melushell 0 #1 January 8, 2005 Why the reserve front risers are a different material and thickness than the backrisers ? Quote Share this post Link to post Share on other sites
mark 107 #2 January 8, 2005 The thinner webbing frequently found on the rear risers is strong enough. The thicker webbing on the front risers is more than strong enough for risers, but is the same piece as the main lift web (the front part of your harness), and needs to be strong enough for that. Also, the thicker webbing may continue lower to form the leg strap, so needs to be thick for the friction adapter (leg strap adjuster) to grab and keep from slipping. There are other places in your harness where thinner webbing is probably used. If you look under the reserve risers, you'll see a piece of webbing that goes diagonally over your shoulder down to the middle of your lower back. And there is another piece that goes laterally around your back from one hip to the other. Both of these take less stress, so can be made of lighter materials. Not all reserve risers are made from different thickness materials. On a Dolphin, both front and back risers are from lighter Type 8. And I recently packed another rig (Talon 3?, I don't recall exactly), where both were from heavier Type 7. Mark Quote Share this post Link to post Share on other sites
bliston 0 #3 January 8, 2005 Another reason some companies might choose to use stronger webbing for the front risers is that there is a much larger load placed on them during opening. A manufacturer once told me (I don't have the physics backgroud to verify it) that the majority of the opening load is placed on your "A" lines, then the B, C, D, and brakelines bear less as you towards the tail of the canopy. If I recall correctly, he told me that front risers bear 80-90% of the opening shock. BenMass Defiance 4-wayFS website sticks! Quote Share this post Link to post Share on other sites
mjosparky 4 #4 January 8, 2005 QuoteWhy the reserve front risers are a different material and thickness than the backrisers ? This is a carry over from the days when reserve risers were more exposed to the outside environment, ie sunlight. The theory was that the front riser which covers the rear riser. took all the UV exposer and would degrade somewhat. It was made of Type VII so if it did degrade it would still be as strong as the rear riser made of Type VIII. Thats my story and I am sticking to it. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
riggerrob 643 #5 January 9, 2005 I am going to back up MJOSPARKY, but on the issue of abrasion. Lightweight Type 8 webbing works great - for reserve risers and main lift webs - but it does not last very long. Front risers suffer serious abrasion when they get dragged across the floor during packing. If you install a heavier webbing (Type 7 or 13) then it takes longer to wear out. Have you noticed that tandem manufacturers install additional sacrificial layers where the harness wraps around the front of 3D rings? Quote Share this post Link to post Share on other sites
ryoder 1,590 #6 January 10, 2005 QuoteAnother reason some companies might choose to use stronger webbing for the front risers is that there is a much larger load placed on them during opening. A manufacturer once told me (I don't have the physics backgroud to verify it) that the majority of the opening load is placed on your "A" lines, then the B, C, D, and brakelines bear less as you towards the tail of the canopy. If I recall correctly, he told me that front risers bear 80-90% of the opening shock. Ben The load DURING FLIGHT is biased towards the front, but I don't buy it for opening shock. I have had hard opening shocks that snapped nearly new 1000 lb Vectran steering lines, but did no damage to the 750 Spectra lines. I have also seen cases of nasty opening shocks that tore fabric ONLY in the vicinity of of the trailing edge."There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones. Quote Share this post Link to post Share on other sites
mjosparky 4 #7 January 10, 2005 QuoteI am going to back up MJOSPARKY, but on the issue of abrasion. Lightweight Type 8 webbing works great - for reserve risers and main lift webs - but it does not last very long. Front risers suffer serious abrasion when they get dragged across the floor during packing. If you install a heavier webbing (Type 7 or 13) then it takes longer to wear out. Have you noticed that tandem manufacturers install additional sacrificial layers where the harness wraps around the front of 3D rings? Have you ever noticed that NB series of bail out rigs have riser covers on the front riser? This is to protect the riser from UV when the rig is left in the cockpit on stand-by situations. The riser is the only load bearing portion of the harness exposed. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
