Towing is an interesting dance.
The end goal for everyone included is to get you into the air safely and in "good position". I call it "Good Position" to describe being where you want to be to maximize your flight... for example... for a thermalling flight, you want lift, but for a pattern tow you want to be in the "staging area". Yesterday would be a good example of one of the rare times where you'd want to be towed downwind... because that's where the gaggle is.
For the most part, we're deaf to each other. There aren't a lot of ways to communicate.
I do my best to guess what the guy behind me is after. Hopefully I'm guessing right most of the time.
I know you're left back there to guess at a lot of stuff too. Sometimes right, sometimes wrong, and sometimes the stuff that looks like it matters actually doesn't.
Overall, I think everyone will be happy to know that in general, ya'll tow very well. Thank you btw... it makes my job much easier.
And you want my job to be easy... because, it makes your life better. If I'm not having to deal with other things, it leaves me free to get you into better position. Like, if I'm having to work hard just to help you stay on tow for example, I have very little time to worry about where the thermals are and how to put you in one.
Some of you may have encountered me asking about tow speeds when I switch planes.
This is because the airspeed sensors on every tug are different (and generally suck). The reason this is important is because until I know what our target speed is, I have to guess... more work, less time to think about thermals.
An other example of "if my life is easier, then your life gets easier" is... Russell's electric trim tugs are simplicity to tow with and make it super easy to make the tows much smoother.
So here's some tips from the other end of the rope.
My #1 piece of advice... don't get creative.
The easiest tows are "by the book". Clever tricks don't work (for various reasons).
#2 Smooth.
Smooth is almost always better. I can not emphasize this enough.
You can be assertive and "get things done" while still being smooth. Sharp and aggressive movements are rarely helpful. I often want to strangle Pagen for introducing the notion of "Bumping". I'm sure it's a great tool for teaching mountain flying, but on tow it makes things harder. (It's sh*t for mountains too, but it sometimes helps students learn... then they hopefully refine their technique and smooth out later)
#3 Wings level.
Above all else, especially near the ground... wings level.
Get up to the tug or down to the tug AFTER you have your wings level.
(more after 4)
#4 Towline tension is a very important idea.
It's especially relevant to weak links, although it's important to many things in towing.
When you takeoff, it's extremely likely that you'll hit the prop wash. It is also very predictable. In the desert, you can actually see it (dust kicks up). You will encounter it where I start. So where the tug is on the runway when we're line tight and ready to go... that's where you'll hit it.
Pull in as you do.
Shockloading weaklinks breaks them... that' the idea. Hitting the prop wash... is well "hitting" something. If you're high drag because you're pushing out, you hit with far more force. The opposite is true if you're pulling in. A slight pull in relieves a lot of towforce. You don't want go overboard and slack the rope of course because when it unslackens, it shock loads... but if you can slightly unload things as you fly through the prop wash, you will have a much better time.
Pitch (wings level part2)
Don't be in too much of a rush on pitch.
My best advice is to keep moving in the right direction. You don't need to be laser accurate on tow, but keep moving in the right direction. If you're a little high, be coming down... a little low, be coming up. As long as you're closing the gap, you're good. Don't rush it. If you're not closing the gap... if things are getting worse... then you're not doing something right... get on it... get it heading in the right direction.
Why is that so important?
Because of towline tension. If you're too aggressive in fixing things, you'll cause a lot of abrupt tension changes.
Remember, the air is exponential... you can generate a hell of a lot of force with those wings very quickly.
Be smooth.
#5 Stay in position.
"A little high because... " or "A little low because...." is a bad idea in my book.
Stay in position. Your life will be better for it.
There are many reasons for this.
If you sit high on me, I'm going to try to get you back on the horizon. I know what speed your glider tows at BTW. Once you're back on the horizon, I will seek this speed.
If I slow down to help you get back on the horizon, and you pop back up to where you were... after a few times, I stop helping.
You don't want that.
I stop because you're wearing me out.
Imagine towing too fast... it wears you out right?
I do 50-80 tows on a busy day. You've got bar pressure right? I've got stick pressure. Try doing 50 fast tows. Yeah, it can get sucky really fast.
So, if you're a little high, I'll try to come up to you... but I'm not going to hold that speed.
If you pop back up as I get to you, you're asking me to.
That ain't going to happen.
At that point, I set "trim" (I know the stick pressure that equals the correct tow speed for you) and I turn on autopilot.
The result?
We fly faster. Why? because you're pulling my tail up, which speeds me up.
You also don't want to sit high on me as we also climb like ass. That's a much higher drag profile... remember that your wings are exponential in force.
