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  #1  
Old 03-24-2016, 10:47 PM
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blackshire blackshire is offline
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Default "E" motor-compatible pads?

Hello All,

I see that Estes' Porta Pad II is recommended for rockets up to "D" power (using a 3/16" diameter Maxi-Rod, of course), while they recommend their E-Launch pad (which can incorporate a 3/16" or 1/4" launch rod) and E-Launch controller for rockets using "E" and more powerful motors (up to the model rocket limit for "low G" impulse, I think). This raises a question:

The SpaceX Falcon 9 kit uses Estes D12-5 and E9-6 black powder motors. Could the Falcon 9 model, when powered by an E9-6 motor, be safely launched from the Porta Pad II (using a 3/16" Maxi-Rod), particularly if the Porta Pad II was weighted (or if its legs were tied to stakes in the ground)? Also:

The reason why I ask is because I had a SpaceX Falcon 9 kit and an older Manta II launch set (which came with a Porta Pad II) sent to a friend of mine, along with a 3/16" Maxi-Rod and some D12-5 motors for use with the Falcon 9 model (plus some 18 mm motors for the Manta II rocket). The E-Launch pad and E-Launch controller are rather expensive, but I think the Porta Pad II and the Electron Beam launch controller (whose 15' ignition leads are, I think, long enough to be safe with E9-6 motors) would work just fine for this and similar E9-6 applications. Many thanks in advance to anyone who can help!
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Old 03-24-2016, 11:04 PM
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Default NAR Safety Code

According to the NAR Safety Code, motors larger than D require a 30' safe distance. That would mean that using the Electron Beam would violate this policy.
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My Flight Statistics for the Past Year
  • Number of Flights: 31
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    - Total: 710.01 Ns (11% J)
    - Average: 22.90 Ns (15% E)
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  #3  
Old 03-24-2016, 11:34 PM
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Quote:
Originally Posted by chalinaty
According to the NAR Safety Code, motors larger than D require a 30' safe distance. That would mean that using the Electron Beam would violate this policy.
Thank you--while I knew that a "30' ignition leads rule" kicked in at some impulse level, I didn't know where the dividing line was. He's in France, so the NAR's rules may not apply (but the equivalent space modeling governing body there could very well have a similar rule, although even fuse ignition is rather common in European model rocketry...). But:

I can easily make up a set of 15' extension leads to go with his Electron Beam launch controller. (Both the Electron Beam controller and the E-Launch controller use four "AA" batteries, so the additional 15' of leads shouldn't cause any single-motor ignition problems, especially if I make the extension leads out of larger-gauge wire.) I don't think the Porta Pad II will be a problem with an E9-6 powered Falcon 9 model, as I've launched the large and heavy double D12-3 powered Cox Saturn V from a Maxi-Rod equipped Porta Pad several times, and the pad was steady.
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Old 03-25-2016, 08:33 AM
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I have launched models up to 16oz off a standard Estes Porta-Pad using the following engines over a D12.
E9, E12, E16, E18, E28, E30, F15, F24, F32, F39, F52 and even an old FSI F100.
I however would NOT reccommend launching anything over an E18 without staking the legs down and using a STIFF one-piece stainless 3/16" rod. Even then you get some serious rod-whip.
I use my Estes Porta Pad E's mostly now instead for even 1/8" rods with the right adapters.
I have launched MUCH higher impulse motors than full 80 n-sec F's off the Estes "E" porta pad.
I won't show the max I have flown off of it but suffice it to say it did NOT comply with current NAR high-power rules and was well over 160 n-sec total impulse and over 200 newtons average thrust but that was MANY years ago.
I also have a Saw-horse based home-brew 5-station "multi pad".
Using the E-pad for all G's except Warp-9 propellant should suffice.
I liked the old Estes original pro-series pad although it was way overpriced, just as the Aerotech Mantis is also. The Aerotech pad is actually kinda weak in certain areas.
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  #5  
Old 03-25-2016, 10:55 AM
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blackshire blackshire is offline
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Quote:
Originally Posted by ghrocketman
I have launched models up to 16oz off a standard Estes Porta-Pad using the following engines over a D12.
E9, E12, E16, E18, E28, E30, F15, F24, F32, F39, F52 and even an old FSI F100.
I however would NOT reccommend launching anything over an E18 without staking the legs down and using a STIFF one-piece stainless 3/16" rod. Even then you get some serious rod-whip.
I use my Estes Porta Pad E's mostly now instead for even 1/8" rods with the right adapters.
I have launched MUCH higher impulse motors than full 80 n-sec F's off the Estes "E" porta pad.
I won't show the max I have flown off of it but suffice it to say it did NOT comply with current NAR high-power rules and was well over 160 n-sec total impulse and over 200 newtons average thrust but that was MANY years ago.
I also have a Saw-horse based home-brew 5-station "multi pad".
Using the E-pad for all G's except Warp-9 propellant should suffice.
I liked the old Estes original pro-series pad although it was way overpriced, just as the Aerotech Mantis is also. The Aerotech pad is actually kinda weak in certain areas.
Thank you! I appreciate your posting this information, as I suspected that the launch pad recommendations were written with an "err on the side of caution" ('better safe than sorry') mindset, which I can't blame any model rocket manufacturer or hobbyist rocketry governing body for operating by. Due to the size of his flying field, at a nearby neighbor's small farm, E9-powered flights (or similarly-high flights with high-performance 18 mm models) are probably the limit at which he could still recover the rockets on the field (it's surrounded by woods), plus--due to common local cloud and wind conditions--E9 flights will be just occasional events for him. But the E9-6 in the Falcon 9 model does provide satisfyingly long-burning, high flights, particularly when the rocket carries a keychain video/still camera with sound to record the flights (see: www.youtube.com/watch?v=nY8Pe_w0mEs ), and even D12-5 powered flights with such a camera on a Falcon 9 are pretty impressive (see: www.youtube.com/watch?v=dgvIkyWRBEc ). Also:

