Disappearing Act: Minimum-mass I1299 rocket

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Disappearing Act has... grown the beard?
It has a mop of hair now.

Or rather, some chopped CF painted on with Aeropoxy ES6209 to protect the newly reshaped balsa from crushing like what happened when it hit the lakebed.

IMG_20130129_215459.jpg


I'll smooth it out some more tomorrow.
 
I wouldn't worry about the balsa crushing, unless it hits a lake bed again. I use a shaped foam nose cone with a coating of laminating epoxy on me L1 rocket. I ended up flying it on a I1299N-P twice. The nose cone was not a problem. Stripping the rail guides off was, but not the nose cone.

My last flight of L1 on a I1299 was billed as the Disappearing Rocket and it really lived up to the name. It only pulled 80G, 560 mph at 130 ft.,motor burnout. But I used an old thermalite igniter. When the button is pushed, you get a flash of flame and smoke as the thermalite ignites, then nothing for 1 to 2 seconds as it burns up inside the plastic tube. When it hits the pyrogen at the top of the igniter, the rocket is gone!. That one to two second delay has people looking away and speculating about a bad igniter. When they hear the BOOM and look back, it's too late. The rocket is gone! Disappeared!

Have fun. I1299 Warp-9 motors are really cool in minimum diameter, light rockets!
 
Handeman said:
I wouldn't worry about the balsa crushing, unless it hits a lake bed again. I use a shaped foam nose cone with a coating of laminating epoxy on me L1 rocket. I ended up flying it on a I1299N-P twice. The nose cone was not a problem. Stripping the rail guides off was, but not the nose cone.

My last flight of L1 on a I1299 was billed as the Disappearing Rocket and it really lived up to the name. It only pulled 80G, 560 mph at 130 ft.,motor burnout. But I used an old thermalite igniter. When the button is pushed, you get a flash of flame and smoke as the thermalite ignites, then nothing for 1 to 2 seconds as it burns up inside the plastic tube. When it hits the pyrogen at the top of the igniter, the rocket is gone!. That one to two second delay has people looking away and speculating about a bad igniter. When they hear the BOOM and look back, it's too late. The rocket is gone! Disappeared!

Have fun. I1299 Warp-9 motors are really cool in minimum diameter, light rockets!
Click to expand...

The balsa is destined to hit the lakebed again, twice. I fly on a lakebed, after all.

If the weather is good, I think I will pull out the I1299 and fly it again after the I59wn instead of waiting another month.

You sound like you've seen one of these motors flying in a minimum diameter light rocket before. Have you?
 
It's.... tailcone time!

13+-+1


13+-+2


It weighs but nine grams, and is held into the Aerotech aft closure by three setscrews tapped diagonally. The half-angle of the cone is ten degrees.
 
Current simulations say 16673 feet, with its almost exact actual weight of 1.89 pounds loaded.
Surprisingly, according to RASAero, it's below optimum mass: it seems to think that weighting it to 2.11 pounds would send it to 16795 feet. I didn't expect that with this motor's thrust profile. For the flight, though, I probably won't weigh it down other than perhaps with a lot of foil tape.
 
Today, I installed and programmed the Tripoli Raven2, and I bonded the I1299 grains to the liner with Aeropoxy ES6209.
 
Will it fly at Lucerne this weekend? I'm LCOing in the morning, and would love to push the button on this one. :D
 
Thrustify said:
Will it fly at Lucerne this weekend? I'm LCOing in the morning, and would love to push the button on this one. :D
Click to expand...

I intend to fly it on an I59 first, and then spend 15 minutes swapping out the altitude record altimeter, deal with the paperwork, and then fly it on the I1299.
 
Just remember...pics or it didn't happen!

(can't wait to see this fly - you've put a mess of work into it!)
 
GL Saturday. I won't be making it out 'til March. You and Chris gotta come to FAR soon, got some great rockets going up there ;)
 
Today I put my nosecone on a lathe to sand it super smooth. I discovered it was waaaaaaaay not straight, possibly partly explaining why its flight on an I49 went off-vertical.

So I put on a really sharp, high-rake lathe tool (it was on a metal lathe) and cut it straight (and somewhat pointier) and sanded it smooth, covered some of the rough spots with filler, accelerated the drying with a heat gun, sanded it smooth and to shape, and then recoated the whole nosecone in ES6209. It's curing now.


Regarding photos, if I end up flying (I'm not flying the I1299 before the I59 record flight, and that's not happening if it's too windy), I'll be taking video with my camera at 60fps and a padcam GoPro Hero3 Black at 240 fps.
 
cwbullet said:
Very nice tail cone. I have gotta get that skill.
Click to expand...

Actually, I messed up a little, and took a photo from an angle that hides the blemishes (which are minor anyway).

I set the compound on the lathe to bore the inside at an angle in order to remove the most weight. When I finished boring it, the tool was farther from the rotation axis than the small end of the tailcone, but I moved the tool straight to the right so it yanked the part out of the jaws, thus bending it out just a tad and making a lovely helical scratch on the inside.
 
Handeman: Your signature says more about you than your Dad. My humble bow.
 
Last edited:
So.

