real time dyno?

[Michael T. Kasimirsky]

On Mon, 26 Aug 1996, Michael D. Porter wrote:

> wmcgonegal at rr.etc.ncr.doe.ca wrote:
> 
> > 
> > If you can manage to put a strain gage on you drive shaft and get it
> > calibrated, ....  Of
> > course, constructing and calibrating such a monster is not a trivial
> > task.
> 
> Will makes a good point which has plagued me over the years... how does 
> one go about calibrating a home-made dyno?  To some degree, a 
> strain-gauge sensor has some attraction, since its resistance change with 
> strain is a known quantity, but one must still be able to equate that 
> strain to torque, which depends on the mechanism and the position of the 
> strain gauge.  And while there may effective ways to absorb power by 
> other means, the measurement of the absorbed power still seems devilish. 
> Any ideas on means, or does anyone have knowledge of how the commercial 
> dyno manufacturers do calibration?
> Cheers. 

A dyno is typically calibrated by hanging dead weights from a moment arm 
built into the dyno housing.  The length of the arm is known, so the 
torque load is known.  This is used to calibrate the load cell readout.  
Horsepower is then mathematically calculated from the torque value.

Michael T. Kasimirsky       ---->              mtk at tmc.astm.cmri.cmu.edu
Days:    Staff Engineer                     or mk4u at andrew.cmu.edu
         ASTM Test Monitoring Center		Phi Gamma Delta,
Nights:  1992 Suzuki GSX-R750 Pilot		NRA Life Member, AMA Member
         1991 Suzuki GSF400 Bandit Mechanic	DoD #1848