Experiments in Stabilization of R/C gliders - RC Groups
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Aug 17, 2017, 08:17 AM
Ben
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Experiments in Stabilization of R/C gliders


Now folks, this is written off the cuff, sort of meandering and sharing the thoughts of an ol Fart glider guider, so go easy on me. As time permits, I'm going to explore stabilization, in gliders. More specifically, the electric glider. You must realize that as the rules now stand, not much of what I will discuss below will be usable at contest, but remember I fly my gliders 95% of the time for fun, Contest, where the sky's are blue and the BS knee deep, are just gravy now. Having flown gliders since 1967, Varios for 40+ years, stabilization of some form for 30 years, I am a true glider fanatic.
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October 17, 2017
Whew, been busy lately. Testing, flying, working with my "Cyclops Storm" autopilot. Took me a day to get it working right. Rediscovered ground loops, fixed with a secondary isolated switching PS for the "Radio" side of the AP. and noise on signal, twitching servos from lack of shielding on all cables, it's amazing that it works at all but finally got the bugs worked out "I think". Yesterday, finally flew it in my trusty old Paragon, with stabilization on Rudder and Elevator! Whew. It works great on elevator. Rudder is another thing. Watching the recorded video from the plane, over 5 flights, it simply can't handle it right. Kept lowering the loop gain and it still was a drunken sailor! Arrrggggghhh. It sort of works but with the RTH (Return to home) function, it really wanders all over the place getting Home. Last night, modified my flaps and converted them to Ailerons being controlled by the Cyclops. While testing on the bench, the HSI simply disappeared! Have to check the menu, maybe I turned it off accidentally. (Yep, turned off in menu) back on. Being a "newby" with a full blown AP in a glider, is like pulling teath! Found out that the system defaults to FULL down when the battery dies! Noticed my voltage was low and was in automatic RTH function. It does that when battery low. Dove down from 5-600 feet, came around to land, about 10 feet off the deck, flaps down, it decided to die! FULL down, straight into field. Going to put my battery back up in the plane, ensure that it never happens again! Lots of parts but very little damage. Love the soft FL sand and grass in the ball field where I fly! Wing was NOT hurt at all, camera still attached to wing. but rubber bands did their job and it shed the wing. Canopy was trashed and one former in the nose was broken by battery. Battery was DEAD! All fixed. Discovered that there were two grounds on the camera and if you don't use both of them, RF kills the camera! I"m running 5.8 Ghz, 200 Mw for the video down-link. Can crank it up to 600 Mw but don't seem to need it. Seems to work anywhere around the field. Shessssshhh. Today, cold front coming through St. Pete so can't test it out new Aileron setup Too wet, too windy. Will miss the flaps and no spoilers but plane is rugged enough to dive down if I get to high and have to be careful with landings. Thursday and Friday I'll take a break from "Auto Pilot" fun, test Hyper Ava and Pulsar, have to charge all my battery's for the contest up in N end of FL at FSS#5, San Felasco St. Park. Life is good.