Even though the NAR Safety Code says to use a launch controller with 30' ignition leads with "E" and higher impulse motors, I don't think a CATO with a low-end "E" motor such as the E9-6 would be dangerous if one was using a launch controller with 15' ignition leads. I launched my 1990s-vintage Estes Cox Saturn V (which used two D12-3 motors, the aggregate equivalent of an "E" motor) using my old Astron II 12 volt launch controller, which had 15' ignition leads (and I don't recall--although admittedly it's been a while--any mention of using longer ignition leads in the model's instructions). I wouldn't use 15' ignition leads with any motor more powerful than an E9, though. As well:

Point well-taken regarding using one-piece launch rods, and on staking the pad's legs for use with E18 and higher-impulse motors. (Long ago, Estes offered a third extension piece for their two-piece 1/8" launch rod [they may have recommended it for their 1/70th scale Saturn IB and/or 1/100th scale Saturn V kits], which gave the rod a total length of 53"--but that always seemed like it would have excessive whip!) I switched to even a 1/8" one-piece rod after rod-whip with a two-piece rod resulted in a few "corkscrew" and overly-weathercocked flights on breezy days; the one-piece rod cured the problem. (Had I flown anything heavier/more powerful than the Cox Saturn V, I would have gotten a one-piece 3/16" launch rod.) If he expresses interest in flying heavier rockets using higher-impulse "E" motors or anything more powerful, I'll recommend that he get a one-piece 3/16" rod at a hardware store the next time he visits the UK, which he does regularly (his local hardware stores in France might have only hard-metric size [5 mm, 6 mm, etc,] music wire rods). And:

I agree with you about the Mantis launch pad. I've seen one, and while it does work, it has a higher center of gravity than it needs to have, which makes longer support legs necessary, which in turn makes the whole pad bulkier and heavier than it could be. I never had one of Estes' Big Foot launch pads, but its four legs and very low center of gravity probably made it very stable even with long, heavy rockets on it. I believe it used "D" batteries that were housed in the pad base. An updated version could optionally also use those batteries as part of a relay launch system (used with another, self-contained hand-held launch controller powered by its own four "AA" batteries or a 9 volt battery), for igniting clustered motors *without* having to use a car battery.
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  #6  
Old 03-25-2016, 11:37 AM
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Quote:
Originally Posted by blackshire
Thank you--while I knew that a "30' ignition leads rule" kicked in at some impulse level, I didn't know where the dividing line was. He's in France, so the NAR's rules may not apply (but the equivalent space modeling governing body there could very well have a similar rule, although even fuse ignition is rather common in European model rocketry...). But:

I can easily make up a set of 15' extension leads to go with his Electron Beam launch controller. (Both the Electron Beam controller and the E-Launch controller use four "AA" batteries, so the additional 15' of leads shouldn't cause any single-motor ignition problems, especially if I make the extension leads out of larger-gauge wire.) I don't think the Porta Pad II will be a problem with an E9-6 powered Falcon 9 model, as I've launched the large and heavy double D12-3 powered Cox Saturn V from a Maxi-Rod equipped Porta Pad several times, and the pad was steady.


Yes, it can be done... as you said, weight down the legs or pin them to the ground with spikes or long coat hangers or something bent into a "U" shape and pushed deeply into the ground, preferably at an angle, to pin the legs down (I prefer weight myself if I were doing that). Better yet build your own pad using wood and a tin can cut in half and turned inside out for a blast deflector, like my "Pad 34-Z ("Z" for "Zooch") which looks MUCH better and more realistic (ups the "cool" factor, plus the additional weight of a 2x12 base two feet long provides enormous stability for anything powered by "model rocket engines" (it would need to be bigger for HPR, but that's beside the point-- I'm not interested in HPR).

IMHO their "recommendations" are aimed mostly at selling additional expensive pad and launch control gear. The "E" controller is a rather shabby controller IMHO-- it still uses the dinky bell wire (just more of it for longer leads) and the crummy "AA" batteries to provide power... I rebuilt all my Estes controllers (which are all at least 30 years old... an old "Electron Beam" back when you had to assemble them yourself, from my first starter set, and a "Pola-Pulse" that used the old flat Polaroid batteries (which were just as lousy as AA's IMHO, and much more difficult to find and more expensive to boot). I soldered in lamp cord from the dollar store and a pair of battery charger clamps to connect it to a car battery (raise the hood) or better yet a car battery jumper pack (much more portable). Unlimited launch power for anything you want to fly then. I also replaced the stupid dinky bell wire with lamp cord from the dollar store and soldered on some copper microclips I bought at Radio Shack years ago. This reduces the resistance considerably. I have since installed regular 110 volt "replacement plugs" on the lead-out from the controller about a foot down the wire-- this makes the controller more compact to store in the range box, and allows a regular 25 foot extension cord to be used for the launch leads. The microclips are still on lamp cord about 5 feet long, equipped with a plug to plug into the extension cord. I also dumped the stupid flashlight bulbs they originally came with for continuity, and replaced them with LED's equipped with current limiting resistors, one that burns whenever the battery is hooked up with a good connection, and the other lights when the key is inserted. I also made my own keys using solid Romex house wire... cut a piece about 2-3 inches long, strip the insulation off it, straighten it out, and curl one end around into a "loop" using a pair of pliers, and solder the loop closed... instant launch key and it gets MUCH better contact with less resistance than steel launch keys the controllers come with, which are prone to corrosion as well.

Of course this is all probably a lot more trouble than you want to go to... If you don't want to modify the controllers but still get the extra distance "required" for E motor setbacks, simply get a roll of lamp cord from the local "Dollar Store" (which can be had for about a buck or two) and solder on a pair of micro-clips to connect to the ignitor. Simply clip the existing controller microclips onto the extension wires (strip them back about a half-inch and twist the wires... make sure the clips don't touch of course and cause a short circuit...) Then simply use the existing AA powered launch controller as normal... It'll be every bit as good as the expensive "E" controller... To ensure that the leads don't touch and short out, a piece of large "heat shrink tubing" can simply be slid over one clip once the extension is hooked up to provide a barrier between the two... or a piece of tape applied over one clip to isolate it from the other...

Later and good luck! OL J R
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Old 03-25-2016, 11:46 AM
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Quote:
Originally Posted by ghrocketman
I have launched models up to 16oz off a standard Estes Porta-Pad using the following engines over a D12.
E9, E12, E16, E18, E28, E30, F15, F24, F32, F39, F52 and even an old FSI F100.
I however would NOT reccommend launching anything over an E18 without staking the legs down and using a STIFF one-piece stainless 3/16" rod. Even then you get some serious rod-whip.
I use my Estes Porta Pad E's mostly now instead for even 1/8" rods with the right adapters.
I have launched MUCH higher impulse motors than full 80 n-sec F's off the Estes "E" porta pad.
I won't show the max I have flown off of it but suffice it to say it did NOT comply with current NAR high-power rules and was well over 160 n-sec total impulse and over 200 newtons average thrust but that was MANY years ago.
I also have a Saw-horse based home-brew 5-station "multi pad".
Using the E-pad for all G's except Warp-9 propellant should suffice.
I liked the old Estes original pro-series pad although it was way overpriced, just as the Aerotech Mantis is also. The Aerotech pad is actually kinda weak in certain areas.


