81–90 of 183 posts
The report of the investigation: https://turvallisuustutkinta.fi/material/attachments/otkes/t...
It's amazing how much work they've put into creating this quite unique configuration just to find out the stall behaviour.
It seems his takeoff technique was adequate for thousands of takeoffs until a gust hit at the wrong time and place and yanked the rug out from under him.
Earlier quoted context omitted.
Stall speed depends on so many factors that it can change significantly in a single flight. Weight, altitude, density altitude, angle of attack etc. are all going to have an effect. In other words, sure, you might want to confirm it, but you should also give yourself some margin since you don’t ever really know what the stall speed is until you stall.
How do you determine a margin without some form of a baseline?
In a certified aircraft the manufacturer has already done the test flying
It is not necessary to empirically determine a specific airplane's stall speed in order to operate it safely. It's not required in the US, we just use the number the manufacturer publishes. It's normal for airplanes of the same model to fly differently: I fly a little fleet of six Citabrias, and their stall characteristics are radically different. You'd expect more uniformity from a modern aluminum airplane, but stil…
Decreases the stall speed? How does that work?
https://ciechanow.ski/airfoil/
Useful to think of the airplane as standing still while the engine accelerates the air around it. To fly, you need the air to move over the wings quickly and in the right direction.
You can sort of trade how fast you need the air to go for how ideally the air is flowing over the wings. If you angle the wings just right against the air flow, and/or you bend them out of shape just right with flaps, you can slow down a lot while relying on the air itself to carry your plane. If you're flying against the airflow, you need to go faster.
This is usually done during take off and landing. The pilot lowers the flaps when approaching to land and flares the aircraft before touchdown, all to make the air flow efficiently into the wings, thereby allowing the aircraft to slow down without falling straight down like a stone.
That's why weather is so important for flights. Pilots need to be ready to call TOGA and go maximum thrust at a moment's notice just in case some crosswind or heat wave or something screws up the direction of the air flow just as they're about to land. Many an admiral cloudberg article has been written due to that sort of thing. You angle the plane just right, slow it down just to the edge of stalling, then some phenomenon happens and increases your stall speed past your current speed...
Earlier quoted context omitted.
Stall speed depends on so many factors that it can change significantly in a single flight. Weight, altitude, density altitude, angle of attack etc. are all going to have an effect. In other words, sure, you might want to confirm it, but you should also give yourself some margin since you don’t ever really know what the stall speed is until you stall.
How do you determine a margin without some form of a baseline?
Earlier quoted context omitted.
Stall speed depends on so many factors that it can change significantly in a single flight. Weight, altitude, density altitude, angle of attack etc. are all going to have an effect. In other words, sure, you might want to confirm it, but you should also give yourself some margin since you don’t ever really know what the stall speed is until you stall.
Don't forget ice!
Non sequitur from non-pilot: I was once in Duluth, MN in the bitter cold and watched a Cessna with skis (for landing on the frozen lakes of the Boundary Waters) land at the airport. It was the utterly bewildering to see how slowly it was going in the air. And how little distance it took to stop. Short Landing Kit I assume. I've seen ducks and geese come into land on lakes at higher speeds!
"According to the operating handbook, the An-2 has no stall speed. A note from the pilot's handbook reads: "If the engine quits in instrument conditions or at night, the pilot should pull the control column full aft and keep the wings level. The leading-edge slats will snap out at about 64 km/h (40 mph) and when the airplane slows to a forward speed of about 40 km/h (25 mph), the airplane will sink at about a parachute descent rate until the aircraft hits the ground." As such, pilots of the An-2 have stated that they are capable of flying the aircraft in full control at 48 km/h (30 mph) ... This slow stall speed makes it possible for the aircraft to fly backwards relative to the ground: if the aircraft is pointed into a headwind of roughly 56 km/h (35 mph), it will travel backwards at 8 km/h (5 mph) whilst under full control."
It is not necessary to empirically determine a specific airplane's stall speed in order to operate it safely. It's not required in the US, we just use the number the manufacturer publishes. It's normal for airplanes of the same model to fly differently: I fly a little fleet of six Citabrias, and their stall characteristics are radically different. You'd expect more uniformity from a modern aluminum airplane, but stil…
Citabria's are often flown in aerobatics (Citabria backwards is airbatic and for a while, they were the only aerobatic aircraft being commercially manufactured in the US) and a lot of aerobatic maneuvers involve stalling the wing.
Earlier quoted context omitted.
In my vernacular, I distinguish between "life jackets" and "buoyancy aids". Apparently most people don't. A buoyancy aid has a foam core, and always provides buoyancy. It's the sort of thing you'd wear while kayaking, but it's far too bulky to want to wear it unless you expect to go in the water. A life jacket is inflatable, and normally automatic. If you're at risk of falling in, and to do so would be dangerous, you…
Which vernacular is that? In boating a life jacket does not need to be inflatable. https://uscgboating.org/recreational-boaters/life-jacket-wea... says: > There are four basic design types: Inherent, Inflatable, Hybrid, and Special Purpose. > There are two main classes of PFDs. > * Those which provide face up in-water support to the user regardless of physical conditions (lifejackets). > * Those which require the use…
Isn't the English language fun?
It is not necessary to empirically determine a specific airplane's stall speed in order to operate it safely. It's not required in the US, we just use the number the manufacturer publishes. It's normal for airplanes of the same model to fly differently: I fly a little fleet of six Citabrias, and their stall characteristics are radically different. You'd expect more uniformity from a modern aluminum airplane, but stil…
Decreases the stall speed? How does that work?