grain texture, but this way I'll have a smooth surface for the decals and I believe the paper covering adds strength to the fins also.  If you use plenty of adhesive on the paper, you can then sand the edges of the fins without fear of the paper peeling up and create a smooth, invisible seam between the paper and balsa.  I might also soak the edges of the fins with CA glue to harden them up against dings.

All I need to do now is glue on the launch lugs, fillet the fins and lugs, and this puppy is ready for a good priming!  With the full-body wrap decals, I shouldn't have to worry about tube spirals.


I have progressed pretty far with the DEFCON 1. I soaked in a little CA glue to the ends of the body tube and payload tube to harden them up a bit.  Just a small line of glue about 1/4" from the ends of the tube keeps them from getting worn and raggedy after repeated handling.  The CA glue makes the insides a bit rough and makes a tight fit for the nosecone or bulkhead, so I sand the insides down to a smooth feel.
I assembled the parachute. I was VERY pleased with the materials supplied.  First the plastic material is thicker and sturdier than the usual "Estes-grade" stuff.  Sure it's a bit heaver, but since this is a D-E powered rocket it should be easy to lift a few more grams.

The shroud line appeared very strong, and there was plenty of it.  Generally, parachute shroud length is suggested to be a minimum length equal to the diameter of the parachute.  I've never had a kit that supplied more than the minimum, until this Quazar One kit.  With the few parachutes I built myself I used shroud lines 2X the diameter of the 'chute, and they seem to work well and wobble less.  The supplied shroud lines for this DEFCON 1 kit was enough to make 2X length shroud lines.

Additionally, they included a nice heavy duty swivel to attach the parachute.  After looping the shroud lines through this swivel, I dabbed glue to the confluence point to keep the shroud lines in place there. I've had other shroud lines slip through these points and cause the parachute to have one long and one short line, leaving the whole canopy lopsided and falling too fast.  The supplied shock cord, which is 1/4" thick elastic and quite long was another fine quality suprise.

The other end of the swivel is attached to a mid-point on the shock cord.  While they instructed me to attach it to the body Estes-style, I instead attached it to the Kevlar loop I installed.  I'd have to give Quazar One an A for the parachute material (A+ would have been if they used thin-mil nylon or silk, which doesn't freeze solid in cold weather).

The body and nosecone have been primed and sanded. The body tubes painted gloss white.  I painted the inside end of the body around the motor tube bright red using a brush. After the paint has dried for several days, I started to apply the decals.  I started with the fins and they fit nearly perfectly, but the tips of the decals did seem to stretch a bit when wet, making the fit just less than perfect.  The much larger body tube decals was a challenge, getting the whole piece on straight and flat with no bubbles took a while.  I had assumed the the darker aqua color would hide a few drops of red paint I left on the white, but those mistakes showed right through the decals.  I also hoped the body tube spirals would be hidden by the decals, but after the decals dried the spirals show right through.
 The three large decal sheets that wrap around the body are a bit oversized, so they overlap about 3/16" on one side, and it looks a bit ugly and leaves a slightly raised seam.  If I had known that, I would have trimmed them a little tighter.  Still, they do look pretty good from the other side, and it was a lot less work than masking, painting multiple colors and applying a dozen or so smaller decals.  One large decal sheet has a cutout for the launch lug, so I started with that one to get it to align up right, even if it meant I'd end up with a gap where the white paint shows on the body tube.

These decal sheets appear to be much duller and flat looking then they did before being applied, so I hope to add a bunch of coats of gloss clearcoat so it looks to have the same finish as the bare white gloss paint.  It also can't hurt to protect the decals more.
I had trouble painting the nosecone to a bright silver finish. The first attempt was a bit rough, so I sanded a lot of the finish off.  The second set of coats came out too thick and started to run, so I sanded that finish down again. The third set of silver paint coatings came out just right.


While the decals dry out for a few days, I am working on the payload section.  I am building a small balsa wood structure to hold an Altimeter 2 and optionally a small video camera and/or a sonic locator.  Since this payload section is a bit oversized, I don't want to fill the whole insides with heavy padding.  The light, open balsa structure is lighter and should keep the electronics from rattling around in there during flight.

Since the payload bay is quite large in volume, the normal 1/16" static vent holes will be too small to vent such a large volume of air. I have the choice of either making the holes larger, or making more of them. I haven't decided, but I am leaning towards making more holes, perhaps 6 equally spaced around the tube, and probably making a second or third set of six vent holes further up & down the tube. (If I put about 18 holes all in the same line, I would essentially be perforating the tube and inviting damage by creating a very weak point in the tube.)

