Help Support RocketryForum by donating using the link above or becoming a Supporting Member.


Page 2 of 2 FirstFirst 1 2
Results 31 to 39 of 39
  1. #31
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    Before I can proceed with the chassis frame, I need to confirm the distance between the upper "axle" and the lower "uplock" of the truss. I am using a TR-4081 (3 meter) segment of F33 Global triangular truss, which has 2" vertical tubing with 3/4" individually welded diagonal bracing. Since the truss tower has to come off the base for transport (design spec - fitting inside my 10' vee-nosed trailer), I am using Global Pro Clamps to securely attach the truss to the hinge bracket. These clamps wrap around the vertical tube which limits their position in the areas of diagonal bracing. Here is progress on the axle bracket... a 4" x 12" x 1/4" steel plate with the Pro Clamps on one side and a pair of mounted sleeve bearings on the other. The sleeve bearings allow the whole truss to rotate around a 5/8" shaft mounted on uprights of the base.

    Fortunately, my dad taught me how to drill steel when I was a kid. The drill bit is a much harder steel than the steel you are drilling into, and will have no problem shaving off metal as long as it keeps its edge. Keeping the edge is where the bit needs help. Drill a pilot hole first, and keep the bit cool, using a medium oil and keeping the drill turning slow. Torque is your friend, not speed. By switching belts around on the pulleys of my drill press, I got the speed down to a leisurely 240 RPM. After holes drilled, deburred edges with a larger bit.

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	61ge+z26VxL._SL1000_.jpg 
Views:	41 
Size:	97.9 KB 
ID:	326695   Click image for larger version. 

Name:	060116-proclamp.jpg 
Views:	41 
Size:	25.3 KB 
ID:	326696   Click image for larger version. 

Name:	IMG_3465.jpg 
Views:	47 
Size:	663.6 KB 
ID:	326689   Click image for larger version. 

Name:	IMG_3471.jpg 
Views:	45 
Size:	671.8 KB 
ID:	326688   Click image for larger version. 

Name:	IMG_3473.jpg 
Views:	48 
Size:	642.4 KB 
ID:	326687  

    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

  2. #32
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    Assembled upper "axle" plate ready to go. Lower "uplock" plate next to fabricate.

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_3676.jpg 
Views:	46 
Size:	221.1 KB 
ID:	326693   Click image for larger version. 

Name:	IMG_3678.jpg 
Views:	48 
Size:	228.6 KB 
ID:	326692   Click image for larger version. 

Name:	IMG_3664.jpg 
Views:	50 
Size:	135.2 KB 
ID:	326691   Click image for larger version. 

Name:	IMG_3670.jpg 
Views:	48 
Size:	68.2 KB 
ID:	326690  
    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

  3. #33
    Join Date
    27th July 2014
    Location
    south beloit, IL
    Posts
    1,922
    Sather- will we see this pad at MWP?
    NAR# 99285
    Tripoli# 16283
    L1- 4/26/2015 Madcow Cowabunga- H123SK
    L2- 11/1/2015 Wildman Darkstar 2.6- J355RL
    Woosh
    QCRS

  4. #34
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    Quote Originally Posted by djs View Post
    Sather- will we see this pad at MWP?
    Probably not this year. First excuse is I tend to build really slow... I have discovered that whenever I rush, I mess something up. Since I don't really have a plan, I am intentionally going slow to avoid having to back-pedal. Grinding off welds is not fun. Secondly, this is technically a school rocket club project, so keeping the construction pace loosely tied to the school year. We hope to inaugurate her at a spring launch.
    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

  5. #35
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    Continuing progress on the 1:4 scale model. I brought it to a Fox Valley Rocketeers meeting, where good friend Ed C. challenged me to make it functional rather than just be a parts buck. First thing it needed is a scale truss, which AFAIK is not available commercially. So, off to the workshop we go. The 10' Global triangular truss I plan to use on the full-size pad has 2" tubes, with 3/4" bracing, (perpendicular bracing at the top and bottom and 11 sets of diagonal bracing). Made a quick jig set to the angle of the diagonals and made 33 of them in 1/4" dowel, with 6 more straight cut shorter pieces for the top and bottom. The 2" x 10' tubes are 1/2" x 30" dowel. Used a pair of cardboard jigs to hold them in place when gluing the end bracing, then carefully cut the cardboard off. I found the easiest way to attach the diagonal bracing was with the truss vertical, letting gravity hold them in place I could work from the bottom up, around the tower, and do them all in one session. Will add some better fillets to approximate the welds and paint silver. Next step is to make scale models of the axle plate and uplock plate.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_3698.jpg 
Views:	48 
Size:	136.3 KB 
ID:	327603   Click image for larger version. 

Name:	IMG_3701.jpg 
Views:	51 
Size:	102.8 KB 
ID:	327602   Click image for larger version. 

Name:	IMG_3712.jpg 
Views:	58 
Size:	108.5 KB 
ID:	327601   Click image for larger version. 

Name:	IMG_3714.jpg 
Views:	64 
Size:	194.9 KB 
ID:	327600  
    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

  6. #36
    Join Date
    23rd July 2011
    Location
    Butte, MT
    Posts
    1,811
    Really nice work.


