Vatsaas Bros Parachute Template

Discussion in 'Recovery' started by cwbullet, Jun 19, 2016.

Help Support The Rocketry Forum by donating:

  1. Jun 19, 2016 #1

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    21,181
    Likes Received:
    972
    Gender:
    Male
    Location:
    Glennville, GA
    Does anyone have this template? I lost it.
     
  2. Jun 19, 2016 #2

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    7,915
    Likes Received:
    583
    Gender:
    Male
    Location:
    Pasco, WA
    Hopefully it works, courtesy of the Internet Wayback Machine....

    This is the spreadsheet that produces the patterns based on rocket weight etc.


    View attachment chutecalc1.xls
     
    Last edited: Jun 19, 2016
  3. Jun 19, 2016 #3

    fyrwrxz

    fyrwrxz

    fyrwrxz

    latest photo

    Joined:
    Jun 6, 2011
    Messages:
    6,445
    Likes Received:
    3
    Chuck- pm Stealth6-pretty sure he still has one or several iterations.
     
  4. Jun 19, 2016 #4

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    21,181
    Likes Received:
    972
    Gender:
    Male
    Location:
    Glennville, GA
    Thanks
     
  5. Dec 28, 2018 #5

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
     
  6. Dec 28, 2018 #6

    rocketguy101

    rocketguy101

    rocketguy101

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    1,375
    Likes Received:
    15
    try this https://web.archive.org/web/20150516222737/http://www.vatsaas.org/rtv/tools/computationtools.aspx the description says

    "A descent rate calculator for for elliptical-cupped (Rocketman™) Parachutes. This calculator also provides the dimensions for making your own elliptical-cupped parachutes at precisely the size you need for your rocket. It was written as part of the how-to instructions available"

    The Vatsaas Brothers website was an amazing place to explore...it's a shame it went away...thank goodness for the internet archive! https://web.archive.org/web/20150910054712/http://www.vatsaas.org/rtv/
     
  7. Dec 28, 2018 #7

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    Thanks for the link. I tried for hours and came up empty handed...
     
  8. Dec 28, 2018 #8

    rocketguy101

    rocketguy101

    rocketguy101

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    1,375
    Likes Received:
    15
    LOL I couldn't find it directly on the Wayback Machine, so I googled "vatsaas brothers" and a hit from TRF came up, a post by chuck with the link to the home page
     
  9. Dec 28, 2018 #9

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    21,181
    Likes Received:
    972
    Gender:
    Male
    Location:
    Glennville, GA
    I need to find a sewing template for these.
     
  10. Dec 28, 2018 #10

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    My main interest is in the reduced # of shroud lines. Can't say I'm crazy about the look. I love the look of multiple gored chutes (especially ringslots/ringsails:)) but as they get past a certain point in size the number/bulk/mass and tangling qualities of the lines becomes difficult to deal with. While it would obviously be WAY easier to just buy chutes, it simply dosen't come with the satisfaction of having made them yourself.
     
  11. Dec 28, 2018 #11

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    21,181
    Likes Received:
    972
    Gender:
    Male
    Location:
    Glennville, GA
    I found a good PDF.
     

    Attached Files:

  12. Dec 28, 2018 #12

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    Perfect!
     
  13. Dec 29, 2018 #13

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    Any opinions on material choice? I really like working with 1.1oz ripstop but I've never used such large pieces for a single panel. Assuming it would be best to cut them on the bias, would 1.1oz have the necessary strength for a 40lb recovery weight? Seems like most of the manufacturers use 1.9oz for this style of chute. Is that mainly done for strength due to large panels or is it more due to economics? Packing area should not be a concern, mainly mass and the fact that the lighter weight cloth seems to open/fill/pack more easily...
     
