we used the D8 with a large capacity U-blade and
ice. To alleviate this situation, we built and
skids to tumble the snow windrows produced by
equipped the blade with skids or feet that were
the grader, thus preparing the snow for removal.
sized to easily penetrate the snow to the ice sur-
A huge mound of snow would build up in the
face, but with enough bearing surface to avoid
blade and would ride up the curvature of the
damaging the ice (Fig. 29). Using the skids, it was
blade as the tractor moved forward at good speed.
easy for the bulldozer operator to find and grade
Upon reaching the top edge of the blade, the snow
along the snow/ice interface at significant speed.
would smoothly roll forward in front of the blade
We also attempted to use an angle bulldozer
to be re-ingested a few moments later. This re-
blade, but the tractor was always being pushed
peated tumbling action broke up the hard, lay-
sideways. With the limited traction available on
ered snow and mixed it into a homogeneous, loose
ice, it was very difficult to produce straight wind-
mass of snow that would eventually pour out the
rows. We also experienced the problem of finding
sides of the blade, leaving two windrows.
and maintaining grade, but the skids were diffi-
To remove the snow from the runway area, we
cult to adapt to the angle blade.
used an Oshkosh prime mover equipped with a
One other option was to work the snow with a
Rolba snowblower (Fig. 31). The 2.6-m (8.5-ft)-
multitooth ripper mounted on the back of a Cat-
erpillar D6 tractor. Initially, we had a problem
wide, two-stage blower with a 1.5-m (4.8-ft)-diam.
with loosening the snow without gouging the ice,
ribbon-style drum was mechanically driven (drive
but the outside ripper teeth with "shoes" equipped
shaft). Separate motors powered the blower (300
kW or 400 hp) and the prime mover. The unit we
proved to be very effective (Fig. 30). Subsequent
used had four-wheel drive and four-wheel steer-
addition of a float valve on the ripper hydraulic
controls vastly improved performance and con-
ing, the latter being unnecessary for our applica-
tion. The blower was rated for 2720 tonnes/hr
trol. Passage of the ripper broke free most of the
(3000 tons/hr) with a casting distance of 46 m
snow and left it in small, somewhat tumbled,
(150 ft). The blower head was controllable for up
slabs.
and down (including down pressure), tilt forward
Ultimately, we found that the stock grader
and back, and casting direction (roughly 140 cen-
blade was most effective at peeling the snow free
tered about the vertical with infinitely adjustable
from the natural ice surface. Following the grader,
Figure 28. Initial snow stripping on the Pegasus runway using a bulldozer with U-blade.
31
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