Advertisement
CARF-Models P-47
www.carf-models.com
Balance and Flying
The airplane balances at 25% of cord at the wing root. Measure back from the leading edge 15.5
cm - This is the correct location of the Center of Gravity. Achieve the proper CG by shifting
components inside the aircraft. Battery Packs are generally the heaviest items and can be
positioned to achieve proper balance. A "worst case scenario" will require the addition of nose or
tail weight to arrive at the proper CG.
DO NOT FLY UNTIL CORRECT CG HAS BEEN ACHIEVED!
Control Throws
Ailerons and Rudder are mechanically limited by the aircraft structure and should be set for
maximum travel without binding. Flaps should be set for maximum deflection, assuming the flap
pushrod is on the outermost hole of the flap servo control horn (as pictured in the manual). Flaps
should also be set up on a proportional channel on your radio so that any flap setting can be
dialed in. Elevator travel is set to 2 cm up and 2 cm down.
Engine
It goes without saying that your engine must be 100% reliable. If using the 30 inch 4-blade
carbon fiber propeller, set maximum RPM on the ground to 3800. This is achieved by adjusting
blade pitch angle for the proper engine load. IF the engine is not loaded sufficiently via correct
propeller pitch, you risk over-revving the engine and throwing a pushrod in the air.
Idle, transition and top end must be 100% reliable on the ground. It WILL NOT
IMPROVE in the air!
FLYING the THUNDERBOLT
IF using a 100cc or 120cc gas twin, standard set-up and tuning procedures should be used to
achieve reliable operation.
Assuming you are using a Moki 250 and 30" CARF 4-blade propeller, the engine/propeller
combination should be tuned to spin no more than 4000 rpm on the ground – 3800 rpm is
optimal. This is achieved by adjusting the blade pitch; using the Solo prop hub, set the pitch to
14" and test.
Testing your propeller set-up will require balancing the prop/hub combination as well as
adjusting the tracking of the propeller tips to make sure they are as close to aligned as you can
achieve. The proper pitch adjustment must LIMIT full throttle ground rpm to less than 4000!
All of this is REQUIRED if you are to achieve a reliable scale powerplant. Improper balance or
tracking will create excessive vibration. Over-revving the engine can cause it to lose a pushrod at
full throttle!
The Moki 250/4-blade propeller will produce incredible static thrust capable of rotating the
aircraft in less than 100 feet. Once airborne, retract the landing gear, reduce throttle to
approximately 60% and check for proper trim. You should trim the aircraft for hands-off flight at
a reduced throttle setting, then fly it through its full range of power settings to determine if it has
any tendency to pitch up or down.
The Thunderbolt handles very predictably and all flight surfaces are very effective. Although the
finished aircraft will weigh approximately 25kg (50 pounds), it remains fully controllable
through a surprisingly broad flight envelope.
Allow yourself plenty of altitude until you become familiar with the aircraft's handling. Try slow
flight with and without flaps to check their affect.
111
Advertisement
