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Flying a Taildragger

Posted: Sun Oct 01, 2017 10:04 pm
by Colonel
Was talking to a nice guy I had just met, he built
an RV-7 taildragger (how could he be anything but
nice?)

So I asked him what prop he had - and the answer
was "composite" (blade) which told me an awful lot
about his airplane would handle.

See, taildraggers either have metal blade props, or
they have non-metal (composite, wood) blade props
which weigh a shitload less than metal blades.

This profoundly affects their handling, which we
give a shit about, as pilots.

If you're a physics guy, you might remember the
governing formula, which is the integral of radius
squared, dm.

But as my father said after he saw my high school
award for highest marks, "you study too much".  I
actually didn't know there was an award.  I just
found the material simple.  Then, I got expelled,
but that's not important right now.

What you [b]need to know as a pilot[/b], is that if your
taildragger has a metal blade prop, there will be
[b]pitch-yaw coupling[/b].

If your taildragger has a prop with light blades,
there will be very little pitch-yaw coupling.

Even if you don't give a flying fuck at a donut
about aerobatics, which is really affected by
pitch-yaw coupling, if you want to fly a taildragger,
at some point you will probably want to raise
or lower the tail.

For example, if you do a wheel landing, if you
have a prop with lightweight blades, you can
arrogantly plop the tail down.  I yelled at my
son when he did that in the PT-19 Cornell with
a wooden prop.  Bad form, even if he got away
with it.

However, with a metal blade prop, if you plop
the tail down, into the right ditch you go, assuming
you are flying behind a western engine.

Same thing on takeoff.  You raise the tail, the
nose goes left, with a metal blade prop.  With
a lightweight prop, hardly noticeable.

I was told all sorts of nonsense about the Beech 18
before Chuck just told me to get in the fucking
thing and check myself out.

[img width=500 height=332][/img]

With it's metal blade props on it's R-985's, this
is the dominant ground handling characteristic
of the Beech 18.

When the tail comes up on takeoff, it wants to
yaw left so give it a bit of differential power.

When the tail comes down on landing, it wants
to yaw right so be prepared with a tap on the
left brake.  A burst of right throttle is possible
but really helping the whole deceleration thing
that's kind of the objective during landing.

That's all you really need to know, to fly a
Beech 18 or I suspect, a DC-3 or C-46.  My
father said the DC-3 was much more docile
than the Beech 18 which had a reputation of
being a little squirrelly on wheels.

One of the best pilots I have ever met, Freddy
Cabanas, told me to not fly a Beech 18 unless
the tail locked and it had a good [i]left[/i] brake.

tl;dr  [b]with a metal blade prop, raise and lower
the nose [size=12pt]slowly[/size] on a taildragger[/b]

I know.  I think too much.  Gets me into terrible
trouble.

Re: Flying a Taildragger

Posted: Mon Oct 02, 2017 1:59 am
by Slick Goodlin
Would a RV care much about the weight difference between a wood/composite and a metal prop?  I understand the gyroscopics and whatnot, just seems that neither is really heavy enough to make a difference.  Kind of like a wood vs metal prop on a Champ, I can't feel a difference.

What do you think about wood vs metal on the Pitts for takeoff and landing?

Re: Flying a Taildragger

Posted: Mon Oct 02, 2017 3:15 am
by Colonel
I found a tremendous difference in the S-2B when I
switched from metal to composite.  The gyroscopic
precession of that metal blade prop was tremendous,
and nearly disappeared with the composite blade.

A short fuselage, high RPM and a large diameter prop
all exacerbate the effect of gyroscopic precession and
vice versa.  If you want to flatten an inverted spin,
after all, power can do that nicely.  Pop quiz - in which
direction?

Occasionally I will see an aerobatic taildragger with
a 3-blade metal prop and I just shake my head.  I
met a guy at an airshow with a setup like that on
his Bucker Jungmann, I think it was.  I told him he
was going to break his crankshaft.  He smiled and
said, "I know".

And people say [i]I'm[/i] nuts?

[youtube][/youtube]

I suppose you can do it at the end of your show?

What I have learned in my life is that if you comprehend
the underlying mathematics, physics and engineering of
your activity, you can master it safely.

tl;dr

[b]Keep the metal happy[/b]