Airbeam Development, 5.5 psi

Failure sometimes can be healthy for the soul, but it is always good for your tech.

We have spent the last month gluing reinforcement strips around the Ascender airbeam rib. We could never get the rib above 3.2 psi without bursting. We needed to get it to 3.4 psi. This gives us a 100 percent safety margin over the 1.7 psi operating pressure. We tested the glued seams on a straight airbeam and we were able to reach 3.5 psi. Expectation were high for big rib test.

The team had the rib up to 2.4 psi then BLAM! (it really was incredibly loud) 2.4!!!????!!!! What was that all about. Discouragement all around. A three foot section of the rib was completely shredded, we were done for the night.

The next day out of shear frustration we cleared the day and decided to fix this problem. We had been chasing this a bit too long. Airbeams are normally made with heavy, very strong materials. Our requirement is to make it work with ultra lightweight nylons and thin film plastics so just turning to canvas was out. The result was light ribbon loop around the beam, bit NOT attached in anyway to the beam. Ribbon banding, or ribs on the rib. The first set of ribbon loops would make a sound like a shotgun when failing. The second general of loops held. By the end of the day we completely blew pass the 3.4 goal and hit 5.5 psi. We could have gone higher but didn’t want to risk damaging the end caps if it blew. The ribbon banding is only slightly heaver than the glued seam reinforcement.

The next day, Saturday we put the beam through it’s paces. We conducted load tests with the beam spanning a five foot gap. We spend the day putting loads from 5 to 38 pound on the beam at pressures from 1 to 4 psi. Now it’s on to repair the big rib.

All is well, so far...

All is well, so far...

Blam!

Blam!

Slow reaction time...

Slow reaction time...

5.5 psi !!!!!

5.5 psi !!!!!

Under load

Under load

Measuring defelection

Measuring defelection

Banded Beam

Banded Beam

One Response to “Airbeam Development, 5.5 psi”

  1. K7AAY says:

    Grammar gremlins suggest these changes to
    http://jpaerospace.com/blog/2009/07/27/airbeam-development-55-psi/

    Expectation were high for big rib test.

    Suggest adding the missing article of speech:

    Expectation were high for the big rib test.

    -

    What was that all about.

    Suggest change to read:

    What was that all about?

    -

    A three foot section of the rib was completely shredded, we were done for the night.

    Suggest change to:

    A three foot section of the rib was completely shredded, so we were done for the night.
    -

    The next day, Saturday we put the beam through it’s paces.

    Suggest change [color=#FF04000]it’s[/color] to its

    -

    The next day out of shear frustration we cleared the day and decided to fix this problem.

    Suggest change [color=#FF04000]shear[/color] to sheer

    -

    The result was light ribbon loop around the beam, bit NOT attached in anyway to the beam. Ribbon banding, or ribs on the rib.

    Suggest change to:

    The result was light ribbon loops around the beam, but NOT attached in anyway to the beam; ribbon banding, or ribs on the rib.

    -

    Many thanks for doing the work and keeping the dream in the air!