Modern version of TPG - Or the search for "Black Wood"

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by BBerson, Nov 27, 2019.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Dec 4, 2019 #221

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member Lifetime Supporter

    Joined:
    Jan 24, 2011
    Messages:
    4,247
    Likes Received:
    1,976
    Location:
    US
    Look at prices for both of these things, you'll have your answer. Nyet.

    The string for the ribs doesn't have to be strong, it just needs to hold the CF up while it cured. In fact, weak might be better as we'll eventually need to cut across it.
     
    Last edited: Dec 4, 2019
  2. Dec 4, 2019 #222

    Topaz

    Topaz

    Topaz

    Super Moderator Staff Member

    Joined:
    Jul 30, 2005
    Messages:
    13,963
    Likes Received:
    5,577
    Location:
    Orange County, California
    Give me a bazillion bucks, and I'll be happy to try them out for you. :)

    Part of the "problem" here is that we already have perfectly adequate and reasonably priced methods of building airplanes. Searching for something better is fine, but it would have to meet all the requirements of homebuilding, including those that the existing materials meet. Including cost. I'm absolutely sure it's possible to come up with "something better" by some absolute engineering metric. But if nobody can afford to work in that material or method in their garage, with home tools, it rather misses the point.
     
  3. Dec 5, 2019 #223

    Volzalum

    Volzalum

    Volzalum

    Member

    Joined:
    Nov 22, 2019
    Messages:
    8
    Likes Received:
    3
  4. Dec 5, 2019 #224

    Topaz

    Topaz

    Topaz

    Super Moderator Staff Member

    Joined:
    Jul 30, 2005
    Messages:
    13,963
    Likes Received:
    5,577
    Location:
    Orange County, California
    You can make your own epoxy if you have the chemicals. Or your own carbon fiber, with a lot more work.

    Do you really think you can make aerogel with consistent-enough mechanical properties with this kind of rig to be useful as a structural material? Or even use any aerogel as a structural core in an aerospace-grade structure? My understanding is that the stuff, despite looking like "solid smoke", is rather brittle. That makes for a bad sandwich core.

    It has to be more than "light". It has to have all the right properties.
     
    pictsidhe likes this.
  5. Dec 7, 2019 #225

    stanislavz

    stanislavz

    stanislavz

    Well-Known Member HBA Supporter

    Joined:
    Aug 22, 2016
    Messages:
    375
    Likes Received:
    97
    Location:
    Lt
    blane.c likes this.
  6. Dec 8, 2019 #226

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,494
    Likes Received:
    2,525
    Location:
    Port Townsend WA
    I like that.
    I need to know the polystyrene face sheet thickness and total sandwich weight per square foot?
     
  7. Dec 8, 2019 #227

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member Lifetime Supporter

    Joined:
    Jan 24, 2011
    Messages:
    4,247
    Likes Received:
    1,976
    Location:
    US
    The tech info PDF at their site says the 5mm thick version weighs 1kg per sq meter (0.20 lb per sq ft), the 10mm thick version weighs 1.9 kg per sq meter.
     
  8. Dec 8, 2019 #228

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,494
    Likes Received:
    2,525
    Location:
    Port Townsend WA
    .20 lb per sq ft is almost the same as .23 for aircraft aluminum (.016")
    So not light enough to interest me. Thanks.
     
  9. Dec 8, 2019 #229

    stanislavz

    stanislavz

    stanislavz

    Well-Known Member HBA Supporter

    Joined:
    Aug 22, 2016
    Messages:
    375
    Likes Received:
    97
    Location:
    Lt
    Added photo from pdf :

    [​IMG]
     
  10. Dec 8, 2019 #230

    sming

    sming

    sming

    Member

    Joined:
    Apr 10, 2019
    Messages:
    23
    Likes Received:
    10
    Thats about 200kg/m3 right? 3 times heavier than usual airex foam... perhaps the combination of high/low density still gives you some interesting edge?
    Remind me of "foam board" used by rc guys nowadays, that would be a fun construction process! Build giant rc plane with knife and glue, then glass inside/outside, done :)
     
  11. Dec 8, 2019 #231

    cheapracer

    cheapracer

    cheapracer

    Well-Known Member

    Joined:
    Sep 8, 2013
    Messages:
    5,683
    Likes Received:
    4,096
    Location:
    Australian
  12. Dec 8, 2019 #232

    sming

    sming

    sming

    Member

    Joined:
    Apr 10, 2019
    Messages:
    23
    Likes Received:
    10
  13. Dec 8, 2019 #233

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    7,223
    Likes Received:
    2,064
    Location:
    North Carolina
    When synthetic spider silk becomes available, things will change. It does have a low modulus, though
     
    Last edited: Dec 8, 2019
  14. Dec 8, 2019 #234

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    7,223
    Likes Received:
    2,064
    Location:
    North Carolina
    Hmmm, silk might make a good facing for coroplast.
     
  15. Jan 6, 2020 #235

    lr27

    lr27

    lr27

    Well-Known Member

    Joined:
    Nov 3, 2007
    Messages:
    3,341
    Likes Received:
    487
    Just to be annoying, I'll point out that, in the actual Strojnik method, the sheet can't sag because it's over a solid form, not ribs. The sheet is applied to the ribs after the bend is set.

    I've sometimes thought that a good variation would be to make a female mold over the male plug. Then drape heavy polyethylene and the sheet over a fat dowel (handrail?) and bag it into the female mold. Then you could use a thin core with it.
     

Share This Page



arrow_white