Sig Astro Hog - 1st Build
01-27-2012, 04:24 PM
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Sig Astro Hog - 1st Build
Hello Gents! Welcome to my first build thread!!!
I chose the Sig Astro Hog kit for my first build because it has a constant-chord wing (making it easier to skin and cover) and its construction seemed fairly straightforward. I also like its looks. It has a similar basic shape to the PT-19, so I'm planning to cover it in the blue and yellow trainer color scheme. I considered modifying it for dual cockpits, but I think it would be best for my first build to just follow the plans as written and leave the bashing for the 3rd or 4th kit.
I feel it only fair to warn you all that I suck at documentation. I get so caught up in building that I forget to stop and take pictures, so a lot of the pictures I post (at least at first) will be after-the-fact shots. Hopefully I'll get better at it as I go.
I'm using a magnetic building system, and I purchased a magnetic fixture kit from Paul Johnson at www.airfieldmodels.com. Paul was awesome to work with, and he happily answered all my stupid questions. My board is a 24" x 80" sheet of 22 gauge galvanized steel, and it's clamped to a hollow core door. The whole assembly lays on the workbench in my woodworking shop. The bench itself is very flat, but I built it with a raised edge that creates a recess for a sheet of 1/4" hardboard, and it turned out that the edges are a smidgen (no more than 1/32") higher than the hardboard. When I laid the door on top of it, the edges produced a slight bow, but that was easily fixed by sliding a couple sheets of heavy paper between the door and bench top, so now it's good & flat.
I'm also using yellow wood glue for most of the kit assembly. Like most people, the CA fumes give me a headache, so I'm only using it where it would be difficult to secure something in place long enough for wood glue to dry thoroughly. I'm also comfortable working with wood glue because I've done quite a bit of woodworking, though I have to remember that the old "ain't no such thing as too much glue" adage doesn't apply when you want to build something as light as possible without sacrificing strength, and learn to use it a bit more sparingly.
Otherwise, it's all pretty much standard stuff, so on to the building!
Step 1: Read the construction manual - This step isn't a problem for me, as I actually enjoy reading the manuals. I haven't been involved in RC flying for very long, but I've built lots of static aircraft and car models, and I've always enjoyed the building process itself. Sometimes I even download the construction manuals for RC models I think I'd like to build and read through them just for fun.
Step 2: Read the manual again - I actually read it 3 times. After the 1st read-through I went back and made notes on earlier steps that affected later steps. Between the 2nd and 3rd time I searched for and found a few other Astro Hog build threads, read through them, and made notes based on the other builders' experiences.
Step 3: Inventory and organize - The first two photos show all the sticks, sheeting, and hardware arranged on cardboard sheets laid on top of my table saw, and the die-cut sheets laid on one end of my building board. There were no parts missing or broken, though some of the sticks had some small dents, gouges, or other minor damage. None of the damaged spots appears to be so large that I won't be able to work around it, but there are several hobby stores nearby with good wood selections, so I should have no trouble finding replacements.
Step 4: Start building! - The manual starts with construction of the wing panels, so I started with the left one. The first step was to cut spar doublers and glue them to the upper and lower spars. The kit provides 6 x 1/2" x 1/4" x 30" balsa sticks for this. 4 for the spars, and 2 to cut the doublers from. None of them were straight, but none of them were so warped as to be unusable, so I chose the 4 straightest for the spars and cut the doublers from the straightest sections of the remaining 2. The 4 I chose as spars were all bowed along the narrow dimension, and I was able to cut the doublers so that they were bowed that way as well (one of them had a swirl near its center that caused a significant crook in the wide dimension, so I cut the doublers from either end). I arranged the spars with the concave side up and glued on the doublers with their concave side down, so that they would straighten each other as much as possible, weighted them down, and left them overnight to dry. Unfortunately, I forgot to take any pictures of that part, but it would have been pretty boring anyway.
