Coupling the Chiaphua & a variable Drill output

[Jeff Sharpe]

Our team is considering using a servo-switched 2-speed drill motor assembly coupled to a geared-down Chiaphua shaft via a direct sprocket/chain tie. We do not want to build an external transmission.
We would gear the Chiaphua down to about 440 rpm to match the drill rpm in low gear, in hopes of nearly doubling our low gear torque. In high gear the Chia motor would then be spinning at about 14000 rpm (2.4x its free load rpm) and so inhibiting locamotion to some extent. We're thinking back-current is not a problem, and that the drill motor probably has more than enough power for our high-speed tasks plus spinning the Chia at these high rpms.
What do you guys think? Is this dangerous? Do we need to bench test to see what kinds of resistance the Chia develops? Thanks for your insights! J#