12 Seconds to Pattern Altitude

Jay Honeck

Jay Honeck

Touchdown! Greaser!
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Jay Honeck
As many of you know, we've recently transitioned to the Van's RV-8A, an aerobatic, tandem seat, 2-place high performance homebuilt. To say this is about as far away from our Cessna/Piper/Beech/Ercoupe spam-can flying as can be wouldn't be too much of an exaggeration.

We've put 51 hours on it, in just six weeks. This includes ten hours (5 apiece) of pretty intensive transition training. Both of us can pretty much thread the needle with "Amelia", now, after so much in-cockpit time.

Back to those 12 seconds. Many would argue that the most vulnerable time in-flight is the departure phase. High power, high angle of attack, low speed, long climb. Lose your engine there, and things often end badly.

Which is why I wanted to share an unexpected advantage of sport planes in general, and the RV-8 specifically -- enhanced safety during the climb out phase. So little time is spent in this critical phase of flight (as compared to most GA planes) that your odds of an engine failure during that phase are dramatically reduced.

Here's my departure procedure in the -8A, illustrating what I mean:

Full power, breaking ground in less than 500 feet.

Keep the nose down, flying in ground effect, letting the speed build until there is no more usable runway ahead. This will put me right at 140 knots indicated, at our 3600' long island airport's runway.

A firm-but-not-crazy pull will have me at pattern altitude in just 12 seconds! This is a 5000 FPM climb, with two people, full fuel, on a 90+ degree day.

I can't imagine what it would be like solo, light on fuel, on a cold Iowa day! :D

In addition to being great fun (obviously!), it is comforting to know that our exposure to that most critical phase of flight is so small.

So there you have it. Enhanced safety. Yet another reason to fly an RV!
:D
 
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At the end of the runway if the fan stops with no place to land ahead. Can you make 180 and land safely ?
By the way I love your plane !
Have fun .
 
Concorde said:
At the end of the runway if the fan stops with no place to land ahead. Can you make 180 and land safely ?
By the way I love your plane !
Have fun .
Click to expand...

Well, in theory, I've got 140+ knots to convert to altitude by then.

Landing straight ahead at that speed would be unwise, so my procedure would be the same, but with the caveat that if I can't make it to 600' AGL, I would ditch in the shallow water just off the beach, more or less straight ahead.

Why 600'? Because in my transition training, I learned that I need 500' to make a 180 degree turn, power off.
 
Tried that in the -10 at gross. Off in 1000'. 120 kts at the end of 5000'. Did not time the climb but pretty sure I would be in trouble without a field somewhere directly ahead if my engine quit at the numbers. Try pulling the mixture at a safe altitude while simulating a turning climb from the virtual "end of rwy". My airspeed decays rapidly. I think my safest bet is climbing out at 100-105 kts. Wear your safety goggles for that little bird that WILL penetrate your windshield.

This guy likes to fly low and fast...

http://www.vansairforce.com/community/showthread.php?t=77750

Here are some bird strike pics...

http://m1074.photobucket.com/albums/rv6aaviator/
 
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Jay Honeck said:
Well, in theory, I've got 140+ knots to convert to altitude by then.

Landing straight ahead at that speed would be unwise, so my procedure would be the same, but with the caveat that if I can't make it to 600' AGL, I would ditch in the shallow water just off the beach, more or less straight ahead.

Why 600'? Because in my transition training, I learned that I need 500' to make a 180 degree turn, power off.
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Thank you Sir !
 
Jay Honeck said:
Well, in theory, I've got 140+ knots to convert to altitude by then.

Landing straight ahead at that speed would be unwise, so my procedure would be the same, but with the caveat that if I can't make it to 600' AGL, I would ditch in the shallow water just off the beach, more or less straight ahead.

Why 600'? Because in my transition training, I learned that I need 500' to make a 180 degree turn, power off.
Click to expand...

The physics says you can't convert the 140 kts kinetic energy to the needed AGL:

Ekinetic = mairplane*V2/2
Epotential = mairplane*g*h

Ekinetic = Epotential
mairplane*V2/2 = mairplane*g*h
V2/2 = g*h
h = V2/(2*g)

So:
g = 32.2 ft/s2
V = 140 kts = 236 ft/s
h = 2362/64.4 = 865 ft

You'd be stationary at 865 ft above your starting height. You'd want to be flying at least at stall speed at the end of the "zoom," so available V for an RV-8 would be about 90 kts (152 ft/s). Computation of h in this case is left as a simple exercise for the reader.

