airplanes and sailboats

[Simon]

So I work behind a bar and i spend a lot of time explaining to people what paragliding is. Most of the time I do not talk to people long enough to paint a good enough picture for them, so now I just tell people I am a hang glider pilot. I flew hang gliders with Tammy Burcar on two separate days before taking on the art that is paragliding. Both sports are two separate beasts, and hang gliding makes a lot more sense in terms of how you fly than does paragliding.

I still want to take up hang gliding eventually, am waiting until I have enough money to afford it and have a truck that is good for doing that and retrieving (F-250, Diesel, 4x4, long bed, camper shell, and ladder rack). Anywho, I have had the benefit of having taken flying lessons in a Cessna 150 and sailing a 16' sailboat with a centerboard way back when I was a younger person, and there is a couple maneuvers I learned back then that I use every time I fly, subconsciously. The maneuver with the sailboat is simply that a sailboat cannot penetrate the wind by pointing the boat directly into the wind. This has to apply to paragliding. The more I think about my landing near the river bottom after flying the Nuthouse, the more appreciative I not pointing my wing straight into the wind and waiting til my feet touch the ground. I have control of relative wind on my wing so long as I am pointed at any given angle into the wind. For those of you who are familiar with sailboats, I know you are familiar with how the sail on the boat works and what it takes to sail upwind. Now I do not have a formula in front of me for calculating how that relates to paragliding, I do know there is some kind of relationship. Being pointed into the wind means you have fluctuating amount of forward momentum determined the character of the air you are in, where as if you are off center, your momentum is not determined by the velocity of the wind solely.

Comparing a paraglider to an airplane is very difficult, what I do that is similar to an airplane is a maneuver called a "side slip." Ben H knows what this is because he has to use one almost every single time he lands the Citabria at the flight school he goes to. This maneuver is a combination of pitch, yaw, and roll inputs all being done at the same time. For a paraglider this means maintaining a heading while giving opposing yaw and roll inputs, the only way to control pitch on a paraglider is a combination of velocity (or momentum) and break pressure. Roll and yaw control is done using weight shift and the brake ailerons. I like to think yaw is accomplished using weight shift and roll involves applying brake on one side or the other.

Any other thoughts on this?

[andy]

Hey Simon, My thought on most of your posts is "take the cotton out of your ears and put it in your mouth" or as the case may be your keyboard.

What you say is completely wrong and I have a broken back to prove it.

Try flying more and commentating less.

Andy

[Simon]

Got to hand it to you Andy, that is one of the most insulting thing anyone has ever said to me. If you really wanted be hurtful, you could use the Bible; here is a good passage, Job 13:5, "If only you would be altogether silent! For you, that would be wisdom." But no worries, Tom Truax Jr. is made of steel.

And so last night i was having a bit of insomnia and so i picked up my favorite book, the 2002 Federal Aviation Regulation, and i turned to my favorite part, 91.3 Responsibility and authority of the pilot in command. Section a and b are the only relevant parts to this conversation.

(a) The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.
(b) In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency

Flying is a very visceral experience, be it hang gliding or paragliding. What takes place in the air is different than what happens when you are simply watching someone fly. I do not paraglide unless i have a clear head. If my girlfriend is mad at me for something and I do not know what that something is, then i am not going to fly because I cannot have that haunting me when I need to make instinctual decisions to maintain my airborne survival. I enjoy proposing thoughts on flying theories that provoke more thought in the process, while maintaining a lightheartedness about suggesting these ideas. Ignore everything I say in the General Forum if you like, I will keep the description of my flights in the Flight Discussion Forum.

[Parma Chris]

<<Grabs a bucket of popcorn>>

[Don F]

[Chris G]

Well, I'm not sure what all the interpersonal politics are about but if anyone wants me to take some action, I will.

Simon: As far as your original question is concerned. I think the difference is that the relative wind on your glider is always the same, whether you're pointed directly into the wind, or not. Sure, it may change a very tiny bit depending on your AoA but that's a vertical change, not a horizontal change. You can test it sometime by tying a streamer to one of your lines, or your big toe, or anything out in the airflow. So, that being said, the fastest way into the wind, is directly into it. Tacking across the wind will slow your progress upwind considerably because a component of your forward speed will be toward your target, and a component of your progress will be downwind. When pointed directly into the wind, your directional vectors are combined. Think about swimming in a large river. Swimming across the river will eventually put you downstream. The only way to make the best progress up-river is to swim straight up it.

I'm a little tired so that may not have made total sense. I just rolled into Georgia after 4 days on the road. It's probably a discussion better suited to a whiteboard and some drawings anyway.

[Leeside]

Well with all this weather we have currently at least this thread is entertaining. Simon- When I first read your starting post It did seem a little like "check out what I know" kind of. And knowing Andy well I see his response as a coarse way of saying 'put down the pipe for a minute and read some actual aviation books rather than daydreaming flight theories like some early 70's hangliding hippie'. Andy does know what he is talking about but has less patience than some. I actually got a good laugh at his response I guess at your expense, sorry. Concerning your post though I applaud you for putting it out here in a public discussion and all so do continue to daydream. The main problem issue I had originally beside the flight theories is that LAME excuse you use for not hangliding because you lack a monster truck currently. I have seen many small cars (escort) used to transport hangliders so that excuse will not work. Your idea of flying off the center of the wind line may seem like a benefit in maintaining inertia but myself and most others would disagree. (who really is an expert anyway? we need that Mark Stucky guy to chime in here.) The only SIMILAR theory I have heard of from experienced airplane pilots is that dealing with severe windshear at an airport. If other aircraft are reporting airspeed deviations of say +/- 20 knots or more on final, and diverting to another area was not possible, it would seem landing on a crossing runway with a large gusty crosswind may be preferred to a direct headwind with a possible loss of 20 knots airspeed on short final. Again it depends on who you ask. As for your ability to do a side slip with your bag you really are dreaming. You need a rudder to cross control an aircraft. Oh and Simon if you ever quote the FAR's on this site again you may be banned or I'm going to puke or maybe both. Its your favorite book?....Really? Just kidding! Keep those comments coming Simon and I hope to see you in the air soon.

