FW: REFLECTOR: Falling objects through the prop and what happensifthe
door doesn't come off
Brian Michalk
michalk at awpi.com
Mon Mar 14 19:16:35 CST 2005
Brian Michalk <http://www.michalk.com>
Life is what you make of it ... never wish you had done something.
Aviator, experimental aircraft builder, motorcyclist, SCUBA diver
musician, home-brewer, entrepreneur and barely single
-----Original Message-----
From: Rodney Brim [mailto:rb at managepro.com]
Sent: Saturday, March 12, 2005 9:24 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: RE: REFLECTOR: Falling objects through the prop and what
happensifthe door doesn't come off
I had a near fatal encounter with the door opening and not coming off. I
sent in some suggestions to the factory, which should be part of all your
emergency procedures. I have since rehinged my doors from the front, and
the open quite nicely in flight without creating any problems - although I
can't close them once they are open until I'm back on the ground ;)
Bottom Line: If the door pops all the way open and doesn't tear off,
(which mine didn't, in my case it was the co-pilot door and it swung all the
way up and I couldn't reach it) you will be in an emergency.
1. The aircraft will be moderately directionally unstable - you now have a
dorsal fin of sorts in the middle of the aircraft and the plane wants to
wander around that center - its still quite flyable.
2. The curved door is a spin waiting to happen. As soon as you turn away
from the door, the plane will begin an involuntary roll away from the door,
and drag will increase quickly. You will be in what would be a stall-spin
configuration in a conventional plane. Speed will be dropping like a rock,
as will the plane, and you're best efforts to stop the spin and return to
straight and level will result in a bank exceeding 60 degrees. In my case I
was departing the airport at 200 feet agl. At this altitude, once you
initiate a roll, you will have less than 5 seconds to get it right or meet
your Maker.
3. Don't turn away from an open door in a Velocity. Turn into it, you'll
pin it against the fuselage and stabilize it against the air frame. You'll
have tremendous drag, but its flyable. I have 325 hp and I could maintain
altitude at full power.
4. With all the drag, the plane is going to feel like the gear is hanging
out. In all the noise and confusion, charts flying around, you won't be
able to hear through your headset - remember that the gear isn't down (I
didn't) but don't drop it until you've made the field, because it obviously
will create even more drag.
Hope that helps,
Rodney Brim,
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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of bdtopp at comcast.net
Sent: Friday, March 11, 2005 5:20 AM
To: Velocity Aircraft Owners and Builders list
Subject: RE: REFLECTOR: Falling objects through the prop
Has anybody ever opened a door of a velocity (intentionally or
unintentionally) in flight? I am guessing it would depart the airplane
because of the curvature of the door.
Bruce
-------------- Original message --------------
Keith,
I'm guessing if you'd come to the point of deciding to jump out of the
Velocity, waste time getting out of there is the least of your problems.
Chuck
Do Not Archive
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of KeithHallsten
Sent: Friday, March 11, 2005 12:37 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Falling objects through the prop
Al,
When it comes to parachuting out of an elite-door Velocity, I would want
to make sure I got a good push off of the door sill on the way out! Also,
since opening the door will likely start a roll, you wouldn't want to waste
any time in making your departure.
Keith
----- Original Message -----
From: Al Gietzen
To: 'Velocity Aircraft Owners and Builders list'
Sent: Thursday, March 10, 2005 9:02 PM
Subject: RE: REFLECTOR: Re: Falling objects through the prop (Was NOSE
WHEELGOTSIDEWAYS)
Keith;
Yes, I realized as I went back out to the shop that my
thinking-out-loud analysis was all wrong; so Im glad you followed up. At
first your 1.4 inches seemed too small, but the math is correct. I think
the fact that the object is initially at the speed of the plane makes a huge
difference, and makes it likely a small metal object (small and dense) would
clear the prop, probably by some margin. It only needs a < of a second to
make it.
Some time ago I remember doing some back-of-the-napkin analysis with a
couple of Long EZ drivers which concluded that a person could safely
parachute out of an elite door Velocity, but it may have been a somewhat
used cocktail napkin.
Al
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
To: 'Velocity Aircraft Owners and Builders list'
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, lets see; at 120 mph thats 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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