Simon Thomas
Senior Airman
CMI's SB is not mandatory for Part 91 ops.
It is an appropriate course of action, but it is not mandatory.
It is an appropriate course of action, but it is not mandatory.
Does Belly Landing in Propeller Plane wreck its Piston Engine?
- Thread starter gruad
- Start date
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FLYBOYJ
"THE GREAT GAZOO"
Correct but in this case there is an AD that makes this mandatory
FLYBOYJ
"THE GREAT GAZOO"
Well I'll stand corrected! It looks like only Lycoming engines are tied to an AD!!!
Yeah, but he's just devalued the aircraft with a half-arsed repair. I know I'd be extremely cautious about buying it.
cvairwerks
Staff Sergeant
Personally, I'd treat any a/c that I was looking at buying, as having a junk motor, if it had a prop strike and there was no tear down and inspection in the engine log. Done it before and would do it again.
Yep.
It amazes me that people will try to save their insurance company money by not getting this done. They seem to forget that the instant you have an accident, the plane belongs to the insurance company.
As one who has flown thousands of hours in civil and military a/c, most of them recips and mostly short (non-airline) duration. In addition, a lot of them have been test or ferry flights. I consider this emphasis on "power cut/idle power" or wooden vs metal prop to be worthless.
IMHO, and from personal experience, a sudden stoppage at ANY RPM is a sudden stoppage!!
One item not mentioned is bent conrods, common in radial engines, and often caused by stoppages under a starter due to hydraulic lock (oil seeping into lower cylinders) or backfires while starting. That big prop is a massive flywheel, and it transmits serious forces through complex gear trains and engine internals which are stressed for smooth, steady state running.
Bottom Line - Would you fly in a plane that was "probably OK"? We've all had an issue that had us pull our car to the side of the road. From dozens of experiences, the difference between that and a forced landing is many orders of magnitude of stress and seriousness.
IMHO, and from personal experience, a sudden stoppage at ANY RPM is a sudden stoppage!!
One item not mentioned is bent conrods, common in radial engines, and often caused by stoppages under a starter due to hydraulic lock (oil seeping into lower cylinders) or backfires while starting. That big prop is a massive flywheel, and it transmits serious forces through complex gear trains and engine internals which are stressed for smooth, steady state running.
Bottom Line - Would you fly in a plane that was "probably OK"? We've all had an issue that had us pull our car to the side of the road. From dozens of experiences, the difference between that and a forced landing is many orders of magnitude of stress and seriousness.
MIflyer
1st Lieutenant
The main reason for using composite wooden props on Spits and Seafires was that the small airframe could not handle the large prop used on aircraft such as the P-51, using much the same engine.
buffnut453
Captain
What does the composite wooden construction have to do with the size of the propeller?
The Spit had a 10ft 9in diameter prop compared to the Mustang's 11ft 2in diameter. Not sure 3in (1.5in per blade) would make that much difference in propeller construction.
Shortround6
Major General
Propeller design and construction was the province of witches
Hamilton Standard design team on afternoon break.
A number of text books were published to hide this fact but it was all camouflage.
An ideal propeller needed to take into account.
expected speed range of the airplane or the desired max speed.
expected altitude range of the airplane or the altitude band. (a good prop at 20,000ft is too big for good work at 500ft)
Horsepower of the engine.
RPM of the propeller.
Number of blades.
Probably a few other things, pitch of the propeller is part of the propeller rpm and speed of the aircraft (IAS) interaction.
And that is for a fixed pitch prop.
Variable pitch props are on another level.
Hamilton Standard design team on afternoon break.
A number of text books were published to hide this fact but it was all camouflage.
An ideal propeller needed to take into account.
expected speed range of the airplane or the desired max speed.
expected altitude range of the airplane or the altitude band. (a good prop at 20,000ft is too big for good work at 500ft)
Horsepower of the engine.
RPM of the propeller.
Number of blades.
Probably a few other things, pitch of the propeller is part of the propeller rpm and speed of the aircraft (IAS) interaction.
And that is for a fixed pitch prop.
Variable pitch props are on another level.
MIflyer
1st Lieutenant
WEIGHT! And 3 in makes a huge difference in props, especially that size. Aside from that, there is prop chord.
