Oly II S Build log? [Archive]

cn0rris

Nov 12, 2008, 10:54 PM

All right, here goes, then.

This is my build log for the Oly II S. The "S" model is a bit different from the standard Oly II, in that it swaps the original flat-bottomed airfoil for a Selig S3014 airfoil and makes a number of structural changes to the wing, like adding a fully-sheeted D tube. The fuselage is slightly different as well to accommodate the different airfoil shape.

There are already a couple of good build logs for the standard Oly II, but I wasn't able to find any for the "S" model. So here's mine. I hope you enjoy it.

Since the standard Oly II build has already been documented very well, I'm going to focus more on the parts of the build that are different from the standard model. See these build threads covering the standard Oly II:

My Oly II Build (http://www.rcgroups.com/forums/showthread.php?t=450321)
Oly II Build ( http://www.rcgroups.com/forums/showthread.php?t=467160)

I suppose technically, this is not really a traditional build log, since I built the plane first, taking pictures along the way, and waited until I saw how it turned out before documenting it here. I'm formatting it as a build log because I like that format and getting to see the progression, and hear about the difficulties the builder ran into and how they solved them.

My intent is to have a mostly stock build, with only a few minor customizations. I'm building with spoilers, and the way I chose to set up the linkages is interesting (to me). I'm not doing the flaps, so this will qualify for my local club's RES competitions (the Torrey Pines Gulls). Both of those are included in the plans, so I guess they don't actually count as modifications from "stock", I suppose.

By the way, I don't consider myself a master builder by any means, so please don't consider this to be anything more than a record of how I built this plane. I don't pretend to know the best way to do anything, so if you're looking for master building techniques, please look elsewhere. I try to point out things that worked out well for me, and things that didn't, but I have no doubt that there are probably better ways of doing everything. If you have a favorite technique that works for you, please share it - I'm always interested in improving my skills.

cn0rris

Nov 12, 2008, 11:07 PM

I should mention I'm building the SkyBench kit (www.skybench.com (http://www.skybench.com)), and I've been very pleased with the parts quality and fit. This is my first build in over 15 years, and laser cut parts are one of the amazingly good things that have happened in that time.

Here's what the kit looks like in the box fresh from SkyBench and then with the plans and all the parts laid out. I always enjoy the anticipation of this stage of a build - there's something very cool about looking at all the parts and starting to visualize how everything fits together.

The kit is very clean and complete - even the pushrods and control horns are included. This being my first laser-cut kit, the slightly charred edges on the wood parts was interesting - I guess I just hadn't thought about the fact that it cuts by burning - duh.

cn0rris

Nov 12, 2008, 11:31 PM

I began by reading through the build instructions carefully, checking out the parts and trying to visualize how everything fits together. The build instructions are written by Bob Legue, and on the whole, I found them very good and complete. But as the build progressed, there were a few places that I found myself wanting to rewrite things to make them easier to understand. I'll point the problem areas out as the build progresses. To be fair, it might be just me - I've built 5 woodies in my life, so I'm moderately experienced, but someone else might find the instructions perfectly adequate. To me, they felt like they were written by someone with tons of experience building, who "just knows" what to do and doesn't necessarily realize what problems someone without so much experience might have. Maybe this build log will help you avoid some of the problems I ran into. Wherever possible, I would recommend dry-fitting the parts to make sure everything fits where you think it is supposed to go.

The instructions started with the empennage, so I began there. You've got to start somewhere, it was getting late, and I wanted to get something gluing so I could feel like I had really begun the build. So I glued up the horizontal and vertical stab parts and left everything pinned to dry overnight.

The empennage is one of the differences between the standard Oly II and the Oly II S. The "S" has solid balsa empennage parts, which seem like they would be much heavier than a built-up version. I kept with my plan to build stock, though, and resisted the urge to scratch build built-up tail feathers. They certainly look much stronger than a built-up model, so if I flip on landing sometime I may be very glad of the extra strength. We'll see if the extra weight turns out to be meaningful for me when I get it all set up and ready to fly.

A bit about me - I'm getting back into RC sailplanes after about a 20 year hiatus wherein I went to grad school, got married, had a family, and developed in my career. Life intervened, so to speak, as many modelers can probably relate to. So I would still classify myself as perhaps an advanced beginner pilot. I've probably actually spent more time building than flying, but I hope to rectify that over the next few years. It's likely that I'm going to be very glad of those stronger tail feathers when I land it hard some time.

cn0rris

Nov 12, 2008, 11:39 PM

Although the plans do the fuselage next, I decided to build the wings first. They're the most interesting to me, and I prefer to build the fuselage in parallel with the wings, usually while something is drying.

You start by laying the leading and trailing edge sheeting over the plans, and using the ribs to set the spacing exactly right. Then you glue the bottom spar to the bottom front sheeting, weight down, and let dry. This is where I first ran into an area where I felt the plans could be more clear. You have to notch the top and bottom spars to leave clearance for the ply join tip joiners, as shown in the picture below. The amount of notch wasn't clear to me, though, even after checking the plans and reading the instructions carefully. My first attempt ended up with the notch too deep, but fortunately the kit came with extra long spars, so I could just cut off the mistake and try again and still have enough to complete the spar. For the record, the notch should be the same depth as the thickness of the ply tip joiner. I just used a razor saw and razor knife to cut them and they turned out fine.

The next photo is after I've glued down the bottom spar, and have weighted it to dry. Yes, I used canned green beans as weights for this build - I don't have any lead weights, and I could only find lead shot in 25 pound bags for nearly $60 around here, so I just used what was handy (and cheap). They seemed to work fine for the most part, but there were times when I think the extra density of lead would have been helpful. If anyone knows of a cheaper source of lead shot or weights in the San Diego area, I'd like to hear about it.

The second spar is just being used to help prop the green beans level.

One build tip - I found that after the wings were done, the joint between the flat inner panel and the leading and trailing edges wasn't as flat as I had hoped. At the seam, there was a bit of offset. Somehow when fitting them together, they didn't end up perfectly flat, and when I CAed them together, there was an offset. I just used my fingers to hold everything tight while I glued, and I think next time I'm going to pin everything down tight and give extra attention to holding things very flat while I'm gluing.

Enough for tonight - documenting builds is more work than it seems.

cn0rris

Nov 14, 2008, 12:40 AM

Next, I laid out the rest of the inner panel parts dry to see how everything fits. Laying the ribs out exactly on the plan, I found that the 3/8" shear webs aren't quite long enough in some cases. Even if I fudged the rib locations around a bit, I couldn't get them to fit correctly, so I just filled the gaps with small pieces of balsa.

Since I'm building the spoilers, I also laid the spoilers and sub-spars on the ribs to see which ribs I needed to trim. Then using the spoilers and sub-spars as patterns, I marked the ribs that needed trimming and cut them to fit using a razor saw and knife.

cn0rris

Nov 14, 2008, 12:43 AM

Then, I glued the ribs and shear webs in, using wood glue for the shear webs, and CA for where the ribs contact the sheeting. There was no particularly good reason why I used CA for the rib/sheeting joint, but it just seemed easier to just wick in the glue. Plus it ensured that the ribs were tight to the sheeting. Then you dry fit the top spar and weight everything to keep the pressure on while the glue sets.

One problem I ran into though. I built using Titebond glue for the first time, instead of my usual Elmers wood glue, and it seemed to set up quite a bit more quickly than Elmers. I was taking my time, making sure everything was lined up, and adding small balsa bits where the shear webbing wasn't quite long enough, but before I finished, the Titebond was already starting to set up in the pieces I placed earliest. I had to hurry and get the top spar on (you fit it dry to apply pressure to the shear webs) and get my weights on before it completely set up. As a result, my top spar ended up a bit high in some spots, and later I had to spend quite a bit of time trying to sand it back down. Not fun. The second wing went fine - lessons learned.

cn0rris

Nov 14, 2008, 12:57 AM

Next, it's time to pull the bottom sheeting up to the ribs (they're not flat as on the standard Oly II wing) and glue them with CA. The instructions recommend shimming them up with something long and thin, but another Torrey Pines Gulls member who is a couple of weeks ahead of me building this same model warned me that he wasn't very satisfied with this method - it was hard to get the bottom sheeting fully in contact with the ribs, resulting in gaps that distort the airfoil a bit. So I used a method I learned with earlier models and just used my fingers to pull the sheeting up to the rib and hold it while I wick in CA. To make sure I didn't accidentally build in any warp, I first pinned the wing down to my board with the rear flat portion firmly attached to the table, and the forward section hanging off the edge. This allowed me to easily curve the sheeting with my fingers while gluing. I was very happy with the results.