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October 4, 2017

Had a great little contest a couple weekends ago in St. Augustine, FL. Weather was a bit brisk, some rain, some wind, some "fire ants" but a great contest. https://www.rcgroups.com/forums/show...pt-23-24/page8
A great flying field, a good bunch of fliers, had a great time. Came in third in class on Saturday, 4th on Sunday. Life is good.
A few bites from "Fire Ants" when I stuck my Ava's nose in a nest! Instantly Ava was covered with hundreds of the little buggers. Not realizing what they were, picked it up, and was brushing them off when I realized them suckers were biting back! Lots of jumping around, slapping, etc. We had lots of new pilots which is a good thing. Missed using the AP's but heck, I was there for fun! I'm working on long distance FPV right now using my old gliders, want to get where I can fly start to finish on the goggles. Want to fly one flight at a contest from the cockpit just to do it. Anyway, windy here for next few days, grounded till it calms down. Have my Paragon set up with Stabilization on elevator and rudder to see if I can use rudder stabilization to simplify control system. Years ago when I tried it, I ended up with a lot of wing waggle back and forth, stable but not very pretty! So work, work, work!!!!!
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September 14, 2017. Well survived "Irma", everything is OK. Lost power here at the condo so spent a few days down in Bradenton with daughter till they got a handle on things here in St. Pete. Looking forward to the contest. Hope the weather calms down for the next few weeks!
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Sept. 7, 2017 clear and hot. Very light NE wind. Has been very calm for the last few days! Flew Hyper Ava for about 4 hours today, just relaxing and enjoying it before the storm here in FL. We all looking S to hurricane Irma making landfall Sunday. Last day of flying till after the blow is over. Ava loves to circle on a wing tip in lift! Had several 20 min flights just puttering around the sky climbing out, coming down, climbing out, played climbing/circling with and without AP. Each mode has advantages. Without AP, flying with the CG Aft, when I get real high and start to get squirlly (bad eyesight) flip on AP for 10 seconds and calm it down, then switch back off and tend to business of keeping the nose level and tracking around sky. .....Blue sky flying with a few puffies coming over later in the day. Flew from about 9 a.m. when lift and sink was crappy, then as day went by, got much better around noon. Flew till 1:30 p..m., then too hot, was 94 in the sun, felt much hotter! Life is good.
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Sept. 5 2017. Nice day flying. Partly cloudy, no wind. Today flew my 4 meter full house Pulsar. 5 flights, did not try to time them, just flew for fun, playing with trim, etc. I can honestly say that it is not as good pure glider as the Hyper AVA. I love the agility and precision the ailerons/rudder gives you but the sink rate just is higher! I also need to add a bit of nose weight to it as it is touchy as a cat on a hot roof! With AP, it flies great, really groves in pitch but without it, It is a handful. Probably because my CG is WAY AFT of recommended point. That's just the way I fly! Going flying again this morning, ( wife has hairdresser's a appointment) wind appears calm outside, partly cloudy. Looking South keeping an eye on Irma, I'll keep flying and practicing till it is just around the corner. I see where it is beating the heck out of the Islands. Everything is in place here on the West coast of FL, all we can do is wait! Raining all morning, staying home, field would be "squashy".........
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Sept. 3, 2017. 82 degrees, feels like 87, total overcast, humidity 75%. MUGGYYYYYY 9:30 a.m. Went out to flying field no one else there. Ground is soaked from rain last night! Flying the Hyper-Ava. It's a great flying RES airplane. 156", looks like a mosquito with it's long tail. Have Auto Pilot on board but not using, trimming and practicing for contest in 3 weeks. Flew 7 flights, 7 min, made all my times, moderately good landings. As not using AP, have to be especially sensitive to pitch and rate of climb info from the vario. Wind only 1-2 mph from the SW but rain and thunder in the area caused me to call it a day after those 7 flights. Flying in large circles, listening for any deviation of the tone in the vario or slight pitch up. A slight tap of down with pitch up converted very soft lift into a bit more speed and altitude plus would then tighten up circle. At the end of 6 min of the 7 min flights was still over 200 feet each time, love that plane. For the best sink rates, elevator is very sensitive to trim. Just a click or two can make big differences. Experimented on one flight with a much smaller lighter battery (normal battery is 1800 MAh for balance), moving the CG back to about 55%. Took 20 clicks of down to trim it out. Quiet twitchy but still flyable. Probably would have been a handful in turbulence. Sink rate seems about the same with that Aft CG maybe better. Will put a logger in it when I have time but can't do too much futzing around, have to keep mind on the contest. More experimenting with that. AP completely stabilized it in pitch,but again, can't use it in the contest. Arrrgggghhhh. Enough for one day!
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Why are glider pilots, especially the ones that come up with the rules afraid of an electronically augmented and stabilized air frame? We put dihedral in a wing to stabilize the model for RES/REF. We make the tail booms super long to stabilize in pitch, we keep the CG forward to also stabilize in pitch! So why not stabilize electronically to simply make a better flying model. Notice I said better flying model! It doesn't make the pilot better, just a better airplane overall. We all know the smoother you fly, the better the model flys and the better flight times you get. It can't be technology, we use laser part cutters, Carbon Fiber, Zap glue, etc. etc. So we embrace some forms of technology but damn that little stabilizer. All the excuses about cost, only beginners need it, etc. etc, just doesn't add up! So many areas of our hobby do use it, I just say why not! Just look at DRONES! Holy cow, the electronics in them just staggers the mind, and they are CHEEP!!!! Whats the ratio of drones/glider kits sold! See the problem?! Folks that make the Radian realize the value of stabilization, they take a well designed "foamy" and enhance it and that's OK. But from a home built Woodie on up, it's no stabilization! Why can a factory do it and a modeler not?????.....It just leaves me puzzled.:confused which I might say is easy at my age!