The next step was to glue plywood doublers to the 2nd, 3rd, and 4th ribs to stiffen the area where the landing gear blocks will be mounted. When I glued them on I aligned the edges of the doubler with the edges of the rib, which resulted in some misalignment with the spar notches. In retrospect, I should have more closely aligned the notches instead, as a fair amount of sanding was required to get the ribs to line up correctly between the LE and TE on the plans, and I ended up with about a 1/32" gap between the front edge of the spar and the edge of the rib notch. I was able to easily fill them in later with thick CA, but I would have preferred a more snug fit. So...lesson #1 learned!
The following day I was ready to start assembling the wing, so I cut out the left wing panel plan, taped it firmly to my board, and taped a sheet of clear plastic over that. Next I removed all the ribs from the die-cut sheets and cleaned up the spar notches with a hobby knife. I then laid the bottom spar on the plan, clamped it in place with magnets, and started fitting the ribs to it one at a time. The magnets I'm using do a fine job of holding whatever you clamp between them square to the board, but I still checked each one with a steel square to be sure. Once all the fitting was done, the magnets made it simple to carefully slide each rib off the spar without moving the magnets, apply wood glue to the spar notch, and slide it back in place between the magnets. I still checked each rib for square, though, before turning off the lights and going to bed.
This morning I adjusted the notches in the tops of the ribs to fit the upper spar. The fit was actually really good right off the bat, so very little adjustment was needed before I glued it in place with wood glue. In the photo of the wing you may notice that the assembly tabs at the TE of the 3 closest ribs are slightly elevated from the board. I noticed it as I was taking the photo and figured out that it was caused by a slight bow in the upper spar that pushed the inboard end of the spar forward a bit, twisting the wing. I was able to correct the alignment by using some of the magnetic fixtures I bought from Paul to push the end of the upper spar into alignment with the lower spar, removing the twist. Afterwards, I cut out and glued the dihedral angle gauge to a piece of scrap balsa, sanded the edges to the correct angle, and used it to align the root rib. I didn't have enough room between the ribs to place magnets to hold the root rib securely at the correct angle, so I used thin CA to glue the rib in place. I had clamped the dihedral gauge between to magnets to free my hands to hold and glue, and it worked out nicely.
So that's where I am now. I'm a bit concerned about the wing twist caused by the upper spar. Even though I had forced it into alignment before the glue was dry from gluing in the top spar, I'm not confident that alone will prevent it from springing back when I un-clamp everything. The final photo is from the construction manual, and it shows the W1A piece glued between the W1 and W2 ribs, which will probably help somewhat, but I'd love to hear any suggestions you guys may have as to how to brace the wing so that the twist doesn't return. Actually, now that I think about it, the wing will be fully balsa sheeted on the top and bottom from the root to the 5th rib, and partially sheeted from there on out. Would it be safe to assume that such a small amount of twist can be corrected with the sheeting?
That's it for today, gents. Thanks for reading along! It may be a few days before I'm able to get back into the workshop, but I'll post an update as soon as I can.
~ Ron
I chose the Sig Astro Hog kit for my first build because it has a constant-chord wing (making it easier to skin and cover) and its construction seemed fairly straightforward. I also like its looks. It has a similar basic shape to the PT-19, so I'm planning to cover it in the blue and yellow trainer color scheme. I considered modifying it for dual cockpits, but I think it would be best for my first build to just follow the plans as written and leave the bashing for the 3rd or 4th kit.
I feel it only fair to warn you all that I suck at documentation. I get so caught up in building that I forget to stop and take pictures, so a lot of the pictures I post (at least at first) will be after-the-fact shots. Hopefully I'll get better at it as I go.
I'm using a magnetic building system, and I purchased a magnetic fixture kit from Paul Johnson at www.airfieldmodels.com. Paul was awesome to work with, and he happily answered all my stupid questions. My board is a 24" x 80" sheet of 22 gauge galvanized steel, and it's clamped to a hollow core door. The whole assembly lays on the workbench in my woodworking shop. The bench itself is very flat, but I built it with a raised edge that creates a recess for a sheet of 1/4" hardboard, and it turned out that the edges are a smidgen (no more than 1/32") higher than the hardboard. When I laid the door on top of it, the edges produced a slight bow, but that was easily fixed by sliding a couple sheets of heavy paper between the door and bench top, so now it's good & flat.
