Torsten Spitzner Posted September 6, 2020 Share Posted September 6, 2020 I have been asked to share the details of this little jumper, so I shall give it a go...... There is not much detailed info on the net, not that I could find in any case. The plans for this jumper are on Outerzone but I found the original build article to be somewhat unclear in places and some changes and figuring out were necessary. Nothing new there... I really enjoyed making this model since it was something completely different and Jumper Mk2 is planned, with the cardboard templates already made. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 6, 2020 Author Share Posted September 6, 2020 The first thing to do was to print the plan full size. I printed in tiled format at home and taped the pages together.. Then got things ready.. Quote Link to comment Share on other sites More sharing options...
stu knowles Posted September 6, 2020 Share Posted September 6, 2020 Interested! Quote Link to comment Share on other sites More sharing options...
Glenn Philbrick Posted September 6, 2020 Share Posted September 6, 2020 Very interested. We have tried many variants with mixed results., and some we've never seen again! Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 I started by making the 'torso" of the jumper. essentially this is just a box which will contain the radio gear. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 As I recall, the 'torso' is made from balsa. I used ply for the top part (where the head attaches onto). I remember telling myself at the time, that I should have made the entire torso from 3mm ply. But so far he has held up to the parachute opening forces. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 Some balsa triangle in the corners.. Hardwood strips was glued into the top 'torso' corners. The harness mounting would later be screwed/attached into these. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 Okay, looking at that last picture, both top and bottom 'torso' pieces were ply, with the sides being balsa. The the ply leg mounting doublers were made Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 The leg mounting doublers were drilled for the shaft. the legs need to be able to swivel, or rotate forward. During freefall, a skydiver needs to be in a 'stable' position, called an 'arch'. When this little skydivers parachute is deployed, the legs need to rotate forward a little, into a more vertical position. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 The next picture should show what I am doing. The leg support/attachment is balsa with ply doublers on the outside. The hole drilled through the centre then gets a piece of brass tube epoxied into it. This is for the piano wire axle which are epoxied into the two legs. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 7, 2020 Author Share Posted September 7, 2020 The next series of pictures relate to the container construction. ( the container holds the parachute), as per plan. Ultimately, I abandoned this entire method and made something much simpler. I couldn't get the designed container to open reliably. So I'll post the original idea just for continuity. Edited By Torsten Spitzner on 07/09/2020 12:52:50 Edited By Torsten Spitzner on 07/09/2020 13:01:14 Quote Link to comment Share on other sites More sharing options...
FilmBuff Posted September 7, 2020 Share Posted September 7, 2020 Looking with interest! Quote Link to comment Share on other sites More sharing options...
Glenn Philbrick Posted September 7, 2020 Share Posted September 7, 2020 I have found the plans but how did you print them out larger all I have is one A4 sheet. Quote Link to comment Share on other sites More sharing options...
Guest Posted September 7, 2020 Share Posted September 7, 2020 Glenn Open the file in Adobe Reader. Choose print and on the dialog select the "poster" option. This will pint oversize drawings onto several A4 pages. Pick the "cut marks" and you'll get small markers to do the trimming (I use a guillotine) then pritt stick or tape the pages together matching the marks. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted September 7, 2020 Share Posted September 7, 2020 Another thing to ensure is that you have the scale set 100% as I see Nigel has done but you can select other scales. It's surprising how accurate the print is - at least it is with my printer. Geoff Quote Link to comment Share on other sites More sharing options...
Glenn Philbrick Posted September 7, 2020 Share Posted September 7, 2020 Thanks. Now I can see whats going on Glenn Quote Link to comment Share on other sites More sharing options...
Guest Posted September 7, 2020 Share Posted September 7, 2020 Glenn, Just to give another useful print option - especially when you want rib profile/Formers without tracing. You can use the snapshot option, and print at custom scale. This means you can print small sections of a plan onto a single sheet (stick to wood with thinned PVA) etc. Draw around the bit you're interested in... rectangle shown below. Then select print... Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 The 'take a snapshot' function is most useful, I use it regularly to print small parts of plans. Small hooks and rings were made up from piano wire and the container cut as per plan from suitable material. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 The backing plate was cut from 2 or 3mm ply and some ply reinforcing was glued to the sides as the hooks and rings would be attached to these. I used contact adhesive here. Edited By Torsten Spitzner on 08/09/2020 08:26:07 Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 The following series of pictures will hopefully explain the procedure. This whole design is over complex imo. When the pin is pulled, the elastIc bands are supposed to pull the two container sides open. I found this to not work reliably. Important to note also, is that the container size was hopelessly too small as per plan. The first test parachute would fit but subsequent ones, made from thicker material, would not. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 In the meantime, I was also making a test parachute. This was simply made from refuse bags which were taped together. Regular string was used for the lines, a weight attached and taken for a test from from a suitable plane. This demonstrated that the concept was good and work on the model continued. The first problem was that the pattern for the gores (parachute panels) did not work out correctly. Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 Google to the rescue and I found a method to divide a circle into 14 equal parts, adding some for the overlaps. A card template was made and the gores cut to size I used the grouting lines on my tiled floor as straight edges The gores are laid out and taped together. There needs to be an overlap at each join, which creates a pocket, or sleeve, through which the lines are threaded. The lines are pulled through the gores. One line goes right through from one side, through the top and is the same line on the opposite side. The lines are knotted at the top, where the pilot chute will be attached later. The first test parachute is ready for testing. Quote Link to comment Share on other sites More sharing options...
Glenn Philbrick Posted September 8, 2020 Share Posted September 8, 2020 Thanks for the help with Adobe reader, I was not aware of the usefulness of this program. ow that I can se the full size the biggest challenge for me is going to be the parachute itself. So I relieved to see the latest batch of photos which offer some encouragement. Glenn Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 8, 2020 Author Share Posted September 8, 2020 The harness risers were made from wide shoe laces and small rings sewn on using waxed dental floss. The test chute was packed and put into the container. Of course, I had to learn how to pack a round parachute as well... Quote Link to comment Share on other sites More sharing options...
Torsten Spitzner Posted September 9, 2020 Author Share Posted September 9, 2020 OOps, cleaning out the photo album obviously deletes the pictures from the thread as well I shall continue none-the less... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.