| Observations:
First Flight --
As RV-4 Chase plane pilot and EAA Tech counselor Jack Hill
said. "It ain't no Cessna". When the power was added for takeoff
it
was quite a ride. Acceleration was VERY fast and liftoff occurred
in just a few seconds. Climb was like an elevator! I did
not
look down to see what the vertical speed was.
There was lots of noise from the canopy vibrating against the
fuselage.
This will have to be dealt with.
2/25/01 -- Observations after three flights:
The canopy noise was tamed by attaching foam weather stripping
inside the rear canopy skirt at a point where it seals without pushing
the
skirt away from the turtledeck. I will try some felt along the
sides later.
Gauges, Gauges, Gauges..... EGT, CHT and OAT gauges from
Westach all seem to be terribly inaccurate. Seems you get what
you pay for. I should have bought better quality gauges as they
will be a
bear to change now. I am also having some trouble with the "Vans"
gauges.
The tachometer failed on the third flight and the fuel pressure
indication can be changed substantially by tapping on its transducer
(not good...). Other problems with the "Vans" units are bad parallax
caused by their deep indentation for lighting and internal fogging when
the temperature changes.
The baffle mounted Positech oil cooler for the 0-360 seems to
be keeping the oil at a happy 190-195 degrees. I am going to
calibrate the gauge and sender to see if it is true....
The Navaid autopilot works great right out of the box.
It
tracks the localizer brilliantly.
The right wing is heavy, but can be trimmed out with the
aileron trim. I suspect it is the slight misalignment of the
right wing tip. As other builders have reported, the airplane is
nose heavy
when flying solo. This is only noticeable on landing and should
prove
to a benefit when it is all loaded with a passenger and heavy gear
behind
the pilot someday.
2/28/01 -- 6.3 hours
Landing: It is an easy airplane to land. I find wheel
landings easier because it is hard to get the nose up enough for a good
full
stall at the solo forward C.G. Much more runway is required,
though.
Preliminary Data: power off stall clean 55 KIAS, dirty
50
KIAS. Top speed without wheel fairings at 6500' 166kts TAS. There
is
a good buffet before the stall and a definite break at the stall.
It
has very little tendency to drop a wing at the stall, however.
3/10/01 -- 15.1 hours
Added wheel fairings, gear leg fairings and lower intersection
fairings and gained 10kts making the top speed at 6500' 176 knots
TAS.
The upper intersection fairings will hopefully add a knot or two
bringing the speed up to what Van advertises.
The airplane does rolls effortlessly and beautifully...
The OAT probe will need to be relocated from the pilot's NACA
duct on the front left side of the fuselage. It reads high there
from engine heat swirling up to it. The passenger NACA duct under
the right wing will be tried next.
4/10/01 -- 42.0 hours
Completed the test period and received the final Airworthiness
certificate.
Celebrated by flying and visiting friends in lovely San Luis Obispo, CA.
Was able to cure the heavy right wing by pinching the trailing
edge of the aileron on the left wing. This is a very delicate operation
as a little pinch goes a long way. I may have overdone it a
little....
Fabricated upper intersection fairings using the clay mold
method.
Speed gain was 2 knots bringing top seed at 8000' to 178 kts or 205
MPH.
The Van's gauges seem to be working out OK. The tach
returned to service miraculously and has been working fine since.
Oil
temp was calibrated with boiling water and a candy thermometer and was
very accurate. As other builders have said, CHT spark plug ring
type
probes are inaccurate. I calibrated my CHT probes with a better
screw
in type probe and found the following: Two were in error
+40°F and two were +15°. They were consistent in
their
errors, however.
Cruise temperatures are as follows Oil temp - 180-190 at 70
PSI,
CHT runs 350-360, EGT peaks at 1525-1575 (not calibrated).
4/23/01 -- 52.8 Hours
Full stall landings are easier with passengers as the C.G. is
moved aft of the forward edge of the envelope. The Oil temp got
up
to 225° F after landing and a lengthy taxi in Palm Springs, CA. The
ambient was over 90°F. Fuel consumption seems to be around 9 GPH
running at about 70%.
8/8/01 -- 120 Hours
The plane is operating mostly trouble free. Flew to
Seattle, Reno, Denver, Los Angeles and Many other shorter trips in the
last
hours.
Squawks:
- The UMA mechanical Manifold Pressure Gauge is slowly
filling with fuel. It is being replaced with a "dual diaphragm" type
gauge which separates the indicator from the inlet line and
aneroid.
- The Van's oil pressure gauge is acting flaky. Could
not find a loose connection so I might have to replace the gauge or
sender. I hate buying things twice.
- The fuel sender cover plates were leaking slightly around
the attach screws, I was able to re-seal them with Fuelube.
