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By RobertKesselring
#378639
Some have expressed concern over my launch technique, to the point of hijacking other threads. While the hijacking is not particularly appreciated, I do appreciate the concern for my safety and the suggestions for improvement. Now that I've had a chance to work on my launch a bit, I think it has improved. I'm sure there is still room for further improvement, so, suggestions welcome.
[youtube]http://www.youtube.com/watch?v=Mnk8-Un5sXs[/youtube]
This was my latest 2 launches from 2 angles each. On the first, I'm aware that I let my nose up a little, the second, I think, was pretty good.
The first had a 3-6 mph headwind, the second was no wind at all.
User avatar
By red
#378641
Robert,

Hmm . . . C+, and B-

Both launches would (and did) do the job. An F grade here can get costly, in more ways than one.

In more wind, you might have improved on each launch, but it would be better if you did more with what you have. Consider (always) that the wind travels up the slope of the hill, parallel to the ground. Rotate each launch picture (from the side view) until you are running across flat ground there, and see if you still like what you see. If that mental picture somehow eludes you, there is free movie software available which can do it for you on the screen.

Without talking with you first, I would guess that you are looking at the horizon ahead to "set" your Angle of Attack at launch. Forget the horizon, except as a reference for "wings level." The AoA for launch is never set from the horizon. You need to be looking down the slope, and set the AoA from that sight angle, not from the horizon. An AoA that is higher than necessary just holds you back, and it can absolutely ruin a good launch effort. You can see this hindrance (somewhat) in the first launch. Even if the glider is lifting you, you do not want to become airborne until you have plenty of airspeed. Fly the glider down the slope as you add speed, just touching (digging) with the toes.

The launch runs were smooth, no doubt, which is a good way to go. Add as much "aggressiveness" to each launch (and forever, my friend) as you can, without lunging forward and/or popping the nose up as you start. Speed at the expense of smoothness is not a good trade. As long as there is good ground in front of you, you can always add speed to a smooth launch (as in the last part of the second launch).

Your thoughts are welcome here.
User avatar
By mbadley
#378643
My impression is that with that glider and that slope - you are doing fine! You may not find that to be the case if you step up to a more high performance wing or a less forgiving flatter slope or conditions that warrant a more technical launch (like a no-winder) Some day you will experience that stuff and I hope you adjust to it so that you don't mush off and whack. It can happen to the best of us - I know, I've blown it a time or two (even though I'm NOT the best of us, for sure...).

You are developing much better habits and I can see that you are an analyzing S.O.B. - so keep at it and some day you should come out here to the west coast for some real mountain flying! :thumbsup:
User avatar
By NMERider
#378653
Robert, On your first launch you changed your grip from grapevine to bottle grip prematurely and as a result of this your nose pops up and you become airborne prematurely as well. Luckily the air was smooth and the slope was steep. I have been reading old accident reports from USHPA and the blown launch issues of past seem to keep rearing their ugly heads. I guess it's a never-ending issue.

One of the article I read discussed this issue of changing grips from grapevine to bottle grip and it made good sense as follows:
When we hold the glider with a grapevine grip the control bar is naturally positioned closer to the pilot and so the nose of the glider stays down. When we use the bottle grip our wrists are bent back which forces our forearms out and the control bar is pushed away from our bodies. As a result, the nose pops up.

It should be possible to stay in the grapevine grip much longer and build up more airspeed before switching grips. Also, with practice it's equally possible to switch grips early without allowing the glider's nose to pop. For now, I would suggest that you hold the grapevine grip until the glider is pulling you away from the ground.

Keep up the good work!
Jonathan
By JackieB
#378666
I don't have many more launches than you do, but your first launch made me nervous. Your AoA is a bit high initially (IMHO), but it definitely increases considerably before you are launched and away from the hill. Stop your video at :10 and look at the AoA. It's very high, and I am pretty certain that the next couple of seconds (flying away from the hill at :12 and :13) show that the glider is mushing along partly stalled. Then by :14, the glider really starts flying.

This is just my opinion and perhaps Red, NME, or more experienced pilots will see it differently.

As to what to do, I can tell you that if this was me (and it could be, I don't claim to be any expert on launching), I'd head to the big hill at Lookout and work with an instructor until I was flying away at precisely the correct AoA every single time. Then, I'd go to the mountain and ask for the same instruction and I'd film every launch.

I applaud you for posting this video and asking for input. That's how we can improve, and I promise to do the same the next time I am at Lookout and practicing my launches.
User avatar
By Takeo77
#378667
I'm following the topic eagerly as I, too have the same problem. It's painful and frustrating to be told my launches suck, but it is what it is, the proof is in the pudding and the only way forward is to improve. I welcome comments on my latest launch as well.

