Spin left ;-)

[ebetancourt]

It seems hard to believe that 2 1/2 years or so have gone by since I first mentioned spins in my Classic Waco. A lot of life stuff went on, and I just haven't had time to work at learning to fly well. But this year...

Anyway, as a refresher, I mentioned that the book says 1700 feet in the first turn. That seems to be pretty accurate, with spins to the right. I have done all spins to the right because that is more comfortable (My new knee was part of that time and it is great). But today everything worked out and I went up to do spins to the left. Almost a different airplane.

I have set myself a goal of doing primary in this airplane, not that I am that big on competition, but as a "syllabus" to force me to fly to a goal. I was worried about fitting in the box losing 1700 in the spin, then going straight down to build speed for the half Cuban. (You did know a Waco did the first Cuban right?)

But the left spin is totally different, and the loss is only about 6-700 feet. I find that weird. I suppose it could be pilot induced, but in all of my spins I use two hands to make sure the stick is centered, and today I looked at the stick in the last spin to make sure. I have full rudder in, and the throttle is at idle. I would like to think the entry is the same, smoothly go to the stop on the rudder as the airplane stalls. In the right spin the airplane points almost straight down (~80*). In the left spin, it goes beyond vertical about 5 -10 degrees. In either direction, it stays level for an instant, and the wings drops to very close to 90* then the nose goes down. I can certainly see why the book says it will move to a spiral dive after three turns. Recovery BTW is essentially instantaneous; center the rudder and it is done. It is easy to over lead and come up short by most of the lead. 5* lead seems plenty.

Anyway, I am committed to putting together the primary this year. In this airplane it will be mostly an energy management exercise. It does a nice loop, and a reasonable aileron roll. I need to get a slow roll into my repertoire and the half Cuban.

This is a lot of fun

 

[Arbiter419]

I don't really have anything to contribute to this thread other than the fact I could watch a big old Waco do acro alllll day long.

This thread needs pics!

 

[whifferdill]

Ernie, first let me say that I love the idea of a Waco at a contest! I've seen some Stearmans, but never a Waco.

I have set myself a goal of doing primary in this airplane, not that I am that big on competition

Don't think of it as a competition with other pilots. Believe it or not, most of us don't think of it that way. It's the personal challenge and camaraderie. The competition is with yourself. You want to be there to have a good time and learn. Make a point of that, and the "competition" will become secondary.

I've got some questions for you - maybe I can help, but mostly I'm just curious. Are you running a wood or metal prop? The three things that make spin characteristics asymmetrical between the left and right are prop torque, prop mass (gyroscopics) and residual propellor slipstream at idle. If you're running a wood prop, torque and gyroscopic effect will be very minimal. And I've only noticed slipstream to have much affect on the initial spin entry. If you have a low idle, and a wood prop, it's hard to imagine the airplane spins so differently left vs. right - especially with respect to altitude loss. 1700' for one turn seems more like T-6 territory!

Back when I was running a metal prop on my Pitts, spin characterstics left and right were very different. Not so much now that I'm running a 12 lb. composite Catto prop. For one, slipstream naturally wants to yaw the airplane left. If I spun left, the initial entry would "break" more sharply and cleanly to the left, but the spin rotation and pitch attitude would then vary a bit within the first turn. Left yaw produces a gyroscopic nose-up reaction, which made the spin fairly oscillatory and inconsistent within the first turn. I had to use momentary out-spin aileron at certain points to smooth out the spin. It's smoother now with the light prop.

When spinning right, gyroscopics produces a nose down reaction, causing the spin to adopt a more nose down and steady rotation, even though the initial spin "break" is more lethargic due to the opposing slipstream yaw. But I never paid attention to altitude loss between left and right spins.

In either direction, it stays level for an instant, and the wings drops to very close to 90* then the nose goes down.

Are you saying the airplane is rolling 90 degrees before the nose drops at all? This could cause some serious downgrades from the judges. The judges are looking for simultaneous movement about 3-axes - nose drop, yaw, and roll. Doing one of any without the other is a downgrade.

