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Oz Report

topic: electric (16 articles)

Electric powered flight »

Thu, Jul 14 2022, 6:29:43 pm GMT

Charles Allen|electric|power|video

1st flight with upgraded XTM unit. Results were awesome. Unfortunately I had a bad connection on one of the wires from the ESC to the left motor so lost one motor after a few minutes. On a positive side the ESC, motors, battery, and props are all sized right. Next step is add a mouth throttle so I don't have to let go of bar to turn motors on. Plan to move to a mesh network between power unit, mouth throttle, and down tube controller. With a mesh I should have software infrastructure to quickly integrate an epowered cart for flat land launching. Also plan to move to CF props and prop holders which should reduce weight by 1lb overall.

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Vortex Smartwinch »

Tue, Mar 22 2022, 8:33:37 pm MDT

At Wilotree Park

electric|winch

https://instinct.pro/collections/vortex/products/the-vortex-smartwinch

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Swift Competition

Fri, Mar 4 2022, 10:30:48 am MST

2022 Class 2 (Swift) World Championship

aerotow|competition|electric|FAI|FFVL|Michel Paté|Swift|Worlds 2022 Class 2 (Swift)

"Michel Paté" «michel.pate» writes:

Due to the success of the 2017 edition, the FAI (Fédération Aéronautique International) has awarded the organisation of the prestigious 21th World Championship for Hang-Gliders Class 2 to the FFVL (Fédération Française de Vol Libre) together with ADPUL.

This World Championship will take place on Aspres sur Buëch airfield, in the french Southern Alps, from July 23rd to August 6th 2022.

This event will be exceptional, as it will be the first FAI World Championship to accept Class 2 hang gliders equipped with an electric launch device. So aero-tow and electric motor self-launching will be allowed for the competition.

An opportunity for worldwide Hang Gliding Class 2 pilots to meet, fly and have fun all together in this amazing region.

All detailed information about the competition and registration process HERE

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Looking for Archaeopteryx

Thu, Dec 30 2021, 6:09:38 pm MST

Got one for sale?

Archaeopteryx|COVID|electric|James Yeomans

«James D. Yeomans» writes:

I spend summers flying my ASH31mi out of Minden and have been flying in Omarama during the winter until Covid intervened. I’m considering moving back to Guam from Hawaii and the electric Archaeopteryx would be perfect to fly there.

Unfortunately, there is a 1.5 year wait for delivery of a new one and who knows if I will even be able to fly by then. I plan to fly theirs in Wald this summer. Perhaps someone wants to sell a used one? I think they have made only 35 in the last 10 yrs. <archaeopteryx.ch> If so, please contact me.

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Constant tension electric winch

Tue, Nov 2 2021, 11:42:49 pm MDT

The Vortex SmartWinch

electric|Instinct Windsports|Mark Dowsett|Nick Jones|Ryan Wood|safety|scooter tow|stationary winch|tandem|tow|Vortex SmartWinch

https://instinct.pro/collections/vortex

We are ready to announce this exciting project we have been working on all this season - we are manufacturing the first commercially-available all-electric hang gliding stationary winch!

We feel it could be quite revolutionary in the industry. The power is there to even tow tandem hang gliders. The intelligence is there to automate the winch operator's job to make it easy for new winch operators to increase your flying communities number of flights.

AND, the foundation is there for us to implement remote-control winch operating - imagine being able to tow yourself up where you want, when you want… all with no need for crew to assist you!

The key feature is the torque-regulated abilities… you just dial in the desired max tow tension and the winch moderates the speed the drum turns to automatically adjust to give the pilot a constant tow pressure, regardless of hitting a wind gust, thermals or sink while on tow.

It is also incredibly portable! There are three components - the motor/drum, the controller box and the battery. All are light enough that they can be taken in and out of an SUV trunk and mounted on your trailer hitch as desired. No storing an entire trailer somewhere - take your winch home and go out to fly where the conditions are prime - rather than relying on a dedicated club site.

We will be taking pre-orders right away with hopes of spring 2022 delivery. We have flight tested the prototype to our satisfaction but are making some alterations for the final configuration. Prices aren't finalized yet but are working on some accurate ball-park figures. As we add features and improve some components, the prices will only go up from what we have listed.

https://instinct.pro/collections/vortex/products/the-vortex-smartwinch

The Vortex is a tension-controlled winch. This is opposed to a speed-controlled (or throttle-controlled) winch.