[youtube]http://www.youtube.com/watch?v=Sr_HmQf4mo4[/youtube]
User avatar
By trnbrn
#378670
What works well for me is setting my AOA then, rather than walk, jog, run... I start with my feet side by side, lean forward till I am forced to take a step then I execute an acceleration into my aggressive run. Seams to help me keep my AOA where I want it. Think I read about this technique from a Ryan Voight article. Don't hold me too that though.
User avatar
By Flying Circus
#378677
I have seen some pilots go from grapevine grip to base bar and omit the bottle grip then only use the bottle grip for landing. That way you cannot pop the nose while changing hand grip on takeoff. Any thoughts or advice on this ?
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By Nicos
#378680
Good comments here.

@Flying Circus: changing grips low to the ground is normally something to avoid unless there is a good reason (to have control in case you encounter unexpected turbulence etc). I recently fell into the habit of grabbing the basebar on launch before leaving the ground, mostly because of complacency. It took me the best part of a season to change that habit.

Bottle grip for landing is OK as long as you have your hands low on the DTs in order to be able to pull in for speed, then let them slide up the DTs at trim speed ready for flaring. Personally, I often do 'one hand up, one hand down' on approach and transition at trim speed so I can have plenty of airspeed.
User avatar
By Darbbb
#378681
If you take red's suggestion and "flatten out" the slope of your launch, then your angle of attack is as pictured below. I hope this helps you see the problem. Ditto JDs suggestion about maintaining a grapevine grip all the way through your run. I used to turn my hands too, but stopped doing that after JR suggested it was not the best idea.

Brad.
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User avatar
By red
#378688
Robert,

I'd rather see this done as a video, not as a single frame, but it's a busy night here. 8)

What would you tell this guy, if you saw him trying to run the glider across the LZ?

Image


:mrgreen:
User avatar
By RobertKesselring
#378690
red wrote: Without talking with you first, I would guess that you are looking at the horizon ahead to "set" your Angle of Attack at launch. Forget the horizon, except as a reference for "wings level." The AoA for launch is never set from the horizon. You need to be looking down the slope, and set the AoA from that sight angle, not from the horizon.
Setting my AoA from the horizon is what I was taught at LMFP. From your explanation, it is obvious that is not optimal, but I can see why they teach that way. On a flat slope, setting the nose angle to the horizon is probably just about right. On a steep slope it creates a greater angle between where the glider is pointed and the direction of travel, but steep slopes give you a larger margin for error, so the horizon method gets you closer to the correct AoA in the conditions when it matters the more.

Now that I've recognized that the make-do method that I've used to date is sub-optimal, the next question is...

What do I use instead of the horizon as a reference. I know you said to set my AoA relative to my sight angle down the slope. How high above my sight line would you suggest I set it? Can you suggest any visual cues I could use? Line X up with Y kind of thing?

I am accustomed to having my straps go tight within a step or 2. I'm concerned that a lower AoA may allow the glider to stay on my shoulders longer into the run. Oscillations from aggressive running may be transmitted through my shoulders and cause the glider to oscillate. Is that something I need to worry about?
User avatar
By Paul H
#378692
Lean forward as you run and pull the glider with the hang strap and you will have less of a tendency to switch your hand position. Switching to the bottle grip results in you pushing the glider and raising the nose. Ignore the horizon when you're launching. It has nothing to do with setting the proper attitude of the wing. The slope angle and wind or lack of wind on the hill determines that.
Don't fool yourself into believing that a steeper slope gives you a larger margin of error. A steep slope makes things happen more quickly and if your wing isn't controlled properly you can find yourself out of options before you know it.
Last edited by Paul H on Thu Nov 19, 2015 12:12 am, edited 1 time in total.
User avatar
By flybop
#378693
I had some inconsistent launches early on also. The single change that helped me obtain consistent, strong launches was when I began to stay in the grapevine until I am airborne.

The first time was unnerving. It was moments after I saw a friend almost die when launching from a very short, 4 steps max, launch. This launch is actually a cliff launch. My friend popped his nose. I looked up to see him almost vertical when I heard several pilots yell. "Oh sh*t". I remember reaching for my phone thinking I was going to need to dial 911. Thankfully he pulled it out, because of the very steep drop off with jagged rocks below. There has been a fatality there from a blown launch.

I have not gone back since. Having said this, talk to an instructor or qualified mentor before doing this!

Keep on working on being safe! BTW, all the hi-jacking was to impress on you, as well as others, how important this is. Imagine popping your nose during a launch in 20 mph winds. Did you see the "Flip" video?

