Full Scale Harpoon Launch

Finally launched the Harpoon!

Flawless launch at Midwest Power 10. Only real issue is I lost the fairing that covered my Go Pro camera, but that was actually by design. I was really worried the fairing would collapse and I would loose any good video. I had read about making an Adruino motion sensing switch on a blog at the University of Illinois Engineering website (my Alma Mater) a few years back and thought it would make an interesting solution to my issue. I built a few prototypes, and eventually settled on a design that would blow the fairing off the rocket if a photosensor detected returning  laser radiation over a specific threshold. In the video below, you can see the fairing collapse right at 1:55), the Go Pro picking up the laser dot, then shortly afterward, the fairing is blown off the rocket by a small BP charge. Watching the landing from the ground,  I was also a bit worried at the end that the rocket would land on a local farmhouse. Luckily, it missed by a few hundred feet.

 

Full scale Harpoon Launch

 

The Harpoon has a very unique booster. I can reconfigure the rocket as necessary to fit any configuration of Motor’s I want within a 7.5” tube. Here’s a few photo’s to try and show how it works.

 

 

I’ll I have to do is make a new thrust plate, and centering rings to fly a completely different motor configuration. 100% of the motor thrust is transitioned to the bottom of the rocket, where it should be.

 

 

 

Next year The Harpoon will fly on  one large 150MM center motor, and several smaller air starts for effect. In the meantime, most of my winter building will be on a super-secret new project……

Another Saucer bites the dust

     Due to my schedule, and the fact my local rocket club doesn’t fly experimental motors, I only get to launch EX motors once a year, and Midwest Power in Princeton Illinois. EX motors are just that – typically a rocket propellant you whip up yourself in your garage, or basement. The big advantage of manufacturing your own motors is you can control a lot more variables. Want the flames to be red? add Strontium Nitrate. Need to speed up the burn rate of the propellant? Add Iron Oxide. Need an even thrust level through the entire burn? Try a Finocyl core geometry. You get the idea.

For the last few years, I’ve been trying to push the limit on making a slow-burning propellant. This is much more difficult than changing up the chemical composition because the longer the propellant burns, the more exposure the motor hardware, nozzle, and liner will have to the heat and pressure. Worse, the core geometries with the longest burn characteristics (endburner & moonburners) tend to keep the heat and pressure focused on a particular part of the case for an extended period of time. Once a formula is stable enough to flight test, I typically try them first in an oddroc saucer. They are very light – easy to lift of the pad, very stable – no fin alignment issues, and don’t fly very high – easy to recover just in case…..

In 2011, my longburn test ended in disaster. The propellant burn was so low, the rocket never got off the pad and eventually burned through the motor case, destroying the saucer, rocket motor, and the pad it was sitting on. All of this was caught on video at Midwest power 9 for your enjoyment

 

 

Needless to say, I spent a year with the nickname “firestarter” by everyone that witnessed this first attempt.

 

     A year

later,  with dozens of changes and testing of the propellant formula, I returned to Midwest power in the hopes of a successful launch.  The good news is the launch was successful – the saucer zoomed off the pad. The bad news is my nickname may now be permanent… After a successful flight, the rocket caught fire on decent and started a small  field fire. Once again, I was left with a destroyed rocket and motor. Of course, my daughter caught the whole flight on her iphone while I was clicking away on the still camera. At least I have another year for research!

 

Saucer and 75mm EX motor ready for launch

 

launch sequence

 

And the recovery……

 

This is all I got back, some burnt carbon fiber and a ruined rocket motor

The biggun’s

My wife and kids are off at the inlaws this weekend, so I thought it would be a good day to do some clean up. I pulled out all of my rocket’s larger than 7.5” diameter for a group shot

 

From left to right: 7.5" / 10ft Patriot : 10" / 9.5ft Maximum Thrust Thunderbird : 11.5" /16ft Harpoon : 9.25" / 18ft Iris : 7.5" / 13ft Nuclear Sledgehammer
For perspective, I put a 4 Grain Cesaroni Pro150 in front of the Iris.

