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I Knew It! – Where RC Airplanes are Leading Me

Posted by Tom Benedict on 13/02/2013

I’m starting to see a pattern…

When I was a kid, I loved kites. The idea that something that had no power source of its own could fly was fascinating. It was even more fascinating to tie payloads to my kite string and lift them as well. (Those little green baskets that strawberries used to come in were awesome for making gondolas!) I should have known it was a sign of things to come.

Years later I got into sailing. I’d been on power boats, but they just didn’t do it for me. Again, I think the fascination had to come from the idea of being in a vessel that had no inherent power source, but that still moved through the water with ease. No surprise, my wife and I gravitated toward catamarans – some of the most efficient sailing vessels ever made.

When I got into aerial photography, I guess it was only natural that I returned to kites, albeit seriously upgraded from the ones I used as a kid. Using kites for aerial photography offers serious operational benefits, such as the ability to sit in one location for hours, if necessary, until the light happens. But it has non-photographic benefits as well that go back to why I got into kites and sailing in the first place: the silence, the power, the peace.

And now I’m getting into RC airplanes. For a variety of reasons the plane I chose has a large high-aspect wing, low wing loading, and a decent glide slope. These are all features you want when sticking camera gear on an airplane. But they benefit something else as well: using the plane as a glider. And the more I fly it, the less inclined I am to use it for aerial photography. It’s just too fun to fly! And the more I fly it, the more I find myself cutting the motor entirely and gliding. Just like flying a kite, flying a glider is therapeutic.

The problem has been finding places and times when I can fly. The wind around my house ranges from moderate to torrential. But it’s almost never zero. When I got my plane I thought that kites and airplanes would fill two different parts of the wind regime: zero wind = airplanes, moderate wind = kites. Too much wind means the plane stays home. And there’s almost always too much wind. I thought I was stuck. But all that changed when I discovered slope soaring.

When wind encounters a slope, hill, cliff, or even a generously sized building, the wind has to go up and over the obstruction. This creates an upward moving body of air just in front of and above the slope. Put an airplane in that body of air, and it flies. And since energy is being pumped in in the form of upward moving wind, the airplane can theoretically fly indefinitely, just like a kite. This works so well, the airplane doesn’t really need a motor at all. All it needs is enough oomph to be able to use the lift from the wind and turn it into speed.

There are, of course, idealized regimes of airplane design that lend themselves to slope soaring better than others, just as there are idealized regimes of automotive design that lend themselves to racing on flat pavement better than others. But any car will roll if you position it at the top of a hill and release the brake. Likewise, practically any RC airplane can be used for slope soaring. It may just require a slightly different setup than what you’d normally use for open field flight.

It turns out the Bixler 2, my first and so far only RC airplane, makes a darned good slope soarer. I discovered this when I couldn’t find a good place to fly. I finally wound up at the cliffs above Hapuna Beach where a moderate on-shore wind was blowing. The cliffs make a decent slope, and the almost completely laminar on-shore wind make for wonderful flying conditions. I wound up flying for more than half an hour, and only had to use my motor a couple of times to correct my rookie mistakes. When I put the battery on the charger afterward, I was amazed to see it top off with only 330mAh of charge. It’s a 2200mAh battery. I could’ve gone for hours.

When I got my plane, I felt a little dirty – like I’d stuck a motor on a sailboat or put a propeller on a kite. I should’ve known it wouldn’t work out like that. Instead, I found a way to make the airplane fit right along with everything else. It doesn’t matter if it’s kites, boats, or airplanes. It’s all about the wind. It’s always about the wind.

– Tom

Posted in Kite, RC Airplanes, Sailing | Leave a Comment »

Ready for a Weekend!

Posted by Tom Benedict on 08/09/2012

For a short work week, it’s been a long week at work. But it’s been a good one! Most of the external parts for the cameras are done. If fortune continues to shine on us, it’s looking like we might send out all the external parts for anodizing some time in the next few weeks. We still haven’t settled on a color for these things, but it’s looking like the original orange I used for making the CAD renderings may win out in the end. The only requirement is that the cameras be brightly colored. One of them will be located almost knee-height when it’s on the telescope, in an area where forklifts are in use. If I could make it fluorescent orange with tiger stripes, I would! But I’d settle for fire engine red or hot pink, too.

This is, I hope, the last rendering I post of this camera design. The next picture I post should be the real deal:

Sitelle Camera September, 2012

I’ve still got some internal parts in the queue, though, so the work is far from done. I’m working on the vacuum feed-throughs next week, and hope to make a start on the cold finger/foot/strap assemblies as well. That is a story all its own:

Any time you build a cryogenically cooled camera, you need some way to isolate the cold bits so they don’t let heat from the room-temperature camera body leak in. Along with this, you need some way to attach your cold source to the cold bits so any heat they generate or collect through ambient radiation can be taken away. The first is accomplished by using some thermally insulating material to support the cold bits. In these cameras I’m using G-10 fiberglass tabs to separate the warm parts and the cold parts. The second is accomplished by using some thermally conductive material to draw the heat off. In these cameras that’s done through an unfortunately complicated assembly of copper and aluminum.

Usually these assemblies are comprised of three parts: the cold head (the cold source), the cold strap (the bit that connects the cold head to the rest of the assembly), and the cold foot (the bit that actually connects the cold to the back of the detector chip). In this case our cold head is a Polycold PCC cold head. Our cold strap is a piece of copper 0.20mm thick x 12mm wide x 90mm long. Our cold foot is a block of copper about 35mm square and about 15mm thick.

The trick is that you have to be able to remove the cold head to access the rest of the camera. So somewhere in there you need some sort of a removable joint. In one camera I’ve worked on, this was done using a spring and two pressure plates. One of the plates is connected to the cold head. The other is connected to the cold strap. Push the two together, and the force of the spring keeps things in good solid contact. Voila! The cold head / cold strap / cold foot circuit is complete!

The original design for this camera also used a spring, but concerns about mechanical vibration coupling between the cold head (which does vibrate) to the detector chip through the spring ruled that out. I had to come up with something else. Over the course of the last three months I tried all sorts of ideas, none of which panned out. The best approach I had used a single bolt to bolt the copper cold strap directly to the cold head. Only problem? There was no way to reach the bolt with a wrench! No matter what I did, there was no way to get a tool in there. Time and again, I found myself back at the drawing board, starting over from scratch.

Then one of my co-workers came up with a brilliant idea: Why not use magnets? Stick a magnet on the cold head and a magnet on the cold strap, and let the magnets do the work of holding the two in contact. The idea is similar to how the clasp on a lot of handbags work these days. We tried it on the bench in the lab, and it worked great. So yesterday I mocked up a set of hardware to try this in a real cryostat. Today I installed everything and started pumping it down.

Installing the cryo head was dead nuts simple. As soon as the two magnets got close enough, “Clack!” they came into contact. The magnets are self-centering, so some of the off-center contact problems we had on the spring designs are also solved. Even before getting things cold, I could already tell the idea was working. In order to drive some of the water off the cryostat walls, I stuck a heater on it while it was pumping down. Both the cold head and the cold foot registered the heat being applied. Under vacuum, the only path that would let both parts see the same heat is the cold strap. Only way for that to work? For that joint to be solid. Yaaaay!

I plan to start cooling Saturday morning and see how it cools through the weekend. By Monday we should have good numbers for how it’s likely to behave. If it all works out well, I’ll start cutting parts for the real cameras on Tuesday.

But enough work! It’s time for a weekend!

And speaking of weekends, I finally ordered the tools and parts to replace the main halyard on our boat. My plan now is to finish drawing up the new main halyard winch in CAD, put the old winch back into the mast, and get the boat ready for when the halyard bits all show up. We should be sailing by next weekend. Meanwhile I can start machining the new winch, which is being designed not to let the cable jam ever again. When it’s ready, swapping them out will be about an hour’s work: the perfect project for a weekday evening with the promise of a weekend sail at the end of it.

Time to play.

– Tom

Posted in Astronomy, Engineering, Sailing | Leave a Comment »

Amsterdam Photos a Work in Progess, and Sailing Woes

Posted by Tom Benedict on 26/07/2012

The SPIE conference in Amsterdam was fantastic. I came away with a ton of new ideas for stuff to try at work, had a great talk with an old friend I hadn’t seen in ages, and basically got jazzed up again to be working at a telescope. Everything a conference should be. Even better, my father was there. My days were spent at the conference while he took in the sights of Amsterdam and the surrounding country, and our mornings and evenings were spent catching up. It couldn’t have been better.

Though actually, it was! In addition to the SPIE conference and spending a week with my father in The Netherlands, we also went out to do KAP with Ramon Pallarés at the windmills near Zaandijk. Ramon and I had traded emails and forum posts for years, but this was the first time we’d actually met each other face-to-face. Strange as this may sound, it’s pretty typical for people doing something as uncommon as KAP. There are far too few of us, scattered over far too much of the earth’s surface, with far too little money to travel. Meeting another KAPer face-to-face is rare. So we made the time count.

Unfortunately I don’t have any photos from Amsterdam ready to share. As soon as I got back, work sucked me right back in. I’m back in manufacturing mode on the cameras for our new instrument, we’re back in R&D mode on the continuing vacuum woes on our existing instruments, and we’re getting ready to coat another telescope’s mirror. Basically, life went back to normal before I had a chance to work on all the photos to my satisfaction.

So what did I do the first chance I got? Go sailing, of course!

Setup is getting faster. It’s almost like we finally have a clue what we’re doing. We took off from Kawaihae again, but only as far as the reef outside the harbor. As soon as we were at the outer edge of the reef we furled the jib, pointed nose to wind, and jumped in. The reef out there is fantastic. The water isn’t cloudy the way it is near the sandy beaches, and the coral is outstanding. I had to stay with the boat most of the time, so I didn’t see as much as I would’ve liked. But it worked out really really well. I can’t wait to go back.

Unfortunately I’ll have to wait. Seeing the reef was the last good thing that happened that day. After that, it just went downhill.

Rydra and the kids had a hard time getting back on the boat. This had been an issue with our earlier MOB drills, but we managed it. This time everyone was tired from swimming around the reef, so it was much worse. Eventually everyone was back on, but Rydra was bruised and battered by the time she was out of the water. This is an issue we have to solve before we go boat diving again.

To make matters worse, the chop had picked up and Rydra became motion sick. So far her track record for motion sickness is 100%: three trips out of three. I told her I’d work on the problem of how to get people on and off the boat if she looked into solutions for motion sickness. And before anyone gets the idea this is something you just press on through, get an iron gut, man up, whatever else, forget it. This is a pleasure boat. If someone is writhing around on deck in abject misery, they’re not experiencing much in the way of pleasure. The whole point of restoring the sailboat was to have fun. I won’t go out again if she’s not able to enjoy it, too. Rydra loves sailing, so there’s plenty of motivation on her part.

Tacking into the harbor was incredibly smooth. (Ok, I lied. One more thing went well that day.) This is a far cry from our first time out, when we nearly hit the harbor wall. This time my son was on jib and I was on tiller. We came into the harbor, turned into the wind, and I jumped in to stop the boat. My son popped the jib sheet, and hauled on the furling line like a real deck ape. Seconds after making our turn, the jib was secured and we were ready to drop the main.

When I tried to lower the main, it jammed. The main halyard on the P-Cat is a steel cable that runs up and over a masthead sheave, down the sail track on the mast, and into this cute little winch that’s built into the mast. Except it’s not all that cute when the cable hops off the winch drum and wedges itself between the drum and the side of the mast. No amount of wiggling, winding on, winding off, yanking, or anything else cleared it. It was stuck fast.

Finally, with that sick feeling of dread in my gut, I sent my son to get the Leatherman out of my car so I could cut the cable. This wasn’t a small decision. Replacing the main halyard would be expensive. Because of how the P-Cat is set up, it’s not a straightforward procedure, either. Deciding to cut that halyard was going to keep us land bound for some time. All these thoughts went through my head when I told him to go get my Leatherman.

He came back with the spare parts box instead. I couldn’t believe it. I admit, I yelled. Then I sent Rydra to get it. After what felt like an eternity she came back empty handed and asked where it was. (I’d told her it was in the glove compartment!) Finally I sent both of them back with a very clear idea of where to find it. I’m pretty sure they were both ready to kill me at that point because of how explicit I was when I made very clear where they could shove it if they didn’t come back with the damn thing!

In my defense, though, my shirt was up on deck where I couldn’t reach it, I was burning in the sun, my aqua socks were on deck with my shirt, and my feet were bleeding from trying to hold a five hundred pound boat steady while standing on sharp lava rock. I had reason to be bitchy, even if I didn’t have the right. They came back with the Leatherman, though,  (thank goodness!) and held the boat while I chopped our main halyard in half. Crap.

With the mainsail safely down, the only thing left to do was to get the boat on the trailer, take down the mast, and wash the salt water off of everything. But as we drove the boat away from the ramp, we found the entire marina had been turned into a giant parking lot. Cars and trailers had been parked everywhere, blocking all the wash stations and making it impossible to clean the boat. One of the most basic rules of public boat ramp etiquette, utterly ignored. We realized we’d never get the boat clean at the marina, so we finally just pulled over wherever we could, tore everything off the boat, and threw it in my car.

Unfortunately I took the “throwing” part a little too seriously and wound up throwing a plastic coat hanger the length of my car, straight into my windshield. I didn’t find out until later, when I was driving our saltwater covered boat back up Kohala Mountain to our house, that I’d managed to break my windshield. Yeah. With a plastic coat hanger. >sigh<

Yep, I managed to vandalize my own car. Some days you feel more stupid than others.

Ok, I’m completely full of crap. Because the rest of the day went swimmingly well with only one exception. When we got home everyone pitched in to unload. Rydra set up the hose and rinsed off everything that had touched saltwater, the kids hung up all the PFDs and got the car unloaded, and I stuffed all the running rigging into mesh bags so we could wash it. Once the car was empty my older daughter started making lunch while Rydra and I washed off the boat. By the time we came inside, the calm after the storm had settled on the house.

But for that one exception…

As we were setting the table for dinner, I noticed my son’s eyes were puffy. We were all a little sunburned on the cheeks, but this went beyond mere sunburn. So I asked him what was up. He just stared at me. Then his mouth started to quiver. Oh crap. “Let’s take this in your room where we have some privacy.”

Here’s a lesson to all the parents out there. And here’s confirmation for everyone who had rough spots in their childhood because of one of their parents: A parent’s actions have consequences. Sometimes these go well beyond what’s apparent at the time. I remember things from my childhood that didn’t even register on my parents’ radar. Until a parent learns to put themselves in their child’s position, they’ll never see the impact their actions can have on their kids.

My son told me that he felt responsible for everything that had happened at the harbor. All of the yelling, the swearing, the throwing, even the broken windshield. Why? Because when I’d asked him to get me my Leatherman, he’d come back with the spare parts box instead and I’d yelled at him about it. Gone was all the pleasure of taking a crew position on the boat. Gone was the attaboy he got for doing such a good job of manning the jib when we tacked into the harbor. Gone was the satisfaction of doing such a snappy job of furling the jib and securing it. At the end of the day he felt terrible.

