help with lazy eights

[GSMPilot]

so i'm working through this commercial ticket and need some help with those lazy 8's, any advice from you CFI's would be greatly appreciated, right now i'm just doing them in a c-172, nothing special, i just want to get the basic idea of it down, but everytime i do it, i'm either too fast or too high from my inital altitude. any ideas?

Thanks,

Keith

[jrh]

It's been a while since I've done lazy 8's, but if you either end up too high, or at the correct altitude but too fast (because you were going to be too high so you forced it down to altitude, therefore gaining airspeed), that means you initiated the maneuver with too much power.

Think of it this way--if you pull the power to idle and do a lazy 8, you will end too low (duh, obviously, you're just gliding), and if you go to full power, you are going to end up too high, because climbs are the result of excess thrust, and full power will mean you have excess thrust. You have to find the perfect power setting in the middle that puts you out where you want to be at the end.

Also, remember that the outside temperature affect the amount of power required. That means that manifold pressure will need to change based on the weather...a little higher MP in the summer, a little lower MP in the winter. I've never thought about this for a 172 before, but it has manifold pressure too--just no gauge for it and no way to precisely set it. But you get the idea...more throttle in the summer and less throttle in the winter.

Good luck with your flying...I found commercial training to not necessarily be the hardest, but definately the most frustrating training.

[Chris_Ford]

[ QUOTE ]
so i'm working through this commercial ticket and need some help with those lazy 8's, any advice from you CFI's would be greatly appreciated, right now i'm just doing them in a c-172, nothing special, i just want to get the basic idea of it down, but everytime i do it, i'm either too fast or too high from my inital altitude. any ideas?

Thanks,

Keith

[/ QUOTE ]

So I started writing this nice long explanation for 8s on pylons

If you're continually too fast or too high, you might want to try knocking 100 RPM down or so. Also, when you get to the peak points (when you're at your 45' point), I always suggest a quick glance down at the attitude indicator, so you know how many degrees down you have to pitch. For example, if at the 45 degree point, you're 2 bars up, then at the 135 degree point, you should (briefly) be 2 bars down.

It's a tough maneuver and it takes some practice, so don't worry too much about it, just keep working on it and try to learn where your mistakes are being made. That, to me, is a better indication of ability, when someone can say "Well I ended up high because I had too much power in," or, "I didn't pitch down enough". If you understand how the maneuver works, flying it will become easier.

[roundout]

theoretically, you shouldn't have to adjust the power at all. if you fly the maneuver correctly from start to finish, you should end up at the same airspeed and altitude you began at. how likely is it that you will fly perfectly or won't get bumped around by summer thermals? doubtful at best, but i advocate correcting errors with the yoke and rudder first. the power is the last thing i change in trying to make a lazy-eight acceptable. i know quite a few people who fly lazy eights with one hand on the trim wheel and only rudder input to steer the plane. there's nothign that says you can't. i've even been known to try this to really emphasize the intended laziness of the maneuver.

[kellwolf]

What pitch attitude are you getting to at the peak points? I did my CSEL and my CFI-A in a 172, and the thing I always did was not pitching up enough to get slow enough at the peak points. If you don't slow down enough, you wind up too fast, and if you try to force the plane through the manuever, you might accidentally level it out at some point, which would cause you to be too high.

From what I've heard, it's easier to do in an Arrow since the plane wants to slice through the air anyway. The 172 just wants to keep flying. Done power off 180s in a 172 yet? They take forever. Might as well just fly a regular pattern.

[jrh]

How can you account for my example of doing a lazy 8 at idle power or at full power then? They won't work out.

I'm not saying you're wrong, I just don't understand how you can say power doesn't matter. I think part of the commercial manuevers is learning how to use power appropriately to complete a maneuver. I don't think you should be jockeying with the throttle at all once the maneuver is started, but you have to set the power correctly to begin with.

[kellwolf]

I never touch the throttle on lazy eights. Get the plane below Va, stabilize the airspeed and altitude, then execute the maneuver. To me, it's one more thing that can cause the maneuver to go wrong.

[project7]

What helped me a lot was to think of the 45 and 135 degree positions as the max pitch up/down points. You need to bleed off the speed faster than you'd think, so getting the nose to a nice high pitch angle right away helps. I never worried about the change in altitude, it varies (as hot as it's been lately in socal, I sometimes get only 100 ft). If you focus on performing the pitch and bank changes correctly, then all the other factors should work out for you.

[KLB]

Don't play with the power do the right at manuevering speed. You probably know the procedure. I'll just explain how I do them and how I teach them.

1. Climbing turn
2. At 45 degree point, you should be at 15 degrees bank and max pitch
3....... Continuing turn ......at 90 degree point you should be at 30 degrees of bank and the nose should be falling through the horizon.
4. At 135 you should be rolling out through 15 degrees bank, max pitch down and starting your back pressure to get back level with the horizon.

