Basejumper.com - archive

A question for the experienced people out there:-

I'm interested in doing a FJC in the US at some point (once I've recovered from the cost of my last trip !!)

I'd like to start to prepare now (especially as I only have 220 jumps) by learning how to pack and fly a base canopy (as well as trying to work on my tracking etc).

My idea is to purchase a canopy and container and then practice by using the base canopy as a main when skydiving.

My questions are:-

1.Can anyone reccomend a canopy (and size) that would be suitable (I'm 190 lbs plus equipment) to learn on. (Troll/Fox/Other)

2.In the first rig article by Tom it states that secondary vents are not a good idea (for a beginner) because of the possible effects of these vents including opening backsurge in deep brakes - is this still the general consensus ??

3.Can the (base) canopy manufacturer give me an idea of pack size so that I make sure I get the correct skydiving container sized for the canopy (it's definately not going to fit my J3!!!)

4.Would a rigger be able to check that I've set the slider and PC up correctly (for skydiving)??

5.Or am I best to wait until I've saved up and done the FJC??

From what I have read - most people seem to suggest that getting used to the canopy control and packing methods as early as possible is the way to go ....

Many thanks ...

Textbook BASE wingloading is .75 lbs/sq.ft. For 190 lbs, that's:

190 body weight + 25 pounds equipment = 215 exit weight
215 / .75 = 286.67

So, a canopy around the 290 range. That includes the following canopies:

Ace/Blackjack 280 or 310
FOX/FOX Vtec 285
Flik/ Flik Vtec 293
Troll/Troll MDV 290
Dagger 277

Any of these canopies would be fine. At this point, my personal recommendation would be a Troll MDV 290. My second choice would be the FOX Vtec (no covers).

While my personal favorite canopy is still the Blackjack, I've heard reports of inflation trouble from experienced, reliable jumpers on both the Ace/Blackjack (on subterminal slider up) and the Flik Vtec (on go and throw slider down). If you want a more detailed discussion of my canopy preferences, start another thread and I'll dig deeper into the issue.


I don't think so. I wrote that last fall, and at this point I think that secondary inlets have had enough field experience to recommend them for most jumps and jumpers (the rare exception being things like wingsuit only jumpers, where they would add to weight and cost without any real benefit). At the moment, of the four canopy manufacturers (Vertigo, CR, BR, Morpheus/Atair), two recommend secondary inlets for beginners (BR and Morpheus) and two do not (CR and Vertigo). The consensus among other experienced jumpers seems to be about 80% for secondary inlets for all jumpers (beginners and experienced jumpers alike).


Certainly. The skydiving container manufacturer should be able to help, too. Remember that if you have valves in your canopy, it's going to be slightly larger than a similarly sized 7 cell skydiving canopy, so you'll want to estimate a bit on the high side (maybe do something like assume the canopy will be a 9 cell in pack volume). Roughly, you'll want something sized J7NK or J8K on the Javelin chart.

For exact numbers pack volume, check with the canopy manufacturer, then call the container manufacturer and give them the numbers.


Certainly.


As far as BASE goes, you're best off to start getting as much practice on the BASE canopy as possible, right now.


Definitely.

1.
190 lb naked plus about 25 lb of equipment (rig+shoes+helmet...) makes 215 lb suspended weight: in order to have a load of 0.75 lb/ft² or less, I would advise the following parachutes:
1) Fox 285÷315 with Vtec+covers
2) Flik 293÷322 with Vtec+covers
3) Black Jack 280÷310 (already includes PAC valves)
4) Troll 290 with MDV valves
Which brand of the above is quite personal, ask more around. Which size of the above, the bigger size would make you fly slower, which is such a good thing


2.
See above: order any parachute of the above that you like best but please order it WITH valves. Valves are an incredible help/tool for having an immediately (after opening) steerable canopy that is mandatory to have: something that greatly helps you to avoid an immediate object strike must be used. A properly braked parachute with valves would just open great, back surge effects are caused by not properly set brakes.

3.
Yes, they can. From Consolidate Rigging web site we have the following pack volumes:
Mojo 190 393 in³ - Mojo 220 468 in³ - Mojo 240 496 in³
Mojo 260 536 in³ - Mojo 280 578 in³ - Mojo 310 685 in³
Consider that, for what concerns BASE parachutes, we can say that parachutes of same size from different manufacturers have (roughly) the same volume, so I extrapolated the following table for Fox parachutes:
Fox 185 386 in³ - Fox 205 428 in³ - Fox 225 470 in³ - Fox 245 512 in³
Fox 265 554 in³ - Fox 285 595 in³ - Fox 315 696 in³
With the above figures, any (skydiving) rig manufaturer and/or (BASE) manufacturer will be able to help to choose the right container to fit the right BASE canopy. Consider also that a Fox 245 fits quite well into a J5 javelin (into a J4 a Fox 245 fits, but it is very very tight indeed!).

4.
Yes, indeed. In the end, a BASE parachute, for what skydiving is concerned, is a "normal" 7 cell F111 large canopy. Please, consider that you must use either a BASE bridle with 1 pin or a standard skydiving bridle and a 28" ZP PC or so. Forget about using a large (36" or so...) BASE PC for skydiving.

5.
No, I would say that it helps a LOT if you buy a BASE parachute of the proper size for your weight and you start to BASE pack it into a skydiving container and put a lot of skydives on it. It gives lots of pratice of BASE packing, of flying your BASE canopy in a safe environment, and indeed a lot of fun trying to do accuracy landing with it!!!

