Newsletter May 2018.
Next meeting Thursday, May 10.
7:30pm, Blair Field Clubhouse.
Vernon Rust Remover
It was held on Saturday May 5.
Dave Jones had called me a few days before and offered me a ride there in his
aircraft. That was an offer I could not refuse! As it
turned out, I took off from Dave's strip shortly before 8am, with Dennis in his
Tri Pacer. And I came back with Dave in his PA-14 after the Rust Remover; that
sure was different than flying my little Beaver! I think that those guys
are trying to give me the bug to get back into flying!...
There seemed to be a couple hundred people
attending, and the speakers were very interesting.
The weather was great; a bit of heat turbulence, but
nothing the PA-14 could not handle. It was a bit harder on the relief pilot!...
Some aircraft seem to have not moved for ages, like this
The Secret to Good Landings:
Angle of Attack and Airspeed
By Dan Thomas
Earlier this year we had a look at Angle of
Attack, how it changes in various maneuvers, its limits, and how to fly safely
by avoiding those limits. This month we'll see how it affects the quality of
landings and why so many pilots just can't seem to get decent touchdowns and
Now, boys and girls, a bit of review: A wing,
to support the airplane and its load, needs both airspeed and angle of attack (AoA).
If the airspeed is lower, the AoA must be higher, and if the airspeed is high,
the AoA will be lower. That's why the airplane's pitch attitude is high when
you're in level slow flight, and the attitude is lower in level cruising flight.
And it's why too much speed on arrival at the runway makes the airplane's pitch
attitude all wrong for touching down safely and neatly.
The airplane will have a book that will give
appropriate speeds for a bunch of maneuvers. Many years ago those books were
called Owner's Manuals. Then someone figured they should be called Pilot
Operating Handbooks (POH). That became unfashionable and now a new airplane
comes with an Aircraft Flight Manual (AFM). In the 1950s an Owner's Manual might
have been a few pages thick, and that persisted in some factories up until the
mid-1970s; we had a '76 Bellanca 7GCBC Citabria that had a four-page manual.
These days an AFM is hundreds of pages, mostly due to liability concerns; the
owner has to be warned of every possible way he might kill himself, and it takes
many pages to do that. The unintended consequence of such verbosity is that few
pilots read these things and some don't seem to believe them. When it comes to
approach speeds, pilots get comfortable with adding a few knots "for safety,"
then a few more, and if they're high on approach they just dive at the runway,
which adds even more speed. All that velocity makes good landings completely
impossible and increases the risk of an accident enormously.
First, the effect on AoA. As we saw a minute
ago, too much speed reduces it. If we arrive at the runway's surface with
excessive speed, the airplane's pitch attitude is low, and there are a number of
things that can happen here. The nosewheel can contact the runway first, and
with the main wheels still off the surface, the airplane's downward movement
results in the nose being forced upward, which increases AoA, which makes the
airplane lift off again. We call that a "bounce," but it's really an increased
AoA that put the airplane back in the air. The pilot's first reaction is to push
the nose down; the nosewheel hits again, and up we fly once more. This is called
"porpoising," and it breaks a lot of airplanes. Nosewheel structures, firewalls
and internal supports all get bent, buckled, broken and torn. Owners' wallets
get emptied. Insurance companies and Transport Canada start wondering about
Here's what it looks like:
For some more convincing, see this:
A second thing that can arise from too much
speed is "wheelbarrowing." If the nosewheel touches down gently enough, it might
roll along, and the mains are still in the air. Essentially, we now have a
really nasty taildragger. If the pilot is holding the nose on with the elevator,
that nosewheel has plenty of traction, and if the airplane swerves even a
little, the centre of gravity will make the airplane groundloop. More expensive
noises. At about the 46-second mark in this video, it starts to get away on the
pilot, but he raises the nose just in time:
Wind Landing followed by Wheelbarrow
Landing a tricycle-geared airplane flat so
that all three wheels touch down at the same time is also a really good way to
wear out nosegear steering parts. Very few nosewheels are dynamically balanced
like all automobile wheels get when they get new tires, and so they tend to
shimmy, which wears out torque links and shimmy dampers and tires. Landing at
sane speeds saves that nosegear, since it won't touch down until the speed is
quite low. (Nasty shimmy is often cured with a dynamic balance, but machines
that can handle aircraft wheels are rare and expensive. I had to build my own.)
For an example of shimmy, see this. And also note the flat, fast approach that
resulted in a long float of a thousand feet or more:
M Nose wheel shimmy
That nose gear needs some serious fixing. It
doesn't have to do that.
