Pequeño Diablo Update

     Pequeño Diablo, all painted and ready to go... I hope.

     After actually weighing the rocket and comparing the weight to that calculated in OpenRocket, I find that I may have underestimated a wee bit (42%!).  At just over 17 ounces, I am definitely pushing the limits of the motors that I have allowed for in this design.  I have run a few numbers and if need be I will bring a hack saw to the initial launch and remove as much as half of the 36" body tube to reduce weight.  I will attempt to launch on a central "E" motor (originally planned for a "D") and 3 "C" outer motors.

THREE AND A HALF FOOT DEVIL

      



     So I have embarked on a most ambitious project that I have dubbed Pequeño Diablo due to my planned red and black color scheme and the fact that when complete, the rocket will stand about 42" tall.  This is shorter than any devil that I have encountered, hence the "Pequeño" part.  The body tube was used to ship a poster and is 3 inches in diameter.

 I had some leftover Lexan from a car window replacement project (long story), and decided that it might make some nice fins.  Unfortunately these will not be remaining clear for this project, but I still have some more to use in the future where it may retain its crystal clear splendor. 

This rocket will sport a clustered engine design, able to accept 3 standard "C" engines surrounding a fat "C", standard "D" or "E" engine that will ignite simultaneously.

 The three outer engines are all angled toward a point roughly midway between the center of gravity (CG) and center of pressure (CP) as determined by plugging this rocket's information into a program called OpenRocket (like RocketSim).  This should prevent the rocket from running out of control if one or more engines fail to ignite.  

Since I believe in building rockets completely from scratch and almost exclusively with recycled materials, my nosecones are no exception.  I have developed a method that has proven successful over a dozen times now.  I carve the shape of the cone out of styrofoam (in this case two pieces had to be glued together to achieve the proper thickness), fill in any gaps with spackle, and then dip the whole thing in latex paint.  I let it dry, sand it a bit, and then dip it again.  After the desired smoothness is achieved, I then spray paint it with two coats of the final color.  The photo to the left is the nosecone after the 1st dip into paint.

More to come...

SHORT-LIVED SUCCESS

This 2-stage rocket was dubbed "Merca II"

     Unfortunately this rocket has ended up in the "lost" column but not without some degree of success.  It was a scratch-built, 2-stage rocket that was launched and recovered twice before I decided to make a video.  Below is a video of its final flight.  Despite launching on what seemed to be a windless day (at ground level) and cutting a hole in the parachute to make it descend more quickly, the wind (approx. 1000 ft up) carried it away and out of sight.  I should mention that there was also an original "Merca" that is still hanging up in a tree near my usual launch site.  At least I still have the booster stage from each rocket.

Booster stages from Merca (on right) and Merca II (left)

THE THIRD TIME WAS NOT THE CHARM

     So I had this idea to design a rather compact rocket that would launch on a fat C or standard D motor and achieve great height.  I believe that goal was met on 3 separate occasions, but unfortunately it was not with the same rocket as it was lost to the wind each time.  After I lost the first rocket (blue one above), I was determined to rebuild it (red rocket above) with a smaller parachute and look for a day with less wind.  At this second launch nearly the same exact thing happened.  Against my better judgement I rebuilt it a 3rd time with an even smaller parachute, perhaps 5" in diameter.  If I decide to rebuild it a 4th time I will either find a larger field (currently launching at a park with 6 regulation sized soccer fields arranged 2 deep by 3 wide with several hundred feet around the edges) or use a streamer for recovery.  The basic specs on this rocket have been 445 mm in overall length (about 17.5 inches), just under 2 ounces without motor, and with a body tube that is about 4 mm wider than the motor itself.  The center of pressure lies about 1 inch behind the center of gravity.  This was kind of a pain to achieve as the motor weighed almost as much as the rocket itself, so the nosecone was weighted with about 10 grams and the fins extend about an inch and a half beyond the end of the body tube.