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Part 2 of my RV-7A Aerobatics Lesson

T

TheHDPilot

Member
The second half of my acro lesson doing Loops, Immelmans, and Spins

http://www.thehdpilot.com/aviation-video.aspx?id=81

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TheHDPilot.com
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Another nice video Gene. Just curious - what was behind the recommendation to use right rudder in the initial pull into the loops? Unless your airplane has yaw trim issues, there's no reason to apply right rudder. If it was meant to correct the dragged left wing on the way up, that's best fixed by correcting your pull such that you pull straight back without inadvertently applying aileron.

Regarding that spin recovery technique, I assume he had you keeping the stick back so that you would not unintentionally bring the stick forward before you applied opposite recovery rudder, which could accelerate the spin. Your airplane seems to recover OK with rudder only, but not all airplanes are happy to do that. Standard (and more efficient) spin recovery would be to first apply opposite rudder and then immediately follow with moving the stick forward to around neutral. Good things to discuss on the ground with your instructor so you understand the reasons for the techniques you're using in the air.
 
TheHDPilot said:
Thanks Eddie! Hopefully others will watch it and think... "Hey, I should get some lessons. I'd definitely screw up less than That guy" ;)
/Gene
Click to expand...

I'm with you on that, I try to get time with an instructor to critique my maneuvers on a regular basis and find it a real confidence builder.

Cheers
 
sandifer said:
Another nice video Gene. Just curious - what was behind the recommendation to use right rudder in the initial pull into the loops? Unless your airplane has yaw trim issues, there's no reason to apply right rudder. If it was meant to correct the dragged left wing on the way up, that's best fixed by correcting your pull such that you pull straight back without inadvertently applying aileron.

Regarding that spin recovery technique, I assume he had you keeping the stick back so that you would not unintentionally bring the stick forward before you applied opposite recovery rudder, which could accelerate the spin. Your airplane seems to recover OK with rudder only, but not all airplanes are happy to do that. Standard (and more efficient) spin recovery would be to first apply opposite rudder and then immediately follow with moving the stick forward to around neutral. Good things to discuss on the ground with your instructor so you understand the reasons for the techniques you're using in the air.
Click to expand...

Hi Eric,

What are your thoughts on holding full back stick while applying opposite rudder until the spin stops and then moving the stick forward and initiating recovery?

I was told that doing this helps to stop blanketing the rudder during the spin and allows for faster recovery ?

Cheers
 
eddieseve said:
What are your thoughts on holding full back stick while applying opposite rudder until the spin stops and then moving the stick forward and initiating recovery?

I was told that doing this helps to stop blanketing the rudder during the spin and allows for faster recovery?
Click to expand...

Eddie, airplanes vary, but I've never flown one that recovered a spin more quickly with the stick held back than by moving it forward to a degree immediately after applying opposite rudder. Some airplanes won't recover at all unless the stick is brought forward. The Yak 52 is one of these. Most aerobatic airplanes will recover with rudder alone, but more slowly than using the standard PARE method that moves the stick forward.

It's true that at high angles of attack, aft stick would blank less of the rudder, but typical spin recovery involves both opposing the yaw and reducing AOA. Both aid in stopping a spin efficiently. So when you move the stick forward during spin recovery, you are reducing AOA. The lower your AOA, the less the rudder is blanked by the elevator due to airflow being more aligned with the fuselage. Reduced AOA makes the rudder more effective in opposing yaw. The reduced AOA and opposite rudder combine forces to effect the most efficient spin recovery.

The fastest spin recovery I've ever experienced in any airplane was actually in my old RV-3 after accelerating the spin by moving the stick forward to around neutral and waiting for the rotation to stabilize at its max rate. I then pushed opposite rudder and the spin immediately stopped like hitting a brick wall. NOTE: I'm not advocating for a new spin recovery technique here. I never tried that in other RVs. Heck, it never even occurred to me to try in the Pitts until now. Not much use for this sort of thing in competition. :)
 
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Eric,
I have always used right rudder on the loop entry due to P-factor.
Even some left on the backside.
Are you saying that is incorrect?
 
MarkW said:
Eric,
I have always used right rudder on the loop entry due to P-factor.
Even some left on the backside.
Are you saying that is incorrect?
Click to expand...

Mark, I'd not call that incorrect if your particular airplane (and how you fly it) requires that, and gives you proper results. At typical loop entry speeds in the various airplanes I've flown, I've never noticed a need for right rudder until the over-the-top section where you'll notice some slipstream yaw due to the low airspeed.

When you pitch into a loop, yes there is slight P-factor, but there is also a little gyroscopic precession (in right turning engines) that applies a right yawing force. This is stronger with metal props, of course. This tends to cancel any need for right rudder during the pull into a loop. Some high power-to-weight airplanes running metal props may actually need a touch of left rudder pressure when pitching hard into a loop. And in high-powered airplanes with light composite props, I've never noticed a need for right rudder, but airplanes vary, and your experience may be different. For most pilots, the need for right rudder during loop entry means they are correcting a dragged wing condition due to inadvertently applying a touch of left aileron during the pull. This is very common.

But you also mention left rudder on the backside. I assume this is because you're pulling power off on the backside? At high speed, and low power settings, many airplanes require some left rudder to trim the airplane regardless of any maneuvering. But if you maintain a high power setting throughout the loop, you likely will not need that, but again that is my experience, and your airplane and experience may be different.

I notice lots of folks pulling large amounts of power off (even to idle) on the backside of loops for fear of overspeeding and blowing out low. This is not necessary, and will not lead to nice looking loops. As long as you exit the loop at just about the same altitude as you entered, it's physically impossible to gain airspeed during the loop if your power setting is constant. Don't pull power, just manage your G so that you end up about the same altitude as you entered. Of course, be ready to pull power if you mess it up a little.
 
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sandifer said:
Another nice video Gene. Just curious - what was behind the recommendation to use right rudder in the initial pull into the loops? Unless your airplane has yaw trim issues, there's no reason to apply right rudder. If it was meant to correct the dragged left wing on the way up, that's best fixed by correcting your pull such that you pull straight back without inadvertently applying aileron.

Regarding that spin recovery technique, I assume he had you keeping the stick back so that you would not unintentionally bring the stick forward before you applied opposite recovery rudder, which could accelerate the spin. Your airplane seems to recover OK with rudder only, but not all airplanes are happy to do that. Standard (and more efficient) spin recovery would be to first apply opposite rudder and then immediately follow with moving the stick forward to around neutral. Good things to discuss on the ground with your instructor so you understand the reasons for the techniques you're using in the air.
Click to expand...

Eric,
I see MarkW already replied with same thing i was going to say, P-Factor. If i don't feed in a little right rudder the left wing lags the right wing on the way up. I just assumed that it was the same principle as when climbing out on a take-off. No?

Spin / Stick Back... Yes, I guess I was letting the stick come (too far) forward before completely stopping the spin with the rudder. I realize that is the right way for me to be doing it, but i guess i was so hot and tired by that point and had lost my focus.

That brings me to a question on spins that i've had in the back of my head. For an Intentional spin, the stick is already all the way back because that's the way you force the spin to happen. But what about an UN-Intentional spin, say at the top of a loop or trying to do an Immelman? There, the stick probably won't be all the way back when the spin occurs (i'm guessing). So is the right technique to immediately bring the stick fully back until you stop any rotation that might be occurring by using the rudder, and then let the stick come forward to break the stall?

Gene
 
sandifer said:
I notice lots of folks pulling large amounts of power off (even to idle) on the backside of loops for fear of overspeeding and blowing out low. This is not necessary, and will not lead to nice looking loops. As long as you exit the loop at just about the same altitude as you entered, it's physically impossible to gain airspeed during the loop if your power setting is constant. Don't pull power, just manage your G so that you end up about the same altitude as you entered. Of course, be ready to pull power if you mess it up a little.
Click to expand...

Thanks for the explanation on this Eric! I don't know where I'd picked up on the idea of pulling power out on the down side, but you can even hear my instructor telling me to leave it in (when I asked why the AOA was chirping). It's reassuring to hear you confirming that he's correct.

Gene
 
TheHDPilot said:
I see MarkW already replied with same thing i was going to say, P-Factor. If i don't feed in a little right rudder the left wing lags the right wing on the way up. I just assumed that it was the same principle as when climbing out on a take-off. No?
Click to expand...

Gene, the effect exists, but is much less pronounced at the high airspeeds of a loop entry compared to a Vx or Vy climbout. But there are lots of variables, which is why I'm not saying there is only one technique needed. Airspeed entries vary, pitch rates (gyro precession) vary, prop/HP combinations vary, etc. But for most people, these dragged wing conditions are caused by improper stick movement rather than rudder movement. First make sure you're pulling the stick perfectly straight back. And then if rudder is needed, use whatever it takes.

TheHDPilot said:
That brings me to a question on spins that i've had in the back of my head. For an Intentional spin, the stick is already all the way back because that's the way you force the spin to happen. But what about an UN-Intentional spin, say at the top of a loop or trying to do an Immelman? There, the stick probably won't be all the way back when the spin occurs (i'm guessing). So is the right technique to immediately bring the stick fully back until you stop any rotation that might be occurring by using the rudder, and then let the stick come forward to break the stall?
Click to expand...

It's hard to spin most airplanes unless the elevator AND rudder are nearly fully deflected...and held. You just don't do that while doing loops and rolls. That's not to say you can't snap out of figures, but a spin will generally only develop if you maintain near full deflection of both controls. The example of stalling on top of a loop will just lead to slight pitch and roll bobbles if you're coordinated, and a dropped wing if you're not. Try it next time you fly with Adam - try pulling the stick all the way back on top and see what happens. The airplane will protest, but you're not likely to actually spin.

Similar deal on top of an Immelman - if you get too slow and mishandle the elevator and rudder a little, you can snap out of the top. This is not uncommon. But this is really a stall/snap rather than a spin entry. Neutralizing the controls will immediately bring the aircraft back under control. It's very hard to get into trouble in any aerobatic airplane if you neutralize the rudder and elevator as soon as the airplane snaps, departs, stalls, etc. You don't need to go into spin recovery mode until you actually see a spin developing. You'll learn the difference between spin entries and simply snapping or stalling out of maneuvers. All pilots learning acro should gain experience with this.
 
sandifer said:
Gene, the effect exists, but is much less pronounced at the high airspeeds of a loop entry compared to a Vx or Vy climbout .... First make sure you're pulling the stick perfectly straight back. And then if rudder is needed, use whatever it takes.

It's hard to spin most airplanes unless the elevator AND rudder are nearly fully deflected...and held. You just don't do that while doing loops and rolls ....
Try it next time you fly with Adam - try pulling the stick all the way back on top and see what happens. The airplane will protest, but you're not likely to actually spin. Similar deal on top of an Immelman...
Click to expand...

Good points that I will try Eric. 1st, i will make sure the stick comes Straight back. I can easily imagine that i'm not being accurate enough there. 2nd, i will ask Adam if we can try hauling the stick back at the top of a loop. It's best i see what can happen under controlled conditions.

One follow-up question... Remember that guy who was very concerned that other RV guys would try to do Immelmans after watching me do them and end up in spins? Given your description of what would happen (most likely falling off rather than ImmelSpinning), can you explain what his concerns might have been?

Gene
 
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You were really hard on yourself ! Of course the instructor is there to help you improve but don't feel so intimidated. You must have 180 hp cause you pull through the verticals much better than I do. But I'm learning from these videos that you are pulling a lot more than me. I keep my loops to around 2.5 gs which for my power isn't enough pull I think. Great video. I wish I could get instruction in my 6a and be in the aerobatic category.
 
TheHDPilot said:
One follow-up question... Remember that guy who was very concerned that other RV guys would try to do Immelmans after watching me do them and end up in spins? Given your description of what would happen (most likely falling off rather than ImmelSpinning), can you explain what his concerns might have been?
Click to expand...

Gene, I had to go back and look, but he didn't explain his position in much detail and didn't respond to further discussion. The Immelman happens to be a maneuver that ends with low airspeed. If you mishandle the maneuver, you can snap out on top. Snapping is more likely than spinning with this one. I don't think it's too important to worry about whether it's a stall w/ wing drop, snap, or spin as you depart controlled flight. None of it is a big deal. Pilots flying solo aerobatics should be able to recover any type of loss of control.
 
Thanks Eric,
I will pay more attention to rudder input during loops.

Just a note on the throttle during the backside of the loop.
My biggest fear of performing a loop in the RV was an overspeed on the backside. I feared that to control the speed I would need to pull excessive G's or allow an Vne.
Now I fly the loop with full throttle all the way around to keep my speed up/the same. Fears were baseless.
Thanks.
 
erikpmort said:
You were really hard on yourself ! Of course the instructor is there to help you improve but don't feel so intimidated. You must have 180 hp cause you pull through the verticals much better than I do. But I'm learning from these videos that you are pulling a lot more than me. I keep my loops to around 2.5 gs which for my power isn't enough pull I think. Great video. I wish I could get instruction in my 6a and be in the aerobatic category.
Click to expand...

Erik, I was most disappointed i guess by feeling like i'd been improving toward my goal of doing solo acro and this flight kind of felt like i'd take a little step backward rather than forward. I'm going to blame the heat for throwing me off that day ;)
I have an AeroSport Power O-360-A1A. When new it was rated at 200 hp. Now, with 1100 hrs on it i'm figuring that it's not quite that high anymore. I was a bit surprised though to see climb rates pulling up into the loop of 6000'/min.
I'm no expert, by a looooong shot, but loops feel best when i hit between 3.0 and 3.5 G going into them. Maybe Eric S can give us his opinion on what we should shot for, or if it even really matters all that much.

Gene
 
MarkW said:
Thanks Eric,
I will pay more attention to rudder input during loops.

Just a note on the throttle during the backside of the loop.
My biggest fear of performing a loop in the RV was an overspeed on the backside. I feared that to control the speed I would need to pull excessive G's or allow an Vne.
Now I fly the loop with full throttle all the way around to keep my speed up/the same. Fears were baseless.
Thanks.
Click to expand...

Now that I realize everyone is saying that keeping power in all the way around is what i should have been doing all along, i'm definitely going to start doing them that way myself. Thanks for the feedback Mark.

Gene
 
TheHDPilot said:
I'm no expert, by a looooong shot, but loops feel best when i hit between 3.0 and 3.5 G going into them. Maybe Eric S can give us his opinion on what we should shot for, or if it even really matters all that much.
Click to expand...

Gene - for fun flying, you can pull whatever G you like, and whatever gets you over the top. Doesn't matter. If you're interested in doing actual round loops (or close to), 3-3.5G won't work since such a soft pull will produce an initial radius so large that the RV won't be able to maintain enough energy over the top to keep the radius constant (round). Low G loops look like a cursive letter 'L' from the ground. Ron or Bill could tell us exactly what they pull in the RV, but it will likely be more like ~4.5G for a round loop. To fly round loops, pilots must also adjust to much more time spent floating over the top. When coaching new pilots from the ground with round loops, you're pretty much saying, "Pull harder...now float it, float it...not enough float!!". :)
 