For competition spin entries, you want to ensure the airplane stalls first. You'll get called for "forced entry" if you apply rudder before the stall, or if you yank the stick back before the airplane stalls. Some technique hints - allow the airplane to climb very slightly into the spin entry. The judges will not notice, and in most airplanes it produces a better spin entry due to the lower airspeed at entry. At least fly perfectly level, but do not let it sink at all! You're watching your altimeter on your line into the spin entry. Also, as you near the spin, hold a slight amount of rudder in the direction you want to spin - not enough to visibly yaw the airplane, but enough so that the break goes decidedly one way or another without any wallowing around. Each airplane is a little different, but you generally want to climb very slightly into the spin, keep the stick steadily coming back, and at the first indication of a stall or buffet, quickly but smoothly apply full rudder, instantly followed by full aft stick.

Recovery BTW is essentially instantaneous; center the rudder and it is done. It is easy to over lead and come up short by most of the lead. 5* lead seems plenty.

That is very interesting. I've never flown an airplane that recovers from an actual spin (not spiral) that quickly. Does your ASI stay locked on zero indication throughout the entire spin? If not, then it's spiralling rather than spinning. I only ask because when I first started spinning the Clipped Cub that I also fly, I noticed that it would immediately stop within 5 degrees just be neutralizing the rudder. I thought that was odd, and I started looking at the ASI - it was increasing. I could also feel some G load on the airplane as it rotated. I've done hundreds of spins in other airplanes, and it seemed to rotate very much like a spin, but was actually spiralling. This Cub takes a blast of throttle during the entry to get both wings to stall and start to rotate. Then the ASI would stay locked on zero in a true spin, and recovery lead was about 90 degrees, which is what I've found for most light aerobatic planes I've flown. Again, I have no Waco experience, but to recovery from an actual spin in 5 degrees is very unusual. But if that's the way it is, that's a good thing!

And I guarantee you'll be the only airplane in the box where everyone stops to watch. Have fun.

Eric

 

[Cessna150C]

Competition is a great way to learn and practice new stuff. Really try to make a point to fly one this year. You will be glad you did.

When I started practicing for Primary last year, I found that my aerobatic skills increased much faster than when I just went out to "fly some acro". It's made me much more comfortable in my plane.

 

[Jeanie]

Hi Ernie, where are you in tenn? A friend and I are coming out in may for the ladies love taildraggers fly in maybe we can see you.

You'll have a ball at the "contest". What whiff says is true it's fun and folks are helpful. I went to my first one last fall. This year I'll probably just volunteer as I doubt I can be ready to fly sportsman by then.

 

[ebetancourt]

Hi Ernie, where are you in tenn? A friend and I are coming out in may for the ladies love taildraggers fly in maybe we can see you.

You'll have a ball at the "contest". What whiff says is true it's fun and folks are helpful. I went to my first one last fall. This year I'll probably just volunteer as I doubt I can be ready to fly sportsman by then.

About a hundred miles further east. I doubt I will go this year, but you never know.

 

[ebetancourt]

Are you running a wood or metal prop?
MT wood.

Are you saying the airplane is rolling 90 degrees before the nose drops at all?

Not quite, but close. In a level stall, the Waco never really breaks the way other airplanes I have flown break. I find it hard for example to do a falling leaf, because the wings basically rock, but the pitch hardly changes. I will hold it a little longer next time before I bring in the rudder and see if that alters things.

For competition spin entries, you want to ensure the airplane stalls first. You'll get called for "forced entry" if you apply rudder before the stall, or if you yank the stick back before the airplane stalls.

Pretty sure I eased the stick back slowly to the stop and waited for the beginning of the usual wing drop.

Some technique hints - allow the airplane to climb very slightly into the spin entry. The judges will not notice, and in most airplanes it produces a better spin entry due to the lower airspeed at entry. At least fly perfectly level, but do not let it sink at all! You're watching your altimeter on your line into the spin entry.

I did do a level stall, with no altitude loss, but I like the slight climb idea.

Also, as you near the spin, hold a slight amount of rudder in the direction you want to spin - not enough to visibly yaw the airplane, but enough so that the break goes decidedly one way or another without any wallowing around.

I will try this too.

That is very interesting. I've never flown an airplane that recovers from an actual spin (not spiral) that quickly. Does your ASI stay locked on zero indication throughout the entire spin?