The second wing was pretty much identical to the first, except I managed to get all the shear webs and ribs in place before the glue dried. Rather than pulling up the plans for the left wing and pinning on the right one, I just built the right wing on top of the left wing plans, only rotated 180 degrees. The rib spacings are the only things I really needed from the plans, so that worked out fine.

Notice that in this picture, the spoiler sub-spars are already installed. This was a big mistake. I thought I was saving time, but it ended up causing quite a few headaches when it came time to clamp the plywood wing reinforcements to the spar (W1 through W4). I managed to clamp around the sub-spars, and everything turned out fine, but I had to make some special clamping pads to allow my clamps to apply pressure correctly. It was a real pain, cost me a lot of time, and would only have saved me a few minutes even if it had worked out the way I hoped. I think I mentioned I wasn't a master builder... ;)

cn0rris

Nov 14, 2008, 01:11 AM

A little more detail about the ply W1-4 pieces. These surround the wing jointer tubes and tie the bending load out along the main spar and to the rest of the wing. You use a Zona or Exacto-style saw to cut through the ribs to make room, and it's important to make sure you don't torque the ribs downward by making the space too small, which would droop the leading edge of the wing. This took quite a bit of trial and error with the saw, and in retrospect I realized that my Perma-Grit sander would probably have made this a lot easier.

When it came time to clamp in the W1-4 pieces, I really regretted installing the spoiler sub-spars early. I had to do some jiggering with clamps, and make some clamping pads to get clamps applying force correctly.

After the front ply reinforcements are installed, you install the wing joiner tubes and tack them in place prior to epoxying them in permanently. This is another of those places where the instructions are a bit light for people who like more detail in the instructions. To make absolutely sure the center dihedral was set correctly, I blocked up both inner panels to the appropriate height, leaving the joiner tubes and rod installed, but loose. Once I was really sure the dihedral was right and the joiner rod was level, I clamped the tubes in place and used thick CA and kicker to make sure they didn't move until after the epoxy was applied. You need to be very sure at this step that the brass joiner tubes stick out from the wing root beyond where the ply inner rib will be applied later. The tube will get sanded down to match exactly later, so as long as it's hanging out enough, the exact amount isn't critical. Unfortunately, I didn't get pictures of these steps (documenting builds is harder than it appears!), but I think words paint the picture adequately. This really worked out well, and I wish the instructions went into more detail about this step, as it determines one of the fundamental angles of the wing.

Once everything is tacked up and set correctly, you set each inner panel on it's nose and fill up the space around the brass joiner tube (between the upper and lower spar caps) with an epoxy and micro-balloons mix. This locks the joiner tube into a very solid assembly with the spar caps and the ply W1-4 pieces, and it seems very strong. I really stuffed the cavity full of epoxy mixture so that when I added the rear W1-4 pieces and clamped them in place, small amounts squooshed out in a few places. I took that as a good sign that the cavity was completely full with no air gaps. A small amount of cleanup after it was clamped, and then with a razor knife after curing was all it needed.

cn0rris

Nov 14, 2008, 01:18 AM

Leaving the inner panels curing, I built the two tip panels. They go together pretty much the same as the inner panels because they have the same construction. The shear webs are a bit different (lighter), using only thin webs applied to the outside of the spars. This saves weight.

cn0rris

Nov 15, 2008, 12:11 AM

Next, I prepped to add the top sheeting at the trailing edge. To do this, you first sand the trailing edge sheeting down to a point, matching the line of the ribs. This allows you to overlap the top trailing edge sheeting neatly.

You do this by pinning the wing with the trailing edge lined up along the edge of your building board, and then using a sander to taper the bottom sheeting. I applied packing tape over the ribs to protect them from the sander. It worked really well. It gives you plenty of warning that you're in danger of sanding a rib, and if I sanded through the tape, I could just replace the piece. I found that my PermaGrit sander worked best for removing the material quickly, and then I switched to finer sandpaper to finish the job.

Also, I forgot to mention that I attached the tip joiner to the inner panel earlier than the plans call for - it just seemed like the right time so I could make sure it was aligned carefully. It worked out just fine.

cn0rris

Nov 15, 2008, 02:33 AM

Once everything was prepped, I glued on the top trailing-edge sheeting. To keep everything really flat, I used a nice aluminum straight-edge I bought to use for cutting plywood. Very straight and flat, plus it has some nice ridges to hold the green bean cans... ;)

Worked great - the trailing edge came out nice and straight.

This construction of trailing edge is different from what I've built before, and I really like it. It seems much sturdier and lighter than a trailing edge made of traditional "trailing edge stock." The ribs extend into the trailing edge maybe an inch, so there is a lot more glue surface, and it really knits the structure together.

cn0rris

Nov 16, 2008, 07:59 PM

Next, I attached the wing tips to the inner panels. First you have to sand the tips to get the correct angle on the spar, and the bottom sheeting. I've always free-handed this on the few planes I've built, and it always turned out fine. It was a process of sand a bit, try it, sand a bit more, try it, etc. But recently, I read a description of a method I like a lot better and will try next time:

This method works if you have a building table with enough of a square edge that you can run a sanding block along it and maintain the square angle with the sanding block. My table is a door panel, so it's got perfectly square edges with enough thickness to work with. You pin the wingtip panel to the table with the tip blocked up to the correct height and the root end hanging over the edge of the table just enough. Then you sand it off flat and even with the edge of the table, and it's perfect. At least it sounds like it would work great - I'm going to try it with my next build.

I mentioned that I attached the tip joiners to the inner panels, and that really seemed to make things easier because it gave me a ready reference for the angle I was going for as I prepped the tip panel to match the center panel.

A final note - I glued the first panel (with epoxy) at an angle that seemed about right, matching the tip joiner. But for the second panel, I mounted the first panel tip-to-tip with the second and made absolutely sure that the second tip was exactly the same height as the first.

cn0rris

Nov 22, 2008, 09:51 PM

Next, the top sheeting is attached. The build instructions suggest using wood glue on the spar and rib tops and taping things down as in the pictures below, then weighting it while the glue dries. But I this worked out very badly for me - almost to the point where I thought my wings were ruined. Somehow, despite my taping and weighting efforts, the top sheeting didn't make firm contact with the ribs in several places, leaving the top sheeting unattached to several of the ribs after the wood glue dried. I was rather panicked at this point, because at this point the wing is closed up, and you don't have easy access to the inside to fix anything.

Fortunately, I was able to repair things by rigging up an extra long thin CA tube which could reach well into the wing through the gap where the leading edge will be attached. I first trimmed back the top & bottom sheeting to expose more of the gap (not so far back that it would interfere with the sanding needed to prepare for attaching the leading edge piece) and then using my fingers to press the sheeting against the ribs, wicked in CA to make the joint. It wasn't the easiest thing, but it worked.

Doing a post-mortem on the problem, I think my problem was that I did an inadequate job applying pressure to the curved surface of the top sheeting. I weighted the back of the sheeting at the top spar using my straightedge and canned green beans, and thought that the pressure applied by bending the top sheeting over the ribs (held with tape) would be enough to make firm contact all along the ribs. But this obviously wasn't true, and when I do this step on future builds, I'm going to use lead shot, BBs, or maybe pea gravel (as suggested somewhere else in RCGroups) to apply more firm, even pressure along the curve of the ribs. Also, using a slower-setting glue like Elmers might be useful as well, to give me time to get all the weights in place.

cn0rris

Nov 22, 2008, 09:57 PM

After the problems with the inner panel top sheeting, I used the hand method of holding the sheeting with my fingers while wicking in CA. You risk gluing your fingers to the wing as the thin CA wicks through the veins in the wood, but so far I've always been able to peel my fingers free. :)

This worked out very well, and seems likely to be lighter as well. Maybe I'll use the same method for top sheeting in general next time.