Remember it takes a good bit of right rudder pressure to counteract the left turning tendencies when going to the right.

That works pretty good for me. And like said earlier.....the manuever will not go perfect on hot and bumpy days. You are always going to have to make adustments throughout the manuever.

Good Luck.

[ricecakecm]

When I was flight instructing, we did commercial maneuvers in 172's and 172RG's. The power setting and airspeed were key to getting things to work out. In the 172, we'd use 1800 RPM and around 90 knots. In the RG, 18 inches and 95 knots. The maneuver was designed to be done around 90 knots or so. If you do it at Va (100ish in most planes this is done in), you'll be way too fast and have problems with airspeed at the 135 degree point.

Also, I would make students keep their hand off the throttle. When I flew them, I flew with 2 hands to help keep them smooth and also give me more precise control. I also gripped the pad in the center of the yoke, not the handles, this helped with over-controlling.

Keep the maneuver lazy and slow. If you try to rush it, things won't work out. Just keep practicing and you'll eventually get the hang of it.

Good luck!

Chris

[Chris_Ford]

[ QUOTE ]
theoretically, you shouldn't have to adjust the power at all. if you fly the maneuver correctly from start to finish, you should end up at the same airspeed and altitude you began at. how likely is it that you will fly perfectly or won't get bumped around by summer thermals? doubtful at best, but i advocate correcting errors with the yoke and rudder first. the power is the last thing i change in trying to make a lazy-eight acceptable. i know quite a few people who fly lazy eights with one hand on the trim wheel and only rudder input to steer the plane. there's nothign that says you can't. i've even been known to try this to really emphasize the intended laziness of the maneuver.

[/ QUOTE ]

When I said "adjust the power" I meant... "You know that power setting you usually enter the maneuver in? Bump it down 100 RPM" ...

Sorry for not being clearer.

[MikeD]

[ QUOTE ]
How can you account for my example of doing a lazy 8 at idle power or at full power then? They won't work out.

I'm not saying you're wrong, I just don't understand how you can say power doesn't matter. I think part of the commercial manuevers is learning how to use power appropriately to complete a maneuver. I don't think you should be jockeying with the throttle at all once the maneuver is started, but you have to set the power correctly to begin with.

[/ QUOTE ]

Power doesn't matter in the sense of once your power is set, it shouldn't need to be touched. Correcting with power defeats the intent of the precision of the maneuver.

[jrh]

[ QUOTE ]
[ QUOTE ]
How can you account for my example of doing a lazy 8 at idle power or at full power then? They won't work out.

I'm not saying you're wrong, I just don't understand how you can say power doesn't matter. I think part of the commercial manuevers is learning how to use power appropriately to complete a maneuver. I don't think you should be jockeying with the throttle at all once the maneuver is started, but you have to set the power correctly to begin with.

[/ QUOTE ]

Power doesn't matter in the sense of once your power is set, it shouldn't need to be touched. Correcting with power defeats the intent of the precision of the maneuver.

[/ QUOTE ]

That's been my point all along! But finding the right entry power setting is important to the maneuver. Once the maneuver is started, power shouldn't be touched. But if your entry power setting is too high, you'll end the maneuver either too high or with too much airspeed, and if your initial power setting is too low, you'll end up low and/or slow.

From reading roundout's reply, I got the impression that he was saying any power setting would work if you got the pitch and roll inputs correct. I don't think that it works that way. Did I misunderstand something somewhere along the line?

[MikeD]

[ QUOTE ]
That's been my point all along! But finding the right entry power setting is important to the maneuver. Once the maneuver is started, power shouldn't be touched. But if your entry power setting is too high, you'll end the maneuver either too high or with too much airspeed, and if your initial power setting is too low, you'll end up low and/or slow.

[/ QUOTE ]

Not necessarily. If your power setting is too high, and you do everything correct, you'll simply have a larger-sized "8" (ie- higher altitude gain to apex). Everything else should remain the same. Similiarly, if you did it with too low a power setting, you'd have a very small "8" that will be descending. Cruise power setting should work fine.

[ QUOTE ]

From reading roundout's reply, I got the impression that he was saying any power setting would work if you got the pitch and roll inputs correct. I don't think that it works that way. Did I misunderstand something somewhere along the line?

[/ QUOTE ]

Any power setting within reason, partner. Of course you're not going to do them at idle, unless you want a descending 8, which isn't the intent. But they can be done fine in a 172 at 1800, 2000, 2200, or full power.....all with varying sizes of figure "8s"

In that respect, power doesn't matter.

[jrh]

Man, I feel like a goof. After re-reading this thread, I finally figured out what was going on. We've all been saying the same thing, using different words. Disregard my previous posts...

