HMA Revisted

[timmyfitz 0]

I just spoke with George at Precision Aerodynamics concerning how often the HMA lines should be replaced. I was told that HMA is not like Vectran so they do not need to be replaced as often as Vectran. There were some other interesting facts he told me about HMA which are to lengthy for me to type here. What it boiled down to is that they should be replaced every 600....possibly 700 jumps. He also invited anyone with questions concerning HMA line to call Precision. 423-949-4688

[ianmdrennan 2]

This most definately does not apply to brake lines as I've seen, firsthand, Precisions HMA snap before my Vectran (which is in bad shape and has just been replaced. I'm damn lucky mine hadn't broken yet)

Maybe overall lineset lifetime, but brake snaps are what can kill.

Did Precision talk about brake lines as well?

Blue skies
Ian

Performance Designs Factory Team

[timmyfitz 0]

Unfortunately, I forgot to ask about lower control lines. I have heard they are sending out new canopies with Dacron control lines which may be a sign that HMA control lines do wear more quickly.

I was also told that they are in the process of updating there web page and ask them to include information about the HMA lines ie-replacement time, how to detect wear, etc.

[ianmdrennan 2]

Thanks for passing along the info.

It's awesome to hear that Precision will be posting up more information on the line sets, looking for wear, etc. I hope this is something that more manufacturers do.

Blue skies
Ian

Performance Designs Factory Team

[johnny1488 1]

Quote

I hope this is something that more manufacturers do.

Taken from Icarus' web page. Its not everything but at least it address the problem. It has been there as long as I've been visiting the page.


Spectra:

Spectra line has a limited life and will generally need replacing any where from 300-600 jumps for 500lb line and 500-1000 jumps for 725lb line. Note: your canopy may need re-lining sooner as a result of being out of trim (refer above).

Vectran:

Vectran has become a popular choice due to its superior dimensional integrity. In other words, they won't shrink or distort nearly as much as will Spectra. As a result your canopy will retain better openings and flight characteristics for the duration of the line sets life.


NOTE: Vectran does not have as much abrasion resistance as Spectra, and the lines will "fuzz out" sooner than Spectra

It is recommended that you check line wear regularly. In particular, check out the lower control lines; they wear out fastest.

Once again we recommend a line set replacement anywhere between 300 and 600 jumps but due to the variables involved, we recommend that you pay close attention to line wear and if in doubt at least replace your lower control lines regularly.

The life of your lines will depend on several factors like your weight, the cleanliness of your packing environment, the number of lines (7-Cell or 9-Cell), how well you look after them and the condition of your slider grommets. Linesets should be monitored for wear and trim and retrimmed or replaced as you would a set of tires on a car. The things to look out for are trims, wear spots, snags and worn stitching. Often wear spots can appear quite bad but still retain much of their strength (such as wear by Velcro) and sometimes a line can appear in quite good condition and be weakened considerably (often underneath a fingertrap). A simple test is to squeeze the line between your thumb and finger and slide it along, if the line or wear spot gets thinner it is more than likely weakened. Other common wear spots are the lower brake lines and the corner lines where they meet the connector links. You can monitor the condition of your lines easily while packing, about every 50 jumps have a closer look, If you are unsure of something check with your rigger. One of the best things you can do to improve the life of your lines is to use soft links and monitor the condition of your slider grommets
If your canopy is equipped with brake set loops rather than a cats-eye configuration, check them periodically for wear. These finger-trapped loops are especially susceptible to wear and, if not in top shape, can result in premature brake release.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[Xaosrules 0]

Its probably a reason why PA have changed the lower control lines to 400 p Dacron. If You have an "older" PGZ canopy with lower control lines of HMA and believe they will brake. Change them. Its an easy job and PA will send you new one in a short time.

Better safe then sorry.

[GroundZero 0]

Quote

Did Precision talk about brake lines as well?

The brake lines wear at vastly different rates depending upon the pilot. Look up and watch a bunch of canopies descend. Some take forever, hovering above the pack. Others simply saw through the air back and forth and land well ahead of the crowd. Some jumpers make a few docile turns and others viciously tear up the sky.

That said... at Precision we now (and have been for about 2 months) use Dacron 400 pound line on all lower control lines for all new main (HMA) canopies. While we've seen lower control lines (built of 430 kg. HMA go over 800 jumps, we've also seen breaks earlier. Our decision to go to the Dacron was for the most part to squelch a rumor mill. With one or two reported premature breaks (in the 300 jump range), we saw chicken littles scream from all points. I have never seen an unannounced steering line break, (except with spectra).

Inspect your lines, don't expect your "packer" to do it for you. You fly the canopy. There is no reason you cannot look at your steering lines EVERY jump. If you have excessive wear. REPLACE them!

With these canopies, you can do the replacement without a rigger or sewing machine. Simply untie your toggles, unloop the lower, loop on the new one ane retie the toggle.

Call or e-mail if you have any questions about your lines.

Chris

Precision Aerodynamics
chris@NOSPAMprecision.net
423-949-4688