Panther Prototype Engine 3,000 cc/120 hp to OSH


We are 30 hours away from leaving for Oshkosh. Dan and Rachel Weseman are also heading up, and we will both be at booth 615 in the North Aircraft Display area, between Zenith and Vans. The Wesemans are bringing The Panther prototype airframe to display all the progress they have made in the few short months since Sun N Fun. Because they are good friends and we wanted to do something to support their new effort, I offered to assemble the 3,000cc Corvair that will power Panther #1. Here are a few photos of the completed engine. It will also be on display at the booth.

Above, the engine is a 3,000 cc engine with a Weseman bearing, Falcon heads and all of our Gold System Parts. The engine features some of the latest developments and a unique fuel system. The pictures of this engine are a good visual complement to our previous post on 2012 Engines For Sale. Other than the intake and the injector, this engine is the same as the ones that we assemble for builders. This engine is also an excellent blueprint for anyone building their own engine from our parts. The valve covers are one of our powdercoated sets with welded on oil filler and breather lines.

Above, a rear view of the engine. Behind the harmonic balancer is an alternator driven off the crank through a flexible coupler. It is a joint project that Dan and I have been working on. It retains the balancer and cannot put bending loads on the crank. I have never been a fan of belts on the back of the engine, but this system does not use one. The alternator is the same Yanmar unit we traditional use on the front of the engine. The set up will be flight tested after Oshkosh.

The intake is a custom stainless part made in our fixture so that it mates with our traditional welded on head pipes. On the bottom of the intake is the Precision mechanical fuel injection unit. Dan has designed the Panther to have tremendous airframe strength. The test wing took more than 9Gs at gross weight in a sandbag test conducted after Sun N Fun. Although Dan designed the plane to be easy to fly, it will be capable of impressive aerobatics. With the intention of ultimately being able to fly it with inverted systems, Dan has selected the Precision injector as his fuel delivery system.

Here is a good frontal view of the Corvair. It is only 28″ wide. This is 4″ narrower than an O-200, 6″ narrower than an O-235 and several inches narrower than a VW. The Corvair is a tough compact package. Six cylinder engines will always end up as a smaller package than a four-cylinder one of the same displacement. This view shows our new simplified adjustable starter motor bracket that eliminates the previous link arrangement. The single oil line runs direct from the Gold Oil Filter Housing to Dan’s bearing. Braided stainless hose and full flow AN hose ends look and work great but are not as expensive as people think. This hose was easily assembled from $36 in parts.

Of course Dan’s plane is going to use one of his bearings.  Originally a heat-treated casting that matched the finish of the Corvair’s cast case, the Wesemans switched to CNC machining the same design out of solid billets of aluminum. As part of their commitment to keeping aviation affordable, they did not raise the price when making this improvement. It goes without saying that this unit is entirely made in the U.S. out of U.S. material. With well over 200 of these bearings in the field, it is by far the most popular bearing. It has three strong cards to play: It is by far the lowest cost bearing, it is retofitable in the field to existing engines, and it is readily available, as the Wesemans now have them machined in large groups to have them on the shelf.

The photo is also another good look at the simplified starter arrangement. We have four-part kits for engines with Weseman bearings that consist of the new starter ear, two machined aluminum spacers and a pre-made tail bracket that allow any of our starters with a bolt on ear to be adjustably mounted on an engine in 15 minutes without fabrication or drilling. We will have these sets at Oshkosh.

Looking at the above photos and thinking about the Corvair’s well deserved reputation for strength and cool operation, it is easy to understand much of the popularity of the engine. I have been working to develop the Corvair flight engine continuously since 1989. The engine has matured tremendously during this time, but it has never lost it basic simplicity in the 52 years it has been an experimental aircraft powerplant. While others may be captured by engines sold as “new and exciting,” the Corvair remains a very popular option for builders looking for “Old and Proven.” 

I have said many times that the Corvair isn’t for everyone. We sell assembled engine just like the one above for roughly half the price of a Rotax 912, but there are plenty of people who pathologically purchase imported mechanical items. We can teach people to build a Corvair just like the one above for less than $8,000 in parts, but learning things and getting their hands dirty are alien concepts to many people who claim to love experimental aviation. For the rest of us, the Corvair is a great opportunity to have a proven and affordable powerplant.-ww

2 Replies to “Panther Prototype Engine 3,000 cc/120 hp to OSH”

  1. William, I know you’re busy with Osh, and best of good fortune there. I’m pretty excited about the Corvair, have done some car engine rebuilding of a simple nature, etc. I’m pretty partial to the CH 750 and know that’s a good combo with the Corvair. My ultimate capability for a CH750 dream plane is to have enough torque to have no problem taking off from water with two up weighing in at the ‘typical’ 170 each for a total of 340, light baggage/day trip. I’d probably build Zenith floats, maybe amphib. Let’s say take off altitude of 5000′ max, cool weather, not pushing any density alt. The question is, which of the 3 motors, 2600, 2750, 3000, makes the most sense but is not overkill? Thanks! And keep on doing this great thing.

  2. Some years later, surprised to see this comment while re-reading the article, I marvel at the lack of proofing: 2700 and 2850, of course. Now mostly 2775 ‘all fuel’ or 3000, also w/ lower compression (95 hp heads), for max reliability and fuel availability. At least WW keeps on doing this great thing. {;^)

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