I'm also using yellow wood glue for most of the kit assembly. Like most people, the CA fumes give me a headache, so I'm only using it where it would be difficult to secure something in place long enough for wood glue to dry thoroughly. I'm also comfortable working with wood glue because I've done quite a bit of woodworking, though I have to remember that the old "ain't no such thing as too much glue" adage doesn't apply when you want to build something as light as possible without sacrificing strength, and learn to use it a bit more sparingly.
Otherwise, it's all pretty much standard stuff, so on to the building!
Step 1: Read the construction manual - This step isn't a problem for me, as I actually enjoy reading the manuals. I haven't been involved in RC flying for very long, but I've built lots of static aircraft and car models, and I've always enjoyed the building process itself. Sometimes I even download the construction manuals for RC models I think I'd like to build and read through them just for fun.
Step 2: Read the manual again - I actually read it 3 times. After the 1st read-through I went back and made notes on earlier steps that affected later steps. Between the 2nd and 3rd time I searched for and found a few other Astro Hog build threads, read through them, and made notes based on the other builders' experiences.
Step 3: Inventory and organize - The first two photos show all the sticks, sheeting, and hardware arranged on cardboard sheets laid on top of my table saw, and the die-cut sheets laid on one end of my building board. There were no parts missing or broken, though some of the sticks had some small dents, gouges, or other minor damage. None of the damaged spots appears to be so large that I won't be able to work around it, but there are several hobby stores nearby with good wood selections, so I should have no trouble finding replacements.
Step 4: Start building! - The manual starts with construction of the wing panels, so I started with the left one. The first step was to cut spar doublers and glue them to the upper and lower spars. The kit provides 6 x 1/2" x 1/4" x 30" balsa sticks for this. 4 for the spars, and 2 to cut the doublers from. None of them were straight, but none of them were so warped as to be unusable, so I chose the 4 straightest for the spars and cut the doublers from the straightest sections of the remaining 2. The 4 I chose as spars were all bowed along the narrow dimension, and I was able to cut the doublers so that they were bowed that way as well (one of them had a swirl near its center that caused a significant crook in the wide dimension, so I cut the doublers from either end). I arranged the spars with the concave side up and glued on the doublers with their concave side down, so that they would straighten each other as much as possible, weighted them down, and left them overnight to dry. Unfortunately, I forgot to take any pictures of that part, but it would have been pretty boring anyway.
The next step was to glue plywood doublers to the 2nd, 3rd, and 4th ribs to stiffen the area where the landing gear blocks will be mounted. When I glued them on I aligned the edges of the doubler with the edges of the rib, which resulted in some misalignment with the spar notches. In retrospect, I should have more closely aligned the notches instead, as a fair amount of sanding was required to get the ribs to line up correctly between the LE and TE on the plans, and I ended up with about a 1/32" gap between the front edge of the spar and the edge of the rib notch. I was able to easily fill them in later with thick CA, but I would have preferred a more snug fit. So...lesson #1 learned!
The following day I was ready to start assembling the wing, so I cut out the left wing panel plan, taped it firmly to my board, and taped a sheet of clear plastic over that. Next I removed all the ribs from the die-cut sheets and cleaned up the spar notches with a hobby knife. I then laid the bottom spar on the plan, clamped it in place with magnets, and started fitting the ribs to it one at a time. The magnets I'm using do a fine job of holding whatever you clamp between them square to the board, but I still checked each one with a steel square to be sure. Once all the fitting was done, the magnets made it simple to carefully slide each rib off the spar without moving the magnets, apply wood glue to the spar notch, and slide it back in place between the magnets. I still checked each rib for square, though, before turning off the lights and going to bed.
