Mumbles Posted October 30, 2007 Posted October 30, 2007 The thing that throws me is that the poof just doesn't seem big enough to be an ounce and a half of lift.
cplmac Posted October 31, 2007 Posted October 31, 2007 There was nothing on top of it. The mortar was only four inches tall at that point, and there was nothing but air over it, I found the shell wrap about fifty feet away.
WarezWally Posted November 8, 2007 Posted November 8, 2007 What a shit night, had one great opportunity to shoot what i wanted and everything sucked, from my rockets to my shells. Had 2 rockets fail on me tonight: This one was a 1lb made with my new swanky pyrotooling, fuel was some crap i had laying around that was fairly slow. Any ideas what went wrong? This one had a 50g dummy header. Was not happy with the nozzle (was crumbly and and a bit thick) and it crumpled the tube a bit. Looks to me like a blowout This one was made with my Chinese tooling (with the nozzle drilled out), tube recovered intact and is perfect, nozzle held out well. Was 1lb with no header. Same fuel as above.
Mumbles Posted November 8, 2007 Posted November 8, 2007 Yep, looks like the nozzle blew out on the first one. I'd suggest ramming/pressing harder. This may involve two things. First thing you may need is a reinforcing sleeve. 1lb rockets are a bit big to be trying to press without a sleeve. Secondly, you may want to invest in some good tubes. This may help solve the crumpling problem, which can become an issue. You don't mention if you're ramming or pressing, but I'd suggest pressing with something of this size.
Aquarius Posted November 8, 2007 Posted November 8, 2007 What kind of nozzle/endcap mix are you using? Bentonite, kitty litter etc.I have had the same problems: My rockets works well, rammed with a sleeve, hand rolled tubes, and when cutting down on the endcap, they blow... I wonder when I will learn, I made the same mistake twise, trying to fix things that are not broken....
WarezWally Posted November 9, 2007 Posted November 9, 2007 I used kittly litter which is pretty much pure bentonite, I didn't bother grinding it up so I just used the small pieces. http://www.ihaveadotcom.com/cart/index.php...products_id=256 Those are the tubes im using
Mumbles Posted November 9, 2007 Posted November 9, 2007 I like Phil, and certainly don't want to take any business away from him. However, those tubes are not the best for rocketry. Spiral wound is by far weaker than convolute. After you use them up, you may want to look into these. They certainly have their uses however. http://www.hobbyhorse.com/pyro_tubes.shtml They are comparably priced, and leaps and bounds higher quality. $32 vs $30 for the same quantity of tubes.
WarezWally Posted November 9, 2007 Posted November 9, 2007 Shipping is a killer though, they ship via FedEx.
Mumbles Posted November 9, 2007 Posted November 9, 2007 Jim is very reasonable. Give him an e-mail, and I'm sure he will accomodate you. If not, send me a private message, and I can work something out for you.
WarezWally Posted November 9, 2007 Posted November 9, 2007 Thanks for the offer, im not ready to rule out my tubes just yet
Tweetybird88 Posted November 9, 2007 Posted November 9, 2007 Shipping is a killer though, they ship via FedEx.I don't think so. I found this at the top of their page: Note: disregard the computer calculated shipping. You will be charged actual UPS shipping to your zip code.
Tweetybird88 Posted November 9, 2007 Posted November 9, 2007 oh, ok. I'm not a big fan of the united parcel smashers myself. Give me the good ole' usps any day. I have never had a single problem with them.
qwezxc12 Posted November 27, 2007 Posted November 27, 2007 When I realized I hadn't made a rocket in a while, I knocked together a 3lb. endburner from some Poplar BP I had laying around. I spiked it with +5% 5μm Al to heat it up some...too much, I guess. I made a Slow-mo of the CATO... 3lb endburner CATO The 15g salute header went sailing off into the woods and went off ~3 seconds later, so I guess the passfire worked o.k.
