VonSquid's SQ2000 Adventure

Building the SQ2000 Kit Plane

Hey folks,

My website has become so outdated that many have wondered if the project is still alive.  Yes, it’s alive, and progressing well, albeit very slowly.  But it’s definitely time to update the website, so here we go.

This new “blog” style site will be chronological, and I promise to do a better job of updating it.  I will begin populating it from the beginning (way back in 1998 (yikes!)), working toward the present.

As with any blog, the newest entries will be at the top.  If you want to see posts related to certain topics, just pick one of the Categories at right.  There is also a Tags feature which may or may not prove useful.

In the mean time, the old site is still available here.

Epoxy Report

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Hudco's Clearstream 9000 laminating resin

Now that I’ve done scores of layups and can proclaim myself an expert at room temperature wet layups, I can say that I’ve been very pleased with the performance of Hudco’s Clearstream laminating resins.  I received two different hardeners with my initial shipment, a slow and a fast, as you’d expect.  Since temperatures in the Seattle area are below the national average I received more of the fast hardener, per Stan Montgomery’s input.  Typically I can get about 45 minutes of working time out of a fast batch.

This resin is low odor, easy to work with, and cures at relatively low temperature.  I haven’t tried many of the other epoxy resins popular with kit builders, so I can’t site any direct comparisons, but if I were to buy more epoxy, I would certainly seek out more of this stuff.

A friend of mine used to work for a large adhesives company – one that supplied Boeing with adhesives and laminating resins – so I got some of his samples from time to time.  I did a side by side comparison of his laminating resin that met Boeing specifications, and I found the Clearstream to be better for the amature builder: odor was lower, easier curing, and slightly better peel strength in my unofficial bench test.

I did call Hudco to order some more epoxy at one point, but was shocked at the price (nearing $200/gallon as I recall) which is much higher than a gallon of say West Systems.  Stan Montgomery ended up sending me some directly without charge, which was a nice gesture.

I’m not sure how Glassic Composites selected Hudco as their epoxy supplier, but I suspect Stan had some connections with the company.

Last time I checked their website, I could find no evidence of their Clearstream 9000 laminating resins.  Perhaps they discontinued the line.

Inevitably I’d need to move my project to a hangar at some point. I wasn’t in critical need yet, but I began doing some investigation in 2002. The most convenient airport for me was Paine Field in Everett because that’s where the Boeing plant where I work is located, and it’s the closest to my house. Unfortunately the hangar options weren’t looking too good. The rental hangars were old with nothing more than a single light bulb hanging from the ceiling… and there was a one-year waiting list. Furthermore, airport policy is that no maintenance is to be performed in those hangars. There were also some privately owned hangars on the field, but buying one wasn’t really in my budget, even if I could find one for sale.

Arlington Airport was another option.  Their hangars are pretty old too, but I believe it was OK to work in them. Unfortunately Arlington is a good 40 minute drive from my house. On the plus side, Arlington has good homebuilder roots as the host of the Northwest EAA fly in and home of The New Glasair.

My last practical choice was Harvey Field. Not quite as far away as Arlington, but not many hangars available over there. Plus it’s located in a flood plain. That’s not really a “plus” at all, is it?

By pure luck I happened to surf to the Paine Field web site one day and noticed an announcement: they were considering constructing more hangars if they could get enough tenants to sign rental agreements. So I hurried down there to get the scoop. Jackpot!  They were planning to build brand new T-hangars and rectangular hangars of various sizes, complete with overhead lighting, 20 amp electrical circuits (4 outlets), sprinkler systems, and fully rated for aircraft maintenance (and construction). I put my deposit down right away. They easily got enough tenants to commit (I think there’s a waiting list now) and the project went forward. It took a little longer to complete than they had planned, but that was fine by me. I loaded the airplane onto a flatbed truck and hauled it to its new home in late June, 2003.

