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  #1  
Old 10-14-2006, 07:55 AM
bikegod bikegod is offline
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Join Date: Mar 2006
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Default RMS questions (again)

After waiting for what seems like forever for a 24mm engine, I ended up with an 18mm housing as well. I of course ordered 1 set of charges for it and being as it was an unexpected boon, decided to practice loading on it instead of my 24.

Maybe I am dense, but the instructions didnt' seem quite clear to me. I expected the load to just slip in. I also didn't realize that the ejection charge was in the little red caps that came with it. I spilled it all over my workbench but was able to scoop it all back in.

Lastly, the copperhead igniter, looks like one piece of metal. Where do I connect two leads to it to cause the igniter to ignite?

I had never intended to get the 18mm, and I still haven't loaded the 24. I am quite afraid of igniting this thing for fear of an unexpected explosion. Mostly because I really had to convince that charge to slip in. Once I had it part of the way I couldn't pull it out so I forged on ahead. None of the charges in the 3-pak fit any better. Some of the cardboard sleeve got distended and I ended up trimming it off.

Before I load up the 24, can anyone chime in on their (recent) experiences with the 18? Could I possibly have a bad casing or loads?

Bike
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  #2  
Old 10-14-2006, 10:29 PM
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ghrocketman ghrocketman is offline
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One often has to "coax" the propellant grains into ANY/ALL of the RMS cases, be it hobby line (18/20, 24/40, and 29/40-120) or the various 29-38-54-75-98mm HPR RMS cases. Often one has to peel part of the cardboard liner off the propellant grain to get it into the case. You are NOT experiencing anything abnormal.
Many new RMS users expect it to be a "Wham-Bam & you are done" experience in building RMS loads. It sometimes can be, but it is usually NOT so.
Some use a thin layer of "O-ring" grease on the outside liner of the propellant grain to get it into the casing also.
The key to RMS is in taking your time and following the directions EXACTLY.
If you don't follow the directions exactly the result is often a CATO !
When using copperheads, the easiest way is to use the special Aerotech "interlock" igniter clip, which is designed for them. The copperhead actually has two leads that are separated by a fine layer of plastic. It is a copper-plastic-copper sandwich. I use a lighter on the non-pyrogen coated end to melt the plastic....the two halves of copper curl away from each other...then one can use regular micro-clips.
When using copperheads (or ANY igniters for composite-propellant engines) you ABSOLUTELY CANNOT use a 4AA cell Estes-type "Electron Beam" controller to fire them....it WILL NOT RELIABLY WORK !
You MUST use a 12V car-battery power source type controller such as the Aerotech Interlock controller or the old Estes ASTRON launch controller. I personally have both & use both. One can also build their own 12V controller if they have the electrical experience.
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  #3  
Old 10-14-2006, 11:05 PM
bikegod bikegod is offline
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Thanks, I knew someone out there would alleviate my fears.

The 18 seems jammed in there, but the 24mm with E11s went just fine. In fact I almost forgot to grease it as I was test fitting the parts it just started to go together. Before I got to the ejection charge though I went back and lubed it up in just the right places.

Concerning the 18 though, I lubed up the case, the charge and o-rings etc. I still am not sure what I plan on sacrificing to it (all of my 18mm rockets may be way overpowered by th D-13 loads).

Concerning the ingition: Cigarette lighter adapter and say 25' or more of lead to microclips. What do you think? My ignition would be plugging it into the lighter socket, with the failsafe of the car must be turned on for the lighter to have power. I have three sockets in my PT and two are keyed (won't come on without being in at least accessory postition).

Tomorrow (if I can get my electronics together) may see the maiden flight of my SLS-Laser. I am only planning an E-18 for first flight. Based on RockSim, I should see about 1000' (though with the amount of paint and filler I have on it, I am only hopeful of the first 5 or 6 hundred). I really considered an E11, but my RockSim doesn't have that engine on file and I haven't been able to get the Engine Edit to work right for me yet. I used an E-12jrc for the numbers but don't trust them.

