Does Belly Landing in Propeller Plane wreck its Piston Engine?

[gruad]

Much is salvageable from Belly Landing in Propeller Plane in WW2. I believe there were many Frankenstein Lancaster s containing components from their crashed brethren.

But the articles always seem to refer to sections of the fuselage or systems from the planes. There does not seem to be mentions of the engines.

So I am thinking does the force of the hard stop of the propellor when the plane pancakes get transmitted into the engine, wrecking the bearings and twist the engine casing?

Would this vary according to whether this was an inline or a radial engine?

I dont know enough about engineering or know of the history of mechanical salvage, so I am hoping that the forum are able provide some answers.

As always thank you in anticipation of your answers.

 

[pbehn]

This is a good read on prop strikes. https://www.aopa.org/news-and-media/all-news/2007/november/01/two-dreaded-words

 

[cvairwerks]

Depends on a large number of factors, including power settings at the time of impact, angles, speeds and what it hits. Generally, the engine is a total wreck, but accessories can be salvaged.

 

[GrauGeist]

Lots of factors involved as mentioned, but the main focus is on the engine's bearings and internal components.
If the pilot reduced the throttle and feathered the prop(s), then the engine was idle, which would do little damage to the engine.
However, the prop striking the ground with the engine under load causes the drive-train to "back up" in a sense. In other words, all that energy that the engine is creating to turn the prop is suddenly stopped, causing the engine's torque and horsepower to try and find another way to transmit that power.
The result is damaged bearings, crankshaft, reduction gears, stressed engine case and so on - usually a total loss for the engine,

 

[WARSPITER]

Also can depend on the angle of landing determined mostly bu the centre of gravity and whether the nose is armoured..............?

 

[pbehn]

Also can depend on the angle of landing determined mostly bu the centre of gravity and whether the nose is armoured..............?

A very subtle trending towards the dark side of the forum, almost unnoticeable to many.

 

[FLYBOYJ]

Any prop strike usually results in at least an engine teardown and inspection, pbehn posted a good article on this for GA aircraft. Over the years manufacturers have become more restrictive on this and for the 2 major GA aircraft engine manufacturers, Lycoming and Continental, a tear down is mandatory. I also believe the FAA and other countries airworthiness authorities have mandatory airworthiness directives on this as well.

 

[pbehn]

The OP mentioned Lancasters, I think the engine parts from Lancasters that belly landed were evaluated to be put in Meteor tank engines.

 

[WARSPITER]

The OP mentioned Lancasters, I think the engine parts from Lancasters that belly landed were evaluated to be put in Meteor tank engines.

Yes that was common practice until production was sorted.

 

[FLYBOYJ]

The OP mentioned Lancasters, I think the engine parts from Lancasters that belly landed were evaluated to be put in Meteor tank engines.

That would be a great alternative - I seen a Cessna 172 have a prop strike which I thought was pretty bad. The owner did a run out inspection on the prop flange and replaced the propeller. He then flew the aircraft another 1000 hours (put 3000 hours total on the engine) before he decided to have it overhauled! This was all before the mandatory inspection from the manufacturer and airworthiness directive came into play.

 

[SaparotRob]

I haven't read the manual but wouldn't that stupid?

 

[gruad]

The OP mentioned Lancasters, I think the engine parts from Lancasters that belly landed were evaluated to be put in Meteor tank engines.

Wow! You are right. From wiki

Development started with the use of recovered Merlin engine parts from crashed aircraft. While unsuitable for re-use in aircraft, the Rolls-Royce chassis division had begun collecting and refurbishing them in the hope of finding a use. Robotham was approached by Henry Spurrier, of Leyland Mechanization and Aero, to ask about help with tank powerplants. Based on Spurrier's requirement, the first prototype Meteor engine (and subsequent production of Mark 1 engines) was assembled on the basis of recovered Merlin parts.

 

[pbehn]

Wow! You are right. From wiki

Development started with the use of recovered Merlin engine parts from crashed aircraft. While unsuitable for re-use in aircraft, the Rolls-Royce chassis division had begun collecting and refurbishing them in the hope of finding a use. Robotham was approached by Henry Spurrier, of Leyland Mechanization and Aero, to ask about help with tank powerplants. Based on Spurrier's requirement, the first prototype Meteor engine (and subsequent production of Mark 1 engines) was assembled on the basis of recovered Merlin parts.

A Merlin would be very expensive to make today, even an overhaul costs a fortune but they were expensive then, if you can get viable tank engines better than the UK had at the time from what would be scrap, then it is a real winner. I saw a documentary, mainly concerned with UK jet engines but the Meteor was involved in it, they all mentioned crashed planes as Wiki does, but belly landings are just a controlled mild crash.

As per the wiki article, RR gave the Meteor version of the Merlin in return for RR taking over Rovers jet engines which became the RR Welland, obviously both had to cooperate with each other a lot for it to happen.

 

[Deleted member 68059]

In the days of wooden props (which instantly shatter) the engines were apparently relatively ok on many occasions. Once metal props came in,
it was not the case anymore, as of course they dont shatter (which also absorbs some energy), being ductile so they damage the engine a lot more.

 

[gumbyk]

That would be a great alternative - I seen a Cessna 172 have a prop strike which I thought was pretty bad. The owner did a run out inspection on the prop flange and replaced the propeller. He then flew the aircraft another 1000 hours (put 3000 hours total on the engine) before he decided to have it overhauled! This was all before the mandatory inspection from the manufacturer and airworthiness directive came into play.

I've seen that happen.
I've also seen relatively minor impacts cause excessive runout on the crankshaft. There seems to be quite an element of luck about it.

 

[gumbyk]

In the days of wooden props (which instantly shatter) the engines were apparently relatively ok on many occasions. Once metal props came in,
it was not the case anymore, as of course they dont shatter (which also absorbs some energy), being ductile so they damage the engine a lot more.

A lot of those higher-powered engines also had a gearbox between the engine and prop that took the main shock load. So, while the engine may have been serviceable, the gearbox may have been wrecked, even with the wooden prop.
Back then, it would have been more important to keep an aircraft in the air.
Now, it's going to be an insurance claim anyway, so why not let them pay for the tear-down of the engine?

 

[Admiral Beez]

Any prop strike usually results in at least an engine teardown and inspection,

This Seafire prangs its nose but just got a prop swap.

 

[FLYBOYJ]

This Seafire prangs its nose but just got a prop swap.

I've seen that before. I guess if you're under attack and the engine starts you have no choice, but that is a huge risk

 

[pbehn]

I've seen that before. I guess if you're under attack and the engine starts you have no choice, but that is a huge risk

Plus with reference to other posts especially Calum's, the tip shattered because it wasnt a metal one. In that situation I think any pilot would prefer to take off if the engine runs at all rather than sit in the ship.

 

[gumbyk]

I've seen that before. I guess if you're under attack and the engine starts you have no choice, but that is a huge risk

Yeah, there's a lot that's usually involved in a prop swap that wouldn't have been done there. Run-ups for leaks, balance checks, etc. Those aren't normal operations.

I've ferried an aircraft after a prop strike to get the engine tear-down done. There was a prop change, crankshaft run-out, and extensive ground running carried out; I was limited to not flying over built-up areas, and couldn't take passengers.

Just because it can be done in a certain situation doesn't mean that it's normal procedure.