"Ballooning" is a third phenomenon related to
excessive speed. The airplane nears the surface, the pilot flares just a hair
too much, and the airplane flies upward. It has turned speed into altitude, and
if it runs out of speed up there, it is going to come down hard. It might even
Too much speed also has a detrimental effect
on stopping distances. The formula for kinetic energy is K=1/2MV^2. Kinetic
energy (K) is what we have to dissipate in order to stop, and since we can't
easily change the mass (M) of the machine , we have to control the velocity (V).
Doubling the velocity quadruples the energy to be dissipated, because of the
squaring effect of the formula. Even a 10% increase in speed results in a 21%
increase in energy, and a 20% increase in speed gives 44% more energy. That
energy has to go somewhere, and we sometimes read of the places it went: All the
way down an embarrassingly long runway, maybe right off the end; blown tires,
burned brakes, into the trees, and so on. More skill-testing questions from
And that speed also creates more lift,
remember. A landing is not over just because the wheels are on the ground. There
is still airflow over that wing, and it is still lifting. Maybe not quite enough
to pick up the airplane, but it sure is reducing the weight on the wheels, and
those wheels have very little grip on the surface. Too many pilots try to fix
fast landings with the brakes, and aircraft shops make money replacing roasted
brakes and flat-spotted tires. None of those things are cheap. Even worse than
the cost is the knowledge that personal airmanship could be a lot better.
Back to the POH or AFM. It gives approach
speeds based on gross weight. Those speeds are typically around 1.3Vso, or 1.3
times the airplane's stall speed in the landing configuration. If you're under
gross, the speed could be reduced a small bit. Now, if we have a 172 that
stalls, at gross, at 48 MPH with the flaps down and power off, the approach
speed will be around 62 MPH. The POH might say 65. Whatever. Do you fly that
airplane at 65, or do you approach at 75 "just to be safe?" Or 80? At 75 we've
added at least 33% more energy, and at 80 we have over 50% more. This is at full
flaps, remember; less flap will give different speeds, and different airplanes
will have different speeds. Read the OM/POH/AFM. If you still think that the
published speeds are too slow, go do some power-off stalls at altitude with an
instructor and see what the airspeed indicator says when the airplane stalls.
And how much before the actual stall break that the stall warning howls. It
might surprise you. Know your airplane.
There are other factors to consider. The air
is disturbed as much as a wingspan away from the airplane in all directions as
it moves through the air. When the airplane gets into ground effect
(approximately one-half of wingspan above the surface, or within about 18 feet
in a 172), drag drops off noticeably. In a low-wing airplane it's even more
apparent. The surface is interfering with the formation of the wingtip vortices,
which cause drag and destroy some of the lift near the wingtips, and it also
reduces the upflow of the airstream immediately ahead of the leading edge,
reducing AoA and therefore drag. Both factors tend to reduce the stall speed a
little, and add to the runway length we will consume in landing.
There's a really handy book you should read.
If you've learned to fly in the last 30 years or so, you should have seen it.
It's the Aeroplane Flight Training Manual, published by Transport Canada, and it
has this picture in it:
And there, in that picture, is what seems to
be a closely guarded secret: Bleed off the speed before you get into ground
effect. Too many pilots approach at 1.3Vso or more, and don't start flaring
until they get to within four or five feet of the surface. That's way too low.
It leaves the airplane with a lot of speed in a low-drag regime, and the usual
result is a too-fast and flat or too-long landing. Look again: At 15 to 30 feet
you're pulling back, power off. 30 feet is nearly a wingspan. This initial
raising of the nose is called the round-out, and the continued pitch-up just
above the surface is the flare. Too many landings leave out the round-out
altogether, only flaring near the surface, and it results in the problems we've
been talking about.
The airplane should touch down at minimum
controllable airspeed. That will be a speed just a little above stall, and
considerably below 1.3Vso. There's a misconception out there that this is a
"full-stall landing." It's not. The airplane is not stalled. We don't want it to
stall. We'd lose control in a stall. The nose would drop in a stall, and a wing
could drop if there was any yaw or crosswind. If it was stalled, we could lose
aileron control in a crosswind landing. If it really was stalled, a sudden gust
of wind couldn't pick the airplane up again so easily, and many of us have been
there, right? The aircraft's designer set things up so that the wing is not at
stall AoA even if the tail touches the runway. Even in a real airplane (a
taildragger, of course:-)) the wing isn't stalled. I once measured the chordline
of a Citabria’s wing as being at 12° to the surface; the stall AoA is around
17°, so we're well short of the stall when we're travelling parallel to the
surface in three-point landing attitude. I have flown along in my taildragger
with the tailwheel trundling along the runway and the mains in the air, and have
seen others do it, too. A stalled three-point attitude would not allow that.
