This is an original for the San Diego Silent Electric Fliers year 2012 article.
Now a friend who is infatuated with RC flying, found us a decent (checked the Internet, what else?), if a little far away, hill in Rheinland-Pfalz (Germany) to slope fly RC on (far away here is thirty five miles and most of an hour each way, I scouted the area from bicycle for years, but what a pleasant drive on these, it stays light until after ten summer evenings), endured (and passed) the personality check of the club that flies there (almost anything worth doing in public in Germany is organized and regulated, but then, we are always flying on private property), bought the Simply balsa kit with an additional thermal wing. Me, being the former handworker (who, at the annoyance of the Harbor Soaring Society in Costa Mesa California was decreed a lifetime limit of twenty five flying wings), I the first SEFSD member with an EPP/Styrofoam flying wing at the field (a Zagi Razor), who already assembled and flew over fifty flying wings, agreed to build it. The extra wing, turned out to be an (appearently) entire kit for another different airplane.
I built my first EPP airplane back in 1995, and haven’t touched a balsa airframe (except for bought already built used) since. Not that I didn’t build some, but it was with Depron/fiberglass/carbon fiber. I haven’t built a wood fuselage since my last Ninja slope soarer, which had a six foot wingspan balsa over foam wing you could hit an oak tree at Point Fermin (Los Angles, California) with, and repair. Included building a Depron/fiberglass fuselage for some EPP flying wings so the motor and prop were in front to get away from that irritating prop noise of a pusher. Other then the associated wing joiners, wing hold down screws and so and so forth, this is a balsa kit. At least I have a flat surface to build on. And the experience from building a hundred balsa airplanes, including half a dozen Jedelsky wings, to draw on.
On opening the box, it includes materials for the slope wings and a fuselage. Where needed, the parts are milled out, or already profiled, everything looks good, really good. You get what you pay for, the kit(s) weren’t cheap (Euro112/$140-), the balsa is first rate. But if I were going to make the wing in two pieces, that hunk of steel rod for a wing joiner would have a carbon fiber piece paired with it for days when we want the least possible weight. Weird, the bigger wing uses two square pieces of fiberglass tube, and balsa, that would snap on the first hard landing or in the air! Not on my shift, that wing joiner is getting made out of hard wood, aluminum or otherwise reinforced!
This manufacturer, IKAROS (www.wing-tips.at), in the Southern Alps (Austria’s Lech River Valley, not far from my wife’s favorite vacation place, Lake Constance (der Bodensee), four hundred miles away, what a burden, now we have to go there), was profiled in the biggest of the German RC Flying magazines (FMT) about three years ago. He has also written some small books about flying. The one we have, about thermaling (which, due to where he flies in a steep alpine valleys, automaticly includes slope soaring) is reference standard not only for flying, also for being observant. It is so elegantly written, including the philosophy of observation air currents and the “professionals” i.e. birds, that I cannot easily translate it. And since it belongs to a friend, I didn’t read it while taking a bath.
I’ve been in Alpine valleys, they are inspiring, yes, you can see air currents play out. Here where I live on the Middle Rhein River, plains surrounded by rolling hills, you find thermals by watching how your airplane flies, and the birds. It’s not like we have nearly vertical canyon walls for the thermals to push up against. Any steep hills are covered with vineyards, or trees, or so rocky… Yosemity is about the only place in California I know of that would provide the same flying conditions as the Lech Valley. Few mountain ranges on this planet are as steep as the Alps, or the next door version, the Dolomiten.
Schweissgut’s writing is all the more impressive when you consider that standard High German (based on the ruling class of Hanover, in the far northwest) is not the social language of Austria (in the Southeast, the Lech lies in the eastern part of the Tirol region). In addition to formal standard German, I spoke the Swabisch dialect, and can usually follow the Hessian and Palantein dielects (at least near where I live), but I often can’t understand a word of the locals in Austria, Switzerland, Lorrain, Bavaria or Tirol talking among themselves. I have a better chance of understanding standard Italian as if it were Mexican Spanish then the people in Karten. Austria bears a similarity to Germany in that Canada resembles the USA.
