Find out what others have said about the services they have received from Aviation Resources:
- "I know his reputation precedes him, but I have to write. Jim Barker stopped in at Pompano Air Park to balance my prop. When I bought the plane with 770 hours, it had some vibration. I bought the anti-vibration mats from Jim and that helped a lot. The previous owner had the prop done around 450 hours, so as I am almost at 900, I decided to have it done while Jim was in town. WHAT A DIFFERENCE! I didn't even realize there had been so much buzzing until I flew it the next time! He also changes the little springs and cleaned my plugs, and did like 4 or 5 other "little things" he found while lurking under the hood. Great experience and great guy to be around. Highly recommended." Steve Greenberg, Cirrus SR22
- "I can certainly attest to Jim's great work. Jim not only smoothed my plane, he found a couple of problems, including a broken airbox. My only regret is that I was not in town to help! I highly recommend having Jim do the prop balance and look at your plane." Tony Pfaff, Cirrus SR22GTS
- "Thanks so much for smoothing out the plane. The difference is amazing! If anyone else is wondering if this is useful--go for it! Jim knows the airplane backwards and forwards and is a great teacher." Dana Braner, Cirrus SR22GTS
- Excerpt taken from AOPAOnline article on AOPA's Win-a-Twin:
After AirVenture, I flew N204WT to Aviation Resources at its
location on the Cumberland, Wisconsin, airport (UBE). There, Jim Barker
and his team set to work balancing our/your propellers. Using dynamic
prop balancing procedures, it was learned that the left propeller was
out of balance by a factor of .315 inches per second (IPS). In other
words, the prop disc was wobbling about its axis at a rate of about a
third of an inch. That's not much, but it's enough to make the engine
and prop vibrate and set up unhealthy stress paths in the propeller
blades and engine crankshaft. Abnormally high vibrations can also cause
horsepower-robbing friction and abnormal component wear especially of
the alternator mounting brackets and exhaust stacks.
By bolting 29.6 grams of nuts, bolts, and washers to a strategic
spot on the crankshaft's flywheel, the vibration level was reduced to
.003 IPS. That's a 10-times reduction in vibration levels. Barker took
about three hours to do the work, using a special tachometer and
vibration sensor, plus proprietary computing equipment.
Then it was on to the right engine, and that's where the value of
prop balancing kicked in to the max. Barker saw a .539 IPS
out-of-balance condition indicating unusually rough vibrations. And in
fact, you could see the out-of-balance prop by looking at the spinner as
the engine ran. The spinner tip wobbled as it spun around at 2,100 rpm
during the ground runs used for balancing trials.
Barker's computer said to place a whopping (a relative term in prop
balancing) 96.78 grams of weight to correct for the imbalance. From
experience, Barker knew that such a large weight recommendation meant
that the odds were that the prop would never balance properly. Something
was wrong with the right engine's prop setup. Barker found out, and you
won't believe what it was.
The prop was installed incorrectly. It was mounted 90 degrees from
its proper location. Turns out, you don't just bolt a prop any old place
on the crankshaft flange. You use a reference, or index, bushing to
align the blades. In this case, the index bushing was aligned with the
top dead center mark on the flange.
The prop was removed, reinstalled in the correct position, then
dynamically balanced after three ground runs. All went well, and the
right prop's final vibration reading was .040 IPS not bad at all.
Aviation Resources also addressed some other maintenance issues
tightening the right engine's alternator belt and number-two cylinder's
upper spark plug and replacing exhaust gaskets on the right engine. The
oil was changed on both engines as well.
In all, it turned out to be a great maintenance stop. It was the
first time in 45 hours that the cowlings had been removed and the new
powerplants and props had been inspected. Guess 50-hour inspections
really are good ideas.
And I could tell the vibration levels were way down on the four-hour, 30-minute nonstop flight back home to Frederick, Maryland.
For the trivia-minded, I averaged true airspeeds in the 174-knot range
at my 9,000-foot cruising altitude, saw sustained groundspeeds at 190
knots, burned 81.9 gallons, and logged 45 minutes of actual in some of
the bumpiest clouds I've ever encountered cumulus leavings of an
aggressive cold front that pushed through the Midwest the day before. Tom Horne, AOPA Win-a-Twin project coordinator