This morning I adjusted the notches in the tops of the ribs to fit the upper spar. The fit was actually really good right off the bat, so very little adjustment was needed before I glued it in place with wood glue. In the photo of the wing you may notice that the assembly tabs at the TE of the 3 closest ribs are slightly elevated from the board. I noticed it as I was taking the photo and figured out that it was caused by a slight bow in the upper spar that pushed the inboard end of the spar forward a bit, twisting the wing. I was able to correct the alignment by using some of the magnetic fixtures I bought from Paul to push the end of the upper spar into alignment with the lower spar, removing the twist. Afterwards, I cut out and glued the dihedral angle gauge to a piece of scrap balsa, sanded the edges to the correct angle, and used it to align the root rib. I didn't have enough room between the ribs to place magnets to hold the root rib securely at the correct angle, so I used thin CA to glue the rib in place. I had clamped the dihedral gauge between to magnets to free my hands to hold and glue, and it worked out nicely.
So that's where I am now. I'm a bit concerned about the wing twist caused by the upper spar. Even though I had forced it into alignment before the glue was dry from gluing in the top spar, I'm not confident that alone will prevent it from springing back when I un-clamp everything. The final photo is from the construction manual, and it shows the W1A piece glued between the W1 and W2 ribs, which will probably help somewhat, but I'd love to hear any suggestions you guys may have as to how to brace the wing so that the twist doesn't return. Actually, now that I think about it, the wing will be fully balsa sheeted on the top and bottom from the root to the 5th rib, and partially sheeted from there on out. Would it be safe to assume that such a small amount of twist can be corrected with the sheeting?
That's it for today, gents. Thanks for reading along! It may be a few days before I'm able to get back into the workshop, but I'll post an update as soon as I can.
~ Ron
01-27-2012, 06:58 PM
#2
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RE: Sig Astro Hog - 1st Build
You have no idea what you've gotten yourself into!!!!!
When you have 2 warped spars mount them so that the warps work opposite each other - both bows (upper and lower) to the outside. Same goes for spar doublers when the spars are straight - glue them so that they oppose each other.
You might check out Hog Bipe build threads too as the Hog and the Bipe share quite a bit.
When you have 2 warped spars mount them so that the warps work opposite each other - both bows (upper and lower) to the outside. Same goes for spar doublers when the spars are straight - glue them so that they oppose each other.
You might check out Hog Bipe build threads too as the Hog and the Bipe share quite a bit.
01-27-2012, 11:40 PM
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RE: Sig Astro Hog - 1st Build
I have 2 of these on the shelf on partially done.. I am looking forward to you build. I flew one of these years ago that belonged to a friend it had a 72 four stroke on it. It was a great flier.
Derrick
Derrick
01-28-2012, 06:07 AM
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RE: Sig Astro Hog - 1st Build
A tip that will make wing mounting easier:
When building the fuselage, drill the 1/4" holes through former F2 before gluing in place. The locations are marked with dimples, so it's easier and more accurate than drilling after the fuselage is complete as stated in the instuction manual (Page 19, Step 9 (b). I would suggest drilling the 1/4" holes in F2 after drilling 3/16" holes in the firewall for the engine mounts. A drill press is best for both jobs if possible.
DaveB
When building the fuselage, drill the 1/4" holes through former F2 before gluing in place. The locations are marked with dimples, so it's easier and more accurate than drilling after the fuselage is complete as stated in the instuction manual (Page 19, Step 9 (b). I would suggest drilling the 1/4" holes in F2 after drilling 3/16" holes in the firewall for the engine mounts. A drill press is best for both jobs if possible.
DaveB
01-28-2012, 07:55 AM
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RE: Sig Astro Hog - 1st Build
Yup, Seamus, that's what I did. The bottom spar bows up at the ends, and the upper bows down at the ends, so they cancel each other out.
Dave, that's one of the notes I made in my manual after reading some AH build threads. I think I got it from yours, in fact. [8D] Thanks for the tip...twice!
Do you guys think I'll be able to correct the slight twist when I skin the wing? Or are there additional measures I should take to straighten it?
~Ron
02-01-2012, 03:00 PM
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RE: Sig Astro Hog - 1st Build
Haven't been back in the shop since last week cuz I was down with a nasty cold over the weekend, and work's been crazy, but I should be able to make some progress this weekend, so stay tuned!
