Launch pad design.

Discussion in 'Ground Support' started by FlyingMonkey, Nov 27, 2019.

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  1. Nov 27, 2019 #1

    FlyingMonkey

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    I'm surprised by the lack of build info/pics I've been able to find.
    Even in person I get "I dunno I bought it from some guy" or "the guy who used to machine these parts has passed".

    I'm looking to build a setup for maybe 4 rods 1/8 and 3/16. I was looking for azimuth and tilt but I suppose a sawhorse (the likely stand) can easily be turned. So just a tilt adjustment should do. One suggestion was to use an adjustable flag pole bracket but I'd love to hear or see some other ideas.
     

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  2. Nov 27, 2019 #2

    rharshberger

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    Or this....all parts are easily made using a drill press, and a few taps and someone with a welder. The type of adjustment/head is known as a Spadpad after the late Bill Spadfora. The pads were not expensive to build and any single part is easily replaceable, the top piece where the rods mount are drilled for 1/8" (five of them) one drilled with both 1/8 and 3/16.
     

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  3. Nov 27, 2019 #3

    FlyingMonkey

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    Ah, there we go! Having a name sure helps with search criteria. I could definitely build something like that.
     
  4. Dec 3, 2019 #4

    RFMan

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    When I did a 12-pad launcher for 4-H, I rotated (tilted) the entire top 2x4 that had fixed blast deflectors and rods. One end was attached to a 3" lazy Susan turntable bearing. The other side had a home-made U-bracket made from strap iron, which fastened to the support member with a large bolt, some washers, and a wing nut. Loosen the wing nut, tilt 2x4, tighten nut - no tools required.

    Maybe I can dig up a picture or two.
     
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  5. Dec 3, 2019 #5

    FlyingMonkey

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    The club LP pads seem to be pretty close to each other. What distance should be the minimum? I'm trying to decide how many I can realistically fit onto my saw horse. Club has 5 but seems sawhorse size isnt universal. Screenshot_20191203-103130_QuickPic.jpg
     
  6. Dec 3, 2019 #6

    rharshberger

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    iirc the pads I built are 12" center to center.
     
  7. Dec 3, 2019 #7

    FlyingMonkey

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    Another question would be in regards to deflector size. I have an estes LP launch pad to reference for minimum LPR sizing (my plates will be a touch thicker) but what about mid power?
    I'm just now getting into F-G and G is the largest allowed at this site.
     
  8. Dec 3, 2019 #8

    Wallace

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    I'd reccomend deciding on worst case use and at the very least, doubling it. Not a good place to scrimp.
     
    Last edited: Dec 3, 2019
  9. Dec 3, 2019 #9

    FlyingMonkey

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    I won't be ready for launch for a bit so maybe next event I'll just drive out there and take measurements.
     
  10. Dec 3, 2019 #10

    cwbullet

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    Sir,

    Can you post or send me a parts list for the heads? I really like that design.
     
  11. Dec 3, 2019 #11

    Wallace

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    And I can tell you that a 29mm motor will blow a nice round hole in 16 gauge copper from 6 inches or so...
     
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  12. Dec 3, 2019 #12

    rharshberger

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    No problem, be forewarned that its ALL steel and each 6 pad unit is heavy but very stable.
     
  13. Dec 3, 2019 #13

    rharshberger

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    We generally use 4" metal electrical box covers for blast deflectors on the LPR pads, for MPR rods its 6"×.125" pipe blinds (round flat disc welded to the end od steel pipe to close it off. We drill a 1/4"-ish hole to allow them to fit LPR and MPR as needed. Standoffs are small Terra Cotta (clay pots) about 2" diameter and 2" tall, the hole in them slips over 3/16" rods nicely.
     
  14. Dec 4, 2019 #14

    RFMan

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    Followup to my post #4; here is a picture of the end of the launch pad...the U-bent iron strap is painted blue (extends under pad #1). The lazy Susan bearing is on the other end of the 12' long 2x4 (second photo). The short piece of 2x4 at right angles to the long one presents enough wood to secure all four holes of the lazy Susan bearing, and has two T-brackets for rigidity.

    Sorry for the photos...these were taken in about 1987 with a 110 instamatic camera :)
    4h_bearing.JPG
    4H_loaded.JPG
     
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  15. Dec 4, 2019 #15

    scadaman29325

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    Screenshot_20190818-194637_Edge.jpg Screenshot_20190818-194310_Edge.jpg Screenshot_20190818-183048_Edge.jpg

    This is what I'm going for. Still collecting the parts. Also want to use the keyless drill chucks.
     
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  16. Dec 4, 2019 #16

    rharshberger

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    We use those on all three of our LPR rod type pads.
     
    Last edited: Dec 4, 2019
  17. Dec 4, 2019 #17

    FlyingMonkey

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    I bought a folding horse and I'll be making my pivots. I would love to use drill chucks but I think i'm gonna use what I have leading around instead.
     
  18. Dec 4, 2019 #18

    scadaman29325

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    Could you post a few pics and measurements. I've heard it's tricky getting everything correct. Or lans would be great!

    Thanks.
     
  19. Dec 4, 2019 #19

    Wallace

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    The 110 with the film cartridge? I'm pretty sure if I dug around enough I could find one. Remember the disk film cameras? They totally sucked but it was a gimmick I couldn't resist.
     
  20. Dec 4, 2019 #20

    cwbullet

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    6 inch tiles work.
     
  21. Dec 4, 2019 #21

    rharshberger

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    I will try and get a materials list for our pads this evening, life was a bit busy yesterday. iirc it was about $100 materials without the folding sawhorses.
     
