Thanks!

The Hs81-MG has a smaller casing compared with the Hs85-MG. The Hs81 has double ball bearings and metal gears, but produces a lower torque at 4,8v. The output torque is 2,6kg, and the 85-MG delivers 3,0kg torque.

Hitec Hs81-MG specs:
* Speed 0.11sec/60° at 4.8 volt.
* Torque 2,6kg * cm at 4.8 volt.
* Weight 16,6 gram
* 29,8x12x29,6mm (Width: 12mm instead of 13mm)
* Metal gears


Hitec Hs85-MG specs:
* Speed 0.16 sec/60° at 4.8 volt.
* Torque 3 kg * cm at 4.8 volt.
* Weight 19 gram
* 29x13x30 mm
* Metal gears

It should be fine. It has been used very often in Stiletto's and all other speedmodels from Corvidae / Jet & Speedmodels.