A speed-controlled winch puts a great amount of responsibility on the winch operator. If they only have speed control, they have some work to do to manage the tension on the tow line throughout the tow.

Some hydraulic winches are smoother but hydro-static winches still require the winch operator to visibly monitor a pressure gauge and adjust their hydraulic flow to attain and maintain a desired tow tension. And the tension can and will change throughout the tow due to glider speed changes, lift/sink, wind gusts and thermals. With a tension-controlled winch, the intelligence of the winch takes care of all that… resulting in a much smoother tow and way more efficient with increased safety.

Scooter winches are notorious for rough tows. All you have is a gas throttle to adjust and most scooter-winches don't have a pressure gauge to monitor. This requires an even more skilled winch operator and often a very rough ride. For this reason, scooter winches are usually only used in low, smooth winds for rather low-tension training tows.

There are also winches based on the LSD (Limited Slip Differential) transmission of a car. These are strictly gas throttle controlled as well and have the same problems as a scooter. They do have the added feature of setting a max tension that the transmission will slip if that max tension is attained to limit the tow from going over the max tension. This adjustment is very hard to set and calibrate as you have to test manually with a gauge and is often set way too high.

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ATOS trike

Mon, Dec 3 2018, 8:00:59 am CST

Electric engine also

electric|trike

https://www.facebook.com/groups/436449473535787/permalink/505270189987048/

6,000 Euros for the non-powered version of the pod.

Electric general aviation plane

June 23, 2016, 6:13:42 MST -0600

Electric general aviation plane

NASA development work

electric|NASA

http://www.nytimes.com/2016/06/18/science/nasa-electric-plane-x57.html

The X-57 will look more like a Cessna, unlike some of NASA’s earlier sleek, futuristic X-planes. Its cruising speed might hit 175 miles per hour. Its wings, however, will be unique — far skinnier than usual and embedded with 14 motors.

First electric flight season

November 6, 2014, 4:43:40 pm PST

First electric flight season

A launching motor

electric

http://www.ruppert-composite.ch/en/aktuell/256-elektroflugsaison-die-bilder.html

Multiple images.

ATOS trike

Mon, Oct 1 2012, 9:49:12 am MDT

Electrical

Aeronautic Innovation Rühle & Co GmbH|electric|trike

http://www.a-i-r.de/ger/air_02.php?kat=118&par=0&gp=2

Electric Scooter Tow at Quest Air, the cart

Fri, Oct 22 2010, 9:48:31 am PDT

A few pictures

cart|electric|Mitchell "Mitch" Shipley|Quest Air|scooter tow

Mitchell Shipley «Mitchell Shipley» sends:

Another use for the electric drive train

Fri, Mar 5 2010, 8:37:36 am EST

Personal aircraft

electric

http://www.physorg.com/news183361139.html

NASA engineers have designed an extremely quiet one-person electrically powered aircraft that can hover like a helicopter and fly like a plane. The “Puffin” launches from an upright position with the tail split into four legs that serve as stable landing/take-off gear.

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Varios in sailplanes

Sun, Jun 15 2003, 2:03:01 pm EDT

battery|electric|GPS|Mike Ziaskas|sailplane

Mike Ziaskas <Mzsoar@aol.com> writes:

I've been using my Brauniger IQ comp connected to GPS in my sailplane (Apis) and find it works great. You can't use the airspeed function for obvious reasons, but the Brauniger gives you GPS ground speed and also calculates wind direction & wind speed when thermaling.

I use it in conjunction with a compensated electric sailplane vario. I haven't figured out how to use the two varios to an advantage (compensated with non-compensated) but it's nice to have two audio varios.

(battery went dead on the sailplane vario & thus the faulty reading).

