Have Pink

AstronMike said:

What motor did you use here? I wonder if maybe the elevons had a tad of flutter (maybe not even noticable) and that stressed/displaced your servos? What if you made the next flight with a 'low-n-slow' motor just to confirm the overall controllability of the craft?

Click to expand...

It was a CTI H100. Got 400' on it. Don't get much slower or lower for a 7 lbs bird :=)

Ari.

I decided to repair Have Pink and fly it again. I started cleaning gunk off the heat shield and had an AHA moment. I had thought that the tear in the aluminum foil happened at ignition, when the initial fireball came out of the nozzle. It looked excessive, but that was my best guess. Having cleaned up the soot today, I formed a different theory.

It appears that the glider folded 90 degrees at impact, and the nozzle made an impression in the heat shield. Creases in the foam show where it folded. It's amazing that the foam/laminate sandwich can fold this far and then unfold again without breaking. I know the creases were there and were going to need reinforcement, but I hadn't realized how far the front of the glider had bent.

Ari.

Good to see its going to fly again Ari!

If I may make a recommendation; being a glider club member I know those guys fuss over installing wipers in the wing to aileron/flapperon gap, in this case elevon gap. Have Pink's gap although streamlined is large and likely creates eddes along its length. Those eddes are not just a source of drag but can form and collapse rapidly helping the onset of flutter. IMHO. Ergo I would suggest the installation of wipers for Have Pink.


Richard

Thank you for your suggestion Richard.

I put 1/4"x3/4"x14" wood reinforcements into the foam where it bent to recover rigidity around the crease.

I cut slots in the foam with a box cutter, then oull the foam out with a flat screwdriver. I've found the secret to clean cuts in foam: fresh blades.

Polyurethane glues expand as the foam up. Every time I use Gorilla glue, I remind myself that I need less than I think. Then I put more than I need. Every time :=)

I tape up the slots after glue and wood are in. Paper tape holds the foaming glue mostly inside the slot, rather than allowing it to seep out and become useless.

Bricks hold the airframe from arching up (the crease wants to pull the nose back up). Paper bag keeps bricks from sliding off the slippery plastic lamination.

Ari.

Sanded excess foam and applied a laminate patch. It's hard to see in the photo, but it's there.

Ari.

Here's the video from XPRS, finally.

[video=youtube;KZGKKOin4l0]https://www.youtube.com/watch?v=KZGKKOin4l0[/video]

And a photo by Dean Walton.

Ari.

Nice flight, Ari! These big rocket gliders are few and far apart and fun to watch. Were you doing some controlling during the boost phase on the second flight? The reflective tape makes it look like there several motors burning. Cool!

I know! The first flight, I went "oh ****, did I blow the nozzle, or burn through the side wall, there are three flames coming out of the rocket!" Then I figured out it was reflections.

On the second flight I flew the glider under thrust. I65 has a very regressive thrust profile, and it surprised me. I thought the motor was done thrusting, but it kept going and going--though with diminishing thrust.

Ari.

+1 Good show man!


Richard

That's pretty awesome. Congrats on the successful flights. It's good to have the crash behind you.

I have, especially after watching your gliders, decided that I am going to build a large rocket boosted sailplane for my L2.

Did you have problems with the exhaust obscuring the glider? It pretty much disappears from view of the camera, but I don't know where you were standing.

TheAviator said:

Did you have problems with the exhaust obscuring the glider? It pretty much disappears from view of the camera, but I don't know where you were standing.

Click to expand...

It was terrible, especially on the second flight. The glider rolled 180 degrees on boost and I didn't notice (trembles at the memory).

Ari.

The flight looks awesome till it disappears from camera.

Has anyone tried launching an autonomous glider with an IMU on board to bring it back to the launch site? Would you run into regulatory issues with the FAA regarding drones?

Have Pink flew at TCC October Skies.

It had two great flights yesterday, on I140 and J90. Steve Jurvetson snapped these two photos of the J90 flight. I have video that I'm editing.

This morning, I flew Have Pink on J180 and it crashed. It appears that a servo arm failed from aerodynamic loads when I tried to correct trajectory under boost, and an elevon came loose, and the airframe failed structurally. The video I have of this flight is less clear but I plan to post that too.

The later crash notwithstanding, Have Pink achieved a milestone for me: successful flight and recovery of an L2 glider.

Ari.

Cap'n Jim (qquake2k) posted video from Saturday in his report along with photos: https://www.rocketryforum.com/showt...CC-October-Skies-10-18-14&p=776147#post776147

[video=youtube;Q4Rs6RU6mOw]https://www.youtube.com/watch?v=Q4Rs6RU6mOw[/video]

Thank you Jim!

Ari.

Ari, Terrific flights! In the video it looks like the glider is diving to pick up air speed. You know you've got a good model, when you can turn around and make multiple flights in a short amount of time.

Congrats on the milestone and that first flight. Do you plan to rebuild her?


Ricvhard

Ari, first of all, *epic* congrats on getting HP over "The Threshold of Exceedingly Few"!!

I'm guessing that video above is of the I140, right? I have six of these, and flown one, but it CATO'ed. Destroyed the 4" Bomarc's pod, but thankfully, the glider managed to burn off the excessive airspeed and glide back in, albeit too close to the cars.

I've only flown one J90, back in the '95ish time frame, and that was cool. Did use a J180 as my first shot over an I back in the day, but after a perfect boost, Excelsior did not transition well and 'Tomcatted' in, damaging the front tubing some.

Sorry to hear of Have Pink's ultimate fate though, been there. Just like Vulcan's legacy, HP 'did its job', so to speak, to which you walk a little prouder.

Congratulations again, Ari. BTW, did you have to control the boost any on the J90's ascent? I'm guessing probably, since getting something like this to boost hands-off for a 9 sec burn is not good on the nervous system. Can't wait to see the video of this!

All of the flights were awesome! I especially liked the J90 --- that is such a long burn, and it's great to see that huge model being flown under power for such a long boost. I'm sorry about the crash because of the loss of a great glider, but it at least it was a spectacular disaster!

J90 flight from Saturday. Video credit: Amy Rosenthal.

[video=youtube_share;1hW2U95OyCk]https://youtu.be/1hW2U95OyCk[/video]

That was an awesome flight Ari!

That J90 flight was great! I'm glad there's video of that one!

WoW! Did you get a log of the altitude for the J90 flight?


Richard

I had intermittent data from the altimeter and took it out before that flight. The scientific answer is "pretty high" :=)

Ari.

A few more photos from Steve Jurvetson. More of his TCC photos appear at https://www.flickr.com/photos/jurvetson/sets/72157600239816068 and general rocket photos at https://www.flickr.com/photos/jurvetson/sets/5956.

Here, AT J90W.

Ari.

And AT J180T. This is the accident flight.

Ari.

It really came apart. Looks like you've discovered the Do Not Exceed Speed of Pink [foam] [sorry :blush: ] Looks like the nose broke at the old repair, has the servo come loose or just the elevon?


Richard

A servo arm broke. As far as I can tell, this is the first failure; everything else followed.

Ari.