So please stay in position.
It'll make your life a lot easier.
There's more to it (there have been some very interesting conversations on the topic lately) but I've gotta get to work.
More later.
At least this gets the ball rolling.
Jim
The view from the other end of the rope
Moderator: CHGPA BOD
Re: The view from the other end of the rope
Ok, I've been getting some excellent feedback, so I'll try and address that now, and there's a bit more to add (hopefully I can remember it)....
Here goes.
So when I'm talking about "not getting creative", a lot of that boils down to staying in position.
I know there are tug pilots that want people to hang low on them because it can relieve stick pressure. Mostly I hear about this from 582 pilots for whatever reason. That's a "creative" bit in my book and it's not my cup of tea. I want people in position. To ask them to be "sorta in position, but sorta not" is asking a bit much. K.I.S.S right?
Other people seem to have gotten the idea that hanging high is a good thing. They're trying to fix a perceived problem and the trouble is that not only does it not fix it (it makes it worse) it's that you create a host of other problems by trying to fix the first one.
Some of it as well I suspect comes from flying with newer tug pilots. We've seen this a lot with HG pilots transitioning to the tug.
See, in a HG when you hit lift you push out right?
That instinct kinda screws things up in the tug. In the tug, you push over.
When you're flying behind a tug that slows down in lift, they go to the moon and leave you in the dirt.
If I was stuck behind someone doing that, I'd probably sit high on them as well.
There are many bad things that happen when you do that, but let's talk about how it's supposed to work...
When I hit lift, I do a few things to try and help out.
In lighter lift with softer edges, I just speed up... then I wait. When you hit it, I slow down and we climb together. This works most of the time.
If we're in strong stuff however, simply pushing over isn't going to work... I'll still climb fast and you'll be left in the dust as you hit a sharp edge... not thrilling.
Now, before we talk about technique two...
Remember... don't jam the bar out to try and catch me!
Close the gap... SMOOTHLY.
If you jam the bar out, it's the same scenario as the prop wash... high tension and a sharp force.
Ok, so what I do in strong stuff... is turn.
In a turn, you have a lot of control over the tow force.
Go to the outside of the turn and you speed up and climb...
Slide to the inside of the turn and the force goes decreases.
So, if we're slamming into lift and I'm going to shoot to the moon, I turn. This allows you to cut the turn to the inside if you need to.
NOTE HOWEVER that cutting the inside of turns as a practice is a bad idea.
Why?
Because you're attached to my tail.
If you cut the inside, you slow my turn. So if we're trying to turn and you're always sitting on the inside, we're going to have a lot of trouble turning. We're also going to turn very inefficiently.
What I was talking about in regards to your wings being "Exponential" goes back to the nature of wind.
As we know, the power of the wind's force changes exponentially with it's speed.
So twice the wind is four times the force.
Four times the speed isn't eight times the force, it's sixteen.
And so on.
On tow, you're being pulled through the sky. Changes in pitch (in particular) have an increasing effect on the tug... and not a linear increase... they ramp up very quickly.
If you've ever locked out, you know this intimately.
It doesn't smoothly get stronger and stronger... it gets a little stronger then a good bit stronger then "oh my god stronger".
That's "exponential".
Sunny calls it "falling off the beach ball".
Standing on a gigantic beach ball... take a step to the left... you tip a little bit... take an other and you tip a lot... take an other and you're falling off the ball.
Our brains don't instinctively work that way.
So when people make what they consider to just be a "big" input, on my end, it's huge... and on the weaklink, it's huge as well.
Well, that's my best stab at that stuff.
Hopefully it makes some sense.
Here goes.
So when I'm talking about "not getting creative", a lot of that boils down to staying in position.
I know there are tug pilots that want people to hang low on them because it can relieve stick pressure. Mostly I hear about this from 582 pilots for whatever reason. That's a "creative" bit in my book and it's not my cup of tea. I want people in position. To ask them to be "sorta in position, but sorta not" is asking a bit much. K.I.S.S right?
Other people seem to have gotten the idea that hanging high is a good thing. They're trying to fix a perceived problem and the trouble is that not only does it not fix it (it makes it worse) it's that you create a host of other problems by trying to fix the first one.
Some of it as well I suspect comes from flying with newer tug pilots. We've seen this a lot with HG pilots transitioning to the tug.
See, in a HG when you hit lift you push out right?
That instinct kinda screws things up in the tug. In the tug, you push over.
When you're flying behind a tug that slows down in lift, they go to the moon and leave you in the dirt.