The tip sheeting in this SkyBench kit comes pre-cut with the curve necessary to make it match the joint with the center panel. Very nice. Minimal sanding was required.

cn0rris

Nov 22, 2008, 10:25 PM

Next, I assembled the fuselage. The Oly II S fuselage is virtually identical to the standard Oly II fuse, as far as I can tell (I haven't built a standard one), so I don't need to go into as much detail. Which is handy, because for some reason I didn't get as many good pictures of the fuse build. :) I imagine only the wing saddle is different to match the S3014 airfoil instead of the original's flat-bottomed one.

First you join the front and rear parts of the fuse bottom. I used wood glue, aligning the two carefully along the centerline. To get it exactly aligned, I marked the centerline at several strategic places on the front and half pieces, and then aligned them using a straightedge. Some people align them over the plan, which I'm sure works fine too. Once it was aligned, I pinned it down firmly using crossed T-pins to keep it flat.

cn0rris

Nov 22, 2008, 11:21 PM

With the bottom drying, I assembled the fuse sides, constructed out of a sandwich of three parts - two balsa (one thick, one thin), and a very thin plywood doubler. The plans weren't really clear about the order of the pieces. But by carefully inspecting the arrangement of holes you'll see there's only one possible way to assemble them and still leave the slots for the former tabs clear. From the outside in, the order is: thin balsa, thick balsa, thin ply. My advice is lay it out dry until you're sure of the arrangement. That's just good advice to live life by, I guess... ;)

The sandwich is assembled using epoxy, since white glue would tend to warp the balsa. It also makes for a very strong sandwich. It actually requires very little epoxy - you scrape it on very thin and weight down well so the glue makes good contact with both pieces.

Attaching the front and back fuse sides, you lay them out along a straight-edge. Another benefit if the absolutely flat fuse bottom.

The result is two very strong fuse sides.

cn0rris

Nov 22, 2008, 11:53 PM

With the sides and bottom assembled, it's time to put it all together. The bottom of the fuse is perfectly flat, and the fuse sides overlap the bottom. You attach the formers to the bottom first, exactly at 90 degrees, making it really easy to get things lined up perfectly with a simple square.

I used wood glue to attach the formers. To make sure the bottom stayed absolutely flat while assembling the fuse, I cross-pinned it firmly to the building board.

A couple of mistakes I made that I will avoid next time. First, because the nose block is slightly tapered, the glue acted as a lubricant and under the pressure from the clamps, it slid about 1/8" inward, and I had to use my X-acto saw to notch the nose block back so the hatch cover would fit. I think a pin or two at the rear of the nose block would prevent it from shifting.

The second mistake was trying to insert the plywood tail reinforcement piece along with everything else. The build instructions say to install this later, and I would recommend it. Mine ended up slightly twisted without my noticing it. It didn't seem to affect the straightness of the fuselage, and I sanded it back flat before attaching the empennage, so no harm done.

cn0rris

Nov 23, 2008, 12:15 AM

At this point, I ran into the only problem with the kit parts that I found.

The balsa fuselage top runs from the rear of the wing saddle (there's a spruce stick just aft of the wing, too) to the front of the horizontal stab. But the notch in the fuse sides appears to extend about 3/8" too far forward. If you seat the empennage in the notch, as seems to make sense, it is so far forward that the rudder clips the end of the fuselage. The length of the fuse top seems to be the correct length. It wasn't a big deal - I just filled in the gap with some scrap balsa and all was well.

Please don't let this give you the impression that the kit isn't absolutely great. This kit is excellent - the parts are a wonder of accurate cutting, and fit together like Legos. This is my first build since laser cut parts came along, so maybe this is the norm now, but in my opinion Ray Hayes at SkyBench has put together an absolutely wonderful kit that is a joy to build.

cn0rris

Nov 23, 2008, 12:43 AM

At this point, I have all the major components complete. Empennage, wings and fuse. Time to install the spoilers.

These are the first spoilers I've ever installed, so it took a bit of reading and figuring to get the linkages working the way I liked. I first made a little servo "shelf" to hold the servo. It's actually on the top of the servo - not the bottom, but that's fine because it's glued in anyway. The shelf is mostly there to give enough surface area for a solid glue joint. I used HiTec HS-55 servos because they're inexpensive and light, and other reading I had done seemed to indicate they had enough power for the job (they do - flight testing has been fine).

For the linkage mechanism, I used a Dubro Micro Pushrod kit for the raw materials. A short (1") piece of the plastic pushrod sleeve made a nice bearing on the underside of the spoiler. I attached it firmly with a small piece of fiberglass glued in with thin CA.

The metal pushrod itself was the raw material for the z-bend linkage connecting the pushrod sleeve bearing to the servo arm. The pushrod has enough flexibility that you can bend it to get it into the servo arm, but it springs back nicely holding everything together. I wish I had gotten a picture, but there are only two bends in the linkage - one where it goes into the spoiler bearing, and one where it goes into the servo arm. The bends are in opposite directions, so once it's installed, there is absolutely no tendency to slip out.

In the last picture, you can see that the linkage has a bend at the midpoint. This was to shorten the linkage length a bit to get the spoiler to close fully when the servo is at it's "down-most" position. It doesn't serve any other purpose than to shorten the linkage.

cn0rris

Nov 23, 2008, 12:44 AM

One last note about the servo linkages. Either I got really lucky on this, or Z-bend servo linkages are simpler than they look. This was the first time I had built one from scratch, and I was worried about being able to get the length exactly right. But I found that by just eyeballing it, I was able to get them close, and then using the "bend it in the middle" technique, I was able to adjust the length very accurately.

cn0rris

Nov 23, 2008, 12:55 AM

As you can see in the pictures, I soldered the servo connection instead of using a plug-in extension. This has two advantages, to me. First, the holes for running the wires are smaller and neater (and might be more structurally sound - maybe?). Second, I trust a soldered joint more than a plug. Plus, as a bonus, I can make the wires exactly as long as I like.

All joints have heat shrink for insulation and structural support.

Note to self - next time, run the servo wires while the wing is open. It was a real pain working with a needle file to open up the holes in the fully sheeted center section for the servo wires and fishing the wire through the holes.

cn0rris

Nov 23, 2008, 01:05 AM

I wish I had gotten a picture before covering. There's something about the bare balsa structure that is beautiful to me. But I didn't, so here are some shots of the final product.

The "harlequin" color scheme has functional purposes, aside from looking good (I think so, anyway). "Right is red" no matter which direction it's going, which comes in handy every now and then, at least for me. More experience pilots may smirk, but it's been helpful a couple of times already. ;)

The black underside is to accentuate the contrast with the light sky. Since no matter what color you use for the underside, it always ends up looking dark at altitude, I decided to go all the way to black and make the contrast as high as I could.

cn0rris

Nov 23, 2008, 01:34 AM

Although I've built a few planes now, this is really effectively only my second thermal plane after my Gentle Lady. I've flown it on two separate mornings now, and I'm really enjoying the performance improvement over the Gentle Lady. I've got a number of flights under my belt now, and although it took a little getting used to, I can say that I love the way this plane flies. It penetrates in wind much better than the GL, has a flatter glide slope, and the larger size makes it easier to see farther away.

"Penetrating better" really just means "flies faster", which took a little getting used to. The Oly can slow down very nicely when you want it to, but even so, its stall speed is a bit higher than the GL. But I learned to keep my speed up on downwind legs flying the GL, so it hasn't been a problem. Stalls with the Oly are very gentle; they seem even more gentle than with the GL, if that is possible.

One characteristic that took me a bit of time to get used to was how it turns. With my Gentle Lady, I would exit from turns by letting up on rudder pressure - it would come out of the turn on it's own. With the Oly II S, I've found I have to add some opposite rudder to exit from turns.

At first, I thought I may have had something set up wrong. But what at first seemed like a flight quirk, I've realized is a real asset. With the GL, maintaining the turn with rudder means that rudder is adding drag. The Oly's rudder is much more centered while in a turn, which means it's adding less drag and is therefore more efficient in turns. I imagine this is old hat for some of you more experienced pilots, but it was a real "a hah!" moment for me. Another way of saying this is that the GL is extremely "stable" in turns, and will recover when you let off control input. But the Oly is more neutrally stable in turns, which gives it better performance in turns.

