Sharkit 1/72 Edgley EA-7 Optica: Part 1

Sharkit Optica box art

This is a resin-and-vacuform kit of the extraordinary Edgley Optica, an aircraft I’ve wanted to model for a while. The Sharkit kit is the only one currently available, though there has been a cycle of rumour and hint from other manufacturers for a while. It’s pretty basic, to the point of being sparse. Below, you see everything that comes in the box, with the exception of the instruction sheet:

Sharkit Optica parts
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There are two vacuform cockpit canopies, but one of mine has a nasty fold in it, which limits my scope for error while fitting the canopy over the cockpit. The cockpit itself is depicted by three seats and an instrument panel—no control columns or rudder pedals. The fan nacelle has five pour stubs awkwardly positioned inside it, but the resin is soft enough to allow these to be clipped out with a side-cutter. Apart from that, the resin seemed to be in fairly good condition, with only a little filling and sanding required.

The resin frame of the cockpit canopy did need a bit of work. Firstly, I used some styrene strip to add an overhead central bar. This was an internal structure, but it’s not clear to me why it isn’t moulded into the kit resin. Instead, the kit instructions simply point out where it should go and tell you to add it yourself.

Secondly, the frame provided in my kit had a nasty skew to it:

Sharkit Optica distorted canopy frame
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It looked as if the canopy strut at the left had been stretched and thinned at some point. I clipped a millimetre out of it, sanded down an awkward knee, and filled out the thinned part with epoxy. With this done, it popped fairly neatly into the vacuform canopy:

Sharkit Optica added canopy fit
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Sharkit Optica added canopy bar
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You can see the additional bar I added.

Then I assembled the wings, nacelle and tail booms, and dry-fitted the cockpit floor and engine. I had a strong suspicion this one would want to sit on its tail, so I taped a cocktail stick rocker along the line of the main undercarriage:

Sharkit Optica undercarriage rocker test
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Then I balanced the thing on the rocker, and tested to see how much lead I’d need to load into the cockpit to get the model to rock forward on to its nose wheel:

Sharkit Optica check balance
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With the cockpit furniture roughly in position, I added lead shot. It turns out it needs much more weight than I would be able to conceal in the Optica’s very open cockpit, with a thin base and a canopy that extends all the way to the floor.

So it wasn’t going to sit on its undercarriage without some sort of support at the rear. This actually wouldn’t have been a problem if I intended building the yellow prototype G-BGMW that the kit is intended to depict. This had a little fold-down stabilizing leg under the nacelle, which you can see here:

Edgley EA-7 Optica by Steve Fitzgerald
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Photograph copyright Steve Fitzgerald, used under GNU Free Documentation Licence 1.2 from this source

The kit models this in the stowed position, as a rather amorphous lump on the underside of the fan nacelle, but it could easily be modified to depict a parked version of the aircraft.

Unfortunately, I’m planning to build a later design, which lacked the parking support—presumably later models had a centre of gravity that sat farther forward than the prototypes.

Plan B, then, was to go for an in-flight depiction. With a fixed undercarriage and the fan concealed inside the nacelle, there would be no problem with portraying the aircraft in flight, if I could install a pilot. I started knocking one together, using two pilot figures from PJ Production—the body of a First World War aviator, and the head of a transport pilot, with a little polythene to give him a longer coat.

Modified PJ Products 1/72 pilot
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The reason for this eccentric mixture comes from the particular aircraft I want to build:

Slipstream Optica 1
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Some Optica enthusiasts will recognize it immediately, but more on that in due course.

I drilled out locating holes for the undercarriage, and then went on to modify the fuselage and wings to depict my aircraft of choice. I removed the lump from the underside of the nacelle, added a couple of shrouds around the undercarriage roots, extended the elevator trim tab and the back of the nacelle, and placed a couple of wing fences on the upper wings. There are other details (flap control levers, pitot tube, etc) that will come later.

Sharkit Optica mods, top view
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Sharkit Optica mods, bottom view
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I also rescribed the panel lines, which were rather faintly moulded. Some needed to be added to the area where I had removed resin from the underside of the nacelle.

The main undercarriage acquired some brake lines fashioned from stretched sprue, and the nose wheel a little stone-guard made out of epoxy and styrene strip.

The fuselage then got a coat of primer, and was marked up in the basic livery of my aircraft. I used a little LifeColor Liquid Pigment to darken the panel lines.

Sharkit Optica basic paint 1
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Sharkit Optica basic paint 2
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The cockpit was detailed with control columns and rudder pedals made from brass rod. I added the instrument panel between the seats, widened the kit’s instrument panel to match the larger unit in my chosen aircraft, and installed an overhead control box (visible in the photograph of the real aircraft, above). The pilot meanwhile acquired his wet-look drape coat and raised collar.

Sharkit Optica cockpit and PJ productions modified pilot
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And it was at this point I found that the 1/72 scale pilot didn’t fit the 1/72 cockpit. Even after carving a chunk of his buttocks away, to simulate the natural compression of seat cushions, his head would have been pressed against the cockpit roof. Sigh.