Since no loss of energy to air friction was taken into account, and you're changing velocity vector using a fluid, conservation of momentum means not all that kinetic energy can go into your airplane climb. Some of the available kinetic energy has to go into moving air so conservation of momentum is satisfied.

However, it may be worth trying an experiment at altitude where you are flying straight and level at 140 kts, cut the power to idle and pull back on the stick. Note the altitude gained when the speed reaches stall speed. Remember to level out and apply power - any lower speed gets into aerobatic territory.

I suspect you may be getting fooled by the power to weight ratio into thinking the RV-8 is capable of more than it is when the engine is no longer running. The great climb isn't due as much to lateral kinetic energy as it is to simply having a relatively powerful engine.
 
Jay Honeck said:
Why 600'? Because in my transition training, I learned that I need 500' to make a 180 degree turn, power off.
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Be careful with assumptions like that. You need more than 180 degrees to land on something beneath you, and entry speed (entry energy) will effect how much altitude that turn takes.

I think that if the engine were to fail you'd be in a better position having flown Vy, having altitude and being near your best glide speed, than you would be flying low and fast and then having to zoom climb. But I could be wrong, and that definitely doesn't sound as fun. :D


Sent from my Nexus 7 using Tapatalk 4
 
bqmassey said:
Be careful with assumptions like that. You need more than 180 degrees to land on something beneath you, and entry speed (entry energy) will effect how much altitude that turn takes.

I think that if the engine were to fail you'd be in a better position having flown Vy, having altitude and being near your best glide speed, than you would be flying low and fast and then having to zoom climb. But I could be wrong, and that definitely doesn't sound as fun. :D


Sent from my Nexus 7 using Tapatalk 4
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I can assure you that is the case. Every time I've had a pilot try to tell me that staying low and putting on a little airshow is safer I have them demonstrate that versus climbing out at the appropriate airspeed and they're always better off doing that. The faster you go down low, the more energy you lose to drag that you could have out into altitude had you just climbed at the appropriate airspeed.
 
There's a reason Vy is Vy.

A zoom climb is only at Vy for a fraction of a second. Before you slow to Vy you're pulling and sloughing energy at a higher rate.

Slower than Vy you aren't climbing as well as you could and it's about time to switch to best glide and go down anyway if the dinosaur-driven flour mill has stopped.

This is dumb, Jay. Fly the numbers. Seriously.
 
Mary and I just hashed this out over dinner.

With the scenario that the engine quit just as I ran out of usable runway, while holding the nose down and going 140 knots, my 600' target altitude (for a power off zoom climb, turn back and landing) is too optimistic. As someone pointed out, it's going to take MORE than a 180-degree turn to get back to the runway -- probably more like 240 degrees -- which shoots my target estimate all to hell, even with the 100' pad I had built in.

The target should be more like 900' AGL, but reality dictates that during those first few "oh, crap" moments you're not going to be thinking analytically enough to do this sort of math, nor would you pull up instantly.

More likely, you would do a gradual pull to Vy, and glide to a water landing just offshore, which was my Plan B all along.

But back to the goal, which is to minimize your time spent climbing out. This is the critical phase of flight where an engine failure can do you the most harm, so the least amount of time spent grinding uphill, the better.

I still contend that a zoom climb to pattern altitude puts you in that danger zone for less time than grinding it out at best rate. Of course, I am assuming that a runway landing is possible during the first half of my low altitude speed run, should the engine quit. This is problematic, but certainly no more so than an engine failure at, say, 300' AGL.

As Mary pointed out, the only way to say for sure is to try it both ways, and time the climb from the "point of no return" to the "point of safe turn back".

This sounds like a valid excuse to fly... :D
 
(And, frankly, the zoom to altitude is so danged much fun that I doubt I would stop doing it, even if the numbers don't show any safety enhancement...)
:D
 
There is value to accelerating to Vy in ground effect at a high density altitude airport, out but not past it. That shouldn't be an issue in an RV 8 anyway because the acceleration is so quick.

I am also in the camp that immediate altitude is your friend. Once you hit Vy, climb out.
 