    Steve Shannon
    Steve Shannon
    L3CC, TAP, Director, Tripoli Rocketry Association

  7. #37
    Join Date
    21st April 2010
    Location
    So central WI, USA
    Posts
    5,318
    methinks that you need a suitably sized rocket to pose on the small version .
    Rex
    L2-competitor 3, AT J350W, 8/27/2016, Bong, 2557'
    my youtube channel http://www.youtube.com/channel/UC0gB...?feature=watch

  8. #38
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    Thank you, Steve. And that is a really good idea, Rex - I will work on that.

    In the meantime... math stuff goes here, which is what I’ve been stuck on for the last two weeks… (Bear with me here, writing this down helps me think it through and gives my fellow math geeks a chance to check my work).

    I planned on using two 3/4” clevis pins as uplocks, sliding through holes cut into a cross beam of the upright support and the uplock bracket of the truss. A 3/4” hole drilled through a 2” x 2” leaves 5/8” of undisturbed steel steel on either side to take the load. I assume at least 1/2” should be adequate. (Shout out to the engineers in the crowd - call me on this if I’m wrong. I could go down to a 5/8” clevis pin , leaving 11/16” on either side.) The centerline of this hole is 1” from the truss-facing side of the 2” x 2”, and 1” from the base-facing side. (Since the ends of the 2” x 2” square tube cross member is notched to fit flush inside the 2” x 2” angle iron vertical support, the centerling of the hole is 3/4” from the truss-facing edge of the vertical support.)

    The pivot bracket plate - taking in to account the two opposing bearing brackets, the Global Pro clamp, and the 1/4” steel plate sandwiched between them, the legs of the truss and vertical support for the pivot end up being 2.34” apart, inside edge to inside edge.

    The uplock bracket - the distance between the legs of the truss and the centerline of the clevis pin hole, when the truss is vertical, is 1.59”. (2.34” less the .75” the hole is from the inside edge.) I couldn’t use a 2” x 2” for the uplock bracket, as leaving the requisite 1/2” of undisturbed metal on the outside edge of the drilled hole would bring the truss past vertical in order to line the holes up.

    Since the vertical support is 1/4” thick, an angle iron attached to the truss as an uplock bracket, and fitting BETWEEN the vertical supports must also be less than 2.59” deep or it would hit on the frame of the base before the truss becomes fully vertical. So a 3” x 3” is also ruled out as the uplock bracket.

    The initial solution is to take a 3” x 3” and rip (a woodworking term) 1/2” from one edge, essentially creating a 3” x 2 1/2” piece of angle iron, to give it just under a tenth of an inch (0.9") of clearance on the frame when locked up. Putting a 10” abrasive wheel on my table saw should allow me to (slowly) cut off a strip on one side, allowing for the thickness of the wheel, to leave a 2 1/2” piece on the base facing side. Drilling the 3/4” clevis pin holes 0.91” from this edge (1.59” from the other edge) gives a 0.535” piece of undisturbed metal on the outside of the hole. With the truss vertical, the distance between the truss leg and the upright support, edge to edge, is 2.34” (1.59” + 3/4”).

    First photo shows the initial cut on the uplock bracket. 13" long, to allow for U-bolts to attach it to the truss. Edges to be deburred, faces to be wire-wheeled (grind rail factory evidently didn't bother to paint parts that didn't show), and then 1/2" ripped off one edge before drilling.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_3728.jpg 
Views:	26 
Size:	194.2 KB 
ID:	328090   Click image for larger version. 

Name:	Screen Shot 2017-09-15 at 3.36.32 PM.png 
Views:	24 
Size:	95.1 KB 
ID:	328089  
    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

  9. #39
    Join Date
    15th May 2009
    Location
    Northern Illinois Rocket Assembly and Test Facility (NIRATF)
    Posts
    1,907
    I drilled 8 holes in the uplock plate for the 4 U-bolts. The truss advertises a 290mm total width, with 50mm (roughly 2") main tubes. Doing a little math, I figured 240mm center to center, marked these on the uplock plate, and then marked holes for the 2" I.D. x 3/8" U-bolts at 1 3/16" on either side of that. Bracket fits nicely between diagonal bracing, with the ability to move up or down a total of 3". Next up is ripping off the 1/2" from the top side of the plate. Then starting the vertical supports of the base.

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_3753.jpg 
Views:	27 
Size:	134.0 KB 
ID:	328545  
    Proud member of WOOSH, FVR, IR, QCRS, (RC)2
    2013 APCP: 48,397.3 Ns (18% P)
    Highest altitude achieved: 21,981' AGL

    "Gravity is a cruel and unpredictable mistress"

Similar Threads

  1. And for something completely different.......
    By GDJ in forum Rocket Boosted Gliders
    Replies: 3
    Last Post: 20th November 2011, 07:08 AM
  2. Something Completely Different
    By charlienorth in forum Scratch Built
    Replies: 43
    Last Post: 18th January 2007, 11:17 AM
  3. and now for something *completely* different!
    By Elapid in forum High Power Rocketry (HPR)
    Replies: 17
    Last Post: 21st July 2005, 07:37 PM
  4. And now for something completely different
    By shreadvector in forum The Watering Hole
    Replies: 3
    Last Post: 18th March 2005, 06:35 PM
  5. And now, for something completely different...
    By vjp in forum The Watering Hole
    Replies: 8
    Last Post: 25th February 2004, 06:10 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •