CanSat Deployment Failure

[Ken Biba]

This photo is from University of ElectroCommunications presentation.    It clearly shows a Cansat failure entwined with a broken carrier, protective Nomex and Kevlar harness.

It was their first flight - I do not know who flew it ...   but one other item for us to improve.

K

[Richard Hagen]

Pic not opening for me, but it's likely my flight.

BP charge deployed both carrier and nosecone, BUT
the project was tied by string to the carrier and never came out. My main chute snagged on one of it's own shrouds and never fully inflated. The whole mess came down pretty fast, carrier landed first and was quickly demolished by the incoming main body. 

RH

---

From: Ken Biba <ken...@gmail.com>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 11:14:08 AM
Subject: [ARLISS Flyers] CanSat Deployment Failure

[Ken Biba]

Great poster child photo to inform students of possible dangers of tying to the carrier.

K

On Sep 21, 2011, at 11:32 AM, Richard Hagen wrote:

> Pic not opening for me, but it's likely my flight.
>
> BP charge deployed both carrier and nosecone, BUT
> the project was tied by string to the carrier and never came out. My main chute snagged on one of it's own shrouds and never fully inflated. The whole mess came down pretty fast, carrier landed first and was quickly demolished by the incoming main body.
>
> RH
>

> From: Ken Biba <ken...@gmail.com>
> To: arliss...@googlegroups.com
> Sent: Wed, September 21, 2011 11:14:08 AM
> Subject: [ARLISS Flyers] CanSat Deployment Failure
>
> This photo is from University of ElectroCommunications presentation. It clearly shows a Cansat failure entwined with a broken carrier, protective Nomex and Kevlar harness.
>

> <PastedGraphic-2.tiff>

[Richard Hagen]

Univ. of Electrocommunications problem was that they used double string and when it didn't pull out their release pin, it was strong enough to support the weight of the project. Based on what we saw in my camp, tying things to the carriers was pretty common this year. It caused several teams to request holes be drilled in the carriers to tie their string through and led to one cute exchange with Seth.

Student brought a parachute by post-flight with a small burn hole and stated "you burn hole in parachute".
Seth responded "yes, but you drill hole in carrier".

RH

---

From: Ken Biba <ken...@gmail.com>
To: arliss...@googlegroups.com

Sent: Wed, September 21, 2011 11:54:21 AM
Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

[Steve Wigfield]

I think we need make it clear, that no holes should be drilled in the bottom of the carriers. We could provide an attachment eye if they need an anchor.

 

Steve

 

 

---

[Richard Hagen]

These devices with the pull-pin are a plastic sleeve that wraps the entire project.  It runs the length of the carrier with a bunch of rings on the two ends. The "pin" is a 10" long chopstick that when threaded through all the rings holds the plastic sheet in the shape of a cylinder. Once the pin is pulled and the Mylar sheet unwinds the project is released.

In short, the whole thing is a plastic container that lets the project pop out once removed. Isn't that pretty much what the carrier does?

RH

---

From: Steve Wigfield <swi...@att.net>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 2:10:28 PM
Subject: RE: [ARLISS Flyers] CanSat Deployment Failure

[William Kellermann]

Now you sound like a design engineer.  Question, does the ‘pin’ require taper or would a dowel work just as well?  And is the chopstick used?
--
William Kellermann
wt...@comcast.net

---

From: Richard Hagen <di...@redglarerockets.com>
Reply-To: <arliss...@googlegroups.com>
Date: Wed, 21 Sep 2011 15:22:44 -0700 (PDT)

[Jamie]

Interesting – so the mylar just falls free or does it remain attached to the carrier as well?

 

I think a small wood eyebolt would do the trick (I often have an assortment of them).

[Richard Hagen]

The chopstick-like pin on the one that snagged was ornamentally grooved, but
probably not significantly tapered. I suspect it was the surface detail that
prevented it from sliding easily through the rings. I didn't notice any evidence
of prior use as an eating utensil. Perhaps Ken could resend the pic in some
other format. Not sure if the pin is visible since I couldn't open the pic.

A dowel would work, but my real question is why use the wrapping device at all.
The folded project is adequately restrained by the carrier and would spring out
into it's operating mode quite nicely as it slid out of the carrier.

---

From: William Kellermann <wt...@comcast.net>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 3:35:08 PM

[Steve Wigfield]

Is the pull pin attached to the carrier or the nose cone?

[save children]

OK OK Richard that is the best international exchange I have herd in some time, thanks. last year one of mine wanted to drill and I handed them a piece of gorilla tape. a small eye would be fine.

---

Date: Wed, 21 Sep 2011 13:59:00 -0700
From: di...@redglarerockets.com

Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

To: arliss...@googlegroups.com

[save children]

i flew this cansat last year and they had it wrapped in a clear film with a chopstick like pin and it would pull upon deployment of the project chute and the plastic dropped away. I think this was the winners last year.

