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Written by Andrew Griffith
A Pitts biplane evolved
Abridged product review
Photos by the author
Read the full product review in the September 2016 issue of
Model Aviation.


Bonus video


Specifications

Model type: Semiscale aerobat
Skill level: Intermediate to advanced
Wingspan: 48 inches
Wing area: 840 square inches
Wing loading: 17.8 ounces
Wing cube loading: 7.4
Airfoil: Symmetrical
Length: 49.3 inches
Weight: 7 pounds
Power system: 525 Kv 50-size brushless outrunner motor
Radio: Full-range six-channel DSM2/DSMX radio system
Construction: Z-Foam
Covering/finish: Paint and decals over Z-Foam
Street price: $ 399.99


Test-model details

Motor used: E-flite 50-size brushless motor (included)
Battery: E-flite 6S (22.2-volt) 4,400 mAh LiPo
Propeller: 15 x 5.5 two-blade (included)
Radio system: Spektrum DX-18G2
Ready-to-fly weight: 6 pounds, 8 ounces
Flight duration: Five minutes


Pluses

• Fantastic-looking, detailed color scheme.
• Unique pin system makes wing installation easy.
• Very aerobatic and fun to fly.
• Top hatches for convenient battery and radio system access.


Minus

• Main landing gear fairing didn’t align with fuselage on my model.


Abridged product review

One thing is certain—whether it’s cutting ribbons, racing cars down the runway, or putting on one of his “high octane” aerobatic shows—Skip Stewart knows how to entertain air show crowds with his P-2 Prometheus biplane.

Horizon Hobby teamed up with Skip to make a series of models of his modified series of biplanes. The P3 Revolution is available as both an ultra-micro (UMX) and a 60cc built-up version, and right in the middle is the P2 Prometheus.

The P2 Prometheus comes in two versions, Plug and Play (PNP) or BNF. The difference is that the BNF version includes a factory-installed AR636 AS3X receiver. The BNF version is the subject of this review.

Assembly

I unpacked the model to inspect the parts and sat down with the instruction manual. Despite damage to the outer box by the shipping company—serious enough that I made the delivery driver wait—the packaging is excellent and there was no damage to the aircraft.

In fact, all of the parts are bagged in plastic and secured in an interlocking foam shipping container. All of the preinstalled control horns and other sharp edges that could possibly poke holes in other parts were covered with foam blocks. Unpacking the Prometheus was like taking apart a puzzle box, and it was clear that the packaging was well thought out.

There are a couple of areas that require glue and I used Zap brand thin and medium CA. A Phillips-head screwdriver and CA adhesive are all that you need to assemble the Prometheus. A six-cell battery and a six-channel radio are required if you purchased the BNF version.




All control surfaces use ball links for a slop-free control system. The square elevator joiner, shown here, ensures perfect alignment of the elevator halves. You can also see the carbon-fiber strips embedded in the foam to prevent flexing while under load.




The removable cockpit hatch provides access to the radio compartment to bind the AR636, as well as install the lower wing bolts and aileron servo extensions.



Flying

I noticed that the Prometheus garnered even more than the average amount of attention that a new review model usually gets on a weekend. Several pilots even commented that they were thinking about getting one, but were waiting to see one in person. It seemed the wait was over.

The Prometheus broke ground after approximately 30 feet and accelerated cleanly while climbing with authority.

A few clicks of right trim and a couple of down-elevator inputs were required to get the Prometheus flying level at 3/4 throttle. The wing incidences and the motor thrustlines appear to be well tested because the Prometheus doesn’t climb or descend with power changes.

Checking the CG, I pulled the Prometheus up in a 45° upline, rolled it inverted, and let go of the elevator. The Prometheus arced gracefully toward the ground, meaning it was slightly nose-heavy. If you like a neutral CG, you either have to run a lighter battery or add a small amount of tail weight.

Moving the battery back is possible, but difficult because of the battery strap’s location. The battery would likely end up in the area between the hatches, so it would be difficult to put the strap on even if you moved it back. With all of that stated, it flew well with the CG where it was, so I didn’t mess with it any more.

A stall test was performed from both level flight and with a slightly nose-up attitude. In level flight, I reduced power and added elevator and when the stall broke, the Prometheus fell forward. When the elevator was relaxed and power was added, the Prometheus recovered and resumed flying. With the nose up several degrees and power removed, the Prometheus will drop a wing. Corrective control and power are needed to recover. Keeping this in mind, I will make sure that I don’t flare too early for landing.




The large side area and generous rudder mean that the Prometheus handles knife-edge flight extremely well.


Next, I tested the control response at the recommended rates. As I expected, with four ailerons, the Prometheus is nimble in high rate.

Mid- and low-rates made the Prometheus more docile and although it will still perform large aerobatics and knife-edge in mid-rate, it doesn’t snap or tumble as well.

A biplane has quite a bit of frontal area and that makes for a lot of drag, so it came as no surprise that pulling the power below half meant that the Prometheus would start to descend and some throttle is required to keep it on glide slope.

If you haven’t flown a biplane before, be ready for more throttle during final approach and maintain that until the main wheels are on the ground. This is a higher-performance airplane and is intended for experienced pilots. They shouldn’t have any problems landing the Prometheus.

With each subsequent flight, I had more fun than the one before it because I was getting comfortable with the airplane. Knife-edge pulls slightly to the gear but doesn’t try to roll out, and it does a pretty high-alpha knife-edge pass.

I tried some 3-D flying, and although not its forte, it does do rolling harriers and upright post-stall flying that is more stable than what I expected of the short wings. It has enough power to hover and torque roll with some reserve power for decent pull outs.


Conclusion

Many people love biplanes—they just hate putting them together and taking them apart at the field. The Prometheus flies like a big model, but will easily fit in large vehicles when fully assembled. If you have to break it down, the unique strut pins can quickly be removed and only four screws hold the wings on, so it merely takes a few minutes to assemble or break down the Prometheus.




One of the neatest features of the Prometheus is these L-shaped pins that allow for quick installation or removal of the wing struts.


Large hatches provide easy access to the radio and battery compartments, and the top-mounted battery hatch allows battery swaps with the airplane on its wheels.

The Carbon-Z construction is sturdy and the finish is excellent. Z-Foam is tough and easily repaired with standard CA glue. Although many models replicate the overall scheme of an airplane such as this, E-flite has replicated all of the detailed sponsor logos and markings and the result is a striking model.

In flight, the E-flite P2 Prometheus simply delivers!
—Andrew Griffith
andy@customcutgraphix.com


Manufacturer/Distributor

Horizon Hobby
(800) 338-4639
www.hobbyzonerc.com


Sources

Spektrum
(800) 338-4639
www.spektrumrc.com




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