xray328

My Feedback: (1)

It looks like fun and I'm sure its cheaper than glo planes. I just don't understand how it works though. I have a 75' high (or so) sledding hill by my house but I just picture this thing gliding like a paper airplane and having 10 second flights. I flew real gliders a few times so I understand the concept of thermals and all but from 75' I just don't understand how you can take advantage of that. Then I thought that maybe the wind sort of carries it. Ok, but how do you get it back against the wind?

Sorry guys, I'm really confused here.

If theres a thread someone could point me to here I'd appreciate it.

I'd like to build some kind of spad wing like a dazi if someone could get me past the concept of how this works.

[sm=bananahead.gif] <---- feeling like the village idiot.

Liberator

If you have never seen it done then slope soaring is kind of hard to get.
Essentially the readers digest version is that wind blowing against a hill or mountain has to follow the rise of the hill and blow over the top of it. There is a cushion of air that sort of stacks out from the face of the mountain that all moves together over it. When you throw the plane or jump off in a hang glider (assuming your into that kind of thing) you ride that cushion for as long as you want and it holds up.

I have just started back into gliders again and I have not sloped in a long time. But back in the day my longest flight was about an hour before I got nervous about the battery.
That is not long compared to the packs available now. Google up some links on California sloping and you will get a kick out of what type of planes they use.

spritefiend

maybe at the beginning its cheaper than glo, but dont get confused, these things come with some price tags for the composites.

as for slope flying, to keep with the lift from the wind hitting it and directing up your turning into the wind to keep altitude or gain it, for beginners(myself), your pretty much fly figure 8's INTO the wind and across the slope. flaps help a bit ive found especially when turning into the wind so you avoid any sinking or excessive elevator useage which could lead to a stall etc.

im still pretty new so i dont know all the specifics etc, so thats pretty basic

check out this site, good info: http://www.fatlion.com/sailplanes/sailplanes.html << has info on most aspects of it, including slope flying which seems to be what your inquiring about good luck!

John.

Tall Paul

Slope flying is the best way there is to learn how to fly.
You MUST watch what the plane is doing, what the wind is doing, where the plane is relative to the lift, how to get to the lift, get out of it, fly towards yourself, away from yourself, down low, up high.. and without burning any fuel.
You'll never have a problem with the dreaded "DEAD STICK!" ever again, as all flights are dead stick from launch to landing.
My Peck-Polymer's "Genesis" at a local 75 foot slope.

da Rock

Maybe a better description of "how" you can use that 75' slope of yours:

Watch the wind and pick a day the wind is blowing into the slope. The stronger the better but on days with light wind a floater glider works better and on strong wind days a slick, heavy, fast glider is better.

You launch by throwing the glider straight into the wind, pointed straight out, not up at all. But once you've got control and the glider is settled down, turn and fly along the slope. When you run out of slope in that direction, turn the glider away from the slope and bring it back going in the opposite direction. You won't need to be very far out from the slope and won't need to be very far up either.

You can go back and forth all day.... or until the wind quits or shifts. But that often gets boring so if the a/c matches the conditions you can also point her out perpendicular to the face and match your airspeed to the wind speed. And do aerobatics all day long. Don't have to sweat running out of fuel.

There are lots of very fun puzzles in glidering. Like, did you know that most rudder/elevator gliders (the ones that DON'T have ailerons) can do really decent "aileron rolls" on a slope? And to me, the most fun puzzle was "how do I tell when I'm running out of battery"? And that question comes up almost every time I went sloping.

Sloping is about the best way to R/C there is. You choose if you want to lay back in the lawn chair (alway ALWAYS take a lounger to the slopes) and just hang her out there, or if you want to stand (leaning into that Nor'easter) up, grit yer' teeth and BEND HER WINGS some!!! Kewl way to fly.

CHassan

My Feedback: (13)

Speaking of hang gliding, Kind of hard to see, but that is me and my hang glider in my avitar.

Any kind of soaring is based on the same things. Rising air, be it thermalls or ridge lift. I fly off of a 400' hill and have managed an hour long flight. The vetrans can fly for as long as the lift continues.

I also fly off of a scooter tow (honda 250cc Helix scooter made into a winch system). This acts just like a winch or highstart for the RC gliders. It is a pretty radical climb out for a hang glider. I've managed just under an hour and climbed to over 3 times my release alititude. Agian the more experienced pilots can stay up much longer.

The thrid and final way I launch my glider is by aerotowing it. Just like the full size sailplanes, and some RC gliders. This is the prefered methode, but not always available. The top pilots can fly for 10 hours and over 300miles
Check out this link
www.hsl.org.au/articles/slopes.pdf

gtmattz

Nobody has mentioned hi-starts and winches. this description of a hi-start I found pretty much sums it up:

"It is simply 30 meters of 8mm surgical tubing with 125 meters of string attached. You nail the end of the surgical tubing to the ground and stretch it out to about 100 meters. Attach the string to the towhook on the bottom of your plane and throw the plane. The tubing acts like a big rubber band and pulls the plane into the air. Launch height is 50 - 200 meters depending on the wind."

A winch is essentially a motorised version of the above, a bit more complicated to use however, the details of which, I cannot give as I have never launched off a winch.

da Rock

Your bungee (high start) description is a good one, but it left out the parachute.

You got your spike with one end of the rubber hooked to it. The other end of the rubber is tied to a cord. At the other end of the cord is a small parachute. At the very top of the chute's canopy is a steel ring. You hook your glider's tow hook on the ring and start walking downwind. As the system tightens up, it pulls the chute closed. As long as the system in under tension the chute stays closed. When you pop off at the top on launch, the chute cracks open and floats downwind. It's a great system. Not only does the chute pull the cord back toward where you're going to launch from, it brings the tow ring with it. And it's also a great wind direction indicator.

So how does a winch work? You put the winch about where you are going to launch from. It's got a big drum of cord. No rubber. You've got a pulley that has the spike attached. You walk into the wind carrying the pulley and the end of the cord. There also happens to be a chute on the end of the winch cord. When you get WAY out there, you stick the spike in the ground and thread the cord through the pulley and start back to the winch. The end of the cord will have the chute/ring on it and you're pulling that along with you. As you do, you can hear the winch whining as it lets out cord. When you get back to the winch, very often YOU get the first launch since you did all the work. Truth is, everyone has suckered you into doing all the work and now they want you to be the test pilot to see if the pulley is placed right and if it's snagged on something and is gonna dump YOUR glider. You hook your glider on the tow ring and........ the winch has a foot switch. You put your foot on it and blip a couple of times to see if the cord is moving on the pulley (that's way off up wind) and if the cord is snagged on anything. You blip a couple more times to pull the cord tight and load the system. Right about now, the wind will shift and the pulley won't be directly up wind anymore!!! You got your glider in one hand and the tx in the other and the pull in the system is trying to move you up wind, toward the pulley. You "throw" the glider and blip the switch and GONE!!!!!

If you're launching a large glider the winch might be struggling. You'll probably have to stay on the switch until your bird tops out. With 2meters and small, slick gliders you only blip the switch as little as possible. The idea is to run the winch as little as possible to get the highest launch possible. You fly the glider all the while trying to use it to keep the line "long". If you're really good, and maybe have some wind in your face, you can actually pull out cord on the winch by flying your glider "hard" and launch higher than the distance to the spike.

Winch's actually are pretty scary lumps. They can put a world of hurt on ya' in a number of ways. But for big gliders they're the nuts.

And then there's "tow" launching. There are a couple of ways to do that. Next month's issue will cover that topic.

wind junkie

My Feedback: (1)

Here's another great site :

www.slopeflyer.com

Tall Paul

With a bungee or a winch on a calm day, you get a lot of landing practice.. and learn to finesse the landings to occur near where the towring came down..
Minimizes the walking.. and increases one's situational awareness.

JasonS

Slope soaring is kinda like surfing on an ocean of air. And its a lot easier to find wind than a shoreline.
And you will find that many "thermal" sites have some slope lift. All it takes is a few trees.
I'm always amazed to hear local glow pilots claim you can't slope around here. (midwest) I've logged 4 hour flights flying off of a small 40 ft. dam face on a man made lake. Could have stayed up all day if my batteries were up to it.
If you can get used to landing in ground turbulence, you can slope almost anywhere. I sloped the backside of a Walmart building for 2 hours during an extended lunch break once.
Its kinda liberating to learn to keep a plane up with no power at all.

Check out some of the videos from Radio Carbon Art to really get an idea of what a "glider" can do.

xray328

My Feedback: (1)

Hey, so just to get my feet wet here...

Could I buy one of those $3 foam toy gliders from the LHS, make the control surfaces functional and bungee it up there?

It might be a cheap (and safe) way to teach my 5y/o how to fly.

It also sounds like a good alternative for me to get my flying fix. I was flying parkflyers becuase of the convenience of being able to fly at the park 2 blocks away. Trouble with that though was that in 10mph winds I had no control. So I moved up to glo planes to get past the wind factor. But now I can't fly at the park anymore. [:@]

The slope flying sounds like a nice challenge though. Just sounds like theres a bit of a learning curve to it.

If I use the bungee method, what angle do I launch at? Is it just a matter of trying it and seeing what works?

Where could you attach a bungee cord on a foam glider that could withstand that kind of force?

da Rock

The problem with taking a little foamy and trying to hi-start it is in the wing. Any launch method other than test gliding by hand stresses the wing tremendously more than that wing is ever going to see when the glider is just sailing around. Foamy wings probably aren't going to hack it no matter what you do to reinforce them if you plan to learn how to hi-start with them. A very talented glider pilot who is really talented at steering a glider on launch probably would wind up blowing the wings off a foamy every time he went flying with one, maybe not on the first or second launch, but it'd happen.

The angle you use is sorta dependent on the weight of the glider versus it's wing lift capability versus the overall strength of the hi-start versus how hard/far back you've pulled the hi-start. But a simple suggestion is to just make sure the nose of the glider isn't pointed down. What happens is that VERY SOON after you let go the glider's own pitch stability comes into play and starts to sort it's pitch out according to this massive, artificial gravity that's PULLING at the towhook and according to it's "aerodynamic center". So it's going to almost instantly start sorting itself out. If you've launched with too high a nose that won't be too bad. If you've launched with too much down angle, the sucker is going to get some airspeed in a heartbeat and then start to zoom up. And if it's wings can take it......

The way you learn to launch is gently.

Walk the plane back until the bungee is pulling SOME. Aim the nose up a little and let go. (Make sure the empennage is higher than the back of your head. Or just make sure the whole a/c is above your head.) You'll get a really good test glide. You didn't waste any time because you got to see what the glider does at a faster speed than you get throwing the sucker into it's test glides. Next launch you'll have a better idea of where the wind is coming from and how the glider is trimmed so.... Walk the next launch back until the bungee is pulling SOME MORE. etc

As for where to put the tow hook..... On a foamy, the problem isn't with attaching the tow hook so IT won't pull out. But on any model glider, the location of the tow hook is usually referenced to the location of the CG of the glider (because the aero center isn't readily found or easy to "put your finger on" like the CG is) and all that's a chapter by itself. Best bet is to do some searching and read.

BTW, you can work out an appropriate bungee for a foamy. But you're not going to be using anything like any of the conventional rubber that's sold for existing glider bungees, and there used to be some really small rubber sold for "small field" sized models. I'd say the design considerations for your foamy would be: First consideration is you want to get the sucker up as high as possible, but that's probably only going to be a couple of stories up. Second consideration is the rubber has to be weak enough not to trash the airframe. That'd probably mean using some rubber bands, cut once to become "rubber strings", tied together end to end. Another (somewhat specialized) possibility is free flight rubber. It's sold in LHSs on spools. Third consideration is easy. Kite string. Fourth consideration would be the chute/ring. Forget the chute unless you can make something tiny. Just go with a very small ring and deal with finding the end of the thing wherever it falls. But put a section of bright ribbon or somesuch where the chute usually is positioned.

You know, I got some pink foam in the basement and some kite string and....... chuckle..... and there's that boarded up grocery store's parking lot that always looks like it's pumping out thermals..... chuckle.....

CHassan

My Feedback: (13)

Lost my first gentle lady due a helper who let the stab hit the back of his head. After that it was just pure destruction, as it hit the ground and was drug through the dirt for 70 yards or so. I didn't even bother picking up enough pcs to start a fire with.

As far as a foam glider to withstand a highstart launch, doubt there is one. If there is it wouldn't be cheap.
You could get the foam ones and launch from a hill though.

xray328

My Feedback: (1)

Could you poly the wing?

CHassan

My Feedback: (13)

If you were to sheet it and such it would be fine, but then whats the use of getting a cheap foam model and working so hard to make it usable, when you can spend a little extra cash and get something you know will work.

Oh one other type is the discus launched gliders. These have a peg in one wing that you use to "throw" in the air. Kind of the same way you would throw a discus. (hence the name)

da Rock

I doubt it too. But when I mentioned the foam in the basement, I had some ideas that might just be outside the box, and most assuredly outside the RTF boxes, the ARF boxes, and all the kit boxes I've seen. The plan would be to find the appropriate size rubber to use to tie up a "micro" bungee. Like, 20' of FF rubber? or somesuch. Something milder than the small field hi-starts that're being sold today is the plan. And then the glider designing/evolving could conceivably start with a wing made from the 3/4" thick foam sheet but with say a vertical spar. And a couple of nano servos??? And the target a/c would be for flying off the big abandoned K-Mart parking lot that's across from where I used to work. I wasn't really thinking about, even considering actually, the flat-foamy kind of wing, nor the bare white beercooler foam type wing either. Figure the right spar design.... and maybe, maybe a top covering of carbon veil.... but hopefully the veil wouldn't be needed? but who knows until they try.

The design problem would be two fold. The highstart would have to be just weak enough and the wing just strong enough.

And I've seen that parking lot pump thermals that lifted foam cups etc.....

CHassan

My Feedback: (13)

I'm sure you could create a glider/highstart combo that would work for a plain foam wing. Heck some fishing line and a small electric motor and you could create a "micro light" winch. You could probably make it so the foam wing would be strong enough with nothing more than a light balsa spar.
That would be good for parking lot soaring.... I actually find that very tempting.

mmartin55

Hey foam airplanes work just fine on histarts or winches or aerotowing.

Look at the Daves Aircraft Works web site or Skyking or Leading Edge Gliders or Ishtmus Models. Just about any of these kits properly built is capabable of a zooming winch or histart launch. Most are over-engineered in the spar to withstand highspeed maneuevers and aerobatics on the slope and even flying the rotor on the backside of the slope with speeds well in excess of 100 mph. The worlds record for speed of an RC aircraft is held by a glider and probably always will be. Their ability to launch in this way is only limited to the ability of the pilot and good solid construction.

That surfing analogy doesn't even do justice to the energy and forces generated by wind rising up the face of the hill and cresting over it in a massive curl.

Tom

mucksmear

Hi xray328,
In a nutshell, this is how slope soarers are able to stay aloft at a slope site:

As you have thermaled, you already know that what enables your glider to gain altitude in a thermal is the simple fact that the air in the thermal is rising at a rate that is faster than the sink rate of your glider, hence your glider will rise in the thermal, at a rate equal to the thermals rate of rise minus the sink rate of your glider.

When slope soaring, air approaches (a common condition known as wind!) the slope of a hill (mountain, ridge, cliff, etc.) and rises up the slope, over the top of the hill and then down the back side of the hill. If the air that is rising up the slope is rising faster than the sink rate of your glider, then your glider will climb!

Next, as you already know from flying any sort of airplane, when you point the nose down, your sink rate increase and your airspeed increase. So as long as the air mass is rising up the slope at a rate that is higher than the sink rate of your glider, you can point the nose down a bit and increase your airspeed, without losing altitude. That's how the glider can fly upwind or "penetrate" as it's often called.

Generally we fly on the up-wind side of the hill for the above mentioned reasons. The down-wind side of the hill is often treacherous as the air is often very turbulent and unpredictable as it descends down the backside.

Some hills will produce more lift than wind (these are the ones we like), while other hills will produce more wind than lift (slope may be too gentle).

Also, tree lines, hills, buildings or other large obstructions that exist upwind from your slope may or may not disturb the air mass enough to cause turbulence at your slope site. Ocean sites are often ideal for this reason.

Hope this clarifys the basics and good luck with the 75' hill!

Tall Paul

A short sloping video:
http://media.putfile.com/ZigginwZAGI
The slope being used is maybe 70 feet.. it's at the end of the downhill from where Freeway 14 comes over the pass into the Antelope Valley.
At the top of the pass is where the dynamic soaring world record speeds are set...

BMatthews

I made up just the thing you're describing here a few years back to launch my javelin style RCHLG for after my arm got tired. A single loop of 1/4 flat rubber about 20 feet long and 80 feet of 10lb test mono filament and a little 6 inch sq flag of light ripstop nylon instead of a chute. It pulled up my 12 ounce 50 inch span model into a 2 or 3 mph headwind like a champ and even had enough left over at the top to "ping" the release for an additional 6 or 8 feet of height. In dead air it will lift most of the rubber off the ground just before the model drifts off the hook at the top. All that on what feels like about 1 to 1.5 lbs of pull at max.

I suspect something similar would work for the $5 foamie with RC in it as well. At worst you may need to add a "spar" of fiber tape on the lower side to help resist the awsome pull of this lilliputian monster high start.

As far as teaching the boys to fly on the slope that may prove more difficult. Slopes often have a lot of turbulence in close and sometimes further out as well. They also require you to work with the terrain and wind and that requires some judgement during flight that won't be there in a young beginner. Start them on calm flatland days and work them up to the slope thing.

But when slope works and you are comfy with using the slope and know to avoid the bad pockets and stuff it's GREAT fun. I just wish we had a decent slope around here with road access and fewer trees. Lots of mountains and slopes but they are all either too rocky to climb or loaded with trees so there's no where to launch and land.