- The flap motor stopped working. Taking the
two screws out of the top of the motor made the brushes and armature
accessible for cleaning. Both were pretty gummed up with
grease.
Seems to be working for now.
- I still have to find a way to reduce the amount of oil
running down the belly....
8/30/01 -- 140 Hours
Pictures "Around" Mount Shasta
Re-crimped a good quality terminal on the oil temperature sender wire
and routed the wire away from the spark plug leads. Seems
to have solved the oil temperature indication problem....for now...
The new hinge pin above. A
nutplate is riveted behind the flange to accept the screw.
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11/10/01 -- 164 hours
I discovered something that should have been obvious.
The Stewart Warner engine gauge sending units must be grounded,
duh! Mine are mounted on the engine mount with cushioned clamps
and attached to the engine with flexible -4 lines. The
flexible lines were providing a
flaky ground at best, adding some nice white teflon sealant on
the
pipe thread fittings turned a bad ground into no connection at all.
There
is no place to properly attach a grounding wire to the sender.
The
Fix: The end of the ground wire was stripped and a hose clamp was used
to
secure it to the case of each sending unit and provide a proper ground.
The
oil and fuel pressure gauges are working perfectly now. I retract
all
my negative comments about the operation and reliability Van's
gauges.
Ground each and every sending unit including the tachometer transducer
and be happy.
Service Difficulties -- Both of the rivets on the
inboard edges of the bottom cowl attach hinges failed. They have
been drilled out and replaced with -4 rivets now. I believe the
cause of this
is the tension put on the hinge by the somewhat spring loaded retaining
method used for these short 6" hinge pins. To remedy this new
pins
were made that have a loop for a screw to attach them into the short
vertical flange instead of flexing them and popping then into a hole on
the flange. Another good method might be to avoid using hinge in this
area.
Instead, use screws into nutplates on an extended fixed flange attached
to the bottom of the firewall.
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Carb Airbox Mounting Plate Cracking
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9/22/03 -- 526 hours
During routine maintenance I found severe cracking on the carb airbox
mounting plate. The aft attach area was completely separated and
the forward two holes each had large cracks (marked below). A new
plate was fabricated larger washers were used to distribute the load.
Also, a support bracket (see picture below) was added from the
carb
attach bolts to the most forward bolt on the airbox. We'll see if
this helps....
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The new Vetterman 2" exhaust system
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I also added the new Vetterman 2"
exhaust system. The pipes are 2" in diameter from the ball joint
aft on both sides. The plane was one of the test platforms for
the new system. It seems to add a knot or two to the top speed by
allowing the engine to produce slightly more horsepower to a higher
altitude.
It is recommended given the choice between my original Vetterman
system and this one.
Also visible in this picture is the brace added to support the
carb air box.
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Bypass Door Installation
Bypass Door riveted Closed
Note the Microswitch used to monitor the status of the Door
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7/1/04 -- 651 Hours
Van's FAB Filtered Airbox Filter Bypass Kit
After reading about the induction ice accident experienced by an RV-6
it seemed installing the FAB bypass kit from Vans was a great idea.
It is basically a flap in the bottom of the airbox that is held
closed by
a strong magnet. If enough suction is developed in the airbox the
flap will open allowing air into the carburetor without passing through
the filter, i.e.; an ice or bird covered filter element.
A phone call to Vans had the free FAB bypass kit in the mail.
Part I: The bypass kit was installed per Van's
instructions and after the first test flight I suspected problems.
There was
no longer a manifold pressure drop when the carb heat was applied as
before and the manifold pressure seemed lower for a given altitude than
before.
To verify these observations a switch from Radio Shack was added
to
the door and wires run into the cockpit to sense the position of the
door.
As suspected the door was opening during high air demand
situations
such as takeoff and turning the carb heat on.
Part II: To solve the problem I adjusted the
position of the magnet to better hold the door closed. Another
flight test revealed the same problem just at slightly higher power
settings than before.
Off the cowling comes again for another magnet adjustment. This
time Two magnets were used instead of one which doubled the pulling
strength. The next flight test showed some improvement but the
door still opens at manifold pressures above 26" and at high altitude
open throttle situations. Each time the cowling goes on and off
paint is lost. This is starting to anger (and other choice words)
me.
Part III: I have decided a magnet is not the
proper way to control the operation of the door. I suspect that a
strong enough magnet to prevent the door from opening when it is not
supposed to would also prevent the door from opening when it is
supposed to. This left three other options-
1) A cable controlled door like the carb heat door.
2) An electric Solenoid pulling a pin to allow the door to open.
3) Riveting the door closed and being damn sure to get carb heat on as
soon as any contamination could enter the intake and hoping never to
ingest a bird.
Option one and two were ruled out because they add too much weight
and complexity for a "maybe situation". So, the cowling goes
on and off one more time and the FAB bypass door was riveted closed.
