Flylight Nynja Build, Manual

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Nynja Build manual 1.0
26.6.6 Fuel flow measurement
This should be performed with the help of your inspector who should have suitable
equipment or access to such. Connect a T-piece into the fuel line near the
carburettor(s). Connect this to a fuel pressure gauge and a fuel tap, using a length of
pipe long enough to reach back into the cockpit.
The fuel flow rate may then be measured: run the engine at full power (aircraft will
need stoutly securing for this
– and mind the propwash doesn‟t do any damage to
aircraft or objects behind!) with the end of the fuel pipe pointed into a measuring jug
in the cockpit, open the tap until the fuel pressure drops to no less than the minimum
specified in the engine instructions; measure the time required to bleed off 1 litre of
fuel into the measuring jug. Note 1 bar = 100kPa = 15psi roughly.
The excess fuel flow rate is calculated by dividing 3600 seconds by the number of
seconds taken for 1 litre. This is required to be greater than 25% of the full power fuel
consumption, typically 20-30 litres per hour depending on engine type. Therefore an
excess fuel flow rate around 5 litres per hour or greater is required. Much greater flow
rates than this minimum are normally found.
An alternative method is to arrange a separate fuel tank to supply the engine by
gravity feed, whilst measuring the amount of fuel the pump supplies into a measuring
jug beneath the aircraft (use an extension tube on the fuel line, don‟t try to hit the
bucket from the engine!). This then gives the entire fuel flow rate, which must be
greater than 125% of the full power fuel flow rate.
26.7 Weight and Balance
A weight and balance spreadsheet is included on the CD to assist you.
The aircraft will have to be weighed with the assistance of your Inspector, using the
information given in the HADS. Note that the weighing attitude is critical on a tall
aircraft like the Skyranger, and that bathroom scales are notoriously inaccurate.
Due to the seat weight limits and fuel capacity being greater than the minimums
required, plus the option of the baggage bag, the weight and balance spreadsheet is
likely to show CG limits being exceeded at loads considerably above the 450/
472.5kg MTOW. To resolve this the BMAA technical office has suggested that the
max seat loads entered on the spreadsheet are reduced from their 120kg per seat
value until the CG is within limits. This does not affect the actual max seat load, but
note that the 450/472.5kg MTOW must be complied with to automatically guarantee
that the CG remains within limits.