Source: 2020 Q2 Beartracks
This month we’ve included Bob’s answers to two questions sent in by readers. First, Patrol builder Brooks Cone asks about making a computerized model of the plans.

Brooks says, “Do you plan to have them put into CAD, has anyone ever asked permission to put them into CAD? Is it being done by someone yet?”
Bob’s answer is a preference towards the hand-drawn plans. “I don’t have any time to do that kind of stuff, and it allows people to just put it on a disk and sell to everybody, which I don’t care too much for.”

The second batch of questions comes from builder Casey Hutson. We could call Casey an avid boater, since he is at sea for months at a time in the Navy. All of that time at sea has inspired a few follow-up questions about Bob’s ultralight. Casey asks: “I know it’s in the early stages, but compared to the LSA, what is the estimated build time from plans?”
Bob says the build time will be perhaps 10% less than a Bearhawk LSA. There are slightly fewer parts, but still about the same complexity as an LSA. In some ways, the extreme weight reduction makes the construction more challenging, with thinner materials. Fuselage finish welding has always been a demanding job that’s hard on a body. Bob says, “I was going to tack weld it and have David Spencer do the finish weld, thinking I’m getting to old for this. I was a little worried about being able to keep my hands steady enough to weld it at 77 years old. It’s turning out really good, I’m happier with my welding now than I was on the last one. Those thin wall 28 tubes came out nice.

Next question from Casey: “I know his goal is electric, but will the option be there to run a combustion engine if the builder chooses?” There are some exciting powerplant updates. Bearhawk builder Cedric Jeanty gave Bob a tip on a complete electric power package that light plane guru Chip Erwin was selling. The package may or may not be the final package that Bob flies with, but it is a starting point to get something going and help him learn about the needs of the system. The whole package was priced reasonably. Bob says “I’ll do a lot of ground tests with it, and it will get a pretty good workout on the ground before it ever goes up in the air.” Chip was having trouble with the BMS, but Cedrick has been helping Bob source a different BMS, in addition to lots of other help. Bob says “I’ve gotten a few calls from others in the Bearhawk world, and it has really been kind of fun figuring this out.”
This package has a 23-pound motor that is rated for 40 kilowatts in short bursts like for takeoff, and the battery is 7-8 kilowatt-hours and 90 pounds. The controller weighs 3 pounds and is rated at 1000 amps, oversized by a factor of two times what Bob thinks he’ll need. Getting around to Casey’s questions, a combustion powerplant would ideally be around 50hp, plus or minus 10. The weight of the engine would be crucial, and while Bob has not nailed down a final number, he suspects it would need to be under 100 pounds for the whole powerplant. As of today, Bob has built the motor mount, and is making the mold for the cowling by building up foam and plaster around the front end.

Casey has another question; like we said, he has a lot of time on his hands. “Similar to how the LSA can have a gross weight of 1500 pounds when not restricted by rules, will this be able to be classified as an LSA for those who are licensed? Basically, would I be able to build it above ultralight weights and will there be a gross weight for those that are licensed?” Bob is expecting utility-category strength at a gross weight of 550-600 pounds including the pilot. Part 103 empty weight is 254 pounds, so there is some extra margin there for someone who didn’t need to comply with part 103.

The photo below shows the parts deemed salvageable of his LSA loaded up on Mike Meador’s truck for a trip out to Collin Campbell’s house. Collin is going to rebuild the airplane with a new set of Quick-Build wings from Mark Goldberg.

Bob says his October 17th Bearhawk Fly-in is still on, so be sure to save the date! We’ll have more information in the next issue about the particulars, but everyone should visit Bob’s at least once!

More photos of the Ultralight prototype: