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Hello 3J's Dad,
Personally, I'd avoid rotary switches. I and many others have seen too many unexpected surges and accidental ignitions while rotating that switch between pads which is not a good thing. Rotary switches were great technology back in the 1950's but we've come a long ways since them. Current tech rotary switches are probably better but I wouldn't know. Its just that all the home-built systems I've seen over the years with rotary switches were prone to surge problems.
Mark N's 4-H paper is quite good for a single pad system, but I prefer to put the switches on the POSITIVE side of the power lines before you get to the FIRE switch and the continuity circuit. This change also allows for this design to much more easily become a multi-pad system design. But his design is only a single pad system and you want more than that. If you want to build a system, like this with multi-pad capability, look at the PDF design I've attached. Its slightly modified from many sources over the years but is basically the design I built in the late 1980's. The original I built was for 12 pads but I have no idea what it would cost to build this system today as I've gone a slightly different direction with the launch systems that I build these days.
John Hruby's system is also workable. But the $215 price tag is just for parts and does NOT include your labor which will be considerable. And the price tag John shows is just a 4-pad system. That's $53.75 per pad just for parts. Extrapolating for a 6-pad system with this design will cost you roughly $300 which I would guess is well outside your budget. If you're going to spend that kind of money and then have to build it, your better off to purchase a system.
The commercial systems for what you're looking of which others have spoken are:
Art Applewhite's FORTE 4-pad system costs $150 which is $37.50 per pad.
Rocket Works Houston - 6-pad system costs $224.99 which is $37.50 per pad
Pratt Hobbies SIXPACK - 6-pad system costs $149.95 which is $24.99 per pad
I've never seen or talked with anyone who uses either Art Applewhite's "FORTE" or Rocket Works "Houston 6" so I really don't have any way to judge their user-friendliness and durability. What's on their websites looks good as far as it goes, but I'm looking for end-user evaluations not advertising. Can anybody tell us about either or both of these systems?
The Pratt Hobbies SIXPACK launch system has been around for a long time and has a very good track record for longevity and ease of use from many folks over the years. Does anybody know if he's still in business? I'm sorry, but I really don't know. For your money's worth, if he is this is the way I'd go if I were you. His system will work out of the box and you won't have to worry about whether or not you built it right. And it will cost half of what building John Hruby's system will cost which is just for the parts and only controls four pads.
I have a long term interest in rocket launch systems going back as far as the late 1960's. I built my first single pad system in 1967 from all scrounged parts except the alligator clips and the battery. I built my first 8-pad system in 1968. It was primitive, had no continuity check, and the system on/off key switch was scrounged from a scrapped riding lawn mower as was the 12v battery that could only charge to 9 volts. The pad select switches were a mixture or different sized scrounged toggles, and the fire keys were doorbell switches from the hardware store down the block. And all the wiring was scrounged from the wiring harness out of a crashed/mangled FORD Galaxy in the junk yard.
I currently have a rather more professional interest and curiosity with club sized launch systems as I am the owner of Wilson F/X Digital Launch Control Systems and I've traveled across the USA starting in 1991, looking at dozens and dozens of club launch systems for ideas of how and how not to build things. But launch systems like many things in life are an economy of scale which is why most of my business is with clubs who are expecting and hoping to grow over the years. The Pratt Hobbies, Art Applewhite, and Rocket Works systems mentioned above are good for what you get, but they can't grow larger. However, a Wilson F/X launch system is designed for larger organizations and heavy long term use which would be a serious overkill for what you're looking.
Good luck and let me know if you have any questions.
Brad, the "Rocket Rev.," Wilson
Personally, I'd avoid rotary switches. I and many others have seen too many unexpected surges and accidental ignitions while rotating that switch between pads which is not a good thing. Rotary switches were great technology back in the 1950's but we've come a long ways since them. Current tech rotary switches are probably better but I wouldn't know. Its just that all the home-built systems I've seen over the years with rotary switches were prone to surge problems.
Mark N's 4-H paper is quite good for a single pad system, but I prefer to put the switches on the POSITIVE side of the power lines before you get to the FIRE switch and the continuity circuit. This change also allows for this design to much more easily become a multi-pad system design. But his design is only a single pad system and you want more than that. If you want to build a system, like this with multi-pad capability, look at the PDF design I've attached. Its slightly modified from many sources over the years but is basically the design I built in the late 1980's. The original I built was for 12 pads but I have no idea what it would cost to build this system today as I've gone a slightly different direction with the launch systems that I build these days.
John Hruby's system is also workable. But the $215 price tag is just for parts and does NOT include your labor which will be considerable. And the price tag John shows is just a 4-pad system. That's $53.75 per pad just for parts. Extrapolating for a 6-pad system with this design will cost you roughly $300 which I would guess is well outside your budget. If you're going to spend that kind of money and then have to build it, your better off to purchase a system.
The commercial systems for what you're looking of which others have spoken are:
Art Applewhite's FORTE 4-pad system costs $150 which is $37.50 per pad.
Rocket Works Houston - 6-pad system costs $224.99 which is $37.50 per pad
Pratt Hobbies SIXPACK - 6-pad system costs $149.95 which is $24.99 per pad
I've never seen or talked with anyone who uses either Art Applewhite's "FORTE" or Rocket Works "Houston 6" so I really don't have any way to judge their user-friendliness and durability. What's on their websites looks good as far as it goes, but I'm looking for end-user evaluations not advertising. Can anybody tell us about either or both of these systems?
The Pratt Hobbies SIXPACK launch system has been around for a long time and has a very good track record for longevity and ease of use from many folks over the years. Does anybody know if he's still in business? I'm sorry, but I really don't know. For your money's worth, if he is this is the way I'd go if I were you. His system will work out of the box and you won't have to worry about whether or not you built it right. And it will cost half of what building John Hruby's system will cost which is just for the parts and only controls four pads.
I have a long term interest in rocket launch systems going back as far as the late 1960's. I built my first single pad system in 1967 from all scrounged parts except the alligator clips and the battery. I built my first 8-pad system in 1968. It was primitive, had no continuity check, and the system on/off key switch was scrounged from a scrapped riding lawn mower as was the 12v battery that could only charge to 9 volts. The pad select switches were a mixture or different sized scrounged toggles, and the fire keys were doorbell switches from the hardware store down the block. And all the wiring was scrounged from the wiring harness out of a crashed/mangled FORD Galaxy in the junk yard.
I currently have a rather more professional interest and curiosity with club sized launch systems as I am the owner of Wilson F/X Digital Launch Control Systems and I've traveled across the USA starting in 1991, looking at dozens and dozens of club launch systems for ideas of how and how not to build things. But launch systems like many things in life are an economy of scale which is why most of my business is with clubs who are expecting and hoping to grow over the years. The Pratt Hobbies, Art Applewhite, and Rocket Works systems mentioned above are good for what you get, but they can't grow larger. However, a Wilson F/X launch system is designed for larger organizations and heavy long term use which would be a serious overkill for what you're looking.
Good luck and let me know if you have any questions.
Brad, the "Rocket Rev.," Wilson