In the meantime, I'm trying to make a decision about which power plant to use, so I could use some advice. I'd like to go either gas or electric. The few planes I have are electric, so I'm fine going that way on this one, though I do plan to move into gas engines at some point, and if I can find a good match for this plane I might as well do so now. I'd rather avoid glow engines altogether, mostly due to the fuel expense and mess, and with more gas engines hitting the market all the time I see no reason to bother with them.
So...gas or electric?
For the electric option, Sig recommends the HiMax Combo 60 for the Astro Hog, but it seems a little like overkill for my purposes. I don't need fire-breathing performance out of this model, so I could probably get away with the Combo 46 shown on the same page as the 60. In either case, though, I'm looking at 2 x 5000 mAh 4S lipos, which is 2 - 2.5 lbs. of batteries alone. The Combo 46 kit sells for $200, and each set of batteries will run about $100 - $120, so the electric option ain't exactly thrifty, particularly when I start adding extra battery sets.
If I go with a gas engine I'm not sure what size I should go with. Again, I don't need it to rip, but there don't seem to be a lot of gas engines available with less than 20cc displacement. Will 20cc be too much for this plane, or for a novice pilot? If so, would an inexpensive 15cc job like this one be an acceptable option?
What do you guys think?
02-02-2012, 05:26 AM
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RE: Sig Astro Hog - 1st Build
IMO, No on the gas engine.
A Hog deserves a 4 stroke, I have a Saito 82 in mine.
Dave pointed out a good tip also. My Hog is over 4 years
old now.
Enjoy the build,
Bob
02-02-2012, 01:07 PM
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RE: Sig Astro Hog - 1st Build
Made a (very) little progress last night. I glued in the W1A and W1B pieces, shown in the first picture. I installed the wing LE after truing up the ends of all the ribs with some light sanding so that they were flat and even, and I installed the top TE sheeting. The last thing I did before knocking off was to build the laminated wingtip bows. They're constructed of lite ply sandwiched between die-cut balsa pieces. I went ahead and built them for both sides to save some gluing time later, and I clamped them between my workbench top and a piece of 3/4" plywood, separating everything with sheets of wax paper.
I've been doing more research on gas engines, and the Saito FG-14B looks like it might be a good option. It's a bit pricey, but the lower operating costs should offset the initial investment somewhat. Plus, I do like the idea of using a 4-stroke as Bob suggested, so this may be a winner.
Seamus, the cowl on Bob's Hog is standard for the kit. It's part of the fuse and is filled out with balsa blocks that you then carve and sand to shape.
Seamus, the cowl on Bob's Hog is standard for the kit. It's part of the fuse and is filled out with balsa blocks that you then carve and sand to shape.
I should be able to get back out into the shop for a bit this evening, so I may have another update tomorrow. Thanks for following along!
02-02-2012, 04:40 PM
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RE: Sig Astro Hog - 1st Build
ORIGINAL: SeamusG
Hey dign - I'm not familiar with the Astro Hog - is your cowl treatment standard SIG approach or your own personal touch?
Hey dign - I'm not familiar with the Astro Hog - is your cowl treatment standard SIG approach or your own personal touch?
By the manual, mostly.
Bob
02-02-2012, 04:43 PM
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RE: Sig Astro Hog - 1st Build
ORIGINAL: Thatsakitbuilt
Dignlivn
What size prop are you using for you astrohog with the satio 82?
Thanks
Cal
Dignlivn
What size prop are you using for you astrohog with the satio 82?
Thanks
Cal
It's a 13x6
,
Bob
02-03-2012, 06:05 AM
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RE: Sig Astro Hog - 1st Build
Last night I un-clamped the wingtip bow laminations, and they turned out great...nice and flat (pic 1)! I cleaned up the edges of the left one, squared up the gluing surfaces, and glued it in place. I then glued in the last rib (pic 2). While that was drying I cut out and cleaned up the LE filler blocks that will go between the 1st and 2nd ribs, and glued the maple anchor blocks onto the grooved LG blocks (pic 3).