This plane is genuinely a sweetheart, really. It turns beautifully, recovers quickly from stall, and doesn't seem to have any unfortunate faults. It's a real joy to fly.

I can strongly recommend this particular SkyBench kit, and I'm sure that carries over to other SkyBench products as well. I tend to enjoy building nearly as much as flying, and I'm already looking around for my next project. I've always loved the lines of the Bird of Time... And the Windfree XL sure looks nice - flaps and ailerons would be fun.

equest

Nov 23, 2008, 08:35 AM

cnOrris,

Nice pics and what a great build. Great update on the building process and I am glad to see the maiden went well. Thanks for sharing.
Equest

merlinmurph

Nov 23, 2008, 10:28 PM

Sure, now someone comes up with an Oly 2S build thread. :o

My Oly 2S is my first large sailplane build, and it has been an adventure. I could write a book about all the screwups I've made - some small, some huge. But. this was supposed to be a learning experience. :D I laugh every time I read that Bob Legue built his in about 8 hours.

Enjoy your Oly!

Murph

atmosteve

Nov 23, 2008, 10:58 PM

Like the colour scheme, great build log and pics, thanks for sharing.
Had a go with any spoiler braking yet?
Steve.

merlinmurph

Nov 24, 2008, 12:36 PM

cn0rris,

Did you have this issue (http://www.rcgroups.com/forums/showthread.php?t=841078) where the 3/8" shear blocks were 1/16" longer than the vertical grain shear webs?

Just curious.

BTW, thanks for the heads up with the top sheeting and spoilers. I'm just about to do that.

Murph

cn0rris

Nov 24, 2008, 02:38 PM

I didn't have this exact problem. My shear webbing didn't fit exactly, but I just cut and filled in where it needed.

Chuck

cn0rris

Nov 24, 2008, 02:41 PM

Like the colour scheme, great build log and pics, thanks for sharing.
Had a go with any spoiler braking yet?
Steve.

Thanks Steve. The color choice seems very visible, and I'm happy with it. The "right is red" queue is helpful sometimes too.

The spoilers work very nicely. I've never flown with them before this plane, so I don't have a lot of experience, but they definitely bring the plane down when deployed. Nice and straight ahead, too.

I plan to get into thermal duration contest flying, and I expect they'll be quite useful for making spot landings.

cn0rris

Nov 24, 2008, 02:48 PM

I laugh every time I read that Bob Legue built his in about 8 hours.

I think if I had two or three Olys under my belt, I could finish much faster - maybe not 8 hours, but I'll bet it would feel pretty speedy. Bob's a very experienced builder, I imagine, and he's not going to go making the sorts of mistakes I made that took a lot of time to correct.

Some day I'll have enough time to get as much experience... ;)

Jim Deck

Nov 24, 2008, 07:21 PM

c0norris,
A very nice job indeed. Your servo installation is an excellent example of the KISS principle. I know you'll enjoy your OLY II for a long time.
Jim Deck

tunabiker

Nov 24, 2008, 07:57 PM

Great build log. Thanks for all the advice and experiences. Your plane is beautiful and I'm envious of your attention to details...probably my biggest lesson!
Bill

cn0rris

Mar 12, 2009, 02:43 AM

I've received a few inquiries about how I set up my spoiler installation, so I'm going to post some more information about how I set it up. The installation turned out to be pretty simple, with no complicated linkages, and now that I've been flying it for a number of months, I think they work really well. The only drawback is that mine don't quite lift up to a full 90 degrees.

My drawing of the geometry shows it should be able to get to a full 90 degrees, but I must have shifted the servos a bit, or attached the bearing to the spoiler blades at a slightly different spot.

Anyway, they work just fine, so I don't think it's critical.

cn0rris

Mar 12, 2009, 03:16 AM

Here's the drawings I made of the servo geometry to make sure it would work the way I wanted to. I hope this makes sense. It shows the spar, the top and bottom sheeting, the spoiler sub-spars, and the servo and linkage.

The servos are glued in, not screwed into a mounting post. I wrapped the servos in packing tape first, and used thin CA to attach them. The theory is that if I need to replace a servo, the tape will help get them loose. But I think they're so-well stuck, that I'll probably damage things getting them out anyway. At least I can peel the old CA glue off the servos with the tape...

I made the linkage out of a piano wire pushrod assembly I bought at the local hobby store - the thinnest they had. It came with a plastic sleeve that you can use to make a perfect bearing tube for the spoilers. I just cut off a bit of the sleeve the right length and then used medium CA with kicker to attach it to the spoiler blade. Then I put a small patch of light fiberglass over the bearing and used thin CA to bond it to the blade and the tube. Without the fiberglass, the joint was a bit weak, but with it, it's rock solid.

The linkage itself was made from the piano wire, bent with needle nose pliers, just eyeballing it. I had to make a couple before I got it right, but there is quite a lot of pushrod material, and you only need maybe 2 inches for each linkage, so I could make a couple and see which fit the best.

What must be an old trick that I re-discovered on my own; if your linkage ends up slightly too long, you can just bend it, effectively making it shorter. In fact, my next build, I'll probably start with it slightly bent - that way you could straighten it some to make the linkage slightly longer, or bend it more to shorten it.

Mounting the servos in the open part of the bay means you don't have a lot of surface to glue to, so I made a bit of a shelf out of balsa to attach the spoiler to. The shelf is glued to the spar in the front, and one rib on the side, so it's pretty strong. I reinforced the "floating" edge of the shelf with an extra piece of balsa, which hopefully you'll see from the drawings.

cn0rris

Mar 12, 2009, 03:21 AM

I hope this helps. It's really quite simple when you look at it in person, and I like it very much for that reason. I hope the drawings help clarify things, along with the photos of the servo installation from earlier in the thread.

I should have noted above that I used Hitec HS-55 servos, so my geometry is sized for those. But you should be able to make any servo that is small enough work.

I originally worried that the HS-55s might not have enough torque, but it seems to work just fine.

Chuck

cn0rris

Mar 12, 2009, 04:00 PM

I forgot to include this picture showing a bent linkage. The cool thing is that a bent linkage is exactly the same as a shorter linkage, if you neglect any possibility for flex in the linkage around the bend. And for short links like this, that's definitely true.

So you can adjust the length of the linkage by changing the bend. This makes it easier to adjust the spoilers exactly where you want them using two needle-nose pliers to change the bend angle.

wingsnapper

Mar 12, 2009, 05:38 PM

One characteristic that took me a bit of time to get used to was how it turns. With my Gentle Lady, I would exit from turns by letting up on rudder pressure - it would come out of the turn on it's own. With the Oly II S, I've found I have to add some opposite rudder to exit from turns.

At first, I thought I may have had something set up wrong. But what at first seemed like a flight quirk, I've realized is a real asset. With the GL, maintaining the turn with rudder means that rudder is adding drag. The Oly's rudder is much more centered while in a turn, which means it's adding less drag and is therefore more efficient in turns. I imagine this is old hat for some of you more experienced pilots, but it was a real "a hah!" moment for me. Another way of saying this is that the GL is extremely "stable" in turns, and will recover when you let off control input. But the Oly is more neutrally stable in turns, which gives it better performance in turns.

Holding turns like that is a prime example of both good design and builder's attention to detail.. I've stated for years that I didn't know what I was missing untill I flew one of Ray's Birds. Try bumping the cg aft a bit and I"ll bet you don't even have to hold the nose up turns either.. maybe a nudge or two here or there to keep the old bird honest.
Looks great man.

GDbot

Mar 12, 2009, 06:08 PM

This has been a great build log, thanks c. Just in time with your spoiler installation since I have to start thinking about my OLY 3 in the next few days. Again, thanks!, you did a great job on this build and posting it all here.

cn0rris

Mar 12, 2009, 06:37 PM

Thanks guys! This build has been rewarding both because the Oly II S is a joy to fly, and also because of the great community here on RCGroups.

atmosteve

Mar 12, 2009, 06:48 PM

Sounds a bit like its big Oly brother, a very accurate and very easy performer!

Those diagrams you made are very good, I hope the new builders out there can find them to help explain the levering mechanism and its principle for spoilers.

