Chris,
You have gotten many good pieces of advice on your oscillating A/S and Alti
meter.
There are three things that Jeff MacDonald of Mac Avionics told me long ago
and has born out in my research on line as well as my own hard learned les
sons.
General:
The Europa XS underwing pitot and static tube is excellent and is within a
couple knots and 50 feet when installed as directed.
Cockpit static as a source is also quite close to the wing mounted static.
Installation errors are normally the instrument calibration itself. It has
been my observation that the airspeed indicators I've installed all read w
ithin their tolerance during in flight and ground certification checks usin
g the XS underwing pitot/static. Instruments errors must be tested for. I
don't use manometers in my garage and the standard atmospheric tables, I h
ire an avionics guy to check my instruments if I don=92t see the 1000 foot
check.
Specific to the Europa:
The wing to fuselage connection is a pair of Colder Products Company (CPC)
PMC 2202 and 1702 quick disconnects. These 1/8 barbed and 1/8 inch flow co
nnectors are excellent but the O ring on the PMC2202 can be cut very easily
. Also, the O ring will deteriorate with age. Look over the O ring carefu
lly, if it is rough feeling or you can see a crack in the surface, change t
he O ring. Part number from CPC is 730800. Get 10 if you used a number of
them in the panel also as I have. They last about 5 years. It is common
after a build to see a leak in these due to O ring age when left out of the
package.
A new aircraft with no wing to fuselage gap seals will have prop blast and
wind induced oscillations at the root. On a two blade you can almost count
the pulses. Any leak in your fitting at the root will cause errors in the
instruments using either pitot or static.
I am not afraid of using cockpit static during tests. This limits the stat
ic problems to the cockpit and panel. It makes sorting out issues in fligh
t easier in my opinion.
Specific to instrumentation:
Altimeters that fluctuate have an aneroid that is failing normally. Jeff c
aught it on my pitot static certification check. My Kollsman altimeter wou
ld catch and hang up is what I thought and Jeff found that the aneroid was
the most likely cause. It was, and the rebuild of this used certified alti
meter was ugly. A bad altimeter or airspeed indicator internal leak will c
ause errors.
EFIS and Autopilots can cause fluctuations that are cyclical. I found this
out with a TruTrack some years ago. Typically, it is the diaphragm on the
board mounted pressure indicator. It vibrates as it begins to fail causin
g fluctuation. Then it dies. I have never had an EFIS fail, but Jeff MacD
onald has had it happen in Garmins and Dynons.
Servo altimeters are not used in light aircraft but they are a very common
cause in fluctuations.
Airspeed indicators are a combo of pitot and static of course. I had a win
ter A/S indicator fail internally. Bouncy Altimeter and fairly steady airs
peed was noted. Winter fixed it for free plus shipping. But then again, I
really like my wind around airspeed indicator and the repair was great unti
l the needle fell off and I had to send it back again. I have paid more in
shipping than for my airspeed indicator. But I like what I like.
Testing or How to tell quickly (well sort of quickly):
We talked about the 1000 foot check on the ground by pulling by mouth one i
nch of mercury then capping off the tube. Altimeter climbs and holds 1000
feet, and the airspeed reads 135 Knots.
Vertical speed indicators climb during this and a good VSI normally goes ba
ck to zero with only about 50 foot loss and then stabilizes out at a very s
low bleed. Cheap VSIs will bleed nearly 300 feet per minute. Leaky A/S in
dicators begin to fall off speed and so one may have to test each instrumen
t separately.
I will normally begin inspection by pulling off the pitot/static tube from
the wing first and inspect.
Is the W33 plastic tip intact and secure.
Are the two 1/8 OD nipples inserted into the tube going into the wing secur
e.
If so, remove the pitot/static tubes from the wing pull the static and pito
t lines off (mark them) and using the same 1/8 ID polyurethane tubing that
comes in the kit, attach about 10 feet of the 1/8 inch hose used in the ki
t to the static line with a barb to barb fitting and go to the cockpit and
pull a small vacuum to raise the altimeter to 1000 feet. If it leaks. The
n pull the wing first and check the wing connection or any other connection
in the wing to the pitot/static tube. Yes, you will have to pull both the
wings on a mono. Always fun.