Haven't been looking but I will next time. Since my results to the right are exactly what the book predicts, the possibility that the right is a spiral never entered my mind.

And I guarantee you'll be the only airplane in the box where everyone stops to watch. Have fun.

You bet! I'm really enjoying just getting ready.

Eric

Thanks for the suggestions. My goal is to figure this out at the basic level and then get some coaching. My goal is to attend a competition this year.

One thing that makes the Waco "diffferent" is weight. I am at 2,600 - 2,700# during these exercises.

 

[gismo]

That is very interesting. I've never flown an airplane that recovers from an actual spin (not spiral) that quickly. Does your ASI stay locked on zero indication throughout the entire spin? If not, then it's spiralling rather than spinning. I only ask because when I first started spinning the Clipped Cub that I also fly, I noticed that it would immediately stop within 5 degrees just be neutralizing the rudder. I thought that was odd, and I started looking at the ASI - it was increasing. I could also feel some G load on the airplane as it rotated. I've done hundreds of spins in other airplanes, and it seemed to rotate very much like a spin, but was actually spiralling. This Cub takes a blast of throttle during the entry to get both wings to stall and start to rotate. Then the ASI would stay locked on zero in a true spin, and recovery lead was about 90 degrees, which is what I've found for most light aerobatic planes I've flown. Again, I have no Waco experience, but to recovery from an actual spin in 5 degrees is very unusual. But if that's the way it is, that's a good thing!

And I guarantee you'll be the only airplane in the box where everyone stops to watch. Have fun.

Eric

Do you really mean "locked on zero" vs "locked on a constant airspeed"? With the possible exception of a flat spin where the wing with the pitot is the lower one (upright spin) I've never seen anywhere near zero airspeed in a spin. That includes a two place Pitts, Starduster, Citabria, Decathlon, SF260, Extra 300, CJ-6, and my own CP-65 which doesn't really like to stay in a spin and makes it quite obvious when it's changed from spinning to spiraling.

 

[whifferdill]

Do you really mean "locked on zero" vs "locked on a constant airspeed"? With the possible exception of a flat spin where the wing with the pitot is the lower one (upright spin) I've never seen anywhere near zero airspeed in a spin. That includes a two place Pitts, Starduster, Citabria, Decathlon, SF260, Extra 300, CJ-6, and my own CP-65 which doesn't really like to stay in a spin and makes it quite obvious when it's changed from spinning to spiraling.

You're right - for an honest spin, I really meant ASI indication somewhere below where the numbers on the face start, but most importantly that it doesn't move.

 

[ebetancourt]

Ya'all keep the knowledge coming. I started thinking about it. Since the T-28A most everything I have flown didn't do recoverable spins. I was thinking about lead in in it, then realized that was almost 48 years ago. BTW I think it took about 30* in it.

 

[dell30rb]

EI only ask because when I first started spinning the Clipped Cub that I also fly, I noticed that it would immediately stop within 5 degrees just be neutralizing the rudder. I thought that was odd, and I started looking at the ASI - it was increasing. I could also feel some G load on the airplane as it rotated.

I picked up on that in the clipped cub. Usually you can tell by about one turn if you are in a spiral or a full stall spin. The sight picture is about the same initially, but in a spiral, the G load will steadily increase with each turn. The nose will also point down a little farther and the wind noise pick up, but the most noticeable indication to me is the G load.

 

[flhrci]

So is the Waco as capable as a Pitts acrobatically or not? How much of a difference is there due to size and weight?


David

 

[whifferdill]

So is the Waco as capable as a Pitts acrobatically or not? How much of a difference is there due to size and weight?


David

The Waco will do everything a Pitts will do...just to a much lesser degree.

