vlcsnap-2017-04-22-20h52m29s153.png
Likes Like
RocketEZI-65
Launches1
Flight StatusSuccess
Event
NEFAR-TRA Research Launch 2017-04-22
Altitude8736 ft
2662.73m
Expected9700 ft
2956.56m
Velocity612 MPH
985.32km/h
Velocity Exp.603 MPH
970.83km/h
Gs Actual8.6
Gs Expected7.8
Wind Speed5.0MPH
8.05km/h
S 180°
Weight6.43lb.
2.92kg
StageMotor
1 K270

First Aerotech

2017-04-22 17:59:14Z

Insane Rocketry

Likefileicon launch170422_135452_451.csv

Stratologger

Likefileicon PFComputer1.pf2 Likefileicon PFComputer2.pf2

Description

Lots of spectators at half-blast, but not a lot of flyers. This allowed me to have unexpected time to prep my rocket for flying.

I had just purchased 54mm 2560 Aerotech hardware so this is the first major launch using Aerotech RMS style motor. For my thoughts on Aerotech, read the comments below.

Winds were gentle from the southern direction.

Assembly of the rocket went smoothly. I installed the phone into the bay, closed the bay, installed the sheer pins and was just about ready to take my rocket to the pad when I heard a phone call come in. Oddly, I heard my app mention it had gone to the background on receipt of a phone call. Normally when you receive a call, you see a display of the call, but the foreground running app is not pushed to the background. Everything appeared to recover fine, but I was afraid I would not receive video since Android requires your app to be in the foreground to record video. Later, I found that if you receive a call marked as a SPAM, the OS temporarily pushes the foreground app to the background to give you better WARNING of the spam call.

I decided to remove the sheer pins, open the bay and inspect the phone. All of course was fine, inspection or reboot or change of the phone app was completely unnecessary. At least I had peace of mind the app would record video. I love the onboard 4k video.

Due to this random act of unluckiness, I have now added to the app a voice message letting me know that app is back in the foreground. Had this message been in there, I would have known everything was fine and continued to the launch pad.

I was fairly fatigued between assembly of the new motor and the oddity of the App so I was real careful taking my rocket to the pad, arming the electronics, confirming battery strength, etc.

While waiting for my rocket in the launch queue and being fatigued, I didn't notice a large cloud had drifted overhead or I would have told LCO to hold off until it passed. This is unfortunate as I don't like punching holes in large clouds. The launch was spectacular, but did go through a cloud.

Voice from the GRMS radio was intermittent due to an shoddy connection with the phone. This lead to us having no clue where the rocket was until after touch-down. Next time I'll stick to bluetooth to connect to the GRMS radio, the connection has proven itself reliable. I like testing different configurations to increase my launch options. This is critical learning for when I go out west for my one chance shot of launching really high. Plus I love experimenting.

Recovery was easy and was not that far away. Using the web page from the Kindle was awesome as it is so easy to view in bright sun. A little less launch angle would have landed the rocket right on the field. Rotation was gentle, but did pick up speed nearing apogee, maybe due to wind.

Lessons Learned:

  1. Use a bluetooth connection, or get different microphone jacks that snap in better.
  2. I now am confident assembling Aerotech 54mm hardware.
  3. The phone was unusually hot this launch. My guess is it is due to my bay redesign having a really nice shock absorbing foam resting up against the entire front of the phone's glass. This is acting as an insulator and not allowing the phone to dissipate heat. I'll shave off about a quarter inch of the foam, install vertical balsa ribs covered in graphite(for heat dissipation) so there is some air space between the foam and the phone. While it stayed 20 degrees cooler than overheating, the battery temperature was 120 degrees and that is just too hot. In the summer it would surely overheat.
  4. I need to add a thin amount of epoxy to widen to the lower electronics bay bulkhead to widen it slightly as there is too much gap and ejection charge is seeping through.