In contact with Herr (Mr.) Robert Schweissgut per E-mail, that oh so personal touch may have contributed to my friend buying the second wing (which as delivered was the entire kit for a second airplane) and the book. After reading the book, I understand. His tales of watching the local hawks for flying tips (easier when the near vertical walls of the valley bring you that close to them, and the currents are so extreme, temperature inversions bring currents through condensation into focus the way we Hill Land Tiroleans could never experience), bring back memories of finding a lost flying wing on Cowls Mountain (San Diego, California) by watching the crows, and having a motor sail airplane with the exact same wing outline as the local to Wiesbaden falcons being shadowed by the “professionals”. Always the smaller of a pair of birds of prey, the male.
But with the US Army flying King Airs out of Erbenheim just a few miles from Under Igstadt bei Wiesbaden am Rhein, I just can’t go flying all that high near home. You can hear them coming, I pull down to under a hundred feet when they are active. So much for using the motor to get way up there with the hawks.
And, something about a little contact with the designer is satisfying, just like I always enjoy flying with our Steve Neu(motors)’s equipment.
Initial use of a sharp knife to separate the tabs and clean up with sandpaper took ten minutes, trivial also. It was the best balsa I have ever found in a kit. The white glue we can get in Germany is better then what we get in the USA, it will be used instead of CA. Where reasonable, I always stick with the manufacturer’s directions for the first of a series. That being really good balsa is important enough to repeat it, it makes a huge difference in building a balsa airframe.
The wing(s) are a radically modified (as described by the constructor himself) Jedelsky profile. If you can remember free flight, that is a seemingly complete wing profile milled out of solid balsa, to which a follow on flat plate (until this wing, always angled down) is attached. It looks hooky and heavy, but they fly well. Time to construct was, compared with ribs and spars, way less (a fifth, once you got the hang of it), they withstood damage well and were easy to repair. To date, my aversion to balsa (Never again I cried!) and finances held me back from trying IKAROS kits. That and they never came up used or partly built at the local twice a year big RC swap meet.
I used to be an structural design engineer, even before building aircraft hydraulics with CNC machines I irritated employers and coworkers by reading the directions first. Instead of the emotionless, or more often friendly writing in instructions, is the admonishment that Jedelsky profiles are found in nature, the beloved Stone Hawks he studied, and describes in his book. Yep, it’s a weird airfoil, instead of splicing the flat plate onto the trailing edge of the milled Clark Y profile (so it angles down), it’s but jointed (Stoss am Stoss) flat to it. This guy has a whole range of kits, and books, he must know something.
I’m proud to be an American, despite the many years in Northern Europe (and some time in Mexico), but if somebody is doing something completely different from our way, pay attention, they might have something. And the observation that (usually), no matter how dumb it seems at first, the locals know what they are doing. If the Simply wing works, it makes everything else like it wrong.
Two of us were thinking we could be jealous of where the constructor flies. I do balanced reporting. Ever wonder where he found the time to try so many different airplanes or write books? Winter in Wiesbaden closes me in, most of the time in the valley floor it’s above freezing, by the standards of Southern California there is almost no traffic, winter lasts about three months, nearly all of the year I’m out flying or cycling anyway. My real problem with winter this far north is darkness. Where the Simply originated, see the pictures of all that snow in the Alps from October through May. Lake Consance has, along with Wiesbaden, the best winter weather north of the Alps. At least if the weather gets to the constructor he can drive down the valley to the lake.
However, you had better be familiar with building wood RC airplanes, since the instructions, neither text or minimal drawings, aren’t going to be sufficient. Although most of the parts are numbered (sometimes milled in), not all are, and not all the numbers are referenced on the few drawings. This kit could use a diagram of the parts with their numbers. Even with the Multiplex stuff I sit there for a while contemplating it all, even more so with these kits. Well, the weather was kind of lousy that day anyway. It’s green here, because it rains, and snows.
