#541
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Thanks, guys. Everything gets dealt with eventually. Nothing as serious as the real problems some of our members are experiencing.
The easy one (but expensive) was the lightning strike in the front yard (third one on that tree in the last 25 years) in July that blew the phone line out of the ground (literally) and scared the bejesus out of the wife. Note for reference - surge protectors (or UPS) are not lightning arrestors and the phone line is vulnerable even if buried. Just depends on where the lightning connects. This one missed the powerlines so only stuff connected to the phone line was affected. This, of course, just after my decadal computer upgrade in June. So - I replaced all the phones, got a new phone line (temp service in 2 days, permanent line took two weeks), replaced the brand new modem, and replaced the brand new computer (though we did save the old drive and data). Eating beans and weenies for a bit - we run high insurance deductibles here in hurricane country. Sometimes stuff just happens ... Yogi |
#542
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Falcon 9 v1.1 or some actual modelling
Been a bit of a dry spell but I'm getting caught up with reality. So, a bit of time for creating some small simulations.
SpaceX is living up to its reputation with the first development of the Falcon 9, the 1.1 version. In house design/build to increase the Falcon's cost effectiveness. They've redesigned the engine mounts (octa-web) added a big plug to lengthen the first stage tankage and a smaller one to the second stage. All else remains (mostly) the same. Some info on a "larger" payload fairing but the quoted specs seem to match what I've already done. Makes for one heck of a flaming toothpick. Yogi (it all seems to fit so far ...) |
#543
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I have a question for you Yogi if I may. How high do your rockets fly? I remember when my son Mathew was real young some one bought him a rocket set with launching stand and remote switch to fire it off. Solid fuel rockets and man would those suckers fly high. I thought we lost he best one until I was the parachute at last. It came down a long way away. wc
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#544
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The "standard" stomp rockets (2-liter bottle, 1/2" PVC piping and rocket bore, 10" or so long) will easily go 50 feet straight up or 75' down range (6-9 year old operators/stompers). Probably 100' vertical limit if Dad does some good, hard stomping.
If you use 1/2" CPVC (smaller outer diameter) and join two tubes to make an 18-20" rocket you can easily get 100' vertical and 150-200' downrange (smaller pipe gives a higher pressure and a longer rocket uses the pressure for a longer time = more power). If you build a reservoir/air tank (several on-line plans) and pump it up with a bicycle pump the performance should rival that of the smaller Estes rocket motors. NOTE: NASA pulled the plans for pumped-reservoir version earlier this year due to reported safety problems. Somebody must have exceeded the psi limits for the big PVC piping used for the reservoir - though the limit is clearly printed on the pipe itself. 4" schedule 80 is rated to 320psi while similar schedule 40 is limited to 110psi. You won't get to 320 with a bicycle pump, but you might be able to overstress the schedule 40, which is more common at the hardware store. You shouldn't lose them as the simple stomp rockets are light enough not to need a parachute - so don't drift too far. Don't ask me about trees, however. You can also up-rate the straw rocket launcher by picking up a replacement slingshot sling (rubber tubes and leather pad) at WalMart and using that instead of rubber bands to power the launcher. http://www.papermodelers.com/forum/d...do=file&id=224 Yogi Last edited by Retired_for_now; 10-18-2013 at 06:23 PM. |
#545
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The authority on high-performance hot-rodding of stomp rockets is mbauer (give him a PM for specifics). Relevant threads include
Flying Cardstock Rockets or How to Hot Rod Paper Rocket Models Saturn V Massive Build Many others as well. Use the forum search function for <stomp rocket>. Yogi |
#546
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More Falcon 9 v1.1
So far the bits seem to fit, though you could cobble one up from the existing kits (AXM or mine) by just printing off an extra first and second stage to cut down for the add-in plugs. Bottom is a little more challenging to make the (slight) conics but a simple cylinder would still be close with repositioned engines.
Grasshopper legs are tougher. Easy enough to add cosmetic, non-functional bits to the bottom - or just graphics. Actual parts involve a central channel for the extension ram and edge beams from the hinges to the tip that wrap diagonally around the first stage cylinder (don't really want to look up the geometry on that). So, may be a bit while I try and make a buildable set (inner skin, center channel, laminated edge beams, and outer skin) that actually fits together. So far, Yogi |
#547
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I've been trying to look for pictures of the thrust structure and legs mysef for a while now but I couldn't find anything remotely detailed yet. I can't really be bothered by all the stuff pointing further upward but that bottom section with the new configuration intrigues me. Especially these landing legs.
Looking forward to see what you make of it! |
#548
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P-K
For a small-scale at 1:200 you could just laminate the inner/outer skins and you'd get a pretty good to-scale thickness part. Ok, sorry. I know you don't do "pretty good." Problem remains the outer edge beams - they might look straight-ish in this perspective but they wrap diagonally around the cylinder so bend and twist. So far lamination looks like the best solution. Yogi |
#549
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So, still trying to figure out how to make a buildable set of Falcon landing legs (rest of the F9 v1.1 seems OK, could use some more greebles for camera housings, thrusters for control of the flyback booster, etc.). I think the shape is doable by laminating the edge beams around a mandrel - 1" PVC for choice.
But, need some research help. How many landing legs is Elon going to use? Grasshopper shows four, drawings are non-specific but seem to indicate 4. However. I initially drew up three because three is the minimum needed and I don't know why you'd put extra stuff/weight on a rocket. Anybody have the definitive answer? Yogi |
#550
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I would say four. More stable and as far as I can make up from the drawings, the most plausible. I still am looking into the leg as well, although I am a little busy filming.
The inner side of the V needs to be closed with a sloped part and I try to see how it fits into the construction. (the LM also had more than three legs. I guess because it is more stable than three...) Last edited by Paper Kosmonaut; 10-29-2013 at 02:55 PM. Reason: I added some wordt about the LM having four legs. Funny stuff, no? |
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