Gs and loops

Eric is about right on the initial positive Gs being about 4.5 and between 0.5 and zero Gs at the top for the way I fly a competition loop in my RV-4. When I do an inverted loop, I only push negative 3 Gs and try to get most of the rotation at the top to minimize the negative Gs at the bottom. It definitely looks like a small case "L", but that's not for competition. On use of the rudder in a loop, I'm really not aware of what my feet are doing, but what I see, so I am putting in some rudder at the top to prevent yaw. When I do a hammerhead, which is initially a 1/4 loop, I'll progressively add right rudder on the vertical up line to keep the left wing from dropping or dragging. Aerobatics are fun, and trying to make them "perfect" is even more challenging and FUN.:D
Bill McLean
RV-4 slider
lower AL
 
WillyEyeBall said:
Eric is about right on the initial positive Gs being about 4.5 and between 0.5 and zero Gs at the top for the way I fly a competition loop in my RV-4. When I do an inverted loop, I only push negative 3 Gs and try to get most of the rotation at the top to minimize the negative Gs at the bottom. It definitely looks like a small case "L", but that's not for competition. On use of the rudder in a loop, I'm really not aware of what my feet are doing, but what I see, so I am putting in some rudder at the top to prevent yaw. When I do a hammerhead, which is initially a 1/4 loop, I'll progressively add right rudder on the vertical up line to keep the left wing from dropping or dragging. Aerobatics are fun, and trying to make them "perfect" is even more challenging and FUN.:D
Bill McLean
RV-4 slider
lower AL
Click to expand...

Good Info Bill! The few times i got 'carried away' and pulled back at 4G I was told i didn't have to hit it so hard. 4.5G for loops, that would take some getting use to.
I'm dumbfounded to think my loops, despite feeling like a circle, are really looking like that lower case script 'L'. It would really be nice to have a way to see what all my maneuvers look like from the 3rd party perspective. But doing things up at 4000'+ AGL would require a really long lens for a ground photographer.
 
My Favorite

sandifer said:
Pilots flying solo aerobatics should be able to recover any type of loss of control.
Click to expand...

Was kind of lurking and watching this thread develop, its nice to see a thread run out that doesn't leave me scratching my head.

I especially like the quoted line, above. When one can botch a maneuver and recover with an inner monologue around the line of "whoopsie!", as opposed to dread and uncertainty they are most likely ready to continue exploring the envelope solo. I usually swear...another reason not to invest in the audio cable for the GoPro.
 
Gene,
The only way I have found to get a good view of your loop is to compete.
I thought mine were round until I got some coaching while in the box.
The primary routine is very easy and a blast to fly in competition. All the guys are great and will help. Find a IAC chapter in your area.
They also have a rule that will let you compete with an instructor aboard during competition. (no passengers though)
Our local chapter even has a practice weekend almost every month where they open the box at the airport. Good way to get critiquing on you flight from a pro on the ground using a radio to straighten it out right now.
And the RV loop is best above 4g's.
 
Pull power on the back side of a loop?

Eric and Bill are right: loops are not going to be round if your initial pull is less than 3.5 G and I like 4 to 4.5.

There is no reason to pull power on the back side of the loop as Eric has pointed out. Properly flown you will come out of the loop at the entry altitude with slightly less airspeed while maintaining full power.

I maintain firewall power throughout the entire Sportsman routine except when slowing for the spin entry. A loss of energy (kinetic + potential) in one maneuver means there is less energy to start the next one. This results in a routine that loses altitude. I doubt that any RV has the power to gain altitude during a typical aerobatic routine so pulling power at any point is just adding to the problem. I typically start my routines at 2500 feet and end up about 800 feet lower after 10 or 12 maneuvers. I am working on a 6-figure Sportsman free sequence. Each figure is more complex than those in the known sequence so they eat up more altitude. The end result is still about a 800 foot loss of altitude.



Thanks to Eric Sandifer for helping me develop this sequence. (Eric, I ditched the 4-point on the rev half Cuban exit in favor of a 1 1/2 roll with an inverted sequence finish. Figured if I'm going against the tide with a downwind entry I may as well finish unconventionally as well.) I don't expect to win with this sequence. I want to show what the RV is really capable of doing. Kinda like Bill's inverted spin.
 
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