Dumas 1/8th scale nitro conversion

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  • crabstick
    Senior Member
    • Jul 2008
    • 954

    #31
    Valium anyone?

    Originally posted by Xfactor
    What size prop you run on it? Whats your rpm range?
    Still tuning the RCMK, no rev counter at the moment, but have been trying a heavilly cupped X467 , a 1470, and an ABC MW3..

    I have had to de-butcher the boat from the last owner, motor mounts were crooked and too far forward and it ran a bit like a plow in calm water.. Now the motor is back an inch and the radio box is back an inch, it gets up and dances..

    This weekend will hopefully finish the tune with the alloy pipe, then once I finish the muffler for my QD hotpipe we should see a few more mph..
    Matt.
    FE, Nitro and Gas racing in Auckland
    www.rcboats.co.nz

    Comment

    • Xfactor
      Banned
      • Mar 2009
      • 861

      #32
      I gotta do some work on this boat. Well I need some big bullets for the screamer . I dont know what size. 8mm I guess. I need an alternative to deans plugs too. Anyone?I also am goind to start working on the canards. Once I get the m,echanics worked out ill re install the microcontroller and start on some code.I think I will keep it simple and make an optical shudder on the rudder arm and have the stamp slowly add downforce in a right turn. Ill also make a shudder wheel and mount it to the back of the screamer for shaft speed via and optical shudder. Ive been thinking about what kind of hardware items i will need to measure the amps. I need a shunt of some type. I guess while Im at it . I may as well look to add a automated cooling system with a water pump and fans.I can use an old winshield wiper fluid pump for that.This basic stamp is memory limited so a graphic lcd is a bit much. I could add a alphanumeric display like you see in the typical watt meters but that too would require a decoder chip to handle the cgmap with this stamp so i choose to use some 7 segment displays . Thay are good to display numbers and simple words or abbreviations.

      Comment

      • crabstick
        Senior Member
        • Jul 2008
        • 954

        #33
        so much technology going into that bad boy that you might have to name it starship enterprise

        Will be an interesting project though something I wouldn't attempt myself. for racing for me it needs to have minimal moving parts for less things to break, you going to race this beast or sport run?
        Matt.
        FE, Nitro and Gas racing in Auckland
        www.rcboats.co.nz

        Comment

        • Xfactor
          Banned
          • Mar 2009
          • 861

          #34
          Lol. Its not really anymore than anyone else this is just whats involved in the consumer electronics everyone buys. It might all go poof but we will learn from it. I hope the canards and active surfaces manifest into something we can all gain speed from.Its just a boat nothing special.Sport for now.

          Comment

          • crabstick
            Senior Member
            • Jul 2008
            • 954

            #35
            dont get me wrong I like what you are doing, Im not dissin ya or nothing, more power to ya, if no one thought outside the box it would be a very boring world in deed Cannards are an excellent idea, I think if you set them up with an AVCS Gyro like a GY240 or GY401 futaba, and a fast digital servo they might be quite useful,.I have seen a pad on the right rear of a naviga style mono that comes down in right turns to stop the boat rolling over, i think that was an aircraft radio with a mix setup on right rudder input.
            Matt.
            FE, Nitro and Gas racing in Auckland
            www.rcboats.co.nz

            Comment

            • Xfactor
              Banned
              • Mar 2009
              • 861

              #36
              No I dont think youre dissing me crab it is alot of stuff.I just wanted to experiment. I mean I can just go with what works and run the boat. Then wat?Fun is over and ill be building another boat,So i wanted to take some time with my scale and try things ive been thinking about for years.

              Comment

              • Xfactor
                Banned
                • Mar 2009
                • 861

                #37
                Racing an 1/8th scale scares me anyway. So much time put into the paint,detail, and all you know what Im sayin?To race mine I have to be confident in the other drivers not to run my boat over. Theres a way around that huh? HAVE THE FASTEST BOAT lol.That would be hard with some of the guys on here to compete against.I mean look at people like randy you cant touch all that experience . Mark F and his 80/90 mph hydros thees guys are cooking.Thers no doubt that there are some people on here id just love to sit and pick their brains.