I, now at the age of 74 find that augmentation of stability, especially in the pitch and roll axis PLUS return to home when I get beyond my "old" eyesight is helpful to keeping me in the air. I realize this is not for the purest, fly by the seat of the pants glider fanatic, but it is a tool that does enhance many of the older gliders with shorter tail moments. (It also enhances ANY glider if the truth be known). I have flown with rate gyros in the early days, home made electronic pendulum stabilizers, pressure differential stabilizers, vane stabilizers and early rate gyros that I integrated into a working 2d type of device. All for fun (that's my other electronic evil side). Then the micro computers arrived and my world changed. Wow what you can do now!

Now, when flying for fun, what would we like a electric glider to do in the real world. Lets see:

1. Launch easy.
2. Fly well, have no bad habits.
3. Thermal Well.
4. Land well.

Now this is a simplification. Lets look at "Launch easy". What does this mean? I guess we would like it to climb at a nice rate of climb, steady, keep it's wings level, track over the top, and transition in to level flight with no messing around at the transition to level flight. Normally, we mix elevator and motor to achieve a stable climb attitude, but there is problems there and even with mixing, we end up flying the elevator all the way to our cut off altitude if a altitude limiter is used (for whatever reason).. Then we have to take care of the pitch over at the top to prevent a "zoomie" stall, etc. and get it flying smooth. A lot of variables a pilot has to overcome to do a nice smooth launch. I might note the better the model is set up, the better it flies, the better it works in the power portion of the flight and transition thereafter.

What does fly well mean? Ha...you could write a book on this subject but I will simplify. OK?you have it launched, its up 5-6 hundred feet. Now what. Does it fly level not turning left or right? Does it fly level, nose not oscillating around the horizon? Now when you turn it, does the nose drop? Do you have to compensate on elevator/rudder when turning? Does the nose bobble around when it hits a thermal? Does it groove around in thermal turns, normal turns? When you use spoilers or flaps,(speed, cruise, thermal modes?) does the nose diverge from straight and level, Do you have to add compensation for this in the elevator/spoiler/flap mix? Is this mix speed dependent? Does the mix work at all speeds? IF you lower the nose 45-50 degrees to dive out of "killer" thermal, does it stay stable at that pitch angle or do you have to constantly fly the elevator to keep the dive constant?

As you can see, the pilot work load gets pretty heavy just flying around, then we haven't discussed landing yet.

Landing... Ha, that's where the fun begins. You get more "Awwww #$#$%#%ts, in landings at contest than anywhere else or in any landing.
So you come around on final, headed towards the spot, your buddy, a chair, or a tree, speed a bit high, OK, time to put up the spoilers, whew, nose drops, OK, bring it back up, hum a bit low now, speed bleeding off, arrrrgggggg...wind gust slows it down some more and gust is off to the left. Now your low and slow, a compensating for drift, speed, distance. Yikes, it's work now but your still grinning but darn, your 10 feet outside the spot, Zero points for landing or walk of shame if buddies watching. But still a perfect landing, just not where you wanted to be. IF you were using flaps, same thing but nose pitches up if speed to high for compensation to correct, again, your making butter with the sticks, flying that sucker and grinning like heck and we are still having fun!

Now lets just skim the subject of stabilization here for a min. There are 2 basic types of stabilization, Rate and Absolute.
Short and sweet, 3D (RATE), the control surfaces respond to change in the airframe's attitude with an opposite short input temporarily and lets the airframe integrate it out, therefore it "smooth's" the flight pattern. Absolute, Proportional, 2D, whatever you call it, integrates the error referenced to its own set point and drives the airframe to that point in space. The best is a signal partially rate (3D) for quick recovery, and proportional for long term, absolute recovery. I can not overstate the absolute perfection in the software and micro hardware available to the hobbyist now. It just boggles my mind.

