This land-based
video takes the HydroCar from LAND MODE to WATER MODE by demonstrating the
articulating sponsons. Watch as it literally transforms itself from an
automobile to a tunnel-hulled watercraft.
VIDEO – Water
Test One
When
we first launched the HydroCar, it was pretty obvious that the nose
lacked buoyancy.
Floating
motionless in the water, the craft sat slightly nose down, while the
prop was actually angled up and sticking almost half out of the water.
We
lowered the trim about twelve degrees so the prop could get a better ‘bite’
in the water, but when we brought up the RPM and began to pick up a
little speed, the angle of the prop drove the nose down even farther.
This,
in turn raised the prop nearly halfway out of the water.
As you
can see by the ‘rooster-tail’, it was putting out a lot more power
than it could use – because the prop couldn’t get any ‘bite’ in
the water.
Dropping
the trim even more to give the prop a better ‘bite’ drove the nose
in even farther and made everything worse.
Notice
in the video how the nose is forced farther down into the water as the
speed is increased.
We
were plowing the water in front of us, instead of rising over it…
Plain
and simple – we needed more buoyancy in the nose.
Modifications
after Water Test One:
The
middle and rear underside wings were removed to provide a
less-interrupted water flow to the prop.
The
front wing was replaced with a much larger, upward angled wing for
additional buoyancy.
The
area under the main hull that made clearance for the middle wing was
filled in – also to add some additional buoyancy.
An
auxiliary battery was added to the rear deck for additional cranking
power and weight transfer.
VIDEO
– Water Test Two
With
the added buoyancy in the bow, the HydroCar sat a little bit better, but
was still a little lower at the nose.
The
prop went a little deeper in the water, without lowering the trim as far
– but still not nearly enough.
There
was still way too much ‘rooster-tail’ as the RPM was increased.
It
went a little faster, which showed us that we were on the right track.
Modifications
after Water Test Two:
We
decided to take the front-end buoyancy issue very seriously this time,
so a huge, removable front wing was fabricated and added to the nose. It
is attached at four places, and takes about fifteen minutes to install
or remove.
The
new wing not only added over three hundred pounds of buoyancy to the
nose, but also enhanced shape of the craft’s front end.
About
three hundred pounds of the floatation also foam was removed from the
rear sections of the side sponsons.
This
gave us a total weight transfer of about six hundred pounds...
VIDEO – Water
Test Three
For
the first time, the HydroCar sat in calm water with the nose higher than
the rear.
The
prop only needed to be trimmed down a couple degrees to be completely
submerged.
This
time the front end of the HydroCar actually raised when the RPM was
increased.
The
prop was still creating a huge ‘rooster tail’, so we lowered the
trim to compensate, but still couldn’t get the necessary ‘bite’ to
get it up on plane.
When
adding the trim angle to the angle of the craft, we found the prop was
still angled downward around twelve to fifteen degrees – resulting in
a less than optimal angle for forward motion.
Modifications
after Water Test Three:
We
went back to the dock and added four fifty-pound sandbags to the rear
deck.
We
also switched over to a four-bladed prop with a greater pitch.
We
were hoping that these modifications would result in a better attack
angle for the prop with less cavitation…
VIDEO – Water
Test Four
These
quick modifications resulted in less cavitation and a bit more speed,
but we still couldn’t get it up on plane.
It
almost seemed that the HydroCar had added some weight on the last two
launches – and indeed it had.
At
this point, we thought the main problem was still the prop, not
realizing the rear wheel wells were not self-bailing adequately.
Modifications
after Water Test Four:
Studying
the videos and calculating the latest modifications, it was obvious that
we had gone too far with the weight transfer.
To
understand the problem that we had created, the following is a little
design information:
The
HydroCar’s wheel wells are covered on the bottom with sliding panels
similar to the landing gear doors on an aircraft – but they are not
watertight.
Water
enters the wells through the axle openings as well as around the
bottom panels.
To
drain the water out of the wheel wells, each well is designed with a
trough in the rear to self-bail any water that might accumulate, as
soon as the craft begins to move forward.
The
front wheel wells had adequate-sized troughs, but the rear wheel wells
did not.
On
launches three and four, with a lot of added buoyancy in the nose, the
front wheel wells had self-bailed – but not the rear ones – so
they had actually filled with water.
This
resulted in the craft dragging over six hundred pounds of water along
with it (inside the rear wheel wells.)
Add
to this the removal of three hundred pounds of floatation foam from
the side sponsons, (which was now filled with water) and two hundred
pounds of sandbags – and it was almost like we were dragging an
eleven hundred pound anchor behind us!
So…
The
troughs in the rear wheel wells have been opened up to accommodate the
additional water flow, thus enabling the rear wells to self-bail as
they were originally designed to.
A
keel-cooler was added under the craft to aid in engine cooling while
in WATER MODE.
The
electric / hydraulic marine power steering system was changed over to
an engine driven pump to reduce the current draw on the electrical
system.
The HydroCar is
now ready to go – but the weather in upstate New York is prohibiting any
additional Water Tests until spring.
I’ve recently
had a lot of input from several boating experts and most of them feel we’ve
got it just about everything ‘dialed-in’ except for the prop.
We still need to
find a prop with just the right combination of diameter and pitch, combined with
the proper number of blades, so the HydroCar can optimize its performance.
Once it’s up on
plane, it’s going to be one Hell of a ride!
