Search found 2219 matches

by OverTheTop
Wed Mar 22, 2017 6:41 am
Forum: Self Introductions
Topic: Greetings from SE Melbourne!
Replies: 6
Views: 107

Re: Greetings from SE Melbourne!

Welcome to the forum SFM. As to which topic to post to, just think where your question best fits. Sometimes there is no exactly right answer but it doesn't matter that much anyway. We are a friendly and tolerant bunch. My best guess to answer your question would be the low-power section, but if it i...
by OverTheTop
Tue Mar 21, 2017 5:42 pm
Forum: Scratch Built
Topic: Curing Oven questions
Replies: 52
Views: 1266

Re: Curing Oven questions

What's wrong with good old electro-mechanical relays? Only power dissipation is coil, not load related. Just asking the question...
by OverTheTop
Tue Mar 21, 2017 5:03 pm
Forum: Scratch Built
Topic: Curing Oven questions
Replies: 52
Views: 1266

Re: Curing Oven questions

I haven't had time to look at schematics in detail. Too busy. No rocketry since last November :( Sorry. I was just about to post about an earth. Always think safety. Any metalwork that can be touched should be earthed. Make absolutely sure the earth from the mains is connected to the metal. If you w...
by OverTheTop
Mon Mar 20, 2017 8:44 pm
Forum: How to's
Topic: Different Epoxy for Different purpose??
Replies: 6
Views: 208

Re: Different Epoxy for Different purpose??

I usually buy West Systems at Carbatec (http://www.carbatec.com.au) but they don't have a large range of hardeners or sizes. They do suit what I buy though. Probably worth a look. You local boat-building place can probably help too, although if you mention the word "marine" the price will ...
by OverTheTop
Sun Mar 19, 2017 5:23 pm
Forum: Self Introductions
Topic: Greetings from The Central Wheatbelt of WA....
Replies: 11
Views: 253

Re: Greetings from The Central Wheatbelt of WA....

Hello Chris, Welcome to the forum! Rocketry can be really addictive. Enjoy the journey from LPR to HPR, and use the process to get the wrinkles out of things as you work to HPR. A word of advice. Once you hear and see a HPR launch you will be hooked. I see you have a HAM license too, which will open...
by OverTheTop
Sun Mar 19, 2017 12:48 pm
Forum: Mid/High Powered Rocketry
Topic: MEC
Replies: 7
Views: 147

Re: MEC

One of our guys had something similar happen. Got run over by a combine harvester.

After eventually being returned to the owner it was shortened and renamed "Recombined" :D
by OverTheTop
Sun Mar 19, 2017 11:46 am
Forum: How to's
Topic: Different Epoxy for Different purpose??
Replies: 6
Views: 208

Re: Different Epoxy for Different purpose??

5 minute Araldite


Avoid it like the plague...
by OverTheTop
Sat Mar 18, 2017 6:51 pm
Forum: Mid/High Powered Rocketry
Topic: Stability, nose weight, and fin size at mach 1+ speeds
Replies: 25
Views: 388

Re: Stability, nose weight, and fin size at mach 1+ speeds

laminated to the hardware.


Watch the coefficients of thermal expansion differences if you do this. I suspect they will bite.
by OverTheTop
Sat Mar 18, 2017 6:43 pm
Forum: How to's
Topic: Different Epoxy for Different purpose??
Replies: 6
Views: 208

Re: Different Epoxy for Different purpose??

Hmm. Glue threads are always contentious. Many opinions. Data sheet is king. Know the specs and what you want to achieve. Having said that, there are rules of thumb. Personally I would use JB for anything in contact with the motor casing. Its higher temperature rating helps it keep its specification...
by OverTheTop
Sat Mar 18, 2017 8:57 am
Forum: Mid/High Powered Rocketry
Topic: Stability, nose weight, and fin size at mach 1+ speeds
Replies: 25
Views: 388

Re: Stability, nose weight, and fin size at mach 1+ speeds

My concern is that the significant thrust MAY cause a harmonic effect similar to fin flutter in the body tube, causing it to de-laminate so to speak from the motor hardware. I think you are right with the resonances here. I don't have a feel for where the likely failure point would be though. Maybe...
by OverTheTop
Fri Mar 17, 2017 5:16 pm
Forum: News & Events
Topic: Small drone 'shot with Patriot missile'
Replies: 5
Views: 165

Re: Small drone 'shot with Patriot missile'

The guy who launched it now has "Overkill" as his middle name...
by OverTheTop
Fri Mar 17, 2017 12:41 pm
Forum: Mid/High Powered Rocketry
Topic: Stability, nose weight, and fin size at mach 1+ speeds
Replies: 25
Views: 388

Re: Stability, nose weight, and fin size at mach 1+ speeds

I wouldn't sweat too much about heating etc at Mach 1.5. Things are pretty tame around that area. Here is a graph: SupersonicGraph.png Remember temperatures are absolute :? The thread with more discussion on this is here: https://forum.ausrocketry.com/viewtopic.php?f=6&t=5619 Fins do look quite ...
by OverTheTop
Wed Mar 15, 2017 8:23 pm
Forum: Mid/High Powered Rocketry
Topic: Stability, nose weight, and fin size at mach 1+ speeds
Replies: 25
Views: 388

Re: Stability, nose weight, and fin size at mach 1+ speeds

Can you post an image of the rocket please? I don't have OR. Simulations can be quite rough in the approximations of the build as far as thickness of materials etc, as long as the correct mass is used and the external dimensions are representative. Parachute size (packed) for a rough sim is mostly i...
by OverTheTop
Wed Mar 15, 2017 6:25 am
Forum: Mid/High Powered Rocketry
Topic: Stability, nose weight, and fin size at mach 1+ speeds
Replies: 25
Views: 388

Re: Stability, nose weight, and fin size at mach 1+ speeds

Do you have a graph of stability margin vs velocity from OR?
by OverTheTop
Mon Mar 13, 2017 10:36 am
Forum: Self Introductions
Topic: Newbie
Replies: 9
Views: 203

Re: Newbie

Hi Bazz. Welcome to the forum and the hobby of rocketry! Lots of helpful people linger around here, so if you have any questions just search and/or ask :) You are really in the middle of a lot of clubs, but none particularly close :( In Tripoli Rocketry Association we fly out of Serpentine (35km fro...

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