REFLECTOR: Re: Falling objects through the prop (Was NOSE WHEEL GOTSIDEWAYS)

[Tom Martino]

Except ... it didn't.

 

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of KeithHallsten
Sent: Thursday, March 10, 2005 6:48 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Re: Falling objects through the prop (Was NOSE WHEEL
GOTSIDEWAYS)

 

Al,

 

I follow you up through the point where you say the object will only
fall 85 msec before the prop comes by.  However, as I recall the
position formula is:

   X = X(init) + V(init)*T + 1/2 A*T*T.   If we use the initial
elevation of the object as our datum, X(init) = 0, and if the initial
downward velocity, V(init), is also zero.  If we further assume that the
only acceleration acting on the object is gravity (32.2 ft/sec^2), then

 

  Distance Fallen = 1/2 * (32.2 ft/sec^2) * (0.085 sec) * (0.085 sec) =
0.117 ft  = 1.40 inch.

 

So does your prop arc extend lower than 1.4 inches below the level of
your nose gear door?  Sure!  

 

However, we have neglected the fact that any object that falls off the
plane is initially at the speed of the plane, not at rest, and it is
slowed by air friction, so it is decelerating horizontally while is is
accelerating vertically downward.  If we know the drag coefficient of
the object that's falling, we could calculate that deceleration due to
the relative wind, but that will be left as an exercise for the reader!
Suffice it to say that the object will actually fall significantly
longer that 85 msec, and will therefore fall farther.  If the prop arc
extends, say, 16 inches below the belly of the plane, we would need to
have approximately 1.0 second of fall to clear the prop arc.  Is this
likely?  Probably not.

 

I think the conclusion is that anything that falls off the fuselage,
even from the nose, is pretty likely to pass through the prop arc.

 

Keith

      

	----- Original Message ----- 

	From: Al Gietzen <mailto:ALVentures at cox.net>  

	To: 'Velocity Aircraft Owners and Builders list'
<mailto:reflector at tvbf.org>  

	Sent: Thursday, March 10, 2005 8:08 AM

	Subject: RE: REFLECTOR: RE: NOSE WHEEL GOT SIDEWAYS

	 

	Subject: REFLECTOR: RE: NOSE WHEEL GOT SIDEWAYS

	 

	Tom

	 

	You say believed you lost the "T" fitting in flight.  Did you
check the Velocity high speed rotating strainer that's attached to the
engine to see if it was detected, evidenced by leaving 'memory marks'?
Idle curiousity:  Can anything fall off the plane's fuselage without
going through the prop at rotation speeds or above?

	 

	Chuck

	 

	Well, let's see; at 120 mph that's 176 ft/sec - so it takes
about 85 msec to travel 15 ft.  If you drop something from the nose gear
well, it will travel downward a max of about 30 - 35 in. before the prop
goes by.  It might clear the prop.

	Just thinking out loud, check my math.

	Al

	
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