One thing I knew was going to be a problem was electrical power. The new hangars did not have 240VAC available, which is what my air compressor requires. I talked to the airport office about adding a 240VAC circuit for me: they were amenable, but it would have cost me over $500. I asked them if they were crazy because I could buy a new 120VAC compressor for less than that. They said they weren’t crazy and I just decided to go ahead and buy a new compressor. Unfortunately the story doesn’t end there.

Periodically when the compressor would start up, it would trip the circuit breaker. This didn’t affect other hangars thankfully, but the circuit breaker panel was in a locked electrical room at the end of the hangar row and I had to call airport maintenance to reset it. Invariably it would trip on a Friday evening when the maintenance people had gone for the weekend, leaving me powerless. I could not find any explanation as to when the breaker would trip and when it wouldn’t. It wasn’t temperature related, or other loads on the line. 9 times out of 10 the compressor would start up just fine. It was weird, and very frustrating for me and for the airport people.

Eventually enough was enough and I got permission to run a new 240VAC circuit into the hangar. They said I could do it myself provided it met county codes. So I did. The good news was that my hangar was only two units away from the electrical room, so pulling new wires through the conduit was pretty easy (with the help of some friends and their scaffold). The bad news was that panels were fed by 3-phase power, common for commercial buildings apparently. For those of you familiar with such things, you know where I’m going with this: you can’t get a 240VAC circuit out of a 3-phase feed. I could get a 207VAC circuit, but that wouldn’t do me much good. So after a few days and a few calls to the Paine Field Electricians we settled for a dedicated 120VAC circuit wired to a 30 amp breaker. Problem solved, although my new compressor doesn’t have quite the “umph” of my 240VAC compressor, which now sits quietly in the garage.

Aside from a rather sizeable monthly rent, the only other problem I’ve had since moving to the hangar is heat. The airport fire department will not allow heaters of any kind in the hangars. Heck, I even got a nasty “code violation” letter the other day because they found a small electric heater during a surprise inspection. Never mind that it was sitting on a shelf, unplugged. So winter work has slowed to a dead crawl for now.

In June 2002, as my fuselage work was drawing to a close (yeah, right), I figured it was time to order some more kit components. Rather than mess around with ordering just one or two subkits, I decided to bite the bullet and order everything. A large amount of cash to layout all at once, but I didn’t want to take a chance on KLS Composites going out of business before I had everything I needed. So I ordered the wing kit (rib & spar wing, not the foam core version), canard kit, cowling kit, and strake kit. In late July 2002 I got the call that my parts were ready and on their way westward.

Stan Montgomery gave me the crate dimensions, approximate weight, and the tracking information for the trucking company. I was to pay a crating fee and the shipping cost. This time they used Estes Express/G.I. Trucking as the carrier. G.I. wasn’t quite as flexible with regard to delivery options (i.e. “we’ll be there between 8AM and 5PM), so rather than try to coordinate an uncrating party like last time, I opted to have them hold the crate at their depot in Auburn, WA. Then, when it was convenient for me, I rented a truck and drove down to get it. One thing Stan failed to mention when he gave me the crate dimensions: It had a “chimney” to fit the winglets. The chimney turned out to be about 2 inches taller than the truck box. Hmmm, now what? The crate was long enough that we decided to shove it in as far as it would go, and tie a rope around the back end. Needless to say, it was a rather nerve-racking drive home (about 50 miles) with $20,000 of airplane parts dangling out the back of the truck. But I made it home with no problems–just a few weird stares.

The crate also turned out to be way heavier than Stan had estimated. It weighed nearly 1200 pounds if I recall correctly. Moving all that weight from Tennessee to Seattle translated into a whopping C.O.D. shipping fee of $1787. When I told Stan about that, he promptly waived the $200 crating fee, which was nice, but ouch.

Since it worked so well last time, and because the crate was so heavy, my buddy Chris and I dismantled the crate inside the truck and just removed the pieces one-by-one. Suddenly my garage was full again.

The last part of the fuselage joint, at least the inside work, involved the hatch area up in the nose.  This panel will eventually be cut out and turned into a removable access hatch to get to the electro-mechanical equipment that will be installed up there.  Or a jacket.

