Weight And Balance - Skyranger Nynja Manuel De Montage

24.4.6 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 (full power is not required,
half max rpm should be sufficient); 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.

24.5 Weight and Balance

A weight and balance spreadsheet is included on the CD to assist you.
Note that the weighing attitude is critical on a tall aircraft like the Nynja, and that
bathroom scales are notoriously inaccurate. Typical weights are around 265kg for a
fully equipped four-stroke example, give-or-take 5kg or so.
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 450kg
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
450kg MTOW must be complied with to automatically guarantee that the CG remains
within limits.
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Nynja Manuel de montage Version 5