Greetings,
This weekend, I drove down to Washington, North Carolina to fly the
Brantly B2B for a few hours. I took a "Brantly B2B Introductory Course" at
East Carolina Helicopters that was geared toward the certificated helicopter pilot.
For those of you interested, here is my trip report and some opinions I have about this helicopter. As a PPL(H) with mostly R22 time and a few hours on the B47, my experience is very limited. Nevertheless, I have to say that there are some dramatic differences in the B2B that are pretty interesting.
First, the construction of the B2B seems overdone when compared to other ships (even the B47). This ship has a LOT of heavy steel throughout the construction, but that heavy construction provided a very smooth ride and gave me a feeling of improved safety. The B2B has a high inertia main rotor system. In fact, the rotor head alone is four times the weight of the R22 rotor head.
The short rigid mast, fully articulated, eliminates any chance of mast bumping. Furthermore, zero G and negative G do not create an issue or challenge as they do in the Robbie because of the weird rotor design. Unlike other articulated helicopters, the unique multi-articulated main rotor makes ground resonance impossible because of the lead-lag found on the outboard blades (there are three main inboard blades and three smaller outboard blades).
Since this ship is so rugged in construction, I could barely feel any shudder during ETL at all. I expected the performance to be significantly lacking from a 4-cylinder piston engine with all that weight, but I was pleasantly surprised. Once airborne and in ETL, the B2B had a lot of performance and more power than I could use (even with almost 600 pounds). In fact, I found it a little TOO easy get forward air speed... very slick, aerodynamically.
The glide during autorotation was what impressed me the most. No need to do anything with the collective all the way down (even in turning auto's). Obviously, this was smoother than an R22 auto, but it was even smoother than the B47 auto! I couldn't attribute the S-L-O-W and E-A-S-Y decent to any kind of thermal since the wind sock was flat and it was cool from the earlier rain that morning. Unlike the Robbie, I even had time to make radio calls and enjoy the ride during the B2B autorotation.
During OGE setting with power exercises at 2000 MSL, the Brantly B2B barely shuddered to indicate we weren't getting enough new air through the blades. No real yaw or wild pitch changes - and vibrations seemed almost "hushed." Recovery took less effort with barely any forward cyclic at all. A second setting with power exercise to an autorotation was conducted with similar glide results as before... felt like we were doing an auto through layers of cotton balls!
Throttle management was much easier in the B2B than the B47, but I really don't have enough time in the Bell to give fair comparison. On the ground, once you brought throttle to 20", all I really had to do was stiffen my grip on the throttle during the rest of the flight with minor adjustments required for altitude changes. Slightly leading the throttle with collective seemed natural after a couple of hours.
The Kevlar centrifugal clutch is automatic, which allowed us to change passengers without shutting down (requires quick throttle chop and application of rotor brake). This was a nice feature, because you can safely change passengers without concern of any kind of blade strike. Also, the electronic trim was very easy to use during flight.
In contrast, I found the hover power requirements for the B2B a little excessive unless we were into the wind. This adversely affected our ability to initiate a maximum performance takeoff. Since we were at sea level, this was definitely disappointing. When fully loaded, it took almost all 28" of MAP for this fuel injected machine to reach ETL. Fortunately, it only takes a second to quickly gain altitude in forward flight - and then power requirements were minimal. Once we were above 40 MPH, the sleek aerodynamic design made this ship cut through the air with much more ease.
Furthermore, I found the left pedal tail rotor authority lacking. It took a great deal of left pedal to keep stable, which made me very conscious of the wind direction at all times. This is probably because the anti-torque rotors are on the right hand side, instead of left. These blades had a HEAVY spar with aluminum outer construction. The R22 anti-torque blades are of better design and provide much more tail rotor authority.
Since the B2B has oleo struts, landing was definitely a different experience. You feel the skids “touch,” but since you are on hydraulic struts you aren’t all the way down, yet. You have to continue your decent with a stable attitude and land “though the deck” before you are completely on the ground. After a little practice, I found this cushion will almost guide you in the last few inches if you get a little more light handed with the cyclic. It will definitely make slope landings much easier!
The staff at East Carolina Helicopters
http://www.eastcarolinahelicopters.com was extremely knowledgeable. The ground instruction was never boring, and the owner used to be an engineer for Brantly many years ago. They had retired parts that you could bang on without worry, which was very useful during ground instruction. It helped with the visualization, and was reminiscent of the RHC Factory Course. The CFI had about 900 R22 hours and several hundred B2B hours, so he did a great job of transition training. I had so much fun; I stayed long enough to do a little night flying in the B2B.
Finally, I would summarize my experience with the Brantly B2B as very positive, and I look forward to flying her again. There are pros and cons to every ship, and I hope I was able to express both in an amicable manner.
R2