Impulse 31 bouncing baby boy

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Skullcracken
    Senior Member
    • May 2010
    • 617

    #1

    Impulse 31 bouncing baby boy

    I know guys have already commented on this but crap. I have adjusted the COG, I've adjusted the strut - what helps this thing's bouncing. I wouldn't call it porpoising, it pops up out of the water fully , instead of bobbing up and down at the front like when boats porpoise. I've seen vids with this thing glued to the water. Can't figure out how to keep it down.
  • roadrashracing
    Fast Electric Addict!
    • Aug 2010
    • 1462

    #2
    On mine I found the best way it ran at higher speeds was the trim tabs just bent down a little, bit.

    Comment

    • Darin Jordan
      Fast Electric Addict!
      • Apr 2007
      • 8335

      #3
      What prop are you running??

      At certain speeds, it gets to the point where the lift of the hull is too much for the power. When you hit that point, the solution is to add weight to the centerline on the CG... When I run mine in P-Mono, I run 4S2P and an additional 6-12oz of weight added under the battery tray or just aft of the motor.
      Darin E. Jordan - Renton, WA
      "Self-proclaimed skill-less leader in the hobby."

      Comment

      • Bullwink
        Senior Member
        • Oct 2011
        • 244

        #4
        Darin what prop are you running in P-Mono?

        Comment

        • Darin Jordan
          Fast Electric Addict!
          • Apr 2007
          • 8335

          #5
          Originally posted by Bullwink
          Darin what prop are you running in P-Mono?
          That's not a safe question for me to answer at this point.... Thus far, I've been playing with motors and most of what I currently have has been way too "hot" for an actual P-Mono setup.

          The one setup I used that does work is the Losi Xcelorin 1/8th scale buggy motor @ 2100KV. Nice motor. 4-Pole, has HUGE 8mm shaft, turned down to 5mm, so solid bearing setup. With this motor, I was running an X447/3 and having decent results.

          Again, I'm still playing with these setups and certainly don't have all the answers for the higher power stuff in this hull. Like I mentioned before, it's designed for P-Ltd power and to work well in the power range. When you start adding more power, you'll need to add some weight as some point.
          Darin E. Jordan - Renton, WA
          "Self-proclaimed skill-less leader in the hobby."

          Comment

          • Skullcracken
            Senior Member
            • May 2010
            • 617

            #6
            First just tinkering with it stock everything. Bounces on 4s and 5s. I have a leopard 2200kv on the way. I've bent the trim tabs down some, but I didn't want to over do it and kill speed with drag. I've moved the lipos forward and adjusted the strut positive. Trying negative initially made it worst. Don't know. In any turn, slight or hard, doesn't bounce at all.

            Comment

            • Skullcracken
              Senior Member
              • May 2010
              • 617

              #7
              Originally posted by Darin Jordan
              That's not a safe question for me to answer at this point.... Thus far, I've been playing with motors and most of what I currently have has been way too "hot" for an actual P-Mono setup.

              The one setup I used that does work is the Losi Xcelorin 1/8th scale buggy motor @ 2100KV. Nice motor. 4-Pole, has HUGE 8mm shaft, turned down to 5mm, so solid bearing setup. With this motor, I was running an X447/3 and having decent results.

              Again, I'm still playing with these setups and certainly don't have all the answers for the higher power stuff in this hull. Like I mentioned before, it's designed for P-Ltd power and to work well in the power range. When you start adding more power, you'll need to add some weight as some point.
              How are you increasing prop size? Did you change out the rudder assembly? In a full left turn, my 40mm prop is very close to the rudder, and a 42mm nearly touches the rudder. (Bench tested)
              Last edited by Skullcracken; 02-28-2012, 08:54 PM.

              Comment

              • de-pro
                Senior Member
                • Aug 2011
                • 180

                #8
                it shouldnt be. this is a 447 prop in the picture

                DSCN0667 (1024x768).jpg

                Comment

                • de-pro
                  Senior Member
                  • Aug 2011
                  • 180

                  #9
                  it shouldnt be. this is a 447 prop in the picture

                  DSCN0667 (1024x768).jpg
                  DSCN0677.jpg

                  Comment

                  • stadiumyamaha
                    Fast Electric Addict!
                    • Apr 2011
                    • 1284

                    #10
                    It depends on your steering rate. I have to turn mine down when running a larger prop. Found out the hard way too.
                    white geico w/2200kv 3674 leopard 53.5mph 4s2p, geico w/ 1800kv outrunner 52mph on 4s2p, genesis w/2200kv castle 53.8 on 4s2p, impulse 31 w/2200kv castle, stock p1 and ul-1

                    Comment

                    • Skullcracken
                      Senior Member
                      • May 2010
                      • 617

                      #11
                      [QUOTE=de-pro;395817]it shouldnt be. this is a 447 prop in the picture

                      Have you rotated the prop so the blades are horizontal and turned the rudder fully left and looked? This is the stock 40mm prop, probably only about 3mm's from touching the rudder... Looks like I could only go up to a 42mm prop, unless I sacrifice turn endpoints and lose maneuverability.
                      2012-02-26_23-03-09_85.jpg

                      Comment

                      • Skullcracken
                        Senior Member
                        • May 2010
                        • 617

                        #12
                        Originally posted by stadiumyamaha
                        It depends on your steering rate. I have to turn mine down when running a larger prop. Found out the hard way too.
                        Posted before I saw your reply. Thats what I figured. Don't know how that guy is using a 47mm prop though. I don't want a 30ft turn radius...

                        Comment

                        • Skullcracken
                          Senior Member
                          • May 2010
                          • 617

                          #13
                          Fixed the bouncing. I increased the positive on the strut, and bent the trim tabs to the point where they are level with the bottom of the hull but mounted a couple of mm's higher than the bottom. (meaning bottom of the hull relative to the location of the mounts - obviously not the actual bottom at the apex of the "V" bottom) No more bounce but seems to be a good amount of drag. Noticeably slower.

                          Comment

                          • Skullcracken
                            Senior Member
                            • May 2010
                            • 617

                            #14
                            Originally posted by de-pro
                            it shouldnt be. this is a 447 prop in the picture

                            [ATTACH=CONFIG]71265[/ATTACH]
                            Actually looking at this angle, maybe the longer length of a bigger prop would extend the blades past the rudder?

                            Comment

                            • de-pro
                              Senior Member
                              • Aug 2011
                              • 180

                              #15
                              Steering rate at 100% and no it doesnt turn like a Mack truck :)
                              Here is some more photos

                              impulse prop 002.jpgimpulse prop 001.jpg

                              Comment

                              Working...