Electric conversion of this Sopwith Camel was easy and fast. While the model's design was predicated on strength and glass with little regard to weight, the utilization of electric power allows the plane to be displayed and demonstrated to some degree without tying up the very fuel engine usually required in the construction of a subsequent project.

I think I'll probably convert most of my planes in this way when they're not actually being fuel-flown. Their static display weights are more in line with being hung on strings, and they're not leaking nitromethane onto our carpets. Plus they're fun to play with.

Disclaimer Electric conversion of this airframe has been done for display and self-educational purposes. What you see here, admittedly, will not perform acceptably, and I don't claim that it will. Thus, I can't claim that this is an electric airplane. The very first criterion I would apply to any true claim as such would be an acceptable positive rate of climb. In order to get there, using the motor and battery group shown, I would require 9 cells (which pushes the temperature envelope a little, but it's doable) and most likely, the elimination of the ESC, since I would be running at or near 100% throttle just to keep the craft in the air.

In fact, using the motor and battery group shown, the plane would require a maximum empty weight of under 7 ounces to perform "acceptably". Obviously, a 28" plane built for a .15 fuel engine is going to be so beefed up that a ready reconfiguration between fuel and electric won't produce equivalent aircraft.

Nevertheless, I believe that anyone even remotely interested in electric conversions should go through this exercise. And I can't emphasize enough how helpful MotoCalc can be during such playtime. If you never spend a dime on software again, at least purchase this program; it is so worth it! You will begin to garner an appreciation for the distinctions between building for fuel and building for electric. Personally, building for fuel suits my personality, as I enjoy adding details and finishes most likely unsuited for properly constructed electric aircraft within my budget.

That said, I offer you the following conversion, performed in the spirit of my further development as a modeller, and in an attempt to provide an alternative to an empty airframe once I needed the engine for another project...

Removing the fuel components in anticipation of conversion to electric: note that the Hitec on/off switch has been removed as well. Another switch replaces it since the connections were sufficiently different to warrant building another harness. Note also that the throttle servo has been removed. While there could have been something new for it to do in the electric version, the electric throttle is on Channel 5 now. Since the ESC has a battery eliminator, the Hitec battery pack is also removed. The prop shown is 8x4. The electric prop is 7x3. The motor mount is shown in the foreground. The electric mount uses identical bolt pattern and the same mounting points. The fuel tank shown is a slant style Sullivan 2 ounce. The current project, a Guillow F4U-4 Corsair is upgraded to a 4 ounce version of the same tank.

Close-up of the fuel motor mount shows a custom firewall with a Dave Brown glass filled nylon mount embedded in the center and resin'ed. The firewall's color is a gold acrylic applied prior to resin. The resin itself has been left natural, neither sanded nor painted.

Photo of electric components hanging out of the airplane. Notice the two (empty) three-cell removable battery packs, themselves cut down from four-cell packs as procured at Radio Shack. The on/off switch has been placed between the two packs and located on the bottom hatch as illustrated in the fuel version description. Each of the packs slips vertically into the hole in the firewall. The speed 400 engine is embedded in a cylindrical motor mount as shown below. This prop is a 7x3, chosen primarily because it was the smallest one at Hobbytown. If a smaller one happens to be found, it will probably find its way onto the airplane. [In fact, MotoCalc'ing the scenario suggests that a 6x4 prop is the most efficient for this application.]

Changing batteries entails unscrewing four motormount screws, pulling the engine/mount away from the cowling, pulling the two battery packs out, and changing the batteries. Removal and replacement takes about five minutes. It really doesn't pay to make this a faster operation simply because the expended batteries themselves require a couple of minutes to cool down for handling (although they're not actually "hot" like some implementations - they're more like "warm" compared to most that I've seen. They actually get hotter during recharge than during discharge.)

An extreme close-up of the firewall hole leading into the fuselage with the various connections that hang out when changing batteries. The plastic-covered component at the bottom of the photo is the ESC. There is enough room in the cavern shown here to accommodate the two battery packs with the ESC in the middle just behind some holes in the electric motor mount for ventilation. All of this sits forward of the aileron servo which occupies the middle of the fuselage. The shelf for this servo is seen in the back of the depicted space running horizontally across the photo. The black-and-red plug shown just at the entrance (to the left) is the battery pack connector; while not necessary to unplug during battery changes, it was utilized to help test different battery arrangements.

