Lavochkin LA7

  • This review was first published in RCM&E July 2003. The kit is still available (see datafile). 

The lineage of the LA7, one of W.W.II’s most effective medium-altitude fighters, extends back through a series of aircraft built by LaGG, the experimental aircraft bureau established by Semyon Lavochkin, Vladimir Gorbunov and Mikhail Gudkow. From the outset, what set LaGG apart from other Soviet manufacturers was its use of wood in the construction of airframes. While most domestic and foreign firms were designing aircraft that relied on metal construction, LaGG was anticipating the effects upon aircraft production of raw material shortages in wartime: “Even if only one small grove of trees is left in Russia,” Gorbunov said, “we shall still be able to build fighters.” The LaGG approach offered other advantages: the birch tar-impregnated wood was not only stronger, but fire-retardant, too, and skinning aircraft with birch veneer and ply makes for a smooth finish and that doesn’t distort in the way that aluminium does.

Working in a former furniture factory, LaGG set about building a prototype - a single-seat low-wing monoplane dubbed the I-301 - that eventually evolved into the LaGG 3. Despite its robustness and effectiveness in the ground-attack role, the LaGG 3 was unpopular with crews, and performed poorly when compared to the Yak 1 and Yak 7 (which used the same 1000 hp Klimov M105 engine), and more importantly when pitted against the Bf 109. Heavy, crude, and dogged by poor quality-control, it was nicknamed the ‘varnished coffin’ by many of its pilots.

To improve performance, the Klimov engine was replaced first with the 1400bhp M107 motor, and then with Shvetsov’s 1700hp ASh-82A radial engine. While the close-cowled radial suffered cooling problems, it also increased the airframe’s straight-line speed by 10 per cent, and could out-perform all other combat aircraft on the Eastern Front in the climb to 3600ft. Against this were set high stick forces and a slow turning circle, but the aircraft was nonetheless proving very popular with units at the front, where its relative crudeness made it easy to service in the field.

Although Lavochkin originally considered the La5 something of a stop-gap measure, between June ‘42 and March ‘44 thousands were built, and the design underwent continual development to reduce weight and drag (including persuading pilots to fly with the canopy closed and tail wheel retracted, apparently!). The final iteration, the La5FN, segued into the 660kph La-7, which entered service in the summer of ‘44 when a batch of 20 was sent for trials with the 63rd Guards Air Fighter Corps. During the course of the ‘trials’, the La7s flew 462 combat sorties and shot down 55 enemy aircraft for just four combat losses. The type quickly proved itself the dominant aircraft on the Eastern Front, out-performing even the FW190 A8 variant in terms of climb, speed and manoeuvrability.

By the end of hostilities, over 5000 La7s had been produced, and the aircraft remained in service with the Soviets until ‘47. Ironically, given their combat survivability, only two La7s are left, one in the Prague Kbely museum the other - Kozhedub’s White 27 - at Moscow’s Monino air museum.

GET STUCK IN
We’re in familiar Warbirds building territory with this kit: you get a box packed with parts (foam wing cores and decks, pre-cut ply and balsa components, and plastic mouldings for the canopy, cowling and gun blisters) and such is the level of pre-construction, there’s very little work between you and your first sortie.

Beyond fitting the leading edges and the wing-tip blocks to the veneered foam wing-panels, for example, you only need to transfer the aileron positions from the plans and cut out the control surfaces using a fine-toothed saw. The edges of the aileron and wing cut-outs are then trimmed back so that 1/4” facings can be glued in place.

Once you’ve hinged the ailerons, the control rods are laid into the pre-cut channels, which are then covered with 1/8” ply strip. All one has to do then is sand the dihedral onto the wing roots, join the panels with epoxy and cut out the servo bay (or bays, if you’re fitting retracts). Finally, the wing-panel join is reinforced with a fibreglass bandage in the usual way.

THE RETRACT OPTION
Although a fixed undercarriage is supplied, most modellers will probably want to add Warbirds’ retract pack. Using the overlay supplied, the wheel wells are marked and cut out using a scalpel. A hot wire is ideal for removing the core foam from the wells, which can be lined with 1/8” ply before the ply mounting plates are glued in place. Finally, the wheel-well liners are fitted, and holes cut between the wells and the servo bay for the pushrods. When wiring-up the retracts, don’t forget to fit an in-line fuse to protect the receiver supply.

COWLING
Although you’ll be keen to get on with the fuselage, it’s worth assembling the cowling first. The mouldings supplied in three parts, and it’s handy to use formers F1 and F2 to support the pieces while you glue and tape them together. Speaking of glue, I used the solvent sold by plumbers merchants for gluing polypipe and, once it had set, the joints were reinforced by laying glassfibre tissue and resin around the inside of the cowling.

You’ll see that I was able to keep the cowling lines clean by doing away with the mixture needle. Mixture control for the model’s SC .52 four-stroke engine is now managed by a servo mounted behind F2. This means that fuel metering can be adjusted in-flight, and it’s such a neat and simple alternative to untidy needles, I’m surprised more people don’t do it.

