Aftermath pictures of the Air Munuviana

Post-flight analysis, complete with photos showing in excruciating detail all the damage suffered in the crash.

Instead of my normal embedded pictures, these photos are clickable links to make it easier for those on dial-up. It's all in the extended entry.

Enjoy. Remember, you learn more from the failures than you do from the successes.

Someone in previous comments thought that it would've been cool to have pictures of the actual crash site. I didn't have the camera because I had no idea if I would be able to find the remains. The area the Air Mu went down in has some very wet meadowland, and it wasn't inconcievable that she might have hit and driven straight down into the mud, with anything left above ground hidden by tall grass. That, and the possible scramble through the woods for an unknown length of time just didn't make carrying the camera bag something I wanted to do.

This first picture is of the recovered pieces, laid out more or less in order. The long purple tube on the right side is the motor.

Bits and pieces

Now this next picture is interesting. First off, only one of the two on-board batteries were recovered, and as you can see, it's pretty messed up (upper right). Yep, that's a 9v, and yep, that's a big ol' dent in it.

Upper left is the altimeter and plywood mounting plate. Besides the splintered ends of the plywood, the main indication of impact is the circuit bits knocked free and just barely hanging on. Something not clear from the photos is that all those wires are snapped clean, but the terminal ends of each wire connection are still secure.

That green and yellow bit towards the bottom is the ejection canister. It consists of an electric match in a plastic container that holds the black powder ejection charge, and is fired by the altimeter. This one didn't. I know that because of that soggy mass of black and gray between the canister and the battery. That is the flame-proof wadding used to protect the parachute from the burning particles of the ejection charge when it goes off. All of that black is the unburnt black powder. The impact shattered the canister, the black powder wound up in the surrounding wadding, and the water soaked it all. I'm going to let it dry out a day or two and try test-firing the electric match.

Detail - bits and pieces

This next picture is of the nose cone, from the base looking up towards the point. See what I meant about the nose cone being flattened the long way? Notice the paint job. All that red didn't scrape off, it crackled from the deformation of the plastic and fell off in little bitty pieces. Also note the three holes in the base. I used 3/16" tubular nylon for the recovery harness, and it cut through the thick plastic like a cheese-slicer.

It used to be round, honest!

Here's a close up of the (now) two-piece motor tube. The dented bit of cardboard cylider is the motor mount adapter, and still has the aluminum tube and thick plastic fuel grain inside it! I couldn't get a good end-on picture, but the tube is out of round as well at the nozzle end (black bit on the upper right). The motor tube snapped just above the fuel grain, which basically runs the length of the cardboard adapter shown. The end of the bottom tube was plugged with almost 2" of mud. I dug it out to see where the floating injector wound up. It wasn't attached to the grain where it should be, and I was wondering if it hadn't been propelled forward into the upper end of the motor tube at impact. Nope, the injector wasn't recovered, it might still be laying on the bottom of that creek.

Motor tube(s)

So the final analysis doesn't give a clear answer as to what went wrong. The altimeter may have failed, although it's more likely that I did something wrong to cause the failure. I have some theories about that, and I'm going to have to give some serious thought to the steps I took during prep, and how to improve my methods. Face it, when a failure costs this much money, it's in my best interest to figure out best I can how not to do it again.

Posted by Ted at May 2, 2004 08:38 PM
Category: Rocketry