Discuss varios at OzReport.com/forum/phpBB2

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Aerotow paragliders

Sun, Jun 1 2003, 2:03:03 pm EDT

aerotow|altitude|bridle|David "Dave" Glover|David Glover|drogue|electric|government|harness|job|Lighthawk|Mark "Forger" Stucky|Oz Report|payout winch|PG|power|powered|powered PG|PPG|Quest Air|sailplane|Stuart Caruk|Stu Smith|tail|technique|tow|towing|trike|tug|winch

Mark Stucky <stucky_mark@hotmail.com> writes:

I just noticed the discussion on the bigair paragliding forum regarding the recent paraglider aerotowing shown on the Oz Report. For several years I've occasionally put thought into the conceptual design for aerotowing a paraglider. I really think the future is in aerotow and discussed the issues some with David Glover (who is also very interested in it for big meets) last September at the Tehachapi sailplane fly-in. I wish we could have talked more but most of my attention at the time was dedicated to the Lighthawk flying debut.

The obvious issues with aerotowing are the slow flying speed of a paraglider and the relatively small amount of pitch and airspeed control available. Some comments on the web about concerns with the vertical distance of the canopy from the tow point are not that big of a deal due to the low thrust and drag forces involved. After all, if a paraglider couldn't handle 80 lbs of thrust near the CG of the pilot then powered paragliders would not work either!

I see three methods for aerotowing a paraglider.

Method 1: The obvious solution is a tug that tows at a compatible speed and climb rate. This method would involve conventional "follow the tug" procedures and a fixed length of towline. While having a PPG or powered PG trike arrangement has some appeal due to their slow flying speeds, I think they will cause more problems than they solve. I think a better tug would be a fancily flapped ultralight or a very large yet lightweight hang glider trike. Until such an exotic tug is designed we will have to make due with exotic procedures.

Method 2: Perhaps the best solution for paraglider aerotowing is to make a lightweight payout winch that can handle 2500 feet of spectra. Until we can get the tow airspeed slow enough to match the speed the paraglider pilot would like we will need to figure out how to handle a speed differential. With a payout winch you could use existing tug aircraft with procedures similar to a ground payout winch tow, the paraglider could simply climb up behind the tug without regard to maintaining the same relative altitude as the tug.

Let's assume we can get a tug that can tow at 45 feet/sec (30 mph) and have a paraglider that wants to fly at 30 fps (20 mph) for a differential speed of 15fps. I think a comfortable climb rate for a paraglider from a ground tows is 500 fpm. If the tug was also climbing at 500 fpm then the total climb rate of the paraglider would be 1000 fpm so a two minute tow to 2000 feet AGL would require 1800 feet of tow line (plus whatever amount you initially laid out). The benefit of an aerotow winch would be that you could use a small field and any wind direction instead of being tied to a long road.

Additionally, the tug could tow you to a thermal although once the line pays out beyond a few hundred feet the tug will be limited to shallow banks or short, quick turns (similar to ground circuit towing). The winch would have to have some kind of rewind capability and a small drogue to ensure it couldn't recoil into the tug's propeller.

Method 3 is obviously not for the faint of heart and requires advanced skills at both ends of the towrope. It is designed to make due with existing tow aircraft and uses a small fishing reel as a short duration payout winch. One way to manage a small speed differential is by using differential bank angles to fly concentric arcs with the paraglider flying a slower speed on the inside of the turn.

Stu Caruk's comments about delivering a bag of goods from a Cessna by hanging it out a window and flying circles around it has some merit. I was once involved in a government program that built upon that technique in an attempt to hover a small spy package several feet off the ground. The package contained sensors and fed position and altitude information back to the aircraft that was equipped with an exotic hydraulic winch which would make the fine high speed in/out corrections to the tow line while the pilot make the rough corrections by following guidance to fly an exact arc thousands of feet overhead. The program got cancelled and I sure wish I could have figured out a way to get my hands on the winch and the 10,000 feet of spectra!

To tow successfully without a high capacity payout winch, we need to manage not just the airspeed but also the climb rate, turn rate, and rope length. To manage the rope you need to first start with the proper length of towline. Too short of a rope and the workload is too high, the allowable lateral/vertical errors too small, and the probability of a lockout is too high. If the rope is too long then the turn circles are no longer concentric and havoc will quickly result.

We need to fly the proper arcs at an angle of bank that does not require extraordinary piloting skills or decrease the climb rate excessively. This means we need shallow bank angles so we can increase or decrease them as required without generating excessive turn rates that would be impossible to manage in a tethered relationship.