> From what I have read - most people seem to suggest that getting used to the canopy control and packing methods as early as possible is the way to go ....
Yes, this is my opinion too!!! I did something like 30 skydives with my Fox (BASE packed) before doing my FJC.

oh man im confused now. I thought valves helped flight characteristics, i.e. better glide angle, better flare (less mush from vent only). I thought VENTS helped with being able to have a steerable canopy quicker. Is that wrong?

No, that is correct.

Vents improve inflation characteristics but degrade flight performance. Valves help to counteract the negative effects of vents (i.e. return flight characteristics to normal). I'm sure that 689 knows this, but you must realize that he is writing in a foreign language (still, I bet his English is quite a bit better than your Italian).

On the subject of valves: I do not believe that all valves are created equal. Some of the valve systems, while doing very well in flight, still significantly inhibit airflow into the canopy, thereby reducing the positive effects of the vents. I believe the Mono Directional Valve (Atair/Morpheus Troll canopy) is clearly superior to either the BR (vtec "cover") or CR (PAC valve) valve systems.

In fact, all valves will inhibit inflation to some extent. If you wanted to create the fastest, cleanest pressurization possible, you would remove the valves and simply jump a canopy with vents in the bottom skin (no covers). (You'd also want to monkey with vent size, placement and construction, but that's another issue.)

In my opinion, pretty much all the valves on the market seal (with negligible outflow) in flight.

Let's clarify. There is a big misunderstanding here.
Let's explain how things are.
Vtec have been introduced first by Basic Research on Fox parachutes as an option. Vtec are vents(= rectangular holes) on the bottom skin just in front of B line attachment. Such vents helps the air in during primary inflation allowing immediate pressurization of paracute (you have an immediate steerable parachute bla bla bla...).
But vents are just vents, holes I mean. As the air can go in at the same air can go out, in case of turbulence during flight, in case of flare on landing, during the flight itself a lot of air escapes out of the canopy through the vents. Such a secondary effect is a negative effect.
Vtec "ONLY" are just vents = holes.
Then it came Consolidate Rigging/Adam who was studying his own system of vents/valves/whatever. Already aware of the negative effects of vents-only parachutes, he succeeded in developing his PAC valves, pressure activated and controlled valves. PAC are vents that have got in the inside of parachute a piece of "cloth" that allows the air to go in but stops air from going out (more or less effectively).
Then it came Atair that introduced as an option to their Tool, their MDV (mono directional valves) valves. MDV valves are vents that have got in the inside of the parachute another differently shaped (funnel shape) piece of cloth that lets the air go in but stops air from going out.
Then it came BR who had by now developed their own system of valves on their Fox's and Flik's, introducing Vtec+covers. Vtec+covers are vents that have got in the inside of the parachute another piece of cloth that lets the air go in but stops air from going out.
So.
Any time we are speaking about Vtec "only" we are speking about parachutes that have got only vents (= holes) in the bottom skin (air can go in but can also go out).
Any time we are speaking about Vtec+covers and/or PAC valves and/or MDV valves and/or any other type of valve, we are speaking about parachutes that have got vents (= holes) in the bottom skin plus a certain type of valve inside the parachute that allows air to go in but stops air from going out.
Vtec "only" helps in having a steerable canopy quicker.
"Valves" helps in having a steerable canopy quicker too.
Vtec "only" have the downside of having poor flight characteristics, poor flaring power during landing and could deflate the canopy in turbulence.
"Valves" helps in not degrading flight/flare perfomance because of the vents (=holes).
Vents = only holes
Valves = vents plus valves
Valves have all the benefits of vents-only and no downside (theoretically if the valve were "perfect" )
Is that clearer now?

so how much will i notice this in my opening if/when i get my valves done to my Fox 265 vtec? will it open slightly slower or do i get it wrong?

it takes some practice to land a vtec no valves nice(well my oppinion so far/30 jumps on this one)

You have to understand my position as someone that doesnt BASE jump and is in the stage of gaining knowledge/info and when I see a language mistake/typo that counteracts how I thought things were I have to question it for my sake (whereas other experienced jumpers might just recognize it for a mistake I do not have the experience for this). Your knowledge is listened to with respect.

I ringraziamenti 689. L'apprezzo. (I probably butchered that sorry ).

specialy at goes and throughs that worryes me. i have this nice 180ft basket at my A i love to freefall,but if i should get slower openings on my canopy i wont get valves...( in that alti i think it opens slow enough at this point)

> You have to understand my position as someone that doesnt BASE jump and is in the stage of gaining knowledge/info...
No worries, mate!

> Your knowledge is listened to with respect.
Thanks

> I ringraziamenti 689. L'apprezzo.
Correct Italian language. Thanks so much again

Remember, never stop asking. Ignorance is something than can kill you in BASE.

Thanks to Base 689 and Tom for those helpful answers ...

I'll certainly be going for a big-boy canopy (got to leave the pies alone!!!) and will start to do the legwork on costs etc ... And you've cleared up the vented / non-vented query for me !!!

I realised that the choosing your gear article was written a year or so back and thought I'd try to get the most up to date information I could - and from people who have a much better idea of the potential pitfalls and best practices when it comes to learning the art of base !!!

Especially as the odds of demoing canopies like this are low !!!

The last time I made a "blind purchase" for equipment was a snowboard which everyone raved about but as far as I was concerned (once I'd used it a couple of times) - it sucked !!! and I sold it afterwards with probably a weeks worth of use - which was a pretty expensive mistake to make - with base canopies the risks seem greater and not all to do with money !!!

I'm in the US for a couple of days just now and I'm coming back through in a couple of weeks (but it looks like I'm going to miss BD !!!) but I might try to get hold of a canopy if anyone's got one in stock (although this close to BD it might be doubtful) !!!

Anyway - the sooner the better ...

Can't wait to start making those accuracy jumps !!!