I made two flights today.

I flew on an I59wn, and it weathercocked a lot and soared into the distance. For fear of being given difficulties with the record, I did not use the tailcone. It accelerated startlingly quickly, and made quite a racket, with a few pops during the burn. Because of the weathercocking, it only achieved 10250 feet.

Fun fact: the altimeter beeped out 65531 feet. I was perplexed by this.

The nose was a bit bashed up on the lakebed, but then I decided to load up the I1299.

It was... ridiculous. CCotner who is sitting behind me just said "it sounded like it was trying to rip a hole in the sky". The burn was longer than I expected, but man did it haul butt.

It was surprisingly easy to follow by eye, but even so it unfortunately lived it up to its name and I have not found it.

Well, it survived structurally, but I am not sure what went wrong. There was no tracking signal at all once I had put my camera down and grabbed the receiver, but I am not sure the rocket hadn't landed already at that point.

One possibility is that the boost destroyed the electronics or the batteries. My most probable explanation is that the apogee ejection charge fell apart under boost, despite the tape I used to hold it in place.

Lessons learned: make the av-bay stronger even at the expense of weight, and include accommodations for fixing the ejection charge.
 
I took these videos, and a friend who came to the launch got the stills.

I59WN for record:

IMG_1715_shrunk.jpg

[video=youtube;Aps3QeDskSs]https://www.youtube.com/watch?v=Aps3QeDskSs[/video]

IMG_1738_crop.JPG

IMG_1739_crop.jpg

There was a bit of a spike at the burnout of the White Lightning grain.
IMG_1744_crop.jpg

I1299N for MAX ACCELERATION

[video=youtube;cHLVNc1KgIA]https://www.youtube.com/watch?v=cHLVNc1KgIA[/video]

HOW ON EARTH DID SHE CATCH THIS SHOT

IMG_1815_crop.JPG



High framerate GoPro pad videos should follow sometime.
 
That was awesome. It really jumped out of that tower.

So sorry you didn't find it...doubly frustrating for the electronics inside to be lost, I'm sure.
 
As I've heard many many times, never launch something you're not willing to lose. Any idea if there was a deployment on the I1299 shot?
 
edwinshap1 said:
As I've heard many many times, never launch something you're not willing to lose. Any idea if there was a deployment on the I1299 shot?
Click to expand...

I have no idea. The deployments have never been within visible range on any of its flights.

I am planning on finding it next month, though. With data from CCotner's Talon with GPS, we might be able to find the exact wind direction from right before my flight and calculate a landing zone.
 
Congrats to CarVac for a flippin' AWESOME pair of flights.

We think that it's highly, highly unlikely that no one would have seen it downrange (where everyone's rockets were landing) if it had deployed correctly. Based on the I59 flight data, the video listed above (which gives a good idea of launch angle), and near-ground winds aloft from my GPS flight half an hour earlier or so, we're going to make a splashdown plot, possibly one each for chute- and chute-at-apogee. Sometime in the future we'll drive out there again (it's only 90min or so), and go looking. We found a collection of incredibly hilarious and random junk and adorably depressing model rockets today; we'll go looking again, aided by GPS, and math. :)
 
Fun facts about the Disappearing Act:
  • Launching Crater: 4.5" deep by 14" wide
  • Number of cameras recording takeoff: 4
  • 72 frames of 240fps video
  • Distance from rocket where Rail Stop was recovered: ~10 feet
  • Distortion of Launch Tower Legs: ~ 2"
  • Time to clear 4' Launch Tower: 0.050s (12 frames @ 240FPS)
  • Length of Flame: 36"
  • Flame-to-rocket ratio: ~1.5
  • Absent FIPa file's worth: Priceless
 
Last edited:
i1299_flame.JPG

Given that two 60d's were turned upon the launch tower in stills mode at full continuous drive mode (5 fps), I guess there was a 50% chance that at least one would capture the rocket in the tower.
 
Ssssssssssssslllllllllllllllllllloooooooooooooowww wwwwwwmmmmmmmmoooooooooo:

[video=youtube;QtNmVub01MY]https://www.youtube.com/watch?v=QtNmVub01MY[/video]

This is 1/16 speed from 240 fps video (equals 15 fps output).

Things to note: The tower flexes downward a significant amount, causing the end of the leg rails to rise by an inch or so.

The triangular aluminum rail stop, which was screwed firmly into one of the guide rails, got blown down the rail, off the bottom, and was found fifteen feet away. You can see it spinning violently in the video.
 
MarkH said:
Congrats on the I record! Sorry to hear about the I1299 flight, though it looked pretty awesome from the video. Hope you find it.

The 65,531 altimeter reading is pretty close to 2^16. I seem to remember someone else reporting an altimeter reading similar to this once and it was explained as a negative ASL reading at liftoff and some bit limitation of the altimeter (perhaps 16 bit), and something with the LSB or MSB. I can't seem to find the thread at the moment.
Click to expand...

iirc, 65535 is the maximum decimal representation of a 16 bit integer (2^16-1).

That slo-mo take off is just fabulous. The rail stop and debris field is so crisp it looks computer generated.
 

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