Successfully aerotowing a paraglider with this method requires a change to the traditional paradigm of towed flight in which the glider must dutifully follow the tug. Both the paraglider pilot and the tug pilot will have to abide by a pre-coordinated plan for dealing with the continuous corrections that will be required. In the absence of such an advanced plan, the aerotow will be short-lived.

If our 45fps tug flew at 13° bank then his radius of turn would be 275ft at a leisurely turn rate of 10° per second. To achieve the same turn rate with the 30 fps paraglider, it would use 9° of bank for a radius of turn of 178ft. At these conditions I computed a 160 ft towrope as optimal. Under these conditions the paraglider is approximately 45° off axis from the tug (i.e. with both aircraft in a left handed turn, if the paraglider is pointed north, the tug would be pointed northwest).

While this would normally be disconcerting to a tug pilot used to conventional aerotows, it is possible to tow with the line leaving the tug at a 45 degee angle (and only 70% of the tow tension providing thrust to the paraglider). As always, though, the paraglider pilot should strive to keep the towline square to the harness and canopy. Note that if the towrope was routed to the tug's tail then the drag of the paraglider would always be trying to pull the tail inline with the glider and the tug would have to have sufficient rudder power to counter the torque of the off-axis tow or else have some sort of CG/bridle hook up.

If both aircraft are climbing out at the same rate then everything is perfect but chances are there will be some errors. Here is where the pre-planning is required. If the tug is climbing faster than the paraglider, then the paraglider should decrease its bank slightly to increase its speed and climb rate. If the paraglider is climbing above the tug (more likely) he should increase his angle of bank to cut to the inside. Here is where a smart tug pilot will make or break the tow.

He needs to evaluate if the paraglider pilot has been doing a good job and if it has room to make the required correction. If the paraglider is slightly out of position but correcting back then the tug may just observe. If the paraglider pilot is already in the planned position (about 45° inside the turn) then there isn't much more he can do and the tug pilot should either throttle back or increase his bank angle to decrease the climb rate. His course of action should be based upon his interpretation of the paraglider's 3-D position and heading (if the paraglider has dug far inside the turn and the tug turns harder then the paraglider will have to deal with a huge change in heading and possibly even slack line).

If the plan is properly coordinated and well flown by both pilots then a small payout winch could be mounted on the tug. The purpose of the winch would be to handle short periods of excess tow pressure. The winch could simply be a large fishing reel with some pretty small towline (or large fishing line - depending upon your point of view). I'm not a fisherman but I think you could get a commercial product with 500 feet of line that only weighs a few pounds.

You would set the drag for say 20% more than the planned tow force and it could handle short periods of time while the aircraft are transitioning back to the proper positions to reset the planned steady-state conditions. A small electric motor could wind the line back in at the completion of the tow. The reel should be mounted in the field of view of the tug pilot and the line could be routed through guides or pulleys to route it clear of the propeller.

(editor’s note: I believe that all of these methods are being looked at and attempted in some cases at Quest Air.)

Discuss aerotow paragliders at OzReport.com/forum/phpBB2

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Flying the flag for foot launched flight

Thu, Apr 24 2003, 5:00:06 pm EDT

advertising|bungee jumping|communication|cost|electric|equipment|FAA|FAQ|fatality|Florida|game|job|landing|magazine|news|Oz Report|PG|picture|radio|Rod Clark|safety|sailplane|site|space|speed gliding|sport|students|USHGA

Rod Clark <Rod.Clark@ge.com> writes:

Since beginning to hang glide I’ve become acutely aware of the need to bolster participation in the sport. It’s clear by reading The Oz Report, and Hang Gliding and Paragliding Magazine that our sport needs new pilots. I’ve seen discussions on marketing in The Oz Report, and as a marketing person myself (for General Electric. Yes… I bring good things to life) I began thinking about how we can grow our sport.

I had a chuckle when I saw the “We need your friends” ad in the HG and PG magazine. I’ve been trying to drag friends into the sport since I began, and haven’t been successful once. As a marketing campaign goes, it’s a bit silly. USHGA’s target market isn’t people interested in me (my friends). USHGA’s target market is the people who’ve always dreamed of flying, but weren’t exposed to our sport. Thus, I’ve put together a few ideas about how we can capture the hearts and minds of those individuals and really communicate a message to them. Soaring is a reality, and it’s available to you.