That is all for now, I don't expect it to be ready for this weekend's flying, so it's maiden flight is scheduled for Labor Day weekend 2012...weather permitting.



OK! The clearcoating is finished and dried, now the finish is glossy. I gave it five coats of clear. I have found that one or two coats just doesn't protect the decals very much, so I have been adding much more clearcoat.
I made sure the static vent holes were clear and assembled the full rocket and put it on the scale.

The total assembly weighs in at 137.3 grams. If I subtract the added payload filler and bulkhead I added (11.65g) and the ejection baffle (7.7g), the rocket is 125.65 grams, or 4.432 oz. The kit card spec'd the rocket at 4.4 oz, so this is just  0.032 ounces over that. That was probably an extra half-second of glue squirt somewhere.
My best predictions for this model based on other altimeter readings is that I should expect a D12 motor to give me 800-900 feet and about 180 mph.  I would rather first-test it with a C11 motor, which I predict will give me 350-450 feet and about 100 mph. The first test flight is scheduled for Labor Day weekend 2012, but I won't fly this new model if there is any significant gusts. If not then, I may have to wait for November or December.
Overall, I would have to say that this was a very easy kit to build.  It was very easy to finish too, yet I have a rocket with some really good visual appeal, thanks to the decal sheets and the overall length. Now if she flies well, I will have to be bummed that Quazar One is no longer making kits. My gut feel is that this will become one of my new favorites to fly.



SPECIFICATIONS

Serial number: 26
Number of Stages: 1
Stock Length: 39.5"
Payload Length: 10.56"
Tip-to-tail Length with Payload: 39.5"
Diameter: 1.325"
Fin Circular Span: 6.33"
Payload Internal Length: 9.06"
Payload Internal Diameter: 1.28"
Payload Volume: 11.66 cubic inches
Stock Mass: 125.65 grams
Payload bulkhead and padding mass: 11.65 grams
18mm-24mm motor adaptor mass: 5.55 grams
Payload ready mass: 137.3 grams
Liftoff Weight Range: 163-200.9 grams
Motor Diameter: 24mm, 18mm with adaptor
Motor Length: 95mm, 70mm with adaptor
Recovery: 18" plastic parachute
Recovery Protection: Ejection Baffle
Shock Cord Mount: Kevlar
Fins: 3, paper-covered balsa
Construction Started: June 19, 2012
Construction Finished: August 22, 2012


FLIGHT LOG


2012, Sept 1: Indiantown Gap, 10-7mph winds



C11-5: This was the first ever test flight of the new DEFCON 1. Several remarked that this was a good looking rocket, and I hoped it would stay that way. The winds were dying down a bit, and I felt that the higher impulse, relatively light weight and long length would keep this rocket from being affected by the winds much.

The motor ignited and she lifted off the rod and burned for 7/10 seconds, flying fast and straight, reaching a respectable speed of 81 mph. The readings for acceleration indicated how little the winds affected the flight, with the peak Gs at 10.9 and the average acceleration at 5.3 Gs.  These numbers were similar to a Big Bertha of about the same weight. The DEFCON then bled off the 81 mph speed in the next 3.8 seconds, reaching an apogee of 275 feet above.

 



Ejection fired a bit early at 4.2 seconds, but it was near perfect for this flight, as the DEFCON only dropped 2 feet in the last 4/10 seconds before the parachute popped at 273 feet.  The color-coordinated parachute filled with air and the rocket came down at 8 mph, landing about 120 feet downwind. Total flight time was 27 seconds. A perfect first flight.  The altitude was lower than the kit card or the apogee website estimated, claiming 366 and 411 feet respectively.



 


D12-5: After flying a different rocket I decided I wanted to send this up again for its second test flight, this time with the more powerful D12. The winds continued to die down more, so I was sure this wouldn’t get lost.  Though I thought it would fly well on the way up, I didn’t want this new rocket to get lost in a drift.  The manufacturer claimed 980 feet for this motor.




The D12 burned for 1.9 seconds, its peak thrust giving the rocket 12.4 Gs of acceleration.  For the entire burn, the average acceleration was 3.1 Gs, giving the rocket enough energy to reach 131 mph on its fast, straight climb.  It then coasted for 5.6 seconds but still did not slow enough before the ejection fired slightly (2/10 sec) early as it reached 668 feet.  With the rocket opened it slowed in the next 8/10 seconds to an apogee of exactly 700 feet, having climbed an additional 32 feet.







