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Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Paint it with a water based paint first. White matt emulsion should do it. Put a few layers on, leave it to dry, then paint with whatever you want. (within reason)
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Ash Small wrote ...
Paint it with a water based paint first. White matt emulsion should do it. Put a few layers on, leave it to dry, then paint with whatever you want. (within reason)
I suggest matt black blackboard paint.
ill try ther Krylon H2O latex spay paint in black, then switch over to other colors once teh base black is dry. im thinking that the ducts should be almost disposable (meaning cheap, and plentiful).
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
BigBad wrote ...
cynical rules lawyering: In this thing, are there constraints on size in flight, or only when being examined?
it must fit within a 1m^3 box, (XYZ must be less than 1m), doorways are exactly 1m (39 in) wide, my machine is 29 inchs wide atm. but i can get it down to 22 inches wides with some minor mods.
obviously your a fool if your trying to navigate A 38 inch wide robot through a 39 inch wide opening. The michigan teams bot is about 16 wide and long.
so a wise engineer will realize going to big or too small presents problems for robot posistioning and sensory detection, so therefore ther must be a compromise for an optimised implimentation. (which every team is despreately trying to figure out)
Registered Member #2529
Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600
Actually that's interesting; from efficiency POV you'll get extra lift if you go as close as possible to the walls, both sides, because it will interfere with the vortexing.
Also, you want to be as close to the floor as possible, as much as possible; due to ground effect.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
BigBad wrote ...
Actually that's interesting; from efficiency POV you'll get extra lift if you go as close as possible to the walls, both sides, because it will interfere with the vortexing.
Also, you want to be as close to the floor as possible, as much as possible; due to ground effect.
about the ground effect, there was a team that only used a hover hovercraft bzck in 1989 (or so) so the judges changed the rules, now you have to demonstrate free flight above ground effect, but you can decend back towards the ground later... its just that to complete the task you kinda have to be at about 4 feet AGL, im sure they've arranged it like this on purpose!
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155
@Patrick Styrofoam safe spray paint is also at the same craft store I mentioned. Check the labels to ensure it is specifically noted as such.
@BigBad Depending on the aircraft, the ground effect can dominate within 1 prop radius of the surface, but in this case would be more closely related to a "deflected slipstream" problem.
Alternately, some craft use shrink-fit adhesive vinyl for skin:
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
ive looked into monokote, will use if it becomes advantageous to do so.
right now im trying to figure out how to use Pinky's source on teh use of ducts... 0.03% of a diam is 0.030" fo my prop. so getting the duct to wobble and bend less than 0.060" overall is tricky, though i have made and painted the first duct already.
Registered Member #2529
Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600
Patrick wrote ...
BigBad wrote ...
Also, you want to be as close to the floor as possible, as much as possible; due to ground effect.
about the ground effect, there was a team that only used a hover hovercraft bzck in 1989 (or so) so the judges changed the rules, now you have to demonstrate free flight above ground effect, but you can decend back towards the ground later... its just that to complete the task you kinda have to be at about 4 feet AGL, im sure they've arranged it like this on purpose!
Sure, you should be able to fly at any height, but for example, bouncing up away from the floor, through a hoop or whatever they have, and then going back down and catching yourself right before hitting the floor saves power. Any thrust you generate you want to do that within one rotor radius of the floor; it probably as much as doubles your longevity/halves the battery pack size/mass, or even more, because that's mass you're not carrying, which in turn saves energy which saves more battery; and you can calculate the convergent series.
So it's a control strategy that enables you to reduce the mass.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
BigBad wrote ...
because that's mass you're not carrying, which in turn saves energy which saves more battery; and you can calculate the convergent series. So it's a control strategy that enables you to reduce the mass.
yes ill agree, but that assumes i have a useful 2-D SLAM and decison making model.
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The Physics Of Propellers (And Electrical Motors).