hst45 Posted November 27, 2007 Posted November 27, 2007 I spiked it with +5% 5?m Al to heat it up some...too much, I guess."You think you used enough dynamite there Butch?", (Butch Cassidy and the Sundance Kid, Robert Redford and Paul Newman) Thanks for the slow-mo video. I love the way the camera starts to move upward to watch the brilliant assent of the rocket, and then the action shifts dramatically downward. I know the feeling....I've been working on stingers lately and I have the fuel/nozzle ratio dialed in to send the little guys into orbit. I was bragging to a buddy about them, so I made a few at his house and they went great. Unfortunatly....as I NOW know... this particular combination won't lift shit, so when I tried a rather stout whistle mix header the little bugger went up about half way, nosed over, and headed towards the driveway, blowing about 20 feet above my pickup. No harm done, and a good laugh, at my expense, was had by all. Your shells look great, by the way (see ariel shell thread). Sorry that the 209's didn't pop. Great breaks.
qwezxc12 Posted November 30, 2007 Posted November 30, 2007 I was working on converting the remainder of the shell videos from last weekend, and I thought a slow-motion view of the mortar launches would be cool...so here's a quick video of 3, 4, 6, and 8in mortar launches slowed down to 15% speed. You can see my stand-of distance increasing with each subsequent jump in mortar size...self preservation kicking in. For reference, the trees behind the mortar rack are 16-18 ft. tall, I would guess...those 6 and 8in throw a bit of flame Video Sorry you couldn't make it hst...I guess I'll just have to bring some out to NH next time I'm out that way...maybe by then, I'll have the 8in'ers dialed in a little better.
h&k machineguns Posted December 16, 2007 Author Posted December 16, 2007 can't remember if I posted this before. I was cleaning out the garage and I found an old thick paper tube I had something shipped to me in. I didn't want to toss it so I decided to make a rocket body from it. I grabbed a few other cheap and easy things from the house and within 10 minutes I had this rocket. Of course the motor took me about 8 minutes to build and had hardly any delay. If I knew it was going to fly like it did I would have added a inch or 2 of comp above the core.This was a 76/23/1-3 AND 64/32/1-3 Fuel motor . Anyway things you do when your bored. http://pyrobin.com/files/.75%20id%20motor%...%20body%201.wmv
cplmac Posted December 16, 2007 Posted December 16, 2007 I got this error HK Not Found The requested URL /files/.75 was not found on this server.
rocket Posted December 16, 2007 Posted December 16, 2007 I got this error HK Not Found The requested URL /files/.75 was not found on this server. You need to copy the hole link into your address bar. "http://pyrobin.com/files/.75 id motor with body 1.wmv"
h&k machineguns Posted December 16, 2007 Author Posted December 16, 2007 Ya I don't know why it divided it like that after pasting it .
cplmac Posted December 17, 2007 Posted December 17, 2007 Nicely done as usual HK, not bad for ten minutes.
h&k machineguns Posted December 17, 2007 Author Posted December 17, 2007 Thanks, as soon as I find a 15-20' tube I am going to try it again. I think I can get at least 200 feet out of it, but man that thing will be super long. Probably have to stand on top of a truck cab to mount it on the long rod .
psyco_1322 Posted December 19, 2007 Posted December 19, 2007 Here a pic of the rocket I made and the convention, as you can hear in the video everyone was wanting to see teh thing go, it failed to work right. Now there is a 24oz bottle of trimethyl borate out in that field somewhere. For referance im bout 6'2" or so and it was a 3lb. rocket. http://www.apcforum.net/files/PGI_07_a018.jpg - pic http://www.apcforum.net/files/3lb-nozzleless-greenghost.wmv - Video http://www.apcforum.net/files/PGI_07_a019asdf.JPG - The circled one are some that we made up. You can see one with a small 8oz acetone header that worked just fine.
Stinger Posted December 25, 2007 Posted December 25, 2007 Hi all I made my first succesfull stinger yesterday and I was quite surprised that it worked so good Here are a few dimensions of the casing and noozle: 16mm ID tube, homemade5cm long3mm thick wallsThe venthole had 3mm ID, coated with sodiumsilicateVertical noozle had 4mm ID.The core was 2,5cm long. The fuel I used was made from a slowburning blackpowder.I grinded it with a mortar&pestle. Here is a pre-firing picture:http://img95.imageshack.us/img95/781/s8001582wx9.th.jpg And here is the video: http://www.youtube.com/profile?user=BackjardPyrotechnics The take-off wasn`t very powerfull, but it could be better due to the slow blackpowder I used.Merry christmas to all, Stinger
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