slow flight landing

[d123 1]

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?
I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Regards,
Jean-Arthur Deda.

Lock, Dock and Two Smoking Barrelrolls!

[vdschoor 0]

I think it gets harder and harder to time the flare right with smaller canopies, but I've landed my velocity 103 in half brakes, I prepared for a PLF and I was pretty aggressive in finishing the flare from the half brake point...

[davelepka 4]

Quote

I think it gets harder and harder to time the flare right with smaller canopies, but I've landed my velocity 103 in half brakes, I prepared for a PLF and I was pretty aggressive in finishing the flare from the half brake point...

I agree with that. I also agree that you have to be aggressive, and use every inch of toggle stroke, but the problem is that you need to be extra careful to avoid a stall when doing this.

Half brakes in final will have the nose of the canopy pitched up, and you will be hanging forward of your normal position under the canopy. Both of these factors put you closer to a stall than full flight. Those factors will reduce the amount of time it will take the nose to pitch up enough, or your weight to come forward enough to stall the canopy.

A jumper will be used to a certain magnitude of pitch up, and forward swing when flaring a canopy on a normal landing. When you begin from half brakes, you'll stall well before this magnitude of change is reached. It would be easy to honk down on the toggles, and expect the degree of change/time of change you're used to, only to be dropped on your ass twice as fast as you expect.

The lesson is to fly your canopy around in half brakes at altitude. Work on turns, flares, flare-turns, stalls, and flaring stall-turns. Know how things work, inside and out before doing it right next to the ground.

[phoenixlpr 0]

Quote

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?
I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Sure. The slower you start the harder you land. Why do you want to do that?

Its usually takes from full flight to 1/4 breaks to put the canopy to level flight. Why should I sacrifice the entry speed on purpose? Even after having 90 degrees flat turn on the final 50m I get better landing than from 1/2 breaks.

[phoenixlpr 0]

Quote

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?
I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Regards,
Jean-Arthur Deda.

AFAIK accuracy canopies are designed for sink in in half brakes. Their forward speed is slow in minimal sink rate flight mode.

The smaller canopy you fly the more forward speed is needed to stay on level or in minimal sink rate...

[chuckakers 370]

Quote

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?
I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Regards,
Jean-Arthur Deda.

I don't know about all can be, but I have landed my Velocity at 2:1 in some slow speed modes.

One in particular that comes to mind was a jump where I was returning from a long spot. I cleared the treeline and made it to a clear area near the tip of the runway, but then had a decision to make: land downwind or make a low 180.


The wind wasn't very strong, so I could've done the downwinder. Instead I made a braking 180 and finished the flare in the turn. I don't know if you call that landing "from" half brakes, but it was certainly a minimal performance landing.

By the way, the landing was as soft as any.

I think the real question is at what point does a slow flying canopy lose too much lift to produce a soft landing. Keeping in mind that the lift produced by a wing is the square of the speed. Cut the speed in half and the lift is reduced 4 fold.

Go too slow and pound in.

Chuck Akers
D-10855
Houston, TX

[davelepka 4]

Quote

AFAIK accuracy canopies are designed for sink in in half brakes. Their forward speed is slow in minimal sink rate flight mode.

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

There is no magic that allows an accuracy canopy to sink in. It's simply a fucntion of the huge canopy being able to fly slow enough that even a moderate wind is enough to give the canopy zero ground speed with a little brakes.

They still land like shit in brakes, hence the accuracy tuffet. For those that don't know, a tuffet is a giant round pad with the bullseye in the center, and is in place to keep the jumpers in one piece as they thunder in with little to no flare.

[pchapman 261]

Quote

Quote

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?
I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Sure. The slower you start the harder you land. Why do you want to do that?

I will argue that the answer can be, "Because I was told I'm a bad jumper unless I am able to?!"

For years and years you would see statements saying how you should be able to land any canopy you fly from quarter brakes. This persisted into the era of crossbraced canopies, that even with a small canopy, you aren't able to fly it right unless you can make a landing from quarter brakes.

The concept of landing from quarter brakes was for example in "Parachuting: A Skydiver's Handbook", 2003, but that was aimed at novices and likely thinking of F-111.

Another source is the USPA SIM. The 2007 version says in 6-10:

D. DOWNSIZING PROGRESSION

1. Before moving to a smaller size, a jumper should be familiar and comfortable with the following landing
maneuvers on his or her current canopy:

a. landing flare from full, natural-speed flight
b. flaring for landing from slow (braked) flight
c. consistent soft, stand-up landings within ten
meters of a planned target in a variety of wind
conditions
d. beginning to flare, turning to ten-degree bank,
and returning to wings-level before landing

(My emphasis added.)

No wonder someone asks about the issue. (Although in this particular case the original poster isn't in the USA.) Given the lack of detail in recommendation (b) above, jumpers had better be talking to more experienced jumpers before just going out and trying it.

The partial brake concept is still out there, so it is natural to wonder if an old saying is out of touch with some new realities.

That's not to say that having a little energy in reserve isn't a good thing. It's implied in a lot of those downsizing skills drills. E.g., that one can land one's canopy up hill or with a flared turn or in rougher terrain, that one feels comfortable landing one's canopy in other than perfect conditions. A couple of the well known skills drills, however, don't mention actually landing from a partial brake approach.