But seriously, the Waco has much less performance than a Pitts...just like a Pitts has much less performance than a MX-S. Aerobatics is basically endless combinations of loops, rolls, spins, and snaps - and the Waco will do all of those things, but it will do it with much less performance due to the Waco's much slower roll rate, and lower power-to-weight ratio. I'd guess the Waco rolls in the 60 degree/sec. range. My Pitts rolls 180 deg/sec. An MX-S rolls over 400. The Pitts can do about 2 vertical rolls before sliding backwards. The Waco might get coaxed into 1/2 on a cold day if you pull hard from Vne and let the engine turn up to...well forget about redline. So like I say, the Waco will do most things a Pitts will do, but to a lesser degree. You won't see a Waco flying in the Advanced Category at an IAC contest. But in the right hands it could do OK in Sportsman. It's biggest competition aerobatic handicap is lack of inverted systems. You don't necessarily need them in Sportsman, but it's easier to do better with them.

 

[ebetancourt]

I think power to weight (and drag) might be a bigger issue than inverted systems. Even primary will be all about energy management.

But if there are extra points for grace...

My goal is simple: not zero any maneuvers.

Ernie

 

[whifferdill]

I think power to weight (and drag) might be a bigger issue than inverted systems. Even primary will be all about energy management.

But if there are extra points for grace...

My goal is simple: not zero any maneuvers.

Ernie

Yeah power is a problem when your engine quits during the level roll. Do you have a 300 hp Jake? I'd imagine your Waco at least has the performance of a 115 hp Citabria, which is the baseline airplane for min. performance requirements when IAC determines the Sportsman Known sequence each year. Believe it or not, most of the Sportman sequences have had better energy flow than the Primary sequence, which has been unchanged for 6-7 years. The Primary sequence places the roll after the 180 turn, which isn't good energy management for low-performance airplanes. That'll be the most challenging figure for you to score well. And remember, you can take an interruption after the turn if you want, and reposition for as much airspeed as you want for the roll. You can't dive for speed between figures. The penalty for interrupting in Primary is so small (fraction of a percentage point in your overall score) that it's worth it if it allows you to do the roll significantly better.

 

[ebetancourt]

Yeah power is a problem when your engine quits during the level roll. Do you have a 300 hp Jake?

Fuel injected 275. But with all that inertia it won't slow down... much.

I have an aversion to negative Gs without a parachute, and mine is off to repack. I plan to try the slow roll after a 180. The Waco has a much better roll rate than the Citabria, decent even at 85 where I start a split S to get rid of altitude when I get through playing. Think graceful, not like those flat engine gnats. I can maintain 110, maybe more, after a 180, we'll see how a slow roll works at that speed.

 

[whifferdill]

Fuel injected 275.

Great, then fuel in the injection system should keep the engine running long enough to get through the brief negative G you'll see flying the Primary and Sportsman sequences. Dang, that thing must be fun.

I have an aversion to negative Gs without a parachute, and mine is off to repack.

I've never gone negative in an open cockpit plane. I can see how that would be a mental thing. Do you have a double lap belt (two different attach points)?

 

[ebetancourt]

I've never gone negative in an open cockpit plane. I can see how that would be a mental thing. Do you have a double lap belt (two different attach points)?

Hooker 5pt & lap belt

Once upon a time I went flying in my Citabria while recovering from surgery on my right hand. Had a cast on but fingers could hold a stick fine. Did some positive G playing including hammerheads which the Citabria does OK but is the only maneuver I had ever screwed up royally in it.

After landing I went to unlatch the harness. Sometime during the flight, the cast had done it for me...

Now I'm paranoid about checking seatbelt frequently

 

[ebetancourt]

Re: Spin left ;-) update

So I had a little (story of my life) time today and went up for a short flight. I started with a level power off stall to see if I remembered correctly. My way is to simply keep the nose up without increasing stick pressure. Eventually the stick is all the way back and you stall. Yep, the Waco nose does not come down very much. Not sure you could see it from the ground. I held the stick all the way back and basically did a falling leaf. At most the nose was down 10* and up about the same over time. The wings rock side to side and it is a lot of work on the rudders to keep that from becoming too much. I held the stick full back for about 700 feet and nothing ever changed.

Then I did a spin to the left. Nose goes down very little, wing drops to almost 90* then the nose follows down. Airspeed is static at the bottom of the range and doesn't move, so no question its a spin. When I have more time I will repeat to the right, but I am pretty sure that is a spin as well, just faster down. And yes, recovery is almost instantaneous.

My promise to me is to take a week off from work soon and fly at least twice a day, with a goal of flying the whole primary sequence by the end of the week. We'll see if the pilot is up to that.

