TRW Hartzell Propeller Vu-Thru II Tachometer C-4670 Aircraft Tool w/ Case Manual Click here to purchase or contact the seller of this item on eBay
Current Price: 149.99 USD

TRW Hartzell Propeller Vu-Thru II Tachometer, Model C-4670, a specialized aviation tool used for measuring propeller RPM through optical “freeze” viewing.

This unit was manufactured in Piqua, Ohio by TRW Hartzell Propeller and is designed for aircraft maintenance, inspection, and calibration work. Tools like this were commonly used by mechanics to verify propeller speed without direct contact.

What makes this one stand out

• Includes original instruction sheet/manual

• Comes with original leather carrying case

• Clearly marked Model C-4670 (Vu-Thru II)

• Made in USA – quality aviation instrument

How it works

The Vu-Thru tachometer uses an optical viewing system with adjustable coarse and fine controls to visually “stop” propeller motion, allowing RPM measurement without physical contact.

Condition

• Good overall vintage condition with normal signs of use

• Body shows light scuffs and age-related wear

• Instruction sheet has creasing and discoloration from age

• Leather case included and intact

Testing / Functionality

• Untested (requires 9V battery; no testing performed)

• All dials and adjustment controls move smoothly

• Sold as-is due to inability to test

Important Notes

• Model: C-4670

• Also referred to as Vu-Thru II Tachometer

• Similar in function to other Hartzell Vu-Thru units (ex: D-4390)