Van's Aircraft RV-8 Construction Manual Download Page 156

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SECTION 14

WEIGHT AND BALANCE

RV-8/8A

8-s14r2 12/22/97

14-3

or load combination permitted. Such calculations are always based on the amount of fuel on board during the

most critical

portion of the flight. In other words, if maximum allowable gross weight is the limiting factor, full fuel

imposes the most extreme loading condition, so that figure is used. In another case, where aft C.G. is the limiting
factor, minimum fuel (the condition which could exist at the end of the flight) is assumed.

SOME EXAMPLES

Sample 1 shows a typical RV-8/8A loaded with two FAA standard 170 lb. occupants, full fuel, and partial
baggage; the typical beginning of a trip. The airplane is well within both gross weight and C.G. limits, and as
shown in Sample 2, remains there even when landing at the end of the trip with minimum fuel.

The airplane could be within limits at take-off, but outside the limits upon landing. This instance is illustrated in
Sample 3, where we are carrying more baggage and a heavy passenger and have reduced the fuel to remain
within design gross weight limits. The gross weight and C.G. calculations show everything within limits at take-
off, but as fuel is burned, the CG moves aft and if the trip is continued to the minimum fuel level shown in Sample
4, the airplane will be outside the aft CG limit upon landing. This is a potentially dangerous situation, as an
airplane with the CG too far aft becomes very pitch sensitive and may be difficult to control. A reduction in aft
baggage weight would be needed to attain an acceptable loading condition. By trial and error calculations, we
can thereby establish the maximum baggage permitted under minimum fuel conditions.

In Sample 5, consider a gross weight condition in which a heavy pilot (Bubba) was installed in lieu of the 170 lb.
pilot used in the initial gross weight calculation. Also substituted was an increase in the baggage load up to the
structural limit of 125 lbs. A reduction in the fuel load was needed to remain within the gross weight limit of 1800
lbs. The calculations show that the C.G. will remain within limits for this loading condition.

Following the sample calculations is a blank C.G. form which may be used for calculating the C.G. for

your

RV-

8/8A. Arms for the locations of the standard loads are provided in the sample calculations. If those for your
airplane remain the same, (no changes in the seat locations, etc.) these figures can be used.

The sample

calculations are only representative figures and may not (probably will not) be the same as those you determine
for your RV-8/8A.

While the loads and weights of pilot, passenger, and fuel may be the same, a different empty weight C.G. for
your RV-8/8A could cause the final loaded C.G. to be considerably different. Any variations in the airframe such
as a metal prop or constant speed prop, would considerably affect the empty C.G. Such changes may require
relocation of other items, such as the battery, to keep the empty C.G. within an acceptable range.

RV-8/8A WEIGHTS AND LIMITS - EASY REFERENCE

Recommended Gross Weight

1800 lbs

Aerobatic Gross Weight

1600 lbs (if equipped w/dash One wing) 1550 lbs (w/o dash One wing)

Forward CG Limit

15% of chord

8.7” aft of leading edge

78.70” aft of datum

Aft CG Limit

29% of chord

16.8” aft of leading edge