The hardware is shown in my "OL Yellar" beater Windrifter that I try all the crazy stuff I think up. Basic flight controls are Rudder, Elevator, Ailerons and Spoilers. In the picture at the bottom of this blog, the hardware is as follows from left to right. GPS receiver, Vario, Guardian 2D elevator stabilizer,
Guardian 2D/3D Inertial Stabilizer Demo (5 min 47 sec)
[url],


Aileron 2D stabilizer/RTH unit (Bigaole BGL-6G-AP)
BGL-6G-AP - Set up Testing (5 min 21 sec)
on Youtube. Beside it is a FrSky X8R receiver, then 2 servos, ESC with 5A BEC and good ol motor. Not shown is a 1800 mAh battery that goes on top of ESC. I converted my flaps to ailerons on the inboard sections of the wings (Old Drifter is highly modified) and kept the spoilers for lift control. Surprisingly, the inboard ailerons with normal differential work really well for stabilization in the roll axis. As you will see, I use a sort of specialized system of 2 very small inexpensive auto pilots to do what I want to do. Check out the Pixhawk system. https://pixhawk.org/modules/pixhawk Less that $100ready to go. http://www.ebay.com/itm/Pixhawk-PX4-...4AAOSwTZ1Xmvrk


That is our future! If anyone screams "Arrrrrrrrrrghhhh" too much money! First check out 95% of all models at our current contest, most are in the $2500 to $3000 range, flying and in the air!

Now lets talk about the Guardian set up for 2D on elevator. The "gain" is variable from 0 to 100%. via a simple knob on the transmitter. During launch, you set the gain for a nice climb out at what ever angle you want to fly and it holds it steady during that time. I start with the gain a bit higher than what I need. When launched, the glider goes pretty straight and level out away. I then gradually REDUCE the gain which allows the nose comes up until it is in equilibrium with the auto pilot at the angle I want to climb out. Too little gain and it will be going vertical, too much, it will flatten out. There is software in the Guardian that prevents using too much gain where it would oscillate, if you turn the gain up at the higher speeds encountered in climb out, it automatically reduces it to smooth and easy and then try's again to increase the gain. A loop going on all the time. It holds itself right on the edge gain wise of oscillating if a high gain setting is given. How this ties in with the Aileron auto pilot with a fixed gain we will discuss later. But for now, within a rather wide CG range, the autopilot will always keep the model at the "set point" that it calls level. REMBER that statement. This is set during the initial setup and never seems to need to be adjusted again. The Guardian is one amazing stable little device. I don't use the Aileron AP part of the Guardian as it does not have Return to home (RTH) Via. GPS built in so I use another AP for that. I can fly a large range of battery weights without changing any trim settings in the model or at most a click or two. As far as trim goes, a little autopilot goes a long way for maintaining nominal trim in real life conditions. With moderate gain settings, trim does NOT change with any degree of flaps or spoilers, all you see is the ship slow down with full flap extensions with the nose level! (Or tend to speed up a bit with spoiler extension) If you dive the model at say 60 degrees with full flaps and hold the stick at that point where that angle is obtained, it will continue to dive at the same angle, no mucking around, no tucking under, etc. Just a very controlled dive. Such a nice advantage for those situations.

Lets back up just a bit and state what happens when you move the stick left or right in a stabilized airplane. DEPENDING on gain set in Auto Pilot, throw sensitivity set in transmitter, mechanical throw sensitivity in the airplane, when you move your stick to the right 20%, the airplane will bank X number of degrees and hold that bank till the cows come home or you return the stick to neutral. The angle doesn't increase or decrease, it stays there! This is a fully stabilized airframe. While holding that bank, if it is buffeted by thermal, wind gust, hawk strike, etc. it will hold that bank angle indefinitely.

IF you are holding that X bank angle and your elevator is also stabilized, it will attempt to hold the nose of the airplane in a level attitude also till the cows come home. By doing this, it will add the necessary UP elevator to keep this attitude. Hence the perfect thermal turn. IF you have the gain TOO high, it will stall the airframe if you pull a 60-70 degree bank and it attempts to keep the nose level which it cant as airspeed drops too much, wing stalls and uppopsie daisy, ease off and get it back. IF you are circling in a thermal and decide it has drifted off to one side of the turn, simply open up the turn and "slide" over to where the better lift (Or buzzard) is.

IF you push the stick forward and hold at the dive angle you want, and hold the stick at that angle, it will dive smoothly till you decide to level out which you do my releasing the stick back to neutral, whereupon the glider will smoothly and quickly level out at high speed, bleed off the speed at that level attitude until everything is back to normal. Spoilers and Flaps will not effect the level attitude with a change if gain is set to a point above where it can overcome the forces/attitudes added to the airframe.