My plan boils down to two basic premises in marketing; Identifying a target market, and providing for them an awareness of our sport. Let’s look first at the target market.

Paraglider pilots are the first and most obvious choice. First, paraglider pilots are already interested in soaring and have already taken the first steps to make their dream come true. However, because of the overlap in flying conditions, Hang Gliding offers Paraglider pilots an opportunity to fly when they might otherwise be to strong. Every USHGA instructor should encourage all of their students to become biwingual at some point in their flying career. It’s good for the sport and the pilots.

Although sailplanes are in the same dire membership situation we are in, it is a source of potential hang gliding and paragliding pilots. Although much of the sailplane community is older, there is a core group of young people that hang gliding may appeal to. I personally was never interested in hang gliding per say. I wanted to soar and I wanted to fly sailplanes. What I really wanted to do was fly, and when I realized the drawbacks for sailplanes (they are expensive, easily breakable, must always be flown within distance of a landing strip, much more work in the air, and the tiny excuse for a cockpit that you are claustrophobically stuck in) I began looking elsewhere.

A low cost marketing campaign would be to make an alliance with the SSA and “swap” (by swap I mean run ads without charging each other) advertising space in our respective member magazines. We could run ads saying “think outside the bubble”, “think smaller”, or something silly like that. Push the idea that flying with the wind in your face is the dreamy alternative, that high-performance hang gliders are almost reaching 20:1, and you don’t have to pay for tows.

One of our best sources is the FAA/AOPA private pilot community. How many times have you heard this story. We all have friends who are licensed private pilots who are not flying, or are not even current on their rating. Why? There are several reasons. First, renting Cessnas is terribly cost prohibitive. Who can afford to go flying at $70 per hour? Not me, and truth be told, not many people. My best friend has had his private license since he was sixteen. He’s thirty now with one kid and probably hasn’t flown in a year (not because he doesn’t want to).

Second (and most importantly), most private pilots are disillusioned by the idea of flying. People are drawn to flying from a young age. Every kid runs down the sidewalk with their arms out like a bird trying to lift off the ground. They imagine the wind in their face, swishing and swooping with the birds. Then, when we become “grown-ups” we seek the most obvious choice, a private pilot license. After getting licensed most pilots come to the same conclusion, “This isn’t like my dreams of flying”.

Frankly, flying a Cessna sucks. It’s noisy (really noisy). The cockpits are awful (like flying a Yugo). The windshield is usually scratched up to the point you can barely see out of it. You are severely restricted in where you can fly, and what you can do when you fly there. Headphones and an almost constant communication with an air traffic control tower make the dream of “running down the sidewalk with your arms out” seem more like mechanized warfare.

Before those perspective pilots become to disinterested (or go broke renting planes) let’s capture them and bring them into our sport. Again, our two governing organizations can “swap” advertising space in our member magazines. FAA/AOPA can run ads saying “Go further” or “Have the batteries in your lift died”. USHGA can run ads saying “What’s the buzz all about” eluding to the noise of the cockpit. We need to exploit our strengths (like cost, noise, fun) and share with them “this is closer to your original dream”. Also, break the common reply “I need a motor to feel safe” by describing how you can always fly within gliding distance of a safe landing spot.

Let’s also cater to the idea of owning something high-tech. Show them high performance wings like the ATOS or the Talon and give them something to get their mouth watering. Most people like the idea of owning something. Since hang gliders no longer look like “the bamboo butterfly”, we can advertise “You can’t afford that Cessna, but you can own this super-high-performance-flying machine for less than ten grand” (well, sort of). I read in a recent article of Flying Magazine how cost prohibitive it is to own a twenty year old Cessna 182. They estimated total cost of ownership at over $22,000 per year, or $179.00 per hour to operate. Let’s sell them our toys for much much less!

Heck, I could lay out the ads if you can negotiate the free advertising space. Additionally, my swapping idea is really effective if we get placement on their web sites (and this goes for all of my markets).

