Pilot 168 (ZP) pack volume vs Sabre2 170

[palejo 0]

Is this a pack volume myth or a true? Pilot 168 (ZP) packs bigger than a Sabre2 170.
Pilot 168: 416 cu. in.
Sabre2 170: 397 cu. in.
I don't understand why when a Pilot 168 (ZP) has F111 ribs and is a couple sq. ft. smaller than the Sabre2 170 (all ZP). Considering same type of lines (Spectre). The Pilot has shorter lines than a Sabre of the same size.

Alejandro
B27585

[GLIDEANGLE 1]

I would guess that the 5% difference in this example is within the margin of error for this measurement.

See discussion of this on pages 4-10 & 4-11 of this document:

http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/media/FAA-H-8083-17.pdf

The choices we make have consequences, for us & for others!

[Quagmirian 40]

I think PD uses slightly lower bulk seams for the Sabre 2.

[faulk04 0]

the pilot is actually bigger than the sabre and it is because of the way they measure it. (PD and Aerodyne measure the sizes of the parachutes differently)

So a pilot 168 is bigger than a Sabre 170, even though you would think it would be the opposite.

We had an aerodyne dealer at our DZ one weekend and I remember him talking about it.




Or at least I think this is right, but I might have been dreaming during his talk

[hillson 0]

Call Wings...they'll know best (they are sized based on a Sabre 2 and a PDR, FWIW).

Dunno where you're getting the Sabre 2 volume from as PD doesn't publish pack volumes. If you're using the PIA Volume chart the numbers in that size are for a Sabre I. In the 170 the range is: 397-445-451.

Aerodyne self-reports 416 for a Pilot 168 and the PIA chart lists 438. Add in different measurements from Para Gear and it gets even less precise.

There are 100s of factors, I'm sure, that can ensure that measurements are off. But you can say they are generally about the same size, volume-wise.

[councilman24 36]

These two numbers are functionally the same assuming they were measured by the same person. The PIA numbers have all been produced by Sandy Reid using the same conditions and equipment. While they may vary from other published numbers they are as comparable as any. Any individual canopy may vary from another identical model/size/make specimen by 10% even when measured by the same person.

While not completely on point the PIA spec for type 7 webbing thickness is 0.08 to 0.12". This is an example of how fabrics, with equal performance, may have vastly different volumes. I don't have the zp spec handy.

I believe the comment about a lower bulk seam is correct although it's been a while since I saw a Pilot. PD's measurement actually results in lower area numbers than the 'normal' measurement used by much of the industry. Without looking I'm not sure what method Aerodyne uses but I believe it's the 'normal' method.

In any rate round these number to the nearest quarter of a hundred (xx0,x25,x50,x75) and recognize that any two adjacent values may in fact overlap. And that depending on any published volume numbers to decide if a canopy will fit in a container when it's at the very top of the recommended volume or model size is inappropriate. At the limit only trying the canopy in the container will guarantee it will fit.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE