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RADIO GEAR

While we are talking about radio gear,  to protect the receiver and servos   I  cover the control board with silicon grease,  silicon sealant or candle  wax! How many of you just passed out? If ever my radio gear  gets  wet   for  whatever  reason,  which is more often than I would like, the coating  helps  to  protect it from corrosion.   If you do suffer from  a  ducking,  switch off the receiver in the boat as soon as possible and disconnect the  batteries.  When you get home, strip down and wash out all the radio  gear  with  clean water.  Blow or shake dry as much as possible and leave to dry  on  top  of  the hot water tank or radiator and you should be  OK.  If  it  doesn't work when you try it again,  check for corrosion,  particularly on  the negative side of the circuit.  Repair as and where possible.  Also try  scrubbing  the  circuit  board off with a safety solvent or  meths  and  a  toothbrush.   Now lubricate  all  the  working  parts and reassembled.  If  you  are  going  to  be   brave   and   coat the  insides  of  your  radio  equipment  then do so only if you're  fairly  confident  about  doing  so.  Be careful not to get any in  the   servo  motors   and control 'pot'   as  you  should use switch   cleaner/lubricant  spray in these.  Don't mix any  silicon  grease,  switch  cleaner  or solvent as they are  not  compatible  although all three are needed when repairing a servo. Apply each carefully  and  precisely.  Never  use spray lubricants such as WD 40 etc.  as  these  leave  a  sticky  residue.  I  must stress however  that  all  this  extra  protection  is 'belt & braces'  or a 'last hope'  procedure and voids  any  manufactures guarantees.  Most servo don't need anything more than a water  proof box for protection.

    Nearly all servos and ESC's will work with any receiver as long as you can  find a plug that fits it.  If you are in any doubt don't chance  anything,   ask someone who knows, there is always someone in the local  boat club. If  you  can't find anyone to help,  you could try the local model shop but he  will  probably  try to a whole new set of radio gear so take  your  cheque  book with you.  Don't attempt anything you are unsure about  and of course  don't do any work on any circuit with the power or batteries connected.
 
UPGRADING YOUR ELECTRIC SPORTS BOAT.

   Right that everything covered,  motors, batteries, circuits, wiring, speed  controllers and radio gear that should get your boat going. Once your boat  is  going there are a few things we can do to make it go faster.  How much  faster you want the boat to depends on how much money and time you want to  spend on it.    
What you can do are in order of price;

1)   Try a range of plastic props. 
2)   Upgrade the wire and connections. 
3)   Buy  specialist metal props, the maker will recommend the best sizes. 
4)   Upgrade your cells or cell type. 
5)   Install more cells. 
6)   Buy a higher revving motor. 
7)   Buy a bigger sized motor.   
8)   Upgrade the running gear, eg, flexi shafts & ball-race gear boxes etc    


   Options 5,6 & 7 may also need an upgrade of speed controller to handle the  extra  power.  Upgrading  the speed controller rarely increases speed  and  fitting  an  ESC  instead of a good mechanical one might  actually  reduce  speed.  Ideally  the lowest voltage loss is achieved by running   straight  wires  from the cells to the motor,  the more components and interruptions  to  this  chain  causes  unnecessary voltage loss.  An ESC has  a  lot  of  components  in it so can cause significant losses if you don't have a good  one.  In  my Scarab,  I've used a Robbe Rokraft 100 FET BEC electronic  speed  controller,  I measured I loss of over 1v from 7.2v cell packs,  a loss of  nearly  14%.  Some  of the latest breed of FET ESC  boast  inconsequential  voltage loss but these do not come cheap.

Upgrading in order of amount of work;    

1)   Make sure the hull and running gear is perfectly clean and polished. 
2)   Correct or adjust the centre-of-gravity. 
3)   Improve motor/prop shaft alignment. 
4)   Install race quality running gear. 
5)   Install an adjustable flexi shaft. 
6)   Install surface drive. 
7)   Install a gear reduction. 
8)   Re-shape the hull. 

   Water  cooling  can  be installed but it won't make your boat  go  faster,  it'll  just  stop your overloaded motor burning up!  Some or all of  these  improvements  may be required in order to get your boat really moving  but  on  some  boats it's just not meant to be.  Some boats will never ever  be  race  winners  either  because  of poor design  or  because  they  weren't  anticipated as race winners. Don't be fooled, spending a lot of money on a  boat  may  not  necessarily make it go faster.  Try to work out  what  the  problem actually is before getting out a bank loan. It may be something as  silly  as a speed controller not switching to full power or tight  running  gear.

    Fitting  larger props to your boat you will make it go faster because  the  motor  is made to work harder.  The motor is actually spinning slower  and  therefore  running  less efficiently.  Electric motors,  like  IC  engines  deliver  their greatest amount of power and at high revs.  Your choice  of  size and pitch of propeller must allow the motor to 'unload'  i.e. let the  motor  rev  at it's most efficient speed.  A smaller or shallower  pitched  prop will reduce speed but improve run time significantly whereas a larger  or  high  pitch prop will increase speed but reduce run time.  Speed  will  always  be a compromise and each modeller must ascertain what he wants the  boat to do.

    My  usual  route of upgrading is to first try various  props,  adjust  the  running  gear and then try different motors.  If all else fails I put  the  boat aside until inspiration strikes or I see another modeller with a good  idea  and  copy  that!   The  following  review  articles  will  show  the  development path for each boat.
 
Epilogue

  And that's about all I want to say on electric power, if you have any  comments,  corrections  questions or I've missed something out altogether,  then email in and I'll ask somebody that knows what they are talking about!

N.B.  In   "IN   DEPTH",   the  magazine  produced by  the  Association  of  Model  Submariners  (AMS)  it  has  been  discovered  that  it's not  electricity  but  smoke that make electronic circuits work.  If  you allow the smoke to  escape   from  the circuit,  it ceases to function.  The smoke customarily  escapes  with  a visible and audible warning in the form of  an  expensive  flash and bang  before you can switch it off. The AMS is currently seeking   government  funding  for  further   research  into  this  phenomenon.  The  research is to be carried out in  the 'Submariners arms'  with the help of  generous  amounts  of  hangover fluid to keep the brains lubricated.


     The drawback of fast electric boats is the lack of run time, 10 minutes in  a  fast  electric is VERY good.  Even though they are simple and clean  to  operate there is no substitute for raw power. In model boats we turn to IC  engines  to make our boats really move and the run time is only limited to  the size of the fuel tank. IC ENGINES.

 Well  all  of this is just my opinion,  but what the hell do I know!
 

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