SIG Stratus (#RC4) - the long slow plans build
03-13-2015, 08:48 PM
#51
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Hey, Dave, It's a lot of fun seeing this beauty come together by your efforts. I can relate to your enjoyment of building from plans. Those who buy airplanes to assemble are missing so much enjoyment. Transforming sticks and sheets if balsa and plywood with a some other ingredients to make a "living" object is a great experience. Those sheets and sticks you are cutting and shaping will soon be pulled around the sky at 90 mph by a snarling hunk of metal and you will have been in control of the whole event from start to finish. Keep up the good work!
Man, I love this hobby!
Man, I love this hobby!
03-14-2015, 01:39 PM
#52
Thread Starter
Well, once again the plan changes - I can put the OS46AX back in the box for another plane "someday". Went to a swap meet this morning and found a OS61SF just begging me to put her in the nose of the Stratus, so I bought it for $50. Seemed like a fair price to me. She's got new bearings front & back and I got to see her run with a 12x8 APC prop - does just fine. Best guess is that I can now also build a vertical launch ramp and just send it up like the space shuttle (well, maybe not quite vertical). I'm thinking right now to put a 11x6 or 11x7 3-blade prop, which should also work just fine. Thinking about ground clearance.
Also gonna need a motor mount for that 61. Tower, here I come ... AGAIN.
Mar 16th - once again in the changes department, and this is my "take no chances" style of caution coming out, the plans call for 3/16" firewall which simply doesn't seem like enough structure to hold that monster .61sf - so I'm going with a 5/16" firewall instead, plus it's pinned to the sides and fuel tank area doubler that is now 3/16" ply instead of 5/16" balsa, along with the 3/4" triangle side bracing. Yeah, it's a bit more weight but I don't think the .61 is going to mind even a little bit.
Also gonna need a motor mount for that 61. Tower, here I come ... AGAIN.
Mar 16th - once again in the changes department, and this is my "take no chances" style of caution coming out, the plans call for 3/16" firewall which simply doesn't seem like enough structure to hold that monster .61sf - so I'm going with a 5/16" firewall instead, plus it's pinned to the sides and fuel tank area doubler that is now 3/16" ply instead of 5/16" balsa, along with the 3/4" triangle side bracing. Yeah, it's a bit more weight but I don't think the .61 is going to mind even a little bit.
Last edited by skylark-flier; 03-16-2015 at 01:17 PM. Reason: Added the last paragraph
03-17-2015, 10:45 AM
#53
Thread Starter
The fuselage is "one"!
The first pic shows the basic fuse siding, 2nd shows the inside framing and 1/16" ply scabs over where I joined balsa to extend the fuse, and 3rd shows the firewall epoxied in place with rubber bands holding it. The ply sheet in place at the wing LE point is the same dimensions as the firewall but it's just sitting there as a placeholder right now. That point shows on the plans as just being framed with 1/4 x 1/4 balsa but I'm cutting out a bulkhead that'll serve as the front attachment point for the wing (going with bolts vs rubber bands). At the wing TE the plans also show just a 1/4 x 1/4 balsa frame - it'll also be a ply bulkhead instead.
Definitely getting there. Still have a bit to do today, then it's the waiting game for my Tower shipment that has my engine mount, fuel tank and a couple other goodies. Also, tomorrow I'm heading to my LHS (yeah, the one that's 65 miles away) for some more 1/4" balsa so I can start laminating up for the upper and lower blocks around the fuel tank, and the nose cowl. He doesn't carry actual blocks but he does have the 4" wide boards, which are just fine by me.
Hokay, got a question. In my limited experience with building front ends, I'm seeing the engine held to the mount by nuts & bolts. If I build the nose section and attach it to the rest of the fuse I have no access to the "bottom" side of the mount to do the nut & bolt thing. The engine is mounted on her side, just for reference. The original was definitely built as all one piece but I can't see how to be able to attach & remove the engine. How's it done guys?
The first pic shows the basic fuse siding, 2nd shows the inside framing and 1/16" ply scabs over where I joined balsa to extend the fuse, and 3rd shows the firewall epoxied in place with rubber bands holding it. The ply sheet in place at the wing LE point is the same dimensions as the firewall but it's just sitting there as a placeholder right now. That point shows on the plans as just being framed with 1/4 x 1/4 balsa but I'm cutting out a bulkhead that'll serve as the front attachment point for the wing (going with bolts vs rubber bands). At the wing TE the plans also show just a 1/4 x 1/4 balsa frame - it'll also be a ply bulkhead instead.
