[RocketsNW] Parachute protection options

Sun Nov 16 00:36:39 PST 2008

> just go for a scale v2 landimg

Ah, but to be truly scale that involves 'payloads' prohibited by the
safety code!
:-)

+McG+

> --- On Fri, 11/14/08, kmcgoffin at worldaccessnet.com
> <kmcgoffin at worldaccessnet.com> wrote:
>
> From: kmcgoffin at worldaccessnet.com <kmcgoffin at worldaccessnet.com>
> Subject: Re: [RocketsNW] Parachute protection options
> To: "Greg Deputy" <greg at blastzone.com>
> Cc: rockets at rocketsnw.com
> Date: Friday, November 14, 2008, 12:07 AM
>
> Which is my feeling about pistons in rockets.  Tube materials that
> swell/shrink with changes in temperature or humidity, slightly
> out-of-round tubes, BP crud sticking to critical surfaces, cumulative
> invisible but significant damage during landings...you'd better be
> prepared to put in significant TLC to ensure proper functioning.
>
> Pistons have their place in rocket recovery systems, but not in little
> stuff 'n shoot fun-time rockets.
> +McG+
>
>
>> No doubt!  When you're talking about thousands of an inch for the
> diameter
>> of your piston, etc, its time to move on!
>>
>> -----Original Message-----
>> From: rockets-bounces at rocketsnw.com
>> [mailto:rockets-bounces at rocketsnw.com]
>> On Behalf Of Bloom, Steven E
>> Sent: Wednesday, November 12, 2008 1:28 PM
>> To: Simpsonclark at aol.com; foreveryoung at inlandnet.com;
>> kmcgoffin at worldaccessnet.com; Mfreptiles at aol.com
>> Cc: rockets at rocketsnw.com
>> Subject: Re: [RocketsNW] Parachute protection options
>>
>> or just wrap it in a burrito and toss in a handfull of dog barf.....
>>
>> :>)
>>
>> ________________________________
>>
>> From: Simpsonclark at aol.com [mailto:Simpsonclark at aol.com]
>> Sent: Wednesday, November 12, 2008 9:36 AM
>> To: Bloom, Steven E; foreveryoung at inlandnet.com;
>> kmcgoffin at worldaccessnet.com; Mfreptiles at aol.com
>> Cc: rockets at rocketsnw.com
>> Subject: Re: [RocketsNW] Parachute protection options
>>
>>
>> Graphite or glass composite pistons molded to match the inside of the
>> glass body tube and then sealed with an O-ring in a simple sawn and
>> filed groove can maintain 3 or 4 thousandths radial clearance, which is
>> the recommended clearance.  That won't grab a rolled and
> shroud-wrapped
>> chute. The pistons can be molded by draping a cylinder with wet glass
>> and pushing it to the bottom of a release-coated short piece of body
>> tube and then setting it on a release-coated surface, ideally a convexly
>> curved surface.  I have no standard preference respecting the
>> installation orientation.  Lube the body tube with silicone grease.
>> -Robert
>>
>> In a message dated 11/11/2008 12:35:04 P.M. Pacific Daylight Time,
>> steven.e.bloom at boeing.com writes:
>>
>> 	You have cardboard pistons in your vehicle and compressor?!?!???
>>
>> 	Seriously :>),  The tolerances, surface smoothness, and lack of
>> a rag (parachute) laying on top of the piston make comparison.....
>> incomparable.
>>
>> 	steve
>>
>> 	-----Original Message-----
>> 	From: Bryan Young [mailto:foreveryoung at inlandnet.com]
>> 	Sent: Tuesday, November 11, 2008 11:26 AM
>> 	To: kmcgoffin at worldaccessnet.com; Mfreptiles at aol.com
>> 	Cc: rockets at rocketsnw.com
>> 	Subject: Re: [RocketsNW] Parachute protection options
>>
>> 	It sounds like I need to learn how pistons are designed -- they
>> seem to work well enough in my air compressor and vehicles. Are there
>> any references that contain piston design that I could look into?
>> 	-B
>>
>> 	-----Original Message-----
>> 	From: rockets-bounces at rocketsnw.com
>> [mailto:rockets-bounces at rocketsnw.com]
>> 	On Behalf Of kmcgoffin at worldaccessnet.com
>> 	Sent: Tuesday, November 11, 2008 2:19 AM
>> 	To: Mfreptiles at aol.com
>> 	Cc: rockets at rocketsnw.com
>> 	Subject: Re: [RocketsNW] Parachute protection options
>>
>> 	Yes, it seems to be a delicate balance between having enough
>> clearance to avoid binding, and having too much clearance that can catch
>> the parachute or allow the piston to tilt enough to 'catch'.
> It's a
>> rather fault-intolerant design. Best suited for rockets made with high
>> grade materials and given lots of TLC before launch.  Not good for
>> "stuff another motor in and fly 'er" type hobby rockets.
>>
>> 	That may have something to do with why I was never a regular
>> user of piston ejection.  :-)
>> 	+McG+
>>
>>
>> 	> In a message dated 11/9/2008 2:50:17 A.M. Pacific Standard
>> Time,
>> 	> kmcgoffin at worldaccessnet.com writes:
>> 	> (I always wondered why the parachute didn't bind between the
>> piston
>> 	> and body tube.)  I dunno.
>> 	>
>> 	> It sometimes does, especially with overzealous sanding of the
>> piston
>> 	> skirt.  The larger the airframe diameter, the more likely this
>> can
>> 	> happen since tolerances are usually greater.
>> 	>
>> 	> Mike F.
>> 	> AOL Search: Your one stop for directions, recipes and all
>> other
>> 	> Holiday needs.
>> 	>
>>
>> http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=
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>>
>> ://searchblog.aol.com/2008/11/04/happy-holidays-from-aol-search/?ncid=em
>> lcnt
>> 	ussear00000001
>> 	> Search Now
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