Worse yet, I have two bundles, apparently for two airplanes, and only one set of instructions. I almost lost a little bitty folding propeller hinge pin in the grass out trying out a new airplane (that would have ended the flying session, and required the purchase of a new Euro14,50/$19- folding prop assembly to get another pin), he mentions that although a 4mm wing hold down screw would function, the included 6mm ones are easier to find if dropped.
One large omission in the instructions, what size servos? A goal here is to use what is on hand, left over from a similar sized Zagi THL (motorized) are a couple of pairs of HiTek HS-81MGs, they will do fine for the smaller Simply. I have some additional new servos in the (30) gram size, they will go in the bigger WHISS. The wing(s) is secured to the fuselage(s) with a single screw. The instructions show the servos mounted in the fuselage. What, they have to be disconnected and reconnected every time the wing comes on or off? No hardware I have yet had withstands that, it would be a nuisance every time, the picture in the catalog shows the WHISS servos being mounted in the wing. There is no linkage hardware in the package, but then those materials too are in old inventory. I’ll forgive a whole host of errors and omissions to get really good balsa.
I pulled up the web site, which included some magazine reports, one from the German language magazine Aufwind (z. English, updraft) that cleared up the choice of servos. Similar to my admonishment, the reviewing/builder/pilot admonished the readership to not (expletative deleted) around with the cheapest stuff, get decent servos. The designer, in consultation with the reviewer, reports metal gears as unnecessary. Maybe where he lands, but that little bitty patch of grass not far from the Rhine surrounded by wine grapes supported on wires interspersed with trees and crops means we are going to have to force the airplane into the grass sometimes, or shred the whole thing. We aren’t expecting this airplane to withstand the cartwheel landings of a Zagi, the designer is no doubt right, for his landing conditions.
All my slope airplanes wear servos with metal, or karbonite gears. We slope pilots stood there too often after a hard landing with an otherwise flyable airplane.
But the article did not clear up if the wing needs any ‘V’, or washout. After consulting with the airplane(s) owner, we decided to just build the first one straight up, as flat as possible (no washout (Schränkung)), and see how it went.
But every other wing, conventional or flying wing, I ever assembled required washout. It was almost too much washout, which guaranteed flying success in the original Zagi, that made it so easy to improve on. In EPP cores the washout is cut into the wing.
Even the man carrying airplanes have washout. One of my neighbors at Corona Municipal Airport in California, who spent four thousand hours and seventy thousand bucks (cash out of pocket, not including driving back and forth and so on, he had to learn a lot, he bought it all new) assembling a four seat fixed gear Lance Air. My standard fee for helping with your stuff is a large pizza with everything on it, get something for yourself if you are planing on eating too, Pizza Hut will not accepted as renumeration. I spent a few days helping him, dash wiring and landing gear. Since he thought I was a derelict it took a some convincing from the other pilots, who’s airplanes I’d also help build, and some desperation, to enlist my help. He recounted they forgot to put the washout into one of the reconfigured wings. The same as we RC builders, the fiberglass/composite moulds were designed to be cut flat (which greatly simplifies the programming for the CNC machine they are cut on and the requirements for manufacturing the mold), then twisted, they forgot to put the twist in one side. He has to send one whole wing back to the factory. I had a discussion with him, “fly this thing first” then get retractable gear, the turbo for the motor and pressurization for the cabin, at about the fifteen hundred hours of the journey.
When last seen he was desperately loading it all onto a trailer as Corona Municipal airport flooded. My father taxied the family Piper Pacer out onto the dike that is the access road as there wasn’t enough runway left to fly off of, even had the airplane been in license. We used to get the “reality TV” show of Barries Hot Rod shop on cable TV at my place, that dike is often used for photo shoots in the series.
