Structural Design

Written by David Algie. Posted in ACA3

The ACA assembles much like a plastic kitset 1:48 scale model does; every part interlocks and self- aligns with it's mating part. All juncture joints are fully filleted and there are no fillet cover panels as each part (i.e. horizontal stabilizer to vertical stabilizer) has half of the fillet built in. All fuselage joints such as upper to lower halves join with a knuckle type joint rather than a lap for true alignment.

The cockpit is a two-piece moulding including the front and rear bulkheads. This with large radiused corners makes an excellent pressurized cell.

The nose of the craft forms a crushable structure in the unlikely event of an impact and with the roll-over protection, the cockpit remains intact.

The elliptical planform wing houses four lightweight fuel bladders rather than a wet type design for improved fire prevention. The wing has no ribs and instead uses nomex honeycomb in it's skins for structural support. The main and secondary spars are an integral part of the skin and bond at the horizontal joint in the middle, as are the horizontal and vertical stabilizer spars. Thus the skin becomes a true sparcap utilizing uni-directional carbon for ultimate strength and light weight. The main and secondary spar carry- throughs in the cockpit are not simple holes cut into the fuselage and glassed over but molded in so the spars and wing fits up from underneath. This also ensures that the cockpit is sealed and stops the fuse from trying to expand with it's internal pressure.

The cockpit door is also integrally laid up with an internal flange for a blow out seal type to withstand the 10 psi differential pressure on it at FL290.

The hydraulically damped main landing gear fastens to the back of the secondary spar inside the fuselage and pnuematically retracts into the aft of the cabin. The hydraulically damped nose wheel retracts up into the front bulkhead, and is mounted by billet aluminum trunnions attached to the main engine frame.

Engine is removable while still on the landing gear. Access panels and wheel well covers are not just cut-outs but laid up integrally yet still 90% detached separate parts. 90% of service access is through the engine cowl and bellypan removal.

Control surfaces are all ball bearing hinged and fully servicable. The aft fuselage and wings are removable in about 90 mins. The dash is a modular design and slides out like a drawer for bench test and service. I could ramble on for quite a while about details but a couple of important points must be evident by now. First, this is a well engineered design with all of the details built into a complete package that becomes an enjoyable kit to construct. Second, it really performs while still having great low speed manners and all at a reasonable price for the immense technology that goes into it!

Some major specifications:

Wingspan 27'
Length 21'
Height 7'
Tailspan 10'
Wing area 82.5 sq. ft.
Wing loading 23 lbs/sq. ft.
Fuel capacity 62 gal.(82 with underwing LR tanks)
Cockpit width 42" Inside
Baggage cubic area 7.25 Cu. Ft., 38" wide, 22" deep, 15" high
Empty Weight 1080 lbs.
Cruise speed 385 MPH.
Payload 822 lbs.
Engine Type GM Corvette LS3/LS7(!) V8
Turbo System Normalised to sea level @ FL290
Cockpit Pressurisation Sea level @ FL290
Engine Cubic Capacity 6.3 Litre (7 Litre for the LS7)
Fuel Burn @ 65%-300 HP 14.5 Gal/ Hour.
Engine Weight, wet with turbo 500 lbs.
Gearbox reduction Ratio, standard 1.385:1 (Can go up to 2.75:1)