RCU Forums - View Single Post - MHZ Flash, Flipping
View Single Post
Old 07-31-2007 | 10:17 AM
  #30  
spicedcrab
Senior Member
 
Joined: Feb 2005
Posts: 297
Likes: 0
Received 0 Likes on 0 Posts
From: mountain city, TN
Default RE: MHZ Flash, Flipping

jan, thanks for posting the pics, they look great.

update, all the mods were a big help in getting the boat under control but i could not get full speed still. i started looking real close at what it was doing, i noticed that the boat would jump in and out of the water, even though it was staying flat and level now from the mods. as the boat was out of the water and returning to the water it would hit the water and launch right back out again. the prop wash seemed like it was over twice the speed of the boat every time it touched down. i figured well maybe my prop should be turning slower and closer to the desired speed of the boat, i figured worth a try. i put a 7XL in with a kv of 2380 instead of the 4000kv motor that i took out.

1st test, same prop (x437). very stable but too slow, no sign of any heat in esc or motor.

2nd test, 40mm carbon prop, faster, still stable, but still not yet to speed it was with the other motor before hopping starts.

3rd, 45mm getting a little faster, nothing warm yet

4th, 48mm looks really good, very stable no rocking, no skipping. not super fast but looks to be about the speed that it was starting to hop at when it had the other motor. i decided to get the gps from my wifes car and see what its doing. i got 43.6 mph (i wish that i would have used gps before i changed motors too so i could compare) i belive it was hitting about 50mph before, but it was out of control. being able to get 43 and stable with less rpm and more prop makes me think that maybe this setup will give me more speed than the other motor.

i dont have any bigger props, but im ordering some. the goal is to try and get over 50mph. im wondering if i will actully end up going to far the other way now (my prop was too small with the other setup, now it may be too big) im thinking it will take at least a x455 to hit 50, or a x648

im wondering if running a 55mm size prop is going to have a bad effect on this size boat since i feel like im already pushing it with the 48mm, or if i switch to more pitch (x648) that may also be bad, any thoughts?

i could always switch to 4cell lipos instead of 3cell so i dont have to run a huge prop, but that would take another big investment in lipos and i would have to disable the BEC, so i would 1st like to see if i can just run a real big prop on the 3cell setup that i have now.

thanks,
john