If I was stuck behind someone doing that, I'd probably sit high on them as well.
There are many bad things that happen when you do that, but let's talk about how it's supposed to work...
When I hit lift, I do a few things to try and help out.
In lighter lift with softer edges, I just speed up... then I wait. When you hit it, I slow down and we climb together. This works most of the time.
If we're in strong stuff however, simply pushing over isn't going to work... I'll still climb fast and you'll be left in the dust as you hit a sharp edge... not thrilling.
Now, before we talk about technique two...
Remember... don't jam the bar out to try and catch me!
Close the gap... SMOOTHLY.
If you jam the bar out, it's the same scenario as the prop wash... high tension and a sharp force.
Ok, so what I do in strong stuff... is turn.
In a turn, you have a lot of control over the tow force.
Go to the outside of the turn and you speed up and climb...
Slide to the inside of the turn and the force goes decreases.
So, if we're slamming into lift and I'm going to shoot to the moon, I turn. This allows you to cut the turn to the inside if you need to.
NOTE HOWEVER that cutting the inside of turns as a practice is a bad idea.
Why?
Because you're attached to my tail.
If you cut the inside, you slow my turn. So if we're trying to turn and you're always sitting on the inside, we're going to have a lot of trouble turning. We're also going to turn very inefficiently.
What I was talking about in regards to your wings being "Exponential" goes back to the nature of wind.
As we know, the power of the wind's force changes exponentially with it's speed.
So twice the wind is four times the force.
Four times the speed isn't eight times the force, it's sixteen.
And so on.
On tow, you're being pulled through the sky. Changes in pitch (in particular) have an increasing effect on the tug... and not a linear increase... they ramp up very quickly.
If you've ever locked out, you know this intimately.
It doesn't smoothly get stronger and stronger... it gets a little stronger then a good bit stronger then "oh my god stronger".
That's "exponential".
Sunny calls it "falling off the beach ball".
Standing on a gigantic beach ball... take a step to the left... you tip a little bit... take an other and you tip a lot... take an other and you're falling off the ball.
Our brains don't instinctively work that way.
So when people make what they consider to just be a "big" input, on my end, it's huge... and on the weaklink, it's huge as well.
Well, that's my best stab at that stuff.
Hopefully it makes some sense.
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Larry Huffman
- Posts: 42
- Joined: Fri Feb 11, 2005 12:12 am
Re: The view from the other end of the rope
This is some great stuff Jim. I would like to emphasize something and add something. I agree with Jim about the importance of managing the tow line tension. I believe that it may be the most important thing. It takes a lot less tension than we think and this can be seen most readily while towing in smooth air. By keeping the tension low we reduce our potential for lockout, reduce our work load, and make it easier on the tug pilot.
I would like to add that it is important to understand the relationship between the tug and the glider being towed. If the glider slows down and increases the tow line tension it puts a lot more drag on the tug and its climb will slow. Conversely if the glider reduces the tension by speeding up the tug can climb faster. If the glider gets high on the tug rather than aggressively trying to get back down the glider pilot can speed up smoothly enough to reduce the line tension. The glider will come down slowly but more importantly the reduction of drag on the tug will let it climb faster helping to get back in proper position. If the glider gets low on tow the glider pilot can slow down smoothly increasing the line tension. This will result in the glider climbing faster but also the tug will now climb slower making it easier to get back into position.
Larry
I would like to add that it is important to understand the relationship between the tug and the glider being towed. If the glider slows down and increases the tow line tension it puts a lot more drag on the tug and its climb will slow. Conversely if the glider reduces the tension by speeding up the tug can climb faster. If the glider gets high on the tug rather than aggressively trying to get back down the glider pilot can speed up smoothly enough to reduce the line tension. The glider will come down slowly but more importantly the reduction of drag on the tug will let it climb faster helping to get back in proper position. If the glider gets low on tow the glider pilot can slow down smoothly increasing the line tension. This will result in the glider climbing faster but also the tug will now climb slower making it easier to get back into position.
Larry
Re: The view from the other end of the rope
Jim and Larry
This is great stuff. Thanks for writing all this up. I think that we should re-post this every spring as we start the tow season.
I will keep all this in mind when I am towing at Big Spring!
Tom McGowan
This is great stuff. Thanks for writing all this up. I think that we should re-post this every spring as we start the tow season.
I will keep all this in mind when I am towing at Big Spring!
Tom McGowan
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Patrick Halfhill
- Posts: 10
- Joined: Mon Aug 18, 2008 1:36 pm
Re: The view from the other end of the rope
Or weekly for people like me
Re: The view from the other end of the rope
Hey guys.
