I saw this video and I think it's a good reminder of what can happen if you neglect to re-torque your wooden prop.
https://www.youtube.com/watch?v=2MEapiGMbxw
https://www.youtube.com/watch?v=2MEapiGMbxw
Maybe to keep the alternator working?I wonder why he waited to shut the motor off till after he landed.
Great job of SA and getting the airplane down to a convenient airport. Very calm for a truly "Oh Sh##" experience.
But now I'm curious about the how and why! I can see some wobble, wear, out of balance and track kind of bad stuff from not torqueing a wood prop annually but how does that cause a prop to "depart" the aircraft. Prop bolts that are safety wired should not back out ... ? The prop isn't going to shrink enough to actually have gaps between the prop plate and the prop .... or is it?
The assumption is that it didn't just shed the blades and the hub remained. Assuming the prop didn't just shred itself, how would it just "come off" ?? All of the bolts would have to back out which implies they had enough "counter force" (is that a technical term) to shear the safety wire(s) at the same time and then back out all at the same time so that the prop doesn't wobble enough to give you some indication that something is wrong. If only one bolt and the prop plate were left, it certainly would not have just idled very well with a swinging weight on the drive shaft. Wish I could see the tach on the dash... and the engine/airframe after they stopped moving.
I just don't know .... ? Anybody else ever actually had all the prop bolts back out and the prop just take a hike ?? What's the failure mode?
Bill
Great job of SA and getting the airplane down to a convenient airport. Very calm for a truly "Oh Sh##" experience.
But now I'm curious about the how and why! I can see some wobble, wear, out of balance and track kind of bad stuff from not torqueing a wood prop annually but how does that cause a prop to "depart" the aircraft. Prop bolts that are safety wired should not back out ... ? The prop isn't going to shrink enough to actually have gaps between the prop plate and the prop .... or is it?
The assumption is that it didn't just shed the blades and the hub remained. Assuming the prop didn't just shred itself, how would it just "come off" ?? All of the bolts would have to back out which implies they had enough "counter force" (is that a technical term) to shear the safety wire(s) at the same time and then back out all at the same time so that the prop doesn't wobble enough to give you some indication that something is wrong. If only one bolt and the prop plate were left, it certainly would not have just idled very well with a swinging weight on the drive shaft. Wish I could see the tach on the dash... and the engine/airframe after they stopped moving.
I just don't know .... ? Anybody else ever actually had all the prop bolts back out and the prop just take a hike ?? What's the failure mode?
Bill
reminded me of this prop departure vid...I was at an airshow as a kid (many many years ago) when a friend of the family was doing an aerobatic performance (I think it was a Citabria, but that may not be correct). Down the runway inverted, pull up (or, I guess, push up ) and roll wings upright and...whooosh!...the entire prop departed company with the plane. The pilot, an ex-fighter jock, managed his energy well and cranked her over and back around to the runway for a safe landing. An outstanding bit of airmanship.
Prop flew what to my young eyes looked like several hundred feet up, and landed in the middle of the field (fortunately, away from the crowd).
I was way too young to have the presence of mind later to ask him why it came off. But if he wasn't a hero in my youthful days of loving flight before, he was after that!
(ETA: I seem to recall quite some time after that that someone said the flange sheared off...but it was so long ago, I wouldn't swear to that).
I wonder why he waited to shut the motor off till after he landed.
I just don't know .... ? Anybody else ever actually had all the prop bolts back out and the prop just take a hike ?? What's the failure mode?
Bill