The Mantis can be a DISASTER...

At a launch out here a few years ago, one of the club members used his Mantis pad to launch a large model rocket with a G motor... the rocket chuffed a few times and kicked the pad around, then finally ignited and came up to pressure-- just as the "lean over" feature of the Mantis turned loose and the rod tipped over toward horizontal... the rocket took off at about a 45 degree angle and blew the pad completely over... we all "puckered up" and held our breath as this rocket roared completely over the farm and over the neighboring place, apparently headed directly towards impacting a mobile home next door. Thankfully it went "long" and impacted in the drainage ditch behind their place...

If you're going to use a Mantis for big motors, I highly recommend you inspect the "lean over" feature and make sure that everything is tight and can stand up to the force of launch...

Later! OL J R
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Old 03-25-2016, 01:17 PM
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Quote:
Originally Posted by luke strawwalker
Yes, it can be done... as you said, weight down the legs or pin them to the ground with spikes or long coat hangers or something bent into a "U" shape and pushed deeply into the ground, preferably at an angle, to pin the legs down (I prefer weight myself if I were doing that)...[SNIPPED only for brevity]...Of course this is all probably a lot more trouble than you want to go to... If you don't want to modify the controllers but still get the extra distance "required" for E motor setbacks, simply get a roll of lamp cord from the local "Dollar Store" (which can be had for about a buck or two) and solder on a pair of micro-clips to connect to the ignitor.
As a mentor of your cinematographic namesake famously said, "Your insight serves you well." :-) Tiring more quickly these days, I go for the SIB ("Simplest Is Best") solutions to such problems. A 15' length of dual-conductor lamp cord (equipped with micro-clips on the launch pad end, and solder-"tinned" bare leads on the other) will work nicely. Using a large, two-screw terminal connector block (which I have) might be even better than using tinned leads, because the Electron Beam controller's micro-clips could be connected to the terminal block's "flange-insulated" flat pigtail leads without accidentally shorting anything.
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Old 03-25-2016, 11:41 PM
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I don't know if you are old enough to remember how loud a real M-80/ Silver Salute/Cherry Bomb is or how loud the 'bootleg' ones prior to 9/11 were (now very hard to find due to the ridiculous explosive regs now, but that's a whole other ridiculous subject) or how loud a Peacock Cracker Bomb is (legal if you have the proper pyrotechnic permits still), but a max cato of an E9 can be as loud and you can feel a concussive shock wave even from 30 feet away.
An 'old school' FSI F100 max cato can be almost but not quite as loud/forceful as a "Quarter Stick" or "Block Buster" which is fairly serious.
Do I bother with 30' leads with E9's ?
Nah, and don't with anything under a G64 either.
I fly on private land, usually alone or with one other person and a dog....lol.
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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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  #10  
Old 03-26-2016, 12:51 AM
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Quote:
Originally Posted by ghrocketman
I don't know if you are old enough to remember how loud a real M-80/ Silver Salute/Cherry Bomb is or how loud the 'bootleg' ones prior to 9/11 were (now very hard to find due to the ridiculous explosive regs now, but that's a whole other ridiculous subject) or how loud a Peacock Cracker Bomb is (legal if you have the proper pyrotechnic permits still), but a max cato of an E9 can be as loud and you can feel a concussive shock wave even from 30 feet away.
An 'old school' FSI F100 max cato can be almost but not quite as loud/forceful as a "Quarter Stick" or "Block Buster" which is fairly serious.
Do I bother with 30' leads with E9's ?
Nah, and don't with anything under a G64 either.
I fly on private land, usually alone or with one other person and a dog....lol.
We made a few craters in our front yard in Miami with those (and there are still chips of granite shrapnel from a cherry bomb embedded in the walls in the garage there...). I'll make up a set of 15' extension leads for use with an Electron Beam for igniting E9-6s (I might take a slight risk with myself, but not with someone else).
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