There apparently was not enough ejection pressure because the parachute, though not stuck tight, did not leave the tube.  First the empty engine casing landed on the ground, then the rest of the rocket fell to earth at 20 mph, but it landed in the grass safely, about 80 feet upwind, with no dings or cracks.  The motor mount and engine clip appeared in fine condition and was not damaged in any way.




This same problem was happening with my Bandit II, which kept rejecting D12 casings and not deploying the parachutes all the time. Co-incidentally it also had an ejection baffle installed.  Puzzling since this rocket was built with at least a foot of empty tube space before the baffle.  I believed that was plenty of volume to prevent over-pressurization.




My current thinking is that I have learned that these baffles are not so reliable for higher power motors with their stronger ejection pressures, and I should cut/drill out the DEFCON’s baffle and use Nomex before using higher power motors.  My love affair with baffles has ended, but my love affair with the DEFCON 1 has just started – She looks great and flies well!



The DEFCON 1 has been repaired and is again ready for flight.  I drilled out the baffle, and installed a new shock cord (the old one was damaged while drilling).  This time I included a 6"x6" fireproof Nomex cloth attached to the shock cord, so I will not need to use wadding and I shouldn't have the problems of motor ejection with a D12 motor or hopefully even more powerful motors.


2013, January 13: Penn Manor, 5 mph wind, drizzly and damp


C11-5:  As this is still an almost new rocket, I was unsure how high it would go today. The winds were light but the weather was quite foggy, and I didn’t want to lose this in the low visibility. I expected it to be a low flight, but I was not sure.


When the motor lit, she took off well and straight, accelerating at 10.6 Gs, and averaging 5 Gs for the 6/10 second burn time.  This gave the rocket a meager velocity of 65 mph and she coasted for the next 3.3 seconds to an apogee of 200 feet exactly.  It then turned over and began to fall for the next 1.4 seconds.  It was good that the ejection was short by 3/10 seconds, and it fired at 165 feet.








The parachute was wrapped in Nomex and was a little tight, so it only came part way out of the body tube and the rocket fell fast at 22 mph.  It landed in the wet grass and was not damaged.  Flight time was only 9.8 seconds.  In spite of the low 200-foot flight, it drifted about 300 feet upwind.
The previous flight also had a deployment problem, that was due to the baffle.  This time, the baffle was drilled-out, but the Nomex used to protect the ‘chute made it a tight fit in the rocket.



Here we see how the parachute almost made it out of the tube. Just didn't make it all the way, possibly because some of the baffle is still installed.










C11-5:  I made a second flight with this rocket, but this time I removed the Nomex blanket and used plain-old dog barf for wadding.

The rocket took off well, flew straight up, peaking the acceleration at 10.2 Gs and averaging 5 Gs for the 6/10 second burn – all very normal.  It didn’t fly so fast, only reaching 69 mph and coasted for 3.4 seconds to an apogee of 226 feet.  This was enough to cause the rocket to become nearly invisible in the fog.


Again the delay charge was a bit short at only 4.3 seconds, which helped this particular flight.  The rocket only descended 16 feet in 9/10 seconds to reach 210 feet above ground when the parachute deployed.
This time the ‘chute opened cleanly.  The wind seemed to catch it and it started drifting rapidly downwind, causing me some alarm, but it only lasted a second or two before falling more directly.

The rocket descended at 10 mph.  The flight was over in 18.9 seconds, landing downwind in the grass about 250 feet away.


2013, August 31: Fort Indiantown Gap, 5 mph wind, 86 degrees

D12-7: I have only flown this model once with a D12 before. This time I will use the 7 second delay since it appeared to need another second or two to maximize the apogee in its last flight. To prevent its possible loss, I swapped out the stock 18 inch 'chute for a bright pink 14 inch 'chute.

As the mighty D12 started burning, it accelerated off the pad much quicker than I anticipated, peaking at 10.8 Gs. The motor burned quickly and for only 1.7 seconds, accelerating at 3.2 Gs on average and reaching a top speed of 118 mph. I lost sight of it as it flew straight up in the light winds.




