A burning question

 The Thrifty Rocketeer blog continues...

At a recent club launch, a new rockeeter showed up with a fairly elaborate two stage Estes rocket kit that he had assembled well.  The fins were on straight, and the parts of the rocket were all there.

However the startling thing about the kit was the complete lack of decals, decorations or paint.  Nada. Nothing.  No color.  No sealing.  Nothing.

Not wanting to discourage him on this extremely humid August day, we looked over the rocket and the range safety officer approved the rocket for launch.  He marched his rocket proudly out to the low power launch rods and threaded it down the rod, securing it with a clothes pin an inch or two above the blast shield.  The leads were attached and all was ready.

The new launch controller was in place and we were all learning its quirks and operation.  One thing that was different was the lack of a continuity tone, though each circuit had an indicator light for continuity.  That pale pink LED glowed, so we knew we were ready.

The range was checked and the skies were clear and so he was given the go ahead to begin  a short countdown.  At the zero hour, he pressed the button and... 

No joy.   The motor did not ignite.  No launch.

Connections were checked, and  we even switched launch circuits.  Again, no joy.

The launch control officer concluded that it must be the igniter and so turned off the power to the launch controller.  He and the young rocketeer walked out to the launch stand and checked.  There was a note of satisfaction in the LCO's voice and he proclaimed that was the problem.  He pointed out that the igniter had either come apart, or got just enough juice to burn through the igniter but failed to start the engine.

A new igniter was summoned and the LCO turned the failure into a learning opportunity to demonstrate how and why the igniter had to be in contact with the engine's black powder core.  And then all returned to behind the firing line.  Another countdown was held, after the LCO commented to all that were assembled that this was a heads up flight, as this was the maiden voyage of the rocket.

I caught the note in his voice, and understood that he wanted all eyes on the rocket for the launch, and so we all adjusted our positions so we had a clear view of the pad and the launch path.   

The countdown commenced and without any further ado, the rocket lept into the air.  It arced over, and just at the top of the flight, the ejection charge went off, separating the two stages and another layer of height was achieved.  As the rocket separated into it's component stages, I announced I was tracking the lowest stage.  Others tracked the chute and the upper stage.

Within a few moments, all were on the ground on our mowed field and the rocketeer ran out to collect his rocket.  I walked out and directly to the lower stage.  But he beat me to it and picked up the still smoldering stage.  Another rocketeer had collected the other stage and joined us for the walk back to the firing line.

But the young rocketeer was troubled by something.  The rocket was still smoldering and as he held it up, it looked like a rochshark test, where there was considerable center portion of the motor mount and fins missing.   Not being familiar with the rocket design I didn't see it at first, but he pointed out that much of his naked balsa rocket had burned away.

He was right,but I didn't know what to say to him.  Would a layer of paint have protected the stage? I didn't know.

We walked back to the firing line and he held it out for the LCO to examine, and that's when I noticed that the unit was STILL smouldering.  And it seemed to me that the burn pattern was even larger than when we had first seen it out in the field.

That's when it hit me.  It was still on fire.  The thin balsa was slowly being consumed by a slight burning layer that was being fed by the slight breeze over the field.  The rocket was literally being consumed as the rocketeer was carrying it home.

Quickly I moved to my table and picked up my water bottle. I pointed out what was happening to the fins and balsa and told him the only thing to do was to douse it, which I did.  And that's when I suggested that a good coat of paint would have sealed the balsa and retarded the creeping fire that had been eating his rocket up.  Of course, the slight dose of water I poured over it to extinguish it also was going to warp and ruin the rest of the balsa, but it was a done deal now.

I let the LCO take over with his analysis of the failure.  The motor thrust block had not been glued in well enough, so when the ejection charge blew, it drove the upper stage motor deeper into the body tube and the exhaust ignited the bare balsa.  It was on fire from that point on, though it still climbed and performed its arc well.

I turned to the sad rocketeer and reminded him that it was not a perfect hobby.  That you had to expect to have some losses along the way.  But that the value was in learning from each failure to improve your game.  He nodded, and walked the burned shell of his rocket toward their vehicle.   I suggested that he keep the rocket out of the car and on the ground in the shade to assure that a smouldering ember wasn't still ablaze inside, and he said he would.

I was sad for him, but realized this was the first time that I had ever seen a naked rocket burn. 

And I recalled the time some ten years earlier when I took my big red rocket while it was finishing gluing on the road trip for a two hour drive to the launch site.  Once there, I shot it with a rattle can base white primer coat and set it out in the stiff breeze to dry.  It took about a half an hour before I had shot it with a second layer of red accent paint and still had it hanging out to dry.

My neighboring rocketeer shook his head and said "Dude, you're supposed to finish painting at home, BEFORE you come out tot he field."  He was right, but I got the rocket finished that afternoon, and got it onto the pad.  It launched and was recovered well, the last flight of the day.

And so I remembered my cutting corners early in my rocket career and thought about the lessons learned.

Somehow, it seemed to bookend the experience.  

And I am left with the question:  Have you ever flown a naked rocket?  Why did you do that, and  what benefit did you gain from it?  The Thrifty Rocketeer wants to know...