[MikeD]

[ QUOTE ]
Man, I feel like a goof. After re-reading this thread, I finally figured out what was going on. We've all been saying the same thing, using different words. Disregard my previous posts...

[/ QUOTE ]

It's all good. Chalk it up to internet explanations. If this had been getting explained to you face to face, I'm sure it would've been more clear.

It's all good!

[MidlifeFlyer]

[ QUOTE ]
What helped me a lot was to think of the 45 and 135 degree positions as the max pitch up/down points.

[/ QUOTE ]It got lost in the power discussion but I think this is a big key. The most common error I see is doing the maneuver too quickly. I had a commercial student who had done aerobatic training and was having a lot of difficulty slowing down his Lazy 8s to the commercial type.

The key for him was to divide the maneuver into 45° segments (all =visually= of course!). Each has a specific pitch and bank target.. It allows you to "catch up" and make any necessary corrections 8 times in the course of the maneuver rather than waiting for the 180 or 360 points.

45º – ½ bank, max pitch up
90º – max, level pitch
135º – ½ bank, max pitch down
180º – straight and level

[GSMPilot]

okay after reading all this valuable info guys, i think i'm doing the manuver with too much power and too high an airspeed, so come friday we'll see it that is the issue. Thanks alot for the helps guys, always dependable on this site. If it doesn't work out on friday i'll come back with more feedback and see what else i'm doing wrong.

[ndbhater]

You should also note that the "max pitch down" is not nearly as extreme as "max pitch up". I teach my students that 5 degrees nose down is usually enough. Any more than that can lead to excessive airspeed. Power setting should not make any difference. As Mike D said, it will only change the size of your eights.

[jrh]

[ QUOTE ]
You should also note that the "max pitch down" is not nearly as extreme as "max pitch up". I teach my students that 5 degrees nose down is usually enough. Any more than that can lead to excessive airspeed. Power setting should not make any difference. As Mike D said, it will only change the size of your eights.

[/ QUOTE ]

I believe the pitch down attitude should be identical to the pitch up attitude. According to the Airplane Flying Handbook, top left of page 6-19, the airplane should be flown in a "descending turn so that the airplane's nose describes the same size loop below the horizon as it did above."

Although this doesn't specifically say, "Pitch down the same number of degrees as was pitched up," I think that is the intent. I don't see how it could be done otherwise.

And heck, while I have the AFH cracked open, I might as well quote the FAA on what we all talked about in our power discussion:

"The correct power setting for the lazy eight is that which will maintain the altitude for the maximum and minimum airspeeds used during the climbs and descents of the eight. Obviously, if excess power were used, the airplane would have gained altitude when the maneuver is completed, if insufficient power were used, altitude would have been lost."

I don't know why nobody (myself included) thought to reference the AFH sooner during this discussion.

[FOD]

I think alot of students have trouble with the words "level flight attitude", "max pitch down", etc.. Its doesnt give them a visual on what this looks like. I must admit that I even have trouble explaining that. Can anyone here give a good description...thanks

[MidlifeFlyer]

[ QUOTE ]
I think a lot of students have trouble with the words "level flight attitude", "max pitch down", etc.. Its doesn't give them a visual on what this looks like. I must admit that I even have trouble explaining that.

[/ QUOTE ]I don't understand what you are saying. You get in an airplane, take off, gain altitude, set up a cruise speed, establish level flight, and look out the window. What you see is "level pitch attitude" for you, in that airplane, with the seat set at that height.

If a commercial applicant doesn't know what a level pitch attitude looks like, he needs to go back to primary training (actually, he probably used to know what it was before instrument training destroyed it).

[Snapadeuce]

Good posts on a difficult maneuver. I would like to add a couple of things.

1. Don't think of the maneuver in mechanical terms; don't sweat your pitch/bank at the key points. Your first few tries will stink; as you continue, you will 'feel' the maneuver and the altitudes and airspeeds will be there for you.

2. Start the maneuver perpendicular to the wind. Each half of the maneuver will then be into the wind and the control forces will feel similar to you.

[project7]

[ QUOTE ]
In the 172, we'd use 1800 RPM and around 90 knots.

[/ QUOTE ]

The 172 (at least the 1979 "N" model) has an entry speed to the lazy 8 and chandelle stated in the AFM as 105 KIAS. I usually started the lazy 8 at 22-2300 RPM and 105 KTS.

[sopdan]

[ QUOTE ]


The 172 (at least the 1979 "N" model) has an entry speed to the lazy 8 and chandelle stated in the AFM as 105 KIAS.

[/ QUOTE ]

Grr, I come in late to a discussion and have something to share, only to find the last post says exactly what I was going to say. 105 kts is also for the R model, and I've found that to work great everytime. In fact, Lazy-8s are probably one of my best maneuvers. Keep it smooth, plan, coordinate, blah, blah, blah, look out the window!!!