FUSELAGE
In common with other kits in the range the fuselage is a simple box construction using balsa sides and ply doublers. These are attached to three formers and a tail post which, in turn, are fitted to a central crutch. The three formers slot onto the crutch and require only their positions to be marked from the plan before fitting. With these square you’re almost guaranteed a straight fuselage.

Don’t forget that you should drill all the necessary holes in F1 for fuel feed pipes and what have you, and fit the engine mount before you glue the bulkhead in place.

The upper fuselage is formed by two foam decks with 1/8 sheet cockpit sides and two 1/4” sheet tailplane seats glued to the crutch behind the rear deck.

TAIL FEATHERS
Tail surfaces are made from 1/4” soft balsa sheet, though you may wish to start by sanding the tail / fin fairing to match the cross-sectional contours of the fuselage. In order to avoid accidentally sanding grooves in the tailplane during the profiling operation, you can make life easy by temporarily replacing the stabilizer with scrap 1/4” sheet, tack glued in position. Profile and fair the tail end / fin to your heart’s content then, when you’ve finished, you can simply remove the substitute surface and replace with the proper item.

All that remains then is to sheet the underside of the fuselage with the 1/8” balsa provided. Actually, you may be interested to know, while you’re plying the PVA, that the phenolic adhesive used by LaGG on the full-size La7 could bridge cutting and finishing errors of as much as 3mm in the aircraft’s wooden components. Happily, Warbirds’ CNC machine-cut parts mean you won’t have the same quality control issues!

FINAL ASSEMBLY & FINISHING
Elevator, rudder and throttle servos are fitted side-by-side on a rail in the bay behind the fuel tank, whilst the aileron and retract dittos are housed in the wing, as mentioned earlier.

Prior to fitting the canopy you may want to embellish the cockpit area with the Warbirds pilot and instrument panel, just to add that finishing touch. In truth, the LA7 instrumentation was notoriously basic, extending to little more than a compass, asi, vsi, rev’ counter, temperature gauges for oil and engine, and a clock. Anyway, this done, the model was covered with brown parcel paper, the ABS gun breech mouldings added, and the whole kit ‘n’ caboodle was sealed with a coat of dope.

Impressive as the Warbirds decal pack is, I rather enjoy painting the insignia on my models as it means I can individualise them. The colour scheme that I chose in this instance is that of White 27, which was flown by Ivan Kozhedub, the Soviet Union’s highest scoring fighter pilot during W.W.II. Apart from Kozhedub’s success against the Germans - he’s credited with 62 kills, and was the only Soviet to shoot down a Messerschmitt 262 - White 27 was one of the few La7s to have the star insignia on top of the wings.

The main colour scheme was applied using Humbrol enamels and an airbrush (use aerosols if you don’t have an airbrush). As for the insignia? These were marked out lightly with a pencil, outlined with a ruling pen, then filled with brushed enamel paint. Panel lines were added with a fibre tip pen, and the rivets highlighted in white before the whole airframe was given two coats of polyurethane satin varnish.
Finally, if scale detail’s important to you, it’s worth spending the time making a three-bladed propeller for display purposes - it doesn’t take long to carve the blades from balsa then glue them to an old spinner, and it really looks the part.

FLYING WHITE 27
Despite its tapered wing, the La7 is just as well-behaved as my Warbirds Bf 109G and Spitfire models. After flying only a few circuits to get the feel of the Lavochkin and trim her out, I felt quite confident to try a few manoeuvres. The La7 seems equally happy flying inverted, needing just a touch of elevator to keep her straight and level. Aileron rolls are easy, and look very realistic when done slowly, while the power of the SC .52 lets you fly big, lazy loops. Having said that, I reckon the model looks at its best when making a low fast pass!

Bringing the Lavochkin back into the circuit, I cut the power and turned into wind. With the engine ticking over, the stability and low stall-speed made it obvious that getting her in wasn’t going to cause any problems: she touched down smoothly, and the landing was easy to keep straight thanks to that wide-track undercart.

SUMMARY
The Lavochkin is an unusual and interesting subject to find in kit form, and Warbirds’ model is definitely one to add to your collection. The kit is a pleasure to build and fly: most of the work has already been done for you, the instructions and full-size plans make short of what’s left, and when you’re through it’s one of the easiest warbirds you’re ever likely to fly.

DATAFILE

Name: Lavochkin LA-7
Model type: Scale W.W.II fighter
Manufacturer: Warbirds Replica Flying Models
17 Curzon Way, Chelmsford,
Essex CM2 6PF. Tel: 01245 284791
RRP: £89.95
Wingspan: 56''
Rec’d engine: .40 - .46 2-stroke / .52 4-stroke
All-up weight: 6 lb 9oz
Wing loading: 26 oz / sq. ft.
Control functions: Rudder, elevator, aileron, throttle, retracts (optional)

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