  14. Dec 31, 2018 #14

    Handeman

    Handeman

    Handeman

    Forum Supporter TRF Supporter

    Joined:
    Jan 18, 2009
    Messages:
    7,413
    Likes Received:
    75
    Location:
    Stafford, VA
    I don't know for sure, but I would suspect it is all about economics. Most of the manufacturers will charge you more for chutes made with lighter nylon.
     
  15. Dec 31, 2018 #15

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    That's pretty much falling in line with what I'm finding as far as pricing different weight material. And being a bit more difficult to work with...
     
  16. Apr 5, 2019 #16

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    I keep loosing this thread, so making a post to keep it in my history.
     
  17. Apr 5, 2019 #17

    Wallace

    Wallace

    Wallace

    Well-Known Member

    Joined:
    Feb 16, 2017
    Messages:
    1,194
    Likes Received:
    200
    I'm a seasoned pro at losing virtually everything. No need to explain. Have you tried making one yet? I figured I'd give it a shot by making a small (20"?) drogue. Made some scaled graph paper out of dollar store poster board, "sketched" the patterns and cut the pieces out of some scrap ripstop. Very first move I made was to sew 2 of the straight sides together, then I took the time to actually look at the diagramo_O. After scrapping those, I cut 2 more and made a feeble attempt at sewing the (correct, this time) radiused sides together. Turns out it's really F'n hard to sew a doubled up seam with that tight of a curve. Flipped it over and looked at the crazy/crooked/puckered/bunched up lumpy mess and put everything in a bin in the garage. I suspect it'd be much easier with some lighter weight material. One of these days I'll pick up some more 1.1oz. and re-visit it. If anyone has success with one please post pics and pointers....
     
  18. Apr 5, 2019 #18

    beeblebrox

    beeblebrox

    beeblebrox

    8 C6-0, 12 D11-9, 20 D20-0, 20 E5-0, 3 Cinerocs

    Joined:
    Mar 19, 2016
    Messages:
    167
    Likes Received:
    18
    Gender:
    Male
    Location:
    West Chester, PA
    Does anyone know where the best place is to buy the soft ripstop nylon? I went to JoAnn fabrics the other day and all they had was the heavy stiff kind...not good.
     
  19. Apr 5, 2019 #19

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    No, I haven't tried it yet. I'm thinking about posting the link to that design on the "Mr. Excel" website and ask the experts there if they could figure out a way to have Excel actually plot the patterns with the correct grid size so I could take it to someplace like Staples and print it out full size.
     
  20. Apr 5, 2019 #20

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    Ripstopbytheroll.com would be my choice.
     
    Dugway likes this.
  21. Apr 8, 2019 #21

    Banzai88

    Banzai88

    Banzai88

    Lvl 1,Wallet....Destroyed

    Joined:
    Jul 15, 2015
    Messages:
    1,848
    Likes Received:
    182
    I'll post pics of my first attempt tonight when I get home. It's a royal pain in the butt to wrap your head around the pattern, and after a year of staring at it, I'm still not sure that I did it right.

    Ripstopbytheroll is the ONLY place to get nice ripstop that's NOT at crazy sport parachute prices. Just be aware that when you look at their website, you're likely to be overwhelmed by choices initially!
     
  22. Apr 8, 2019 #22

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    7,915
    Likes Received:
    583
    Gender:
    Male
    Location:
    Pasco, WA
    Flymarket kites iirc is fairly priced as well, and they carry the very lightweight thin mill nylons like .75oz which makes for a very small packing chute.
    https://www.flymarketkites.com/
     
  23. Apr 8, 2019 #23

    Banzai88

    Banzai88

    Banzai88

    Lvl 1,Wallet....Destroyed

    Joined:
    Jul 15, 2015
    Messages:
    1,848
    Likes Received:
    182
    I've bought some fabric from them, and it's fairly priced.......but there's some different stuff out there in the kite world that uses the same words, but it's not what you expect. The last few pieces that I got from them was not the supple, gentle fabric that we're all familiar with, it was stiff and krinkly. Not sure what the brand or designation was right now, I'd have to look that up at home.

