Pitts 12 EP BP Hobbies
Small fields, little money, big excitement in a scale electric.
By Frank Granelli PHOTOGRAPHY: FRANK GRANELLI & FRANK FANELLI S
ince the mid 1990s, there has been an exciting, high-performance sport/ aerobatic airplane flying that most R/C pilots don’t even know exists.
Mention a Pitts biplane and I immediately think of the little, 17-foot span, red compe- tition Pitts Special that makes me dizzy watching it. But when Curtis Pitts was nearing 80 years old, he designed a fully aer- obatic biplane that was also a cross country machine that is easy to fly. Available mostly as a kit plane, the 22-
foot span, 2,250-pound Pitts 12 combines the best of the Special and a Cessna. Well, it would if a Cessna could climb 3,500 fpm. The Russian 620 cubic inch supercharged, Vedeneyev engine produces 400 hp so the “12” never has a vertical problem. Neither does the new BP Hobbies Pitts 12 EP. De- signed as both a 3-D and an aerobatic air- craft, this exciting 35.4-inch span airplane is true to the full-size’s aerobatic performance. The BP Hobbies’ Pitts 12 resembles its full-size kit’s inspiration in another respect; it is easy to build. One-piece wings, a slide- in stabilizer, a self-aligning vertical fin, pre- hinged control surfaces and a one-piece magnetic top deck/canopy reduce assembly time to about 20 hours. That is short for a biplane that looks as great and is as unique as this one. At 2.9 pounds, BP’s Pitts 12 can fly in any
size flying field while easily handling 10–15 mph winds. Spanning nearly 3 feet and al- most as long, this Pitts 12 is easier to see and pilot than those smaller, “twitchier”
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aerobatic bipes. Having four ailerons on two wings means it can fly 3-D without the un- sightly barn door surfaces usually required. Being short-coupled means the same for el- evator and rudder sizes which appear nor- mal rather than being giant planks hung on the airplane’s rear end. Although easy to build, there are some
things not readily apparent to experienced builders when building the Pitts 12. Also, the directions are entirely pictorial and re- quire intensive study to avoid mistakes and there are a few corrections to be made. These points will be covered as the airplane is assembled.
Equipment But first, we’ll need some parts. One of the
photos illustrates most of the equipment needed to complete your Pitts 12 EP. The motor is the BP A2814-8. This 35A outrun- ner, producing 1,100 rpm/V, should be propped to draw 350 Watts continuous. An APC 10–5E propeller arrived with the Pitts 12 but the motor’s specs. call for a 10–7E minimum. Flight tests should be interesting. The test model uses a 3-cell Lithium Poly-
mer battery but a 4-cell pack can also be used with a smaller propeller. The pro- grammable BP 60A ESC can also handle 4- cell batteries but arrives set for 3 cells. Since the ESC does not have a Battery Eliminator Circuit (BEC), BP’s Version 2 BEC (5-Amp) was spliced into the ESC’s connectors. Coro- na DS-939MG digital servos were used. Dig- ital servos are a must on performance air-
AT A GLANCE Type: advanced aerobatic scale & 3D Construction: Wing span: Wing area: Airfoil: Length: Weight:
balsa and ply 35.4 inches 290 sq. in. symmetrical 34.6 inches 2.9 pounds
Wing loading: Motor:
Manufacturer: 23.04 oz./sq.ft. BP 2814-8 outrunner
Radio: Spektrum DX6i,AR61000 SM2Rx (4) Corona DS-939MG servos
BP Hobbies
115 Stryker Lane, Bldg. 4 Unit 10 Hillsborough, NJ 08844 908-431-5603
www.bphobbies.com
craft as they center accurately. The DS- 939MG servos have metal gears and pro- duce 35 ounce-inch torque at 4.8V. They are a great buy at about $10 each. The battery pack should be in the 2200 mAh range.
Building the Pitts 12 hints First, study carefully the pictorial direc- tion booklet. While construction is standard
JULY 2012
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