Learning Experience

This week I’ve started updating our WordPress Website.  After being away since May it takes time to get back up to speed.  But, we are making progress.

A primary change today was to set up this Blog separate from the RV-7 Builders Log.

Childhood Toy

First Model Airplane

 

 

 

 

 

 

This is my oldest existing childhood model aircraft. With too a high wing loading from it’s wire frame construction it never flew. The silk wing and tail coverings are now threadbare fragile. It hangs daily above our kitchen table in Florida. The model carries the current USAF wing roundel that was adapted in 1947.

In January 1947 red bars were added within the existing white bars on both USN and USAAF aircraft. In September of the same year, the United States Army Air Forces (USAAF) became an independent service and was renamed the United States Air Force (USAF).

Earlier, during WWII, some Kellog cereal boxes contained thin pine wooden silhouette glider models of military airplanes. Occasionally they flew well.



Globe Swift


I first flew a Globe Swift in 1961. It was a 125Hp beauty that Inga and I rented and flew from Charleston, WV to New Jersey and New York. Our baby son KJ slept behind us on the hat shelf above the baggage compartment. I was a young pilot with less than 100 hours logged. All worked out fine until the windscreen was covered in oil on departure from Syracuse. A turn back to the field and emergency declaration followed. The engine froze as we taxied off the runway. The owner wasn’t upset when told his plane was AOG Syracuse. He said he had a new engine on hand and was planning on the change. Whew!

Almost 3,000 flight hours later I went to the 2008 EAA Airventure. There was a row of smiling swift cowls, and the bug bit hard. I searched for four months and found N141PW in the hands of Pat Waters of Mt. Plesant, SC. N78314 was it’s original factory registration number. It has been a wonderful airplane and has received many upgrades since it arrived in our hangar.  Unfortunately I must now sell the plane.

Click here to see more.

Emergency Locator Transmitter

July 3, 2016

For the RV-7 we purchased an ACK-04 ELT.  It transmits on 406 as well as 121.5 MHz. and connects to Garmin G3X providing  NEMA 0183 GPS position data.  The installation manual requires the ELT be mounted parallel to the aircraft forward axis; and also recommends it be near the rear of the aircraft.  Unfortunately a rear mount would make the transmitter inaccessible to CFIT survivors.

ELT ON TUNNEL COVER

I have chosen to mount the ELT on the tunnel cover forward of the seats.  While this may increase the risk of ELT damage in a CFIT, an impact of that magnitude would likely eliminate survivors.

TUNNEL REINFORCEMENT

Another recommendation is that the mounting provide deflection stiffness so spatial movement is no more than 0.1 inch under a pressure of 100 pounds.  The pictured reinforcing channels do that.

ELT AND FUEL BOOST PUMP & FILTER

The electric fuel boost pump is mounted on a separate section of tunnel cover.  An additional cover over the pump & filter will separate them from the ELT.

Autopilot Pitch Servo

June 20, 2016

The Garmin autopilot pitch servo is furnished with a mounting plate and specific instructions for installation in a Vans RV-7.  The plate becomes riveted to the center floor rib behind the baggage bulkhead.  The servo moves the elevator push-rod via its connection to the bellcrank.

Care is given to adjusting the length of the servo to pitch bellcrank connecting rod so that no over-center lockup can occur.

INSTALLED SERVO

Wires from the db15 socket connect the servo to both the instrument panel autopilot controller and to the pitch trim servo located in the left elevator.  Torque sensors in the pictured servo generate signals fed to the pitch trim servo.

 

 

Flap Position Indicator Bracket

June 5, 2016

INDICATOR MOUNTING BRACKET

The flap position sensor is a Ray Allen POS-12.  The long arm slides in and out of the body changing the electrical resistance of the unit.  A linkage to the motor driven flap actuating arm controls its position.  The flap position may be displayed on the G3X screens.

Magnetometer Install

May 29, 2016

The Garmin G3X magnetometer feeds magnetic heading signals to the ADAHRS units, obviating the need for a whisky compass. It can be mounted anywhere distant from aircraft magnetic fields. Many builders place them in a wingtip or tail assembly.

I fabricated a mounting plate and riveted it to the upper fuselage longeron and aft side of the baggage compartment bulkhead.  The magnetometer mounting ring is shown clamped to the mounting plate.  It is being marked so the front/rear axis of the magnetometer is parallel to that of the aircraft.

INSTALLED MAGNETOMETER

Mount the Tail Feathers


May 24, 2016

Dolly and I built the horizontal and vertical stabilizers & the rudder and elevators (the empennage) during the winter of ’14/’15 in Florida.  The parts were wrapped in blankets, hauled to Michigan and have been sitting on a shelf waiting for today.

The entire process of mounting the empennage, adjusting balance weights and travel stops, installing and smoothing fiberglass tips and connecting controls lasted until July 1, 2016.  Other non-empennage tasks were also completed during this interval.

MOUNTING THE HORIZONTAL STABILIZER

We were careful to align the HS with the fuselage, measuring from the tips to the same rivet position on each side.  Then, drill and bolt.

THE HORIZONTAL STABILIZER MOUNTED

It was necessary to trim the rear outboard skins of the HS to allow clearance for the elevator balance arms.  The elevators were temporarily attached.  Then the elevator control arms were drilled for a center pivot and the push/pull control rod connections.

Dimensions:

The vertical stabilizer was mounted with it’s tip to elevator tip distance exactly 62 1/4 inches on both sides.

Elevator travel was measured as 25 deg. up and 27 deg. down.  Later, after adding stops and adjustment the final measurement was 28 deg. up and 21 deg. down.

When the rudder was installed with stops, it’s swing was set to exactly 35 deg. right and left.

May 27, 2016

Van’s plans call for trimming of the lead counterbalance weights that are installed in each elevator balance arm.  Our band-saw wouldn’t do it so I jury rigged a clamp and hand saw.  ~10.6 ounces of lead was removed.

TRIMMING THE BALANCE WEIGHTS

The Right elevator balanced OK per Vans criteria, slightly elevator nose heavy.  Addition of the electric pitch trim servo overbalanced the left elevator tail heavy.  More weight ~2 oz. was put back into the left balance arm.

LEFT ELEVATOR BALANCE ARM

The above photo shows the pink slab foam, 0.17 lead shot pellets and a portion of the large lead weight epoxied into the left elevator balance arm.

BOTH BALANCE ARMS BEFORE FLOODING WITH EPOXY

After an initial layer of epoxy, both arms were leveled to the top of the aluminum with a micro-bead epoxy paste, and then sanded smooth.

VERTICAL STABILIZER AND RUDDER TIPS

As received, the Vans fiberglass tips did not align well.  These photos show how much epoxy/micro mix was added to the HS tip.  The pen lines outline the rudder area next to receive micro.

OLYMPUS DIGITAL CAMERA
The rudder was held in alignment with the wired wood strips.  NOTE the VS tip is screwed to nutplates in the fiberglass tip while the rudder tip is pop-riveted.  This is to accommodate a vertical stabilizer taxi guidance camera in this conventional gear aircraft at some time in the future.

While installing the rudder lower fiberglass tip, I also installed an AeroLEDs strobe tail light.  The strobe driver is fully contained in the tail light.  It will later be wired to synchronize with the wing strobes.