But when it came to self stabilizing in the roll axis, I reconsidered. Flying a completely flat wing is a nuisance after twenty minutes or so, even the “all out” F3J thermal competition airplanes almost always include at least a degree or two of V. The advantage of not having to constantly concentrate on keeping the airplane flat, particularly way out there, and where we are going to be flying the far end of the slope can be a kilometer away, outweigh any theoretical slight reduction in efficiency. Put in Tan of 1 degree in a calculator for a numerical comparison of flat verses just a little stability. There is some V to build into the WHISS, which was to be the thermal wing for the Simpley (they take the same wing mount) and I thought about the thrilling fast slope airplanes of the past. The kind where they start at $400/Euro300-, plus radio and servos. After twenty minutes the pilots landed, their reactions tired. My flat wing Sturmoviks are fatiguing on lazy summer days with thermals to fly without some V. We are expecting flights from three quarters of an hour on up, the wings will get four degrees of V.
Luckily we still have two local hobby shops where flat servos (Dymond D-60 servos, their motors may be garbage, but word is some of the servos are fine. NO, not the gone missing dealer on Convoy in San Diego but a big RC mail order company in Europe.) can be ordered. I finally feel motivated to finish a conventional (both the Simply and WHISS are flying wings) thermal motor sailplane that’s been laying around for years.
The kit includes spruce leading edges, and parts to separate the wing halves of the (118) cm Simply’s wing. The spruce looks like long matchsticks, milled to match the airfoil. If the fit isn’t perfect, because wood is a natural material that, even if it were perfect at the time of milling, changes slightly with moisture content and in response to being cut out of the tree it once was, balsa kits have to be sanded some. In case you were wondering, I habitually sand even my Multiplex kits, it gives me some time to contemplate what I’m doing.
I made a basic decision that we have no difficulty transporting a wing a little over four feet long in one piece, lets save the weight, complexity, vulnerability and fumbling around at the flying site, of a split wing. Unlike the constructor back in Austria, we have no intention (yet) of putting the airplane in a backpack so we can carry it up into the hills, the wing will be a single piece. I often build two of the same airplane, if we need a separable wing, the second one can be so fitted out. If spruce leading edges, milled to match the profile (carbon fiber is a portion of a circle) are good enough for the designer, for this first pair of his airplane designs any thoughts of carbon fiber leading edges were put aside.
In case you were wondering, I estimate I gave up about three or four percent of both glide performance and top speed in my Fun Jet Lites by going to carbon fiber leading edges lapped with fiberglass. I used half circle 1,5mm carbon fiber, and (4) ounce per square foot fiberglass held on with the easily available here in Germany very low viscosity resin. In the vertical plane the carbon fiber is quite stiff, that’s when you realize that those oh so affordable Multiplex airplanes aren’t as straight as the moulds they were expanded foam into, I had to sand and fill. The aerobatics also suffered just a little from the blunter wing, although really abrupt maneuvers (high angle of attack) were a little better. The first time the friend it was given to hit a fire hardened burned bush (out looking for a place to slope soar out around Jamul), and all it did was break a control horn, he understood. The wing would otherwise have torn in half and the nose separated. Know anybody else who’s Fun Jets are still flying well at a hundred flights?
As entertaining as reading the designers book was, Schweissgut doesn’t land in fields of standing wheat, or get blown sideways by air currents we can’t sense from we stand to land on rocky farm access roads, we do. You can tell that from the unreinforced wing tips, they will come off on the first landing spin. He does mention landing once landing in thorn bushes (try Cowls Mountain, or the San Diego County Back County), but not trees. The friend the airplane belongs to recently spent an hour in a tree recovering a Twin Star II, wondering if he fell would he be able to use his cell phone. He had run the battery dead, when that swirl hit there was no motor thrust left to get out of it, in the confusion… Bought new in box prebuild, not treated to my usual reinforcement, the wings droop a little, and you can see the scars, but it still flies well.
