|Rocket Electronics & Recovery|
|Launch & Static Tests|
|Motor Class Table|
|Iowa Amateur Rocketry Group|
|Don't Click Here!|
|Grain||Propellant Weight||Tube Length||Propellant Length||Density|
|Totals||6.7786||19.0||17.8"||0.06567 lb/cu in|
Throat Diameter: .86"
Core Diameter: 1.27"
Grain Length: ~4.45"
Grain Diameter: 3.0"
Kn: 202, 215, 187
Core to Throat Ratio: 2.18 to 1
Expected Total Impulse: 847 pound seconds
With grains cast, I decided to prep the recovery system so I could fly at the next possible opportunity. I added a few pictures and info about the redesigned recovery system on the Defiance Recovery page. It was a challenge packing and prepping the recovery module, in fact, I had one problem as I was trying to insert the module into the upper air frame. After I slid it in, I was trying to adjust the module in the upper tube to align the bolt holes, and the sucker was just stuck in there. I ended up removing the timer pull wire penatrators and pushing the module out the bottom of the upper tube. I think the bolt holes in the upper tube flared out some, and caught on the o-ring in the recovery module. So I put an extension on my cylinder hone and cleaned up the inside of the upper body tube. After honing the upper tube, the module slid in very easy and I had no problems aligning the bolt holes.
I left all the altimeter and timer settings the same as the last flight, only I changed the ARB3D to audible beep rather than LED. It was too hard to see the LED's in the ambient pressure port, much easier to hear the beeps when the unit is turned on. Both altimeters have an e-match going to the PIRM2, the PIRM2 has about a .8 gram charge.
I decided to launch a day earlier than originally planned, the wind was brisk, but the forecast was calling for even more wind the next day. Bill was on hand to help out, so we headed out to the launch site shortly after lunch. I was somewhat concerned about launching the rocket in even modest winds, as the rocket is really heavy for the motor I'm using and very overstable with such a light propellant load. But I decided to go ahead with the launch as there wasn't anything within range of the rocket to harm.
We set up the launch pad 300' from the rocket. I finally retired "Old Blue" (my van) so I moved my new (to me) Blazer back behind the launch pad. It really is easier to leave the vehicle and trailer connected, that was one nice thing about Old Blue, you just didn't care if a motor cato'd next to it!
Bill was at the launch controller. All clear. 5,4,3,2,1 and ignition!
Click Here for the video of the flight, first few seconds of the liftoff from the big Panasonic camera, rest of the fight from the Sony camera. 5 MB for 1 minute 12 second video.
Here's a neat video of the deployment of the drogue chute. I deinterlaced the video and slowed it down 75%. What happened is the rocket was arcing over and still had significant horizontal velocity at the moment of drogue deployment. The drogue deploys and trails behind the rocket, once the drogue opens the rocket pulls the drogue along for a short distance, then the rocket gets flipped around by the drag of the drogue. Pretty rare to get video of such a large rocket under these circumstances.
The "L" class motor in the Defiance lights quickly and kicks up a nice pile of dirt in the process.
This is just a few moments after the apogee charge goes off.
Now the drogue is deployed and the rocket is swinging a lot under it.
We missed the video of the main deploying as a tree was in the way. This picture was taken shortly after the PIRM2 fired and released the main.
After the main deployed the rocket settled into a nice controlled descent. This is a picture just before landing. The rocket doesn't look that far away, it's a big rocket and a big chute! The rocket landed a long way into the corn field.
Here's the blast crater the 6.6 pounds of propellant in the "L" motor made. Just imagine what the 58 pounds of propellant in the "O" motor will do.
The flight was very marginal, as I had expected the higher winds caused some instability in the flight. The rocket weather cocked a lot, did some gravity turning and a little wobbling. At the point of drogue deployment the rocket was flying almost horizontally and at a pretty fast speed. Despite that, the drogue deployed nominally with no problems. You may have noticed, only one of the two drogues deployed. When I got home with the rocket I checked out the cause, it seems my battery on the timer just didn't have enough juice left to fire two e-matches. The timer is certainly capable of firing two e-matches, but it needs current to do that, and one used battery didn't do the trick. In fact, the battery was only sourcing about 1.6 amps when I got back. I suppose I should double up those batteries just to be on the safe side.
Everything else worked as planned. The PIRM2, as usual performed flawlessly and everything was recovered intact. The rocket drifted a long way, the wind must have been over 25 mph above ground level. So we had one long walk in the corn field to recover the rocket. To make matters worse, much of the corn was laid flat on the ground from high winds earlier this summer. The radio locating system again worked great, we walked right up to the rocket. It was carrying the rocket out that wasn't amusing at all!
The Transolve P6K reported 2,100', the ARB3D reported apogee at 1,963'. I've got a Missile Works RRCX 40K on back order at the moment. I really wanted to use it on this flight, because the P6K isn't really designed for flights over 25,000'. All said and done it was a good test of the deployment system, other than adding another battery for time power, I think I'll leave things alone for the full propellant load flight. I still haven't found a launch site suitable for a high altitude flight, so I'm not sure when I'll be able to fly the Defiance again.