Merry Christmas!!!

[guest]

Merry Christmas!!!

[guest]

"....peace on earth, and good flickin' to all men (and women)"

Let's keep kickin' it out in the new year!

base587

[guest]

Trying to, but this damn weather south of the Mason Dixon sucks too! It's been blowin cold for 4 weeks now here in Ky.. If (big if) I had a dry suit, I'd inflate my nads and pop a few off the many 180 plus bridges around here to test this Vtec.
To anyone with a great deal of experience with s/l or pca specifically with a Vtec'd canopy, how does the mod measure up to a standard mojo or fox with moderate tail winds, say 7-12 mph with regards to pressurization/sink rate immediately after deployment?? I'd read a few months back about a jumper who was pranged up because of pressurization problems off a 150' bridge and a tailwind or crosswind scenario.
386

[guest]

> To anyone with a great deal of
>experience with s/l or pca
>specifically with a Vtec'd canopy, how
>does the mod measure up to a standard
>mojo or fox with moderate tail winds,
>say 7-12 mph with regards to
>pressurization/sink rate immediately
>after deployment??

I have a number of slider down V-tec deployments in moderate tail winds (up to 30 knots). I also have fairly extensive experience deploying in these conditions with a wide range of other canopies including the Mojo and standard FOX. Often these deployments were achieved in close proximity (my version of close) to the ground and I was able to judge pressurization not only by time taken for canopy to achieve responsiveness to toggle or riser input but also in vertical descent rate after bottom skin expansion had been achieved.

Based on my experiences one of the main concerns when deploying a non V-tec canopy in a moderate-strong tail wind is the extreme variability in altitude loss and time taken to achieve a pressurized/flying/landable canopy after bottom skin expansion.
This is understandable in a tail wind given that on bottom skin expansion the horizontal airflow is moving from the tail of the canopy towards the nose – thereby hindering air entering the nose and pressurizing the cells.
With a V-tec canopy the worst pressurization experiences I have had (in strong tailwind slider down deployments) were similar to the pressurization performance of a static line deployed Mojo in nil wind at sea level (with a 0.7 wing loading).

One example of many: During a recent Xmas Eve experiences a certain doctor and I both jumped the very tip of a crane boom in a 10 knot tail wind (1 sec delay’s). I used a Vtec and the Doc used a Mojo. The difference in pressurization was so different that even our zero-parachuting experienced ground crew noticed ("He was just sinking after he opened, but your parachute just stopped").
Other recent experiences include a 120ft cell phone tower in a 12 knot tail wind during a snow storm. The jump was static lined with a V-tec and I stood up the landing (you have to fly your arse off though).

There is always a degree of random variability when it comes to canopy deployments and pressurization (much more so when the element of wind is introduced). You need to recognize this degree of variability and then incorporate it into the margin for error you build into the jump plan. Obviously if you are using technology with a lower degree of variance then the margin for error may be reduced accordingly and the end degree of risk will be the same (or you can elect to maintain your present margins for error and thereby reduce the level of risk).

The three main factors that determine risk level on a particular jump are
1.The skill level, knowledge base and experience of the jumper,
2.The technology the jumper is using, and
3.The object and the current conditions

We can elect to jump/walk away from objects. We can use whatever resources are available to improve our skill levels, knowledge base and experience. We can also give the manufacturers gentle encouragement from time to time to maintain a healthy level of investment in research and development.

BSBD,
Dwain

[guest]

Nice post Dwain, appreciate it. Gonna stay low, avoid the cold, got a brand spankin new cellular tower 10 minutes away, gonna check this baby out.
Got any pics of this 120'er??
Mike