[Parma Chris]

<<runs out to grab another soda - brb>>

[Don F]

Simon, I think that the unwritten laws of nickname acquisition prohibit self imposed monikers. Therefore, the TT Jr. thing is invalid.

Remainder of post deleted due to temporary insanity.

[Dirtfoot]

P.S. Simon, I think that the unwritten laws of nickname acquisition prohibit self imposed monikers. Therefore, the TT Jr. thing is invalid.

Agreed. Having flown down in really lousy conditions instead of risking the ride down in the "vehicle" Tom was driving (ever felt like an air hockey puck??), I'm confident Sundowner would never let lack of a monster 4x4 stop his adventures.

The best nicknames are bestowed upon you by your friends when you've performed some memorable stunt(unlike mine). I've reciently discovered the master at this is Kabir (means "the magnificent" in certain foriegn contries). I'd suggest you spend a few weeks flying with him, and you'll be set up with a real nickname that even Kristen will like.

As for Andy, don't get too excited. Next time you land out and he comes to rescue you, you can buy him a beer. Then make him buy you one for his post, then you buy him one, etc., etc. Pretty soon neither of you will remember what that second beer was for anyway...

[Kristyn]

I would really like andy to elaborate on why simon is wrong. i find it helpful to learn from others mistakes. I think I might understand Chris's thoughts, but it seems to me the shape of the wing would also have an effect. simon's theory would only make sense to me in situations where there is a constant airflow. I have yet to land in a place with a consistent and steady flow. fun conversation. Parma, I’ve got the sour bears, wanna share some popcorn?

simon does have a nickname, it has something to do with him being a childhood champion horse back rider, and he has the belt buckle to prove it

-kristyn

[Simon]

No hard feelings, Andy, I am glad you drew so much attention to my post. My moniker, TT Jr., was just a tool to make this interesting, all my friends call me Chuck Norris.

Now I am going to disagree with what Chris said about swimming upstream, you can cover more ground by not swimming directly up stream. When I am scratching hard, I am traveling across the face of the mountain while keeping my glider pointed into the wind. Depending on the direction and strength of the wind, I will keep my glider turned to get the best glide and as little sink as possible. Now thermal flying, of which I have very little experience, entails going from one mysterious thermal to the next, covering the greatest amount of distance while pursuing a goal is important. If you are fighting the wind to get to where you know the next thermal is, turn one degree off of directly upwind, I theorize, will move the pilot a little quicker even though the flight path is not as direct. A sailboat sails upwind, it does it by tacking, otherwise the boat will be blown backwards. The angle of attack of the wing horizontally is very important, I am under the impression the angle of attack vertically is not being accounted for. The curve of the paraglider wing gives it stability and it also gives it a horizontal, vertical, and every direction inbetween wing profile; there is a relevance to which direction the wing is pointed especially when it is into the wind.

Feel free to laugh at my expense, but know this, when Chuck Norris does push ups, I am not pushing myself up, I am pushing the world down.

[gary begley]

Chuck Norris' tears cure cancer. Too bad he has never cried.

[Chris G]

Yes, you may be covering more ground by not pushing directly up wind, but your VMG (Velocity Made Good) toward your goal will be slower. You have to differentiate between speed in any direction, and speed toward your goal. I'll go back to the stream analogy. You want to make it to a goal upstream (your LZ). The stream is moving at 10mph and you can swim at 20. Now, swim directly across the stream. You will be moving across and through the water at 20 mph, but you will also be moving downstream at 10mph. You've made negative progress toward your goal. Now, go back to your original start point and swim at a 45º angle across and upstream. You will now be making 4mph progress upstream, and 14mph across the stream (assuming I'm reading my E6-B right which is by no means guaranteed but you'll see where I'm going in a second). Now, go back to your original start point and swim directly upstream. Simple math, airspeed-groundspeed=progress so you'd be doing 10mph upstream and 0mph across the stream. The farther upstream you point, the better you'll do when trying to make progress to your LZ. You went from -10mph at 90º, to +4mph at 45º, to +10mph at 0º.

Now, that being said, there are certainly circumstances where flying directly upwind will not get you to your goal as effectively as going around the long way. It doesn't have anything to do with tacking across the wind though. Take Chief's for example. If you leave launch and fly directly to the LZ you're flying over a canyon full of sink and wind. More than one person has made that mistake. By going around the long way and flying down to twin peaks before heading out you avoid the valley winds and draw up the canyons. Same would be true for flying Nordhoff. If you leave from Bruce's and go on a straight glide to the HS, you probably won't make it because you'll be flying directly into the wind. By moving down the ridge before heading out you aren't taking as much of a headwind component and are more likely to make the LZ. It's all about vectors.

If you're still not convinced, hit a ridge site. Point your glider directly down the ridge and watch your sideways drift downwind. Now progressively point yourself further upwind. Your drift will pass through 0 before becoming positive, and at straight upwind you will be making the best progress toward the beach/LZ.

BTW, if you have a Garmin GPS it should have a field for VMG. Plug in a waypoint as a GoTo and try different angles. It'll show you how fast you're making progress toward that point, not your actual groundspeed.

[Southside]

I know nothing about sailing, but I think the difference is the sailboat's keel and how it pushes against the water.