One more small thing that pitch stabilization helps with immensely is the phugoid (and pilot induced) oscillation of any stable airframe. This simply means that it is always oscillating around the horizon. Pitch stabilization simply takes almost all of this away and is VERY helpful from a efficiency standpoint. That's all I'll say on that subject.

IF you fly a glider with 2 axis stabilization for a few hours, going back to a non stabilized and very well trimmed airframe is like going back to stick shift, no power steering, hand brakes type of machine. It really is crappy. BUT.....

As the next contest I am going to does not allow stabilization per AMA rules, I'll just work on my mixing setup in my Hyper-AVA and practice, practice, practice....

Good Air
Ben
Last edited by k4zep; Oct 17, 2017 at 09:08 AM. Reason: Add Stuff!
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Aug 19, 2017, 01:52 PM
Registered User
Don Stackhouse's Avatar
The problem is that at least for thermal soaring, you need the visual feedback of the model's reactions to the air currents to tell you where the thermals are. An auto-stabilization system would mask that.
Aug 19, 2017, 04:31 PM
Ben
k4zep's Avatar
Quote:
Originally Posted by Don Stackhouse
The problem is that at least for thermal soaring, you need the visual feedback of the model's reactions to the air currents to tell you where the thermals are. An auto-stabilization system would mask that.
Hi Don,

Glad for your input. In the real world, the vario will tell you the vertical information
and there will be a slight increase in speed based on the strength of the thermal.
With the FrSky vario, the transmitter can tell you your rate of climb and your current
altitude. I have mine set to blabber the info every 4 seconds with the Vario tone in the background.
That way, I'm blasted with 3 pieces of information all the time as to what the model is doing.

When you fly a fully stabilized airframe, and once you get used to it, I can't emphasize how
much you get tied into it. Then again some of our master fliers fly so darn smooth and have
such good eyesight, I don't know if it would help them or not!!!!

I fly elevator stabilization on all of my gliders. I have to turn it off when at contest but in a well trimmed
out plane, it is much less noticeable flying around the patch. Same for the Vario's . Certain contest do not allow
Varios and I will be the first to say, I feel NAKED without them. I can fly just fine without it, but I can fly better with it.
Varios are most helpful in the super light air when for all except for the Master pilots, you don't realize you are holding
your own or going up 5-10 fpm./circle.
Aug 19, 2017, 06:53 PM
Registered User
Don Stackhouse's Avatar
But that's exactly my point. The visual cues are often the most valuable in figuring out where the thermal is. Visual cues, such as un-commanded changes in pitch, or especially in roll, can tell you where the thermal is even before you are in it, and long before the vario will have anything useful to say on the subject. And auto-stabilization will suppress those visual cues. We want, and we need to see the disturbances in the plane's attitude.
Aug 19, 2017, 08:45 PM
Ben
k4zep's Avatar
Quote:
Originally Posted by Don Stackhouse
But that's exactly my point. The visual cues are often the most valuable in figuring out where the thermal is. Visual cues, such as un-commanded changes in pitch, or especially in roll, can tell you where the thermal is even before you are in it, and long before the vario will have anything useful to say on the subject. And auto-stabilization will suppress those visual cues. We want, and we need to see the disturbances in the plane's attitude.

Point well taken. IF you are flying normal Glider setup, cues are most important. A real hard stabilization loop will suppress almost any deviation
caused by a thermal/gust, etc. A loop with less gain, but still adequate stabilization will show bumps, wing pushes, up or down depending on the position of the airframe. When you fly your glider and get tuned into it, a good pilot is tuned to every twitch, bump, wiggle in his quest for excellence I agree. Normally flying around just playing buzzard, I have my stabilization set pretty low, just enough to keep it smooth. Bump, vario sings, etc, start the turn, tighten up the loop and it just works. It's just a different feeling is all I can say. I guess it's just "try it" you might like it, maybe not. Every pilot has his favorite setups, favorite mixes, etc. Everyone's eyes, reflexes are different. One man's hammer is another mans Ax. I find it very useful, but again, its blonds and brunettes,
to each his own.
Last edited by k4zep; Aug 20, 2017 at 08:00 AM.
Aug 20, 2017, 07:35 AM
Ben
k4zep's Avatar
A avid glider pilot loves to fly, some may even say lives to fly. A bird FLIES TO LIVE, see the difference. That is part of the explanation why a 6' hawk can blow by a 12' glider in a thermal almost every time, he simply is better at flying and more efficient in extracting every bit of energy out of the environment he lives in. I get great satisfaction when a hawk, pelican!, or any bird will come join me in a thermal! That is group flying in it's purest form and tells me I'm doing something right.