And I felt like a monster. I didn’t even try to explain how rough the day had been, and that I’d just snapped. Go down that path, and you can justify anything. The bottom line was I was a jerk, and took it out on the people around me. And I’d robbed him of everything he’d done right that day. So I did the only thing I could do. I got down on my knees and offered him the most sincere apology I could. He accepted it a helluvalot faster than I deserved. Then I went through the day as I saw it, pointing out how well he’d done on the jib, tacking into harbor, furling the sail, and reminded him that in the end he was the one who brought me the tool I needed. He done good. By the end the smile was back. Not strong, but at least it was there.

We can’t sail right now. I still haven’t managed to take apart the winch, and without a main halyard there’s no way to raise the mainsail. But I’m motivated to get Smilodon back out on the water. My son has a date with a jibsheet, and Rydra has a date with the tiller. As for me? I kicked my date overboard. Captain Bligh doesn’t get to sail with us any more, even if it kills me.

Smilodon - July 2012

Here’s to happier voyages to come.

– Tom

Posted in Sailing | Leave a Comment »

My Favorite New Tool: West Marine Epoxy

Posted by Tom Benedict on 21/06/2012

When I started work on Smilodon, I knew I’d have to get a bunch of rigging, blocks, shackles, etc. After seeing the state of the hulls, I also knew I’d need to get epoxy, polyester, and gel-coat resins. I planned to use the epoxy as my mainstay fix-it resin, polyester as the primer layer prior to applying gel-coat, and gel-coat for the final surface coat. Rather than mess around, I splurged and picked up West Systems resin, hardener, and filler. It was expensive, and it irked me I had to buy pumps separately. But it’s proven stuff, so bought it anyway.

I wound up having to repair all manner of holes, dings, old screw holes, scratches, etc. By the time I was done I’d mixed dozens of cups of epoxy, run it neat, at ketchup consistency, at mayonnaise consistency, and I wound up mixing up one particularly stiff batch that was closer to putty. By the end, it had become my favorite new tool.

Last night I finished the work on the battens for the mainsail. For some reason the battens had been bolted into the main under far more tension than I like to run. I cut the bolts off, pulled the battens out, stuck Hobie batten tension caps on the luff end, and Tren-Tec leech caps on the leech end. Before inserting them into the sail, though. the Tren-Tec caps had to be glued on. They suggested using epoxy or silicone. Without any hesitation I went for the epoxy.

The session went something like this: Lay the battens on the table, pull the caps, wipe battens with alcohol, shoot alcohol into the caps. Dry thoroughly. Mix a cup of epoxy (one squirt off each pump – perfect ratio every time!) Wet the batten tips with neat epoxy. Mix in some colloidal silica filler to a consistency between ketchup and mayo, and load it into a syringe. Shoot the caps full of epoxy and squooge them onto the tips of the battens. Wipe excess, line up, and set aside to set.

This took me all of fifteen or twenty minutes, tops. When I checked the caps this morning, the epoxy was hard as a rock. Still, I’m giving it the full 24 hours to cure. Now my leech caps are a permanent part of the battens. Done.

Over the years I’ve used a variety of epoxies I bought from the hardware stores. Tubes go bad, resin gets compromised, and mixing ratios are always approximate. Never again! I’ve got all my West Systems stuff on one shelf in my cabinet, so using it is no more difficult than pulling a screwdriver out of a drawer.

Love it.


Posted in Engineering, Sailing | Leave a Comment »

Man Overboard!

Posted by Tom Benedict on 19/06/2012

Work has been utter hell. Twelve-plus hour days are getting to be common, and six and seven day work weeks are becoming the new norm. We’re all ready for things to get back to normal. And we’re all making the most of the time off we do get. I missed a holiday last Monday, and I was at the summit from 7am to about 9pm Saturday. Sunday was my one day off. So I made the most of it.


We took Smilodon, our rebuilt Pacific Catamaran, out for the morning. Winds were light, but enough to make for good sailing. Because of work I haven’t had a chance to do any work on the mainsail battens, but otherwise the boat is really starting to shape up. I wanted to see how far we could go in a reasonable amount of time, but back in the back of my mind what I really wanted to do was some man-overboard (MOB) drills.

I believe in MOB drills the same way I believe every new driver should skid their car, just to know what it feels like. Think of it this way: If you spend a couple of hours skidding your car intentionally and learning how not to panic and how to get your car back under control, when it happens on the road your chances of survival are considerably higher. The same is true of MOB drills: If the first time you do a MOB drill is when someone actually falls off the boat, your chances of knowing what to do are slim. But if you practice it regularly, it’s almost a non-event.

There’s another benefit to MOB drills: If the people you sail with know with certainty that you can turn around and pick them up in under two minutes, they’re a lot less likely to panic if they wind up going overboard.

Besides, MOB drills are fun!

I wasn’t quite sure we were all ready for MOB drills, but I at least wanted to try with an inanimate object. So I brought along an empty milk jug. Fill it halfway with water, and it makes a pretty good simulated MOB. But before I could even think about pulling it out, my son pointed to starboard and said, “Is that trash?” I looked where he was pointing, and saw a bait bucket floating on the water. MOB DRILL!