Sorry to be so chatty about RMSs and the like, but SLS models and RMS engines are so new to me. I first, don't want to kill/hurt/ or otherwise ruin anyone's day, and second, don't want to blow up my beautiful rocket (which, by the way, has probably 40 hours worth of sanding/refinishing on it). Not bragging, but I have never spent this much time or care on anything so far. It has been quite rewarding and I hopefully have learned some patience and how not to depend on shortcuts.

I plan on getting some decent photo's of it before I light it up. I am quite proud of my fillets (thanks to SkyPirate's instructional) and the finishing details (thanks to all of you here) and last but not least thanks to Carl@Semroc for the awesome kit in the first place. If she my first RMS experience, I may ask for the 29mm engine mount (I glued in the 24mm adapter) and try some larger engines and loads.

Wish me luck tomorrow. Sunny and 61 here, ist the forecast for Sunday. As long as the breeze isn't too high, you may see my launch report here as well.
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  #4  
Old 10-14-2006, 11:35 PM
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CPMcGraw CPMcGraw is offline
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Quote:
Originally Posted by bikegod
...Concerning the ingition: Cigarette lighter adapter and say 25' or more of lead to microclips. What do you think? My ignition would be plugging it into the lighter socket, with the failsafe of the car must be turned on for the lighter to have power. I have three sockets in my PT and two are keyed (won't come on without being in at least accessory postition).


If you can find one of the earlier BLUE-PLASTIC Electron Beam controllers, these were assembled with screws instead of being heat-welded together. You can add an extra set of wires connecting to the internal battery terminals that run to either that cig port plug, OR get some heavier-duty gater-grabbers and some 14-gauge zip chord, and have all the convienience of a regular controller with the oomph of a 12V car battery instead of the 6V from four AA's. Just swap out the 6V bulb with a 12V bulb, and you're set. Swap out the remaining 20' of lead wire with more 14-gauge zip chord and you should be able to handle up to three-motor clusters without a Chernobyl...
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  #5  
Old 10-14-2006, 11:47 PM
bikegod bikegod is offline
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I actually have one of the Blue Ebeam controllers. I got it with an old kit from Wally World years ago (sat in my closet till this year and pulled it out when I was off my feet, and soon became Born Again).

I thought it was defective when the light wouldn't come on. I emailed estes and they sent me the yellow controller (still in the package to this day). While fooling with the blue one, I connected an igniter to it with 4AAs and tested it. Of course it worked, and I ended up with two controllers.

I'll hit Radio Shack tomorrow and get my supplies. Now I won't need micro clips! Hate soldering anyhow. BTW, would two 9Vs work (if I can't get my car close enough to the field)? Or what about a garden tractor battery? I think they are 12V also (but I am not sure).

Thanks for the idea. Even though it is almost 1 here, I am going to pull my controller out and check it out now!

Later: Color me bummed, but the original Ebeam controller I have is black and welded shut, however, the new yellow one has two little screws in the bottom of it. The launch key seems to be MIA, but it looked the same as the other one that is still attached to the black controller. What a deal!

My original kit (Code red, 3 engines, pad and controller) set my Father in Law back almost $15 3-4 years ago. Who would've thunk I'd be doing this now.

I kick myself for letting it sit in the closet for so long.
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  #6  
Old 10-15-2006, 12:03 AM
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CPMcGraw CPMcGraw is offline
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Quote:
Originally Posted by bikegod
Later: Color me bummed, but the original Ebeam controller I have is black and welded shut, however, the new yellow one has two little screws in the bottom of it. The launch key seems to be MIA, but it looked the same as the other one that is still attached to the black controller. What a deal!


I have a black controller with screws...

Most of the late-model controllers are heat-welded, but mine is several years old and came with an Astrocam 110 Starter Set.

The oldest launch keys from the Solar Controller would work, too...
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  #7  
Old 10-15-2006, 09:37 AM
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ghrocketman ghrocketman is offline
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A garden tractor battery would be fine !
2 9V batteries would not...they do NOT have the amperage (current) needed to reliably fire Copperheads.
Do not try the cigarette lighter trick in the car....this car circuit does not have enough amperage either (you will probably blow a fuse in the car)....how do I know this one ?
I'm an Electrical engineer for one of the big auto companies up in Michigan.

I personally use a 12V motorcycle battery to launch my Aerotech engines with Copperheads and for up to 4 engine Estes clusters. Works great, has plenty of current and capacity, and does not break your back carrying it to the launch site.

