Today I arrived at the hangar with the intent
of testing the pitot and static air systems per the PAP. I purchased some modeling clay on my way out
so I would be ready for the test. The first
thing I did was attach a section of ¼" plastic tube to the pitot
tube. I then inserted a length of
1/8" plastic tube into the ¼" section of tubing. I used my heat gun to soften the ¼"
tubing so I could slide it over the pitot tube.
I then attached a syringe to the 1/8"
tubing. I depressed the plunger in the
syringe until the airspeed indicated 10 knots on the Skyview. I had to use a piece of tape to hold the
plunger in the syringe. Otherwise it
would push out and the airspeed would drop.
I photographed the screen with the airspeed at 124 knots.
The maximum leakage allowed was a drop of 10
knots in 1-minute (60 seconds). The range
timed was from 120 knots down to 80 knots.
The average time for each 10 knot drop was 126 seconds.
I then attached the 1/8" plastic tube to
one of the static ports with modeling clay as instructed. I also put tape over the other static
port. I attached the syringe and
extracted air until the altitude shown on the SkyView was 1,200' above the
current altitude. I set the barometric pressure
on the SkyView and began the test. The
allowable leak rate for the static system is 100' in 1-minute (60 seconds). I pulled the plunger on the syringe until the
altitude read 5,800 on the SkyView. I
started the stop watch. Unfortunately the leak rate on my static
system was 100' in 20 seconds. Way to
much leakage. I tightened all of the fittings,
redid the modeling clay and resecured the 1/8" tubing to the syringe. I restarted the test with the very same
results. I decided I would have to get
into the tailcone to make sure my tubing connections were good.
I went to Lowe's and purchased a 4' piece of
1x10 pine. I removed the seats and seat
backs, upholstery and carpet and baggage compartment bulkhead cover. The cover was just sitting in place so it was
easy to remove. I laid the 1x10 across the
baggage floor and through the bulkhead.
I also put a folded moving pad over the 1x10 to make the access to the
tailcone a little more comfortable. It was a really tight squeeze through the
bulkhead with the fuel tank in place but I made it. Of course getting into and out of the baggage
area was an exercise in contortionism. When I inspected the tubing connections I
found the static line connection to the ADAHRS not completely tight. I tightened it up and tried the test
again. Same results. 100' loss in altitude in 20 seconds. Back into the tailcone. I pulled the static lines from the rivets
through the side skins. They came right
off. I had installed them with clear
silicone. I cleaned off all of the
silicone on the tubing and the inside of the aluminum skins.
I got some gray RVT from my tool box and
reinstalled the lines, sealing them to the rivets and the sidewalls with
RVT. I tired the test again and this
time it worked. This average time for the
retest was 122 seconds for each 100' drop in altitude.
After completing the test Tom Driscoll showed
up in his RV-12. Tom flew down from the
SLC airport to see my RV-12 and then offered me a ride. Of course I was happy to accept. We went up and flew around the south end of
the valley for a short while. Tom let me
take the controls. What a sweet
airplane. Light on the controls and very
stable. I also did a power off
stall. It got really mushy just before
the drop. It recovered really well.
I got a picture of Tom as he was leaving. I am going to be taking some transition training
with John Albury (Jetguy on the VansAirForce forum) later this month. I am glad to have been able to ride and fly
an RV-12 before going down to Texas to fly with John.
