Below are a set of photographs that I took 10 years ago. It’s a Stits SA-7D Skycoupe that was owned at the time by Gary Coppen. In the Winter of 2002 I was just getting back in action after losing our Pietenpol. Gary showed up with an engineless Skycoupe and offered to leave it with us on long-term loan. He understood that we needed a new testbed and demonstrator, and he offered his proven airframe without cost or strings attached.
We set to work immediately and went about producing a modern Corvair engine installation. The photographs you see here are from the Spring of 2002. While some of the things look antiquated here, it’s worth noting that the layout of Front Starter and Front Alternator that we continue today is used on this aircraft. Our Pietenpol had used both front and rear starters and alternators over the years when we used that airframe as a testbed. By the time I got the Skycoupe, my ideas on installations that would serve the most builders were already sorted out. Simplicity would remain the overriding goal. Although we have continuously done research and testing, the Skycoupe in the 2002 update to our Conversion Manual marked a turning point in our work. Previous to this, our Conversion Manual was really my shop notebook filled with useful information for people working on their own conversion. The Skycoupe in the new Manual was different. The engine installation was meant to be something that builders could replicate and expect proven success from. The Manual had become more of a how-to document, giving a lot of information on building and installations like the Skycoupe, in addition to the previous material on operations and practices.
In 2003 we purchased our 601 XL kit from Zenith at Oshkosh. We had the aircraft complete and on display in the Zenith booth at Sun ‘N Funin April of 2004. Our new Zenith rapidly eclipsed the Skycoupe as the focal point of mainline testing and demonstration. The Skycoupe was seen less often but still lived in our hangar for a number of years. In 2005, we took it to Sun ‘N Fun and put it on display as our flying Turbo testbed aircraft. It served in this capacity for a long time before it was damaged in a windstorm. Several years ago, we started a restoration but it was sidelined by more pressing projects. 18 months ago, Gary reluctantly put the Skycoupe up for sale. He owns a number of other aircraft, including Corvair powered KR-2S, and he didn’t want the Skycoupe to wait a number of years until he had more time.
Today the Skycoupe belongs to Craig Anderson of South Dakota. The airframe is undergoing a much needed total restoration. Craig is headed off to Corvair College 22, now only 10 days away. There he is going to assemble and test run the new powerplant for the Skycoupe. It is a 2,850cc engine with a Weseman bearing, Falcon heads, and all of our Gold system parts. Although this engine is state-of-the-art it does directly have its lineage in the Skycoupe’s 2002 installation. The starter and the alternator are in the same orientation, as are the cooling and electrical systems. The 2,850 will have 10 more horsepower than the 2,700 engine in the photographs. With its dished pistons, the 2,850 will run interchangeably without adjustment on both 100 low lead and 93 unleaded. In the photographs, the Skycoupe was equipped with one of our then state-of-the-art Dual Points Distributors. Craig’s engine will run with our modern variant, the Electronic/Points Distributor. Overall, his engine is a series of incremental improvements, carefully thought out over a decade’s worth of work. Less than one out of 10 experimental aircraft companies survive to see their 10th birthday. We had already had 10 birthdays by the time I took the photographs you see here. We are in this for the long run, to support builders as they work towards their goals. If you have dreams and plans that involve building and flying, and they have remained important to you for a long time, then make this your year of action. The decision is up to you, no one else can make it for you, don’t let it pass you by.
Here is an overhead view of the Skycoupe’s engine installation. The Starter is the same one we use today but on a different set of Brackets. The alternator is a permanent magnet, but an early 14 amp model. The oil system is virtually stock with a 12-plate cooler and stock oil filter.
Here, a rear three-quarter view. In the foreground is an aluminum box that houses the coils, the MSD coil switcher, and the voltage regulator. They were placed here because the Skycoupe has a 20 gallon gas tank immediately behind the firewall. The 1.5 inch scat hose feeds cooling air to this box (the box had internal baffles that restricted the airflow to less than the hose size suggests), the air flows out the bottom after flowing over all the components inside. The Distributor is a Dual Points model. The oil pressure sending unit worked in this location but the temperature always read incorrectly.
Here, the Oil Pan shown here is the first Deep Sump Welded Aluminum Pan that we made. We still offer these today. I used this same motor mount layout to build several other later mounts in the shop. It also appears on Dave’s Wagabond in 2004, our Buttercup project in 2008, and on our Tailwind project in 2011. The carburetor is a Stromberg. The large hose is feeding fresh air from the cowl, the small is for carb heat. The gascolator is at the lowest point in the fuel system.
Here, on the valve cover is a Cessna 150 breather. These worked under most circumstances, but proved to be very difficult for builders to get inexpensively. With the 601, we moved to the readily available Aircraft Spruce breather. The location, however, was a winner; we have put every set of breather lines at this location since. The exhaust system is ceramic coated mild steel. These do not last compared to stainless models. The tubing size here is 1 3/8″. Testing proved that it needed to be slightly larger. The overall exhaust system layout remains fairly close to this. The goal is minimizing the amount of surface area under the cowling.
This photo shows the passenger side view. The Skycoupe was the last aircraft we built that had a bolted on intake at the head. We abandoned this when we moved to our new Nosebowlshape with the Zenith 601. If you look closely, you can see that this intake manifold is made out of many separate pieces of of mild steel. A painstaking project of gas welding. Today the intake manifolds we offer are the same shape, but are made out of a single piece of stainless tubing. This also offers a good view of the side of the cooling box. The main battery cable and the starter cable meet each other on a phenolic plate on the side of the box. Internally, they are connected to the voltage regulator. The wiring bundles are packaged in red Fiberglas woven tubing for chafe protection. The front of the baffling looks blunt because this aircraft had previously been flown on a Subaru with a belt reduction. That engine had an extremely flat face, and the baffling seen here only filled up the original cowl. In later testing, the Skycoupe was converted to one of our Nosebowls which transformed it from an ugly duckling into a guided missile.
Above: One of the last tests I performed was blocking up the aircraft to a 22° angle and chaining the tail down. We actually ran it in this position for extensive tests of its fuel flow at full power, and checking that the Deep Sump Oil Pan would feed oil at this angle at wide open throttle. The system worked very well. In 2002 I sported Burt Rutan mutton chops. Grace isn’t nostalgic about them today. These photographs were taken in front of our old hangars at the Spruce Creek airport in Daytona Beach, Florida. The hangars were built in the 1960s and were among the oldest structures at the airport. By 2002, Spruce Creek had evolved into the world’s largest fly in community, a gated location of 1,200 hangar homes.There were many good people there. Our hangars, nicknamed “the ghetto” by the real estate agents, were the focal point of lively after hours beer drinking and hangar flying. Most of the aviators in attendance were successful guys with million-dollar homes and hangars with painted floors where nothing interesting was happening. Our hangars reminded them of good times in their past when things were simpler and fun was a lot more accessible. In 2003, NASCAR driver and spruce Creek resident Mark Martin bought our whole hangar row and had it torn down and replaced with four expensive hangars that ended up housing golf carts and Prevost motor homes. The lasting important lessons that I took away from the experience was never to envy wealthy guys in aviation, a lot of them have lost touch with the most fun elements that drew them into flying in the first place, and to make sure we retained the element of good times amongst friends in everything that we did.