Ride criteria vs pitch motion

[NormPeterson]

I've been tinkering with a spreadsheet to estimate pitch response and would like to tie the results to some basis for acceptability. It seems to me that the rate of change in fore/aft acceleration experienced by a point at approximately head location might be one direction to take, based on the notion that it's a more difficult and less accurately performed task for the body to accommodate changes in the effort required to maintain the head in position than to simply resist a large but constant acceleration.

1. Is this approach at least remotely on the right track?

2. If so, are there any generally accepted maximum values for pitch jerk? Would they likely be unsymmetrical, forward vs rearward?

3. If not, ???

TIA

Norm

 

[NormPeterson]

Thoughts?

Norm

 

[GregLocock]

I think you are on the right track, but I've never got into using jerk.

However, we do effectively use jerk as a ride tuning aid laterally, this controls the amount of sta bar allowed for a given spring rate. aka head toss

For longitudinal acceleration we just set a pitch gradient (deg/g), I guess if that is small enough then the third derivative takes care of itself.

Cheers

Greg Locock

 

[NormPeterson]

Thanks, Greg.

Looks like my next step is to run through a derivation starting with some semi-arbitrary value for pitch gradient and see what turns up. Hopefully, that'll support a "gut-feel" number as being at least reasonable.

Mention of jerk in connection with lateral interests me as well, particularly when elsewhere nobody seems comfortable discussing roll in detail beyond spring stiffnesses, sta-bar diameters, and (occasionally) roll gradients. Maybe it's a subject for another spreadsheet . . .

Norm