Sometimes I just pick out a place that seemed interesting and make it a destination of a wandering, the Leck Valley is now on the list. Maybe on the way to Italy to look at that surreal capsized ocean liner near Rome. But I really prefer France. To afford the drive to Appenheim I have to carpool… Sometimes after the day riding around on a bicycle, I’ll sit there next to traffic an extra twelve minutes waiting for the alternate bus so the last kilometer, up a steep hill, costs Euro1,55/$2-, instead of Euro2,50/$3.25-.
I just went through $3000/Euro2400- and two months looking for work in Southern California, my wife and I are still in love with each other, my modest apartment includes a room for a shop in the basement, I have Euro400/$525- a month to spend as I please. I could do a lot worse. Listening in to a couple of guys my age bedding down next to the street in the Golden Hill district of San Diego a couple of months ago, they were clear headed and sober, evidently decently educated, defiatly not the “I’m a bum because I like it that way”, and resigned to that’s how it is.
The instructions recommend painting the airplane, or iron on foil. There are endless discussion of smooth or slightly rough flying surfaces, the designer notes that at the speeds of these two airplanes, it doesn’t make any difference. As for paint, fine, but the middle of the wing, the wing tips and the whole fuselage are getting a thin layer(s) of fiberglass with resin. Time consuming, the sanding of that glass hard material over a soft one doesn’t result in a “nice” finish, but necessary. I can build these two airplanes quickly for wow performance, for just a few flights, or armor them for the real conditions we fly under, and get a whole lot of flights out of them.
I have some left over iron covering, in blue, if the glue still functions. But I learned the hard way, do not make the bottom of your wing blue. Ask the owner of DW models about hitting a Zagi flying wing of mine from underneath with his far more valuable motor sailplane. The flight line thought it was an intentional act, they all cheared!
My Graupner Terry has foam a little higher density then the Simply’s balsa, even with fiberglass the fuselage bottom and underside of the wing are dented and scraped after “just” sixty flights. We fly in the winter here too, and the local molehills (hidden in the grass) include dug up rocks, sometimes the whole hill is a rock when frozen solid. As I noted in my book “So, You Want to Fly RC” my airplanes are better built and last longer then anybody else’s, because they have to. You could commit a mortal sin (eine Tödlichesünde) with my Sturmovik fuselages (or grave bodily injury with the Terry’s), the noses and bellies are that heavily armored. Nobody who ever received one of my reinforced Multiplex airplanes ever complained about the extra couple of hours of work or fiberglass, at least not after a few flights when they compared theirs with other used airplanes.
The constructor recommends a MEGA RC-400/15/7 on 3S LiPos with an 8X5 folding prop. From the Internet site of Bichlermodelbau, that is a (63) gram 28 mm diameter 915 kV motor that can be run at up to (14) amps on 2S to 4S LiPos. The plywood motor mount(s) supplied are drilled for the old Speed 500 bolt circle, they have to be reworked to fit. See that comment about really good balsa. At Euro50/$65- that compares with the same weight Robbe or Graupner motors, which have a bearing life of about sixty to eighty flights. With the admonishment that that combination can also be used with bigger airplanes. What I have in inventory is a Graupner @ (45) grams, that can also swing an 8X5 prop. A goal here is minimum Motor(izerung), we just want to get it up in the air at Appenheim and for an emergency altitude gain to get it back. Wait until my friend sees his airplane tumble, at half a mile, for no apparent reason, when a thermal adds to a rotor, and see if the motor wasn’t worth it. What luck, my Neumotors 3S 1100 mAh batteries exactly fit as do my reassembled 4S ones.
Unlike the constructor, who evidently from the photos in his book has wide open grassy places to put his RC airplanes down, easily seen from the steep slopes he flies on, we have two little patches of grass. And not mowed grass either, we are talking two or three feet high grown wild. Although we can see above the slope, visibility is restricted, we can neither see the face of the slope for the trees, or much behind us. The whole slope itself, as is almost, but not quite, all of the surrounding area, is either forest, or vineyards, air flow down near the slope is nasty unpredictably turbulent. Landing is point it into the wind and drop it, a try again is going to mean dumping the airplanes sometimes in the, we can’t see it from we stand, mixed forest below. Guess the glide into the wind wrong, land short, and it’s render the airframe in pieces when the “arester wires” of the vineyards stop it, spend hours finding it in standing corn, or slam it into either the asphalted farm access road, or it’s burm. Either that or stand there feeling helpless looking up, or down, at your investment hanging there in a tree. That’s after, or if, you find it.