The process here was the same as before.  First a single ply across the joint, then some foam core to fill the joint, then 2 plies over the whole mess.  The only difference in this area was the use of 1/4″ high density core instead of the 3/4″ core I had be using.  I like this 1/4″ stuff better anyway since it’s easier to shape.

After the basic layup was complete, there was an extra step to build and attach 2 stiffening ribs to the inside of the hatch.  Since it will be removable, these will allow the hatch to keep its shape.  The stiffeners were built out of the same 1/4″ high density foam core, then bonded in place.  The edges were rounded off, and the joint radiused with an epoxy micro mixture, then 2 plies of S2 glass were added over the top.

The S2 glass is a special weave that allows it to form nicely over tight areas and compound curves.

Overall, I think the installation came out pretty good.  In the below photos, the fuselage is upside-down for the first 3 photos, and upright for the last one.

Joining the fuselage halves at the upper joint was identical to the lower joining process, so I won’t bore you with all the details… I’ll just put a few photos at the end.

But before I could actually get started, I decided it would be a good thing to invert the fuselage first.  I guess I could have done the job over-my-head, but that would have been messy.  And insane.

So in enlisted my buddy Mike Wagnon to help me invert it.  While not particularly heavy, it would have been difficult for me to do myself, given its size.

Once inverted, I build a little saw horse cradle to support the nose so that it wouldn’t tip over while I crawled around inside.

So then it was back inside the fuselage for me (oh, my aching back), to repeat the process of ply – core – plies.  Again, the most time consuming part of the joining process was constructing the foam core sections so that they nestled just perfectly into the joint valley.

With the lower fuselage joint nearly complete, the last step was to add 2 plies of EBX-1200 (if I recall correctly) fiberglass cloth over the top of the joint.   With my ever-increasing fiberglassing skills, this task wasn’t particularly challenging.

For smaller layups, I found that wetting the fiberglass cloth with epoxy resin was easier when accomplished on the work bench.  But for larger pieces like these, I prefer to do the layup in place.

The first ply of EBX-1200 cloth was laid up over the exposed foam core, after filling the open cells with a wet micro mix, of course.  A 1 – 2 inch overlap on all sides was the standard.  Then another ply on top of that one, with anothere 1 -2 inch overlap.

Apply a final peel ply, and let the whole thing cure.  Voila! Lower joint complete.

A side note here for those of you with bad backs: don’t build this airplane.  I don’t have a bad back, but after several hours hunched over in the fuselage working on this joint, I sure felt like I did.  And I was only half way done.

Also, get yourself a set of knee pads.   You’ll thank me later.

Now that the lower fuselage joint was essentially bonded together, the next step was to strengthen the joint.  This is achieved by filling the “valley” with rigid foam core, then glassing over the top.  For this project, the Builders Manual called for medium density 3/4 inch core.  Although lower density than the 1/4 inch stuff I was using to make bulkheads, I found this foam more difficult to work with.  It was difficult to sand, although responded fairly well to rasp files.

Trying to fabricate one long piece of foam to fill the entire ~10 foot long valley would be have been ridiculous, so I attacked it 16 inches at a time.  Each 16 inch (approximately) section of core was carefully filed, shaped and sanded so that it fit exactly into the valley.  This was a very iterative and time consuming process of shape-test-shape-test-shape.  Once I was satisfied with the fit, the foam section was bonded in place with a wet mix of epoxy micro, with some dead weight to keep it in place.  I prefer Play Sand for this job.

 

 Then the process was just repeated over and over until the entire lower valley was filled up to the area of the NACA inlet.

I had to quit working in October, about 120 hours into the project, when it became too cold for epoxy work. I should have planned ahead back when I was in the “preparing the workshop” phase, but I completed the workbench just days before the kit arrived, and by then my mind was on the airplane–not on heaters.