Current implementation includes six 1.2 volt 1600 mA Radio Shack nickel metal hydrides in series to a six-volt motor. These batteries work just fine but require a series of discharge cycles under load before they start working as a broken-in crew. I know there's alot of interest in these batteries, and I feel confident in their abilities; but they require care and some understanding before they're up to this application. Your milage may vary.

Extreme close-up of the electric motor mount hanging loose under the plane while a new batch of batteries was being recharged. This is a view of the bottom of the mount; notice the "v" notch running lengthwise on the bottom for ventilation. The motor is seen through the notch. This cylindrical mount serves the same purpose as the Dave Brown fuel mount shown above. It encases the engine in this case and attaches to the electric firewall as shown. This assembly was constructed of plywood for flat surfaces and balsa for the curving cylindrical surface. The entire assembly was then resin'ed and painted with black acrylic. The flat round surface that caps the cylinder was painted with gold acrylic prior to resining (not visible in this photo). A custom prop hub was fashioned from nylon and glassed onto the motorshaft; it is there for the duration and cannot be removed. The prop, however, is simply screwed onto the nylon hub and can be removed easily.

So while the cowling maintains its ready fuel-conversion capability, the rest of the effect is more scale and lifelike than a honking model fuel engine busting out of the front of a display piece. (By the way, the refueling station was removed as well, leaving a small but symmetric and painted hole that serves as additional ventilation, and a "sniffer station" - a place to get a whiff of burning electrical components when I need to convince myself that nothing's fried.)

So when I spend enough time staring at the model and decide to play with it, a quick flip of the power switch and I'm in business. The Hitec Flash 5 provides Channel 5 for instant ESC accommodation; a three-position switch allows throttle selections of 0%, 50%, and 100% power. This leaves the original Channel 3 available at this point (and as yet unused).

A close-up view of the electric engine installation reveals additional room for scale engine detail. I haven't messed with it yet because the engine assembly needs to come off for battery replacement, and I've been recycling new ones to break them in. Engine detail would be kinda cool, but needs to be done thoughtfully so that engine removal isn't compromised in the field.

This is a project I'll tackle one rainy day when the inspiration strikes. It'll probably involve radial plastic detailing that detaches prior to engine removal. The shiny point in the lower right portion of the cowling is one of the four screws to be removed when changing batteries. A rotating jeweller's driver makes this operation fairly quick to accomplish.

The overall appearance of a display piece is obviously enhanced unless your audience is a committed engine freak. Nonetheless, when the engine is required for a subsequent project and you don't need the model to hang naked and without dignity, an electric conversion is a great way to fill up space and provide something on which to hang a propeller.

In this instance, the resulting conversion is actually functional. While this version of the airplane doesn't come close to the performance of its fueled alter-ego, it's not a bad price to pay for a version that unarguably performs better than the rubber-powered original upon which this plane is based!

Interested and looking for inspiration? Check out Guillow Models' selection of timeless scale models. There are a number of highly intriguing Guillow projects well-represented on the Web; but this is the only Sopwith Camel that I'm familiar with that has a web-presence... and the only Guillow project to date that I know about that converts readily between electric and fuel.

Reflections The key to an acceptably performing electric conversion, especially a scale Guillow, lies in building the lightest airframe possible. Clearly we don't do this when building a beefed up fiberglassed airframe for an overpowered engine application. So if there was ever a set of conflicting design goals, this page certainly encompasses a couple. The alternative of course, is to go into electric with a beefed up motor and battery combination, eg., an Aveox 1015/2Y brushless (or Astro equivalent) and the concommitant battery support. The problem therein lies in the amount of weight (not to mention the expense!) required to support the combination. It just seems easier to put a fuel engine up front and spend the extra couple hundred dollars saved on another project.

But "conflicting design goals" is my bread-and-butter. And I just know I'll be laying in bed getting gnawed at by the associated challenges and the soldering iron in the other room just beckons me, calling my name gently, whispering, "Billy..., Billy..."