Joe Turner's 38mm Scratch-Build

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joeman
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Re: Joe Turner's 38mm Scratch-Build

Postby joeman » Mon Dec 10, 2018 9:48 pm

Thanks Snrkl,
I think that is the second time I've been caught out that way!


ok, on other news, I've been unable to locate my Buzzer, so I've created another one! The new one is a little louder than previous one and a little nicer looking in my opinion. I'll use this in the launch of this rocket.

IMG_7117_sml.jpg


Hope that spawns a few ideas!!
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

joeman
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Re: Joe Turner's 38mm Scratch-Build

Postby joeman » Fri Jan 04, 2019 9:27 am

Here are a few pictures of Some Fly-Away-Rails I've designed and printed.


They seem to work okay on the 1010 rail I have here.
i.e.
* With about additional 100 grams the "dummy" rocket slides down
* They open up promptly and in organized manner when "freed".

IMG_7269_sml.JPG
Overall appearance from side/back
IMG_7269_sml.JPG (200.69 KiB) Viewed 700 times


IMG_7270_sml.JPG
Clearance in T-Slot of 1010


[youtube]https://youtu.be/aEiiiI28YsI[/youtube]

Happy to share design with anyone.
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

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SpaceManMat
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Re: Joe Turner's 38mm Scratch-Build

Postby SpaceManMat » Fri Jan 04, 2019 11:06 pm

Nice one. Need to get my act together and do some 3D printing.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

joeman
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Re: Joe Turner's 38mm Scratch-Build

Postby joeman » Thu Jan 17, 2019 4:23 pm

Re parachute not inflating

Main charge fired at 800ft (and it did fire okay)

I followed:-

https://topflightrecoveryllc.homestead.com/Folding.html

And then I did fold over length wise to reduce total length... so yes I did add that step..... to reduce the total length.

I think if it was ejected without the cable cutter at apogee, it would inflate.


If the cable cutter was around the top part of the parachute, it might inflate (up to the cable cutter) at apogee. Then at 800ft, when MAIN fires the parachute may inflate completely.

Something to go over when I get back.

Thanks

Joe




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L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

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SpaceManMat
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Re: Joe Turner's 38mm Scratch-Build

Postby SpaceManMat » Thu Jan 17, 2019 6:17 pm

ok I think that final Z fold is not a good idea. If I needed to reduce the length I would do it after step 5, but I see they have an option to do that last but I don’t like how they’ve done it either. With the extra fold down internally placed it is basically trying to push open chute. You also want to have the outer edge of chute to be as large as possible - that is wrapping around everything else. You want the edge of the chute to catch the flow of air as it goes around the bundle, this is what opens it. Hope that makes sense.

Was there actually an issue with the cable cutter? The photo is not a great resolution so I cannot see if something is wrapped around the chute or not. I’ve not used a cable cutter but I would consider opening higher.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

joeman
Rocket Crew
Rocket Crew
Posts: 355
Joined: Fri Mar 06, 2015 9:05 am

Re: Joe Turner's 38mm Scratch-Build

Postby joeman » Tue Jan 22, 2019 10:11 pm

Thanks SpaceManMat.

Sorry for the delay. Finally back home and have the rocket and a little bit of time.

Firstly, here are better quality photos

IMG_7387_sml.JPG
Found cable cutter under large nomex blanket. Has fired okay. (no trace of cable tie)


IMG_7385_sml.JPG
Higher resolution picture of recovery gear.
IMG_7385_sml.JPG (242.46 KiB) Viewed 553 times


The way I folded it was using the alternative 6,7 step at the end + Z-Folds. The fact that the Z-Fold still shows makes me think you are right about the Z-Folds not being the best idea.


RE: Folding procedures
You also want to have the outer edge of chute to be as large as possible - that is wrapping around everything else.


I don't follow what you are saying 100%, though I get the idea about trying to catch the flow of air, to get some drag, to start the inflation.


RE: Alternative Procedure
Do you think the standard (6), (7) steps might have a better chance at opening up?
I know I can adjust the length of the bundle at the first step (6) by overlapping those folds a little, before proceeding to step 7.
I'm thinking it might be a bit better because when the parachute starts to unfurl, it isn't so streamline, when compared to the other folding method. It may lead to more drag potentially.....and a larger 'area' of bottom of skirt is exposed to air, which could assist opening...gores more likely to flutter and start the main inflation....See my very rough photo below.

IMG_7682_sml.JPG
Quick mock up of chute unfurling


What do you think?


RE: MAIN deployment
I'll definitely be setting the cable cutter charge (MAIN) for 1500ft at Thunda2.

All a very humbling experience.


Appreciate your feedback.
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

joeman
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Re: Joe Turner's 38mm Scratch-Build

Postby joeman » Sat Feb 02, 2019 10:01 pm

Hi,
I've been extremely time poor, so I've been very slow at getting into the post flight analysis.

Managed to manually "fuse" the altimeter data with the GPS data to get an approximate plot of the flight.

Flight_Path_sml.png
Flight_Path_sml.png (220.67 KiB) Viewed 434 times


The plot looks on the face of it to accurately represent the flight - almost perfect up and the place it landed looks "about right"

I was able to get data every 2 seconds from the rocket from beginning to end. Happy with that.


p.s. Is there mobile reception at Thunda2?
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO


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