|
CARISI - PRODUCT DESIGN | | PAGE 1 of 3 |
| PREPARED Vincent Carisi | 8/21/54 | REPORT NO.
CB-1 |
| CHECKED | | MODEL CBY-3 |
| TITLE: Summary Report - Structural Study - Burnelli
Loadmaster
|
1. Scope of Study
1.1 Study was made on the basis of production drawings and physical inspection of the
aircraft as well as from personal familiarity with the configuration extending over the past 15
years or more.
1.2 This report is a summary of findings which will be exposed in a more detailed manner
in a subsequent final report.
2. General Configuration
2.1 Unlike the "conventional" aircraft, where aerodynamic advancement is usually brought
about at the cost of increased structural complication, this aircraft depends for its performance
on the very principles which simplify its structure.
2.1.1 The lifting body (which replaces the conventional fuselage) is of airfoil
cross-section, generating spanwise in a straight line. Thus both upper and lower surfaces are of
single curvature. Any transverse section is rectangular.
2.1.2 The pilot's nacelle, while embodying compound curvature, is non-structural.
Tail booms are conventional box-beam structures with rounded fairings at top and bottom edges.
2.1.3 Tail booms are conventional box-beam structures with rounded fairings at top and
bottom edges.
2.1.4 Tail surfaces are conventional.
2.1.5 Outer wing panels are of conventional configuration. However, since the body
contributes to the total lift, they are much smaller in area than would be the wing panels of a
conventional airplane of equivalent payload and power. Since the transverse bending moments are
very low compared to those of a dead-weight fuselage aircraft, substantial economies are effected
in structural weight.
2.1.6 Landing gear design is the simplest possible single hinge type. Its installation
is highly simplified by the uncomplicated and extremely rigid nature of the body structure to
which it attaches.
2.1.7 Engine installation utilises standard "package" nacelle units which are very simply
attached to the body structure.
CARISI - PRODUCT DESIGN PAGE 2 of 3
3. Production
3.1 Lofting for parts fabrication and assembly tooling is greatly simplified by the
virtual absence of compound curvatures.
3.1.1 Pre-drilling of attachment and "assembly -pick-up" holes can more accurately be
accomplished in flat layout.
3.1.2 Brackets and attachment fittings for installation of fixed equipment, because of
the regular shapes of the volumes into which they must fit, are simply designed and easily
developed to flat pattern for brake-bending. Location of plumbing and electrical lines is
similarly simplified.
3.1.3 The number of die-line templates necessary is very small, since the need for
hydropress forming is limited to the wing and tail nose-ribs.
3.2 Jigs and fixtures for assembly are fewer and simpler.
3.2.1 A great number of sub-assemblies can be effected without jigs by using the
coordinated-hole method of assembly. (see 3.1.1)
3.2.2 Geodetic points for major assembly fixtures are easily located because of the
regular shape of the envelope. Jig structure is, by the same token, simplified.
3.3 Amount and capacity of capital equipment necessary is smaller than for conventional
configurations.
3.3.1 Since formed parts are limited in number and small in size, hydropresses of large
capacity are not required. (see 3.1.2)
3.3.1.1 Much of the work normally done by hydro-forming can be done on standard
tinsmiths' equipment. (see 3.1.2)
3.3.2 Heat-treating equipment necessary is of comparatively small capacity and low
operation cost.
3.3.3 Large stretch-press for skin forming are unnecessary. The need for stretch forming
is limited to the skins for the lower body corners and the upper and lower tail-boom fairings
(2.1.3). It might be possible, with a small amount of redesign, to eliminate this need
entirely.
CARISI - PRODUCT DESIGN PAGE 3 of 3
3.4 Labor manhours are reduced, and average level of skill required is lower.
3.4.1 Costly straightening after heat-treatment is cut to a minimum.
3.4.2 Trimming after forming is at a minimum.
3.4.3 Components laid-out as in 3.1.1 are easily shear-cut or routed to final dimensions.
3.4.4 Attachment holes can be stack-drilled from simple flat templates on the radial-arm
drill.
3.4.5 Holes in small components can be gang-pierced with standard piercing punch set-ups
in the press-brake.
4. Conclusions
4.1 Lofting this configuration can be accomplished at 1/3 the cost for a conventional
configuration.
4.2 Capital equipment needs are half those necessary for building a conventional airplane.
4.3 Manhour requirements are less than half of requirements for a conventional structure.
4.4 It should be pointed out that the above conclusions are made on a "per pound of
airframe" basis. The CBY-3 has a lower empty weight than any current aircraft of equivalent
capacity.
5. Personal Qualifications
5.1 The above study was made on the basis of 22 years of various experience as aircraft
mechanic, factory superintendent, design engineer, project engineer and design consultant.
Respectfully submitted,
Vincent Carisi
8/22/54 | 