LDRS 31

  Another LDRS 31 has come and gone. As usual, the hosting club put together a really nice event. The first day was much like my first day at LDRS 30: hot and dusty. You can always tell the weather by how my feet look at the end of the day. I was scheduled to launch the Pizza rocket for the Discovery channel first thing Saturday morning. Of course, I had a major last minute electronics failure. My WRC+ handheld unit decided it didn’t want to turn on. It’s a matched pair to the transceiver in the rocket, which meant I had to replace the electronics entirely. A quick trip to Wildman’s trailer, and I was back in business with a missileworks PET2+ timer. I quickly built a sled to install it into the nosecone of the pizza, and reprogrammed it to go off about a half a second after engine burnout. I didn’t have the right equipment to install a power switch, so I opted for the “twist and go” method – this may have been my downfall.

The good news is the Pizza had a great flight. I wasn’t too surprised at how well it flew, as I had at least 30 computer simulations before this launch. To build the simulations,  I had to make a lot of assumptions (guesses…) because the underlying software was really built for traditional rockets, and wasn’t totally confident in the math, or aerodynamics. Since the Discovery channel was filming me as I was watching the rocket, I wasn’t able to video, or photo the launch although – I did get some video of the setup, and the discovery channel film crew before the flight

Filming the sharp entertainment crew filming the oddrocs.

Luckily, several  other people were taking photo’s that day, and Chris Dondanville was nice enough to upload all of his photo’s to flickr. Below is a nice burst of shots of the Pizza rocket launch

 

 

 

 

 

 

     The bad news is the new electronics malfunctioned, and the parachute failed to come out. Either I programmed the electronics wrong (unlikely – I checked the programming after the launch), or the battery failed. I didn’t anticipate that the rocket would sit idle on the pad for about two hours in 100+ degree heat before the launch. I opted to use a radio shack private label brand nine volt battery. Probably a bad choice given the environment.

      The rocket is very light for it’s size (about 30 lbs), with a lot of drag, and it’s built like a tank. Crash landing had absolutely no effect on the rocket that I could find – it’s ready for the next flight. At the end of heat one, I was in the lead of the odd roc competition, primarily because every rocket before mine either cato’d, or disintegrated in flight. I can’t reveal whether or not I won

Odd-Roc’s

I fellow park flyer commented the other day that my blog doesn’t adequately  represent my rocket collection, and frankly, he’s right. My girls are enamored with finding things around the house and yard and asking “Dad, can you turn this into a rocket”. The answer is usually yes. About 80% of my rockets are actually odd-roc’s, so I’ve decided to post some photo’s of just a few in my collection. Yes, you’ve seen my night launch saucer, my dining room table w/ pizza,  and my collection of crayon rockets, but that’s just a small sample.  An odd-roc is any rocket design that isn’t the basic 3FNC, which is three fin’s and a nosecone. I’m a big saucer fan – in fact I’m beta testing Art Applewhite’s largest delta design to date – 36 inches in diameter. I’ll post a review after I’m finished with the build and first flight.  I also  found a kitchen sink at the dump the other day – that will be my ultimate test.

Thunderstruck

UPDATE: This will now be flying at LDRS 31 in New York. I’ve dramatically reworked the electronics so I can now house a professional high speed  HD camera in the gold exhaust port on the right side of the rocket.

Working on my major project for the Thundersrtuck Launch starting this Friday, March 30. Launch will be around 3pm March 30th.

This is a full size AGM-84 Harpoon Missile.

diameter: 11.5″
Height: 16 ft
weight: Approx 200 lbs fully loaded
motors: 3 6 grain 75mm M class motors,  ~ 20000 Ns total impulse (which makes it an “O” motor, my first!)

For perspective, that is an 8 foot ladder in the photo above

Thank goodness I’m in good shape – to get this photo I had to carry the two upper sections of the rocket solo up the ladder and into the booster.

Arduino controlled Saucer

 

I built this saucer for the annual MWP 9 Night launch. Since the night launch has a limited FAA altitude ceiling, traditional rockets just don’t cut it. The RGB LED’S on the saucer are controlled by an Arduino controller which I can control with my phone via Bluetooth. Cool to change the patterns while the saucer is on the pad.

Unfortunately, I wasn’t able to make the launch this year. Next year I plan on embedding the LED’S into the rocket in a matrix so I can transmit scrolling messages to the rocket from the pad kind of like this one, but much bigger