 

Comments

frewi80
Like 2017-04-27 22:22:28Z

Your phone was hot but did not shut off...Did you do the mod on that phone to keep it cool(er)..?

esotericdude on 2017-04-27 12:39:38Z wrote:

I finally added a detailed launch description to this launch.

esotericdude
Like 2017-04-27 23:24:08Z

My Nexus 5x does not need the mod that yours needs - the Nexus 4 has the lack of the CPU heatsink and that's what I would be installing. It won't take me long at all to "fix" your phone, I just need it for a night so I can take it apart. The Nexus 4 should have always had a heatsink but they must have wanted to save a few cents in manufacturing. It's unfortunate because other than that, it is a VERY nice phone. I made the same mod as I would make to yours on another test phone that I have, and the cpu operates much cooler (I found an app to display cpu temperature to test)

However, I do need to modify the insulation on the back side (the foam shock absorber I made) to allow the phone to breath so it stays cooler. The phone battery will operate up to 140 degrees. At that point it shuts down the phone so the battery doesn't melt down or damage the electronics. The battery warmed to 120 degrees, this is the first "warmer" style weather I have had with the newly designed bay, so it makes sense that it is the first time I noticed I had an issue. There is a real good chance with my current bay my phone would overheat in 93-95 degree weather as there is nowhere for the heat to go with a "pillow" next to half of the phone.

I'll post pix of the mods to the foam when I do it - I'll shaving a quarter inch of the foam off, adding balsa (or basswood) vertical ribs and gluing graphite to the ribs to help dissipate heat.

frewi80 on 2017-04-27 22:22:28Z wrote:

Your phone was hot but did not shut off...Did you do the mod on that phone to keep it cool(er)..?

esotericdude
Like 2017-04-29 16:40:44Z

8518da3f20244f44Md.jpg
Like

The case protector for the Nexus 5x phone seems to be the #1 contributor to it not disappating heat. I have cut some holes over the battery and cpu to help it stay cool. It has already shown a significant change in the amount of heat the phone operates at.
 
I want to keep it on as it does provide less chance of pushing a button while loading the phone in the rocket and gives a bit of shock absorption.
 
I looked at the Nexus 5x teardown to find out where the battery and CPU were located to find out where to cut the case protector.
frewi80
Like 2017-04-29 16:53:57Z

Jeez Surgery...... reminds me to go to the doctor... haha

esotericdude on 2017-04-29 16:40:44Z wrote:

 

8518da3f20244f44Md.jpg
Like
like.png

 

The case protector for the Nexus 5x phone seems to be the #1 contributor to it not disappating heat. I have cut some holes over the battery and cpu to help it stay cool. It has already shown a significant change in the amount of heat the phone operates at.

timcub
Like 2017-06-28 13:09:18Z

One thing I have observed at NEFAR is that seem to launch thru clouds. Yours was not the only one that day!


Video


Like

Like

Images

vlcsnap-2017-04-22-20h52m29s153.png
Like
IMG_0308.JPG
Like
IMG_0309.JPG
Like
_DSC3185.JPG
Like
_DSC3186.JPG
Like
_DSC3187.JPG
Like
_DSC3188.JPG
Like
_DSC3189.JPG
Like
_DSC3190.JPG
Like
_DSC3191.JPG
Like
_DSC3192.JPG
Like
5099a57db0654cd8Org.jpg
Like
5be7cc6b14754638Org.jpg
Like
ca74146a4c7a4a0cOrg.jpg
Like
cb9882e28dd14686Org.jpg
Like
353c3c0d9c6e4dafOrg.jpg
Like
f745bf2cda414526Org.jpg
Like
vlcsnap-2017-04-23-16h50m06s156.png
Like
vlcsnap-2017-04-23-16h52m16s224.png
Like
vlcsnap-2017-04-23-16h53m10s111.png
Like
vlcsnap-2017-04-23-16h53m29s112.png
Like
vlcsnap-2017-04-23-16h53m48s115.png
Like
vlcsnap-2017-04-23-16h53m59s115.png
Like
vlcsnap-2017-04-25-20h51m36s70.png
Like
vlcsnap-2017-04-25-20h52m08s166.png
Like
vlcsnap-2017-04-25-20h52m47s99.png
Like
vlcsnap-2017-04-25-20h53m43s68.png
Like
vlcsnap-2017-04-25-20h54m04s187.png
Like
vlcsnap-2017-04-25-20h54m55s127.png
Like
18121632_10210830739942883_5991288484670233528_o.jpg
Like
18121939_10210830735622775_4011474931521789045_o.jpg
Like
18121099_10210830737502822_3813724010412231427_o.jpg
Like
18077305_10210830737982834_1313124215476671916_o.jpg
Like
18076995_10210830738222840_6583988567404854910_o.jpg
Like
18077101_10210830738742853_894090241170069784_o.jpg
Like
18121042_10210830739262866_5430379932345829321_o.jpg
Like
18121861_10210830739502872_5365284601102527746_o.jpg
Like
18121632_10210830739942883_5991288484670233528_o.jpg
Like