One word of advice....save the "J (blackjack) propellant type" Aerotech loads for lighter rockets....that is the lowest average thrust propellant Aerotech offers.

In general, for order of average thrust/burn rate from high to low this is the Aerotech propellant chart:

1) Warp9 "N propellant" fastest burning/highest avg. thrust
2) Blue Thunder "T propellant"
3) Red Line "R propellant"
4) "fast" White Lightning "W propellant"
5) Black Max (Fast Jack) "FJ propellant"
6) "standard" White Lighting "W propellant"
7) Black Jack "J propellant" slowest burning/lowest avg. thrust.

Note 1: Aerotech does not officialy denote between "Fast" and "standard" White Lightning.

Note 2: Not all of the above propellants are offered in the "Hobby line"/ non high-power RMS cases. Only Blue Thunder, "standard" White Lightning, and Black Jack are offered in the hobby line cases.

Note 3: one does not have to be HPR certified to use the following HPR cases: 29/60, 29/100, 29/120. Redline propellant is offered in a load for the 29-100 case in the form of the G77-R.

Note 4: The hobby-line RMS 29/40-120 load of G33J technically requires HPR certification to fly it due to total propellant mass being over 62.5 grams. This is due to our "friends" at the Gestapo...oops I mean BATFE.



The E18W should be fine in your SLS Laser X, but for a first flight I think I'd use the RMS 24 D15-4T instead....It will only get to 300' or so but it would give you an idea of the flight profile of the Laser. 1000' is kind of high for a first flight even in a rocket this large. I personally used the RMS24 D15-4T for the first flight of my Semroc SLS Hustler, which is bigger and draggier than the SLS Laser. It flew to about 300' and recovered fine. Also used that engine for my Enerjet Athena and '72 Enerjet Aero Dart clones for the maiden flight. It was a good choice.
__________________
When in doubt, WHACK the GAS and NEVER touch the brake !!!
No Harm=NO Foul advocate
BE a MENACE; CREATE the HAVOC, CHAOS, and MAYHEM
Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
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  #8  
Old 10-15-2006, 01:02 PM
bikegod bikegod is offline
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Concerning the Cig adapter: Don't the copperheads need only 3 amps to ignite? The adapter that I just got today is rated at 5 amps, and the outlet is fused at 10 amps. I respect your knowledge of electrical engineering, I am just trying to understand.

I more than likely will go with the garden tractor battery (14.97 at walmart vs. the 51 for motorcycle batteries). BTW, how many launches do you think I could get (single engine aerotech) off of two lantern batteries?
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  #9  
Old 10-15-2006, 01:12 PM
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CPMcGraw CPMcGraw is offline
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Quote:
Originally Posted by bikegod
Concerning the Cig adapter: Don't the copperheads need only 3 amps to ignite? The adapter that I just got today is rated at 5 amps, and the outlet is fused at 10 amps. I respect your knowledge of electrical engineering, I am just trying to understand.

I more than likely will go with the garden tractor battery (14.97 at walmart vs. the 51 for motorcycle batteries). BTW, how many launches do you think I could get (single engine aerotech) off of two lantern batteries?


One additional possibility, and this comes from my "other hobby" experience...

Have you thought about getting one of those RC aircraft field boxes with the battery compartment? Put a rechargeable "gel-cell" battery in there for power. Use the drawers for goodies like extra igniters, knives, blades, glue, etc...

With a little extra plywood and some work, you can re-fit the fuel bottle area with other holders or drawers, maybe a place to hold the launch controller...

...Or even add a launch rod and a blast deflector, and you've got a "modern" Powr-Pad...

Never ignore the other areas of your LHS. They're a gold mine of possibilities...
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  #10  
Old 10-15-2006, 01:31 PM
bikegod bikegod is offline
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Ihave been using a small box for parts, but as the fleet has grown, I have been trying to figure out how to safely transport them to the field.

What does LHS mean? I am sure that I am just being dense.

Oh, and do you think I might get a launch or two from the Lantern batteries? At least until I get the extra tractor battery or buy the motorcyle battery (which, being smaller is way more attractive when I have to hike out 300 yards from the parking lot of my big field).
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