Conclusion: What a waste of time!! DO NOT
install!!
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6/17/05 Auto Fuel
To try to save a few bucks I have started burning auto fuel. This
is an idea I have been considering for a long time that has been
jumpstarted by expensive gas prices. I was on the verge of buying
an expensive
transfer tank and pump to move 50 gallons of gas from the local "cheap"
gas station to the airport when I decided to call Van's to get their
opinion. After a lengthy and valuable discussion with one of the
"High Up"
folks at Van's Aircraft, I was told Van's does not condone the use of
auto
gas, but, personally he does use autogas.
He told me about the real potential of vapor lock with autogas on a hot
day and a harrowing personal experience to back it up. The
solution he uses is to fill only one tank with autofuel, and only use
this tank at low power settings in cruise flight. All takeoffs
and climbs are made on 100LL.
My procedure: Purchase three 5 gallon containers of autogas on
the way to the airport and top off the car from the same pump.
Use the lowest (87) octane available since detonation is unlikely
at low (65% or less)
power settings. Strain the fuel from the gas cans into the left tank.
Taxi, takeoff and climb to altitude on the right (100LL) tank.
Switch to the left (Autogas) tank at cruise altitude. To
ensure the next
takeoff will be using only 100LL, switch to the right tank twenty miles
from the destination to allow about a gallon of 100LL to flow through
the
system prior to landing. I am hoping this is enough fuel to purge
the
system, including the carburetor bowl, of Autogas.
Observations: So far, all I have noticed is some extra money in
my wallet. In Northern California Autogas is 80-90 cents per
gallon cheaper than Avgas. The fancy EGT gauge and other engine
instruments show
no difference when burning the Autogas. I have not yet checked
the
spark plugs, but expect a reduced amount of lead deposits.
Update 2/4/06
This procedure has been working great! Roughly 65% of fuel burned
is
now 87 Octane autogas resulting in a savings of $5/hour! The only
observable change is the EGT's peak (maybe) 10-15 degrees higher with
the
autogas than the 100LL. There is no measurable performance change.
Update 11/10/06
After another summer of flying on autogas here are a few notes:
1) CHT's also run roughly 10-15 degrees F hotter on the autogas.
2) Spark plugs have much less lead in them when cleaning time comes.
Update 5/4/07
The ehthanol finally took its toll. The sump drain started
leaking on the tank with autogas. It seems that the Safair sump
valve o-rings are not compatible with the ethanol in car gas. A
call to Safair confirmed this and they kindly mailed me two "Viton"
o-rings which seem to do the trick so far. Removal of the
old rubber o-ring yeilded a cracked and dried up mess of an old
ring. Note: servicing sump valves in tanks full of stinky car gas
is no fun! If you have ever done this you already know....
Per advise from Exhaust Master Larry Vetterman, 1 oz. two-stroke engine
oil will be added to each five gallons of autogas to improve valve
lubrication from now on.
Update 4/27/08
Now three years and several hundred flight hours have past since
starting to use the ethanol laced autofuel here in California. So
far so good! With Avgas at $5/gallon and Auto fuel nearing the
$4/gallon mark, this is a big deal.
Funny autogas story: Last winter there was a very strong
north west wind aloft while heading down the coast to visit friends in
San Luis Obispo. At 17,500' there was a 75 knot tail wind
yielding a 225 knot groundspeed. ATC was contacted for flight
following.
ATC: "What kind of engine have you got in there, a turbine?"
Me: "Nope, an O-360 out of a 1962 Mooney burning car gas."
ATC: "Oh, premium?"
Me: "Actually its the low octane stuff from the cheap station, I'm only
making 49% power up here so there's no chance of detonation. I'm
seeing 40 Miles Per Gallon right now"
ATC: "I learn something at this job every day."
Continental flight Crew: "So cool."
This is only possible in a homebuilt, I thought. Home made Oxygen
system, non-certified electronic ignition, ethanol laced car gas, and
most importantly a light and efficient plane not encumbered with FAA
requirements. "So Cool!"
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Enter your state's letters to see what excessive car gas price you will
enjoy paying next time you fill up.
To be overjoyed click and see
your local AVgas prices.
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11/10/06 - 1025 hours
I learned
about homebuilding from that
It all came to a head last week when flying on an IFR flight on an
airway that runs just off the west coast to avoid the SFO terminal
airspace. A routine scan of the gauges showed the oil pressure
around
40 PSI. My stomach tightened as I thought, "Not here, not
now....". I
was seven miles offshore from the rocky coastline at 6000' above a
solid overcast.
Now my eyes were glued to the gauge and instinct started banking the
plane toward the shoreline. I was about to declare the "E" word when
the oil pressure climbed back to ~60 PSI. All other indications
sounds and smells were normal. It must be an indication problem,
I
decided. I continued the flight another twenty minutes to the
destination with a visual approach. After landing, no loose
connections were found at the transducer or the gauge. Hmmmm???