Plan C therefore involves coming up with a way to display this thing standing on its undercarriage, despite the kit’s desire to fall over backwards. I’ll let you know how that goes.

So I added the canopy frame to an empty cockpit. Before adding the vacuform bubble over the top of everything, I used the assembled canopy frame as a template for some paint masks, to be supplemented with liquid masking agent to deal with the two-plane curvature of the canopy bubble:

Sharkit Optica cockpit and paint masks
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(The kit instructions suggest just leaving the vacuform bubble shiny and pristine over the painted canopy frame, but that seems like a very ugly and unconvincing approach.)

Then the canopy went on—a process that involved trimming the rear of the bubble very carefully to butt against the nacelle supports behind the cockpit, and then carving a smooth lower edge to suggest the bottom of the cockpit doors. The fit was bad at the “chin” of the aircraft—the moulded canopy had a couple of creases that forced me to trim it alarmingly close to the edge of the cockpit floor, and it also had the wrong curvature, sitting with a gap between vacuform and resin. I eventually solved this by slitting and overlapping the vacuform at the point where the real aircraft mounted a pair of landing lights. That let me tightening the vacuform into a snug fit, with a seam that I could conceal later.

Sharkit Optica canopy in place, masks ready 1
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Sharkit Optica canopy in place, masks ready 2
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It all looks nice and smooth and shiny, but you can see how it really needs some surface paint to give the appearance of real canopy struts and doors. Before masking, I added a little stub antenna to the roof, a couple of blobs of cyanoacrylate to simulate the cockpit door hinges, and a pair of landing lights which also served to obscure the seam I’d carved in the vacuform.

When my hand-carved masks went on, they needed to be supplemented a little—because the vacuform stands out a little from the frame I’d used as a template, the masked area needed to be extended around the lower part of the canopy.

Sharkit Optica paint mask
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But they did the job. A very little tidying of edges using a cocktail stick to gently lift paint runs, and the cockpit is complete.

Sharkit Optica painted cockpit 3
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Sharkit Optica painted cockpit 2
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Sharkit Optica painted cockpit 1
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The landing lights should really be recessed flush with the canopy, but I didn’t want to risk damage to an already precariously botched-together area, so I left them standing proud. In the lowermost photograph, you can pick out another little bit of scratch building I added before closing the canopy. The real aircraft had a mesh “cargo net” just behind the seats—I modelled this with a scrap of polythene and some stretched sprue.

Next time—home-made decals and more detailing.

4 thoughts on “Sharkit 1/72 Edgley EA-7 Optica: Part 1”

  1. Wow, a previously unknown aircraft for me.

    Is it just me or does anyone else find the design has the intake too close to the ground?

    It looks as though rough field taxiing would hoover up all sorts of FOD, from gophers to cow flops. But from the pictures of the actual aircraft I guess that isn’t so.

    So I’m going to surmise its turbofan engine isn’t on par, power wise, with the S-3 Viking’s turbofans.

    And another problematic design feature I see is that technically it’s a “pusher” plane. So you have the problem of rough landings being less survivable than other aircraft designs. (Stop too quickly or too roughly and the engine comes forward to visit you in the cockpit. An undesirable outcome, to be sure.) Even at automobile accident speeds.

    But I guess as a flying tour bus it’s a perfectly adequate design.

    And after all that I just know you’re mention something marvelous and innovative about it. 🙂

    1. There’s no turbo- to that fan–it’s a just a ducted fan driven by a six-cylinder Lycoming, which sits in the fairing that protrudes behind the nacelle.
      Landing speed is about 55kts with full flaps–the aircraft was designed to have a slow loiter speed, making it an alternative to a helicopter for observation duties. And it’s so light that a counterweight needs to be moved back and forth along the length of the aircraft according to the number of passengers.
      It can reportedly ingest stones during taxiing and take-off–there’s a protective net that can be fitted across the lower half of the nacelle for rough field duties.
      You can read a lot more detail in a flight test report here: http://www.tetsui.net/files/optica_flight_test1.pdf

  2. Oh Lord, where did my manners go?

    Sorry Doc. Too much isolation, (since March!), and I’m forgetting how to speak in polite society.

    All those paragraphs dealing with the faults in the model and how you cleverly overcame them and I go nattering on about perceived faults in the actual aircraft, with no mention of the above. That was a little more braindead than usual of me.

    Yeoman work as usual, sir.

    I know of only one person who matches your skills with modeling. He’s a retired integrated circuit designer I spoke of before who made most of the German and Soviet WWII armor, including stuff that didn’t have kits, he just knew what they derived from and would use those kits and make the changes.

    (Lastly, as far as the anti-FOD safety net idea, if you had your druthers, would you rather the engine ingested a rock on take off…or the net?)

    1. No worries, Don. These build logs are as much about the aircraft as about the kits.
      With reference to the fan and FOD, it’s interesting how a couple of flight test reports simply describe slowing down when taxiing over loose stones. So it seems to be considered an issue, but not a major issue.
      On the issue of the net, I guess I’d need to look at how well the net was fixed…

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