You might get some enjoyment out of watching "Condor flight school"...Watch the feathers, the head, the turbulence in the feathers and the end, the flight path. Beauty in motion. Notice how "Mom" kicks her off the ledge for first flight!!! Talk about tough love!!!!!
Earthflight (Winged Planet) - Condor Flight School (Narrated by David Tennant) (2 min 33 sec)


Further flying enjoyment:
Dubai World Record Eagle Flight (uncut version, the full 5 minutes flight) (5 min 49 sec)


Even better MY FAVORITE one:
Camera was a bit loose, bird flew great! Having flown Paragliders in mountains, this one is just awesome!
Flying eagle point of view #3 (1 min 56 sec)



Bald Eagle POV flight - Chamonix, Mont Blanc (4 min 5 sec)




In our gliders, we have all sorts of hardware in our receivers, servos, variometer, battery sensors, etc. etc. Then we have software, it's in our receivers, battery monitoring circuits, vario circuit, servos, again etc. etc. Our transmitters are marvels of computerized technology. Never forget we started with big black ground based boxes with a button for control!

A bird has all the same "hardware" and software built in a self-contained regenerating body and all tuned to perfection.

I recently saw a lengthy video of a eagle flying in the mountains (see above) that amazed me. The camera was mounted somehow to his right wing, pretty close in. you could see his head and his left wing all the way to the tip. What amazed me the most was the smoothness of his flying. He was absolutely glued to the horizon pitch wise. You could see his wing tip feathers twitching around and buffeting around but overall, dead steady on that axis. Then he simply went where he looked! He looked left, the smoothest turn to the left, some very slowly, some like a fighter but the head/horizon always stayed glued to the perfect position! It gave me "goosies" just watching that perfection of flight. His wing tips curve forward and down as if he is caressing the air, then the feathers flair up! Love those vortex's!

Lets get back to PITCH stabilization. I'll try to define what I'm talking about. There is RATE pitch stabilization used in a lot of inexpensive, powered electric planes. It is the simplest. It just opposes any change in pitch RATE of change by an opposite control deflection. The elevator pulses/moves to correct or stop the rate change and then immediately moves back to neutral. The airplane integrates it out and appears to fly smoother. It has nothing to do with "2D or Attitude hold or wing leveling. A few trainers have a 2D "save your plane" switch that you flip on when you get out of wack, plane recovers to straight and level, then you turn it back to 3D and fly fly fly.

IN 2D pitch control, IF the nose deviates from LEVEL, it will immediately{based on loop gain] (2-400 ms) fly the nose back to the ATTITUDE it was flying before. Actually, its a continual proportional constant happening. You will see bumps in pitch mode very easily. IF a thermal bumps your nose up, the AP will level/push it back to the best angle of attack most likely almost before you even realize it. Its as if someone else is there working with you helping you fly better. Watching a "Master" pilot fly a glider smoothly, I realize that they are so tuned into the ship, all this is done by their eye/hand coordination and a hell of a lot software training inside their head without thinking. Remember also that every second a glider's angle of attack is wrong translates into a higher sink rate and less efficiency. The phugoid oscillation that all stabilized platforms we fly have and I mentioned earlier a day or so ago, is normally not seen but the AP sees it and dampens, eliminates most of it, again more efficiency.

Any energy picked up by that bump, will be translated into more speed. IF you are in a thermal all the way around a turn, you will see an increase in speed, just like you do in a properly trimmed ship. It took me years to understand the speed thing in a thermal. I used to slow it down when thermaling and wondered why I didn't climb as fast as others. I finally realized that you actually fly FASTER in a thermal at the same trim settings. BUT, its all about flying the wing at it's most efficient angle not just hanging out there. The speed you fly in calm air at best sink rate from an "ideal" point of view is what you would want to fly all the time. The problem develops in turbulence when the nose bounces around, the AOA is jumping up and down and the efficiency of the wing deteriorates! In a thermal when your speed picks up, a couple clicks of up trim (as the loop isn't absolute) are in order to do best climb rate and also the bring speed back to ideal. In reality this is what happens in a stabilized ship. You hit turbulence indicating possible lift, your vario starts to beep just a tiny bit faster, you can feel the ship speed up (I know your not in the bird but it feels like you are), you noticed the left wing push up a bit (it's a feeling actually you get), you turn to the left in a constant angle turn, it starts to speed up, a couple clicks of trim up to return speed back to ideal, and around you go and up you go.

