FreeFlight Advice: Single suspension harnesses
Originally posted on FreeFlightAdvice.com - September 5, 2013
Q: What is the best Single Suspension Harness that does not compromise ease of landing?
A: Well, Cal… whether you meant to or not, you kind of asked two questions at the same time! The first being, what is the best single suspension harness… and the second being which SS harness does not compromise ease of landing.
I’m going to answer the second part first, and come back to the first part. Unfortunately, there is NO single suspension harness that does not compromise ease of landing. That is not to say some are more forgiving than others… but they all trade forgiveness for performance (like most things in hang gliding!).
Let’s look at why that is. The most obvious is because your body is connected to the glider, which is controlled through weight shift, by a single point. This means there are a whole slew of bad habits that will work ok in a more traditional harness, but are ineffective in a single suspension harness. The single point gives the harness- and your body- less stability. You can rock head up/head down, and even roll your body around, with little actual input transmitted to the glider. In turbulence a less experienced pilot will get rocked around a lot more than in a traditional harness. All of the above can be overcome, but remember we’re talking about what compromises are made in order to hang from a single suspension point.
A less intuitive reason SS harnesses are less forgiving is because of the requisite frame or back-plate… and slider. Comfortably hanging from a single point requires spreading that load across as much of your body as possible. Some harnesses have an internal frame to accomplish this, while others use a composite back-plate. They are a necessary evil, but the rigidity they provide while laying prone hinder movement when landing. In a traditional harness, when you rock upright you can sink down into the leg loops, and the upper body of the harness scrunches up a bit. Sinking into the leg loops effectively moved the connection point of the harness mains forward on your body, which makes your body balance in an upright position- even hands off the glider. With a frame or back-plate in the harness, if you sink into the leg loops the harness can’t scrunch up, so the frame/plate will hit you in the back of the neck or head. To allow you to get upright at all, the hang point needs to be able to move forward- and that is why the slider mechanism is required. The slider mechanism is basically a work-around of an issue created by having a frame or back-plate, which is a work around of having a single suspension point.
The slider mechanism is another big reason single suspension harnesses are less forgiving when landing. And it’s really a two-fold “problem”. When you rock upright and the slider moves forward, you are now hanging lower in the control frame. Hanging low is a “problem” because it effectively shortens your arms when it is time to flare. If timed perfectly, it’s actually possible to flare to a complete stop- even in no wind- from the base tube. But the timing and execution must be PERFECT. Getting upright gives us more authority, allowing for greater margin for error. Hanging lower is also compounded by the shape of our control frame- a triangle. The control frame gets wider as it goes down, so hanging lower doesn’t just mean hanging lower, it also means you are reaching more outward to the sides- again effectively shortening your arms. When it comes time to flare in a single suspension harness, you have less available arm extension… not a problem if you land well, but certainly less forgiving.
Not exactly caused by having a single suspension point, but because this type of harness prioritizes low drag over ease of use, SS harnesses fit tightly. In a traditional harness, your body has some room to get more upright than the harness itself. This is most evident in a cocoon, which has no back at all, and one can get their body completely vertical if they wish (being angled slightly forward is actually better, though). However, in a tight-fitting performance harness, your body is held in place much more (which is usually more comfortable in prone-flight, BTW). This means your body is limited in how upright it can be within the harness… and the back-plate-slider arrangement limits how upright the harness can get… so the result is landing in a semi-prone position. Now remember back to when you were taking your lessons, you might recall your instructor advising you to keep your hands about shoulder-level when flying upright? This is because it is generally the best compromise between control and flare potential. Hands lower will let you pull in for speed better, but will not let you flare as well. Hands higher than shoulder height SERIOUSLY compromises control, and actually takes away flare authority as well- because you must begin to straighten your arms to raise your hands up higher… and straighter arms means less extension available when you need it. Hanging in a semi-prone angle means “shoulder height” is now lower on the control frame than if you were more upright… and remember what we learned above about hanging lower in the control frame being a two-fold, compound problem? Again, this doesn’t mean it’s not possible to land- or land well even- it’s just why single suspension harnesses are less forgiving.
Hanging semi-prone also puts the uprights more even with your shoulders, making it more difficult to pull in and keep your airspeed up through your approach. It can be done, but due to the limitations of the human shoulder, it is awkward and takes much practice to be effective. For this reason many pilots flying single suspension harnesses choose to fly their approach from the base tube, transitioning late in the ground skim when near trim, and just before flare. This is less forgiving than getting upright very early, but a choice that some feel more comfortable with due to the more difficult nature of pulling in while on the uprights with a SS harness.
There are also lesser-important issues that come into play, like the added frame or back plate usually makes the harness heavier, and increased wingloading increases stall speed- and the inertia you are trying to stop when landing!
All of these things combine and make single suspension harnesses less forgiving when it comes time to land. It is my own personal assessment that the performance gain is minimal when compared to the sacrifices in forgiveness (IE safety margin). Also, when it comes to XC I personally find the ease of landing my cocoon harness gives me opens up a lot more landing options that I wouldn’t be as safe (or at the very least as comfortable) in a single suspension harness. But these are personal choices that everyone can make for themselves.
And when making that choice for yourself Cal, the answer to which is best or the least compromise- for you- will depend on you more than the brand or model of harness. Everyone’s body is shaped differently, and we all move and fly a little differently, too. What might fit ME well, restrict MY shoulders the least, and generally be the least landing compromise for ME… might heavily impact your body type or flying style. There isn’t a single suspension harness that comes without sacrifices… but which one is best really depends on you.
Best of luck in your search if you decide to pursue a single suspension harness. Try on many, spend lots of time basement-flying them hanging from your rafters, practice the transition and flying upright as much as practical at altitude, before needing to actually land the thing. Basically, embrace the 6P rule.
Proper Preparation Prevents Piss Poor Performance.