RC pilots also make a great audience. First, the hobby is thriving, especially in the electric and sailplane/electric markets. Second, the audience spans all generations. RC pilots start as bright teens and carry on well into their twilight years. Many of the “twenty’s and thirty’s” pilots probably do not realize that our sport would allow them to “actually fly” and in many cases be comparable in cost (have you priced a comp RC sailplane and 8-channel computer radio these days?). For about the same cost as a nice RC sailplane you can own a Falcon. Again, swap space in AMA’s magazine and on their web site.

I struggle with some of the following suggestions, because it may sound as though I’m contradicting myself. We need to grow our pilot base by appearing as an intellectual sport, and Zen sport, but a large audience is the X-Games generation. Allow me to address these individually.

First, the perception in the mind of the general public is that hang gliding is for the lunatic fringe and the thrill seeker. A common response when somebody hears that you are a hang gliding pilot is “Oh, do you also skydive and bungee jump”. Bungee jumping is a game of crapping your pants for eleven-point-five seconds. Hang gliding is a sport of Zen like concentration. Those who endeavor (and survive) are typically intelligent, conservative people who thrive on the extreme concentration, strategy, and constant decision making.

In a way, Rock Climbers are an excellent target market for hang gliding. Have been a former big wall climber myself, I can tell you this first hand. In rock climbing (as in flying) you really hope that nothing “exciting” will happen. A climber may work diligently and focus intensely for hours on end trying to reach the summit. During that process, a Zen like clearing of the mind and all of its worries is achieved through a purging of any excess, allowing for a clear calming focus. Sound like a light lift day to you? We can appeal to this audience. Put an ad in Rock and Ice magazine saying “Seeking a higher Zen, try this”.

The part that I struggle with is this.

We need to appeal to the X-games generation. Rock climbing, hiking, mountaineers, pilots are all a similar breed of conservative individual. These people are the same age as the X-gamers, have common interests with X-gamers, and are in the same overall demographic, but are fundamentally different in their willingness to put their life on the line. I fly because I feel it is safe. I am a pilot, not a lunatic. I’m also from the X-game generation.

The tough part is, we need the exposure of something like the X-games to bring people awareness of our sport. The down side is that we may not want some of the people it may bring (freestyle motocrossers come to mind). The last thing hang gliding needs is a surge in popularity by reckless thrill seekers and have our annual fatality rate skyrocket. We must choose carefully which genera we appeal to. X-gamers will likely be enthused about speed gliding. But that enthusiasm could in the long run kill our sport. Can the WRE make it as an X-game or Olympic test sport? We should ask.

The second part of my marketing plan (the first being target marketing, which we just covered) is about awareness and perception of the general public, and making hang gliding desirable and accessible.

The first issue to tackle is the one of safety. The perception in the mind of Joe Public is that hang gliding is a dangerous sport. Because of the steep learning curve just thirty years ago, this worry is not without merit. However, whenever hang gliding appears in the press outside of our circles, it is important that we stress that the sport has evolved into a safe, fun activity with high-tech equipment and structured teaching. Instructors and pilots must preach this to prospective pilots.

Having said that, USHGA should have a public relations person (even a member volunteering their services) to actively communicate with local news papers whenever an event is taking place in that area. Beyond that, we can even push for story placement in lifestyle sections of the Sunday paper. This is especially important in markets with such huge potential (such as those in California or Florida). Articles should stress safety, soaring as a sport in general, and the opportunity for every man and woman to become a pilot. And emphasize, “We are not the lunatic fringe!”

Once these open minds have been captured an exciting web portal must be available for the prospective pilots to explore. I believe that an exciting and graphic FAQ section on the USHGA web site is highly desirable. Current visitors to the USHGA are greeted with a very business like web site, designed to suit active pilots and instructors. For that purpose, I believe that USHGA has done a very good job. However, a picture section, with descriptions of different facets of our sport would be highly beneficial in capturing the imagination of prospective pilots, and furthering their dreams of soaring.