I had to tack twice to reach the bait bucket, but we got it on the first pass. Once everyone saw how smoothly that went, it was like a dam breaking. First Rydra and our son went over the side. Rydra grabbed a camera, and took pictures as we sped off into the distance:


And as we came back around to “rescue” them:


After my daughters and I came around and “saved” them, they went in the drink for their own turn at sea.  By the end of the day we’d run two live MOB drills, and one more dry run when Rydra’s hat fell off. I only missed my first approach once, when my two daughters were in the water. I made my turn too soon, and didn’t have the sea room to finish the tack and come back for them. But the second pass went like clockwork.

The P-Cat is significantly heavier than the Prindle 16 Rydra and I used to sail. The P-16 could literally turn on a dime, but the P-Cat needs a little more room. It also has a lot more momentum because of the added weight, so it won’t stop as quickly as the P-16. Still, once I got the hang of it, I found it to be just as maneuverable

We sailed as far south as Puako. By the time we turned back, the wind had dropped to a gentle breeze. We were cutting across the swell, which made for a slow roller-coaster of a ride. But the water was smooth and the reefs, only thirty feet below us, were gorgeous. I had to skipper the boat, but the kids knew just how to enjoy the view.


The experience of the MOB drills helped when it came time to sail back into the harbor. I didn’t mess around with dropping the main early and sailing back under jib alone. We came in under full sail, made our turn into the wind, and Rydra and the girls jumped into the water while my son and I furled the jib and dropped the main. Less than a minute after we’d cleared the harbor wall, we were nose to wind with no sail set. Perfect!

There’s still one big step left before I’m 100% confident in boat and crew: I need to fall overboard, and they have to come back and get me. Until that happens, I’m leery about doing anything that puts me in a position where I might go in.

To date I have only unintentionally gone overboard on a boat twice. The first time was when I was struck by the boom during an unintentional jibe on our P-16. The second was when I was hiked out on a wire, and my trapeze line failed. Dodging the boom became second nature after a while, and the boom on the P-Cat is more than a foot higher than the Prindle 16. But equipment failure can and does happen. That trapeze wire worries me. At the moment I’m the only one with a trapeze harness. But until my crew can come around and rescue me from the water, I have no business hiking out on a wire. If the wire breaks or a knot fails, I’m in the water with no assurance anyone will come back to get me.

So, of course, this is top of the list for the next time we head out. Someone else will skipper the boat, and I get to be the man overboard. It also means I get to play around with cameras! So next time I hope to come back with more pictures of our P-Cat, the beautiful waters of Hawaii, and anything else we encounter along the way.

– Tom

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On The Water and In The Air

Posted by Tom Benedict on 12/06/2012

Two big landmark events happened last weekend: we got the boat out on the water, and I had my turn with the World-Wide KAP Banner.

Sailing was… Well… You know that song, “Feels Like The First Time” by Foreigner? Yeah, it felt like the first time. Felt like the very first time. In case anyone thinks this means it was wonderful, passionate, and opened new vistas to us, you missed the point: It was awkward, bumbling, kinda messy, full of mistakes, but we all came away smiling.

In a place where the wind never truly dies, you can only go so far rigging a boat in the yard. A bunch of little stuff still needed to be done when we rigged the boat at the harbor. It took us two hours and involved more than a few mistakes. But finally we were ready to put in. I’d forgotten how easy it is to control the power on a cat, so we tried sailing out of the harbor with only the jib. We also completely forgot to put the daggerboards down. The result? We almost side-slipped into the harbor wall! Eventually we sorted it out.

Once the main was up and the boards were down, we found the boat pointed well. We were able to point 45 degrees to the wind and still make good headway. The helm balance was almost perfect, with just a slight bit of weather helm. The jib furler worked perfectly, and the main halyard winch worked well enough for the purpose. Our tacks were anything but picture-perfect, but eventually we made it out of the harbor and sailed as far south as the Mauna Kea Resort. Rydra asked that we turn around at that point, so we tacked back and headed home.

We weren’t done with the mistakes, unfortunately. Despite blowing every tack and having overwhelming evidence that we could bring the boat to a standstill at will, I was concerned about sailing into the harbor under full sail. So we lowered the main and tried to sail in with just the jib. This time we missed the harbor completely and almost hit the harbor wall. I had to jump overboard and swim/tow the boat away from a bunch of fishermen who were more than surprised to see our ineptitude. (At least they got a good laugh out of it!)

Eventually I put the main back up and we sailed in as the last of the wind died. We hosed everything down, packed everything up, and headed home alive, mostly injury-free, and smiling. Oh! And alive! Did I mention that? That’s a good thing.

We’ve got some tweaks we’re going to make before taking it out again. The battens on the main are an over-tensioned mess, I want to add stirrup ropes for climbing into the boat, and we need to come up with a better way to stow our lunch so it doesn’t get soaked. But these are minor tweaks. We’re good to go for next weekend.

And no, I took not one picture. Not. One. We were so busy sailing, the camera never came out of its case. Ah well. Next time.

