KNIK RIVER, Alaska – Unlike other places where speed may dominate pilot discussions, up here it’s all about how slow you can go. It’s directly related to how quickly you can get off the ground and how little room you need to land.
It’s called STOL, or “short take-off and landing,” and here in Alaska it is synonymous with flying.
This weekend pilots from throughout Alaska and across North America will converge on the coastal town of Valdez for the annual Fly-In & Air Show. The big event is Saturday’s STOL competition.A typical pilot in a small single-engine airplane might use 1,000 or 1,500 feet to land on a paved runway, bush pilots often need just a few hundred feet. Sometimes less, because most of the time bush pilots aren’t landing on a runway or anything resembling one.
At the STOL competition in Valdez, takeoffs and landings are measured in tens of feet. Pilots pull up to a line and try to get off the ground with as little ground roll as possible. They also try to touch down as soon as they pass a line on the ground in the shortest possible distance.
OK, where’s the wire?
I’m not going to read the comments cause this seems pretty easy to figure out… The plane was facing into high winds.
I repeat: I am no expert, just giving my first impressions like everyone else here. My first impression: gee those tires sure are “big”–about 2-3X the size of a standard tire used for hard runways so whatever the center of gravity was before those tires were put on, its been raised by 4-5 inches. then yes, the CG has been lowered by whatever additional weight those tires bright to the equation. I’m assuming a net rise to the CG because they are very tall compared to the normal tire but the airplane is not the same ratio more heavy.
Again, probably just my ignorance, but the longetudinal axis of an aircraft has nothing to do with where the CG is. Yes, aircraft are marked where the CG is in an aircraft for purposes of loading it but thats all it is–a reference point for loading–its not “where” the CG is at all. CG does fall within the length, width, and height of an aircraft and ideally for stability it is most often found between the wing chord a few inched down from the wing–usually a few feet behind and above the pilots head.
Ain’t that the shits?
Ha, ha. Rereading my most excellent post, I see I made an error. I was thinking of where the CG was in relationship to the ground==not more properly where the CG was in relationship to the aircraft. Shows what happens when you don’t think about a subject for awhile.
so, recalculating, the CG has been raised with relationship to the ground but its been……I think lowered with respect to its location within the aircraft==the CG being determined only by weight in such calculations.
Yea, I think thats it. Lowered by .002 inches. With the additional drag caused by those tires, the bigger issue is probably the torque created around the center of momentum–typically easily controlled by trim tabs.
Did I just here a large rush of something being blown out of somewhere?
From a physics standpoint, Center of Gravity (CG) is in fact calculated in three dimensions.
Aviation is usually only concerned with longitudinal CG, though there are a number of tactical aircraft where lateral CG can become an issue. A case can be made for instances where vertical matters as well (eg. slope landings in helicopters)
Tundra tires are very large and draggy, but not very dense. They are huge but have a very low PSI to help them absorb impact and “keep them from digging in” as mentioned. I’d be curious to know if Newton ( weight and CG) or Navier-Stokes (aerodynamics) is a bigger influence on performance and handling qualities with tundra tires installed.
Regardless, can we agree to be amazed at both the mad pilot skillz and practical engineering that go into this? What an awesome way to keep the bills paid…
Just keeping it on a roll here, STOL or otherwise, and consistent with a constant theme of mine: there are no mad pilot skills demonstrated here. Its all airplane design and head wind. Nothing even tricky in the approach–wide open and clear. Skills could involve a crosswind over obstacles–but then people could die trying.
What one human can do, pretty much, many other humans can do as well. On the really tricky stuff: practice, practice, practice. And then other humans can do it too if they practice, practice, practice.
Bobbo,
There you go again, painting turds on someone’s rainbows. Though it is quite democratic of you to imply that *any* skill can be learned by *anyone* with practice.
Come back to me when you can bat .350 in the majors and land a helicopter in a small LZ at night.
You also clearly are no pilot, or you would know enough to STFU. Some things are damn hard no matter how much you practice.
Les==thank you for highlighting my democratic value system. And you are quite right==landing a stol aircraft in a stol manner in perfect stol conditions is no where near as difficult as batting 350 in the majors.
Glad to see we are all on the same rainbow.
Looks plausible.
Christ, Bobbo… I actually feel sorry for you. Play along with me, I flew Navy helicopters for 21 years. In practical flying terms, CG is like the pivot point on a teeter-totter. If you put the fat kid up front, the aircraft will nose down. If you put him too far aft, you’ll pitch up and drag your tail rotor. So, If the knuckleheads on a carrier deck are trying to push 10 pallets into my cabin, I want the heaviest to be right under the center of the rotor disk and then the next heaviest right next to it and so on to balance the load. Get it?
Looks (and sounds by the wind) very straight forward to me.
With enough wind, you don’t need forward speed as any 60’s VW driver can attest.