Whilst sitting in the shade of a tent to keep the sun off in the 35° heat alongside the grass runway and not moving too far away from the cooler boxes filled with water bottles, and watching the 100hp Ikarus tow gliders into the air 3 things crossed mind.
1/ How did such a low powered aircraft manage to tow even the 2 seater wooden gliders into the air?
2/ Are there any metal gliders?
3/ Why does everyone, pilots and passengers don a parachute before entering the aircraft?
This is not the first time I’ve wondered about when one might use a parachute.
Now I don’t want to get into the usual debate about the Cirrus. The CAPs system makes perfect sense to me especially when flying at night or IFR.
I first started wondering a few weeks ago when starting out in the club ULM. It is normally equipped with a ballistic parachute, like most ULMs round here. But on this occasion it was out for its regular maintenance and hadn’t come back yet. Should I be worried? I decided not as when I fly SEP I I usually don’t have one, anyway.
The parachute returned by the time of my next flight and as per check list I dutifully pulled the pin, and stowed it safely. I then went off to practice landings and take offs using around 100m to 150m. It got me wondering, when might I use the parachute. In most areas there is usually a field, road, car park, back garden where there is 100/150 metres to put down if the engine fails. So it would have to be some sort of structural damage, as I wouldn’t be flying a ULM at night or in IMC especially as there is no AI.
But in a glider there is no engine to fail and here on this beautiful day the guys were putting there aircraft down with precision on what appeared to be the length of my deckchair and rolling to a halt exactly where they wanted.
So why a personal parachute? And if the answer is structural damage caused by a mid air collision or airframe fatigue, would you be able to get out to use the chute?
I look forward to the glider experts on here educating me.
No glider expert, but I believe that it’s because gliders tend to congregate close together (as opposed to powered aircraft pilots who strive to be as far away from other aircraft as possible, within reason) and so the risk, or perceived risk, of a mid-air collision is high.
I believe they have a good chance of getting out when it does happen, e.g. here https://www.gov.uk/aaib-reports/5-2010-g-byxr-and-g-ckht-14-june-2009
Mid-Air collisions in gliders are very common, I know someone who had two and he bailed twice (he never did parachutes before)
I think wearing parachute makes sense, the same for aerobatics with risk of structural failures
I don’t see mid-air collision or airframe stress being an issue in the typical IFR tourers, the CAPS seems more useful for incapacitated pilot or engine failure secnarios
Mid-air in Cirrus while under IFR would be a very rare event unless you fly in front of a MetroLiner
2/ Are there any metal gliders?
I used to fly Pilatus B4 glider, it’s metal structure
- It acts like mix of harmonica & guitar when it comes to noise from airflow
- You are likely to break your neck before the glider breaks
- It sucks in thermal for cross-country and if you land out in a field you will notice that you don’t much friends as you think
Ibra wrote:
Mid-Air collisions in gliders are very common,
To elaborate on Ibra’s answer, that’s because several gliders tend to use good thermals at the same time. That’s also one of the features of the FLARM system. It is designed to predict flight paths to avoid spurious alarms in situations where gliders fly close together. FLARM displays even have a special symbol for circling gliders.
gallois wrote:
So why a personal parachute? And if the answer is structural damage caused by a mid air collision or airframe fatigue, would you be able to get out to use the chute?
Yes. It happens all the time, collisions that is, and parachutes have proven to save lives. In an accident just a few years ago, a glider got into IMC. The pilot bailed out, but too late. A few seconds earlier and he would have survived.
We also use parachutes when flying aerobatics. In theory that works, but I’m not all too sure in practice. Some planes are very hard to jump out from. Small doors, cramped. IMO, only planes with a “glider configuration cockpit/canopy” really works.
ULs all have chutes, BRS. IMO a better solution than parachutes. When to use it? That’s the question. An engine failure over dense woods and other unlandable surfaces is one, flying into IMC is another. And of course structural failure. What people don’t often think about is that they can also be used to “land” on very small surfaces. A few feet above touch down, pull the cord, and it will act as a brake shute.
gallois wrote:
1/ How did such a low powered aircraft manage to tow even the 2 seater wooden gliders into the air?
The aerodynamic quality of gliders is just so much better than of the flying GA bricks. It all comes down to lift/drag. I’ve dabbled a bit in the respective math, I could elaborate if you’re interested.
Inkognito wrote:
The aerodynamic quality of gliders is just so much better than of the flying GA bricks. It all comes down to lift/drag. I’ve dabbled a bit in the respective math, I could elaborate if you’re interested.
This video shows how low the forces really are. Back of the envelope suggests 400kg glider with 30:1 lift/drag is only about 130N of drag. Obviously a bit more when accelerating but really there’s not much drag force at all.
LeSving wrote:
ULs all have chutes, BRS. IMO a better solution than parachutes.
I’d agree on that. There is one scenario though, where I’d rather have an emergency chute on my back: fire/smoke in the cockpit at higher altitude.
I always wear an emergency chute when flying my Europa. That makes sense in my opinion as it’s easy to get out from the upright seating position through the gullwing doors of the Europa, which will depart the airplane as soon as opened in flight. My chutes also have an automatic activation with the static line connected to the aircraft structure, which has proven to be a lot better especially for non parachutists/passengers in the stress situation of an emergency bailout.
That’s some skill without the use of throttle/brake 
europaxs wrote:
There is one scenario though, where I’d rather have an emergency chute on my back: fire/smoke in the cockpit at higher altitude.
True.