    On another note, they're my favorite place for getting the braided dacron cord that I use for shroud lines when I can't get it from my local kite shop.
     
  24. Apr 9, 2019 #24

    dhbarr

    dhbarr

    dhbarr

    Amateur Professional

    Joined:
    Jan 30, 2016
    Messages:
    5,158
    Likes Received:
    375
    Stiff & crinkly sounds like maybe Cuben to me?
     
  25. Apr 9, 2019 #25

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    21,181
    Likes Received:
    972
    Gender:
    Male
    Location:
    Glennville, GA
    what do you need?
     
  26. May 9, 2019 #26

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    I drew one up for a 3lb rocket at 250' ASL (forgetting I'm moving to the York, VA area where I'll be, what, 12' above sea level?).

    I had to dicker with Excel to get my grids the correct size (2.25"), and when I print from Excel, the grids are correct, but if I convert it to a PDF, the grids are short (by 1/8") in the vertical axis.

    Anyway, I'm gonna cut some ripstop to shape and send it all to my cousin, who is a former costume designer/seamstress and have her give it a go.

    I also posted it (as a .xlxs file) on the Model Rocketry Fanatics Facebook page https://www.facebook.com/groups/modrf/permalink/2292223137487880/
     

    Attached Files:

    Last edited: May 9, 2019
  27. May 9, 2019 #27

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    7,915
    Likes Received:
    583
    Gender:
    Male
    Location:
    Pasco, WA
    It wont take the .xlxs but it will iirc take .xls the older format.
     
  28. May 9, 2019 #28

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    Thanks! I Googled and it said to save it as a Microsoft Excel 97-2003 Worksheet. I did, and re-opened it and it all looks the same, so let's see if anyone has any trouble with it.
     
  29. May 9, 2019 #29

    crossfire

    crossfire

    crossfire

    Lifetime Supporter TRF Lifetime Supporter

    Joined:
    Jan 16, 2011
    Messages:
    3,288
    Likes Received:
    120
    That type of ripstop is used a lot in kite building. We never like it for chutes.
     
  30. May 15, 2019 at 12:33 AM #30

    JonathanOtt

    JonathanOtt

    JonathanOtt

    Well-Known Member

    Joined:
    Jun 13, 2015
    Messages:
    264
    Likes Received:
    39
    Gender:
    Male
    Location:
    Fayetteville, NC
    I'm guessing that the template does not need to be dead nuts on, right? I mean if I'm supposed to hand draw out a grid then hand draw in the curves for the template, .001" accuracy is not really required.

    I used the template I drew out last week, then made a better (IMHO) one piece template that is just a little bigger in some spots on the curves and is a symmetrical as I can do it using what I have (Microsoft Publisher).

    I've attached a couple examples.

    The first "Overlay" is my original pattern (red lines) overlain on my updated pattern (black line/orange fill) and you can see it's a little bigger in the "Y" axis, and pretty danged close in the "X" axis.


    The second "Layout" is how it'll look when the patterns are cut, laid out and ready to sew (no seam allowance).


    The third "Modified shape with hem allowance" in my vision of it, if I were to transfer it to the fabric, in one large piece. Fold it on the centerline (Y), stitch the interior seams together; open it up, fold on the other center line (X), stitch the interior seams. I'm thinking a French-fell seam would be best (lays flat and super strong, if not a real bear to stitch on a curved and rounded piece).

    [​IMG]


    I printed out a paper "model", trimmed it to the colored lines, folded and stapled it together (very high tech). It looks like it'll work out. It kinda looks like a 2/3 sphere with notches cut into it.

    If I invest in actually producing one of these, I'm going to test it (rigorously) by throwing it off a building with a two-liter bottle full of water (~4.4 lb/2kg) which calculates (by the Vatsaas spreadsheet) to 18 ft/sec -- 12.3 mph. I can always adjust the water level to lighten it up to actual "flying" weight.
     

Share This Page