Grumman F7 F-3 Tigercat
Building instructions - Grumman F7 F-3 Tigercat
2
Power system for 10 cells:
Race 400-6.0 V with 2.33 - 2.64 : 1 gearbox
Order No. 7121/05 or 7121/06
With 21.5 x 15 cm / 8.5 x 6” propellers
Order No. 7228/28 or 7229/28
Propeller adaptor for 4 mm Ø shaft
Order No. 7124/14
Power system for 8 to 10 cells:
Permax 400 BB, Kyosho AP 29BB (“480” class)
With propeller adaptor
Order No. 7120.90
Motor mount “M”
Order No. 7120/94
Gearbox housing
Order No. 7120/98
Gear set, 3.0:1, pinion with 3.17 mm bore
Order No. 7121/79
Ballrace
Order No. 7821/41 and 7822/40
With 21.5 x 15 cm / 8.5 x 6” propeller
Order No. 7228/28 or 7229/28
Propeller adaptor for 4 mm Ø shaft
Order No. 7124/14
The motors must be adjusted (re-timed) for left-hand rotation as described in the gearbox operating
instructions, and some motors must be run-in before use. 480-size motors must not be re-timed by more
than 7 mm, otherwise the rear bearing plate may fall off! The ideal rotational speed for a safe hand-launch
is around 8400 rpm (with a freshly charged battery). The propellers must be balanced as accurately as
possible, but before you do this it is important to check the true-running of the propeller adaptors, and
correct with the socket-head grubscrews if necessary. Check that the blade tips spin in the same plane.
The best way of correcting any discrepancy is by rotating the propeller relative to the propeller adaptor,
working in small increments.
For running-in, and for setting up the motors for synchronous running, we recommend installing the
motors on a “T” mount made of solid wood rails. This is not necessary with brushless motors.
If you are using 480-size motors, we recommend that you adopt the method of motor control which
involves the throttle channel trim. This is described in the “Flying” section, and is applicable for both cell
counts.
Brushless power system
: direct-drive motors
actro C-6, see section N-N
Order No. 7002/36
Motor mount "M"
Order No. 7120/95
Propeller adaptor for 5 mm Ø shaft
Order No. 7124/15
With 21.5 x 15 cm / 8.5 x 6” propeller
Order No. 7228/28 or 7229/28
Recommended battery: 8-10 cells, NMH 300
Order No. 7443/60
Or Sanyo 2000 RC / 2400
Motors with nose bulkhead mounting: see section N-N
Motor mount “M”
Order No. 7120/95
To ensure that the speed control system works reliably with brushless motors, each motor needs its own
controller. Caution: you must not activate two BEC systems! Switch on the BEC on one of the controllers,
and fix the second BEC switch in the OFF position! Naturally the brake must be switched off. The little
trick we describe in the “Flying” section, concerning the use of the throttle channel trim lever, only works if
both controllers are connected using a Y-lead.
Preparations for building:
These building instructions include reduced-scale drawings of the die-cut sheets. Use these drawings to
write the Part No. on each component using a soft pencil, then separate the parts from the die-cut sheets
using a balsa knife. Trial-fit all parts before installation, as many are supplied slightly oversize to allow for
trimming. Formers which are to be glued in the GRP parts must be trimmed very carefully, and should just
make contact with the skin; they will push the mouldings out of shape if they press on the very thin shell.
You can deviate from the sequence described in these building instructions if you so desire, but it is up to
you to think the consequences through!
Keep the building instructions, parts list, motors, servos, receiver and the selected battery to hand at all
times during construction, as they are all useful aids. Micro-servos and a small receiver are basic
essentials with models of this type.
Before starting construction thoroughly rub down the surfaces of all GRP parts with 400 abrasive paper,
used wet.
