Race Prep on my Crew Hull

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  • longballlumber
    Fast Electric Addict!
    • Apr 2007
    • 3132

    #31
    Alright Gang,

    Now that I am back from travel for work, I can give you some info on a couple of runs I did on my MC.

    For starters, both runs were on 4S2P 4200’s. The strut was set to the factory settings and never changed.

    I started with an Octura X440/3, this is the same prop that I ran on the prototype version of the MC all summer last year. I knew starting with prop what to expect. On this run I ran the boat for just over 5min. It was long than I thought and I WOULD NOT advise someone to run their MC this long with the X440/3. The batteries, motor, and controller came in hotter than I like at low 120’s. I prefer to keep things under 110*. The boat was running rock solid. The wind was pretty gusts nearing 20mph. I honestly expected to boat to be loose and flighty, but it never happen. Even when driving into a head wind. I am still working with the Eagle Tree System, so I am not going to post my graphs until they are visibly easier to read. On this run I was pulling in the upper 60 amp rage with a mid to low 40’s speed. Remember this speed was maintained over 5+ minutes. Towards the end of the run I was trying to get the boat to roll onto itself, buy doing an extremely tight and elongated figure 8. The only thing the boat did was spin out once. Otherwise, it would handle the tight turns and instant acceleration fine. I was surprised and happy all at the same time. Oh yeah, I forgot the battery position on this run. I ran the packs as far forward as possible, up to the motor mount.

    The second run was with an ABC 45X55 (similar to the GrimRacer 42X55 only a tad larger diameter). I also moved the CG of the boat back by .75” from the first run by moving the batteries back in the boat. This run was just over 3 minutes. The boat was running a little lighter and with a little more speed. Even though this run the boat was running a little more lose, it didn’t have any indication of blowing off. I expect that I will be running this prop for Offshore heat racing. Temps were still a little higher than I like, but I feel that some prop work will help this. This 45X55 prop can be thinned and sharpened a little better. I may even remove some of the tongue. The temp on the motor and controller were in the low 120’s again, and the batteries were low 110’s. The speed increased slightly into the mid to high 40’s (47 mph max). My amp draw did go up slightly into the low 70’s.

    I am really pleased with the first two runs. I have some work to do getting the temps and the amp draw a little lower.

    Have Fun
    Mike

    Comment

    • hobby_man
      Senior Member
      • Sep 2011
      • 103

      #32
      what was the stock mph vs the modified boat mph?

      Comment

      • longballlumber
        Fast Electric Addict!
        • Apr 2007
        • 3132

        #33
        Hello,

        I wouldn’t necessary consider the boat “modified”. I would consider everything listed in this thread (besides replacing the flex shaft) a fundamental of getting a RTR boat TRULY ready to run. All of the information provided doesn’t necessarily provide a performance advantage as much as it lets you learn about the boat and makes sure everything fits correctly providing an enjoyable time at the pond.

        Back to your question; I never ran the boat before creating this thread and going thru the entire boat.

        Later,
        Mike

        Comment

        • justski
          Senior Member
          • Sep 2012
          • 230

          #34
          thank you very very much for this thread best i read so far ....

          Comment

          • pistol18
            Senior Member
            • Sep 2012
            • 248

            #35
            Great thread, thanks for all the info and pics!!

            I just picked up a used MC and it has the following eqipment:

            seamonster 2300 kv motor
            seaking 120esc
            octura x438 prop
            flipped motor mount
            hyperion v3 4s 4200mah 35c single batt mounted across the back of hull between servo and esc

            Boat runs decent(I'm coming from a rio 51 that was much bigger and ran 48 on gps for reference)
            but does seem slow to get on plane. Turns on a dime though, wow!
            I've read the grim 42x55 prop is a good choice for this hull, should I swap to that?

            For the drive cable, I'm not sure if its stock or upgraded but will prob get the ose upgraded shaft when its back in stock.
            Also, I don't see the bushing in the drive strut when I took the cable out to lube it? guess it was removed by prev owner?

            Thanks in advance for the help!
            Joe

            Comment

            • pistol18
              Senior Member
              • Sep 2012
              • 248

              #36
              Anyone????

              Comment

              • Grimracer
                Senior Member
                • Nov 2008
                • 662

                #37
                I suspect the reason we are slow to react is your setup and what the boat came with.. It would be a guess (edgamcated guess ) but a guess none the less to (make you go faster?)

                The first thing I would do is start over and from the basics.

                Grim

                Comment

                • hobby_man
                  Senior Member
                  • Sep 2011
                  • 103

                  #38
                  Originally posted by pistol18
                  Anyone????
                  what is the question?

                  My new MC stock went 34 mph out of the box.
                  I installed the Grim 42x55, re aligned a few things now its at 42 mph.
                  Lipo's are traxxas 2s 10000 mah, they weigh 1 lb each

                  To get my boat to go faster? Lighter Lipos will help for a mile or two, I have some on the way. Other than that 42 mph out of this boat is real good.

                  SPEED cost MONEY!

                  Comment

                  • pistol18
                    Senior Member
                    • Sep 2012
                    • 248

                    #39
                    Thanks for the replies! Please go here next:

                    http://forums.offshoreelectrics.com/...after-esc-fire!

                    Comment

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