I have a bad case of "NONFLYITUS" this morning. Wife and I have helping our daughter move into a new house about an hour away from here since last Monday. I have been writing this blog between hanging pictures, kick plates, door sweeps, setting up computer network for kids, fixing balky toilet the "home inspector" missed and a million other small things. Today (Sunday) is the last day.....I jump in here if there are comments, or I have another idea or thought on the subject, when on "breaks" catching my breath. I'm getting too old for this moving stuff but you gotta do what you gotta do! Here in FL, the average temp during the day is in the mid 90's and high humidity, it's just one big sauna.

This is the first time I have tried to put into words what I have been doing for years. I'm definitely not very good at the "words" thing! I have a lot of words, but....... I guess it's like asking a condor "How do you fly a thermal" and he would say "Very well".......You just do it after years of screwing it up!
Last edited by k4zep; Aug 20, 2017 at 09:23 AM.
Aug 20, 2017, 11:30 AM
Ben
k4zep's Avatar

MADres with 2D Stabilization


Elevator stabilization in a MADres glider. Totally not legal in competition but great for flying.
Been flying it when I'm feeling like having fun and sweating my ass off!
Clay is to balance. Electronic switch to turn on radio. Spring loaded switch to disable AP during
launch, turn on at top of launch.
Last edited by k4zep; Aug 23, 2017 at 10:49 AM.
Aug 21, 2017, 11:07 AM
Ben
k4zep's Avatar
Interesting flight this morning. Ironed a slight warp out of "OL Yellar's" wing, changed the master gain on the elevator loop a bit, wanted to test it all out. Wind from the East was about 12 on the ground, found out 15-18 above trees at field. Launched good flight, trims all OK, but wind was really strong @ 600 feet. Tested RTH, worked great. Decided to climb on up to 1000+ feet and play around. Boy was it strong up there. The city mows the field on Monday and right after I got up high, here came the mower. Big ol air conditioned John Deer, 3 bay mower. Friendly guy, stopped in front of me and said good morning and could I move back for the next pass. Said sure, looked up, no glider......arrrrgggghhhh. Well no BS, I said to my self, that RTH better work now or it is gone! This was not planned, not pulling anyone's leg, what happened. Hit RTH, a little throttle and waited. Kept scanning sky over head and downwind (Oh BTW, flying by myself), plane kept telling me it was at 1000'+ so I knew it was up there somewhere , Love my FrSky radio.....About 30 seconds later spotted the flash from tape on wing tips way down wind, still up high, but coming back! Damn was I lucky. Anyway, came on in, landed, thanked my lucky stars, packed it up and did some honey dooooos on the way home. Life is good.
Last edited by k4zep; Aug 21, 2017 at 11:13 AM. Reason: RTH is GOOD!
Aug 22, 2017, 12:37 PM
Ben
k4zep's Avatar
Another day at the flying field. A bit windy but not as bad as yesterday. Flying my Electrified Paragon with autopilot on elevator, sensitive Vario. Installed a new FrSky R9-900 Mhz radio it it. It is a direct drop in for the X8R receiver BUT watch the pin outs, they are reversed. With the matching R9M 900 Mhz module in the new inexpensive X7 transmitter, I just transferred the model from my Horus to it, changed a couple inputs and it was ready to go. I also immediately dropped a set of Hall Effect sticks in the X7 so I guess it is a "X75".... Range on the 900 MHz radio is exceptional! Last two flights, flew it at 10 mW output, fail-safe=Hold. At 1000' altitude slant out about 45 degrees, RSSI was still 48-55! Solid as a rock. It works just like a Taranis Plus except it doesn't have the side pots. I just moved the motor pot over to the LH switch on top of the transmitter. Mixing, etc all remains the same. Just wish it had a charge jack on it, will modify it soon for that. Although, the 2000mAh battery will last a long time at the low power setting of the output R9M module.

The reason for switch to 900Mhz is I plan to add OSD to glider. The E-Paragon is not for competition, just for the pure pleasure of flying. As a no longer flying Private Pilot, I still dream of being in the cockpit, looking around while I fly, etc. Will add a servo driven camera possibly with head tracking to give me the feel of looking right and left! The possibilities are endless. All this takes time. Life is good!