Jay Honeck said:
(And, frankly, the zoom to altitude is so danged much fun that I doubt I would stop doing it, even if the numbers don't show any safety enhancement...)
:D
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Practice the maneuver at higher altitude first. You could inadvertently put the plane into an accelerated stall at low altitude, ruining your whole day.

Edit: And try to avoid yanking the wings off.
 
Yeah, it is fun. From a safety standpoint Vy is better. On longer runways you could likely make an argument for Vx, as you could (past a certain runway length) put yourself in a position where you would always be able to make the runway, either strait ahead or by turning back.
 
Jim Logajan said:
Practice the maneuver at higher altitude first. You could inadvertently put the plane into an accelerated stall at low altitude, ruining your whole day.

Edit: And try to avoid yanking the wings off.
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ha.....

Someone needs to tell Bob Hoover not to try to return to the runway when the engine(s) quit....;):D
 
A CFI years ago was talking with me about engine failures on the climb out, right after takeoff. We were having a theoretical discussion, but I did try it at altitude.

During the climb you are at a high angle of attack. If your engine quits, you now lose most of your upward vertical vector. That leaves you moving forward at an even higher angle of attack and closer to a stall.

Since I don't have the luxury of a plane like yours (yet), I can't really do a zoom climb like that. Have you tried, at altitude, to 'fail' your engine during that climb to see how your upward momentum affects your entry into a stall? Your plane probably will continue to climb ballistically for plenty of time to get that stick forward. I'm curious how much time there really is?
 
N801BH said:
ha.....

Someone needs to tell Bob Hoover not to try to return to the runway when the engine(s) quit....;):D
Click to expand...

I'm sure Jay knows that when I say he ain't no Bob Hoover I mean him zero disrespect!
 
Jay Honeck said:
....and the RV-8 specifically -- enhanced safety during the climb out phase. So little time is spent in this critical phase of flight (as compared to most GA planes) that your odds of an engine failure during that phase are dramatically reduced.

Here's my departure procedure in the -8A, illustrating what I mean:

Full power, breaking ground in less than 500 feet.

Keep the nose down, flying in ground effect, letting the speed build until there is no more usable runway ahead. This will put me right at 140 knots indicated, at our 3600' long island airport's runway.
Click to expand...
What a bunch of poppycock.

If you actually do the study, and do hair pin reversals, you will end up so much farther from the runway using a Vy ground effect zoom climb, than if you simply climbed at Vx.

......this mental infestation eventually leads to Dagger Flight antics. It's a PISTON SINGLE, for heaven's sake. And there are others with similar power to weight ratios.....
 
Jay Honeck said:
Mary and I just hashed this out over dinner.

But back to the goal, which is to minimize your time spent climbing out. This is the critical phase of flight where an engine failure can do you the most harm, so the least amount of time spent grinding uphill, the better.

:D
Click to expand...

The goal is to minimize the amount of time you are exposed without enough runway in front of you or available energy (altitude + speed) to RTB safely. With a CS prop, VY is the way to go. With a fixed pitch prop, the ideal climb speed is arguably higher to enable the engine to turn a higher RPM so you build energy faster and <again> minimize the time you spend in the exposure zone.
 
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Jay Honeck said:
Mary and I just hashed this out over dinner.

With the scenario that the engine quit just as I ran out of usable runway, while holding the nose down and going 140 knots, my 600' target altitude (for a power off zoom climb, turn back and landing) is too optimistic. As someone pointed out, it's going to take MORE than a 180-degree turn to get back to the runway -- probably more like 240 degrees -- which shoots my target estimate all to hell, even with the 100' pad I had built in.

The target should be more like 900' AGL, but reality dictates that during those first few "oh, crap" moments you're not going to be thinking analytically enough to do this sort of math, nor would you pull up instantly.

More likely, you would do a gradual pull to Vy, and glide to a water landing just offshore, which was my Plan B all along.

But back to the goal, which is to minimize your time spent climbing out. This is the critical phase of flight where an engine failure can do you the most harm, so the least amount of time spent grinding uphill, the better.

I still contend that a zoom climb to pattern altitude puts you in that danger zone for less time than grinding it out at best rate. Of course, I am assuming that a runway landing is possible during the first half of my low altitude speed run, should the engine quit. This is problematic, but certainly no more so than an engine failure at, say, 300' AGL.

