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Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
Haven't really done much with HV for the past few years. Here is one of my newer hobbies. This particular project is a 3/4 scale Nike Smoke rocket. The Nike Smoke rockets were used during the Apollo missions, launched prior to the Apollo flights, to get an idea of what the upper atmosphere winds were doing. The Nike Smoke would literally create a smoke trail (hence its name) so wind currents could be seen and analyzed.
This particular rocket is being designed to fly on a cluster of (4) M impulse motors for a combined "O" motor impulse. Expected to break Mach 1 and reach an altitude of almost 20,000 feet. Total weight of the rocket at launch (loaded) will be between 150 and 200 lbs.
So far, as shown in the photos above, i've been working on the fin section and internal bulkheads for the booster section. Each of those motor tubes holds a 75mm motor which is about 4 feet in length.
Registered Member #690
Joined: Tue May 08 2007, 03:47AM
Location: New Jersey, USA
Posts: 616
So will it have a separate "smoke charge" to ignite once it's near its peak altitude, or does it just use the smoke from the motors? Either way, will you actually be measuring the wind speeds in the upper atmosphere?
The largest motor I've ever even seen is a D, and I've only ever used As when I was like 11. I didn't know that exponential lettering system went up so far!
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
What motors specifically are you planning to use? With a 200lb rocket (I still don't see how you could need 200lbs to make 15ft tall rocket, but whatever works) it isn't that huge of an issue but if you load 4x M2000R's you are talking 10g's which might be pushing it for that airframe (even if 75-100lbs of that is motor down at the bottom). That 50lbs of nose weight is going to feel like 500lbs trying to crumple your airframe...
The craftsmanship looks excellent otherwise, just like the rest of the work you do. Working with birch after using Plexiglas must be really rewarding
When are you planning to fly it? I might have a rev 4 of my gps tracker ready for testing...
BTW, I am pretty sure that Dan doesn't plan to actually use this rocket for sounding... The bit about smoke was just historical. This one does however make a nice smoke trail while the engines are burning
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
... wrote ...
What motors specifically are you planning to use? With a 200lb rocket (I still don't see how you could need 200lbs to make 15ft tall rocket, but whatever works) it isn't that huge of an issue but if you load 4x M2000R's you are talking 10g's which might be pushing it for that airframe (even if 75-100lbs of that is motor down at the bottom). That 50lbs of nose weight is going to feel like 500lbs trying to crumple your airframe...
The craftsmanship looks excellent otherwise, just like the rest of the work you do. Working with birch after using Plexiglas must be really rewarding
When are you planning to fly it? I might have a rev 4 of my gps tracker ready for testing...
BTW, I am pretty sure that Dan doesn't plan to actually use this rocket for sounding... The bit about smoke was just historical. This one does however make a nice smoke trail while the engines are burning
The airframe is fiberglassed considerably for the stresses and all the bulkheads and other support structures are made from 3/4" aircraft plywood so the weight adds up pretty quickly. Actual weight will likely be about 150 lbs loaded.
Test flight will be on (4) M650Ws i believe which is a pretty benign flight, but final flight will be on some EX motors with plenty of kick.
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
The rocket club I belonged to back in the day all made "small" rockets. Now most all of those guys are making this big stuff. I admire the hell out of the team work & final product but don't you have to contact the FAA and do all sorts of red-tape BS if you live even close to any airfield or the trajectory is over 10k feet within approach to same, bla, bla, bla?????
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
quicksilver wrote ...
The rocket club I belonged to back in the day all made "small" rockets. Now most all of those guys are making this big stuff. I admire the hell out of the team work & final product but don't you have to contact the FAA and do all sorts of red-tape BS if you live even close to any airfield or the trajectory is over 10k feet within approach to same, bla, bla, bla?????
No not at all - BS that is.
There are clubs in the area (in particular NY Metro and MDRA in Maryland) that do all that stuff for you. You just show up to the launch. FAA clearances and NOTAMs are already worked out and typically good up to about 15-16k feet depending on the launch site.
Even if you did it on your own, its not really a big deal. You just fill out a form and submit to the FAA and they grant you the clearance (for the particular area). For HPR flights in our area (urban Philadelphia), its usually about 3k feet clearance.
And the FAA must grant your request. Everyone has the right to use an airspace assuming its available and not already being used (i.r. military, commercial airports, etc...)
BTW, our local club, uses a field 1/4 mile from a local airport. FAA grants the request to 3000k and issues a NOTAM for that day to all surrouding airports telling aircraft to avoid that area from the specified times.
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042
just make sure that your motor timings are not even slightly off... it is a VERY bad situation, but it was different than I expected (in case this never happened to you): it goes off, with say one motor igniting later, so it goes off course, but once all the motors are in near sync in their thrust output, it flies strait like normal, then off again when the other engines die before the last one goes out... had an issue with this a while back, don't let that happen to you...
also, who are you getting the motors from? some companies, at least that I have seen, design some of their engines for cases like these where smoke is wanted.
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
DaJJHman wrote ...
just make sure that your motor timings are not even slightly off... it is a VERY bad situation, but it was different than I expected (in case this never happened to you): it goes off, with say one motor igniting later, so it goes off course, but once all the motors are in near sync in their thrust output, it flies strait like normal, then off again when the other engines die before the last one goes out... had an issue with this a while back, don't let that happen to you...
also, who are you getting the motors from? some companies, at least that I have seen, design some of their engines for cases like these where smoke is wanted.
Yes. Simulataneous firing of the clusters is a must, especially in this configuration. (Typically, there is a larger central motor which provides enough thrust to safely lift rocket in the event the outboards don't light properly)
Magnesium based thermite is being used to ignite the motors.
The first test runs will utilize commercial motors (about $3200 for the flight when you factor in the price of (4) 75mm aerotech reloadable cases) Subsequent flights will be on EX motors i'm designing and building myself which includes cases as well.
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