Kansas Bearhawk LSA Build

[David Swartzendruber]

My LSA Quick Build Kit arrived today so I decided to start a build thread for it. Here are some pictures of the delivery. Located outside of Wichita, Kansas if anyone wants to stop and visit. I'm planning to stick pretty close to the plans in my build with the biggest deviation being the use of a 3.3L Corvair engine built following the guidance of William Wynne of FlyCorvair.

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[JayDub]

Congratulations! Looks nice, now the work begins. I'd love to stop in and see it sometime when you get further along and I'm passing that way which isn't often but occasionally. I'm interested in one myself but I need to finish the projects I'm in before I even think of starting a BHLSA.

Your last name holds a lot of history in my old stomping grounds.

Jay

[David Swartzendruber]

Jay, where are your old stomping grounds?

[rodsmith]

I think the 3.3 corvair will make a great LSA engine. Curious about the engine mount. I know Bob and WW designed/built one. Is it a kit option, available from WW, or will you have to modify or build your own?

[LSA052]

The last I knew WW had it for appox $500. Contact WW for current info

[David Swartzendruber]

The Corvair engine mount is not a kit option. It is available from WW as a special order item. He made a fixture and will build them as needed. Mark Goldberg does accommodate the Corvair engine by being willing to delete items from the kit that are not used with the Corvair and by having the vertical fin offset to the right instead of left because of the CCW turning engine.

[rodsmith]

That's great news for kit builders wanting the Corvair option!

[David Swartzendruber]

I'm behind on sharing my LSA build progress so I'll do a little catching up. Here is what is looks like currently.
Sitting_On_Wheels.jpg

The first thing I did was install the main landing gear and wheels. This meant I had to assemble the struts for the main landing gear.
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Mark Goldberg gave me a tip on how to compress the spring in order to install the C-clip. Just use a socket of the right size as a spacer and a bolt. My bolt was a little too long so I had to add some washers as well.
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Here is a view showing the C-clip in place.
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Next I drilled the flanges on the inboard side of the axles to be able to mount the brake calipar brackets. Here it is as it comes before drilling.
MountingFlange.jpg

I made a drill guide to make it easier to get the hole pattern correct.
DrillGuide1.jpgDrillGuide2.jpgMtgFlangeDrill2.jpgMtgFlangeDrill1.jpgCalipers_Installed.jpg

I'm using Matco wheels which use a shorter axle than some of the other options. The axles on my kit are longer to accommodate all options so my installation required a spacer between the wheel and the nut. Matco supplied these but they weren't quite the right length so I made some new ones. I still need to drill the axles for a cotterpin. Mark said that everyone is choosing Matco wheels so he is going to start making the LSA axles shorter for Matco wheels and no spacer will be needed.
OuterSpacers.jpgAxle_Nut_Installed.jpg

To install the tailwheel, I had to enlarge the forward hole in the tailwheel spring from 1/4" to 5/16". I did this on the vertical mill with a carbide endmill.
Tailwheel_Spring_Hole.jpgTailwheel_Installed2.jpg

[David Swartzendruber]

John Brannon (LSA plans builder) came over tonight and helped me move one of my wings into the rotisserie. I'll attach a couple of pictures of the wing in the rotisserie and also pictures from building the rotisserie.

David
QB LSA project
Wichita, KS

[David Swartzendruber]

I removed the temporary pop rivets from my bottom wing skins today and took the fuel tank out. After removing the bubble wrap from the tank, I thought I would reinstall it and start working on sight gauge and fuel line connections and routing. When I went to reinstall the tank,

• I found that the straps are too long and won't tighten up.
• Is this normal for a QB kit?
• The top straps aren't doing anything to hold the tank so I think they need to be shorter.
• Has anyone else already gone through this and able to confirm what I think I need to do?

David

[David Swartzendruber]

gregc, thanks for the suggestion. The straps already have a thin layer of rubber type anti-chafe material.

[PropMan]

David-From your photos it looks like the top straps need to be shortened. On my QB kit the tanks were not fitted and i had to fab the straps, drill the filler hole and set the height of filler neck{which is done by the length of the tank top strap).

[David Swartzendruber]

Just to close this out, I ended up shortening the top straps by 3/8". I also shortened the short section of the bottom straps by 3/4". In addition, I changed out the adjustment screws for tightening the straps from partially threaded screws to fully threaded screws. All of that combined allows it to tighten up nicely now.

[David Swartzendruber]

I completed and test ran my Corvair engine that I will be using in my LSA on Dec 31, 2023. In the last couple of months leading up to the end of the year, I did some prep work consisting of cleaning and painting some parts along with installing some items such as the ring gear and prop hub, rear oil case and harmonic balancer, and oil filter housing. I then hauled it all down to Florida to complete the engine under the supervision of William Wynne of FlyCorvair. It was a great experience completing my engine over three days alongside two other builders who were there at the same time. One of the benefits of doing the supervised build is being able to use William's test stand to run the engine using a club prop. The first run lasted 40 minutes to do some break-in on the engine.

[David Swartzendruber]

More pictures from the engine build including test run at William Wynne's hangar in Florida. This is a 3.3L Corvair engine conversion.

[Frank]

Looks like you had a blast David! What is the displacement and HP of this particular engine?

[David Swartzendruber]

Frank, the displacement of my engine is 3.3L or 200ci. That is bored and stroked from the original Corvair engine which was 2.7L or 164ci. An engine like mine was dyno'd at 132hp at 3000rpm, 119hp at 2800rpm. William Wynne's standard build today is a 2.85L which is cheaper to build and gives you 112hp.

[David Swartzendruber]

My engine mount arrived from William Wynne last week and I mounted it and the engine. Now I can start work on fitting the nose bowl and engine cowling.

[rodsmith]

I've always thought the Corvair engine would be a great fit for the LSA. Look forward to your experience with it when you get if flying. Have you decided on a propeller?

[David Swartzendruber]

Have you decided on a propeller?

Yes, I will be using a Sensenich wood propellor. I picked it up used from another Corvair pilot who changed to a ground adjustable prop. It is 64" diameter x 41" pitch. William Wynne thought it would be pretty close to what my airframe/engine combination would need. If I end up wanting to change to a slightly different size, I can probably get my money back out of this one. A bonus is that this one came with a nice padded cover for the prop and a spinner already fitted to the prop. We use the Van's FP-13 spinner with the Corvair engine.

[interstate al]

What a great experience you had! Like others, can't wait to see it finished!
I think there is a LSA in Iowa flying on a Corvair engine, but not sure if the owner is active on this forumn?

[David Swartzendruber]

I think there is a LSA in Iowa flying on a Corvair engine, but not sure if the owner is active on this forumn?

I think you are thinking of Craig Owen. Here is a link to a little information about his airplane.

https://flycorvair.net/2016/10/28/2850cc-corvair-bearhawk-lsa-now-flying/

[rodsmith]

Very nice! Too bad Craig isn't on the forum, I'm sure a lot of people would have questions for him.