FMA—HydroHawk ARF Spotlight

Please read this entire on-line manual supplement first before starting the assembly of your FMA HydroHawk ARF.

We have found several improvements for the positioning of components like the battery pack and motor.

Cutting the foam canopy for the improved battery placement is easiest done before gluing it to the deck.

Note that the HydroHawk is for intermediate to advanced flyers only!


In the Box:

NOTE: Click on any of the accompanying photos for larger view.

Box Top with Decals & Manual
ARF Parts Grouped & Wrapped
Pre-Installed Floats & Runners

Parts from the Box:

Top of Boat
Brushless Power System
Bottom of Boat
Pre-made Control Surfaces
Top Elevator and Stab
Decals
Manual and Foam Canopy

 

The power system was tested using two different size Cellpro Kokam packs. The packs measured as follows with the stock GWS 8x4.3 prop.

  • 3.0oz, 3-cell, Cellpro Kokam 910mAh pack, 13.5amps, 130w
  • 4.2oz, 3-cell, Cellpro Kokam 1250mAh pack, 15amps, 150w

Assembly:

The slot in the foam canopy may need to be cut longer as shown above.

Note:

The canopy slot may need to
be lengthened as shown to move the motor mount and battery forward to obtain the proper CG of 3.0".

This longer slot may already
be cut on your version.

The foam slot shown above is cut for proper CG of 3.0"

 

Position and insert elevators, glue with thin CA on each side
Cut away covering using a sharp razor knife
Glue foam canopy to body using 5-minute epoxy

Position the lower elevators using the supplied hinges and then secure in place with several drops of thin CA on both sides

to soak the fiber hinge material. Epoxy the foam canopy onto the main body. Before doing so, you may want to

test fit the motor mount assembly and cut away a thin amount of inner foam, if needed.

 

Epoxy the 3 Vertical Stabs
Attach rudder hinges using thin CA
Epoxy top stabilizer in 3 places
Epoxy the top stabilier in 3 places

Epoxy the vertical stabilizers in place making sure that they are at right angles to the main body.

Attach the rudder using the supplied hinges and soak with thin CA.

 

Test fit the motor mount and cut away inner foam wall, if needed
Attach the motor mount using either white glue or epoxy
Secure the motor as shown on the stick with the two supplied screws

NOTE: The balsa motor mount assembly may not fit flush with the bottom of the main deck. You should have a slight up-thrust and right-thrust in the prop angle when finished. This is easily detected by temporarily pushing the brushless motor onto the stick mount and viewing the prop. Position the prop for slight upthrust and right thrust while the epoxy dries.

The motor mount can be glued with either white glue or epoxy. The inner foam wall of the canopy may need to be

widened with a razor knife before the motor mount fits.

Press the motor in place on the stick and secure with the two supplied screws.

Note that the motor assembly must be positioned above the stick for improved flying performance

and prop ground clearance.

 

Linkages:

Note that the left and right pairs of elevators require an elevon mix either at the receiver using a tiny external device

or at the transmitter if it has an elevon mix feature. The mix allows the four elevator control surfaces to act as both

elevators and ailerons; called elevons. The elevon mix is required to fly this model properly.

If your transmitter does not have a mixing fucntion, use the FMA MX80 Elevon Mixer

 

When viewed from the rear of the model, all 4 surfaces go up for up elevator (down stick).

For right aileron stick, both right surfaces on the top and bottom decks go up and the left two surfaces go down.

This is reversed for left aileron stick.

We started with the throws set to +- 10 to 15 degrees on the elevons and full swing on the rudder. Use 50% exponential on the elevons, if your transmitter supports this function.

 

Mount the rudder linkage and servo
Mount the right elevon linkage and servo
Position M5 receiver, switch, motor, and ESC as shown
Connect top deck to bottom
Top deck linkage uses "Z" bend
Apply decals as shown

 

The M5v2 receiver fits nicely in the rear of the foam canopy

The servos were mounted to a small piece of balsa using servo tape and then the balsa was CA'ed to the body.

The M5 v2 receiver fits nicely in the rear of the canopy with the antenna wire routed through the rudder servo opening.

The three brushless motor wires are secured to the motor post which holds the ESC in place from the rear.

The ESC is held from the frontby the power connector into the body of the boat.

The top deck linkage uses the "Z" bend end of the metal rod after first removing the quick link.

The ESC ends were sealed with P.F.M. silicone paste (from Hobby Lobby) to prevent water getting in. Use a plumber's Goop or silicone paste that dries flexible. Be certain to seal both ends as ESCs do not like water!

 

 

Finishing the HydroHawk:

 

The Cellpro 3-cell 910mAh battery pack slides into position

Final Steps

The battery position shown on the left works fine and is easiest to build.

The battery position shown on the right improves flight performance as the weight is closer to balanced on both top and bottom sides. It also allows the canopy top to be sealed to protect the receiver from water splash.

Note new battery and motor positions for improved flying performance.

 

FMA HydroHawk

Ready-To-Fly

The components fit very well and the proper CG of 3.0" back from the start of the main deck was right at the step in the floats.

The FMA HydroHawk ARF was ready to fly at 15oz with the 3oz Cellpro Kokam 910mAh pack.

FMA HydroHawk

Setting the CG

Note: If the CG cannot be obtained at 3" (or slightly less) back from the start of the main deck, add 1/4oz lead weights to the tips of the foam floats until the boat just starts to rock forward with the battery installed.

The weights can be glued in flush with the inside surface of each float near the tip and covered or painted red.

 

 

Test Flying:

Note that the HydroHawk is for intermediate to advanced flyers only!

HydroHawk

Video 1 (4.5meg)

The first video was taken during 10mph winds. The HydroHawk needed to keep the speed up so the wind wouldn't push it around.

HydroHawk
HydroHawk

Video 2 (6.7meg)

The second video was taken in calmer conditions with about 5mph winds. It was easier to slow fly the HydroHawk and we had a blast taking off the grass and performing loops and rolls.

HydroHawk
HydroHawk

Video 3 (4.2meg)

This is a temporary video showing the HydroHawk on water take-offs in 15mph winds and a shaky camera guy. We'll replace it soon but you get the idea.

HydroHawk

 

 

HydroHawk Rocks!

We are very happy with the performance of the FMA HydroHawk. It flies great and is very rugged. Another great value from FMA Direct!








SHOPPING CART | HOME | SPECIALS | JOIN EMAIL

FMA Direct • 5713 Industry Lane, Suite 50 • Frederick, MD 21704
800.343.2934 • Fax: 301.668.7619 • Tech/Service: 301.668.4280
Home Shopping Cart Shopping Cart Specials E-mail E-mail