Electronics 101. As noted in the entry dated 11/10/01 (exactly
five years ago), I solved some oil pressure indication problems by
properly grounding the pressure transducer. Since that time the
indication has fluctuated. Initially the fluctuation was only a
few PSI, but this has gradually increased to a 15 PSI fluctuation
recently.
At 3:52AM that night I woke up, my mind racing through the scenario and
possible causes. How and why? Then I remembered I had wired
both power and ground to all five of the Van's Engine Instrument gauges
in series. In my electronic ignorance, I had "daisy
chained" them together. Seemed a neat and tidy way to go at the
time. NOT GOOD.
When a ground is not really a ground, AKA wiring in series.
Before the next flight, I
connected the oil pressure gauge ground in parallel and saw the most
solid oil pressure indication since the plane was new.
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What I imagined the would be found at the bottom the Pacific with me
still strapped to the seat. (Note this is a file photo from the
internet)
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12/6/06 - 1035 hours
The tailwheel was getting pretty worn out and I happened to notice the
cool new 6" pneumatic tailwheel available from Matco - http://www.matcomfg.com/.
The tailwheel chains were replaced about two years ago with the Rock
Steering Link which has performed great so far. Now, the old
Van's wheel and tire were ruining the neighborhood and I must have had
sixty (extra) bucks burning a hole in my pocket. With spacers and
axle sleeve it cost $95 plus $10 shipping to the door.
Installation: The only tricky part is it uses a 1/2" axle instead of
the 3/8" axle use with the Van's wheel. I did not want to drill
out the fork to 1/2" for two reasons. 1) In case the Matco wheel
did not work out, 2) So the towbar would still fit over the olt end and
nut.
To solve this
problem, some 3/8 ID - 1/2" OD bushing material was purchased from
Aircraft Spruce (P/N 03-16900). A
bit of work is
required on the bushing to get the axle through it and to get it to fit
in the sleeve supplied by Matco. Also, some AN960-8 regular and
light washers were needed to get the width to match the fork because
the spacers provided were not quite wide enough.
The Van's wheel has a diameter of about 5-5/8" while the Matco wheel is
6". The Matco tire BARELY fits in the fork. But is does
fit. I have done five landings with no rubbing so far.......
Observations:
- Looks Cooler
- About One pound
Lighter
- Has high quality
sealed bearings
- Tire and tube can be
replaced for $16 + shipping
Update 5/4/07 - 1087 hours
The Good-----
The new tailwheel is working out well. It rides and handles
better that the Vans unit.
The Bad-----
I suspect, however, the tire life will
not be nearly as good as the solid Vans tailwheel. If this one
last more than 250 hours it will be a shock. The Vans tire lasted
over 1000!
The new wheel does seem a bit light duty for the task, especially when
the plane is heavily loaded. Matco publishes a spec. of 660lbs
static load and a 1980lb load limit. Hope not to pinch the tube
and have
a flat somewhere out in the sticks......
The Ugly----
In the tailwheel there is a little pin that comes out to keep the
tailwheel engaged with the rudder. It seems to have worn out
allowing the tailwheel to caster during landing and takeoff. This
can make for some exciting ground handling characteristics! This
was discovered at the rather windy and gusty Lee Vining California
(O24). As a temproary field fix, the pin was flipped inverted
until a new one arrives. New pins can be had from Vans for
$6.51. Part number WD-102C.
Update 4/27/08 - 1223 hours
My suspicions about the durability of the little tire came to
fruition. After a landing in Yearington Nevada (the middle of
nowhere) enroute to a vacation in Steamboat Colorado, I discovered a
flat tailwheel. The tube had been pinched. I chocked this
up carrying a heavy load and perhaps to a slightly under inflated
tire. It was Friday morning, what to do.....
I decided to fly with the flat. It would require two landings
until we could repair the tube. As fortune would have it,
Matco is located in Salt Lake City, Utah so we could stop by on the way
home and buy (and install) a new tube. They were very helpful and
accommodating and even gave us the factory tour. The tire was
destroyed by the two landings but the wheel was fine. All fixed
up with an extra tube in had, all was well again, for now....
Fast forward to our trip to Baja. We were returning and
encountered a VERY strong crosswind at San Felipe, a required stop to
depart Mexico. The landing and departure went ok, but on arrival
at Calexico to clear US customs, there it was again, a flat tailwheel
tire. That sealed the deal, back to the industrial caster
supplied with the kit. It's too bad because the little tire handled
much better than the solid tire and looked great too. Further
research revealed the tire is only rated to 250lbs. No wonder!
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Matco 6" Pneumatic Tailwheel

View on the way down to Baja
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