Since the low cost, compared to any other type of flight, is a highly desirable trait, we really must emphasize it. You’ve all had a look at your fellow pilots. You know that most of us are of modest means. When I initially became interested in Hang Gliding, the first instructor I contacted only offered package deals for lessons. I thought, jeez I can’t plunk down $1400 up front! I ultimately chose an instructor that allowed me to pay per lesson. In my opinion, all USHGA instructors should offer per-lesson plans. We have to make it as easy as possible for anyone to become a pilot, and not give any reason to turn them away.

We’ve developed a bunch of great single surface gliders. Now let’s get some new people excited about using them!

Discuss “marketing” hang gliding at OzReport.com/forum/phpBB2

Discuss "Flying the flag for foot launched flight" at the Oz Report forum   link»

Zwecki

Wed, Apr 23 2003, 4:00:04 pm EDT

electric|Josef "Zwecki" Zweckmayr|Oz Report|Thomas "Tom/Tomas" Weissenberger

Thomas Weissenberger <tomtom@direkt.at> writes:

Two weeks ago I and the other Austrian pilots celebrated Zwecki´s birthday. We all met at his home which is in a small village in a little valley in the middle of nowhere. I would call it the Austrian Tigerland.

Zwecki is now back home from the rehabilitation center in the lavish care of his parents and his girl friend. They renovated his house to make it suitable for him to move in his electric wheel-chair. He is still sitting in the chair, but his mind is totally clear and full of optimism! The most significant thing in my eyes is that he still thinks and talks with us about flying. He is listening curiously to hang gliding stories, he talks with us about flying and he takes part at some of the Austrian pilot meetings.

He might be away from the comp scene physically but he is watching it fully interested. Next week end we have a comp in Austria where he will be involved into the task setting and briefing. With his left hand he can use the computer and he is also reading the Oz Report!

I am writing this to let everybody know about Zwecki´s whereabouts and that he is happy about any support of all the pilots who know him!

Zwecki is now 34 years old. Birthday greetings to: <j.zwecki@aon.at>

His next goal is to fly sailplanes. See you in goal Zwecki!

Discuss "Zwecki" at the Oz Report forum   link»

Platz Glider

Sun, Mar 23 2003, 8:00:11 pm GMT

Bill Berle|Brett Snellgrove|Daniel "Dan" Gravage|electric|Platz|power|sailplane|tail|travel

Brett Snellgrove <Snelly14@cs.com> writes:

It was with total amazement that I saw Dan Gravange's posting regarding the Platz wing one issue before mine. Although it appeared otherwise, my posting was not in response to his and quite an amazing coincidence that shows the ongoing interest in this design.

Although I must bow to Bill Berle's experience with models (vastly superior to any hypothetical musing) my attachment to this design makes me reluctant to give up on it so easily.

Firstly, I see an inconsistency regarding Bill's comments on roll control. From the photos I sent you (not the ones posted thus far) it is quite clear Platz is freely and easily soaring a long dune ridge -- this would be difficult without adequate roll control and impossible with none at all as Bill noted. Secondly, Bart had found documentation describing excellent roll control up to and through stall in both models and the final design and clear documentation that the rudder Bill considers necessary was not needed. Something's amiss somewhere.

Bill surmised that the absence of roll control in his model was due to drag created in closing of the slot on the down going canard. In the photos it appears the canard was well forward and up of the main wing -- too far in my view to form an effective slot. If this was indeed the case I see 2 solutions.

One would simply to be to use upward motion only on one canard, no downward on the other. If indeed the down going canard did cause excessive drag then perhaps downgoing motion only, similar to a paraglider brake would be effective?

Bill also described difficulties with trimming the model. If as I, suspect he copied earlier designs shown in the photos, and the canards were hinged at the LE, this would be expected. Hinging at the ⅓ rd chordline as Platz later did might solve the problems Bill encountered. I suspect Bill rigged his model hinged from the canard LE and with equal action via RC servos. In reality the Platz glider was flown with the hands, hinged at the ⅓rd chord and a good degree of differential action allowed such that the pilot could manipulate the controls independently to effect roll.

Bart also notes sailplane clubs were considering usng Platz's wing as a trainer. I find it difficult to believe they would do this if the problems Bill notes in his models weren't somehow solved (without a rudder).

Bill Berle <auster5@earthlink.net> writes

I took a few photos of my Platz glider model.