                Comment

                • Xfactor
                  Banned
                  • Mar 2009
                  • 861

                  #38
                  Steve Look for my order. I need some big bullets for the screamer and some type of alternative for the deans plugs . I also need a cooler for my kb.

                  Comment

                  • Xfactor
                    Banned
                    • Mar 2009
                    • 861

                    #39
                    Hey I actually managed to get some things done today. I made the optical trigger wheel for the screamer.Check it out. The small circuit in the photo is the optical shudder that will send the signal to the microcontroller . I plan to impliment closed loop simply by having the microcontroller act as and active bypass between the rx and the esc;modifiying the signal coming to the esc from the reciever if it senses slip.If youi had a schultz with hall option then you could make a wheel like this out of oh well let me shut up.
                    Attached Files
                    Last edited by Xfactor; 05-21-2010, 08:17 PM.

                    Comment

                    • Xfactor
                      Banned
                      • Mar 2009
                      • 861

                      #40
                      I made an esc plate . I will also mount the optical shudder to this plate.
                      Attached Files
                      Last edited by Xfactor; 05-23-2010, 11:09 AM.

                      Comment

                      • BHChieftain
                        Fast Electric Addict
                        • Nov 2009
                        • 1969

                        #41
                        Originally posted by Xfactor
                        Hey I actually managed to get some things done today. I made the optical trigger wheel for the screamer.Check it out. The small circuit in the photo is the optical shudder that will send the signal to the microcontroller . I plan to impliment closed loop simply by having the microcontroller act as and active bypass between the rx and the esc;modifiying the signal coming to the esc from the reciever if it senses slip.If youi had a schultz with hall option then you could make a wheel like this out of oh well let me shut up.
                        What does the optical trigger wheel do?

                        Chief

                        Comment

                        • Xfactor
                          Banned
                          • Mar 2009
                          • 861

                          #42
                          It breaks the beam between photo emitter/collector circuit (shudder) which will send hi 5volt pulses to the microcontroller. Then through the appropriate code the microcontroller will know the motor shaft/prop position throughout its rotation.It basically turned a sensorless motor into a sensored motor which theorhetically will have many benefits over the typical sensorless setups we run.

                          Comment

                          • BHChieftain
                            Fast Electric Addict
                            • Nov 2009
                            • 1969

                            #43
                            Originally posted by Xfactor
                            It breaks the beam between photo emitter/collector circuit (shudder) which will send hi 5volt pulses to the microcontroller. Then through the appropriate code the microcontroller will know the motor shaft/prop position throughout its rotation.It basically turned a sensorless motor into a sensored motor which theorhetically will have many benefits over the typical sensorless setups we run.
                            Did you design a custom esc?
                            Chief

                            Comment

                            • Xfactor
                              Banned
                              • Mar 2009
                              • 861

                              #44
                              The esc is in the works but what i plan to do for rite now is run this microcontroller board (which already has crude datalogging via serial to the pc) as a active bypass between my rx and turnigy esc.As far as my esc i am selecting drivers,mosfets, and a brain to run it all. The brain will possibly be the parallax propeller chip, or an 18 series pic or a pic in the dsp family . I ll have to do some mathematical calculations to select the right drivers, as well as the right capacitors and resistors in the RC circuits for the right rise and fall time of the mosfets which is dictated by the pole count and stator arms as well as the max rpm for the motor. It will take awhile its do-able though. I also intend on letting the proposed microprocessor run on board graphic display with a directional keypad as well as telemetics via 2.4ghz.It will have a menu and programming would be accomplished through navigation of on screen GUI. If I knew the type of hall sensors a shultz wanted I could easily modify this for their esc. All the firmware is already there for the shultz. I dont know what the closed loop function on a shultz will offer u though outside of the obvious benefits of a closed loop design.One of u owners of one will have to school me on that.To accomplish the bypass i may need another piece of diy hardware: a servo pulse to pwm module.
                              Attached Files
                              Last edited by Xfactor; 05-23-2010, 09:15 AM.

                              Comment

                              • Xfactor
                                Banned
                                • Mar 2009
                                • 861

                                #45
                                Canard servo mount finished.
                                Attached Files

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