Nevertheless, mother nature caught up with me, the ambient temperature continued to decline, and I could procrastinate no longer.

I considered many heating options for the garage and my first solution was to purchase a 4000 watt, 240V electric heater from McMaster-Carr. According to their chart, 4000W should have been plenty to heat the volume of my garage. I ordered it. It arrived. I plugged it in to the outlet that I had wired especially for my compressor, and off it went. But to my disappointment it made more noise than heat (the fan wasn’t balanced very well). Clearly, it wasn’t going to keep my garage in the mid 70′s throughout winter, so I sent it back.

I considered tapping into my house furnace and running a duct to the garage, but that presented a problem with the thermostat (being located in my living room) not to mention the hassle of running additional ducting and cutting through walls, etc. There were plenty of propane heaters on the market that would suit my needs, but I dreaded the repetitive task of refilling propane tanks. Finally I settled on a natural gas convection heater, which I also purchased from McMaster-Carr. This heater had a 60,000 BTU/hour output and would be much more convenient since I had a gas line running nearby. So I ordered it, and while awaiting its arrival I ran a gas line into the garage. I chose a convection heater because I wanted to heat the entire volume of air in which I was working, as opposed to a radiant heater which primarily heats objects in it’s path. Convection heat is much more even, and better suited for composite work.

My garage is insulated so heat loss was not a huge concern, but just to boost efficiency I insulated the garage door too.

The natural gas heater works great, and burns very clean, but since it’s unvented and I really didn’t want to kill myself, I bought a carbon monoxide detector to monitor any build up of that stealthy, toxic gas. It has a digital readout so that I can see the actual PPM concentration of CO in the air, which is pretty neat. Happily, CO levels are well within the acceptable range when running the heater.

Finally, for local heating, I purchased a small electric space heater (1500W max). It was inexpensive ($25 at Home Depot) and works great for curing things inside the fuselage. I just set it inside, plug it in, seal up the aft fuselage opening, and it keeps things nice and warm in there. Then I can shut down the gas heater when I’m done working for the evening and let the local cure continue.

With all the bulkheads now complete, I could move away from the workbench and onto the airplane as I began Section 2, Chapter 9 of the Builder’s Manual.  As the title suggests, this is the point where I permanently bonded the 2 fuselage halves together.

Let me preface the chapter by saying this was a major task, and took way, way, way longer than I imagined.  I partially attribute this to the weather turning colder, and my generally lower enthusiasm for working in a cold garage.  Regardless of my own desires for comfort, working with epoxy resin requires an environment of at least 70°, so a space heater was now a necessity if I was to continue working through the winter.  But you can read about that in my Building in the Winter entry.

Before actually bonding anything together, the normal first step would have been to align the 2 fuselage halves. Recall, however, that I took care of that a few months earlier when I was still awaiting the arrival of my epoxy (see Aligning the Fuselage Halves) so I could jump right into the joint (sounds like a blues song).

The basic concept of the fuselage joint was pretty straight forward;  a single ply of fiberglass is laid up across the joint valley, then some foam core is bonded in, and another ply of fiberglass covers the whole mess.  After that, I could cut off the flange (mohawk) and fill the remaining gap flush.  Sounded simple enough, but it sure took a long time – highly attributable to my meticulous manner I suppose.

Typical of composite construction, when two pieces are to be joined together, the core is tapered down to zero so that a solid laminate joint can be achieved.  I referred to this area as the “valley.”

I started by sanding the valley area by hand to remove any imperfections and high spots.  Next, some light weight filler (epoxy/microballoon mixture (“micro”)) was applied to any small voids or low spots so that I wouldn’t have any trapped voids in the joint.  After a full cure, the filler was sanded smooth and flush.

Then comes the messy part: a heavy ply of fiberglass, about 12″ wide, is laid up across the joint (is it “laid up” or “layed up?”) and allowed to cure with a top layer of peel ply.  After cure, the peel ply was removed.  I started at the nose and worked my way aft over the course of a few days.

Layup over the lower fuselage joint.