Thats the O2s in your avatar?, looks snazzy and easy to see at altitude, here's to you getting plenty with it.

cn0rris

Mar 12, 2009, 09:06 PM

Thats the O2s in your avatar?, looks snazzy and easy to see at altitude, here's to you getting plenty with it.
That's the one - thanks! I've been getting in a lot of flying time, both slope and thermal, plus starting to compete in thermal duration competitions with the local flying club, the Torrey Pines Gulls.

That reminds me of a subject I had meant to update the thread about earlier:

My personal experience backs up the strength of the SkyBench stock wing (no extra carbon or other extra reinforcement). I've recently been learning how to winch launch with the club winches, and at first I kept trying to be too careful with it and screwing up the launch. Trying to tap too much, I ended up not giving it enough juice to have a good launch.

Finally, I took the advice of an experienced club member who said "keep your foot in it until you're well past rotation and things look good". Well, my inexpert foot turned that into pretty much a full pedal launch the whole way up. But the wing hardly flexed at all, and I had by far the best launch I have ever had off a hi-start or winch, or anything. I even got a bit of a ping at release, and turned the extra altitude into making my 9 minute task on that round.

So now I'm much less worried about treating it gingerly on the winch.

Chuck

Ron Sickler

Mar 14, 2009, 12:52 AM

Great build thread == I was starting the"OLY2S" == when my "AVA" came in the mail == OLY back to the box == "AVA" is now finished ==Monday the "OLY2S" will be back on the bench.

I am VERY glad things worked out the way is has since reading this thread the build will go better. thank you for the information

"WOODY" ==== ron

Ray Hayes

Mar 14, 2009, 08:22 AM

Chuck,

OK to put your OLT ll S spoiler linkage drawings/text on my web site? They are awesome and will be very helpful to other builders. The bent wire idea is great.

As you become more experienced flying your OllS, use Wingsnapper's suggestion, you will be able to make flat circles with just rudder input and you will discover more thermals. Pilots that set the balance point forward because it is easier to fly ( plow jockeys instead of thermal hunters ) miss a lot of thermals. I get a kick out of new guys watching my planes fly, they invariably say ... wow ... your plane shows every little thermal. It takes practice and perserverance, but a lot of contests are won making the last couple of task time minutes flying below 100 feet working the small bubbles. The other common mistake and consequently bad flying habit is flying sailplanes too slowly. The faster you fly, the further back the balance point can be set. Enjoy ...

Ray
Sky Bench
http://www.skybench.com

cn0rris

Mar 14, 2009, 10:58 AM

Ray,

You're quite welcome to use them. I'm glad to see other people getting some use out of the drawings I just did to figure out the geometry I wanted to use. I can send high resolution versions if you're going to use them in print.

Chuck

Ray Hayes

Mar 14, 2009, 11:22 AM

I can send high resolution versions if you're going to use them in print.
__________________________________________________ _________

Chuck, that would be terrific, thank you very much.

Ray
Sky Bench
http://www.skybench.com

cn0rris

Sep 26, 2009, 06:44 PM

I just wanted to update this thread now that I've been flying my Oly II S for nearly a year now. In the past year, I've finished my LSF level 1, competed in several contests, and flown my Oly for many hours. It takes nearly full-pedal launches on the club winches just fine. I've thoroughly enjoyed it, and expect to continue flying it for years to come.

I think it was Ray who suggested I keep an eye on the rubber bands, and I can second that. The only damage I've had to repair was result of a winch launch into a stiff breeze. The Oly moved in crazy ways I've never seen before and I popped off low and landed moving fast with one wing low, bending it up a bit. I later realized I was using less-than-fresh rubber bands, and the wing had lifted off the fuse a bit.

Having built the plane, fixing it was pretty easy. I just removed the covering for a few rib bays, pushed things back into position, and a little CA and scraps of balsa for reinforcements, it was ready to cover again. After covering, it looked and flew like new.

Thanks, Ray, for making all this possible with your kit.

Chuck

smitty14

Sep 27, 2009, 10:10 PM

Hey!
I just got down one wing panel for the OLYIISe on Friday night. Still have to glue on the spoilerbearing. The Fix the gap in the center section by shimming a hand shaped piece of ply rib - for some reason I ended up with a gap? Top LE sheet, LE's and tips to finish the wings.
Slope soaring was not the best here with the wet , cool summer. I just had some other family/life issues get in-between the OLY build. I am looking forward to working on the OLY again. Those long wings just look cool when you slide them together.
Thanks for the update - Glad to hear you are having fun flying the OLY.

skypup

Oct 19, 2009, 02:30 PM

Then Fix the gap in the center section by shimming a hand shaped piece of ply rib - for some reason I ended up with a gap?

I ran into the same issue. I didn't when I built the original. To fix the gap I covered the left root rib with monokote and cut out the wing rod and alignment pin holes with a #11 exacto blade. The monokote is to keep glue from sticking. I applied lithium grease to the wing joiner rod and alignment pin to keep glue from sticking. I joined the two panels and applied a strip of tape to the top of the wing at the left and right root ribs. I then applied a strip of tape over the wing gap on the bottom where the wings join. This acts a dam to keep glue from leaking from the bottom. I mixed 30 minute epoxy with micro balloons to make an epoxy paste. The paste is applied into the wing gap from the top. Allow to gel. The epoxy sets up much faster with the micro balloons mixed in. I used my blade coated with lithium grease and cut between The left monokoted root rib and the micro balloon gap filler. This allowed me to separate the panels leaving the gap filler on the right root rib.

cn0rris

Oct 19, 2009, 02:55 PM

bbbp

Oct 19, 2009, 07:01 PM

skypup

Oct 19, 2009, 08:08 PM

I have an Olympic (88) 99 kit someone gave me 25 years ago. The only piece built is the HZ stab, which is slightly warped.

How does the Oly 99 compare to the Oly II or III as far as flying and sturdiness goes? Is it worth trying to construct this airplane from an old kit that has been stored in a Phoenix garage for 25 years (recorded summer time temps in the garage get well over 130 degrees some days!)? Does the balsa dry out and get brittle over time?

Thanks for your opinions

Bob Parks

A lot of time is invested building. I love to build but would bee leery about the old balsa. It does dry out over time. Not sure about the 99 to Oly II comparison. The Workbench kits are really nice and faster to build than the originals. Mine will be done soon.

skypup

Oct 19, 2009, 08:13 PM

If the gap is small, it'll just be covered by tape when you're flying. As long as the gap isn't huge, it's just cosmetic.

My wings didn't meet exactly perfectly, but since you're joining them with tape when you fly anyway, a little gap doesn't matter. I use black electrical tape, and since it's opaque, it covers the small gap nicely.

Chuck

My memory is really going south. I don't think I used tape for the gap on my original bird. I never had a problem. I used a lot of rubber bands though. I flew it from a hi start and then put a small OS pet .099 engine in the nose.

smitty14

Oct 27, 2009, 12:59 AM

Thanks for the tips. I hand sanded a 1/16th center rib down to paper thin on the bottom and she looks better now. Balancing on tips of fingers seems to still be heavier on the other wing anyway. I will remember the tape tip - I was wondering, since FS gliders are taped up, makes sense. I will complete the OLY before I start on the Big Bird (which will be for hi-start).
Any preferences on the dowels for rubberband wing hold-downs? I have used nylon bolts on the slopers I have built? Is it just a matter of weight?

cn0rris

Oct 27, 2009, 01:43 AM

It's more a matter of crash-worthiness, I think. A wing attached with rubber bands is less likely to get damaged if you hook a wing on landing. I don't think they add a lot of drag considering thermal ships generally fly a lot slower than slopers.

Also, the Oly II wing structure is designed for a rubber band hold down, in my opinion. It would probably need built-in hard points at the screw holes, and would have a bit different structure in the area of the first few ribs to carry the stress of the screws to the rest of the wing. The rubber bands tend to spread out the hold-down force more than screws do.

Just my $.02, of course. If you try it, I'd like to hear how it turns out.

