[NSRCA-discussion] 747 Snap Entry?

[chris moon]

I had a DC-10 flight engineer instructor who used to say you can try 
anything you want....once.  If you are still alive after that, maybe you 
can try it again.  That was his way of strongly suggesting that you 
might want to follow the flight manuals and not get creative on your own 
inside a 400,000lb airplane.  I will never forget his message.

Chris

John Konneker wrote:
> American Airlines....more like 30 years ago.
> Help me out here Chris.
> There was a supposed "step" the 727 could be flown on that would 
> increase performance.
> Whoever was in the cockpit...first officer or captain...pulled the 
> circuit breaker so that he could do whatever he
> did with the flaps or slats.  When the other returned to cockpit he 
> saw the breaker out and pushed it in.
> That's when whatever happened happened...plane went way beyond 
> Vne...blew the leading edge devices off.  Terrorized
> the passengers in the cabin...did a big split S or similar before 
> control was regained.
> The story goes on  that the cockpit crew erased the cockpit recorder 
> so nobody really ever knew what happened.
> That's the version I heard anyway as told to me by Tom Street at the 
> Mesquite, Texas contest way back in like '83.
> JLK
>
>> To: nsrca-discussion at lists.nsrca.org
>> Date: Tue, 1 Jul 2008 17:47:18 -0400
>> From: rcmaster199 at aol.com
>> Subject: Re: [NSRCA-discussion] 747 Snap Entry?
>>
>> A few of us were discussing just such an occurence recently which
>> apparently happened by accident and darned near crashed the plane. Dean
>> remembered the details which went something like this:
>>
>> The pilot of the 727 about 20 years ago had the plane trimmed as far
>> aft as possible and had inputed a bit of flap to use fuel most
>> efficiently. The co-pilot, soon after returning from a visit to the
>> loo, saw the trimmed flap and flipped the switch to return the flap to
>> neutral. This action immediately made the plane too tail heavy which
>> made the plane do a pretty violent half snap to inverted. The pilot
>> lost close to 25k feet pulling the plane out of the dive, which he did
>> successfully but not before deploying the gear to slow the crate down.
>> That had to be some kind of experience
>>
>> Legend has it that the pilot then went straight to loo himself to
>> change his britches (G)
>>
>> Matt
>>
>> -----Original Message-----
>> From: Koenig, Tom 
>> To: General pattern discussion 
>> Sent: Mon, 30 Jun 2008 10:25 pm
>> Subject: Re: [NSRCA-discussion] 747 Snap Entry?
>>
>> Hey John,
>>
>> Out of interest.....has anyone ever attempted a snap in an airliner???
>>
>> I have heard of a captain doing a slow roll in a 747....but a snap? Is
>> it possible?? What does a simulator do when pushed to such limits ( I
>> know a simulator cant snap BTW...well, I assume any way LOL!!)
>>
>> Tom
>>
>> -----Original Message-----
>> From: nsrca-discussion-bounces at lists.nsrca.org
>> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of John
>> Gayer
>> Sent: Tuesday, 1 July 2008 11:42 AM
>> To: General pattern discussion
>> Subject: Re: [NSRCA-discussion] Snap Entry
>>
>> Actually a snap can occur without any aileron input...but I challenge
>> anyone to show a pattern ship doing a snap roll on a 45 degree downline
>> without ailerons.
>>
>> The approach snap can occur with only the use of elevator and it
>> involves one wing panel stalling before the other. Try an approach with
>> crossed controls(aileron/rudder with some power. pull the nose up
>> gradually and see which wing drops. It will be the wing with the aileron
>> trailing edge down. This is contrary to what we see in a pattern snap
>> roll which always snaps in the direction of the aileron deflection thus
>> indicating the lack of any stalled condition
>>
>> John
>>
>> seefo at san.rr.com wrote:
>>
>>>Just to stir the pot a little further..
>>>
>>>I'm not sure a contemporary pattern plane can generate enough pitch
>> rate to reach critical angle of attack and properly perform a snap roll.
>> I think it's far more likely that we're seeing nothing but a heavily
>> yawed aileron roll, with the pitch break only being shown to judges to
>> convince them there is actually a stall happening, when in fact there is
>> not.
>>>
>>>If a snap cannot occur using ONLY elevator and rudder, then the wing is
>> not stalling. Aileron inputs into a snap actually inhibit flow
>> separation, as the inboard wing angle of attack is drastically reduced,
>> and the outboard wing AoA is drastically increased.
>>>
>>>But since there is no way to actually determine what is happening
>> aerodynamically on an F3A airplane, the best a pilot can do is fly the
>> airplane to what the judges expect to see based upon the rules. It
>> really doesn't matter what the control inputs are if the airplane LOOKS
>> like it's doing the right maneuver.
>>>_______________________________________________
>>>NSRCA-discussion mailing list
>>>NSRCA-discussion at lists.nsrca.org
>>>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>>
>>>
>>>
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