“Bulls eye” and a “splash” would be a better description 
Another (minor) point is that parachutes in gliders are constructed/folded so that they double as (relatively comfortable) cushions. There are usually no separate cushion sets available. So even if you go onto a flight where the mid-air collision risk is zero, you’d still wear a parachute. Otherwise you’d be uncomfortable and probably so low in the aircraft that you would not be able to look out.
How much would you trust a parachute in a LSA or ultralight compared to a Cirrus for which there are dozens of successful deployments documented? Few weeks ago this accident where the parachute failed was in the news.
Quote:
In the air, this resulted in the demolition of both wings of the aircraft for reasons that have not yet been clarified. The rescue system in the aircraft was then triggered. However, the parachute, which is supposed to slow down the fall of the plane, was damaged. As a result, the aircraft fell to the ground at increased speed. The 53-year-old pilot suffered fatal injuries from the force of the impact.
FWIW he might have been outside the speed envelope for the parachute deployment.
Clipperstorch wrote:
How much would you trust a parachute in a LSA or ultralight compared to a Cirrus for which there are dozens of successful deployments documented? Few weeks ago this accident where the parachute failed was in the news.
Why would you trust Cirrus more than an LSA or UL, when the rocket / parachute comes from pretty much the same company? In any case, there are recorded instances where a Cirrus had its chute pulled and it failed. In one case, the aircraft was above Vpd and the pilot was fatally injured, the other, the pilot was able to land successfully.
From my side, I do trust all BRS / Parachute systems but only as a last resort and not as a “get out of jail free” card. My planning does not include “I have a chute, I’ll be alright” but rather my thoughts are:
Would I attempt this trip in (eg) a C172 without BRS? If the answer is NO, I won’t go.
Steve6443 wrote:
Why would you trust Cirrus more than an LSA or UL, when the rocket / parachute comes from pretty much the same company?
Good question. I would assume that, since there is quite a bit of money involved in that, there is not a whole lot of testing done for every airframe at least not enough to do proper statistics. In case of the Cirrus there is now enough data available though the testers were mainly the customers/pilots.
Steve6443 wrote:
From my side, I do trust all BRS / Parachute systems but only as a last resort and not as a “get out of jail free” card.
This should of course always be the case. What I thought of was more of a situation where you still have some options (e.g. engine stopped). In a Cirrus you are drilled to pull, whereas in another plane you might be the first to try a BRS installation in a specific airframe.
Clipperstorch wrote:
Good question. I would assume that, since there is quite a bit of money involved in that, there is not a whole lot of testing done for every airframe at least not enough to do proper statistics. In case of the Cirrus there is now enough data available though the testers were mainly the customers/pilots.
What testing needs to be done? In the case of an LSA, they fire off the rocket whilst on the ground and ensure these fixing points are capable of sustaining the stress. I know Cirrus did real life testing but that, if I recall, was because the wanted to show an alternative means of compliance for spin testing; however they still ended up spin testing their aircraft after EASA wanted it done as a precursor to acceptance.
Clipperstorch wrote:
This should of course always be the case. What I thought of was more of a situation where you still have some options (e.g. engine stopped). In a Cirrus you are drilled to pull, whereas in another plane you might be the first to try a BRS installation in a specific airframe.
Funny story – I was training in an LSA with BRS and the instructor said: right, engine failure. So I said: check for any suitable landing spots, as none are in gliding distance, pull the chute. He then pointed out that the aircraft I was in had a 15:1 glide ratio and pointed in the distance to an airstrip. I said: “We won’t reach that”, in response to which he said: “Challenge accepted”, switched off the engine – a Rotax 912iS – and off we went. Needless to say, I now appreciate that the gliding performance of certain LSAs is higher than some certified types….
Steve6443 wrote:
switched off the engine – a Rotax 912iS – and off we went. Needless to say, I now appreciate that the gliding performance of certain LSAs is higher than some certified types….
It certainly helps that with a Rotax the prop actually stops and is not windmilling.
This is at least in one instance been proved to be a misconception:
boscomantico wrote:
This is at least in one instance been proved to be a misconception:
He may be right, but I’m not sure. He measured the sink rate and not the glide ratio. The speed for best glide changes when the drag changes and he flew the same airspeed.
One need the whole polar curve (ASI vs VSI) for both feathered propeller and windmilling propeller, the. compare best L/D on each profile as Vbg will vary slightly…intuitively, the windmilling propeller will create more drag without adding any lift, however, things need to be confirmed by an actual L/D tangent on the polar curve
More puzzling question, does the change of flaps increase best L/D under power OFF? we all know takeoff flaps will help increasing best % climb gradient on takeoff under power ON, will that help for best L/D?
These debates on propellers are irrelevant in real life, the propeller feathering system or governor mechanism is unlikely to work during an engine failure and the effect is dwarfed by wind & weight conditions. Also, one is likely to compare effects on L/D that are bellow instrument position error from flap & propeller on ASI/VSI
In SF25C, the only way to stop the propeller is to bring it near stall first under 50kts where it drops like brick, it start windmilling again at +75kts, air-restart on dead battery needs +90kts