Chuck

smitty14

Oct 27, 2009, 04:43 PM

Thanks Chuck. Just the kind of input I need. It would require some extra ply blocks - if they are unnecessary then I'll just go without. Got to remember to put those two wire rods in the TE though!

leaktech

Oct 28, 2009, 11:37 PM

Thanks for this thread Chuck, it has helped me a lot the last several weeks. I'm almost finished covering my Oly 2S. I did a few things different and in the interest of maybe helping someone in the future I'll post some items now and more later if I think of anything worthy. I built my ship elec.

Used little epoxy, mostly gorilla glue and elmers. The the whole fuse is built using gorilla glue. Left the plans on the wall and only transfered ribs 1 thru 4 locations to the bottom sheeting. The parts fit like tight spandex so I just let the wingspan end where ever. After the bottom spar is down rib,web, rib, web.....etc. I'm a slow builder, Sky Bench construction technique is new to me so that put me in granny gear. I spent several weeks looking at the plans, reading Bobby's instructions over and over, and this thread also. Hate to admit but my wallet won't allow the premium electronics so went with hobby city parts inside and out. Even the covering is from china. It looks real good right now and the wing is straight like an arrow. I won't be stressing the wing with a winch so no carbon was used on the spar.

Anyway, thanks again Chuck. Great thread.

ps: I'll post an image after I get it on some grass. It's still green here in Phoenix.

cn0rris

Oct 29, 2009, 12:26 AM

leaktech,

It's good to see another Oly IIS coming to life! Glad to hear this thread has been helpful.

I got some experience with polyurethane glues (gorilla glue) after I finished building my Oly, and I would probably use it similarly to how you did. It's pretty fascinating to work with - very strong, yet light too.

As for carbon, I built mine stock too, and have launched it many times off our club winch and have never had a problem. It can take a very stiff launch, and I've had no issues with wing strength.

The only problem I had was launching with old rubber bands into a fair headwind. The rubber bands didn't hold tight enough and allowed the wing to pull away from the wing seat, which caused some fairly spectacular gyrations. I would recommend keeping your rubber bands fresh, and if there's a strong headwind, maybe adding a couple extra.

This plane definitely does not need high-dollar electronics. I used inexpensive full-sized, analog servos, and have never regretted it.

Post pictures when you're done, and I'd like to hear a maiden flight report!

Chuck

Ray Hayes

Oct 29, 2009, 05:23 AM

Chuck and Leateck,

I haven't used Gorilla glue yet, but became a fan of it when I looked at a Challenger fuse built with Gorilla glue. The builder was a pro and I basically could not find any trace of glue at the longeron joints. Very light and very strong fuse.

Question: what glue did you fellas use to laminate the three forward fuse sides.

I use eight rubber bands on my OLY ll S wings and launch hard from a winch with a zoom at the end. The rubber dries out very quickly, especially if left in a vehicle.

Ray
Sky Bench ... Woodys Forever
http://www.skybench.com

cn0rris

Oct 29, 2009, 10:55 AM

Question: what glue did you fellas use to laminate the three forward fuse sides.I used epoxy for mine, as per the build instructions, but next time I'll definitely PU glue a try for this sort of thing. I learned about it building a Fry from Steelhead Products, and really like how strong yet light it is. You can use it a lot of places where you might otherwise use epoxy. It's got maybe 80% of the strength of epoxy, yet has a bit of give in it where epoxy can be brittle. So it makes for a very tough joint.

I've heard of people laminating balsa wing skins to foam cores with it too, and I imagine it works very well for that. It's an incredibly tough joint, and seems to work well with a lot of different materials. With epoxy, once you get a crack or delam going, it'll travel pretty easily. But with PU, since it foams and makes a bunch of micro-bubble-shaped structures, it's a lot harder for a crack to propagate.

I use eight rubber bands on my OLY ll S wings and launch hard from a winch with a zoom at the end. The rubber dries out very quickly, especially if left in a vehicle.I typically use six, with the last two crossed, but put 8 on if I'm launching into the wind. Maybe I'll just make 8 my usual just so I don't have to think about it.

Chuck

leaktech

Oct 29, 2009, 11:30 AM

Chuck and Leateck,

Question: what glue did you fellas use to laminate the three forward fuse sides.

Ray
Sky Bench ... Woodys Forever
http://www.skybench.com

It's the white fast drying gorilla glue. It costs more than epoxy at 5 to 6 bucks per 2oz bottle. Can't find it in larger quantities. It definitely takes practice to learn how much to apply and good spacing of adjacent glue lines. Also don't skimp on lead weights during the cure. Sometimes I do and sometimes I don't use a damp sponge on one surface to speed things up. Laid down a thin 1/16" to 3/32" pattern with 1/2" spacing.:cool:
James

smitty14

Oct 29, 2009, 07:37 PM

Simple ? How do I get a symmetrical LE?

jswain

Oct 29, 2009, 08:13 PM

Simple ? How do I get a symmetrical LE?

After i glue the LE on and am ready to shape, i take a thin marking pen and make 2~4 long, evenly spaced parallel reference pen/ink lines on all three remaining sides - top/front/bottom .

I block plane along these lines so the square leading edge starts to look like one half of a octagon shaped wood pencil does, evenly and symetrically cut along the whole LE length.

The top gets planed the most and the bottom of LE usually gets planed the least.

I **never** touch the center line or most forward LE line mark, on the front side of the LE with the block plane otherwise there is no reference.

Make a thin ply or hard balsa cross-section view template of the LE, side view from plans, so it kind of looks like an animal took a LE shaped bite out of it. Sand (60 or 80 grit)the LE down until the cut out hole of the template sits flush against the front reference line of the LE.

Test this first on scrap wood to get the technique.

It takes awhile but it works.

js

smitty14

Oct 29, 2009, 08:55 PM

I had planned a line at the center. The other two lines will be good reference marks - thanks for the idea. A slider template to check progress will be a good idea too.

mr ray

Nov 02, 2009, 12:42 AM

You did a great job and I can imagine it is harder than it looks. Can you tell me what your oly II weighs auw? Thanks again for a job well done. P.S. I like the harlequin color scheme you used. ..Ray

leaktech

Nov 03, 2009, 04:44 PM

I've installed the spoilers similar to Chuck's method. Was hoping to use the rudder channel for spoiler deployment. They're plugged into the gear channel but I can't figure out how to get full deployment with the rudder stick on a DX7. Maybe it's not possible? And maybe it's not the correct use of rudder stick on a RES Oly2S? After some fiddling it works great with the gear switch. Also I think it would work well if program mix>rate would go to -150%. :) I'm open to suggestions on this setup and not married to anything.

Chuck, if you look close at the vid it's possible to see that my spoiler linkage is similar to yours except that the servos are actuating oppisite from your drawing. I tried without success to do it like the drawing but could not get full up deployment until I turned the servo around the other way.:confused::eek::D
James

http://www.youtube.com/watch?v=XuroQnYBV-w

mr ray

Nov 03, 2009, 05:03 PM

I don't have a spectrum receiver but couldn't you use the flight mode on it and then you would get some different settings for the spoiler instead of full up or down.....Ray

smitty14

Nov 03, 2009, 10:09 PM

Just drew a center LE line and one line each, top/bottom centered on each. Used the planer and sandpaper with the TLAR method. Didn't get around to the LE template, but it looks good so far.
I had to call Hi-Tec for advice on the setup. I may settle for the throttle on the top left flap knob, spoilers on the throttle stick and R/E on the right stick. Xnsmtr is an Eclipse 7, about seven years old.

leaktech

Nov 05, 2009, 12:08 AM

leaktech,

It's good to see another Oly IIS coming to life! Glad to hear this thread has been helpful.

Post pictures when you're done, and I'd like to hear a maiden flight report!

Chuck

Did the maiden today just before sunset. This model turned out very straight best I can tell with these eyes. So I figured it's time to give a little E-power on first throw. (sorry wrong forum:o) The only sailplane previous to this ship is my Parkzone Radian. The Oly2S is far more responsive and seems to float even better on the few local park laps it did from low altitude. It was great to get the maiden behind me and on to fine trimming next time out.

Stuck the tail feathers on with urethane glue....seems fine.:D:cool:
I got a 2100mah batt under the wing all forward as it will go and it's barely making CG.

AUW was a little under 52oz with no hook, big motor, prop, batt, speed c......etc. If anyone knows their Oly2S AUW winch or elec I'd like to hear some numbers. Thanks.

