Tips and tricks thread

[cargocowboy]

That's a flight school thing. Best angle of climb doesn't really exist in an operational world.

It sounds like it should.

maintain the free energy of ground effect as long as possible

How would one tell what "as long as possible" is?

but the gist of the original treetop comment is,

Actually that's not how I interpret the gist of the treetop comment at all. I interpret it as, if you're not sure if you can clear the trees, don't panic and haul back on the yoke. If you're going to hit them, do so under positive control, instead of stalling it in. Or maybe the gist is just that climb performance falls off rapidly if you get too slow, and that's easier than it sounds when in a corner. But the ambiguity is why I asked for more explanation.

But if you can "aim at the top of the trees" and still clear them by 10 feet flying at 100 knots, then you wouldn't be in any danger of hitting them at all, at any sensible airspeed - maybe 60 is too slow, but 70, 80, or 90 wouldn't be. So I don't know how it helps.

Maybe I misunderstood. Watch a loaded beaver on floats take off. Watch a Pawnee with a full hopper take off. Take 3 of your friends in your 172 and take off on a high DA day. If you fly published Vx, you're going to have a bad time.

[2112]

Tree tops are much softer than they look and it's apparently safer if badly cornered on take off, to go through it
(Up to some point of course) Instead of above and stall.
The actual tip would be not to put yourself in such a position.

Isn't it the best thing to do to climb at your best-angle-of-climb speed, and ignore the trees altogether?

Because a CPL in general, and especially a bush pilot, will go through great lengths to come up with alternative procedures to avoid having to admit something he learned from a flight instructor actually made sense.

Because a CPL in general, and especially a flight instructor, will go through great lengths to come up with alternative procedures to avoid having to admit something he learned from a bush pilot/line pilot actually made sense.

Bit of a two way street on this one, I've seen some sketchy shit from both sides of this argument.

Follow your sop's, keep an open mind, trust but verify.

[digits_]

Tree tops are much softer than they look and it's apparently safer if badly cornered on take off, to go through it
(Up to some point of course) Instead of above and stall.
The actual tip would be not to put yourself in such a position.

Isn't it the best thing to do to climb at your best-angle-of-climb speed, and ignore the trees altogether?

That's a flight school thing. Best angle of climb doesn't really exist in an operational world. That's an argument unto itself, but the gist of the original treetop comment is, maintain the free energy of ground effect as long as possible and have excess airspeed when skimming those treetops. Far safer than pitching up and riding the stall speed while clawing for altitude over said trees.

The 'free energy' is eating up your limited distance that you have available before you reach the trees.

If this technique works to clear the trees, then it wasn't required in the first place.

[digits_]

If you fly published Vx, you're going to have a bad time.

Why? The Vx published, depending on the manual, takes quite a few factors into account.

Obviously don't use a Vx at sea level for a take off at 5000 ft and 35 C.

[cargocowboy]

It's the internet, and it's my opinion. Take it or leave it. Or better yet, try it out for yourself.

Suggest you read "Stick and Rudder" by Wolfgang Langewiesche, and "Contact Flying" by Jim Dulin.

[photofly]

The 'free energy' is eating up your limited distance that you have available before you reach the trees.

If this technique works to clear the trees, then it wasn't required in the first place.

So we've veered a bit off the "simply don't stall into the trees" and deep into "accelerate in ground effect then zoom-climb over the trees" territory, but let's throw some numbers at it. Compare climbing at a steady 70 knots vs accelerating in ground effect to 100 knots then zooming up until you've slowed to 70.

The zoom-climb gets you about 230 feet of altitude, as steep as you like - it's just a ballistic climb. But the downside is you have to eat up distance accelerating from 70 to 100, without climbing at all. Contrasting a regular climb at 70 knots that gives you 500fpm rate of climb, that 230 feet would have taken you 28 seconds, and eaten up 3300 feet of distance.

So if you can accelerate from 70 to 100 (in ground effect) in better than 3300 feet then a zoom-climb gets you to 230' faster than a steady climb at 70. Can you do that? I couldn't say.

More generally it's a problem similar to this one, albeit with very different numbers, if anyone recognizes this graph:

Screen Shot 2022-02-06 at 11.05.19 PM.png (752.09 KiB) Viewed 1380 times

[TG]

The 'free energy' is eating up your limited distance that you have available before you reach the trees.

If this technique works to clear the trees, then it wasn't required in the first place.

So we've veered a bit off the "simply don't stall into the trees" and deep into "accelerate in ground effect then zoom-climb over the trees" territory, but let's throw some numbers at it. Compare climbing at a steady 70 knots vs accelerating in ground effect to 100 knots then zooming up until you've slowed to 70.

The zoom-climb gets you about 230 feet of altitude, as steep as you like - it's just a ballistic climb. But the downside is you have to eat up distance accelerating from 70 to 100, without climbing at all. Contrasting a regular climb at 70 knots that gives you 500fpm rate of climb, that 230 feet would have taken you 28 seconds, and eaten up 3300 feet of distance.

So if you can accelerate from 70 to 100 (in ground effect) in better than 3300 feet then a zoom-climb gets you to 230' faster than a steady climb at 70. Can you do that? I couldn't say.

More generally it's a problem similar to this one, albeit with very different numbers, if anyone recognizes this graph:

Screen Shot 2022-02-06 at 11.05.19 PM.png

Sorry, I think my initial comment was lost in translation.
Nobody would deliberately take off overloaded in a warm summer day from a short strip/lake with the idea of aiming at treetops to go through them to make it!
It's just a counter intuitive option to keep in mind if you get badly cornered and realize you won't make it anyway without hitting them.


In that case yes, release your yoke and let your wheels or floats touch the treetops. That won't be the end of the world and you'll get a much better outcome than pulling in a fear of touching them. Which is exactly what most green CPL out of school would do (Yes, I know they are not supposed to put themselves in this kind of scenario, nobody is)


Disclaimer: I never ended up in this position and I do not recommend ending up in this position
It's bush flying, a few times you have to say no to a trip, a few times you think it's going to be tight for all sorts of reasons but you do it and most of the time it's a none event.



Too bad Hedley/the Colonel and Cat Driver are gone from this forum, they would have a few tricks to pass on I'm sure.
Speaking of Cat, one of his best saying: "The hardest thing about flying is knowing when to say no"

[PilotDAR]

release your yoke and let your wheels or floats touch the treetops. That won't be the end of the world and you'll get a much better outcome than pulling in a fear of touching them.

As a last resort, having put yourself in a bad situation to begin with, I agree with this. I would rather pull a leaf out of a gear leg, than stall into the trees. How many videos have we seen of an airplane mushing off the surface, wings no loner level, and colliding with the surface. The report said "failed to achieve/maintain flying speed". The airplane which landed at the destination maintained flying speed.

Vx is a valid speed to climb at, I've done the testing. If you really need to clear an obstacle, and there is no margin, you should fly at Vx. However, while flying slower than Vy, you have put yourself in a very vulnerable phase of flight if the engine stops. The notion of "popping up" over trees at the last second, well.... not no, but not the best idea either. If a steady climb at Vx or faster will get you safely over the obstacle, do that. If a steady climb at Vx will not get you over the obstacle, you should have had a plan more practiced than something you just read on AvCanada.....

[TG]

you should have had a plan more practiced than something you just read on AvCanada.....

No kidding...

Which make me think that this covid sub-forum is a total embarrassment
But that's another topic.