The other big event was the World-Wide KAP Banner. There’s a story to this one:

Some years ago, a fellow KAPer named Ramiro Priegue came up with the neat idea of making a banner and sending it around the world to anyone who does KAP. As each KAPer received the banner, they were to sign it, take it out, photograph it from the air using a kite-lofted camera, and then pack it up and ship it to the next person on the list. His idea was warmly received, and shortly afterward the World-Wide KAP Project was born. The banner was made, and the first photograph was taken. Since then it has traveled all over the place. The banner is covered with signatures from KAPers from the far corners of the globe. It’s a piece of kiting and KAP history.

But where to photograph it? I thought about all the places I’ve flown on the island, and finally decided to take it to Anaehoomalu Bay. This is where I took my first really photogenic picture from a kite. It’s where I went when I switched from my first KAP camera, a Nikon Coolpix, to my second, a Canon Powershot. It’s where I got my kite stuck in a tree for the first time. It’s where I crashed my first rig. In a way it’s a part of my own KAP history. Plus, it’s gorgeous there.

I walked out to a spot where an old marine diesel had washed ashore ages ago. The engine is rusty to the point of being mummified. The thing is so old, it shows up in maps of the area. It’s one of my favorite KAP subjects. I pulled the banner from its bag and laid it out in the sand next to the engine. It was great seeing all the signatures everyone had put on the banner. There was artwork, logos, cartoons, names, stories, all kinds of things. I wanted to stop and look at them all, but I only had a short time to photograph the banner. I found myself wishing I could take a picture so I could read them all at my leisure. Then I had to laugh: That’s exactly what I was doing!

So without further ado, the banner for the World-Wide KAP Project at Anaehoomalu Bay, on the Big Island of Hawaii:

WWKB and Diesel

WWKB Hawaii

Posing with WWKB

WWKB Anaehoomalu Bay Vertical Panorama

Clear skies and fair winds.

– Tom

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Kudos to Sailcare!

Posted by Tom Benedict on 06/06/2012

Our jib came back from Sailcare today. OH MAN!

Several times already in the restoration of Smilodon, Sailcare came to the rescue. The pecuilar combination of sheave and cam cleat that’s used on the jib sheets of the P-Cat? Sailcare had them when no one else did. Affordable fully adjustable trapeze sets? Sailcare again. And now our sail…

I knew Sailcare did more than just stitching. They do a very comprehensive sail cleaning procedure called the LeMauney process. Sure. Whatever. I just needed the holes patched and the zipper sewed on properly. But why not get it cleaned while it’s there? Can’t hurt, can it?


Our jib came back looking practically new. Ok, ok, when I laid it on the floor and looked at the color of the cloth I could see it was still somewhat yellowed. But it was nothing nearly as bad as it had been. The stains? Gone. The dirt? Gone. The mouse droppings (I kid you not… I had some surprises when I pulled the old zipper off!) Gone. The corrosion build-up on the grommets at tack and clew? Gone! And the cloth itself feels fantastic. (The LeMauney process re-impregnates the cloth with resin.) This sail is at least twenty years old. There’s a good chance it’s older than I am. Now it doesn’t even look like it’s been used on the water.

I almost felt bad re-attaching the jib blocks. The line between the jib’s clew and the blocks isn’t the cleanest in the world. And now it shows! I may take them back off and wash that line before putting it back on.

I unpacked and re-packed our gear bag to be certain I had everything in it and we were good to go for the weekend. We’re ready for the water. The kids are starting the summer as landlubbers. By summer’s end they’ll be sailors!

When we do finally tear things down to re-do the decks, I’m planning to pull the battens out of our main and send it off to Sailcare to get the same treatment our jib got. It’s a little softer than the jib, so I don’t know what they’ll be able to do for it. But I’m looking forward to finding out.

– Tom


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Sailing Soon and SPIE Posters

Posted by Tom Benedict on 01/06/2012

Good news! Sailcare sent word that our jib is in the mail. Now the only question is when it’ll show up. I’m guessing at some time next week, so next weekend we should be on the water. Today I went through the list of things left to do on the boat and started hammering out the last of the little things. County-issued VIN sticker on our trailer? check! Public boat ramp fee stickers? Check! Verified daggerboards can be inserted the full length of the trunk? Er… not checked… But by the end of the weekend, the only thing left should be to put new telltales on the jib.

Meanwhile I’m getting ready for the SPIE Astronomical Instrumentation 2012 conference, which starts in Amsterdam a month from Monday. Manuscripts are due by the 6th, and mine is almost done. I got the last of the figures in this afternoon and sent it out for edits. The only other task left after the paper is to put the poster together. Technically I can finish the poster the day of my poster session, so long as I get it printed in time. That seems needlessly risky to me, though. I’m planning to print it before I leave and take it with me on the plane.

I like making posters. I don’t mind public speaking, even though I get terrible stage fright. But putting together a talk isn’t nearly as fun, to me, as putting together a poster. I don’t really like the traditional academic or engineering poster formats, so I take posters as a chance to have fun with graphic design. I look at it this way: The whole point of a poster at a poster session is to grab the eye, make it easy for a bystander to get the gist of what you’re saying, and give them enough information to ask you at least one decent question. You don’t need to reproduce the entire contents of your paper on your poster! In short what you need is eye candy.