Definitely getting there. Still have a bit to do today, then it's the waiting game for my Tower shipment that has my engine mount, fuel tank and a couple other goodies. Also, tomorrow I'm heading to my LHS (yeah, the one that's 65 miles away) for some more 1/4" balsa so I can start laminating up for the upper and lower blocks around the fuel tank, and the nose cowl. He doesn't carry actual blocks but he does have the 4" wide boards, which are just fine by me.
Hokay, got a question. In my limited experience with building front ends, I'm seeing the engine held to the mount by nuts & bolts. If I build the nose section and attach it to the rest of the fuse I have no access to the "bottom" side of the mount to do the nut & bolt thing. The engine is mounted on her side, just for reference. The original was definitely built as all one piece but I can't see how to be able to attach & remove the engine. How's it done guys?
03-17-2015, 12:05 PM
#55
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Dave,
I'm not sure what type of material your mounts from Tower are but I generally tap the mounts if it is aluminum, T-nuts if its wood, and nuts and bolts if its the nylon type. Since you will have no access to the bottom side of the mounts I would use aluminum and tap them if it isn't already done. My 2 cents
I'm not sure what type of material your mounts from Tower are but I generally tap the mounts if it is aluminum, T-nuts if its wood, and nuts and bolts if its the nylon type. Since you will have no access to the bottom side of the mounts I would use aluminum and tap them if it isn't already done. My 2 cents
03-17-2015, 01:07 PM
#58
03-17-2015, 01:08 PM
#59
03-17-2015, 04:09 PM
#60
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G-10 is immensely strong, the size horns you are making a single layer is fine. On my 100cc gassers I've mounted a ball-link between to horns and then run a 4-40 through the ball-link to tie them together. Any wood you mount them to in the plane will be the weak spot.
03-18-2015, 05:27 AM
#61
I haven't seen this design so I'm a little in the dark. Sight unseen I think I would attempt to make part of the nose removable like GP did in some of their Warbird kits. Dave's problem deserves a lot more thought and a lot more information than I have.
Mike
Mike
03-18-2015, 07:06 AM
#62
Some sort of cowl is all I can think of, outside of using a tapped motor mount.
03-18-2015, 08:38 AM
#63
Thread Starter
Sorry I missed the question when you wrote it, I guess I was focused on my Sr.
G-10 is immensely strong, the size horns you are making a single layer is fine. On my 100cc gassers I've mounted a ball-link between to horns and then run a 4-40 through the ball-link to tie them together. Any wood you mount them to in the plane will be the weak spot.
G-10 is immensely strong, the size horns you are making a single layer is fine. On my 100cc gassers I've mounted a ball-link between to horns and then run a 4-40 through the ball-link to tie them together. Any wood you mount them to in the plane will be the weak spot.
The engine mount I'm using comes from Tower, it's glass-filled nylon and comes with "self-tapping" screws. I ordered 2 mounts just in case I mess one up.
In the "y'gotta-do-what-y'gotta-do" world, I couldn't resist:
03-18-2015, 04:03 PM
#65
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Great progress, Dave. It's going to be a beauty. The motor mount can be as simple as a one piece glass filled nylon mount that is drilled for the hole dimension of the engine to be used. What you have should work fine as long as it fits within the confines of the firewall. Tap the holes for 6-32 socket head bolts. Install the motor mount on the firewall then install the engine and build the cowling around it with balsa. Fair the cowling around a plywood spinner ring made according to the spinner to be used.
I have never had an engine come loose using this method. No lock nuts are necessary. It's simple and easy.
Did you intend to epoxy the fuel tank in place as it seems to sound in your text above? The tank should be free to "float" in some foam or confined loosely in the tank area, otherwise the engine vibration might cause the fuel to foam and screw up the fuel mixture going to the engine. Also, the tank should be accessible to be able to service it at some point.
Keep on keepin' on. It's looking good!
I have never had an engine come loose using this method. No lock nuts are necessary. It's simple and easy.
Did you intend to epoxy the fuel tank in place as it seems to sound in your text above? The tank should be free to "float" in some foam or confined loosely in the tank area, otherwise the engine vibration might cause the fuel to foam and screw up the fuel mixture going to the engine. Also, the tank should be accessible to be able to service it at some point.
Keep on keepin' on. It's looking good!
03-18-2015, 07:36 PM
#66
Thread Starter
Thanks Mike - that's good news. Yeah, I'm planning to do the drill & tap bit. As with so many things on this plane, that'll be a first for me. Just asking, how'd you keep the nylok nuts on when/if you dismounted the engine? Epoxy? CA?