It coasted during the long 7.5 second delay, then fired the ejection while still travelling upwards.  As the parachute deployed in the last 2/10 seconds, it continued up from 531 feet to a 649 feet apogee. (That would be > 400 mph? There seems to be a slight altimeter accuracy error in these numbers - but that is all I have to go on.)

Oddly, even though it had a much longer delay then last time (7.5 vs. 4.8 seconds), it didn't reach as high as before. This seems to happen to me a lot, where a longer delay more often than not produces a lower altitude. I can't explain it. I expected much more than 700 feet from this flight.


A fully deployed parachute then brought the rocket back to earth at 12 mph, landing safely about 300 feet away and undamaged. 


2015, July 5: Cross Keys Field NJ, 5 mph winds, 88 degrees F, 50% RH

D12-7: Having spent way too much time looking for my Bandit in the weeds, I pulled out
one of the tallest rockets I brought today, the DEFCON 1.  Standing a mere 1 millimeter shy
of a full meter, it should be easy to find “out there”.  I would go with another D-
flight, lifting it high but not too high.  I predicted an apogee of 750 feet, even though the DEFCON 1 hasn’t reached that altitude on the D before.  Hard to say why, since I wrote
up the flight schedule a year ago. I suppose I was being optimistic.



The DEFCON 1 looked pretty on the pad, but not for long.  With the burning propellant
pushing her she left in a hurry, generating 12.1 times the force of gravity.  The burn
continued for 1.8 seconds at a reduced rate, averaging 3.2 Gs in that time.  This pushed
the DEFCON 1 to a top speed of 121 mph, better than any previous flight, even with a
similar D12-7.

Shortly after ejection, we saw the DEFCON 1 with the parachute out and free.

The ‘def coasted for the next 5.2 seconds and bled off speed, reaching an apogee of 656
feet – respectable but not any record here.  The motor had a generously long delay of 6.6
seconds, giving the ‘def time to turn over and for the next 1.4 seconds start heading
downwards.  She dropped 31 feet before the ejection fired, so at 625 feet I could see the
matching teal parachute wrapping itself up in the shock cord.  I expected it to come down hard.

A short time later, the parachute shrouds wrapped themselves around the shock cord.
The DEFCON 1 appeared to be a goner.

Fortunately, this flight had what I call a “poor man’s dual delay”, so while traveling
rapidly downwards, the wind was enough to wrestle the parachute from the death-grip of
the shock cord, and the ‘chute presented itself for display.  I could see that it was not
a perfect canopy, as one shroud or two was folded in on itself.  Overall the descent
speed was clocked at 17, but she landed a lot slower than that. Flight time was 32.6
seconds, and it ended with a touchdown about 100 feet downwind.

 In a miraculous recovery, the parachute unwound itself and deployed!


 No, it wasn't a perfect canopy, but it did its job and brought the DEFCON 1 back safely.


C6-3: I love the look of this rocket, and in its six flights so far it has not endured
any flight damage, but it was meant to fly and that means taking risks.  This particular
test flight was to try out for the first time ever a C6 motor.  While the kit maker says
it can do that, it is a heavy rocket for the C6 and is beyond Estes’ conservative
recommendations for liftoff weight (by 36%).  But it is a fairly sleek design with long
length and narrow fins, so if any design short of a “minimum diameter” can do the job
than the DEFCON 1 is the next best thing.

I roughly predicted an apogee of 200 feet, and the risk here is that there is not much
time to get a good deploy from the parachute. (See the previous flight for why I think
that!)  I’ve had way too many of my rockets barely find 200 feet, and come crashing back
with either a long delay or a crumpled or stuck parachute, and I certainly didn’t want
this one to share the same fate.


This particular flight began with the ignition of propellant.  While the DEFCON 1 normally
enjoys a liftoff of over 10 Gs, this one only was able to peak at 5.5 Gs, and that was
plenty for a good liftoff.  The C6 burned for its usual satisfying 2 full seconds, and
the average acceleration of 1.2Gs made for a slow, sustained flight upwards and arcing
oddly away from the winds.  Top speed was only 54 mph.

The actual delay of this particular motor was short at only 2.1 seconds, and in this case
that served to help the flight.  The ejection charge fired at 212 feet, and 3/10 seconds
later it climbed another 9 feet to an apogee of 221 feet.


This time I was rewarded with a full, clean parachute, bringing the DEFCON 1 back at 9 mph.
 Total flight time was a fleeting 20.3 seconds. It landed like many flights today, only
100 feet from the launch pad.  I was pleased to find out I can fly this motor using the
somewhat more economical 18mm motors, and simultaneously not having to worry about the
model disappearing in the sky.  Instead I can devote all my worries to getting a good
‘chute.