Again this is a great thread and helped me a lot. I think my next woody will be the SB Sky Bird.

James.

mr ray

Nov 05, 2009, 12:41 AM

leaktech

Nov 05, 2009, 01:49 AM

A real nice looking glider. It must be a good feeling to build it and then to find out it flies great also. Let us know how that first high flight goes. I'm jealous that you can still fly in nice weather, it was 4C here today that is about 38F and a real cold wind. Nothing else to do but build. Just building a Gambler AG dlg right now and in January will order a OlyIIS. Maybe one day I'll get down there in the winter instead of freezing my wings off up here....Ray

Yes it's been primo flying weather here most days for 3 weeks. My job is finding leaks on swimming pools..... still going in the water to squirt dye and set plugs.
90F tomorrow, then it cools to 85F the rest of the week. We build in the summer here.

Yes again, it felt very good to see it go up at 1/3 throttle with a little down to stop the stall.

James

ray foley

Nov 05, 2009, 11:59 AM

hi there from Toledo

I have a 32 year old electrocuted Airtronics OlyII, I know it isn't a skybench Oly2s, however, the AUW is 52.6 oz. The OlyII is set up as REM, no spoilers.

the internal equipment is as follows:

Aveox 2526 3y inrunner with Maxxon 4.3:1 planetary gear set
CAM 14x9.5 foldemup prop and spinner
CC phx 45 ESC with a torroid choke in the signal lead
futaba 72mhz pcm dial-a-crash rcvr
two hitec hs475hb analog servos

The OlyII still flies great after all these years!!!

ciao -rjf

TheNightowl

Nov 05, 2009, 03:53 PM

Did the maiden today just before sunset. This model turned out very straight best I can tell with these eyes. James. Purdy birdy, there Leak. Nice job.

leaktech

Nov 05, 2009, 04:01 PM

Thanks Guys, okay I'm right there where Ray is at 52oz's so I'm happy.

cn0rris

Nov 05, 2009, 04:44 PM

James - that's a beautiful bird, and glad to hear it flies well. As for spoilers, I'm sure your method is at least as good - maybe better. Mine don't open quite to 90 degrees, so if you're getting 90, your servo geometry may be better. They work just fine, though.

I still owe my AUW - haven't had time to putter in the garage lately.

Chuck

smitty14

Nov 05, 2009, 07:54 PM

James,
Great looking OLY. Mine is being built electric as well. It is my trainer for what will be my first true sailplane, a Big Bird XL in the box. Was there a reason why you chose the gorrila glue(which color?) instead of epoxy on the tail?
Smitty - the still sanding wings guy

cn0rris

Nov 05, 2009, 08:19 PM

Smitty,

An interesting thing happened to me two weekends ago that turns out to be relevant for the PU vs epoxy question. I was flying my Oly II S in a thermal duration contest, and it was bigger than usual because we were hosting the SCSC competition. On my first landing, I had to land downwind, but I hadn't noticed that fact, and came in much hotter than I was expecting. So I had to put it down hard to avoid going over the safety line and possibly hurting someone.

The entire empennage broke off cleanly, right at the fuse. Otherwise it was completely undamaged.

I don't know for sure of course, but I suspect if I had used PU glue for that joint it would have had enough give to prevent it coming off entirely. Epoxy is fairly brittle, and the sharp shock of the hard landing just shattered it. PU sets up slightly rubbery, and it has lots of small bubbles, so I suspect it would have survived the shock just fine.

So I'm definitely going to use PU a lot more in the future for this sort of joint. The fuse laminations would be another good place where the flexibility would be helpful, and the bulkhead joints as well.

If you're using it for the first time, I would definitely experiment with it on scrap to learn how it behaves. Since it expands during the set, it can force joints apart if you use too much, or if it's not clamped securely. It behaves differently depending on how humid your air is, and how much water you mix in (if any).

Chuck

smitty14

Nov 05, 2009, 08:23 PM

Chuck,
I will have to experiment when I get to that part (I was kind-of saving that for the end). Are you planning the original yellow PU or I have read there is another white gorrila glue?
Smitty

craigrrr

Nov 05, 2009, 08:49 PM

I LOVE MY OLY11s and consider it my favorite sailplane. It makes flat tight turns so it is a great plane for flying with the hawks. My plane is electrified because of my micro flying field.

During a recent electric motor climb-out I let the plane fly too fast and I lost the complete tail in flight. The tail feathers separated completely and the rest of the plane floated down like a leaf to the ground so I got it back (minor wing damage). The combined stabilizer and rudder now reside 70 feet up in a eucalyptus tree. I am hoping the wind will blow it down eventually, but will probably just rebuild the tail feathers.

EDITED 11-13-09: IT IS LIKELY THAT TAIL FAILED BECAUSE OF POSSIBLE DAMAGE BEFORE FLIGHT. I WAS PROBABLY WRONG IN ASSUMING THE FAILURE OCCURED IN FLIGHT DUE TO EXCESS SPEED.
The picture shows the break away area on the fuselage. I think it tore from the fuselage in the weakest area - at the two slots where the two control rods emerge.

So, it might be a good area to reinforce this area (but keep it as light as possible).

cn0rris

Nov 05, 2009, 08:53 PM

Are you planning the original yellow PU or I have read there is another white gorrila glue?The stuff I have is kind of brown looking. I know there is a "white" version, but I have never tried it. Also, when you're done with it, you need to squeeze all the air out or else it'll develop a skin (more of a shell, really) that will prevent you from using the rest of the bottle. In any event, I would buy the smaller size bottle in case you accidentally let it skin over.

Chuck

cn0rris

Nov 05, 2009, 09:00 PM

craigrrr,

Yikes! It looks like yours failed in the wood - not in the joint itself like mine. Is it possible you had some flutter that ripped it loose?

I'll bet a small patch of lightweight fiberglass applied around the exit holes would keep any cracks from forming.

Chuck

cn0rris

Nov 05, 2009, 11:10 PM

leaktech

Nov 06, 2009, 02:14 AM

Great....this thread is rolling again. I'm using the white GG. It's a lot faster than the dark version. On wide areas, lay it down in small ribbons no larger than 1/8" or smaller and keep the spacing about 3/8" to 1/2". Test some scraps first to see what it does. I think it's better to have some small voids than to have it oozing out into a mess. On a critical area like gluing the stab down use too much and monitor it with a paper towel and a skewer to clean things up. If it lifts a part up mush it back down before it sets up and keep the paper/rag and skewer handy. It goes off a lot faster if you wipe one of the parts with a damp sponge first. Also before it's fully set use a sharp blade to remove the ooze or smash it down with a tool. This takes some practice on the timming so you don't make a mess. Use a skewer to test ooze before you cut it off. If you can't weigh or clamp it you'll need to baby sit it while it goes off.

I had a few hours with the Oly and Radian today. The Oly shames the Radian on thermal performance in strong and light lift.:D:cool: I was happy about that because I'm a slow builder and now know the effort was worth it. It seems like the Oly can core a smaller circle too. This is my second sailplane and first ship with spoilers so I was really surprised to learn how well they work.:eek::D As far a looks go the Radian looks very good in the air on my scale, the Oly is just as good in that regard and it's a woody

I'll be turning on some expo cuz it's very responsive on the sticks today. The CG on my fat fingers is just barely behind the spar. I may need some weight up front but I'll try not to do that if possible. A doubler on the hatch/wing former and a hole allowing the battery to move forward might work.

James

mr ray

Nov 06, 2009, 10:40 AM

I was reading somewhere just lately about PU glue. The guy who wrote it says that when he glues things together with it that he tapes the edges. His trick is to put slits or holes in the tape and if and when the glue expands it comes out the holes in the tape. When everything is dry then he just pulls off the tape and voila' a nice clean surface. I have never used Pu but this method sounds like it has some merit. I guess it would work the same for gorilla glue also...Ray;)

leaktech

Nov 06, 2009, 02:05 PM

smitty14

Nov 08, 2009, 08:57 PM

Thanks guys. I really appreciate your responses. I think I will get some white GG and try it for the tail. I am sure I used excess epoxy on the tail, as the basic box of the fuse was what I did first. I needed to see the big picture on weight and now I know better.

jswain

Nov 08, 2009, 10:07 PM

All this talk about tails falling off and not in the same context of a lizard is making me think about adding some 1/64 ply to the rear area of my BigBirdXL
like the following picture from PlanePainters OlyIII build at this web link -

http://www.rcgroups.com/forums/showthread.php?t=1116949&page=12, post#179 - first picture

I already put a band-aid size patch with a control rod cut out to reenforce the area but i think a longer outside 1/64 patch is in order a la post #154.