I've had some good conversations with people about this stuff lately. I'm glad it's been useful thus far.
Here's an interesting bit that I was a little hesitant to bring up because it's specific to me and goes a little against convention.
So, I'll start this off with some warnings, disclaimers and why I'm technically allowed to even recommend this.
We tow under FAR 91.309...
§91.309 Towing: Gliders and unpowered ultralight vehicles.
91.309(a)(5) The pilots of the towing aircraft and the glider or unpowered ultralight vehicle have agreed upon a general course of action, including takeoff and release signals, airspeeds, and emergency procedures for each pilot.
So, what I'll be talking about is specific to me.
I know other tow pilots do this as well (most btw), but you'll need to talk to them about it... the regs are that we've agreed and I can't agree for them.
Convention is that when you release the towline, you turn right and I turn left.
This comes from sailplane protocol. Sailplanes can outrun the tow plane, so when they let go, where they go is pretty important. A normal tug doesn't dive at 2,000fpm on release like we do. They can also more easily run into the wake of a normal tow plane. So the FAA would prefer that tugs and gliders didn't run into each other. Pretty reasonable really.
Towing a hang glider is a bit different however. When you release, you'll be hard pressed to catch me. I'm not recommending trying. I'm just illustrating the difference.
With all that in mind. Here's how it goes...
There's pretty much only one reason I ever wave someone off while turning. It's because we're in lift.
If we're not in lift, I'll level my wings and wave you off.
In that case, by all means, turn right.
However, if we're turning left and I'm waving, I'm trying to keep you in lift... feel free to keep turning left.
When you let go, I dive.
Anyone that's towed behind me knows what I'm talking about. I'm not shy about it. I don't "speed up a little", I tend to point the nose at the earth.
This puts a lot of air between us in a rapid fashion... that's the idea.
It's also generally a good idea to sniff around a bit if I wave you off in a turn... even if you're not booming up. Again, I generally only wave people off in a turn if we're in or near lift. Otherwise, why bother? You can sense the lift better than I can, so don't take my word for it, but consider it a suggestion.
At the end of the day, it's your butt on the line, so do what you feel is safe.
I just don't want you to think that I'll be offended if you turn left.
Jim
I've had some good conversations with people about this stuff lately. I'm glad it's been useful thus far.
Here's an interesting bit that I was a little hesitant to bring up because it's specific to me and goes a little against convention.
So, I'll start this off with some warnings, disclaimers and why I'm technically allowed to even recommend this.
We tow under FAR 91.309...
§91.309 Towing: Gliders and unpowered ultralight vehicles.
91.309(a)(5) The pilots of the towing aircraft and the glider or unpowered ultralight vehicle have agreed upon a general course of action, including takeoff and release signals, airspeeds, and emergency procedures for each pilot.
So, what I'll be talking about is specific to me.
I know other tow pilots do this as well (most btw), but you'll need to talk to them about it... the regs are that we've agreed and I can't agree for them.
Convention is that when you release the towline, you turn right and I turn left.
This comes from sailplane protocol. Sailplanes can outrun the tow plane, so when they let go, where they go is pretty important. A normal tug doesn't dive at 2,000fpm on release like we do. They can also more easily run into the wake of a normal tow plane. So the FAA would prefer that tugs and gliders didn't run into each other. Pretty reasonable really.
Towing a hang glider is a bit different however. When you release, you'll be hard pressed to catch me. I'm not recommending trying. I'm just illustrating the difference.
With all that in mind. Here's how it goes...
There's pretty much only one reason I ever wave someone off while turning. It's because we're in lift.
If we're not in lift, I'll level my wings and wave you off.
In that case, by all means, turn right.
However, if we're turning left and I'm waving, I'm trying to keep you in lift... feel free to keep turning left.
When you let go, I dive.
Anyone that's towed behind me knows what I'm talking about. I'm not shy about it. I don't "speed up a little", I tend to point the nose at the earth.
This puts a lot of air between us in a rapid fashion... that's the idea.
It's also generally a good idea to sniff around a bit if I wave you off in a turn... even if you're not booming up. Again, I generally only wave people off in a turn if we're in or near lift. Otherwise, why bother? You can sense the lift better than I can, so don't take my word for it, but consider it a suggestion.
At the end of the day, it's your butt on the line, so do what you feel is safe.
I just don't want you to think that I'll be offended if you turn left.
