Cessna 337 crash near Gainesville

dmccormack said:
Must have been making some power -- front prop is pretty warped.
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If I'm not mistaken it's bent the wrong way. Prop strikes under power have the prop tips bent forward, no power has them bent back.
 
slowjoe said:
If I'm not mistaken it's bent the wrong way. Prop strikes under power have the prop tips bent forward, no power has them bent back.
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Really? Seems to me forward progress would bend 'em back.

Impressive structural integrity for the cabin. Looks pretty good. Don't know about the impact speed/angle, but not a bad advertisement for C337 survivability.
 
No Fuel
Water
JetA
Or, departure with known failed rear engine.....and any of the above.
 
The Gainesville article was surprisingly well written and accurate. For all we banter about media inaccuracies, they did a reasonably proficient job! Kudos!
 
flyersfan31 said:
Really? Seems to me forward progress would bend 'em back.

Impressive structural integrity for the cabin. Looks pretty good. Don't know about the impact speed/angle, but not a bad advertisement for C337 survivability.
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As explained to me: under power the propeller is moving faster than forward velocity and the pitch of the prop and force from the engine causes it to bend forward. No power then the forward motion of the plane bends them backwards.

I can believe it too. Not too long ago we had a twin land with the gear up. The pilot realized his mistake, gave it full power but it was too late. The blades on that plane were all bent forward.
 
slowjoe said:
As explained to me: under power the propeller is moving faster than forward velocity and the pitch of the prop and force from the engine causes it to bend forward. No power then the forward motion of the plane bends them backwards.
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Plausible, maybe, on asphalt or concrete but I don't think it applies when the tips of the props can dig into a grass surface like this 337 landed upon.

I would think that the tips digging into the stationary ground + plane moving forward = props bent backwards, regardless of whether the engine is making power or now.

I'm not sure I buy the theory if the prop is stiking a more solid surface either because in most cases, even if the theory is true, the engine won't be making power during the entire crash skid.
 
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bbchien said:
Or, departure with known failed rear engine.....and any of the above.
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I really, really hope that wasn't the situation.

For all its warts I've always like the Mixmaster.
 
slowjoe said:
If I'm not mistaken it's bent the wrong way. Prop strikes under power have the prop tips bent forward, no power has them bent back.
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Thats an OWT.

I attended the Aircraft Accident Investigation Course at OKC. On the class about propellers that's the first myth they debunk.
 
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TangoWhiskey said:
Interesting. Is Lombardo's book Advanced Aircraft Systems incorrect, or is it a "not always the case" myth? See the section on "thrust bending force" on this page:

http://books.google.com/books?id=Ir...&resnum=1&ved=0CBIQ6AEwAA#v=onepage&q&f=false
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The class I attended at the Transportation Safety Institute (which trains the FAA as well as NTSB Investigators) when we got to Propellers, the first thing the instructor did was dispel the myth of propellers always bend forward under power. We covered several case studies of both powered and unpowered and how to tell the difference.
 
Rotor&Wing said:
The class I attended at the Transportation Safety Institute (which trains the FAA as well as NTSB Investigators) when we got to Propellers, the first thing the instructor did was dispel the myth of propellers always bend forward under power. We covered several case studies of both powered and unpowered and how to tell the difference.
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You're not giving a complete answer. Did they say that propellers under power do not always bend forward, only sometimes, never bend forward without power, etc? I could see the possibility that under power does not always cause the tips to bend forward, but a windmilling or moderately powered propeller would never cause the tips to bend forward.

Think of it this way: you're moving forward at say 100MPH, but at full power your propeller tips are spinning at say 580MPH (76" @ 2,500RPM). The forward speed against the tips is really insignificant compared to the spinning force on the tips. The pitch of the tips is going to bend them forward, assuming that the contact rate is low, as would be in the case of a normal landing without the gear being down.
 
To finish my comment above, the one thing to remember about aircraft accidents are that no 2 are the same. Several factors that play into prop bending include angle of impact, pre impact (tree limbs, etc) and power being produced or windmilling. Props are ductile and the bending tells alot along with scarring of both the ground and the blades.

I don't have my handbooks handy here from the class but they have lots of good information.
 
slowjoe said:
You're not giving a complete answer. Did they say that propellers under power do not always bend forward, only sometimes, never bend forward without power, etc? I could see the possibility that under power does not always cause the tips to bend forward, but a windmilling or moderately powered propeller would never cause the tips to bend forward.

Think of it this way: you're moving forward at say 100MPH, but at full power your propeller tips are spinning at say 580MPH (76" @ 2,500RPM). The forward speed against the tips is really insignificant compared to the spinning force on the tips. The pitch of the tips is going to bend them forward, assuming that the contact rate is low, as would be in the case of a normal landing without the gear being down.
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I think the answer you're looking for here is that the blades typically bend forward if the prop was producing substantial thrust and backward if not when contact between prop and something more solid than air occurs but as R&W has stated this is not absolute, there are other factors. I can say that AFaIK a prop biting into asphalt, sod, or even water will likely bend forward under full power during a gear up landing or a ditching. And like R&W also stated, I expect that there are other reliable markers to determine if the power was on.
 
Dave Siciliano said:
Here's what happened another time in a 337.


http://www.ntsb.gov/ntsb/brief.asp?ev_id=20020621X00957&key=1

Best,

Dave
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The Gainesville plane was a "G" model that has intergral tanks in each wing, the left wing supplies the front engine and the right wing supplies the rear. There are no "aux" tanks to switch to unless they have been added by STC.

The earlier Skymasters (65-72, A thru F) such as the one mentioned in the NTSB report did have L and R Aux tanks with return lines to the main tanks. Fuel management in the earlier models took some thought and system knowledge.
 
It ripped a wing off and no fire? Interesting...
 
the propeller sitting in my living room has one blade bent forward and the other backwards. it was at idle when the gear collapsed
 
Tony: would you consider doing an interior decoration job for a third party? You're cave sounds really cool!
Do you have shades on lamps or just bare bulbs? Any other tips <g>

Best,

Dave
 
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