One thing I have a question about is the small filler block shown in pic 4 (from the manual) that's supposed to go on top of the wingtip bow, against the 2nd to last rib. It's on the plans as well, but there are no instructions for it in the manual. I assume if I just make it the size and shape shown on the plans I'll be fine, but would be nice to know for sure.
I should have quite a bit of time to spend in the shop this weekend, so I hope to have several updates forthcoming. Thanks for reading, gents!
One thing I have a question about is the small filler block shown in pic 4 (from the manual) that's supposed to go on top of the wingtip bow, against the 2nd to last rib. It's on the plans as well, but there are no instructions for it in the manual. I assume if I just make it the size and shape shown on the plans I'll be fine, but would be nice to know for sure.
I should have quite a bit of time to spend in the shop this weekend, so I hope to have several updates forthcoming. Thanks for reading, gents!
02-03-2012, 06:16 AM
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RE: Sig Astro Hog - 1st Build
The Horizon site says it has power characteristics similar to the FG-72, which should be fine for my purposes.
I am really enjoying the build so far, and I don't mind the carving and sanding. I just hope that when I actually have to "shape" something I don't monkey it up too badly. ;-)
I am really enjoying the build so far, and I don't mind the carving and sanding. I just hope that when I actually have to "shape" something I don't monkey it up too badly. ;-)
02-03-2012, 06:39 AM
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RE: Sig Astro Hog - 1st Build
Thanks, Dign! I'll have to hunt around for a piece of scrap that's big enough, or I may have to laminate 2 thin pieces to make a thicker piece. Since this is my first build the only scrap I have is what's left over from the little bit of construction I've done on this model. LOL
02-03-2012, 05:28 PM
#19
RE: Sig Astro Hog - 1st Build
Wombat, I don't want to throw you off on your build, but the old version of this design had MAJOR dihedral, and most of the people were taking half of the angle out at the center rib angle. I don't know if that has changed? but with the plane originally designed for stability in the early years, it had the dihedral to HELP with flying. It does alter the aileron effectiveness, and inverted flight quality. I just thought I would mention it as it used to be pretty common knowledge, but now less people build, and know about it..
its a great flyer either way, but some don't like it being real V'd looking from the front..
hope I haven't confused you... enjoy the build !
its a great flyer either way, but some don't like it being real V'd looking from the front..
hope I haven't confused you... enjoy the build !
02-05-2012, 12:04 PM
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RE: Sig Astro Hog - 1st Build
ORIGINAL: foodstick
Wombat, I don't want to throw you off on your build, but the old version of this design had MAJOR dihedral, and most of the people were taking half of the angle out at the center rib angle. I don't know if that has changed? but with the plane originally designed for stability in the early years, it had the dihedral to HELP with flying. It does alter the aileron effectiveness, and inverted flight quality. I just thought I would mention it as it used to be pretty common knowledge, but now less people build, and know about it..
its a great flyer either way, but some don't like it being real V'd looking from the front..
hope I haven't confused you... enjoy the build !
Wombat, I don't want to throw you off on your build, but the old version of this design had MAJOR dihedral, and most of the people were taking half of the angle out at the center rib angle. I don't know if that has changed? but with the plane originally designed for stability in the early years, it had the dihedral to HELP with flying. It does alter the aileron effectiveness, and inverted flight quality. I just thought I would mention it as it used to be pretty common knowledge, but now less people build, and know about it..
its a great flyer either way, but some don't like it being real V'd looking from the front..
hope I haven't confused you... enjoy the build !
02-05-2012, 12:09 PM
#21
RE: Sig Astro Hog - 1st Build
As long as you are happy with it is all that matters.
its actually a plane I haven't built yet.. the biplane version sure looks tempting also...
its actually a plane I haven't built yet.. the biplane version sure looks tempting also...
02-05-2012, 12:10 PM
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RE: Sig Astro Hog - 1st Build
ORIGINAL: Rubbernecker
Go with the PT-19. It is an easy modification. Here is mine. Enya 80. Great flyer. Make sure you bend the LG legs foward, she likes to nose over.