Be safe and thanks for bringing this subject up.
User avatar
By dave hopkins
#378694
RobertKesselring wrote:
red wrote: Without talking with you first, I would guess that you are looking at the horizon ahead to "set" your Angle of Attack at launch. Forget the horizon, except as a reference for "wings level." The AoA for launch is never set from the horizon. You need to be looking down the slope, and set the AoA from that sight angle, not from the horizon.
Setting my AoA from the horizon is what I was taught at LMFP. From your explanation, it is obvious that is not optimal, but I can see why they teach that way. On a flat slope, setting the nose angle to the horizon is probably just about right. On a steep slope it creates a greater angle between where the glider is pointed and the direction of travel, but steep slopes give you a larger margin for error, so the horizon method gets you closer to the correct AoA in the conditions when it matters the more.

Now that I've recognized that the make-do method that I've used to date is sub-optimal, the next question is...

What do I use instead of the horizon as a reference. I know you said to set my AoA relative to my sight angle down the slope. How high above my sight line would you suggest I set it? Can you suggest any visual cues I could use? Line X up with Y kind of thing?
r p
I am accustomed to having my straps go tight within a step or 2. I'm concerned that a lower AoA may allow the glider to stay on my shoulders longer into the run. Oscillations from aggressive running may be transmitted through my shoulders and cause the glider to oscillate. Is that something I need to worry about?
You have a good idea how to start but we should read every launch. That means accessing the wind and the slope ,gust and switcyness. A glider stalls because of too high an AOA. If we start with our nose too high we are already stalled. If we let the nose pop we may stall after we start.
Look at the slope figure the angle the wind is come up . Set your AOA relative to that. Not that but about 20 degree above that. Slightly lower in stronger winds.
Always be ready to make pitch adjustments during the launch. This is a concept many pilots seem to miss. It's not about just setting our AOA and holding it . Setting it is just a start. We almost always need to Pull-in during the launch . Once we are loaded on the harness straps we should be flying the glider through the launch. We may need to push out or let it out.
My last launch I had to do both. The launch rotor hit me . Even though I was pulled in and had good bar pressure I lost bar pressure half way out the slot :shock: and had to dive a bit then push it out a bit to clear the edge. Launching is about getting the glider flying and flying it through the launch, the flight and the landing. Keep weight shifting until all motion stops.
By old newbie
#378696
Keep the grapevine and save the bottle for the lz. Some manage to switch without popping the nose, but why even try. Launch fly away from the hill and then switch, get in the harness etc.
User avatar
By TjW
#378697
RobertKesselring wrote:
red wrote: Without talking with you first, I would guess that you are looking at the horizon ahead to "set" your Angle of Attack at launch. Forget the horizon, except as a reference for "wings level." The AoA for launch is never set from the horizon. You need to be looking down the slope, and set the AoA from that sight angle, not from the horizon.
Setting my AoA from the horizon is what I was taught at LMFP. From your explanation, it is obvious that is not optimal, but I can see why they teach that way. On a flat slope, setting the nose angle to the horizon is probably just about right. On a steep slope it creates a greater angle between where the glider is pointed and the direction of travel, but steep slopes give you a larger margin for error, so the horizon method gets you closer to the correct AoA in the conditions when it matters the more.

Now that I've recognized that the make-do method that I've used to date is sub-optimal, the next question is...

What do I use instead of the horizon as a reference. I know you said to set my AoA relative to my sight angle down the slope. How high above my sight line would you suggest I set it? Can you suggest any visual cues I could use? Line X up with Y kind of thing?

I am accustomed to having my straps go tight within a step or 2. I'm concerned that a lower AoA may allow the glider to stay on my shoulders longer into the run. Oscillations from aggressive running may be transmitted through my shoulders and cause the glider to oscillate. Is that something I need to worry about?
Either the wind will be blowing parallel to the slope or you will be running down the slope, so the slope, whatever it happens to be at the moment, will be your direction of travel through the air. Your AoA is relative to your direction of travel.

Note that this means that if the hill gets steeper, you have to pull the nose down because if the nose stays at the same angle relative to the horizon, your AoA will increase, just as if you'd popped the nose up.

Consider that with the nose lower, there will be less drag holding you back. You should be able to accelerate faster.
Look at that rotated picture that Red posted. If you saw someone trying to move the glider across the LZ like that, you'd tell them to lower the nose, so they could do it more easily. That's exactly what everyone is telling you to do.

Edited to add:
You're not horrendously off. In that picture, if the nose were lowered to where it just touched the line between the sky and the distant trees, it would look about right to me. Others may have different opinions, of course.