Great Moments In Science

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  • greasybob
    Senior Member
    • May 2008
    • 1590

    #16
    My first jet pack experience was some what underwhelming.

    Comment

    • Matt
      Senior Member
      • Dec 2008
      • 328

      #17
      Just being able to say the phrase "jet pack experience" gives you major street cred in my book Bob.

      Comment

      • Gearbreaker
        Junior Member
        • Feb 2017
        • 4

        #18
        Transformer.....

        Originally posted by greasybob
        I knew I could do better than just 6 volts AC so I improved my design. I coiled up some 22 gage magnet wire, built a circuit of a 4 diode rectifier bridge and added 5, 50 volt capacitors in series. Now I got 150 volts of nice smooth DC .
        Try a steel bolt with the coils next to one another rather than inside one another.... I'm curious if the power factor will be increased. Hmmmmm.

        Comment

        • greasybob
          Senior Member
          • May 2008
          • 1590

          #19
          Sounds like a step up or step down transformer. You want volts or amps ?

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #20
            Maybe make a Hybrid Go Cart with regenerative brakes a washing machine motor and ten tractor batteries.

            Comment

            • Estandfes0
              Junior Member
              • Mar 2017
              • 8

              #21
              Originally posted by Witsend
              Maybe make a Hybrid Go Cart with regenerative brakes a washing machine motor and ten tractor batteries.

              Sounds safe to me!

              Comment

              • greasybob
                Senior Member
                • May 2008
                • 1590

                #22
                Hot rotors, this is from a 2010 Subaru that had a brake caliper that was hanging up. While this rotor was hotter than the rest it's the heat distributuion on the rotor that caused me to stop and think. What's going on here ? You would think that the hottest part of the rotor would be the friction surface but the camera show the heat to be concentrated on the hub and the fins. Two thoughts come to mind. First, this is the way the rotors are supposed to work, drawing the heat away from the friction surface. Or, it's the nature of thermo cameras. The friction surface has a more reflective surface and the camera has a harder time measuring the true temperature. ???? More experimentation is in order I think.
                Attached Files

                Comment

                • Witsend
                  Banned
                  • Nov 2012
                  • 2942

                  #23
                  A 2010 Subaru is not a Chrysler product. It just sounds too new to have a problem with a stuck caliper. Did you crack the bleeder to see if it releases the drag on the rotor?
                  I love the Big Picture view of the temperature ranges of the thermal imager, but somehow still getting by with my $25 Port Cargo Thingy that 10 years ago introduced as new hi tech might have set one back several Hundred bucks on the truck in The Blue Dildo Line. In 5 years Thermal Imagers will be getting dumped at Port cargo for sixty nine ninety five.
                  Attached Files
                  Last edited by Witsend; 05-06-2017, 08:28 AM.

                  Comment

                  • David Green
                    Senior Member
                    • Oct 2009
                    • 382

                    #24
                    I've got one of them $25 thingy heat sensor measuring devices, well its not $25 over here LOL, it's a bit more £££ but same thing. I'm impressed with the thermal images from the new toy, my dealer keeps trying to sell me one, but not sure how I would make any money back from it.

                    I have a full computerised roller brake tester so no need for it there, don't do much if anything with heated seats, mirrors etc at the moment, nobody ever complains about that sort of stuff at our place.

                    Comment

                    • Crusty
                      Senior Member
                      • Dec 2007
                      • 2450

                      #25
                      Originally posted by greasybob
                      Hot rotors, this is from a 2010 Subaru that had a brake caliper that was hanging up. While this rotor was hotter than the rest it's the heat distributuion on the rotor that caused me to stop and think. What's going on here ? You would think that the hottest part of the rotor would be the friction surface but the camera show the heat to be concentrated on the hub and the fins. Two thoughts come to mind. First, this is the way the rotors are supposed to work, drawing the heat away from the friction surface. Or, it's the nature of thermo cameras. The friction surface has a more reflective surface and the camera has a harder time measuring the true temperature. ???? More experimentation is in order I think.
                      Heat definitely transfers. There isn't any air passing over the hub area to cool it. The fins in the rotor are supposed to be designed to move air (some have curling in the fins to promote this) but when stationary, there isn't any air moving. The flat pad contact area is a larger surface than the fins and is more exposed.
                      Initially when the pad is pressing against the rotor, that would be the hottest area, That flat exposed area may dissipate the surface heat pretty quickly. (watch a NASCAR rotor going into the corners at short tracks)
                      Definitely worth some more observations Bob.

                      Comment

                      • Witsend
                        Banned
                        • Nov 2012
                        • 2942

                        #26
                        If you are behind on your revolving account , your Snap On Dealer will find you.

                        Comment

                        • David Green
                          Senior Member
                          • Oct 2009
                          • 382

                          #27
                          Originally posted by Witsend
                          If you are behind on your revolving account , your Snap On Dealer will find you.

                          https://www.youtube.com/watch?v=OW1gGDbO_1U
                          Not find me LOL


                          Comment

                          • Tech_A
                            Senior Member
                            • Jul 2014
                            • 115

                            #28
                            Originally posted by greasybob
                            Hot rotors, this is from a 2010 Subaru that had a brake caliper that was hanging up. While this rotor was hotter than the rest it's the heat distributuion on the rotor that caused me to stop and think. What's going on here ? You would think that the hottest part of the rotor would be the friction surface but the camera show the heat to be concentrated on the hub and the fins. Two thoughts come to mind. First, this is the way the rotors are supposed to work, drawing the heat away from the friction surface. Or, it's the nature of thermo cameras. The friction surface has a more reflective surface and the camera has a harder time measuring the true temperature. ???? More experimentation is in order I think.
                            Refer to page 22 of the thermal imager manual "3.5.5 Emissivity" (https://www1.snapon.com/display/3871/DTI_UserManual.pdf) I had some issues getting accurate measurements on painted motorcycle engine components.

                            Comment

                            • greasybob
                              Senior Member
                              • May 2008
                              • 1590

                              #29
                              So I saw the Engineering Guys Video on the drinking bird (link below). The one remember from when I was a kid in the early seventies. The explanation on how it works is as follows. The bird head is covered in a felt type material. When dipped in the water this creates evaporation which cools the head which then causes a pressure differential in the gasses inside the bird which then causes the liquid to rise to the birds head which then tips again into the water which allows the liquid to return to the base and the process repeats. Closest thing to perpetual motion as you will get. So I thought I would check the theory with my thermal imager. It seems correct. you can see the temp difference even after the bird and the water have been sitting at room temperature all day. https://www.youtube.com/watch?v=UCKC-QVcVn0&t=331s
                              Attached Files

                              Comment

                              • greasybob
                                Senior Member
                                • May 2008
                                • 1590

                                #30
                                I've been playing with these addressable L.E.D. light strips. Pretty cool. Each LED has a red, green ,blue LED and it's own chip so each led is controlled individually. Just three wires for the strip, 5V, ground and a communication wire. I control it with an Arduino which can be programmed from a laptop. You can make all kinds of cascading patterns. It uses a NRZ communication which is incredibly fast as seen in the scope shots. I even hacked one of my Snap ON 5volt USB chargers for a power supply.
                                Attached Files

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