Sherwood, I epoxied the bulkhead in place, along with the bulkhead behind the wing (also not on plans but I'm more comfy with one there). Had to cut a HUGE hole (actually left little more than 3/8" wood on both sides and 1/4" on top) in the front one to slide the tank in through, and the rear is little more than a plywood framework - 1/2" sides all around. The fuel tank measures 2.5x2.5x5", cutout is 1/8" larger on all sides. Tank will actually stick through the rear by about 1/2" or so. Got tons of foam for it too, no problem there. Marked the firewall today for the vertical center line. I'm planning on mounting it just a hair to the left so I can cant it to the right a bit and still be at center with the prop shaft as it goes through the front plate (yeah, ply for that front plate too). 6-32 socket head bolts & blind nuts is exactly what I've got on the table for mounting through the firewall.
Got tired of seeing the fuse sides just hanging there - braced it all down and cut the cross-beams, fuse is all together now, including the tail cone - - and wonder of wonders, it's absolutely straight!! Tomorrow I'm hoping to get the control rods built and mount the servos, more or less in prep of covering the fuse rear. Also need to drill a hole in the tail cone for the antenna tube to go through. This bird, as are all my birds, will be on 72 MHz.
Landing gear struts came out rather decent, and they match. Gotta admit, that surprised me a bit. Bought 2 of the 5/32 x 36" steel rods with the idea of messing up at least one of the struts. Now I've got 1.3 of the rods left just sitting around (another plane in the future maybe, who knows?).
Sherwood, I epoxied the bulkhead in place, along with the bulkhead behind the wing (also not on plans but I'm more comfy with one there). Had to cut a HUGE hole (actually left little more than 3/8" wood on both sides and 1/4" on top) in the front one to slide the tank in through, and the rear is little more than a plywood framework - 1/2" sides all around. The fuel tank measures 2.5x2.5x5", cutout is 1/8" larger on all sides. Tank will actually stick through the rear by about 1/2" or so. Got tons of foam for it too, no problem there. Marked the firewall today for the vertical center line. I'm planning on mounting it just a hair to the left so I can cant it to the right a bit and still be at center with the prop shaft as it goes through the front plate (yeah, ply for that front plate too). 6-32 socket head bolts & blind nuts is exactly what I've got on the table for mounting through the firewall.
Got tired of seeing the fuse sides just hanging there - braced it all down and cut the cross-beams, fuse is all together now, including the tail cone - - and wonder of wonders, it's absolutely straight!! Tomorrow I'm hoping to get the control rods built and mount the servos, more or less in prep of covering the fuse rear. Also need to drill a hole in the tail cone for the antenna tube to go through. This bird, as are all my birds, will be on 72 MHz.
Landing gear struts came out rather decent, and they match. Gotta admit, that surprised me a bit. Bought 2 of the 5/32 x 36" steel rods with the idea of messing up at least one of the struts. Now I've got 1.3 of the rods left just sitting around (another plane in the future maybe, who knows?).
03-19-2015, 08:59 AM
#68
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The build is looking great! If you are going to drill & tap the motor mount, nylok nuts are not needed. If you need more "peace of mind" perhaps a drop of low strength (blue) threadlocker on each screw on final assembly would work? Even just a bit of silicone sealant on the thread will keep the screw from loosening.
Last edited by DBD1; 03-19-2015 at 09:02 AM.
03-19-2015, 08:03 PM
#70
Thread Starter
Hehe, yeah - me! Always have been, probably always will be a worry wart. Actually, that's not a half-bad idea - the blue goop - and I'll probably go with it.
Brought her up from the shop so I could clean up a bit - getting a lotta wood/paper/tape/crud all over the place down there. Set her up in the livingroom just for giggles - she takes up most of the center of the room. BIG plane, for me. Took a couple pics, they show those 2 bulkheads and how little is left of either of them once the center holes were cut out.
Wanted to start today on framing up the nose section but I can't really do a whole lot on it until I've got the engine mounted and can see what my clearances are. Tomorrow I'll start on the servo mounts and top decking. Anybody know a reason I couldn't use a mini-servo for the throttle?
Brought her up from the shop so I could clean up a bit - getting a lotta wood/paper/tape/crud all over the place down there. Set her up in the livingroom just for giggles - she takes up most of the center of the room. BIG plane, for me. Took a couple pics, they show those 2 bulkheads and how little is left of either of them once the center holes were cut out.
Wanted to start today on framing up the nose section but I can't really do a whole lot on it until I've got the engine mounted and can see what my clearances are. Tomorrow I'll start on the servo mounts and top decking. Anybody know a reason I couldn't use a mini-servo for the throttle?
03-20-2015, 02:45 AM
#71
I would be careful when applying chemicals to a composite motor mount. Threadlocker or silicone may attack the composite materials.
