First Flight of the new 3000-pound Bearhawk Five

Source: 2020 Q2 Beartracks, Jared Yates
There is another new member of the Bearhawk family! This one is the fifth, and also the largest. This new and highly capable variant has been in the works for several years. It uses the same wings as the Bearhawk 4-Place Model B, but the fuselage, landing gear, and tail pieces are all new designs.
This particular prototype has wings that were built in the Mexico factory by Bearhawk Aircraft, back in the earliest days of the Model B tool-up. The fuselage was originally lofted by Bob’s local friend Jerry Mullins, though Jerry had lost some momentum as the years went by. Skipping ahead to early 2018, serial builder Collin Campbell had finished building his Bearhawk LSA and the vacancy in his shop had him itching for the next project. The Five made its way out to Bolivar, Missouri and just a little more than two years later, here it is.
Collin is perhaps the most experienced Bearhawk builder excluding the factory and Bob Barrows, and his experience shows in the fit and finish of this new prototype. This project required a different mindset and strategy. Collin had a set of plans, but they weren’t yet as tidy and customer-ready as we expect from finished plans. He made frequent contacts with Bob to clarify and adjust as necessary.
When it was finished, Bearhawk Patrol builder and owner Rollie VanDorn from Zanesville, Ohio, came for a visit. Rollie conducted the first flight and the first several hours of flight testing, validating the handling characteristics and initial CG envelope tests. Weather and “day job” constraints conspired to keep Rollie from testing for a little while, so Mark asked if I might be able to go fly a few hours as directed by Bob.
Under normal circumstances, Bob Barrows would be flying these first few hours. In that stage, he wants to be sure that he likes the way the airplane flies. But since he is still recovering from his ankle injuries, he wasn’t up for travelling this time. Instead, Rollie and I were his remote eyes and ears, making multiple phone calls per day to report data and establish the next steps.
When I got there, Bob wanted to validate his positioning of the CG limits, so that he could finalize the first version of the plans. Word had gotten out about the new plane, and Mark had already taken the first two kit orders. Factory tooling was held up waiting for plans, and plans were held up waiting on some test flights.
The airplane slept in the hangar at Collin’s house, where he has a short grass runway. Collin and his wife Sarah let me stay at their house in the guest room, which made life quite luxurious. I arrived via airline flight and rental car late on a Sunday night, just around dark. I hadn’t been to Collin’s since June 2018, when I stopped by to interview Collin and get photos for the Kitplanes article about his three Bearhawks. In the photo to the right from that visit, you can see the tail section of the Five, which we snuck unannounced into the magazine.
That evening, Collin brought me up to speed on where he and Rollie had left off, and we took a look at the airplane. The most enduring impressions were the build quality and the size. Having crawled around Collin’s three other airplanes to take pictures two years ago, I’ve come to appreciate the “Collin Style”. This includes light colors, clean simplicity, and a soft inviting paint texture that comes from the “Polytone-over EP420” finishing process on all of the metal parts. Something about that is just a little less harsh than the mirror-gloss of Aerothane, or the “orange-peel gloss” of Aerothane that I’ve become accustomed to on the airplane at home. As for size, the cabin is a foot longer, and the fuselage is two feet longer overall. The cabin door is quite obviously wider when looking at the side of the fuselage, and there is an extra few inches of cabin width. The wider fuselage makes the wingspan ever so slightly longer, but that’s not something that shows up in a walkaround. On the other hand, the taller vertical stabilizer, and the thicker and longer span of the horizontal stabilizer and elevator do certainly catch my eye. I’m a little extra-aware of the 4-Place tail span, having executed a wee-hours operation to tow the fuselage to an airport before the first flight, without removing the elevators. There’s no hope of getting away with that on the Five. To someone who hasn’t walked around a few Bearhawks, it might pass as a 4-Place, but I think any builder or observant Bearhawk fan would be able to sense the size difference right away.