If the coupling or something in the wing connection leaks, fix it.
If the wing to pitot/Static is good, it is in the fuselage/panel. Hopefull
y, your panel rear access is convenient.
If the panel is suspect:
When using 1/4 inch Nylaflow and compression fittings rather than the 1/8 p
olyurethane hose and barbs, you have to check the compression fittings. Th
ese fittings and the 1/8 NPT screw in fittings are prone to leaks if not in
stalled properly. NPT threads must have the proper tape/sealant prescribed
by the manufacturer. The compression fittings must be snug but not over t
orqued to failure. Do not deviate from the manufacturer's fittings and ti
ghtening techniques/procedure.
I must confess on my Winter A/S indicator which has 4mm barbs, I heated the
tube to stretch it over the barb and some cheap plastic Tees when upgradin
g my panel to the Winter. Three years later, I found a static and pitot le
ak at the A/S indicator as the heated polyurethane took a set and without a
clamp simply sagged and started leaking. Use the proper tube for the barb
or pay the price. Good solid brass tees are better for longevity than pla
stic barbed tees in a panel.
No more stories of my screw ups.
Pull a vacuum again on the static connection in the panel/fuselage. Then a
bit of pressure on the pitot. If all seems stable. You must isolate inst
ruments.
I start by pulling the static line loose in the panel. If you have roaring
inlet air coming into your panel this will disturb the static. You will n
eed to plumb the static to the cockpit (near your feet normally is fine or
face of the panel). I personally disconnect any instrument that uses pitot
and static. So, the altimeter and altitude encoder (if you have a separat
e one) are one static source. The airspeed is static open alone as are the
EFIS and Autopilot.
Go Fly. Observe and land.
If the altimeter, transponder altitude (if you have a window for that), and
VSI seem to steady out. Look to the A/S indicator and EFIS and see how t
hey perform. He which is in error is the bad component. Autopilots are sn
eaky as they show and tell nothing usually.
I don't worry about massive errors in using cockpit static nor do I worry a
bout compromising my flight safety in a light airplane at low altitude. Th
ere are no pressurization worries only fittings and leaky fittings/instrume
nts.
With complete pitot/static failure, we are now in the age of redundant redu
ndancy.
Everyone seems to have an aviation AP on their phone with maps, ground spee
d distance to here and there and they are neat. We also have in panel GPS
information. So, loosing the pitot/static is a no brainer any longer, but,
you must note that GPS gives ground speed only.
For me (and you will develop your own feel) I use:
Look at the wind sock, listen to ATIS or watch the ripples on the lakes and
leaves in the trees and estimate the wind. Calculate your final ground sp
eed.
Throw out the gear/flaps at 80 ground speed and fly the turn at 75 or so, t
hen settle on your calculated final ground speed.
(Flaps and gear have been ops checked well over 90 KIAS by a number of pros
pective buyers.)
Proper contact flying tells us to memorize pitch and power settings. I use
4000 RPM/22 inches power, the horizon is 3-4 fingers from the panel top, a
nd that is about 80 knots on downwind. Trim the plane for that.
Drop the flaps and 5 clicks of down trim and fly around the corner at 75 in
a smooth turn. If the stick is heavy you are too slow, if you must push y
ou are too fast. Fly with your fingers and Europa acts like Goldilocks "ju
st right on the stick pressure ".
Roll out slowing to computed speed plus a little and add back 5 clicks of u
p trim and look at the aimpoint and use the VASI/PAPI lights and/or note yo
ur aim point comfortably above the nose a finger or two and I'm on speed (i
sh). The rest is sight picture.
Trigears are easy to get the approach on speed, Monos are a bit trickier bu
t similar techniques can be observed. Long runways and slow flight practic
e down the runway will put me down safely without incident. Practice, prac
tice, practice.
Good night.
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of n7188u
Sent: Saturday, April 03, 2021 6:58 PM
Subject: Europa-List: Re: N11EU (kit A291) Flies
rb@gmail.com>>
Martin,
I have the wing mounted pitot/static.
Chris
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