Airframe choices (or why you should consider rolling your own airframes)

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Viking
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby Viking » Tue May 22, 2018 1:32 pm

My brother-in-law builds some impressive boards for some of the best surfers in the world

Hmmm, long shot here, but his surname wouldn't be Burger would it?
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby drew » Wed May 23, 2018 9:40 am

03flyer wrote:My brother-in-law builds some impressive boards for some of the best surfers in the world and is also helping me with building some light weight tubes.
I don’t care about data, records,recognition or glory ... I’m free from that BS.


One of my favourite parts of this hobby is that what motivates people to build and fly rockets often varies greatly. And I think that's a good thing.
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03flyer
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby 03flyer » Wed May 23, 2018 10:21 pm

Viking wrote:
My brother-in-law builds some impressive boards for some of the best surfers in the world

Hmmm, long shot here, but his surname wouldn't be Burger would it?


See you at Aus Thunda 19 with my hexagon(chicken wire) foam tubes.
I don’t know what the burger reference means an explanation would be nice... but I’ve surfed some nice waves at Margaret River.

Thank you, Drew. :D
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby Viking » Thu May 24, 2018 1:23 am

Was simply asking if his surname is Burger. Nothing more to it than that. But you've answered my question.
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby Oldboy » Thu May 24, 2018 11:19 pm

If using chicken wire to lay glass over ,
1, Would that cause any interference to electronics ,ie tracking ?
2,I have made things using similar process, but is this acceptable with the minimum use of metal in our hobby ?
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby drew » Fri May 25, 2018 12:36 pm

Oldboy wrote:If using chicken wire to lay glass over ,
1, Would that cause any interference to electronics ,ie tracking ?


Yea, that definitely sounds like a perfect design for a Faraday cage airframe to me.
Andrew Hamilton
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AMRS Records Committee Chairman
Max Alt AGL - 23,908ft - K300 - Balls 22
Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby OverTheTop » Fri Jun 01, 2018 7:07 pm

Oldboy wrote:If using chicken wire to lay glass over ,
1, Would that cause any interference to electronics ,ie tracking ?
2,I have made things using similar process, but is this acceptable with the minimum use of metal in our hobby ?
Queries to the of knowledgeable folks with in our hobby


Depends on the size of the chickens you are filtering with the wire. Holes in mesh allow EM waves (and chickens) to pass if sized sufficiently large.

Proximity of the antenna to the mesh also affects attenuation and radiation pattern.

Sorry, I don't have any rules-of-thumb that I know of, or much knowledge in that area generally. An EM field simulator would probably be my first port of call if I were delving into this. Personally I would probably not put any trackers inside it, or maybe choose a different composite. Another alternative is to build some and do a range test.

If the mesh composite is structural, I would not think any RSO would have a problem with flying the rocket. The mesh is probably not a large proportion of the mass.
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby joeman » Wed Jun 13, 2018 6:58 am

Hello,
I've decided I'm going to roll my own air-frame for the next rocket.

I've been looking high/low for a supplier of tubes that could sell me something to use as a Mandrel - 38mm.

AusRocketry sell couplers, but all small sizes. Nothing long enough to roll on.

What are others using as a Mandrel? Can anyone suggest a possible supplier?

Thanks!

Joe
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L2 - March Fly (1633K940) - 18-Mar-2018

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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby OverTheTop » Wed Jun 13, 2018 7:36 am

AusRocketry sell couplers, but all small sizes. Nothing long enough to roll on.


Email Blake at info@ausrocketry.com and ask for whatever length you want. He gets longer tubes and cuts them to size. Don't forget to make it a little longer than you actually need as the ends of hand-rolled tube are normally a bit rough and trimmed off.
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby drew » Wed Jun 13, 2018 9:48 am

joeman wrote:I've been looking high/low for a supplier of tubes that could sell me something to use as a Mandrel - 38mm.

AusRocketry sell couplers, but all small sizes. Nothing long enough to roll on.


I've always used phenolic and bluetube "motor mount" tubes sourced from Blake. As OTT said, drop Ausrocketry an email.
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Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby Viking » Wed Jun 13, 2018 12:36 pm

What they said.
For non-critical diameters I just use PVC pipe, but sounds like you want to go MD.
joeman wrote:...Nothing long enough to roll on.

Is 915mm too short?
You could get two PML tubes and carefully join them.
https://ausrocketry.com.au/couplers/phe ... -5-36.html
or there's 1220mm BT:
https://ausrocketry.com.au/couplers/blu ... upler.html
Simon
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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby joeman » Wed Jun 13, 2018 3:15 pm

Hi Guys,
Yep, MD.

RE: Length
I was hoping to create one tube that I could then cut the switch-band and air-frame from...so I know they will have a nice fit.
I've assumed first 50mm of each end are "waste", so when i add it up...it does add up to over 1m.
[When I have a bit more to show..... I'll start up a build thread]

I have managed to find Aluminum tubes - 38.1mm (Capral in Cairns) - which happens to be same diameter as the PRO38 cases. Not sure how straight they are. I'll find out. Still might give Blake a tingle

Guess it is a case of build a few tubes and check to see how things fit and improve as one goes along. Patience and persistence.



Cheers!
Joe
L1 - Callisto (H133) - 11-Jan-2016 - LCO
L2 - March Fly (1633K940) - 18-Mar-2018

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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby drew » Wed Jun 13, 2018 3:21 pm

Viking wrote:What they said.
For non-critical diameters I just use PVC pipe, but sounds like you want to go MD.
joeman wrote:...Nothing long enough to roll on.

Is 915mm too short?
You could get two PML tubes and carefully join them.
https://ausrocketry.com.au/couplers/phe ... -5-36.html
or there's 1220mm BT:
https://ausrocketry.com.au/couplers/blu ... upler.html


Well done mate! Obviously my search skills aren't up to scratch.

FYI from my understanding blue-tube has a tendency to bend/warp. Just keep that in mind. And if you want to join two phenolic tubes to make one long mandrel then you can use coupler stiffner tubes. That's what I'll be using for my 75mm MD airframes when I start rolling them in 6-8 weeks. They only come in 54mm and larger sizes though.

https://ausrocketry.com.au/catalogsearch/result/?order=name&dir=asc&q=Stiffener+
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 23,908ft - K300 - Balls 22
Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

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Re: Airframe choices (or why you should consider rolling your own airframes)

Postby Viking » Thu Jun 14, 2018 5:06 pm

drew wrote:...And if you want to join two phenolic tubes to make one long mandrel then you can use coupler stiffner tubes...
https://ausrocketry.com.au/catalogsearch/result/?order=name&dir=asc&q=Stiffener+


Interesting. 'Stiffy™' are new to me. Cool.
Simon
WARS #24 / AMRS #54 L2


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