This is my poster from SPIE 2010:

SPIE 2010 - Espadons PCC Poster

Not your typical conference poster. But hey, it was a lot of fun to make! And if you look at it, the bulk of the information from the paper is in it in visual form. It does its job.

The poster for SPIE 2012 will be more of a challenge. The paper discusses some of the unexpected consequences we ran into from our conversion from liquid nitrogen cooling to closed-cycle cooling (the topic of the poster shown, above). So there’s no clear road map on this one. It’s a scattered collection of problems, investigations, findings, and revelations we had along the way. In the end we got a new set of guidelines for good practices when designing closed-cycle cooled cryostats. But presenting it that way misses the real thrust of the paper: that we were clueless when we started.

“Clueless”. Actually, that’s inaccurate. We had clues. What we didn’t have was answers.

And that’s how I’d like to present it: as a whodunnit. Troubleshooting doesn’t follow a logical progression from A to B to C. It’s closer to a murder mystery, where the intrepid detective gathers clues, interrogates witnesses, forms a hypothesis, and eventually builds a case. This paper, and the associated poster, is really targeted at the troubleshooter rather than the instrument designer. It’s one thing to say, “Unless a cryostat is cooled below 77 Kelvin, the getter will be unable to pump nitrogen, and some other mechanism must be employed.” It’s another to say, “When we switched vacuum gauges, all of a sudden our cryostat couldn’t hold vacuum! It’s like we’d introduced some sort of leak into the system. But we never found anything with a leak check, and our RGA showed no uncharacteristic abundances. What was going on?!” A troubleshooter might read the first sentence and not see how it relates to a problem they’re having. But that same troubleshooter might read the second and say, “Hey! That’s just like my cryostat! How’d they solve this?!” Just like a murder mystery, the whole idea with a poster is to hook the reader (or viewer, in the case of the poster.) Everybody loves a good whodunnit.

Now I just have to figure out how to do that with a poster…

– Tom

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Fresh Out

Posted by Tom Benedict on 29/05/2012

A boat is a hole in the water into which you throw money, or so the saying goes. It’s not too far from the truth. All in all we spent more than I expected on our boat before we even got it in the water. A few nights ago, Rydra, who takes care of all our banking, came to bed and told me, “That’s it. Fresh out.” We had set a cap on how much we were willing to spend to get a boat in the water, and we’d hit it. (Actually, we’d gone past it, but she let it slide. It’s her boat, too, after all!)

Boats are a lot like cars this way. If you live somewhere with junk yards, owning and maintaining a car becomes a lot more affordable. Bust a side mirror, and you may spend ten bucks at a junk yard. Bust a side mirror where your only choice is to replace them in pairs with new parts, and you may be in the hole for a hundred dollars or more. With a boat, if you have a source of used parts to draw on, a surprising amount of money can be saved. Take a simple shackle. Boats use shackles like candy. If you’re scrounging them off of dead boats, you may have a buck or two invested in each of your shackles. Buy them new and they range from five to twenty dollars, depending. Given the number of shackles on a boat, that’s the difference between thirty bucks in shackles and several hundred.

We don’t have junk yards out here on the Big Island. We also don’t have a lot of beach cats. I had to buy most of the hardware for this boat new. Oh sure, I picked up as much as I could off of Ebay, but there are limits. If the person doing the selling doesn’t know much about boats, you may bid on something that’s described as “1 lot shackles, perfect for boat!” thinking you’re getting stainless marine fittings, only to find out you spent thirty bucks on a box of rusted galvanized shackles for trailers and chain. We bought some of our stuff off Ebay, but the bulk of it came from Murray’s, Sailcare, and Sailrite. It all just added up in the end.

Discouraging? Sure. But Rydra’s news came at a time when all the major and 99% of the minor work on the boat was done. I think she timed it that way on purpose.

The jib is still out, and the winds have been atrocious. So the boat is still sitting on its trailer in the yard waiting for a chance to sail. Yesterday my daughter had a ballet performance in Captain Cook, south of Kailua-Kona. We left the house in the morning with the heavy tradewinds hammering the trees. We don’t often go as far south as Captain Cook, so we spent some time at a really cool park down there. My oldest sat, reading her book, while the other two kids played. I stared out over the cliffs to the ocean, watching the wind on the water. I enjoy seeing my daughter dance, and I was looking forward to the performance. But I couldn’t help thinking how many months it had been since we got our boat, and still the ocean was out of reach. And now, I had no more resources left to throw at it.

The dance performance was a lot of fun. The theater group she’s part of put on a production of Alice in Wonderland using a mix of ballet, hip-hop, and tap. It went together far better than I thought it would, given that description. The choreography was impressive. Two of the dances combined two different dance forms in a single performance. I’m glad I was able to go.

On the way back I couldn’t help staring at the ocean, judging what the wind was like and guessing at how far we’d be able to sail in a day if we put in at Kawaihae or Puako or any of the other spots we passed along the way. As we drove I spotted several sails on the water. At least someone was out there. I just wished it could’ve been us.

By the time we got home the sun was starting to set, and a rainstorm had blown in. The kids were spotting rainbows and guessing at the treasures to be found at their ends. And that’s when my own questions were answered.


Ok, ok. I see the pot of gold. I can wait a little longer to go sailing with it.

