Electrifying The Skyshark R/C Messerschmitt 109E

SPECS
PLANE: Skyshark Bf 109
MANUFACTURER: Skyshark R/C
DISTRIBUTOR: Skyshark R/C
TYPE: 1/6-scale warbird
FOR: Intermediate to experienced modelers
WINGSPAN: 64.8 inches
WING AREA: 719 sq. in.
WEIGHT: 10 lbs. 3 oz. (163 oz)
WING LOADING: 32.5 oz./sq. ft.
LENGTH: 54.4 in.
RADIO: Airtronics RD8000 transmitter with 92778 Receiver and 7 Airtronics 94322Z servos
POWER SYSTEM: AXI 5320-28 motor, custom 18×14 prop (recommend APC electric 18×15) , Jeti advance 90 Plus ESC, FMA Balance Pro 29.6V 8S (2S plus 6S) 3200mAh (20C) Li-Poly pack
FULL THROTTLE POWER: 49 amps, 1450
watts; 8.9 watts/oz., 142 watts/lb.
TOP RPM: 6,450
DURATION: 7 – 10 minutes mixed flying
MINIMAL FLYING AREA: large flying field
with prepared runway, grass or pavement
PRICE: $249.95
COMPONENTS NEEDED TO COMPLETE:
Motor, batteries, speed control, radio

SUMMARY

Skyshark designed this scale Bf-109
for .60 2-stroke to .90 4-stroke size
glow engines, but I decided to convert it to electric flight by installing a power system consisting of an AXI 5320-28 brushless outrunner motor, 8-cell BalancePro HD Li-Poly pack and Jeti Advance 90 Plus speed control. With well over 100 watts per pound, this classic WWII warbird offers unlimited vertical, smooth performance, and a mixed-flying duration of 7 to 10 minutes. This project is a testament to the advantages of electric power for scale warbird
applications.

THE AIRPLANE

The Messerschmitt Bf 109 (or Me 109, depending on how you interpret the historical references) has always been considered one of the classic fighters regardless of which side you happened to be on. As the Skyshark catalog says, The Me 109 was the standard by which all other fighters of WWII were judged. It served the Luftwaffe in almost every capacity, from interceptor to night-fighter to ground attack and photo reconnaissance.

The several E variants were loved by the Luftwaffe pilots who referred to them as their Emil. The 109 is considered to be the classic German Battle of Britain fighter, the deadly opponent of the RAFs Hurricanes and Spitfires. The 109 has also been considered too difficult by generations of model builders who knew better than to risk their time on a model with that narrow, spindly-looking landing gear that was a ground loop waiting to happen. The master modelers who could actually scratch build one also understood that those tiny tail surfaces at the end of a long, skinny fuselage would not work without precise and reliable radio control and pilot skills to match, and the Bf109 earned a reputation as a poor choice for even the most serious scale modelers.

EVOLVING TECHNOLOGY

It used to be that converting a model designed for glow power to electric meant replacing a lot of heavy, clunky balsa structure and lite ply with top-quality lightweight balsa, cutting lightening holes just about everywhere, and redesigning a lot of structure so you could mount your electric motor and big, heavy battery pack.
With todays readily available direct drive outrunner brushless motors and practical Lithium Polymer (Li-Poly) cells, much has changed. A Li-Poly battery can perform with a significant power-to-weight advantage over the old nickel chemistry cells, and a new generation of electric motors offers a variety of power system choices that can easily compete with the .50 to .61 twostroke, and .60 to .91 four-stroke mills otherwise recommended for a warbird of this size.

You cant fake this part you must have some experience with fast, low-wing, aileron-equipped airplanes, and you must be able to handle a tail dragger with confidence, or the 109 will bite you. That does not mean there is anything wrong with the design. Skyshark has done it right, and its Emil handles pretty much the way you would expect the full-scale airplane to behave. Once it is properly trimmed and balanced, this model will fly hands off in level flight, but you need the pilot skills to get it up there and back to enjoy the ride.

All ground handling should be done with full up elevator (stick back) so the prop blast will hold the tail down, and I have learned to hold that control for a second or so after going to takeoff power to prevent nosing over before the airplane has enough speed to give the tail surfaces authority. This is standard, full-scale practice, as is getting off the elevator as the airplane accelerates to avoid forcing it into the air too soon. While all this is going on, you will need plenty of right rudder to keep the nose pointed straight ahead, but once the 109 is in air, it will go pretty much wherever you point it.

Landings are predictable. Lowering the flaps slows the airplane noticeably and produces a slight nose-down pitch that I find just right for setting up a steep approach glide. If you are new to electric power, you must remind yourself to keep a few clicks of throttle on all the way through landing. Full low throttle on an electric job can be so low that there is no appreciable prop blast over the rudder and elevator. If you forget, itll seem as though you have no control authority left just when you need it at touchdown. With all that taken into account, my airplane lands best if I fly it onto the strip just a bit fast, tail up, in a classic wheel landing.

SKYSHARKS KIT

The folks at Skyshark R/C made the decision to break new ground by developing kits for subjects beyond the ever-popular (and ever-common) P-51, P-47, Spitfire, etc. CAD and precision laser cutting have made huge advances over the old die-cutting technology. Skyshark took a chance with a whole series of those less common and really interesting designs and all of us who love scale model airplanes are the richer for it.
The Bf 109E is not intended to meet the standards of accuracy youd expect to find at Scale Masters or Top Gun, but Skyshark suggests that with a bit of extra work, that kind of finesse is possible with its kits. I have competed at that level, and I agree. The critical factors for getting a scale kit right the outline and cross sections are pretty close.

I have been using Airtronics radios exclusively in my scale models since I began competitive flying over fifteen years ago. I can honestly report that I never have to think about my radio while I have a model in the air.

The RD8000 is an eight-channel, ten-model memory radio that can best be described as a top-end sport system. With every one of my models, whether all-out competition jobs, Demo planes like this Messerschmitt, or just the sport-scale ships I fly to relax with my friends, I take the time to set up every parameter and option in the shop using the intuitive software that is part of every Airtronics computer radio. Once thats done, I can concentrate on doing the best possible job of flying my scale models. Suffice to say that anything I want to make the servos in a plane like my Messerschmitt do, the RD8000 will handle easily.

RETRACTS AND FLAPS

The builder has the choice of completing the 109 as a fixed gear sport-scale model or including either or both of the landing flap and retract options. Building the flaps involves using several extra pieces of wing structure that are included in the kit, as well as an extra pair of suitable servos. Mounting blocks and formed wire struts for a fixed main landing gear are also furnished. The 109 flies okay with the wheels down, but for me it would not seem right to build a heavy metal fighter without retracts (Skyshark specifies the Spring-Air #704 retract system).

Skyshark has simplified things for you by designing each flap as a single piece, and for a sport-scale model, I see no reason to change that. It would be simple for a builder with Masters-level experience to redesign them for accurate appearance. The flaps work. I use them on every landing, with full extension (40 degrees) as I turn onto final approach with the airplane a bit high and then let the moderate nose-down pitch provide a steep glide that ensures just enough extra speed for a smooth round-out over the end of the runway.

COVERING AND FINISHING

Skyshark has made some of the hard choices, but the builder still has a few decisions left. Full scale 109s used sheet metal skin over an all-metal structure with fabric-covered rudder, elevator and aileron surfaces. This kit employs quality 1/16-inch sheet balsa to reproduce the metal surfaces and uses open structure exactly where the full-size airplane did. You have to decide how to simulate that fabric covering as well as how you are going to seal and finish the metal/sheeted areas.