  22. Dec 4, 2019 #22

    RFMan

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    When the disk cameras came out, I received one for Christmas. I took rocket pictures with it too - still have some! :D

    I tend to think of the 110 film cameras as a ground-mounted Astrocam :D
     
  23. Dec 4, 2019 #23

    boatgeek

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    Standard steel sheet metal from Lowe's Depot makes a blast deflector that holds up to F and G motors for a loooong time.
     
  24. Dec 5, 2019 at 1:09 AM #24

    Wallace

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    What gauge is "standard" @ Lowes?
     
  25. Dec 5, 2019 at 2:10 AM #25

    rharshberger

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    16 or 18ga. iirc.
     
  26. Dec 5, 2019 at 2:45 AM #26

    rharshberger

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    Here is the parts list for the pads I built for TriCities Rocketeers in Eastern WA.

    3"x1"x.125"wall Rectangular tubing (approximately 6.5 foot long)

    3/4"x3" long cold rolled round stock, that I drilled and tapped for 3/8x16 thread (6 pieces required or however many stations you want, these are the round pieces coming up from the rectangular tube, cold rolled stock is easier to use as it doesn't require removing mill scale unlike hot rolled product). Its nice if the drill press has a large enough chuck to where you can chuck the round stock into the drill chuck and then mount the drill bit in the vise as it makes center drill much easier, I ended up making some kind of jig to do it as my drill press has a max size of 5/8", in hindsight I would probably down size the round stock to fit my chuck.

    1"x3/8"x2.5" long hot rolled flat stock (6 pieces used as upper section of pad adjustment mechanism, each one drilled and tapped 8-32 on the side to coincide with the 1/8" hole drilled in the top for the rod, iirc the holes were drilled slightly oversize to allow rods to easily slide in, one rod holder was also drilled for a 3/16 rod as well).

    1"x3/8"x1.5" long hot rolled flat stock (6 pieces for lower section of adjustment mechanism,these were center drilled on the end for a 3/8x16 bolt with the head cut off to be inserted and welded).

    Handwheels, plastic from Amazon, sized 3/8x16 thread and about 1.5" diameter

    The two parts of the adjustment mechanism were clamped together (one long and one short) and a 3/8" hole drilled through both on the sides for a bolt to pass through both. When possible stainless steel hardware is used.

    The first picture was the demo/prototype I made to pitch the idea to the club, there are probably 40ish hours in the building of the two 6 pad units, with the welding, drilling and tapping, possibly even including time to go get another tap as I broke one of my 8-32 taps.

    All steel parts were precut by Pacific Steel for me on their band saws, that was better as a abrasive saw doesn't do as nice job and the cuts are not always perfectly square.

    Tools needed were a drill press with vise and large enough bits to drill a slightly over 3/4" hole, 3/8" bits and bits for the 8-32 size tap. A welder and I used 1/8" 7018 rod.

    I don't remember how much the pads cost but it was about $100 dollars for materials iirc.

    Edit: the flat stock pieces that make up the two parts of the top section may have been 1/2" thick instead of 3/8" as it would have been easier to drill, my memory is fuzzy on that and the units are across town stored until next spring.


    TCR LPR PAD PROTO 1.jpg TCR LPR Pads 2018 3.jpg TCR LPR Pads 2018 6.jpg TCR LPR Pads 2018 8.jpg TCR LPR Pads 2018 9.jpg TCR LPR Pads 2018 10.jpg
     
    Last edited: Dec 5, 2019 at 3:00 AM
  27. Dec 5, 2019 at 6:04 AM #27

    caveduck

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    Out at DART we use relatively inexpensive photo tripods (about $30) with a 1/2" no-key drill chuck to make independent pads with full tilt and azimuth adjustment. To mount the drill chuck on the tripod needs only a 1/2-13 x 3/4" bolt, drilled and tapped 1/4-20 to receive the tripod stud. The blast deflector is a 4x4" or 6x6" ceramic tile (22 cents each at Home Depot for the 4") with a 1/4" hole drilled in the center. A 1/2" chuck will hold MicroMaxx rods on up, and will also hold a 10mm MakerBeam rail. It takes about 10 minutes to build one of these. We tried Spad-style pads using fenceposts and drill chucks first, but pounding a batch of them far enough into the Fiesta Island sand at every launch was way too much work, although they were cheaper. The tripods have been vastly better.
     
    Last edited: Dec 5, 2019 at 6:09 AM
  28. Dec 5, 2019 at 11:17 AM #28

    Wallace

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    And a sandbag on the tripod "spreaders" helps a ton with stability..
     
  29. Dec 5, 2019 at 11:18 AM #29

    Wallace

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    Seems like virtually every rummage sale has an old camera tripod for 5 ish bucks if Ya wanna save some dough..
     
  30. Dec 5, 2019 at 6:01 PM #30

    Winston

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    Probably thrift shops, too. I bought one of these for $57 years ago:

    Bosch 42 in.- 65 in. Aluminum Heavy Duty Quick Clamp Laser Level Tripod

    https://www.homedepot.com/p/Bosch-4...uick-Clamp-Laser-Level-Tripod-BT170/203392591


    Super heavy duty and a steal at that price. Harder to find one at that price now considering it retails for $109, but there are some Google hits at that price and some on Amazon including an even cheaper BT160 model:

    https://www.amazon.com/Bosch-Aluminum-Quick-Tripod-BT160/dp/B004EIL4R2/

    https://www.amazon.com/dp/B011QFS6BC

     
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