AggieMike88
New member
A discussion about calculating weight and balance and the hazards of a CG's too far forward and to far aft had me wondering something...
During the discussion, I asked about how reducing the weight of a particular aircraft might offer an increase in ground speed. Another pilot answered, "Probably faster, but it depends on the weight removed, where you put everything, and the exact characteristics of the plane. While you have reduced gross weight, which will increase speed, you’ve also moved the cg forward, which decreases speed. Sometimes you actually go faster by adding weight way in the back as this moves the cg aft – my airplane racing friends often use ballast of 50-75 lb in the back of the baggage compartment to increase speed"
Currently, I'm piloting a 1975 C182P. We've talked on the forums a few times about 182's that adding ballast to the baggage area can improve handling when the scenario is single pilot or pilot plus passenger and unoccupied rear seat and empty baggage area. Essentially we're moving the CG aft a few inches from where it would be without the ballast. And what this accomplishes is finding a handling "sweet spot"
To me, it appears reasonable that the following items are true
During the discussion, I asked about how reducing the weight of a particular aircraft might offer an increase in ground speed. Another pilot answered, "Probably faster, but it depends on the weight removed, where you put everything, and the exact characteristics of the plane. While you have reduced gross weight, which will increase speed, you’ve also moved the cg forward, which decreases speed. Sometimes you actually go faster by adding weight way in the back as this moves the cg aft – my airplane racing friends often use ballast of 50-75 lb in the back of the baggage compartment to increase speed"
Currently, I'm piloting a 1975 C182P. We've talked on the forums a few times about 182's that adding ballast to the baggage area can improve handling when the scenario is single pilot or pilot plus passenger and unoccupied rear seat and empty baggage area. Essentially we're moving the CG aft a few inches from where it would be without the ballast. And what this accomplishes is finding a handling "sweet spot"
To me, it appears reasonable that the following items are true
- When the aircraft was designed, the designers determined there was a certain angle of attack on the wing that produced the greatest amount of efficiency while in cruise. And this particular AoA would provide all the lift needed, and also achieve a "least drag" state.
- As you move the CG forward and aft, you're also changing the AoA on the wing by a particular increment that might be outside of this "least drag" state.
- Additional drag reduces speed and fuel economy.
- If you knew how far from the datum this "least drag state" CG was, you could work your loading problem to achieve a best speed and best fuel economy condition.