Multiple Masses

[MotorCityMike]

The way the rules are written under 3.b "The launching force must be entirely supplied by the gravitational potential energy from a falling mass less than or equal to 3.5kg (Div C); 5kg (Div B).... This leads me to believe that whatever mass is in use at the time of launch must fulfill the weight limit.

Can a team have multiple, individual use masses, from which only one mass will be used in their launch, and how should this be taken into consideration for weighing purposes?

We have 3 individual masses for our rig, but only one is used at any given time based on the target. We ran into a situation over the weekend at an Invitational where the Air Trajectory ES would not accept that only one mass would be used a given time and thus weighed all three masses together as one.

[Krish2007]

The way the rules are written under 3.b "The launching force must be entirely supplied by the gravitational potential energy from a falling mass less than or equal to 3.5kg (Div C); 5kg (Div B).... This leads me to believe that whatever mass is in use at the time of launch must fulfill the weight limit.

Can a team have multiple, individual use masses, from which only one mass will be used in their launch, and how should this be taken into consideration for weighing purposes?

We have 3 individual masses for our rig, but only one is used at any given time based on the target. We ran into a situation over the weekend at an Invitational where the Air Trajectory ES would not accept that only one mass would be used a given time and thus weighed all three masses together as one.

It seems to me like this is allowed only if the sum of all masses (including those that are not currently in use) is less than 3.5 kg (or 5 kg in div B). 3.b. states that "The falling mass may consist of multiple discrete parts, which together count as the total mass", so I think that all of the masses you could possibly use for your falling mass are included in this measurement. This FAQ also states something similar, and if I understand right, it addresses exactly what you're talking about. Even if only one counterweight is being used, all counterweights that you might use or impounded for this purpose are counted towards the weight limit. Instead of using 3 different counterweights, you could instead have one container and impound many smaller weights that you can add to the container to adjust the weight.

[Northridge]

The way the rules are written under 3.b "The launching force must be entirely supplied by the gravitational potential energy from a falling mass less than or equal to 3.5kg (Div C); 5kg (Div B).... This leads me to believe that whatever mass is in use at the time of launch must fulfill the weight limit.

Can a team have multiple, individual use masses, from which only one mass will be used in their launch, and how should this be taken into consideration for weighing purposes?

We have 3 individual masses for our rig, but only one is used at any given time based on the target. We ran into a situation over the weekend at an Invitational where the Air Trajectory ES would not accept that only one mass would be used a given time and thus weighed all three masses together as one.

Per the rules, you are only allowed to impound the maximum allowable mass for each division (3.5 kg for C, 5 kg for B). This means your 3 mass combined can be no more than 3.5 kg for C or 5 kg for B.