John
Go with the PT-19. It is an easy modification. Here is mine. Enya 80. Great flyer. Make sure you bend the LG legs foward, she likes to nose over.
John
02-05-2012, 12:45 PM
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RE: Sig Astro Hog - 1st Build
As I'd hoped, I've been able to get out into the shop and make quite a bit of progress this weekend.
I started Friday evening by removing the left wing panel from my building board, flipping it over, and installing the bottom TE sheeting (pic 1). After dinner I made the forward wingtip braces and submerged them in a pan of water to soak while I carved and sanded the LE filler block between the first 2 ribs (pic 2), and sanded the LE edges to match the rib profile. By then the wingtip braces were nice and flexible, so I glued the root ends of both to the end of the corresponding spar with medium CA, and to the outer rib with thin CA. I gave that a couple of minutes to set, then applied wood glue to the angled ends of the braces, and bent and clamped them to the wingtip bow. I left it all alone for a couple of hours before removing the clamps (pic 3). I also built up the filler block on the wingtip bow from 2 pieces of scrap and glued and clamped them in place (pic 4).
Then came the real learning experience of the evening...gluing on the top LE sheeting. After spreading wood glue over all the surfaces to which the sheeting would be glued, I clamped the rear edge to the spar, usuing scrap pieces of balsa under the clamps to even out the clamping pressure and prevent the clamps from marring the sheeting. I then bent the sheeting toward the LE...and it didn't reach. I verified that I was using the correct piece of sheeting (which I was), and started looking at the pictures in the manual, and at the plans. Then it dawned on me that the sheeting was only supposed to cover 1/2 the spar...d'oh! I was thankful I'd used wood glue, as it was easy to reposition the sheeting and re-clamp it. NOW, the sheeting reached the LE...but the fun was just beginning.
The manual says to apply the sheeting dry, which is probably fine in most cases, but I think I chose the stiffest piece of balsa I had for this particular application. It fought me every step of the way as I tried to use T-pins to secure the sheeting to the LE. I couldn't get it tight enough to the LE using the pins, so I finally gave up and used thin CA to glue the sheeting to the LE in sections, holding each section tight to the LE until the CA set and using pins at each rib as extra insurance (pic 5). It wasn't until after the whole ordeal was done that I noticed the big roll of wide blue tape sitting on the bench behind the wing panel. LOL
And with that, I went to bed.
I started Friday evening by removing the left wing panel from my building board, flipping it over, and installing the bottom TE sheeting (pic 1). After dinner I made the forward wingtip braces and submerged them in a pan of water to soak while I carved and sanded the LE filler block between the first 2 ribs (pic 2), and sanded the LE edges to match the rib profile. By then the wingtip braces were nice and flexible, so I glued the root ends of both to the end of the corresponding spar with medium CA, and to the outer rib with thin CA. I gave that a couple of minutes to set, then applied wood glue to the angled ends of the braces, and bent and clamped them to the wingtip bow. I left it all alone for a couple of hours before removing the clamps (pic 3). I also built up the filler block on the wingtip bow from 2 pieces of scrap and glued and clamped them in place (pic 4).
Then came the real learning experience of the evening...gluing on the top LE sheeting. After spreading wood glue over all the surfaces to which the sheeting would be glued, I clamped the rear edge to the spar, usuing scrap pieces of balsa under the clamps to even out the clamping pressure and prevent the clamps from marring the sheeting. I then bent the sheeting toward the LE...and it didn't reach. I verified that I was using the correct piece of sheeting (which I was), and started looking at the pictures in the manual, and at the plans. Then it dawned on me that the sheeting was only supposed to cover 1/2 the spar...d'oh! I was thankful I'd used wood glue, as it was easy to reposition the sheeting and re-clamp it. NOW, the sheeting reached the LE...but the fun was just beginning.
The manual says to apply the sheeting dry, which is probably fine in most cases, but I think I chose the stiffest piece of balsa I had for this particular application. It fought me every step of the way as I tried to use T-pins to secure the sheeting to the LE. I couldn't get it tight enough to the LE using the pins, so I finally gave up and used thin CA to glue the sheeting to the LE in sections, holding each section tight to the LE until the CA set and using pins at each rib as extra insurance (pic 5). It wasn't until after the whole ordeal was done that I noticed the big roll of wide blue tape sitting on the bench behind the wing panel. LOL
And with that, I went to bed.