Jim
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Larry Huffman
- Posts: 42
- Joined: Fri Feb 11, 2005 12:12 am
Re: The view from the other end of the rope
Thanks for starting and continuing this thread Jim.I have flown at places where they insisted on the glider turning right upon release. However I do agree with you. I have found that the reduction of drag on the tug when the glider pilot releases causes a surge in speed for the tug that causes it to pull away from the glider even if it continues to climb which is often the case. There is a lag between glider release and tug pilot reaction time. Even a very small lag causes a separation between glider and tug.
Larry
Larry
Re: The view from the other end of the rope
Good point Larry.
That makes sense... it's not so much about the dive (although that helps after the fact), but it's more about gliders slowing down because of the release.
That makes sense... it's not so much about the dive (although that helps after the fact), but it's more about gliders slowing down because of the release.
Re: The view from the other end of the rope
Just an observation about releasing... After a recent step up to a topless from the U2, I was surprised (though I shouldn't have been) at how hard it is to turn away from the tug after cutting away. Close to 1/2 VG and all...
Like, REALLY different.
I will have to pull in for speed/response quite a bit more aggressively than before. Nice to know that there will be natural separation in case I'm behind the curve... But still, need to do better!
Also very good to hear Jim's thoughts about staying with the turn when released in lift. That certainly expands the options!
MarkC
Like, REALLY different.
I will have to pull in for speed/response quite a bit more aggressively than before. Nice to know that there will be natural separation in case I'm behind the curve... But still, need to do better!
Also very good to hear Jim's thoughts about staying with the turn when released in lift. That certainly expands the options!
MarkC
Re: The view from the other end of the rope
I thought of something else today. (I get a lot of time to think)...
Pilots often apologize for staying on tow.
I've never understood this.
Often it's staying on tow through lift.
The only thing I can come up with is that they somehow feel like they're "tying up the tug", but I often hear the same thing when there is no one else towing?
Here's the deal....
You love to fly right?... well, so do I. So it's pretty impossible to "waste my time" in the air. We're flying!.. I'm in happyland.
On the ground is a different story.
I'm sure you can relate to not wanting to wait around on the ground while roasting in your harness. A bit is necessary, but after a while it gets pretty miserable. So you try to be as efficient as possible. My world is not too dissimilar. Sitting on the ground idling while backing in the sun is a less than pleasant place to be. I'd much rather be either in the air or hiding in the shade under the wing.
So my advice is to either be ready, or wait.
If you're not ready, that's fine. Don't push up to the ready-line until you are. I'll land and pull in, turn off the engine, grab a water, hide under the wing, take a leak or any number of little things that I can't do waiting with the rope tight and the engine idling.
Pulling up when your ready helps you as well. Not only do you have a much happier tug pilot (happy tug pilots are better at finding lift), but I also have a better idea of what's going on with the air as I was just there a second ago. Being ready also makes the line move much more efficiently which benefits everyone. I have a far better chance of putting you in lift and getting your buddies into lift with you. When things aren't running well, it gets a lot harder to do so.
So if you want to move things along, don't worry about staying on tow.
Think about it... how much do you slow things down by sinking out?
The way to "not tie up the tug" is to be ready.
Jim
Pilots often apologize for staying on tow.
I've never understood this.
Often it's staying on tow through lift.
The only thing I can come up with is that they somehow feel like they're "tying up the tug", but I often hear the same thing when there is no one else towing?
Here's the deal....
You love to fly right?... well, so do I. So it's pretty impossible to "waste my time" in the air. We're flying!.. I'm in happyland.
On the ground is a different story.
I'm sure you can relate to not wanting to wait around on the ground while roasting in your harness. A bit is necessary, but after a while it gets pretty miserable. So you try to be as efficient as possible. My world is not too dissimilar. Sitting on the ground idling while backing in the sun is a less than pleasant place to be. I'd much rather be either in the air or hiding in the shade under the wing.
So my advice is to either be ready, or wait.
If you're not ready, that's fine. Don't push up to the ready-line until you are. I'll land and pull in, turn off the engine, grab a water, hide under the wing, take a leak or any number of little things that I can't do waiting with the rope tight and the engine idling.
Pulling up when your ready helps you as well. Not only do you have a much happier tug pilot (happy tug pilots are better at finding lift), but I also have a better idea of what's going on with the air as I was just there a second ago. Being ready also makes the line move much more efficiently which benefits everyone. I have a far better chance of putting you in lift and getting your buddies into lift with you. When things aren't running well, it gets a lot harder to do so.
So if you want to move things along, don't worry about staying on tow.
Think about it... how much do you slow things down by sinking out?
The way to "not tie up the tug" is to be ready.
Jim