Monthly Archives: March 2016

Backwards Flight

I was watching the weather forecast and noticed a strong south wind would be blowing in the morning ahead of some evening storms. The surface winds were only predicted to be 10-15 mph, but at only 3000 feet would be 54 mph. This is faster than the 46mph clean stall speed of my Sonex. The clouds were also forecast to not be a problem. The winds were forecast to be strongest early in the morning, so I arrived at the airport at 5:30am and took off at around 6:00.

The winds during takeoff were a little gusty but almost directly down the runway.  I got to pattern altitude sooner than normal, but around 2000 feet started to have doubts that the forecast headwind was correct.  The air smoothed out and around 3000 feet I was easily moving 10mph backwards.  I zigzagged a bit side to side to keep an eye on what was happening on the field.

I began my descent north of the runway while still flying backwards and zigzagged intentionally thinking it would allow me to keep making progress backwards while descending into slower air.  Once back below about 2600 feet the air was turbulent again and difficult to comfortably keep the airplane close to a stall.  By this time I easily had the field made and flew a normal full flap approach at 70mph down to the runway.

backwards_flight

Once above 3000 feet, I was able to maintain altitude easily between 2200-2400 rpm. Oil temperature rose as high as 215F, much higher than it normally would in cruise. The highest CHT stabilized around 350F, also higher than I would normally expect.

Fuselage Jack

I typically use a bottle jack on cinder blocks with 2×4’s on the bottom of the fuselage to lift one wheel at a time when working on the landing gear.  This time, I needed to remove my axles to repair elongated bolt holes that seem to be causing some shimmy on landing.  For this I wanted a more stable platform.

The simplest solution seems to be cutting a sawhorse a little taller than the bottom of the fuselage and lifting the tail while someone slides it into position.  The sawhorse is either positioned at the spar tunnel or as far forward as possible on the fuselage.  I typically work on the airplane alone and briefly considered and abandoned a trick method using ropes to position the sawhorse.  I have a mental image of somehow getting stuck holding the tail up while the sawhorse is awkwardly pusitioned to dent my wing.

A popular method on the vansairforce forum involves these hydraulic jacks from harbor freight. Unfortunately, they are 24″ tall and the bottom of the Sonex fuselage is 19″.

image_17527

Scissor jacks seemed like a good solution, but I kept finding small ones intended for cars.  Securely mounting two of them to 2x4s seemed like it might be a challenge and would be dependent on the exact design of the jack.  I stumbled across these 24″ tall “leveling scissor jacks” on amazon.  They come with all the hardware needed to attach them to 2x4s and mine came with a hand crank rather than the drill attachment they advertised.  I much rather have the hand crank.  81rH7ZD2pOL._SL1500_I was easily able to lift the airplane and the airplane felt very stable.  I originally intended to attach 2×4 boards running fore and aft to the bottom of the jacks to increase their footprint, but the feet on these jacks are already pretty big so I left them off.20160227_151127