 
Charlie 
 

---

Date: Wed, 21 Sep 2011 16:03:39 -0700
From: di...@redglarerockets.com

Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

To: arliss...@googlegroups.com

[Richard Hagen]

The carrier

---

From: Steve Wigfield <swi...@att.net>
To: arliss...@googlegroups.com

Sent: Wed, September 21, 2011 4:07:34 PM

[david raimondi]

The string is also used to pull a jumper off so that the start up sequence in the cansat can begin, or to simply let the sat know it has been deployed.

 

dave

[Jamie]

So – should we add an eyebolt anchor to the carrier specification?

[Richard Hagen]

Once upon a time, there was an 8-32 Pem nut in the center of the inner floor to receive the center stud of the can-sat divider. When the hang gliders first became popular, I remember securing parachute bag strings under the head of a fastener screwed into that hole.

RH

---

From: Jamie <ja...@dph.com>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 5:12:14 PM

[Bob Feretich]

I have flown OpenSats with a deployment filament the last two years. Last year's team drilled a very small hole (1/16") in the bottom of the carrier and tied the filament to the u-bracket on the bottom bulkhead. When this years team requested a hole be drilled, I gave them last years carrier (with the old filament still attached) and they attached their filament the same way last year's team did.

Regards,
Bob

[save children]

He y Richard that is a use for us old rocketeers, showing the young ones how to fly well and prosper.

 
Charlie 
 

---

Date: Wed, 21 Sep 2011 18:39:31 -0700
From: bob.fe...@rafresearch.com

[Jonathan DuBose]

I have flown number of projects that required a attachment point in the carrier.  The first was 4 years ago and I have used it each year until this year.  I flew it twice last year both with same team.  The gizmo which looks alot like Ken's "poster child" crashed once but worked the second time although they had a broken wheel.

 

Flew the same team this year but they had a different setup. No attachment.  They deployed the rover and navigated back to the flag although it took and very long time as they scribed a huge arc while getting there.

 

I didn't write down the name of the team (which I usually do) but they clearly changed something from last year.

 

Jonathan 

From: Bob Feretich <bob.fe...@rafresearch.com>
To: arliss...@googlegroups.com
Sent: Wednesday, September 21, 2011 6:39 PM
Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

I have flown OpenSats with a deployment filament the last two years. Last year's team drilled a very small hole (1/16") in the bottom of the carrier and tied the filament to the u-bracket on the bottom bulkhead. When this years team requested a hole be drilled, I gave them last years carrier (with the old filament still attached) and they attached their filament the same way last year's team did.

Regards,
Bob

On 9/21/2011 5:29 PM, Richard Hagen wrote:

Once upon a time, there was an 8-32 Pem nut in the center of the inner floor to receive the center stud of the can-sat divider. When the hang gliders first became popular, I remember securing parachute bag strings under the head of a fastener screwed into that hole.

RH

From: Jamie <ja...@dph.com>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 5:12:14 PM
Subject: RE: [ARLISS Flyers] CanSat Deployment Failure

So – should we add an eyebolt anchor to the carrier specification?

 

From: arliss...@googlegroups.com [mailto:arliss...@googlegroups.com] On Behalf Of david raimondi
Sent: Wednesday, September 21, 2011 5:00 PM
To: arliss...@googlegroups.com
Subject: RE: [ARLISS Flyers] CanSat Deployment Failure

 

The string is also used to pull a jumper off so that the start up sequence in the cansat can begin, or to simply let the sat know it has been deployed.

 

dave

-----Original Message-----
From: arliss...@googlegroups.com [mailto:arliss...@googlegroups.com]On Behalf Of Richard Hagen
Sent: Wednesday, September 21, 2011 15:23
To: arliss...@googlegroups.com
Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

These devices with the pull-pin are a plastic sleeve that wraps the entire project.  It runs the length of the carrier with a bunch of rings on the two ends. The "pin" is a 10" long chopstick that when threaded through all the rings holds the plastic sheet in the shape of a cylinder. Once the pin is pulled and the Mylar sheet unwinds the project is released.

In short, the whole thing is a plastic container that lets the project pop out once removed. Isn't that pretty much what the carrier does?

RH

From: Steve Wigfield <swi...@att.net>
To: arliss...@googlegroups.com
Sent: Wed, September 21, 2011 2:10:28 PM
Subject: RE: [ARLISS Flyers] CanSat Deployment Failure

I think we need make it clear, that no holes should be drilled in the bottom of the carriers. We could provide an attachment eye if they need an anchor.

 

Steve

 

 

From: arliss...@googlegroups.com [mailto: arliss...@googlegroups.com ] On Behalf Of Richard Hagen
Sent: Wednesday, September 21, 2011 1:59 PM
To: arliss...@googlegroups.com
Subject: Re: [ARLISS Flyers] CanSat Deployment Failure

 

Univ. of Electrocommunications problem was that they used double string and when it didn't pull out their release pin, it was strong enough to support the weight of the project. Based on what we saw in my camp, tying things to the carriers was pretty common this year. It caused several teams to request holes be drilled in the carriers to tie their string through and led to one cute exchange with Seth.

Student brought a parachute by post-flight with a small burn hole and stated "you burn hole in parachute".
Seth responded "yes, but you drill hole in carrier".

RH