While I still see a little value in the quarter-brakes-until-flare idea, I think it becomes less relevant at high wing loadings. It may be sufficient to just recommend being able to

(a) comfortably land from unaccelerated flight, or
(b) do an approach in partial brakes (e.g., when needing to slow things down or exercise glide path control over a bad area for landing), but learn at what point one can go to zero brake, and still have time and altitude to recover speed and plane out properly for a normal landing.

[VictorSuvorov 0]

why do you want to flare from 1/2 brakes?
accuracy? tight landing area?
you can do your final approach 1/2 brakes or even closer to your canopy stall point, release your brakes (if altitude allowes) inducing a dive and build air speed required for an efficient flare.

[phoenixlpr 0]

Quote

I will argue that the answer can be, "Because I was told I'm a bad jumper unless I am able to?!"

For years and years you would see statements saying how you should be able to land any canopy you fly from quarter brakes. This persisted into the era of crossbraced canopies, that even with a small canopy, you aren't able to fly it right unless you can make a landing from quarter brakes.

The concept of landing from quarter brakes was for example in "Parachuting: A Skydiver's Handbook", 2003, but that was aimed at novices and likely thinking of F-111.

I remember similar recommendation about landing in half breaks for the first 2 jump.....
Its stupid and painful. I feel lucky I was not force to do that.

For demonstration of flight abilities I would not go slower than 1/4 breaks. Landing slow is not the only tool at least not in my toolbox. There are stunts that I'm not willing to do any day.

[d123 1]

Indeed, I'm mostly asking with downsize in mind. I want to see what techniques are transferring to a higher WL.

I've finish Safe Flight School while I was in Spain and progressive flare with flare points and slow flight/landings was one of the things that stick in my mind. We had different WL in the class in the range 0.8 to 1.3 and we've been told the we should all be able to safetely land from half brakes. When I did my landing I've pop-up so there was still a lot of lift left.

I want to downsize this year (100 jumps) to 170 so I can do CRW. My plan is to put around 80 jumps on a 190 (1.1) then move to 170 (1.2). I'm still thinking 7 cells.
Knowing that I can still land from slow flight at a higher WL if I find myself in a tight landing area would be really sweet.

In a way it makes sense. Let's say that in full flight you've got a descent speed of 25 km/h. For a tip-toe landing the descent speed should be @ 5 km/h. During flare you're descent speed "decelerates" in 2 sec from 25 km/h to 5 km/h and this acceleration multiply by the system mass gives you the extra lift that your canopy produce during flare.When flying in half brakes the descent speed is smaller so you need less extra lift out of flare to get to a safe landing speed.

That's the theory at least but I know better not to trust a theory over experience hence the questions

Lock, Dock and Two Smoking Barrelrolls!

[d123 1]

One example that goes in my mind is a landing that I've did on my 230 Spectre. Long story short: I've did a helicopter jump and while we're climbing the winds pick up big time. We took a long time to exit and meanwhile we were drifting downwind. I've open over forest with no penetration. Find a small "clear" place (20mx30m) and went to land. It look clear but it was not. It had a swimming pool in construction. I've manage to land OK and now I'm wondering what if I downsize and I find myself again in similar spot? In that case slow flight landing sounds good especially since I will not need to much space for the flare to burn the horizontal speed (landing distance).

Lock, Dock and Two Smoking Barrelrolls!

[phoenixlpr 0]

Quote

In that case slow flight landing sounds good especially since I will not need to much space for the flare to burn the horizontal speed (landing distance).

You may burn your speed faster in a flare turn.

[pilotdave 0]

Quote

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

I completely disagree there. I've jumped a Manta 288, Icarus 330 tandem (solo), and a Classic 218 (acc canopy). Size is not what gives an accuracy canopy it's ability to sink. It's all about the design of the canopy. Acc canopies fly nothing like other big canopies... at least not in brakes. Sinking an accuracy canopy is a really weird sensation... very uncomfortable to me. Especially uncomfortable when I missed the tuffet and sank it right into the ground. My tailbone still hurts from that accident last summer.

A normal canopy can be flared from half brakes. An accuracy canopy cannot. That was my mistake. I should have let go of my toggles and let it surge forward and PLF (probably on the tuffet too). Instead, when I realized I was short of the tuffet and in brakes, I finished my flare. That did the exact opposite of what I wanted to do. The canopy didn't stall... but it just sank faster and slammed me into the ground. It happened so fast I thought I was fine and then suddenly I was on the ground in pain.

Dave

[gravitysurfer 0]

Quote

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

It's a bit unsettling for me to read that statement from a jumper with your posted experience level.

aloha.

[phoenixlpr 0]

Quote

Quote

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

It's a bit unsettling for me to read that statement from a jumper with your posted experience level.

Not everyone is jumping accuracy canopies these days.
I got lots of jump as a student. I just don't want to jump those anymore.

[gravitysurfer 0]

Not sure if you are replying to me but my comment was towards davelepka's post.

aloha.