Short answer? Yes. If you belly land a piston aircraft with the engine on and the props spinning, you will suffer a sudden stoppage and the engine will be toast. I'm not saying it can't be rebuilt, but it will be toast initially.
In a belly landing sequence you cut the engine shortly before touchdown to minimize damage to the engine.
In a belly landing sequence you cut the engine shortly before touchdown to minimize damage to the engine.
Spitfires ended up with 5 blade and then contra props, they must be heavier?
Maybe if you don't have insurance.
Personally, I don't care how much the rebuild costs the insurance company, and whether or not you shut the engine down won't figure into the equation when they assess it for write-off or rebuild.
I was always taught that you fly the plane first, minimising damage like this shouldn't enter into the equation, and shutting the engine down removes the option to go-around.
I do not disagree. Fly the plane, fly the plane, fly the plane…
I would only shut the engine off if landing was 100% assured.
Otherwise, I agree with you completely.
Check your sources, Mlflyer. I only question whether it was the MAIN reason.
Duraluminum was in short supply in wartime England, and especially processing plants AND the massive energy required to handle ore or alloy electric furnaces. On the other hand, they were masters of woodworking, skills that evolved from their centuries of high quality ship building from river punts to fishing vessels of all types to commercial shipping and ships of the line.
Why waste a scarce alloy when wood was easily available, backed up by a mature industrial capability, and a just as good.
At the same time, note that both suitable wood and aluminum raw materials had to be imported.
We were told to keep everything as normal as possible, including which lever you pulled back in the flare.
To be honest, an idling engine doesn't put any more stress on than a windmilling engine does. I've been a party to more than a few tear-downs due to wheels-up landings, and there doesn't seem to be any correlation if the pilot has pulled the mixture or prop.
manta22
Banned
If the propellor strikes the ground, the crankshaft will need to be Magnaflux inspected.
That's the standard procedure. Unless the flange is out of true, then there's no point.
Shortround6
Major General
See post about witches
In addition to the diameter of the prop (think span) you have width of the blade, (think cord) and you have thickness of the blade (air foil and camber),
some blade shapes were easier to do with certain materials. Some Aluminum blades were solid, some were hollow, I can't remember if any big ones were steel (hollow and welded?)
Some blades were synthetic (?) and it is here that some of the WW II "wooden" propellers may belong. Unlike the older carved propellers (which were mostly laminated) they impregnated the wood with higher percentage of resins/glues for strength rather than just gluing the wooden slabs together.
See : Spitfire Propellers | Fly a Spitfire | Biggin Hill Heritage Hanagar
from that site
"Hydulignum, a high strength compressed birchwood laminate was the main wooden material used............."
We really have to get away from the "masters of woodworking, skills that evolved from their centuries of high quality ship building from river punts to fishing vessels of all types to commercial shipping and ships of the line" stuff when talking about high performance aircraft.
They evolved wooden construction, not from traditional skills, but using new methods and thinking about how to use wood or wooden fibers with modern glues and resins into molded and compressed parts.
Also see : Hydulignum props
The British were often forward thinking and hi-tech.
In addition to the diameter of the prop (think span) you have width of the blade, (think cord) and you have thickness of the blade (air foil and camber),
some blade shapes were easier to do with certain materials. Some Aluminum blades were solid, some were hollow, I can't remember if any big ones were steel (hollow and welded?)
Some blades were synthetic (?) and it is here that some of the WW II "wooden" propellers may belong. Unlike the older carved propellers (which were mostly laminated) they impregnated the wood with higher percentage of resins/glues for strength rather than just gluing the wooden slabs together.
See : Spitfire Propellers | Fly a Spitfire | Biggin Hill Heritage Hanagar
from that site
"Hydulignum, a high strength compressed birchwood laminate was the main wooden material used............."
We really have to get away from the "masters of woodworking, skills that evolved from their centuries of high quality ship building from river punts to fishing vessels of all types to commercial shipping and ships of the line" stuff when talking about high performance aircraft.
They evolved wooden construction, not from traditional skills, but using new methods and thinking about how to use wood or wooden fibers with modern glues and resins into molded and compressed parts.
Also see : Hydulignum props
The British were often forward thinking and hi-tech.
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