– Tom

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Older and Wiser (or Older and Easily Fooled)

Posted by Tom Benedict on 27/05/2012

Older and wiser, or maybe just older and totally hoodwinked by my own design work. Time will tell. In any case, it was a little less than a week ago that Rydra and I managed to dismast our Pacific Catamaran while trying to raise the mast. Now, a week later, the boat is fitted out with new parts and a new mast raising system that should keep us from a repeat performance. The jib still isn’t back from Sailcare, so essentially we lost no time on the water. Not bad!

But let me backtrack…

When we broke the mast hinge, I really didn’t know if it would be possible to replace it. Spare parts for the Pacific Cat are almost impossible to come by. I do mechanical design and machining for a living, so making a new part wasn’t out of the question. But judging by the color of the mast hinge, I figured it was made out of bronze. I have scrap material of almost every kind of metal that comes across a machine shop floor, but no bronze.

When designing replacement parts, it’s always important to see what was there in the first place. If you replace a stainless steel part with an identical one made out of aluminum, it will break well before the old one did. Likewise if you replace all your high tensile strength bolts with stainless bolts, the stainless ones will fail long before the old bolts did. If the mast hinge truly was made out of bronze, I had two choices: go out and buy some bronze bar stock, or find a chunk of stainless. Neither prospect was very appealing.

Turns out it was never an issue anyway. I took the bits in to work to show to one of my co-workers. “Cast aluminum, huh? Colored to look like bronze?” I couldn’t believe it! The surface of the crack was clearly a white metal, not the more golden color of bronze. The coloring was only a paper thin layer near the surface. Part of me was a little peeved that the mast step had been colored like that, but the rest of me was pretty happy with the news. Aluminum I can deal with.

So over the weekend I made a new mast step hinge.

Broken Mast Step Hinge

No CNC on this one. It was all manual machining. Unfortunately it’s a lot uglier than it should be, because I tried to replicate the broken part rather than produce something that would do the broken part’s job. Note to self: Don’t trace ugly stuff onto metal prior to saw cutting, and expect to make anything but an ugly part. But the lesson is learned: If I ever have to replace this hinge, I’ll design the new one from scratch.

The new mast step hinge is made from 6061-T651 aluminum; common fare in a machine shop, and a lot tougher than cast aluminum. Cast metals tend to be brittle, and will crack before they bend. Metals that are ductile tend to bend before they will crack. 6061 is an alloy of aluminum that includes other metals to increase its mechanical characteristics (tensile strength being one of the more important ones). T651 heat treatment increases hardness, but also increases how brittle the aluminum is. 6061-T651 will bend, but only up to a point. Then it cracks. But it bends a heckuvalot more than cast aluminum! Structurally, this was a win.

The original hinge pin was a stainless tube, which was peened into place once it was installed. This was a major PITA to get out. The tube had been so deformed over the years, it wouldn’t just slide out. I had to pound it out 1/8″ at a time, cut that section off, then pound it back the other way to cut that side off. After going back and forth about twenty times it finally gave up the ghost and the last little nubby of tube popped out. I replaced it with a solid steel rod, held in place with split rings. This is how the Prindle mast step pivots. Good enough for me.

So we were back in business, but no better off than before. Rather than risk a repeat performance of the downed mast, I sought to remedy the root cause. So during my spare time over the week I designed a new doodad for the boat:

Mast Step Assist - CAD

It’s a contraption that creates a virtual pivot axis for the mast that will constrain the mast to the fore-aft plane. It’s strapped down to the boat just behind the mast step hinge. The geometry of the side plates locates the eyebolts along the axis of the mast hinge. Once the thing is strapped down to the deck of the boat, side stays are attached between the mast and the eyebolts. This prevents the mast from swinging off to one side the way it did during our last disastrous attempt to raise it.

The width of the crossbeam is critical. It places the eyebolts so the straps coming up from the trailer attach to the eyebolts at a 10 degree angle off vertical. This is the same angle the side stays come off the mast. This keeps the side plates from being subject to any torquing motion. All the tension forces acting along the stays should go straight down the straps to the trailer.

I had most of the material to make this in the scrap box. But as with any scrap box project, the design evolved to match the materials available. The feet at the base went from 1″x1/4″ to 1″x1/2″ because I had a good sized bar on hand. The side plates went from 1/4″ to 3/16″ thick, and were clipped a little deeper on the rear corners. The cross tube and eyebolts came from Ace Hardware. All in all I had less than $30 rolled into it. After a test fit on the boat I added some split lengths of 1/2″ fuel line to the bases to make rubber feet so it wouldn’t mar the deck any more than it already is. Here it is installed and ready for use:

Mast Step Assist Installed

The wind is still too gusty to try to use it, but it was nice to see it in place and ready to go. Since our boat is rigged with two pairs of trapeze wires, we plan to use one pair as the baby side stays for raising the mast. Once the mast is up and the real stays are all locked in place, the trapeze wires are removed from the doodad, and are clipped back onto their shock cords for use on the water.

The only job left is to give this thing a name other than “doodad”, “contraption”, or “thingy”. Mechanical design and machining I can handle. Names? Er…. HELP!

– Tom

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