AquaCraft Miss Vegas User Manual

Page 8

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4. Slowly advance the throttle and note if the boat has a

tendency to turn right or left. Adjust the steering trim knob on
your transmitter until the boat runs in a straight line when the
steering wheel is at neutral.

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5. When finished running, stop the engine and turn the

power “OFF” to your boat and transmitter (in that order).

Here are some of the important factors that affect the
performance of a hydroplane.

PROPELLERS

The FRP (Fiber-Reinforced Plastic) prop that comes with your
U-18 Miss Vegas Hydroplane is about the best overall prop for
daily running. If your prop has a ding or chip in a blade you
need to replace it with a new one before you run the boat again.

If you want to step it up and try your hand at even more
performance try a metal prop. Octura makes a Y535
beryllium copper that will work very well on your U-18 Miss
Vegas Hydroplane. Please heed any warning labels that come
with the prop. Take your time sharpening and balancing the
prop using a good prop balancer and lots of elbow grease.
Please do not run any metal prop without first sharpening and
balancing it. Failure to do so will not only slow the boat down
but possibly break driveline parts. Also note that the metal
props can place more load on your engine and driveline;
possibly shortening the life of your hardware.

If you like, Octura offers other props with 3mm [.125"] bore
sizing but caution must be taken that you do not use one that
is to small or to large for the power of your engine. If these
are not available at your local hobby shop, you can contact
Octura Models directly at: (847) 674-7351. Stick with a prop
that is around 35mm [1-3/8"] in diameter. Also keep a look
out for high performance props available soon from
AquaCraft/GrimRacer

™

PROPELLER DEPTH

The depth of the prop is a key factor in establishing the ride
attitude of a hydroplane. Lowering the prop depth will raise the
back of the boat, resulting in a “bow down” ride attitude. A “bow
down” ride increases the amount of sponson whetted surface
pinning the boat on the water and reducing top end speed.

Raising the prop depth will lower the back of the boat, creating a
“bow up” ride attitude. A “bow up” condition may increase speed
but will decrease stability. This may cause the boat to “blow over”
(backward flip) or “spin out” in a turn. See Diagram 1.

PROPELLER ANGLE

This refers to the angle of the prop shaft in relation to the
bottom of the hull. When cutting through the water, the prop
produces both thrust and lift. Thrust generates forward
movement while lift causes the back of the boat to rise
upward. Prop thrust and lift are affected by shape, angle, and
size of the prop blades.

Prop angle adjustment is controlled by moving the strut
forward or back in the strut mounting bracket. Pushing the strut
forward creates “negative” prop angle and will increase the
amount of lift because it increases the prop depth. Pulling the
strut blade back in the mounting bracket creates “positive”
prop angle. This decreases depth and lift. A “neutral” prop
angle reduces the effect of prop lift. See Diagram 2.

ADJUSTING DEPTH AND ANGLE OF THE PROPELLER

Adjustment of prop depth and angle is accomplished by
loosening the 4 x 10mm cap head screw on the strut bracket.
Draw a line on the strut blade with a waterproof marker where
it meets the strut bracket. This will provide a reference point
when making adjustments. It is important to loosen the flexible
drive cable from the engine coupler to prevent creating a bind
in the driveshaft at the rear of the strut housing.

Like any high performance car, airplane, or boat, optimal
outcomes in cornering and speed require “fine tuning” the
variables listed above.

TRIM ADJUSTMENTS FOR THE

U-18 MISS VEGAS HYDROPLANE

Diagram 2

Diagram 1