Two Tubes

Of of the main concerns with our new tubes is how they will perform as a duct. Having just our original duct the only way to get any clue was to compare those against each other. How ridiculous it may sound, while different lengths (1m and ~6m) – both tubes still share one essential parameter the inner diameter 60mm.

There is also EDF from our jet-cart project, which can be transferred around and we can use it for comparison together with our old friends – 2kW PSU and high-speed Anemometer.

Test #1

Asking Seb to assist we did a test with original tube first.

As you can see, we removed the vector thruster for now and measured peak at 16.84 m/s.

Test #2

Setting up our new [6m] tube took little bit longer, some cutting and some taping was needed.

Being little bit worried about all that contraption not flying away we did a tiny test run.

All good, now ready to roll.

Well and that is where became quite surprised. As you can see, peak came up to 20.32 m/s! That’s quite a different value to our original measurement of 16.84 m/s. Having same tube diameter, EDF, and power levels – I am more then happy to see 20% power increase, but it also horrifies me that goes completely against our assumptions (expected was 20 – 40% decrease).

I assume that using the Watt-meter might tell us if the higher output observed correlates with higher power consumption, or if we’ve been really somehow able to increase a tube performance. No idea what sort of physics might be behind it, unless tube getting seriously heated by Queensland’s sun.

Any idea, anyone?