How long did you let the samples cure for before trying the water test because if you look closely at the directions on the the Mod Podge label it says it has a four week cure time. Might change the results if your willing to put in the time.
You should definitely try building a plane on your own from scratch. 3D printing has advanced a lot and can make som pretty strong, lightweight parts, and it'd allow you to start with a theoretical goal in mind of what speeds you want, and work backwards. It would also let you design in a spot for a camera (behind the windshield?), allow you to hide mechanical parts within the airframe, you could make it modular to test out different wingshapes, etc, build in a place inside the fuselage for the motor to sit so the thrust is inline, and you would probably get an overall better, sleeker exterior, especially since with all the hacks you made to the plane, the skin looked pretty beat up. Also, I'd imagine the aerodynamics the SR71 was designed for are probably different on the models scale. It would be a hell of a lot of work, but I personally would love to see your whole design process. Could make for a cool series! Anyway, awesome vid as always, this series of you trying to push for higher speeds is awesome and makes me think of what it must have been like for the engineers in real life whose job it was to do this stuff.
Just a quick message, even if you're doing rudimentary smoke tests you want to have the smoke flowing as slow as possible, so that you can see the true impact the fans are having. Having the flow rate that high ruins your ability to actually see what's going on because the air is already accelerated near the speed of the exiting air.
