Propellers Suck

Hamilton Standard propeller on Douglas DC-3 Photo: By Z22 - Own work, CC BY-SA 4.0

No, I'm not being nasty - I’m just finishing up studying the material for the FAA's A&P Powerplant knowledge exam, and finding out all sorts of interesting things that the FAA wants me to know about propellers. Interestingly, some of them are actually true!  Well, truth is sometimes a matter of which vocabulary you are using, but when it comes to an FAA knowledge test, theirs is the only one that counts! Continue reading "Propellers Suck"

Prop War?

Whirlwind composite prop on David Sterling’s Lancair
This Whirlwind composite on David Sterling’s Lancair is the latest go-fast prop in the Reno Sport Gold pits.

For years Hartzell has ruled the roost in Sport class racing around the pylons at Reno. Their "race prop," as it’s universally called, has been found faithfully propelling nearly every front runner Glasair and Lancair for over a decade and it’s responded well as race speeds have steadily climbed. Continue reading "Prop War?"

Test Mule PSRU

Test mule prop speed reduction unit (PSRU)

Here's an interesting idea, a test mule propeller speed reduction unit. A very wide belt tension adjustment range allows the installation of almost any drive pulley diameter, thus many different reduction ratios (and matching propellers) can be test flown without major modification. Continue reading "Test Mule PSRU"


Even though I understand and am a big fan of dynamic power plant balancing, it never ceases to amaze how much difference it can make in an airplane that you have gotten used to before it is balanced - or rebalanced. Generally speaking, once you've done a good job of dynamic balancing, the airplane should stay smooth until something changes - a prop removal or overhaul, significant engine work, or a prop leading edge cleanup. But things wear and change gradually over time, and the slight change in balance goes un-noticed as the airplane just reverts to what we'd call "factory roughness" - the amount of imbalance that is acceptable for a mass production job, but that just isn't quite as good as it could be.

Dynavibe RV-3

Continue reading "Smooooth!"

Whirlwind Visit

Whirlwind propellers

Gillespie Field in El Cajon, California is an interesting place for experimental aviators. With no signs to tell you what's in a row if tall T-hangars on the southeast side, you'd never know that it is home to a number of key manufacturers in our industry. I'll only mention one today - Whirlwind Propellers, a maker of composite props for aircraft, airboats, and anything else that needs a blade to move air. We dropped in on the owner and founder, Jim Rust to find out how they design and build their wide variety of props. Continue reading "Whirlwind Visit"

Nose Job

There comes a time in every plane's life when you just have to take her down for maintenance. Our RV-3B is probably the most delightful airplane I have flown, and I hate to leave her on the ground for any length of time - but we must salute the rules of preventive maintenance, and in this case its time to send the prop in for a little checkup.

Prop overhaul

Continue reading "Nose Job"