Rob, I have some questions regarding the purpose of the slanted bottom.
I've seen where you've stated that the bee's arrival into the bottom is basically a gentle arrival being as the bee is going from the restricted vacuum of the 2-1/2" hose into the 20x14x? (8-frame mediums for me...maybe two stacked...13"?) cavity of the bottom box where the vacuum (and thus wind/turbulence) will decrease to a very low pressure that the bees can handle easily. With that understood I don't see the slanted bottom as being there to give the bees a sloped landing surface rather than a "wall" to slam into.
The questions I have (for now<g>) are:
Is the slanted bottom intended to encourage the bees to move upward?
Is the slanted bottom an engineering design to aide the air-flow?
What would be the consequence of not having a slanted bottom?
Do you hang any frames in the lower bee box (maybe to the sides) to give the bees somewhere to cluster/hang during the cut-out?
I've watched the three videos of yourself detailing the features and use of your vac design and I'm pretty well sold on the idea. I thought at first the bucket-vac would do me ok (I still like Rick Hall's bucket design), but the functionality of the Bushkill design keeps drawing me in. ;) Of course, my inapt skills as a woodworker may hinder me in this project...but, if I can move some other projects to the side this winter I'll have a vac by spring. :)
Sorry to bother you with questions that are probably very evident to most folks.