 

[stearmann4]

Ernie,

Congrats on your decision to compete, we need more old biplanes in IAC! I'm not overly familiar with the Waco's aerobatic capabilities, but I'm assuming it's similar to the Stearman's in at least that they both have massive drag characteristics and relatively low power. I'm guessing you're running at least an R-755 Jacobs, but if you're flying a Continental R-670 I highly recommend the McCauley metal prop pitched to at least 10.7. I also installed new Hooker 5-point harnesses which gives me some piece of mind and a G-meter. You'll really appreciate them when you start doing the slow rolls which seem to be the cornerstone for a lot of the competition maneuvers. I would also maybe have your mechanic take a special, in depth look at the integrity of your rudder cables and all the flying wires and attach hardware. I end up pulling around 5g max mainly because I have to get going to fast down hill to have any energy remotely approaching vertical or inverted.

You'll always come in last at any contest, but everyone stops what they're doing and looks skyward when the big, slow biplane enters the box! Kinda like a train wreck, they can't take their eyes off it.

Good luck!

Mike-

 

[stearmann4]

Ernie,

Congrats on your decision to compete, we need more old biplanes in IAC! I'm not overly familiar with the Waco's aerobatic capabilities, but I'm assuming it's similar to the Stearman's in at least that they both have massive drag characteristics and relatively low power. I'm guessing you're running at least an R-755 Jacobs, but if you're flying a Continental R-670 I highly recommend the McCauley metal prop pitched to at least 10.7. I also installed new Hooker 5-point harnesses which gives me some piece of mind and a G-meter. You'll really appreciate them when you start doing the slow rolls which seem to be the cornerstone for a lot of the competition maneuvers. I would also maybe have your mechanic take a special, in depth look at the integrity of your rudder cables and all the flying wires and attach hardware. I end up pulling around 5g max mainly because I have to get going to fast down hill to have any energy remotely approaching vertical or inverted.

You'll always come in last at any contest, but everyone stops what they're doing and looks skyward when the big, slow biplane enters the box! Kinda like a train wreck, they can't take their eyes off it.

Good luck!

Mike-

 

[whifferdill]

You'll always come in last at any contest...

Mike, I must disagree with this. The focus of competing shouldn't be how well you place, BUT it is possible to do well in the Waco. The Waco rolls a little better than the Stearman, and his has 275 hp and fuel injection, which gives you power during the brief negative G segments. This airplane has the performance to fly Primary or Sportsman perfectly well. I've seen a Citabria 7KCAB win Sportsman against a field of Pitts' and Decathlons. Your points come from accuracy of 45 and vertical lines, staying on heading, stopping your spins on heading, rolling on a straight line, centering your rolls on 45 lines, flying round looping segments, and staying in the box. The Waco can do all these things in Primary and Sportsman. You don't get extra points for high roll rate, long lines, or lots of speed. That's the nice thing about Primary and Sportsman - it truly is about the piloting and not the airplane...within reason. A Curtis Jenny won't do very well, but there is a wide range of suitable airplanes for Sportsman. At our last contest, we had a Dehavilland Chipmunk finish a very close second behind a Pitts S-2C (and ahead of a Giles and 4 other airplanes) in Sportsman.

but everyone stops what they're doing and looks skyward when the big, slow biplane enters the box!

True that!

Eric

 

[ebetancourt]

Hi Mike,

I think the pilot will be this Waco's limitation. This is a '99 Classic Waco with the 275 Jake and an MT prop. I have never been in a Stearman (unfortunately) but my sense is that the Waco is a lot cleaner based on cruise speeds. With a Vne of 214mph, assuming I can keep the altitude loss in the spin low enough to give me altitude I should be able to build enough speed for everything until the 180. Depending on what I work out, I can take Eric's suggestion and go out and build speed for the slow roll if I need it. I have played with the 45 up and I don't think the airplane will have a problem since I can enter the box around 160 or so without much of a problem. I used to have a problem getting that fast trying to keep the RPM up but below the redline. I have that worked out now and it shouldn't be a problem. The MT is way better than the Sensenich, and that helps.

Ernie