DBTECH

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Gear

  • Main Canopy Size
    135
  • Main Canopy Other
    Stiletto
  • Reserve Canopy Size
    181
  • AAD
    Cypres

Jump Profile

  • Home DZ
    Skydive Arizona at Eloy
  • License
    B
  • License Number
    21186
  • Licensing Organization
    USPA
  • Number of Jumps
    1220
  • First Choice Discipline
    Formation Skydiving
  • Second Choice Discipline
    Freefall Photography

Ratings and Rigging

  • Pro Rating
    Yes
  • Rigging Back
    Senior Rigger
  1. DBTECH

    Cleaning jumpsuits

    I wash my jumpsuits in my washer with a phosphate detergent, followed by no less than THREE rinses. (use cool to warm water) (hang to dry) NOTE: By far, the most effective dissolver of grass stains is "Clorox Cleanup." It is available in a spray bottle at any food store. Rinse out thoroughly with warm water after use. Dave Brownell
  2. DBTECH

    HMA brake lines

    Currently on one of my new canopies, I am using a Bowline knot at the toggles--until I establish my full flight line length, at which time I may finger trap a 1+ inch loop. (maybe?) BTW-a Bowline will not slip. You could also go with the usual accepted single overhand knot on a looped end. (should not slip) Dave Brownell
  3. DBTECH

    spectra 850 microline

    I appreciate your proper definition of 'proof load,' as compared to 'tensile strength,' which is in fact the actual strength of the said material in pounds per square inch. i.e, Spectra= 400,000 PSI nominal tensile strength. Spectra is in fact 'Ultra High Molecular Weight Polyethylene' (UHMW-PE) (often referred to as the poor man's Teflon) Dave Brownell
  4. DBTECH

    collapsing your slider

    I prefer # 4's over all other Rapide links because they are stronger than 3.5 mini's and smaller than #5's. A slider with #8 spur grommets, or 25 mm stainless grommets will go over a #4 Rapide link with no problem. As a matter of fact, all Atair canopies come as standard, #4 stainless Rapide links that incorporate a piece of 1" type 4 square weave that acts as a grommet protector. Dave Brownell
  5. DBTECH

    Correctly made mini 3-ring riser pictures

    Bill--welcome to the forum ('s) You should also consider posting on the 'Gear and Rigging' forum--also on Dropzone.com. Dave Brownell
  6. DBTECH

    Closing loop

    The minimum breaking strength for Nylon TY IIA flattened line is 225 lbs. A loop would be 550 lbs. 10% of the loop strength would be 55 lbs. I certainly would not want 90% of my closing loop destroyed! I 'was' using the tried & proven type IIA coreless-flattened line, (formally called--PC crown line) for closing loops--I now use Spectra 1000--seems much more durable than type IIA Nylon line. (also, pin pulls easier with Spectra) The following are simple instructions for making a Spectra closing loop. To make a Spectra closing loop--Use a piece of 1000 lb Spectra that is at least 14" long. Finger trap the line into itself from mid length, (end toward end) and bring the loop size down to about 1" laid flat dimension. (use a wire fid/end loop) 'Milk' the line down with your finger in the loop. A 'tack' at the eye bottom is not needed, as both ends of the line will be secured in the knot. Use a figure eight knot for the stop knot. NOTE: Spectra (Ultra High Molecular Weight Polyethylene)-(UHMW-PE) has a much lower coefficient of friction than Kevlar, Vectran, HMA, or Nylon. I guess that's the reason they call it the 'Poor Man's Teflon!' WARNING: Never withdraw a pull up cord that is between a Spectra closing loop and the pin, as melting of the Spectra closing loop can occur. (Spectra has a melting point around 290°F!-Nylon is 490°F. The following is an idea I came up with recently for a Spectra pull-up cord that works very good. (MISS) Using 550 lb Spectra, I configure it into a continuous loop that is 17" long laid flat-that's it--you figure out the rest? Dave Brownell
  7. DBTECH

    Squares for pilot emergency parachutes?