I hope to see the San diego guys at local SC2 contest in 2010 to see these planes and we can exchange notes about our skybench builds ( live in riverside).

john s.

Ray Hayes

Nov 08, 2009, 10:31 PM

Ok, just measured my All Up Weight at a smidge under 49 ounces, which is right at what Ray Hayes lists as the flying weight on his website (mine's not electric). So I guess I wasn't as heavy as I expected. I did have to add a fair amount of lead in the nose to get the CG right, but I've been taking some out lately as I've been experimenting with a more-aft CG.

I'm finding I like my CG a bit further aft than some pilots - it shows lift better to my eye, and I'm not yet to the point of finding I'm over-controlling it. I think I can remove a bit more before I'm satisfied. I use a fair amount of exponential, though, which probably makes the increased pitch response a bit less touchy.

If I ever build another Oly II S, I'm going to try harder to make the tail lighter, so I can do with a bit less nose weight.

But that said, I've always been very happy with how it flies.

Chuck

Chuck and all ,

Here are my OLY ll S specs and set up posted on the OLY ll S Sky Bench web page:
___________________________________________

Here are the set up specifications on my OLY ll S

Flying weight ... 49 oz
Wing Span ... 102.5 "
Wing Area ... 908 sq in
Wing Loading ... 7.77 oz per sq ft
Balance Point ... 6 - 3/16" Forward of T. E.
( Wing's trailing edge )
___________________________________________

The most important spec is the wing loading.

All over the RC Groups I see guys posting weights of various sailplane designs without stating what the weight means in terms of wing loading.

Also, guys talk about making a sailplane lighter, without mentioning what servos and batteris are installed in the plane.

It all starts with wing loading and balance point. The key is knowing what wing loading works best for a given design. A good example is the already built AVA, many of the guys flying AVA's in contest have more or less added permanent ballast. Because, 90% of the flying weather conditions have proven the AVA to be too light. I'll also add that many sailplanes are flown too slowly. They all go up in lift and all come down in sink, so the plane that can fly fast enough to fly out of the sink will live to find a thermal.

An OLY ll S flying at 7.77 oz per sq foot of wing area (wing loading ) will go up in gopher ....

But, will fly fast enough to have a good chance to fly out of sink.

And the OLY ll S can amazingly, turn inside that gopher ....

So if nose weight is required to balance at the proper point on any sailplane, a larger battery could be the best answer if teh wing loading is satisfactory.

Hope this helps

Ray
Sky Bench ...Woodys Forever
http://www.skybench.com

cn0rris

Nov 09, 2009, 12:02 AM

John,

Don't worry about the strength of your Oly. If you build it as planned, you'll be just fine. I really nosed mine into the ground hard - something was going to give. And the repair was simple and strong.

And Ray's right about weight. The Oly can take it just fine. Mine came out at 49 oz built completely stock, so his specs are right on.

Chuck

leaktech

Nov 09, 2009, 09:52 PM

Chuck and all ,
___________________________________________

Here are the set up specifications on my OLY ll S

Flying weight ... 49 oz
Wing Span ... 102.5 "
Wing Area ... 908 sq in
Wing Loading ... 7.77 oz per sq ft
Balance Point ... 6 - 3/16" Forward of T. E.
( Wing's trailing edge )
___________________________________________

The most important spec is the wing loading.

An OLY ll S flying at 7.77 oz per sq foot of wing area (wing loading ) will go up in gopher ....

But, will fly fast enough to have a good chance to fly out of sink.

Ray
Sky Bench ...Woodys Forever
http://www.skybench.com

I'm pretty happy with the way my E-Oly is thermaling. The wing loading is only .4oz over Rays pure glider Oly. I've got a pretty big outrunner in it and a 2100mah lipo under the wing. It will go strait up, even more so than my Radian and it thermals better too. If anyone is on the fence about building one don't hesitate it's a great and a good looking sailplane.

James

Ray Hayes

Nov 13, 2009, 05:34 AM

Don't lose your tail feathers

--------------------------------------------------------------------------------

I LOVE MY OLY11s and consider it my favorite sailplane. It makes flat tight turns so it is a great plane for flying with the hawks. My plane is electrified because of my micro flying field.

During a recent electric motor climb-out I let the plane fly too fast and I lost the complete tail in flight.

__________________________________________________ _________

Sure glad your OLY ll S had minimal damage, but I have to tell you, your conclusion about the tail feathers being torn off due to speed can't be true. Statements like yours can be detrimental to Sky Bench's reputation of providing quality and strong design woody kits.

And also confuse the many beginners using RC Groups as a source of information on building and flying woody r/c sailplanes.

This same stab/mount constuction is used in all my Bird Series, all the OLY ll series and so many other mfg's kits over the years.

I have, for years and years, dove vertically from speck out heights in front of hundreds of contest witness ( I'm not the only one do do this ) with my various Sky Bench designs and have not had the tail feathers fly off. I have flown F3B speed runs without the tail group flying off. For years and years, contest landings on the point tape have resembled a vertical crash and the tail groups don't break off.

The answer to what happened to your sailplane is the rear fuse area was damaged previously in hard landings or other mishaps. The type of landing where the sailplane rear fuse area is subjected to side forces caused by the plane rotating on landing and the rear of the fuse strickes a clump or ridge with the fuse side or one side of the stab. The latter being my vote on what happened to cause the fuse to break.

The extra long 1/8" plywood laser cut stab mount goes well forward in the fuse, way forward of the leading edge of the stab, does not break due to speed in any direction.

I have used 30 minute epoxy to glue the stab to the stab mount for years and years without ever losing a stab to glue failure.

It is a good practice to check your plane over, front to rear, hinges and controls before each flight.

Hope this helps.

Ray
Sky Bench ... Woodys Forever
http://www.skybench.com

TheNightowl

Nov 13, 2009, 05:50 AM

So if nose weight is required to balance at the proper point on any sailplane, a larger battery could be the best answer if the wing loading is satisfactory.

Hope this helps

Ray
Sky Bench ...Woodys Forever
http://www.skybench.com
I just want to second what Ray says here. If you have to add weight to a plane, make it useful weight over dead weight if any way possible.
Nightowl

Ray Hayes

Nov 13, 2009, 06:03 AM

I have narrowed the fuse on one of my 2M Lil'Birds, limiting battery width considerably. The battery I installed is an in-line 5 cell Nimh, located right up against the nose block.

Holds a charge forever.

Ray
Sky Bench ... Woodys Forever
http://www.skybench.com

cn0rris

Nov 13, 2009, 12:54 PM

Just a word of support and respect for Ray and SkyBench here. He's right about the robustness of the structure - the only failures I have ever experienced with my Oly II S have been because of hard landings. I have never had an in-flight failure, and I have many hours on it and have learned a tremendous amount. The SkyBench Oly II S is an extremely sturdy design that has served me well as I've learned a lot of new skills and made the usual piloting mistakes along the way.

I used my Oly while learning how to winch launch, and it's proven itself to handle hard launches with a stock (no added reinforcements) airframe. I've learned how to fly in TD contests, and how to do precision landings. Sometimes, I've landed pretty hard while learning the art of the TD contest, trying to get the best possible landing points. In all cases, the Oly has surprised me by how strong it is. I've done things that should by all rights have broken something, and it's survived with only cosmetic scratches.

The damage I described that started this recent discussion was a result of an extremely hard nose-in landing when I botched a downwind landing in a contest, came in hot, and had to put it down hard to keep it from leaving the landing safety zone and plowing into a crowd of people. It's the fact that I only broke my empennage that is remarkable, and it's a testament to how strong the Oly II S structure is.

Anyone looking for a thermal plane that flies great and can take a lot of abuse would have a hard time finding something better.

Chuck

craigrrr

Nov 13, 2009, 01:09 PM