The model was built of curved laminated balsa keel and mainspar, covered with Japanese tissue held to the frame by glue stick. Thread formed the trailing edges of main wing and canard/jib surfaces.

An electric motor platform was added at the front of the keel. I used a rubber block with the canard strut wires held in place by friction, so I could easily adjust the decalage and control inputs.

As I mentioned before, I could not get the model to turn in a reasonable circle with the canard jibs alone, either in a glide or under electric power. I added a vertical fin, and was all set to put on a rudder (which I was and am confident would have added proper control authority). But the model was not able to sustain level flight with the electric motor weight, and the repairs were already too numerous, and I simply retired the model.

I had gotten the information I needed, which was that some form of yaw control was needed. As an alternative to the fin and rudder, drag spoilers on the wingtips that "pulled" one wing back would more than likely provide plenty of yaw control without changing the basic shape of the Platz design. The moment from the CG to the rudder would have been even less than the moment arm from the CG to the tip drag spoiler, so yaw control would have been very effective.

Brett Snellgrove writes:

I built a model of the Platz glider today and believe I solved the riddle of how Platz achieved sufficient roll control to soar dunes. Firstly, the glider flies very nicely and is remarkably stable considering how close to the mainwing the canards are -- yet it seems to fly with the stability of a tailed design without a long tail lever. This alone makes it an attractive option.

The glider is quite responsive in pitch to uniform motion of the canards. I noted that same thing Bill did in that aileron type deflection produces little change in direction. I suspect the drag of the downgoing canard produces significant adverse yaw. I then tried unilateral canard deflections and as expected, one canard deflected downward produces a diving spiral to that side.

However a unilateral deflection upward produces a nice rapid flat turn to the same side!! This may be due to the closing of the slot as Bill notes but I think it is simply due to the extensive drag associated with a large upgoing surface deflection associated with mainwing dihedral. There appears to be no roll away from the upward deflection and significant, now proverse, yaw associated with the turn. I suspect the dihedral of the mainwing cancels what would now be adverse roll? There does not appear to be a significant pitch up associated with the turn. Possibly the loss of lift on one side compensates for any upward pitching motion.

Platz would have most certainly experimented with rolling the glider during the extensive tethering tests and not attempted free flight without effective roll control. Given Bill's and my experience with models this seems the most likely solution. So it conceivable Platz discovered paraglider type control years before MacCready did the same thing with the Gossamer Condor. In fact the wing would be flown exactly like a paraglider for pitch and turning and should make for a very simple transition.

Bill Berle writes:

Brett, I think either you or I have something backwards. When you describe a unilaterally upward or downward "aileron' deflection I think we have it opposite.

On the fixed wing aircraft designs that I am familiar with, an "upward" motion means that the trailing edge of the control surface moves up. In the case of the Platz, I would expect an "upward" motion to mean that the control handle at the rear of the canard boom was raised up above the pilot's head. In this case "upward" motion of the canards would be making the glider dive, the same way as upward movement on the canards of a Vari-Eze canard power plane makes it dive.

A downward motion would mean that the trailing edge of the canard moves down, making that canard produce more lift in theory.

What do you mean by a "unilateral" upward motion? Do you mean that the pilot would raise or lower the handle? Do you mean that he would move it all the way full travel up or down?

I think I understand your results after reading it a few times, but I still cannot get how using full "up-elevator" control on one side (to cause a drag-related turn) would not ALSO act like an elevator and raise the nose at the same time.

Although you may be able to trim the glider into a level flight turn using the method you discovered today, I still strongly suspect that using the canards as a drag device would have some negative effect on pitch control especially if you needed it at the same time.

Brett, please leave room in your model to try the tip spoilers I suggested. I think that little tip spoilers or drag plates would allow you instant, smooth turning control that more importantly did not interfere or affect the use of the canards together for pitch. I would bet that at the end of the day, this is the control setup that would allow a safe man-carrying version to be built.

When the time came for it to be flown in "big air" as the HG pilots say, I would bet what's left of my balls that a fixed or movable vertical fin would be the only thing that would make it safe to fly. Dihedral is not a substitute for yaw stability dihedral only rolls the airplane the right way for any given yaw. So when a gust blows you 45° off course into a hillside, at least your yaw string will be in the center on impact.

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