    With a free packed round parachute, the first element to accelerate away from the container is, of course, the apex of the canopy. If we assume a 26' canopy, that would mean a nominal 12 feet between the apex and the diaper. Doing rough math, the apex would be moving away from the rig at 66 FPS (45 MPH) just before the diaper/area starts to accelerate away from the pack tray. If I use one foot for an acceleration distance for the diaper/area, that would mean that the diaper/area, with it's stowed lines, would experience a change in velocity of 66 FPS in 0.015 seconds.(15 ms) This translates to 137 G's nominal acceleration, for 15ms for the diaper/area and it's stowed lines!! Comparing this with a 'bagged canopy' with the lines stowed on it--a bagged canopy with it's stowed lines accelerates at about ten G's at lift off from the container. (pilot chute drag over bag weight-minus one) This translates to ten times more acceleration for the stowed lines on a diapered free packed round parachute, as compared to the stowed lines on a D-bag!! With a horizontal line stow method, large stow bites can all but eliminate the chance of line dump, because of the large mass of the large stow bite outside of the stow band. The applied acceleration force is, of course, 90° to the line passes. With a vertical stow diaper, the lines are 'aligned' with the applied acceleration force-most of which is provided by the top stow bands. It can easily been seen that the line mass below the top stow band is pulling directly down on the top stow band during diaper/area acceleration. When you combine this fact with a ten times factor in line acceleration as compared to a D-bag, you can understand my grave concern here. And then there's the old joke--"You'd be surprised what you can get away with" (even on a reserve parachute!!) Dave Brownell db
  8. DBTECH

    Squares for pilot emergency parachutes?

    Try it on every jump, as the only way this could happen, would be a unique changing wind shear condition from opening altitude to near ground. (and/or a very slow turn in the canopy) Do this also--turn to a down wind heading immediately after opening & see what happens. (same time under canopy not touching toggles) A static air/fluid mass is the same as a huge fish bowl sitting on a parked railroad flat car, or that flat car/fish tank moving at 1000 MPH across the ground. (very smooth road bed, indeed!) Dave Brownell
  9. DBTECH

    Squares for pilot emergency parachutes?

    Thanks for the clarification, as I was about to send you my article entitled--> 'One of Aviations biggest conceptual hangups' Dave Brownell
  10. DBTECH

    Squares for pilot emergency parachutes?

    Eric said: Granted, they are probally going to be down wind since the canopy will want to turn that way in the moving air flow. ------------------------------------------------------------------------------------- Whaaaht!! Looks like someone needs some Newtonian Physics input. Dave Brownell
  11. DBTECH

    Squares for pilot emergency parachutes?

    My current pilot's rig is a Butler Bata container, with a 26' conical-Strong LOPO LITE. I consider the Strong LOPO LITE canopy the best round reserve 'canopy' ever built--to bad that the diaper design is the worst design ever! Yes, it can line dump!!--says allot for TSO's! (just my opinion-of course) As for large ram-air's for none jumping aerobatic pilots, I seem to recall that there is at least one that has no steering lines, and it is trimmed to fly at the same speed as not releasing the brakes. What about having the non jumping aero pilot do simulated landings with the same 'virtual reality system' that George Bush used? It would be recommenced that he/she stay current every six months? Dave Brownell
  12. DBTECH

    Canopy Care.

    Andy said--> Interesting fact, 9000 meters (about 5.5 miles) of canopy thread weights 30 grams (about 1 ounce). DB> You do mean 'canopy fabric thread,' of course. The one thing that is not addressed on the Performance Textiles site, is how to remove a film, of just plain dust, from Soar Coat! My experience is to use a regular cotton wash cloth soaked with cool to warm water-then rung out. Use the entire area of the cloth when cleaning the fabric, and rinse, and ring-out frequently. Unlike many other fabrics, cotton holds dirt much better. BTW: A sponge is the worst in this regard-by a long shot. Dave Brownell
  13. DBTECH

    Pull-Up Chord Material

    825 Spectra is ok, but 1000 should--'at least in theory'-have better longevity. Dave Brownell
  14. DBTECH

    Pull-Up Chord Material

    Plus the fact that Spectra (Ultra High Molecular Weight Polyethylene)-(UHMW-PE) has a much lower coefficient of friction than Vectran, HMA, or Nylon. I guess that's the reason they call it the 'Poor Man's Teflon!' Dave Brownell
  15. DBTECH

    Pull-Up Chord Material

    I would not approve of the use of Vectran or HMA for a closing loop, as both of these Polymers have poor abrasion resistance, along with a 'brittleness factor.' The following are simple instructions for making a Spectra closing loop. To make a Spectra closing loop--Use a piece of 1000 lb Spectra that is at least 14" long. Finger trap the line into itself from mid length, (end toward end) and bring the loop size down to about 1" laid flat dimension. (use a wire fid/end loop) 'Milk' the line down with your finger in the loop. A 'tack' at the eye bottom is not needed, as both ends of the line will be secured in the knot. Use a figure eight knot for the stop knot. Dave Brownell