[davelepka 4]

Quote

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

--------------------------------------------------------------------------------


It's a bit unsettling for me to read that statement from a jumper with your posted experience level.

Why? All ram-air canopies work the same way - the incoming air pressure inflates the cells, creating a wing than can be steered, braked and flared, and possesing a min. air speed for maintaining pressurization and flight (aka the stall speed). This description fits everything from the Para-Foil to the Velo.

There are differences between accuracy canopies, and other canopies - aspect ratio, number of cells, line type and trim, but those differences exist among all types of ram air canopies. Any differences between accuracy canopies and others are not exclusive to accuracy canopies, they are differences that are common among all canopies.

It is the square footage (and the accordingly slow stall speed) that makes it possible to 'sink in' an accuracy canopy. Come in high over the bullseye, once you are centered up, apply brakes until the wind speed matches your air speed. Now you are going straight down, "sinking it in" down onto the bullseye. Even with the generous square footage, the impact upon landing is not slight.

This would work with any canopy provided you had enough wind, and a soft enough place to land.

[phoenixlpr 0]

Quote

Why? All ram-air canopies work the same way - the incoming air pressure inflates the cells, creating a wing than can be steered, braked and flared, and possesing a min. air speed for maintaining pressurization and flight (aka the stall speed). This description fits everything from the Para-Foil to the Velo.

Sure. Consider 3 canopies eg. 220 sqft range, made from low cfm material. Let it be an accuracy, a CRW and an all-around. Land them in the sink-in way. Your legs can tell the difference. I guess this way size is out of question.

[davelepka 4]

Quote

Your legs can tell the difference. I guess this way size is out of question.

Different? Yes.

All suck? Also yes.

How about this - if you built me a 103 sq ft Para Foil, I would not try to sink it in. Why? It lacks the feature that I am proposing makes an accuracy canopy 'sink-able' - it lacks huge-ness.

[DrewEckhardt 0]

Quote

Can any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes?

Yes.

Quote

I know it works for lighter WL (I've landed mine) but how does this scale with higher WL?

Works fine at 1.8 pounds/square foot. It's just harder to get right than a full-flight landing.

[Pendragon 1]

I thought it was because the accuracy canopy was large and low aspect ratio that allowed you to sink it in. Lower aspect 7-cells have a slower speed stall characteristic than conventional 9-cells, making them ideal for this.

In answer to the flaring from 1/4 brakes: it's not quite what it seems. It's actually flaring from a toggle position in which the slack in the brake lines has been taken out, but no input has been made - so you can flare faster when you need to.

--
BASE #1182
Muff #3573
PFI #52; UK WSI #13

[pilotdave 0]

Quote

It is the square footage (and the accordingly slow stall speed) that makes it possible to 'sink in' an accuracy canopy. Come in high over the bullseye, once you are centered up, apply brakes until the wind speed matches your air speed.

I guess we'll agree to disagree. Sure, with enough wind, a velocity will sink straight down. But aerodynamically, it's completely different from what an accuracy canopy is doing. An accuracy canopy can sink in zero wind. Even downwind. A Velocity 238 wouldn't be able to sink like a Classic 238. An Icarus 330 will not sink like a Parafoil. It's not about size, it's about canopy design.

Sure, a classic 99 would probably fly like shit. It's designed for a wingloading of about 0.7. You can't scale down an accuracy canopy to make a swooping canopy and you can't scale up a swooping canopy to become an accuracy canopy. They simply have extremely different flight characteristics due to design differences.

I'm guessing you've never tried classic acc. Try it... you might be surprised how different it is from just jumping a big student canopy.

Dave

[DrewEckhardt 0]

Quote

It is the square footage (and the accordingly slow stall speed) that makes it possible to 'sink in' an accuracy canopy. Come in high over the bullseye, once you are centered up, apply brakes until the wind speed matches your air speed.

You can bring a big fat airfoil seven cell straight down in zero wind. Landing in pea gravel it will be comfortable if you don't do it for too long.

You can come in very steep on hard ground without wind which is useful for landing areas with obstacles at both ends.

Going too far makes the canopy go backwards with the pilot chute above the canopy with a descent rate that would suck on landing.

Quote

Now you are going straight down, "sinking it in" down onto the bullseye. Even with the generous square footage, the impact upon landing is not slight.

245 square feet, 210 pounds of tubby skydiver and big rig (bigger would be better), pea gravel, 45 degree 2/3 brake approach ending with maybe 8' of straight down sink is good for a nice standup. Not like the same skydiver weighing under 160 pounds without gear under a 24' Paracommander (oof).

[DrewEckhardt 0]

Quote

Quote

Quote

Accuracy canopies are designed to fly like every other canopy. The primary difference is that they are huge.

It's a bit unsettling for me to read that statement from a jumper with your posted experience level.

Not everyone is jumping accuracy canopies these days.
I got lots of jump as a student. I just don't want to jump those anymore.

A fresh fat airfoil seven cell canopy is NOT the same thing as a ragged out student canopy approximating what a recreational skydiver would jump just bigger.

Quick turns are out of the question but it will give you a tool that gets you into tight landing areas 100/100 times with accuracy measured in inches instead of meters.