Max 0 Fuel Weight RV7A

[Tcheairs]

I'm trying to setup the weight and balance feature of my RV7A in Foreflight Basic Plus. The program wants to know the max 0 fuel weight of the plane. Would that be the empty weight (1167lbs for my plane)? Also wants to know the max ramp weight, max takeoff weight and max landing weight which I assume to be 1800# in the normal category.

Why it want's to know ZFW I don't understand.

Thanks

 

[BobTurner]

Some aircraft designs consider that the weight of fuel carried in the wings helps to resist the bending moment on the wings, and hence is ‘good’ from a structural load standpoint. For example, some aircraft with optional tip tanks are granted an increase in allowed gross weight, equal to the weight of the tip tank fuel (and only allowed when that extra weight is in the tip tanks). None of this applies to your RV, so your max zero fuel weight is 1800 lbs.

 

[Skysailor]

Max zero fuel weight

To determine the maximum zero weight for your plane subtract the weight of all fuel from the aircraft gross weight. Maximum zero fuel weight is defined as the weight of the aircraft above which all added weight is fuel. It is quite commonly used in airline operations.

 

[scrollF4]

To determine the maximum zero weight for your plane subtract the weight of all fuel from the aircraft gross weight. Maximum zero fuel weight is defined as the weight of the aircraft above which all added weight is fuel. It is quite commonly used in airline operations.

...and it does include engine oil and engine coolant (if your engine is liquid-cooled...mine ain't ).

 

[Southern Pete]

I agree with #2, 1800lb for everything as only the max weight is important.
The other quantities are important for larger aircraft.

 

[David Z]

I agree that 1800# is the technically correct answer. However, what is the practical answer?

To actually operate at a 1800# ZFW, there is no fuel left. Enough fuel for a trip around the pattern and land with 30 minutes, say 5 gal. That's 30# of fuel and 1770lbs of airplane, bags and people to be at MTOW. Would a "practical" ZFW limit be closer to 1770lbs?

Going back to the OP, I'm going to disagree that the max ramp weight is 1800lbs. If MTOW is 1800, that cannot be achieved without starting the taxi slightly higher weight. Van's hasn't published a max ramp weight, just a MTOW. Is it safe to assume we can taxi at 1810lbs to account for the run-up and taxi?

 

[Taltruda]

To determine the maximum zero weight for your plane subtract the weight of all fuel from the aircraft gross weight. Maximum zero fuel weight is defined as the weight of the aircraft above which all added weight is fuel. It is quite commonly used in airline operations.

This isn’t correct.. the “Max Zero Fuel Weight” is the max your plane is allowed to weigh, and any additional weight over must be fuel. The RVs don’t have such a limitation. I understand why you would interpret this to take max gross, and subtract 42 gallons of fuel, but that isn’t right. With this mindset, you could never takeoff with a reduced fuel load, yet have two large adults and baggage, keeping under gross weight (which you can do and is done all the time.)

I agree to set this number in foreflight to 1800 lbs for the -7.

 

[RV8JD]

Going back to the OP, I'm going to disagree that the max ramp weight is 1800lbs. If MTOW is 1800, that cannot be achieved without starting the taxi slightly higher weight. Van's hasn't published a max ramp weight, just a MTOW. Is it safe to assume we can taxi at 1810lbs to account for the run-up and taxi?

Van's publishes a Recommended Maximum Gross Weight, not an MTOW. (But I don't think the airplane will sweat the weight of the extra fuel used to taxi for TO in your example above. The landing gear will probably take it. )

Folks need to quit thinking in terms of MTOW, MLW, MZFW, etc., for these light single engine GA airplanes. They just don't apply.