At least we can drive right up to where we stand to fly. And it’s a nice view, out away from the big city, quiet, no jets from Frankfurt or traffic. Flying can also be time to contemplate.
What’s life, why are here?
Well come with us to fly on the breze up a slope
Should make that all clear
So let’s just float above Appenheim for a while
And be of good cheer
For slope soaring is part of our reason of life
We fly near the Middle Rhine,
But why here?
Beacuse this is where right kind of hill is
That much should be clear
And just what, what, what do we all fear?
Losing sight of that RC airplane
When it tumbles in clear air
To land shreding it through a vineyard,
Or be lost in the woods
Is what we above Jugenheim all dare
If it means writing off an airplane now and then, ok.
In respect to the finances of the airplane’s owner allow, what he needs is a Hacker motor and controller with Aero-Naut folding blades. A (45) gram Hacker, with it’s better everything (including magnets and bearings), puts out more power from the same input as a (63) gram “standard” motor. I have yet to meet anybody that wore a Hacker (or Neumotors) motor out. Half the chat in the Internet forums is people wondering why the’re stuff doesn’t work, badly informed by the magazine authors omitting by censorship the lack of quality control of the cheap stuff. Fortunately Hackers take the same mounting circle as any lesser brand. If we really want to wow the other pilots, we’d run a geared Neumotors in the bigger airplane.
A goal for us is slope soarers with no motors at all.
As for building with balsa, unless you wake up nights seized with a desire to build furniture, let it go. I didn’t have to dream that up, I personally knew not one, not two, not but three engineers with that desire. There might be some satisifaction in knowing that what’s flying up there you personally handcrafted.
There is no need for a detailed report on the rest of the construction, as noted in my book, there are plenty of sources for that already. The added fiberglass/resin/hardwood flooring paint added about (40) grams to the all up weight over and above a “standard” finish. About average when the designer quotes a weight for the glider version of (500) grams. No only does speed cost money, durability costs weight. It took up about two eight hour days to get the first airplane ready for testing. Not all at once, a few hours here and there on days when it rained. One developing problem, I started brewing my own Bier, it needs to age a while, and I store it in the basement workshop. Burp
Some clue about why, instead of just a seperate thermal wing, an entire second kit was included. The Simply instructions include drawings (poorly dimensioned, if the parts don’t fit) for both the slope and the longer wingspan thermal wing. However, the eight angled wing segments for the thermal wing (as shipped), are angled exactly for the six of the slope wing (the second kit just had two more center segements), they won’t fit, without some working over. And there aren’t enough parts to complete a second fueslage, and they don’t match. See above about, never again, sanding and Depron/fiberglass.
Ever wonder what it would be like to quit your mundane job and manufacture RC kits? Well, our own (current) SEFSD editor did. If I may quote him “somebody is always trying to ruin me”. It appears that Schweißgut made the decision to sell the mangled WHISS kits as wing components for the Simply and throw in the extra parts. See above, the locals are usually right.
For the servos, I just couldn’t put (20) gram (each) servos midspan in a wing where the bare halves weigh (64) grams each side. A hybrid solution was chosen, mount the on hand HS-65s (left over from a trashed Multiplex Dogfighter, what a twichey beast to fly) with the same rod/tubes we have all come to enjoy. Metal gears would be better, these centrally mounted into the wing ones can be changed if needed.
And there you stand at the flying field, that filigran, lightweight, joy to fly ARF slightly tweaked, knowing that human hands originally built it and that it should be repairable. See above, my standard fee.
See Part Two for the adventure of flying The Simply.