SSE – Covering Beings

Got a few hours of building time this weekend and I started covering the SSE. I really dread covering, so I tend to put it off and find other things to do. I am at the point on the SSE where I ran out of other things, so covering begins.

This will be my third covering job and my first time working with Monokte as opposed to AeroLITE (Stevens Aero branded version of Solite) which I used on Stella and my SA RV-4. I had two rolls of Monokote  (one white and one red) lying around that I was intending to use on my SIG LT-40 (I lost interest in that project once I got past the trainer stage of flying and never did get the plane covered).

I’ve read all the flame wars of Ultacote vs. Monokote and bought the Monokote on the advice of a friend who was helping to get started in RC. So far, I am finding Monokote to actually be a bit easier to work with than AeroLITE. Mainly, this is because it is a bit thicker making it easier to handle and less prone to burn-through when shrinking. It also does not fold over and stick to itself the way AeroLITE does. It clearly is a lot heavier than AeroLITE and would not be appropriate on a small park flyer. I have not tired any compound curves yet, which most seem to claim is Monokote’s biggest weakness (at leas as claimed by the Ultracote crowd!).

So far, I have the rudder and elevator covered in red and the rear half of the fuse bottom in white.

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I’m giving my covering job a passing grade so far, but barely. Most of my problems are related to surface prep. I spent way too much time sanding and filling (see my Lessons Learned post), but as you can see, it really did not pay off. Simply put, I need to develop a lighter touch when working with balsa during the construction phase. This includes not only a lighter touch when sanding, but also more care in handling the pieces prior to covering.

I tend to be a bit too critical of my own work, but I also look at every project for learning opportunities and for things I can do better next time!

SSE Lessons Learned

I continue to plod slowly long on my SSE build. I have the basic construction completed and I am just about ready to start covering and final assembly. While I still have not learned how to get my builds done as quickly as a lot of the other guys I see posting on RC sites, I have learned quite a few lessons along the way.

Lesson 1: Be Selective with Kit Supplied Balsa

The 1/16″ sheeting supplied with the kit for the wing D-Tubes (the sheeted portion of the wing ahead of the spar) turned out to be a bit marginal, with a large knot running through several sheets in the same place. I ignored this and used them anyway, only to find that those knots caused a large local dimple to form between the wing ribs. Note this was not a “starved horse” kind of sagging you sometimes can get between the ribs, but more of a dimple localized around the knot. Being the fussy builder that I am, I decided to fill the dimple with a bit of balsa filler. This worked great on one wing panel, but not so good on the second, leading to Lesson 2.

Lesson 2: Know When To Stop Fussing

When fussing with the dimple on the second wing panel, I kept filling and sanding and filling and sanding trying to get the surface to blend smooth. All this filling and sanding lead me to sand the surrounding sheeting too thin, and I ended up poking a hole through the balsa. Ughh! I originally tried to patch just the local area, but this lead to another cycle of fussing. So in the end, I gave up and just carefully cut the sheeting off the outer two bays and replaced it with new wood.

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The final product is acceptable, but I do have a but of starved horse look between the ribs. This is a result of too much sanding trying to get the surface smooth. which leads to Lesson 3.

Lesson 3: Less Is More When Sanding

When it comes to sanding, always remember that less is more. You can always go back later and take another swipe or two, when you’re really convinced that you need it, but you can’t put back material (at least not easily). Even though I was careful to use a long flat bar, too much sanding leads to thinning of material directly over the ribs producing a wavy look in my wings.

I also ran into a problem when sanding out the fuselage hatch. When blending the front of the hatch smooth, I was not paying enough attention to the “other end” of the sanding bar, which in turn lead to a nasty groove being cut near the back of the hatch from the back corner of the sanding bar. This lead to another cycle of filling, sanding, and fussing (see Lesson 2), which again resulted in material being sanded too thin. In this case, I plated on some 1/16″ balsa scraps to build material back up, and then blended it smooth. You can see below that I misted on a very light coat of gray primer to help guide my sanding (i.e.; the primer is left behind in low spots).

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Once again, what I ended up with a less than perfect, but hopefully acceptable (we’ll see after the covering is applied). Which leads to the most important lesson learned yet …

Lesson 4: Any Mistake Can Be Fixed

A good friend who helped me to get started in RC once told me: “Don’t worry if you make a mistake, any mistake can be fixed”. I repeat that mantra to myself all the time while I am building, especially when things start to go bad. Mistakes are part of the building process. We all make them, even the best builders out there. Mistakes can be fixed and they can be a learning opportunities for the future. Sometimes they cost us some money (if a new part or material needs to purchased), but mostly they just impact time (and maybe a little pride) and it is part of the overall experience. Remember that this is a hobby and we do this for fun, so don’t fret if something goes wrong, just fix it!

Fan Trainer Fiasco

One of my projects from last summer was an attempt at a foamy scratch building with a Fan Trainer EDF built from Dollar Tree foam board. I patterned it after the 150% scaled up version of the plans found in this build thread: http://www.rcgroups.com/forums/showthread.php?t=426281.

This was my first attempt at both EDF and at building with foam. The building process went well and I kind of enjoyed working with foam.

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The total investment in foam was about $5 (including scrap and re-work). I powered it with a Detrum 70mm Fan combo from HobbyPartz.com which includes the fan, motor, ESC, and servos for under $50. All in, with batteries, and a 4 channel receiver, total investment was under $100.

Unfortunately, it did not survive its maiden flight. The wings were simply not stiff enough and fluttered badly. Apply enough power to keep the plane flying, and the wings flapped like a hummingbird. Back off the power, and there was virtually no control. I ended up lawn-darting and disintegrating everything from the wings forward (sorry, no picture of the damage).

Oh well, nothing ventured nothing gained. The electronics and fan escaped unscathed, so the total loss was under $10 (and a little bit of pride). I have a few ideas for how to use the fan and other bits from this attempt in a new creation!

Falling Into A Pattern

Well just like previous years, it looks like I got a way from posting as the summer went on last year, and now I am starting up again as we head towards spring. I don’t lose interest in RC planes or flying, but between work, holidays, and family activities, I find little time left for posting in the fall and winter. I have been putting time in here or there working on various RC project and will post more details (with pictures) soon. For now, I just wanted to at least get one post up to ensure that my site is still working!