02-05-2012, 01:37 PM
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RE: Sig Astro Hog - 1st Build
Saturday morning's activities went much more smoothly than those on Friday evening. :-)
I started by trimming the wingtip end of the upper LE sheeting close to the wingtip profile, then I glued on the bottom LE sheeting. This time, I positioned it properly and used wide masking tape to bend the sheeting to the LE and secure it to dry (pic 1). It worked out MUCH better than using pins. LOL
While the wing sheeting was drying I cleaned up my building board and set it up to start building the right wing panel, taping down the plans and covering them with plastic. Construction proceeded pretty much exactly as with the left panel, except that this time when I glued in the top spar I used more of the vertical press fixtures I got from Paul to clamp the whole thing down straight (pic 2). The fixtures worked out awesome, and I gotta give Paul some props on how well they're constructed, and how easy they are to use.
While the right wing panel was drying I returned to work on the left panel. I wet down the sheeting at the tips and applied wood glue to the wingtip supports, LE, and wingtip bow. I used spring clamps to clamp the sheeting to the wingtip supports, then started clamping the edges to the wingtip bow. The first 2 clamps held with no problems, but the 3rd one stayed on for about 5 seconds before sliding off the sloped wet balsa and flying across the room at considerable velocity. LOL. I added small pieces of paper towel to provide friction for the clamps, and pinned the remaining part of the sheeting to the LE (pic 3). I wasn't able to apply glue to the last rib, so when the glue dries I'll apply thin CA to the joint between the rib and sheeting.
Construction continued on the right wing with the center rib, wingtip bow, TE filler block, LE, and upper TE sheeting (not necessarily in that order). Again, I used the vertical presses to lightly clamp the sheeting in place to dry (pic 4). Finally, I glued the TE in place on the left wing panel, using masking tape to clamp it while the glue dries (pic 5).
Thanks again for reading along, gents. If the Superbowl sucks I may get into the shop this evening, but if not I'll definitely be out there in the evenings this week. Cheers!
I started by trimming the wingtip end of the upper LE sheeting close to the wingtip profile, then I glued on the bottom LE sheeting. This time, I positioned it properly and used wide masking tape to bend the sheeting to the LE and secure it to dry (pic 1). It worked out MUCH better than using pins. LOL
While the wing sheeting was drying I cleaned up my building board and set it up to start building the right wing panel, taping down the plans and covering them with plastic. Construction proceeded pretty much exactly as with the left panel, except that this time when I glued in the top spar I used more of the vertical press fixtures I got from Paul to clamp the whole thing down straight (pic 2). The fixtures worked out awesome, and I gotta give Paul some props on how well they're constructed, and how easy they are to use.
While the right wing panel was drying I returned to work on the left panel. I wet down the sheeting at the tips and applied wood glue to the wingtip supports, LE, and wingtip bow. I used spring clamps to clamp the sheeting to the wingtip supports, then started clamping the edges to the wingtip bow. The first 2 clamps held with no problems, but the 3rd one stayed on for about 5 seconds before sliding off the sloped wet balsa and flying across the room at considerable velocity. LOL. I added small pieces of paper towel to provide friction for the clamps, and pinned the remaining part of the sheeting to the LE (pic 3). I wasn't able to apply glue to the last rib, so when the glue dries I'll apply thin CA to the joint between the rib and sheeting.
Construction continued on the right wing with the center rib, wingtip bow, TE filler block, LE, and upper TE sheeting (not necessarily in that order). Again, I used the vertical presses to lightly clamp the sheeting in place to dry (pic 4). Finally, I glued the TE in place on the left wing panel, using masking tape to clamp it while the glue dries (pic 5).
Thanks again for reading along, gents. If the Superbowl sucks I may get into the shop this evening, but if not I'll definitely be out there in the evenings this week. Cheers!