Newbie question on brake lines and stalling

[Orange1 0]

I hope this isn't a dumb question. I'm still trying to get beyond just the very basics of understanding how a ram-air canopy works!!

Student canopies are "unstallable", if I understand right this is from lengthened brake lines. Why is this rather safe aspect not extended to other canopies - I presume there is a trade-off somewhere between this and better performance in some other aspects?
If I wanted to have my own (as yet unpurchased!) chute modified this way would I be able to, and why would I or wouldn't i want to?

Skydiving: wasting fossil fuels just for fun.

[AggieDave 6]

Think of it like cars, a lot of DZs "detune" their student canopies to make them harder to stall. That way if a student flares at 40ft and stays that way, the canopy doesn't stall and dump the student on their back at 15ft. Although with PD's Navigator, I've even taken the 200 loaded higher then any student would load it and tried to stall it. I still had to take a wrap to stall it, and we have our brake lines set at the factory setting.

As for your gear when you get it. You don't have to be able to stall the canopy, infact some canopies at some lighter wingloadings when set for front riser maneuvers are very hard to stall, it takes taking a wrap on the brake lines to get enough toggle stroke to stall it.

So, the answer is, as long as you're getting a good powerful flare, you don't have to be able to stall the canopy. Scott Miller spends a good amount of time discussing this concept in detail, he's much better at explaining it and teaching it then I am, I would suggest catching one of his canopy courses when you can. In the mean time, in your search for knowledge, get Brian Germain's book. Last but not least, please, as always, talk to your instructors and/or your S&TA about these things. They may point you towards someone esle on the DZ that's a really squared away canopy pilot, but they'll do their best not to steer you wrong.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Orange1 0]

Thanks - have already ordered Germain's book.
Unless Scott Miller decides to visit SA that course may have to wait a while

Skydiving: wasting fossil fuels just for fun.

[AggieDave 6]

Ah, somehow missed the fact that you're in SA...well, he'll go where he's asked and where someone will fly him.

Good luck then, and don't stop asking questions.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Reginald 0]

An interesting question!

I’m not a rigger but I’ll give you what I know. As you mentioned and UTDave
On an experienced skydiver's rig the break lines are usually set so that they are not putting the canopy in partial brakes (too short) especially when pulling down on front risers. You can tell if brake lines are too sort by looking up in full flight and seeing if there is a bow to the lines (okay) or if they are taught (too short). There are additional signals when front risers are pulled down but that is too much to type… In general you want a couple of inches of play in the lines before pulling down on the toggles initiates a turn (way overly simplified but you get the point) but not more (too long).

The flip side of not having the lines too short is that they may be too long to stall the canopy. You want to be able to stall most canopies because on landing you can arrest all the speed possible. This is again a bit of an oversimplification but you get the idea. Do you think a super swooper has the need to do this?

An experienced canopy pilot knows the stall point of his canopy and can work it right up to that point.

Now how does this apply to you and me (I have no desire to swoop at this point)? Your first canopy will probably be so big that unless you set the brake lines so short that it is in partial brakes with the toggles all the way up you might not be able to stall it without taking a wrap anyway. Not a big deal. Your landings will be slow enough that that extra tiny amount of brakes won’t matter much on landing. You will want all the performance you can get in full flight, however.

My brake lines on my 170 are set so that in full flight I have about 2” of play in them (slightly bowed). I can just almost stall the canopy but without taking a half wrap I can’t stall it. My prior canopy, a 190, I had to take a full wrap and a half to stall it. My next canopy, a 150, will probably be small enough that I will be able to stall it without taking a wrap.

This is all way oversimplified and I’m sure someone will point out the errors of my ways, but it might give you a general overview of the issues you are inquiring about.

"We've been looking for the enemy for some time now. We've finally found him. We're surrounded. That simplifies things." CP