Flippin’ Airplane – March 28th 2013
So we left off the last post with a teaser for the bottom cowl. I need to get these pages caught up…
In the last post, we were still working on little bits and pieces until we were ready to flip the airplane upside down. In order to make a new lower cowl and the various scoops and inlets, it is much easier to work on things with the airplane upside down instead of overhead with all the sanding debris falling on your face. This presents several problems, however.
In order to make the lower cowl, the wings really should be on the airplane since the outboard cowl fairs into the wings. Additionally, the engine should be on the airplane to ensure you have at least minimum clearance between every part of the engine and the cowl. So we have to flip the airplane with the engine mounted, and then once the airplane is flipped and in place, we have to mount the wings upside down.
Now my winglets are already installed, so that further complicates things. The winglets are 4 feet tall, so the airplane has to be elevated off the ground in order to get the wings on the airplane. This airplane flippin’ is definitely a multi person process. Luckily Jon, Greg, and Kevin were up for helping. Thanks guys!
We pre-built a set of four saw horses out of 2×4 lumber to support the airplane once it was upside down. We measured, but also WAG-ed the height required. The airplane was flipped by supporting the prop extension with a engine hoist and ratchet strap, while two people rolled the airplane over by grabbing the strake. The nose was on a set of cushioned pads on the ground. Once inverted, we then lifted the nose of the airplane by putting a 2×4 under the longerons, extending 3 feet outboard of the fuselage and had one person lift each side. We were then able to slowly move the airplane back into the garage, into position and lift one end (aft/forward) onto the center saw horses.
As it turned out, we had the airplane up about 5 inches higher than we needed and had to take the tires off the airplane to fit it in the height of the workshop. We finished the inverting of the airplane, and decided to lower the saw horses another day. Lowering the saw horses was pretty simple, we just supported the inverted airplane temporarily, removed one saw horse at a time, and cut off 4 inches off each leg.
Putting the wings on upside down was a very simple process, and went very quickly. It was apparent that we would need a place to sit while working on the bottom cowl. A scaffold system was built to help facilitate our work.
Sorry I don’t have many photos of this process. It was disconcerting to have the airplane upside down supported by a Harbor Freight engine hoist and a ratchet strap, I didn’t want to take any longer than absolutely necessary to get the airplane firmly supported.