If you want to glue the engine bolts, I suggest canopy glue. I don't think it will attack the composites.
If you want to glue the engine bolts, I suggest canopy glue. I don't think it will attack the composites.
Last edited by TomCrump; 03-20-2015 at 02:48 AM.
03-20-2015, 05:14 AM
#72
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Worrying about engine bolts backing out of the motor mounts is unnecessary. The tapped motor mount will, by itself, hold the screws in place. If worrying persists, install lock washers over the flat washers on the bolts, which is a good idea anyway. I've used this method for years with no problems.
03-20-2015, 08:57 PM
#73
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I tapped a glass-filled nylon mount years ago with no problems. I didn't use any "thread locker" but I did remove the muffler and put a Allen wrench on the bolts at least once during the flying season for peace of mind. Takes only a few minutes!
03-20-2015, 09:01 PM
#74
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Hehe, yeah - me! Always have been, probably always will be a worry wart. Actually, that's not a half-bad idea - the blue goop - and I'll probably go with it.
Brought her up from the shop so I could clean up a bit - getting a lotta wood/paper/tape/crud all over the place down there. Set her up in the livingroom just for giggles - she takes up most of the center of the room. BIG plane, for me. Took a couple pics, they show those 2 bulkheads and how little is left of either of them once the center holes were cut out.
Wanted to start today on framing up the nose section but I can't really do a whole lot on it until I've got the engine mounted and can see what my clearances are. Tomorrow I'll start on the servo mounts and top decking. Anybody know a reason I couldn't use a mini-servo for the throttle?
Brought her up from the shop so I could clean up a bit - getting a lotta wood/paper/tape/crud all over the place down there. Set her up in the livingroom just for giggles - she takes up most of the center of the room. BIG plane, for me. Took a couple pics, they show those 2 bulkheads and how little is left of either of them once the center holes were cut out.
Wanted to start today on framing up the nose section but I can't really do a whole lot on it until I've got the engine mounted and can see what my clearances are. Tomorrow I'll start on the servo mounts and top decking. Anybody know a reason I couldn't use a mini-servo for the throttle?
I love the pics of it framed up! Tail is unique looking to be sure and the fuse looks solidly built. Great job! Someone said "I love this hobby" in an earlier post, I couldn't agree more, fun stuff!
03-21-2015, 09:16 PM
#75
Thread Starter
Geez, hadn't thought about that Tom. Good thinking. Yeah, a couple mechanic friends of mine are saying the same thing - just go with tapping and be sure they're tight once in awhile.
Sherwood, you've got it - lock washers ALWAYS work.
Alan, that fuse is designed like a tank chassis. I installed the turtle deck today and she suddenly looks like a 1955 Dodge - solid as a rock. NOTHING flexes anymore, not even a little bit. Also had to laminate up some 1/4" & 1/8" balsa to make my 3/8" cowl pieces - seems like 3/8" balsa simply isn't available around here. By the time I'm done sanding it all down it'll be a whole lot thinner than that but with the curves in the nose the extra thickness is necessary for starters. Also got into laminating some more 1/4" balsa into 1/2" x 1/2" sticks for the inside corner blocks on the cowl, then cut them into triangle shape. That took all of 10 minutes.
Tomorrow (Sunday), assuming I don't just chuck it all and take a couple planes out for the day, I'm intending to install the servo mounts, servos & control rods (which was actually supposed to be done today). Then I can put the bottom on her and start sanding all that down too.
Also, got a whole slew of jumbo shrimp & pineapple chunks in the fridge that'll go on the barby, but that's later in the day.
Sherwood, you've got it - lock washers ALWAYS work.
Alan, that fuse is designed like a tank chassis. I installed the turtle deck today and she suddenly looks like a 1955 Dodge - solid as a rock. NOTHING flexes anymore, not even a little bit. Also had to laminate up some 1/4" & 1/8" balsa to make my 3/8" cowl pieces - seems like 3/8" balsa simply isn't available around here. By the time I'm done sanding it all down it'll be a whole lot thinner than that but with the curves in the nose the extra thickness is necessary for starters. Also got into laminating some more 1/4" balsa into 1/2" x 1/2" sticks for the inside corner blocks on the cowl, then cut them into triangle shape. That took all of 10 minutes.
Tomorrow (Sunday), assuming I don't just chuck it all and take a couple planes out for the day, I'm intending to install the servo mounts, servos & control rods (which was actually supposed to be done today). Then I can put the bottom on her and start sanding all that down too.
Also, got a whole slew of jumbo shrimp & pineapple chunks in the fridge that'll go on the barby, but that's later in the day.