As Mary pointed out, the only way to say for sure is to try it both ways, and time the climb from the "point of no return" to the "point of safe turn back".

This sounds like a valid excuse to fly... :D
Click to expand...

Whatever you need to tell yourself to justify your actions.
 
Jim Logajan said:
Practice the maneuver at higher altitude first. You could inadvertently put the plane into an accelerated stall at low altitude, ruining your whole day.

Edit: And try to avoid yanking the wings off.
Click to expand...

That's that whole "firm-but-not-crazy pull" part.
 
bbchien said:
What a abunch of poppycock.

If you actually do the study, and do hair pin reversals, you will end up so much farther from the runway using a Vy ground effect zoom climb, than if you simply climbed at Vx.
Click to expand...

Although I would naturally end up farther down range, I believe I would also have more altitude to work with in order to get back to the runway.

I'm sure there is a mathematical way to test this, but it's beyond my high school algebra. I sure wish we still had the Kiwi flight simulator set up -- it would be a simple test to make.
 
bartmc said:
5000 FPM? Wonder why the FAA hasn't recommended this technique as a best practice? :mad2:
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Hmmmmmm.........

First, the FAA hates Experimentals as we can "explore" all the neat stuff you certified guys will have to wait 30+ years to enjoy..


Second... The FAA does NOT recommend any flight profiles for experimentals..


And third.... I flew as a safety pilot for my hangar buddy with his RV-6 after he installed the Dynon synthetic vision with A/P.... Absolutely AMAZING....

Try installing that in your Bonanza.. :no::nonod::no: ............;)
 
Jay Honeck said:
Although I would naturally end up farther down range, I believe I would also have more altitude to work with in order to get back to the runway.
Click to expand...

Altitude isn't the issue. Energy is, and in this case energy = Kinetic (speed) plus Potential (altitude).

At 140 knots and very low altitude, I suspect the math would show you'd be better off to do a quick, high bank angle 225 degree turn ( probably 4 G's), then a 45 back to the runway than to convert your speed to altitude, then maneuver back to the runway.

Why? Gravity. Every second you're powerless, gravity is accelerating you in the wrong direction at 32 ft/sec ^2. Minimize the exposure time to this energy drain and you'll have more energy for something productive, like returning to the airfield.

This approach requires you to be proficient in high G, low altitude turns..
 
Jay Honeck said:
Although I would naturally end up farther down range, I believe I would also have more altitude to work with in order to get back to the runway.

I'm sure there is a mathematical way to test this, but it's beyond my high school algebra. I sure wish we still had the Kiwi flight simulator set up -- it would be a simple test to make.
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Do it for real, Jay. You'll never zoom climb again.

You waste so much mV2 energy getting airspeed in ground effect, and overcoming drag, when you could have been banking it with altitude.

Yeah you may get to turnback ALTITUDE in 12 seconds. But you won't have Vy +5 to make the 45 degree banked turn (which is just barely above g-load stall). So, you'll make a big turn and not make it back.

You've been infected with "fighter pilot" syndrome. Get a grip. You'll actually have to put the nose down and travel AWAY from the airport long enough to accomplish Vy+5 to make the tight turn. Remember, 45 degrees is 1.414 x the stall speed of S&Level.

Sorry to POP your bubble. But it is JUST a bubble.
If I didn't know you better I'd be thinking you'll be in a flightsuit next....
 
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bbchien said:
Do it for real, Jay. You'll never zoom climb again.

You waste so much mV2 energy getting airspeed in ground effect, and overcoming drag, when you could have been banking it with altitude.

Yeah you may get to turnback ALTITUDE in 12 seconds. But you won't have Vy +5 to make the 45 degree banked turn (which is just barely above g-load stall). So, you'll make a big turn and not make it back.

You've been infected with "fighter pilot" syndrome. Get a grip. You'll actually have to put the nose down and travel AWAY from the airport long enough to accomplish Vy+5 to make the tight turn. Remember, 45 degrees is 1.414 x the stall speed of S&Level.

Sorry to POP your bubble. But it is JUST a bubble.
If I didn't know you better I'd be thinking you'll be in a flightsuit next....
Click to expand...

