Corvair Motor Mount for Bearhawk LSA


Below are photos from my road trip to meet with Bearhawk designer Bob Barrows. The result is that we now have a Corvair to Bearhawk LSA mount.  While many alternative engine people apply their engine to aircraft against the designer’s wishes, I have never promoted such combinations. It is far better to work with the designer. Many designers have specific reasons why some alternative engines are a poor match for their airframes. Engine people who ignore these points are not doing any builder a favor by selling such engines to builders. They are either driven by the zealous belief that their engine is the answer to every need, or they are motivated by greed, and neither of these is a good reason for a builder to work on such a combination.


Our work with Bob on his airframe design exemplifies the opposite approach. We spoke of the combination several times over the past few years, but it was not until this year that Bob chose to closely study the combination. As I mentioned in a previous story, he is Mr. Old School and conservative, and earning his evaluation meant far more to me than having a half dozen company salesmen elect to make Corvairs an option for their builders.


Above, a look at the result. This is a factory built, deluxe Bearhawk LSA fuselage with our Corvair, sitting on the mount that Bob and I worked out in a day’s effort. The thrust line is only 1″ lower than standard to clear the Corvair’s starter. Bob calculated 1 degree down thrust, and set the engine straight in the fuselage. The engine’s datum line is 10.625″ ahead of the firewall. We set it up to accommodate our 2901S gold oil filter housing and a 2950 rear alternator. The arrangement actually uses our standard intake 3601S and the same exhaust that fits a Zenith, our 3901A. This engine has an MA3 carb on it. It is in a very good position with respect to gravity fuel flow and keeping it above the lower longerons for safety.


When we write a story, I type the words, but Grace puts all the pictures in place, because I am a moron around computers. I can move them from one spot to another, but I am terrible at downloading them from any of our cameras. As a consequence, I ask Grace to start the storyboard by putting in the pictures.  While we have 70 full camera cards of pictures, at least 1/3 of the images are of the Dog, and Grace likes to insert “Gratuitous Dog Photo” in every story.  Above, Scoob E at CC #26.  Dan Glaze taught me the phrase “Happy Wife, Happy Life”. Words of wisdom.


We had to drive away from our place in Florida at 6:30 a.m. in order to make it all the way to northern Georgia by 2 p.m. Above is the dog’s enthusiastic response. Grace felt much the same way, pointing out that “I will get to see Bob at CC #27 shortly, have fun, tell Bob we say hello.” Grace and Scoob E were real troopers on the 2,400 miles to CC #26 in Mexico, so they took a pass on this one.


Above, Bob working on the same plane, but with a Continental case. Bob’s base engine for the design is the small Continental. He used this opportunity to check his base mount on a production fuselage, and then we did the Corvair mount. Bob is a hardcore builder, and quickly shaped all the tubes in his mount. We tacked them with my 220V fine wire MIG welder. The alignment was checked many times in the process using a variety of levels and plumb bobs.


Above is the Corvair mount in process. The yellow string is the airplane’s thrust line, that is why it is offset in the main bearing bore of a spare case. The basic mount is built on one of our standard trays, part number 4202.


Above, the top view. The Corvair is 28″ wide, several inches narrower than a Continental. The Bearhawk LSA is 31″ wide. This is about 10″ wider than a J-3 cub.  At first, the number sounds almost too big, but after we made the mount, Bob took me out flying in the plane, and everything seemed just right. At first Bob just said I should go fly it myself, a great compliment I am smart enough not to accept. Although the plane flew very well with no bad habits and struck me as easy to fly, I still had a vision of becoming instantly famous in the EAA as “The Jackass who ground looped Bob Barrow’s plane.” I was very happy to let Bob do the TO and landing and the majority of the flight. The plane was the very pleasant combination of light on the controls but with positive stability on all axes.


Above, Bob on the left with his builder Rolly. He was very helpful and a great sport about letting us have full run of his hangar.


After the work on the mount was done at noon on day two, Bob packed up and flew back to his home base in Virginia. Instead of a long ride directly back to Florida, I opted to drive over and see my sister Alison and her husband Col. Nerges at their place in Charleston, S.C.  A number of builders met John and Alison at CC #24 in Barnwell last year. Above, John and I goofing around on the 3rd floor deck of their super-cool home, which is right on Charleston harbor. If you look closely you can see the Ravenel bridge in the distance. No one who is 50+ really looks good in a close-up, but it is always great to spend a few hours with family.


Funny Suburban story. Although we have just had our new ride a few weeks, it has already logged 3,850 miles on road trips. It gets about 12-13 mpg towing the trailer and is very comfortable. Every friend of ours who works in aviation thought it was neat that Northrop-Grumman was the previous owner. Many of them who rode in it commented that it even smelled a little bit like aircraft. Our friend Paul Salter, who works at NAS Jacksonville, specifically said that it “really smelled a lot like a P-3 or an EA-6B” inside. I was kind of convinced that it was the black rubber floor mats in the Florida sun. If you work on planes for 25 years, you even learn to love the way they smell.  Just this morning when I was doing a detailed clean up, I found the source. In the back, in the pocket where the 3rd seat would have been mounted, was roughly 4 ounces of Jet Fuel. In the photo above I am sopping it up with paper towels. (There was enough that I was afraid to let the Shop-vac inhale it.) Grace got a big laugh when I showed her and she said “I love the smell of jet fuel in the morning.” Happy wife, happy life …-ww.

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