(Flying along like that is not recommended, mind you, because you could get the
nose high enough to actually stall and break something, but it proves the error
of the "full-stall" myth.) And a chirping stall horn doesn't mean we're
stalling; they're supposed to be set to sound at five to ten knots or MPH above
the actual stall break. That's a pretty good margin.
"But, but, but..." you say. "If I flare and
level off a couple of feet above the runway and hold it there, it will
eventually suddenly drop and land hard. Isn't that stalling?" Nope. It's
sinking. You held a constant attitude and the speed decayed. Constant AoA with
decreasing airspeed means lift is diminishing. The airplane sinks, and that
descending flight path increases the AoA a bit more, adding more drag and
increasing the sink. You can get a pretty hard touchdown doing that, but if it
actually stalled the nose would have fallen; you couldn't hold it up. Airplanes
are sometimes damaged landing like that: not stalled, but a hard landing
nonetheless. Airplanes with short, low-aspect-ratio wings are more susceptible
to sinking like that. Think Cherokee or Ercoupe or short-wing Piper. Or my Jodel;
there's a stinker of a sinker for you.
Landing at minimum controllable airspeed after
a proper approach gives us a whole lot of stuff: Satisfaction that such
accomplishment brings. Minimum runway used up. Long tire and brake life. No
tangling with the ditch at the end of the runway or the rhubarb along the sides.
No busted nosegears and firewalls. No embarrassments. The options of shorter
small-town or backcountry strips for camping/fishing/whatever become open to
us. It's worth learning to land well.
From Jan Nademlejnsky
I am starting a new aviation era in my life
sunset. I bought 20 hour, 2016, Apollo DeltaJet2 with Rotax 912 (80 hp). I saw
Apollo trikes last year when I visited trike fly-in in Idaho, USA. The DeltaJet2
looks very sexy and attractive. Since that time, I searched the internet for
Apollo trike, but the price of this type of toys is outrageous.
I was lucky to spot ad in Barnstormers. The
trike was located in Lyncrest Airport near Winnipeg. The price was still, but
much less outrageous, but what the heck.
I was waiting until snow melted. Month before
my AC flight to Winnipeg, I booked 26' U-haul, which is actually 35' long
monster. Then the stress started; how to load/unload it, how to tie it down and
how to secure it so nobody gets in over night. Track like that in a motel
parking lot could be very good attraction for thieves. U-haul guaranteed that
the track would be available when I arrive to Winnipeg and if not they would pay
me $65. This is not very good guarantee. I was told to call one week before the
pick up day. I did, they did not have answer, but told me to call 3 days before
and that they will send me confirmation email, then day before... Nothing,
nothing. The last day I sent the trike seller to the U-haul location and he
verified that the truck is actually waiting for me. I was already in U-haul
office in Winnipeg when I received their email.
The truck with only 10,000 km was very dirty
inside out. I had no time to argue there, I just signed papers and drove to
Lyncrest airport. We loaded the trike with help of another three people and tied
it so it could not move during my 2,000 km journey home.
That heavy duty truck was very stiff and every
crack in road was major jolt into my body and mainly into my cargo. I have never
seen worse roads than in Winnipeg. I felt like driving somewhere in Africa. I
definitely worried about my precious cargo. I stopped east of Winnipeg to check
my load. I was not very happy. The trike front wheel instead being on the floor
was on the front wall with trike at about 45 deg with one prop blade on the
floor. It was very unpleasant, especially with no tools, help and in middle of
nowhere. Eventually I had to retie everything again to prevent more damage.
I made it to Brandon Motel and park the track
with the cargo doors right to the wall, so nobody could get in. I still did not
sleep much with all kind of scenarios running through my head. The rest of the
trip was uneventful, with another overnight with Calgary relatives.
Right now, the trike would be ready to fly if
I did not damage the prop. I am waiting for new one from USA. I have covers
still off, because I am doing some modification. I am installing battery
charging connector, 12V outlet plug and eventually transponder. I wanted to use
my transponder from the AirBorne trike, but it is too long for my available
space. I will be ordering different model from UK.
Therefore, my transponder ready to install and
use MICRO AIR T2000 will be for sale. It worked perfectly and accurately, but I
cannot use it. Here is copy of Aircraft Spruce. To get their transponder to
Canada would be more then C$3800. I will be accepting offers.
I received deposit for my AirBorne trike and I
promised that I will not fly it. So my last flight was in Apr 4, 2018