Good air to all.
Last edited by k4zep; Aug 23, 2017 at 10:55 AM.
Aug 24, 2017, 10:31 PM
Ben
k4zep's Avatar

Bad day in Carbon Fiber City~


Blew up my modified Xplorer 2.5 today during practice for upcoming contest.

It was just flying and climbing at normal climb speed getting ready to push it over at the top of 150 meters at motor cutoff. The wings are super strong, standard Xplorer 2.5 with the full flying stab. Stab was some sort of pink foam covered with a super light layup of fiberglass, CF rod and pin. About 1 ounce of led was in tail to balance at 135. Nothing it does or did would come near the stresses of a mono-Filament launch and I had it on some super winch launches before converting it to F5J. Prop is perfect, here on bench, was on tight, just a puzzle. No warning, no wobble, no gyrations, no 'Buzz" indication of flutter, nothing. One second everything was normal, next second, complete tail assembly pitching up and away as model tucked under. I believe it failed just forward of the Vertical Stabilizer on the top. There appears to be some funky glue on the center-line joint from a repair before I bought it second hand. I still had flaps and ailerons and with full down flaps I could keep wings level till it disappeared behind trees about 1000 feet away and ended up in fresh water lake (Aligators!) with NO damage except what had happened in the air and of course water damage to ESC/Battery, don't know about Neu moter yet till I let it dry out. I had a lot of good flights with it, can't complain. (but I sure can moan and groan a bit!) I guess it falls under (@#@$@%$%t happens). Would sure like to get a 4.0 Super lite but selling that 2K price to the wife is a hard sell!
Aug 28, 2017, 11:33 AM
Ben
k4zep's Avatar

F5JD (Drone)


While out flying this morning I came up with a great idea! Why not have a F3JD, F5JD ( D for Drone) division of sailplane flying. This would enable gliders to be brought up to date electronically and give a whole new meaning to "Fly by the seat of your pants!" The whole flight would be flown using Goggles with a camera in the glider. As real as you could get. Same rules except electronically, anything would go. Timer would be your spotter. For all of us retired pilots, this would make it REAL! Let me think this out a bit more, but watching the "Drone" fliers and the video from them, made me get an itch and wonder how to scratch it. Yes, I want to rock the boat! Or at least cause discussion about our hobby! I have a camera on "Ol Yellar" and got to get my wife out to act as a spotter and see If I can do it!
Aug 30, 2017, 03:26 PM
Ben
k4zep's Avatar
Quote:
Originally Posted by k4zep
Blew up my modified Xplorer 2.5 today during practice for upcoming contest.

It was just flying and climbing at normal climb speed getting ready to push it over at the top of 150 meters at motor cutoff. The wings are super strong, standard Xplorer 2.5 with the full flying stab. Stab was some sort of pink foam covered with a super light layup of fiberglass, CF rod and pin. About 1 ounce of lead was in tail to balance at 135. Nothing it does or did would come near the stresses of a mono-Filament launch and I had it on some super winch launches before converting it to F5J. Prop is perfect, here on bench, was on tight, just a puzzle. No warning, no wobble, no gyrations, no 'Buzz" indication of flutter, nothing. One second everything was normal, next second, complete tail assembly pitching up and away as model tucked under. I believe it failed just forward of the Vertical Stabilizer on the top. There appears to be some funky glue on the center-line joint from a repair before I bought it second hand. I still had flaps and ailerons and with full down flaps I could keep wings level till it disappeared behind trees about 1000 feet away and ended up in fresh water lake (Aligators!) with NO damage except what had happened in the air and of course water damage to ESC/Battery, don't know about Neu moter yet till I let it dry out. I had a lot of good flights with it, can't complain. (but I sure can moan and groan a bit!) I guess it falls under (@#@$@%$%t happens). Would sure like to get a 4.0 Super lite but selling that 2K price to the wife is a hard sell!
Well, Good News! Talked to Alex @ Soaring USA and they have a FUSE and Tail set at a reasonable price that I hope will be on the way in a day or two. It is the new two piece F5J Fuse and am excited. They answer Emails promptly and work with you. Excellent, I look forward to receiving it. Will show what I get and the process of putting it together. Had a great day flying today in the BLUE SKYS and heat over here! Thank goodness the rain is past!

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