C6-3: Temping fate, I flew a second low-power flight to make sure that the single
successful flight on a C6 wasn’t a fluke.  While it too was a successful flight, the
longer delay time and shorter duration flight reminded me that there was little margin
for error here.


This liftoff was almost one G shy of the previous flight, peaking at 4.9 Gs and averaging
the same 1.2 for the duration of the 2 second burn.  This flight reached a top speed of
only 52 mph, making it easy to track with a camera.


With a longer but still too short delay of 2.7 seconds, the DEFCON 1 was this time able to
reach an apogee of 202 feet and then fall another 4 feet in the last 3/10 seconds.



Ejection occurred at 198 feet and I again was relieved to see a good, fully opened 17”
teal parachute.  That parachute was supplied by the manufacturer and was selected to
match the large, full-body, wrapped decals that make this rocket look great.


Descending at 10 mph, this rocket landed at most about 75 feet from the launch pad,
likely the best spot-landing of the club on this day. The flight was over in a moment,
landing only 17.5 seconds after liftoff.  It was my 6th successful flight of the day, and
in fact made for 6/6 good flights for the year.  The sun has taken its toll on my
endurance, so after this flight I ended on a high note and called it a day.


2018, Nov 4: Penn Manor Field, 7 mph winds, 57 degrees F


C11-5:  I am making a redo flight to get a set of three flights with the C11 motor. One of those flights had the chute stuck in the tube, so I want some more clean data on this. I got it!


I know the C11 performs much better than the smaller C6, though not as good as a D12, but very useful in windy weather.  This day was not so windy, but too close to an active roadway for my tastes. It was an unusual south wind and the club accesses the new west field of Penn Manor from the north.  There was simply just too much of a chance for the rocket to strike the pavement and immediately be crushed by a car going 50 mph!


 
Yes, it looks like its launching right in front of the building, but really it was a good 600 or more feet away. That is the magic of a long lens, and then cropping for a small detail in a wider view.

So the modest C11 motor fired straight away, and pushed the DEFCON up with a relatively weak 9.3 Gs. It burned slower than usual, getting up to 73 mph with an average of 3.9 Gs for the burn.
This motor delayed for 4.5 seconds, and finally – a motor that delayed long enough to reach apogee! It first coasted for 3.4 seconds, reached apogee of 259 feet, and then descended 14 feet in the last 1.1 seconds before ejection.  At 245 feet the chute deployed, and the nice, 17”, matching aqua colored parachute spread out in the sunshine. It came back at 9 mph, and landed in the muddy plowed farm field to the northwest, about 100 feet downwind. Flight time was 22.1 seconds.


The Estes C11 motor is becoming a favorite of mine.

Compared to the other three C11 motor flights, this was a slow burner, slow accelerating motor. Otherwise it was an entirely nominal flight.  It looked pretty too!

.
.
.
May 25, 2019: Fort Indiantown Gap, PA, Winds 5-10mph, 70 degrees F


D12-7: Like the last C11 flight on an earlier day, I wanted to fly another re-do flight but this time using the D12, which like the C11 suffered a stuck chute early in the DEFCONs flying career.
.
.
This flight fired-up just fine, with a healthy 10.3 Gs of acceleration off the pad.  It was less than other D12 flights, but 10Gs is nothing to complain about.
.
The burn was the typical 1.8 seconds, but the average acceleration was a bit less at 3 Gs.  This pushed the rocket to a relatively slow 116 mph. This brought it to a relatively short 5 second coast to apogee of 619 feet, this number being lower than any of the other D12 flights also.
.
 .
With an actual delay time of a whopping 8.3 seconds, a full 3.3 seconds occurred before ejection.  At 454 feet the ejection occurred after dropping 165 feet – not straight down but in a long arc towards and past the sun where I lost sight of it.
.
.
In spite of the delay, I got a good parachute that allowed the descent at 8 mph.  Flight time was 44.7 seconds landing about 300 feet downwind.  Not only was this the longest apogee-to-ejection time, It must have grabbed a thermal since this was the DEFCON 1’s longest flight ever, and the slowest it ever came back to earth.  Since the goal was a good parachute, I’d say this flight was a raging success.
.
.
.
.
end.















No comments:

Post a Comment