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MPI MAXX #MCC345 Cermack 1.6 / 2.1) Gearbox

May 5, 2003 Update: Note the Current Gearboxes come with 3 pinions for 2:1, 2.5:1 and 3:1 Ratio and can be purchased with either 2.3mm bore or 1/8" bore pinons

Setup Speed 400 / Dymond MAX 48 Recommendations and test results;

By Irv Cooper: Revised 5/3/99

May 5, 2003 Update:  NOTE: This article has been pretty much obsoleted as all of the new MPI Maxx gearboxs come with the ball bearings and the gear reversed.  However, it is still an absolute must to add the CA or Loctite to the screws that hold the whole thing together.  See 5/3/99 Revision below.

• If you do not buy them with the ball bearings, put the ball bearings in yourself (The bushing version is very ineffiencent unless you lubricate them for every use)
  
• If you decide to run them without ball bearings - re lubricate every run. It makes about a 15% difference in efficiency. Plus those little bushings do not hold up more than a couple of runs without fresh lube each time.  Particularly make sure you get some in the bushings and on the thrust faces of the bushings.  I have found the spray lithium grease works pretty good and is easy to use.

• 5/3/99 Revision - The little phillips head screws on each side that hold the gear box together have a tendency to work loose.  This puts undue stress on the bushings and the gears.  I recommend that you remove the screws and add a dab of locktite or slow set ca and reassemble (One screw at a time)
  
• Reverse the gears so that there was not so much cantilevered load on the motor shaft and so that the
  load was shared better on the output shaft bushings.I did not tach it, but thrust went up and amps went
  down for this change also.

Out of the Package Configuration	As Modified

• If possible use a collet prop mount directly on the output shaft and avoid using the prop adapter as it cuts way down on the cantilevered loads on the output shaft and propeller side bushing or bearing.  This also allows you to use the ground flat on the shaft to hold the output gear instead of the propeller adapter.

• Balance your propellers - especially if you are using the bushings -- a little vibration makes very quick work of the
  bushed model.
  
  My test numbers using the Bushing Setup (Freshly charged battery pack each time)
  
  Out of the bag bushed 9X7 Folder 8x800ar's Dymond MAX 48 Motor
  Thrust 12 5/8 oz Amps 13.9 Amps (Only 1 run)
  
  Still bushed, but reversed gears and lubricated bushings, gears
  and thrust areas every time.
  Av Thrust 19 1/2 oz Av Amps 12.3