Collin built and configured this airplane with the expectation that it would eventually become part of Mark Goldberg’s company demo fleet, so it incorporates several of Mark’s equipment preferences. The panel is minimal VFR to keep down the weight and the distractions. The interior is configured with four seats, though of course there is enough room in the cabin for a third row. If building it to be a 6-seater, the second row seat could come forward a little to sacrifice some of its cavernous legroom, which would be nice for the third row occupants. As it is currently configured, this plane is a very spacious 4-seater. Mark also selected the engine, which is a beastly Lycoming IO-580 rated at 315 horsepower. The three-blade Hartzell Trailblazer prop is the same one that I’ve flown on Mark’s Bearhawk 4-Place, and the thrust is fantastic. The parallel-valve O-540 is another less thirsty option that should still produce a nice flying Bearhawk Five, with its mere 240hp.
On the first day of flying, we were able to complete Bob’s tasks for verifying the forward CG limit. This involved incrementally moving the CG forward, with a flight after each change to verify that there was still adequate flare authority in the landing. Even at our forward-most configuration, there was plenty of elevator authority left for the flare, without needing to add power. As we moved the CG forward, the neutral elevator position became increasingly nose-up, until it reached around 4 inches at the counterbalance. The Five, along with newer Four-Place kits have 35 degrees of nose-up elevator travel. The increased travel, increased tail size, and airfoil-shaped profile all helped us reach a more favorable forward limit. Since this the first prototype, there will be some differences in the serial kits. The prototype has a ballast box in the back of the baggage area, and it isn’t yet clear whether a similar box will be required in production kits. Bob designed the heavy-duty steel box so that four separate 38-pound weights can be added or removed. Each weight is a piece of round steel bar, which you would definitely not want to drop on your toe, or anything else. Thankfully there is a sturdy handle on top of each one. Bob is always good at designing lightweight structures, but in the case of a ballast box, the design goal changes since adding weight is the goal. I’m happy to attest that he’s quite capable of designing heavy things also.
On the second day of flying we tested both the maximum gross weight, and the aft CG. This required ballast, so I started by ballasting myself with a hardy breakfast. I needed it, because with an empty weight of 1512 and a target flight test weight of 3000 pounds, there was a serious gap to fill. We used concrete mix bags, sand and gravel bags, and fuel to gradually work our way up to 3000 pounds and the
rear-most CG. While we didn’t get very scientific with the takeoff and landing roll measurements, just watching the runway lights and markings showed a takeoff roll of around 500 feet at the heaviest weight, with a climb rate of 1000 feet per minute and a fuel burn of 30 gallons per hour.
The cruise performance was very good, even at much more favorable engine settings. When I configured the engine for the same 8 GPH fuel burn that I would expect to use on my O-360-powered 4-Place, the Five yielded the same 115 mph cruise speed. This tells me that any performance penalties of the heavier weight are overshadowed by the drag improvements absent from my Model A. We find that most of Bob’s airplanes don’t suffer much of a cruise speed reduction at higher weights. At an economy power setting more fitting for this engine of 12.3 GPH, the IAS was 141 mph, CAS was 131, and TAS was 150 mph. The calculated engine output was 56% power, at 2400 RPM and full throttle, lean of peak. This is how I would have set up the engine if I was going to go somewhere with it. But just for giggles, advancing the mixture level upped the fuel flow to 17 GPH, which the little JPI calculated to be 70% power. This got an extra 13 mph on the true airspeed, but my wallet was trembling even though I wasn’t paying for the fuel. Some sort of pocket solidarity going on there. This particular plane has 50 gallons of fuel, which means there are real range implications to flying like that for long. Collin placarded these tanks at 25 gallons each, leaving a small air gap at the top to limit overboard venting. Totally filling them up to the tippy-top, they might hold a little more than 50, but might not hold it for long if flying even slightly uncoordinated.
There are much more detailed accounts of the test flights at https://bearhawkforums.com in the new channel that we created just for the Bearhawk Five. The biggest takeaway for me is that Bob has created a fantastic new addition to the lineup. I was first attracted to the Bearhawk because it had four seats, and so few homebuilts do. The payload and cabin size of the Five will open up a broader market and make available an airplane with very few peers. It was quite a privilege to get some time in the airplane, and I hope many more of you will get to experience it once it’s out of the Phase 1 period and out and about. There is much more testing and proving to do, taking the airplane out to its natural habitat and really showing what it is capable of.