.
Tank Installation
NOTE: Engines such as the Cox Black Widow have the tank built as an integral part of the engine. If an engine such as
this is used there is no need for a plastic clunk type fuel tank.
The Hummer's engine is not fully enclosed so only one vent line is needed in the fuel tank. With a single vent set-up, fill the
tank by disconnecting the fuel feed tube from the carburetor and pumping fuel into the tank through it. When fuel runs out
the vent tube, the tank is full.
A 1 or 2 ounce plastic clunk-type fuel tank (such as the Sullivan 5S-1 or SS-2) fits best in the Hummer. The tank is
mounted by drilling two small holes to allow the brass tubing to stick through the firewall. The fuel tubing is then slipped
over the brass tubing outside the fuselage. Stuff foam rubber under and around the tank to keep it in position.
Radio Installation
It is best to follow the manufacturer's
recommendations when installing your
radio. Most radio's come with some type
of plastic tray such a these two Futaba
servo trays (shown below). The type H
tray works well for the elevator servo,
and the type V is used for the aileron
servo.
If plastic trays are not available, you may use hardwood rails to mount the servos. Using a #2 wood screw and a washer,
tighten the screws down against the grommets until the washer is just resting against the grommet without compressing it.
Do not overtighten as the vibration of the model will be transferred to the servo.
The receiver battery pack should be wrapped in foam rubber sheet, held on with rubber bands and placed as far forward
as possible, under the tank. It is a good idea to put the package in a small plastic bag, taped shut around the battery cable
to protect the battery from accidental fuel leakage. The receiver should be similarly wrapped in foam to protect it from
engine vibrations. Cover it with a plastic bag also. The switch may be mounted wherever convenient on the side of the
model. The elevator and ailerons should move 3/16" up and down.
Pre-Flight
Be certain to carefully range check your radio equipment and see how it operates with the engine running before
attempting test flights. A lot of problems can be avoided if the engine has been well broken-in and the needle valve
adjustment perfected on a test block or in another airplane before installation in the model.
The Balance Point position is shown on the side view drawing of the plans. Do not balance any further back than this point
even if lead must be added to the nose. Trying to fly with the Balance Point too far back is much more dangerous than the
slight increase in wing loading caused by adding . nose weight. Balance with an empty fuel tank. When slightly nose heavy
the model will be a great deal more stable and less likely to stall or snap roll. The reaction to control movements is also
less sensitive with a forward Balance Point so it is not so easy to overcontrol. Some aerobatic ability may be sacrificed with
a forward Balance Point so you may wish after test and familiarizations flights, to adjust the balance slightly to suit your
own preferences and conditions. Do this gradually and check results and control response in the air. In case all of this talk
makes you somewhat uncertain, rest assured that the Balance Point shown in the side view has been thoroughly proven
by test flying several prototype models.
A properly balanced and aligned model with a reliable engine and radio is more assured of successful flights.
Flying
As mentioned in the opening paragraph of these instructions, the Hummer is not intended for use as an R/C trainer. If you
are a newcomer to RC model flying, we strongly recommend that you not attempt flying without the assistance of an
experienced RC flyer. Contact your local model club or ask your hobby dealer for the names of good flyers in your area
and a suitable location for flying. Many hours of work are involved in the construction of a model and it can all be lost in a
moment of beginner's indecision. A skilled flier can help you get past the first critical test flights without damaging the
model and give needed instruction in proper control.
Page 13 of 14
Sig Hummer SIGRC50 Instruction Manual