Let’s look a few years ahead at a three minute flight video showing the Aircraft Tail behavior during Cruise, Landing and Side slip maneuvers. A noticeable misalignment of the Elevator and Horizontal Stabilizer occurs in these various flight control movements. An adjustment to the Forward Spar will be needed to realign these surfaces.
- Tagged airplane, aviation, elevator, experimental, experimental aircraft, flight, flight test, homebuilt aircraft, horizontal stabilizer, pilot, Piper, stabilizer, test pilot
With the tail parts re-attached to the fuse it was time to re-check control movement of the elevators, trim tab and rudder. When this checked out, the elevators and horizontal stabilizers were removed for sandblasting and priming. A strobe light bracket from Univair was welded on the top of the rudder and later wired with a quick link harness prior to fabric cover.
The vertical stabilizer remained attached to the fuse and all the remaining tail parts were then hung from the rafters until the rest of the fuse was ready to cover.
Making the tail parts require accurate welding fixtures. Plywood panels were purchased and painted flat white. Then a 2″ pencil grid was drawn on the entire face of the panels. I then transposed the full size shape of the stabilizer, elevator and rudder on the plywood panels and located each rib location, hinge knuckle, cross brace etc. per the plan. The tubing was bent using a spring and soft rubber hammer and plenty of hand persuasion. Gradually I got the metal to agree with my curvy drawing. The horizontal stabilizer had a tricky leading edge taper that required spliting the last outboard length a few inches from the end and then removing sufficient material and then squeezing the ends together and re-welding the seam back together. The seam was then ground smooth.
The metal tubes and ribs were cut to size and fitted tightly together on top of the plywood pattern. Wood blocks were used to keep everything in their place during welding. Only tack welds were used to temporarily hold parts together. The assembly was then removed and finish welded on a welding table.
Welding the thick hinge knuckles and bushings was the most difficult due to the differental thickness of the knuckle and the parent tube. It was important to keep the heat directed to the heavier wall tubing and avoid burning through the adjoining thinner parent tube. Also keeping the hinge knuckles aligned was done with sacrificial bolts that sometimes became unknowingly welded to the finished assembly.
The plans also called for small 1/8″ rods in certain end locations. This was used as a anti bending brace to avoid end deformation during the later fabric cover and shrinking process.
- Tagged aircraft, airplane, aviation, elevator, experimental, experimental aircraft, pilot, rudder, stabilizer, trim, trim tab, welding