I'm not so sure about that. When we level off at pattern altitude, I am still at 100 knots plus. That's certainly well above Vy. Hmmm... :idea:

Since I doubt I will be practicing any knife-edge turns back to the runway, it's more of a mental exercise than anything, and (of course) the zoom climb is great fun to do. If it were dangerous in any way, trust me, Mary would be thwacking me in the back of the head all the way uphill. :lol:

As for flight suits, Mary and I actually have some. We used to wear them like overalls over our clothes while working on the plane in Iowa, to keep clean and warm. Never flew with them, though.

Down here on the island, it's too hot for those things! :)
 
If it is such a great idea to stay in ground effect while building up far more speed than needed to start a climb, why don't airliners do it?

High speed close to the ground is fine for air show performers, who have accepted the extra risk. For the rest of us, altitude is our friend.
 
Geez guys/gals.................

There is not ONE of use reading this thread that has not done a zoom climb................... and we are all still alive...:yes:;)


Give Jay a break...;)
 
NoHeat said:
If it is such a great idea to stay in ground effect while building up far more speed than needed to start a climb, why don't airliners do it?

High speed close to the ground is fine for air show performers, who have accepted the extra risk. For the rest of us, altitude is our friend.
Click to expand...

Airline pilots have to make sure the passengers don't scream. :lol:

As an exercise, if it takes 35 seconds to get to a safe turnback altitude by climbing out "normally", but takes only 25 seconds to get to a safe turnback altitude utilizing a zoom climb, doesn't it make more sense to reduce your time at risk by ten seconds?

(The numbers are all approximations, BTW. I only measured the time from the end of the runway to pattern altitude, not the time from brake release.)
 
N801BH said:
Geez guys/gals.................

There is not ONE of use reading this thread that has not done a zoom climb................... and we are all still alive...:yes:;)


Give Jay a break...;)
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No, because Jay is wrong. He is so far downrange with his technique....and he needs to go out and demonstrate it to himself. Heck I can go out and develop 800 points for Vyse Stop vs. go, he can do six hairpin reversals from which he'll see the error.

If he was really concerned about TIME as an exposure window, he would climb at Vy which by definition is the most efficient configuration for the conversion of climb into altitude. If he was a fighter pilot, he COULD climb a Vx(95%), which is the slower airspeed which produces 95% of Vy's steady state ROC, not lose much and be closer to the runway.

But in fact, he's a GA guy and would be really lucky in a clutch, to make the 45 degree bank angle turn, into the crosswind, not stall and die, and get it back down. Adding arrival at an airspeed NOF comfortably above 1.414 x stall then becomes another task- because you want to make the turn as SMALL as possible.

Not don't be saying "unload the wings". That's yet ANOTHER cognitive task.

Oh heck. Just wear the flightsuit. I'll try to contain my laughter on the flightline.
 
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Jay Honeck said:
I'm not so sure about that. When we level off at pattern altitude, I am still at 100 knots plus. That's certainly well above Vy. Hmmm... :idea:! :)
Click to expand...

Go up to 3,000' and practice all of the alternatives, pretending that your runway elevation is 3,000'.

Start at 60 knots (your takeoff speed), accelerate to 140 knots, pull the power, and try the zoom approach and the tight horizontal turn approach. Measure the length of time during each maneuver that you couldn't safely RTB (for instance, beyond 100 knots, maybe you don't have enough runway to land straight ahead, so that's when the timer starts.). The timer stops when you've got the energy to complete the RTB maneuver. I'd guess that any energy state where you have 120+ knots (and any altitude) or more or 100 knots and 500' is doable.

Try the same thing using a Vy climb. I suspect your exposure will be shorter.
 
Your exposure is from lift off to pattern altitude, not from when you haul back into the zoom. Make two departures, Vy and zoom, and time from rotation to TPA. I'd bet your zoom climb is longer. Time both to low-level cruise, say 3500 feet, too, just for fun.

Impossible Turn practice should include at least a 2-second delay before you do anything, to simulate recognizing the problem and choosing an appropriate action. Nose down to Best Glide, 45 degree bank into the wind. Do this at a safe altitude over straight shoreline, road, power lines, etc., to see how far you went sideways while turning, correct back, then see how much altitude you lost. It'll be more than 500 feet.

However it works out, do the tests safely. Your nice new plane deserves to be treated well. And you deserve to fly her proudly for years to come.
 
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