Search found 1679 matches

by saefroch
Mon May 04, 2015 2:44 pm
Forum: General How-To & Discussion
Topic: Is spudding dead?
Replies: 102
Views: 28525

Re: Is spudding dead?

I don't think spudding is dead, but I can only speak for myself here. I've been busy at college for the past 4 years, and am now heading off to a PhD program. I'm trying to put together a little project for the college I'm leaving, so maybe that'll appear here. mobile does have a good point; I think...
by saefroch
Fri Nov 30, 2012 10:21 pm
Forum: Hybrid Cannons
Topic: U Tube Manometer
Replies: 8
Views: 1586

You could try to pull this off just for kicks, but a normal pressure gauge will have higher accuracy, occupy less space, be more durable (not subject to orientation), and probably also cost less.
by saefroch
Fri Nov 30, 2012 12:13 am
Forum: Off-Topic Hobbies
Topic: "Offtopic-posts-topic" NSFW
Replies: 6630
Views: 289776

A gaming/performance PC will deliver far better graphics and performance.

Actually.
by saefroch
Thu Nov 29, 2012 11:47 pm
Forum: Hybrid Cannons
Topic: Trident Mk. II Build Log
Replies: 131
Views: 11433

Day 2 of machining, good progress. New pump completed, 3/8" diameter head, 12" stroke: http://img824.imageshack.us/img824/7107/newpump.jpg Sorry for the terrible picture quality, all I have at school is my cell phone. The weld is not mine. I've also discovered that if I ask nicely, the school will p...
by saefroch
Wed Nov 28, 2012 10:41 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 108277

Manufacturer ratings are usually extremely pessimistic. Do you have any idea how much sch XXH pipe weighs?

I think spark plugs typically have machine threads, which are in no way compatible with pipe threads. I was unable to find an adapter anywhere.
by saefroch
Wed Nov 28, 2012 8:54 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 108277

I have no idea what XXH is. You should really be good with sch 80, but again I'd use an online calculator or have somebody here spit out some numbers for you.

Few spark plugs have NPT threads. You'll have to look on ebay if you want to find any. I found some 1/2" NPT spark plugs there a while back.
by saefroch
Wed Nov 28, 2012 8:26 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 108277

At sufficiently high pressures, a failure will occur. Do some quick reading via wikipedia on shear stress/shear modulus and tensile stress/Young's modulus. There's also compressive stress/bulk modulus, but at the level most of us are at we don't bother considering it. If you're wondering if your spe...
by saefroch
Wed Nov 28, 2012 4:31 pm
Forum: Hybrid Cannons
Topic: Trident Mk. II Build Log
Replies: 131
Views: 11433

Day 1 of machining done, pump cylinder reamed to 3/8", and pump rod almost to exact size (~0.002" left on it).

Tomorrow should see a finished small high-pressure pump.
by saefroch
Wed Nov 28, 2012 10:16 am
Forum: General How-To & Discussion
Topic: GGDT/HGDT Request Thread
Replies: 108
Views: 19885

Here you be:
Image
or 370m
Image
or 457m
by saefroch
Wed Nov 28, 2012 12:53 am
Forum: General How-To & Discussion
Topic: GGDT/HGDT Request Thread
Replies: 108
Views: 19885

HGDT is crashing on me, need to re-read part of the chapter to finish this homework. I'll try to have you something before I hit the hay.
by saefroch
Wed Nov 28, 2012 12:20 am
Forum: General How-To & Discussion
Topic: GGDT/HGDT Request Thread
Replies: 108
Views: 19885

45 degree launch angle is not the optimal launch angle for a high-velocity golf ball. http://imageshack.us/a/img16/2678/build1.png http://imageshack.us/a/img138/107/build1ballistics.png http://imageshack.us/a/img189/8366/bulid2.png http://imageshack.us/a/img819/9530/build2ballistics.png Your golf ba...
by saefroch
Tue Nov 27, 2012 10:42 pm
Forum: Hybrid Cannons
Topic: HGDT Max Bar Pres > Cham Pres
Replies: 5
Views: 854

I recall previous discussion about there eventually being a 1-D version of HGDT, and issues with GGDT near-supersonic. Yeah, I wasn't asking if it was true to the real world, but if I hit upon a bug. I'll keep your caution in mind. I believe DYI ran some numbers for me a while ago that put the press...
by saefroch
Tue Nov 27, 2012 9:52 pm
Forum: Hybrid Cannons
Topic: HGDT Max Bar Pres > Cham Pres
Replies: 5
Views: 854

So this is accurate?

Based on the graph of barrel pressure over time (I can't even see the peak that goes up to 6.5kpsi), will the barrel's inertia take care of this extra pressure?
by saefroch
Tue Nov 27, 2012 9:49 pm
Forum: General How-To & Discussion
Topic: why can't I get a better result when firing?
Replies: 4
Views: 640

A neophyte! Welcome! You're looking for the section called "Combustion Cannon Discussion," in particular a sticky called How to Build a Propane Meter . To actually answer your question: No, using propane will be no more reproducible than other propellants if you're trying to gauge the mix by feel. Y...
by saefroch
Tue Nov 27, 2012 7:52 pm
Forum: Hybrid Cannons
Topic: HGDT Max Bar Pres > Cham Pres
Replies: 5
Views: 854

HGDT Max Bar Pres > Cham Pres

This is the hoped configuration for my current build. Why is the max barrel pressure much greater than the max chamber pressure?

Image