RCU Forums - View Single Post - 20t motor in a RS boat - slower than stock - why?
Old 10-31-2004, 11:34 PM
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gulfstreamI
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Default RE: 20t motor in a RS boat - slower than stock - why?

ORIGINAL: mocars2

GulfstreamI - how did the testing two other alternative electric motors for the Nikko & RS boats?
Mocars2,

Time to to dust off this topic. Cough! Cough!
As we already know: [ul][1] This boat's ABS hull in stock form is just too heavy for any speed.
[2] The stock ESC limits the performance of any motor ( 20 turn Traxxas or any 550 class motors)
[/ul]
What's been done so far:[ul][1] The hull has been lightened. All excess plastic covers & non-critical plastic removed.
[2] The stock electronics has been replaced with compact , lighter & more efficient units. This includes the E.S.C. receiver unit & steering servo. The electric bilge pump has also been removed.
[3] Water cooling is used only to cool down the electric motor.
[/ul]
The hull was lightened by:[ul][1] Shaving off excess plactic hull braces inside the hull & installing extra styrofoam floatation.
[2] The trailing edges , rudder are "sharpened" & bottom of the hull is sanded & shaved to help water break off easily.
[3] Excess plastic from hatch cover is removed/shaved. This includes replacing the stock driver figure with a light weight counterpart.
[/ul]
The replacement electronics include:[ul][1] Futaba MC 310 CB . Spec: 148 amp, 16 turn limit motor w/ reverse & 30 amp fuse protection.
[2] Futaba FP-R102GR 2 channel 27 Mhz AM receiver with BEC (battery eliminator circuit)
[3] Hi-Tec HS-402X steering servo.
[/ul]Total weight removed from boat is 1.12 pounds. (this includes all electronics)
Total weight of replacement electronic parts .260 pounds.
The result:[ul]
[1] better acceleration (top speed to be decided after further testing of props)
[2] Turns faster, but rudder is too small to to make accurate "high speed turns"
[3] more choices of props to test.
[/ul]
The props tested so far: 40 mm 1.4 pitch & 42 mm 1.5 pitch. ESC OK so far no overheating after a 5 minute run using 7 cells (8.4 volt) & a Graupner Speed 600 8.4 volt motor.
Next prop to be tested is a Octura 1740 (1.7 pitch X 40 mm) three blade made of berryllium copper.

Why am I modifying this particular boat? It's an old style hull similar to those made by Robbe back in 1979 & an airboat hull made by Graupner in 1987 called the "Fluppi". I just have no luck locating these two particular boats so this is the next best thing for me.


GulfstreamI
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