Scalpel Build
#1
Thread Starter
Scalpel Build
The newest thing on my table. It's called the Scalpel. Drawn by our man, skaliwag. A 1/2A speedster with a strong resemblence to the old Ace Simple 400 kit. It actually uses the tapered Ace foam wings with the remaining build consisting of wood. I've had this sitting around for some time just waiting for the opportunity and motivation to start tinkering with it.
I've never worked with Ace wings before so I'm sort of guessing as I move along. I had to trim the center sections at an angle so that the trailing edges would line up straight. I glued the wood trailing edges on with Sig-Bond. I'm still pondering what to use as hinge glue as thin CA would probably eat the foam away. Won't have to worry about that for a while yet.
The fuse build seems pretty straight forward but it will be pretty cramped in there with a 1oz tank, radio, servos, battery, etc.
I plan to power this thing with the Mangusta DR .049 rear rotary induction engine pictured. If the engine doesn't perform up to par, I'll use a TD .049. It will be 3 channel rud/elev/ail. I have no intention of installing a throttle. Not looking to win a pylon race. Just want a fast sport flyer.
That's all I have to show for now. I'll update as everything progresses. Feel free to chime in, advise, or criticize.
I've never worked with Ace wings before so I'm sort of guessing as I move along. I had to trim the center sections at an angle so that the trailing edges would line up straight. I glued the wood trailing edges on with Sig-Bond. I'm still pondering what to use as hinge glue as thin CA would probably eat the foam away. Won't have to worry about that for a while yet.
The fuse build seems pretty straight forward but it will be pretty cramped in there with a 1oz tank, radio, servos, battery, etc.
I plan to power this thing with the Mangusta DR .049 rear rotary induction engine pictured. If the engine doesn't perform up to par, I'll use a TD .049. It will be 3 channel rud/elev/ail. I have no intention of installing a throttle. Not looking to win a pylon race. Just want a fast sport flyer.
That's all I have to show for now. I'll update as everything progresses. Feel free to chime in, advise, or criticize.
#2
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RE: Scalpel Build
I like it, you will be showing a video of the first flight right?(Iforgot to say plz)
I have 2 ace foamy`s on their way, 1 constant chord and 1 tapered chord(for my son`s ace pocket rocket build.)
I will just usesomehobico 5 min. epoxy for the foam joint, hinges and trailing edgeson ours.
Normally, ace foam wings had a 1/8"(i think 1/8) spar running down the cg, on the underside for sure, but I thinkon top too,andbalsa trailing edge, bothwere pretty high grade balsa if I remember correctly.
I have only built 3 of these ace foam wing kits; and was years ago, but I would have to do some digging to get real specific. But I can see mu pocket rocket hanging from the cieling, def. a spar on the wing underside. (just trying to help) For the wing joint and spar, you may want a slower cure time than 5 min.epoxy btw I also never built an ace foam wing with ailerons, notyet lol
I have 2 ace foamy`s on their way, 1 constant chord and 1 tapered chord(for my son`s ace pocket rocket build.)
I will just usesomehobico 5 min. epoxy for the foam joint, hinges and trailing edgeson ours.
Normally, ace foam wings had a 1/8"(i think 1/8) spar running down the cg, on the underside for sure, but I thinkon top too,andbalsa trailing edge, bothwere pretty high grade balsa if I remember correctly.
I have only built 3 of these ace foam wing kits; and was years ago, but I would have to do some digging to get real specific. But I can see mu pocket rocket hanging from the cieling, def. a spar on the wing underside. (just trying to help) For the wing joint and spar, you may want a slower cure time than 5 min.epoxy btw I also never built an ace foam wing with ailerons, notyet lol
#8
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RE: Scalpel Build
Today I trimmed and sanded the trailing edges a bit. Then I drilled some holes in the root ends, filled them with epoxy, and joined the two halves together. I decided to make the spars much like skaliwag and used the carbon fiber tow thread. I experimented with the bottom side first. The channel was made by cutting a piece of sanding belt the same width as a popsicle stick, and securing them to a sanding block with tape. I just pinned a piece of wood to the wing to act as a guide. Not beautiful, but effective. I brushed Z-Poxy Finishing Resin into the channel, put the c/f thread in and pulled it tight as I brushed more resin over it. It was getting pretty cool outside so I brought the finished item into the house to help it cure tonight. I'll have to flip it over and repeat the process on the top side.
#9
Thread Starter
RE: Scalpel Build
BTW, though the drawings on the bench show a V-tail option, this model will be built with a traditional vertical tail. I'll leave that bit of complexity for another guy to try.
#12
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RE: Scalpel Build
It's easy to forget how small our 1/2A models are compared with what most folks are flying. Here's my Scalpel and .60 sized P-51 fuses posing together. They are sooo different, yet very similar.
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RE: Scalpel Build
Oh geez, yeah, I forget there are planes larger than 1/2A on a regular basis; I only fly/build 1/2A since 1990,and they keep getting smaller as I go. Shoot, my 049`s are mostly dust collectors at this point.(saving them for when my eyesight gets too bad for the small stuff)
I recently was over at my Dads house and out of the blue he came up with the ide he wants to get the old Royal Air 40T out and get her up in the air sometime when we have a chance. Now you have to understand this plane has been "in my old hanger" at his house, and hasn`t been touched since `96 after a prior 5 year stretch there.
Then he started talking about wantint to put together (after he retires) my 1/4scale (anniversary edition I think)piper cub that hasnt seen fresh air, box hidden in my old "stash" of plane stuff since about `88 or so.
I reminded him how huge it is and how much space we would need to use to build this hulk of a plane, and I would rather sell it.
I was floored by all this from him lol
I recently was over at my Dads house and out of the blue he came up with the ide he wants to get the old Royal Air 40T out and get her up in the air sometime when we have a chance. Now you have to understand this plane has been "in my old hanger" at his house, and hasn`t been touched since `96 after a prior 5 year stretch there.
Then he started talking about wantint to put together (after he retires) my 1/4scale (anniversary edition I think)piper cub that hasnt seen fresh air, box hidden in my old "stash" of plane stuff since about `88 or so.
I reminded him how huge it is and how much space we would need to use to build this hulk of a plane, and I would rather sell it.
I was floored by all this from him lol
#14
Thread Starter
RE: Scalpel Build
Got the firewall and wing hold-down ply plate epoxied in place. I made the firewall as small as I could to fit the large engine mounting flange. This firewall placement allows plenty of room for a 1oz tank and plumbing. The nose moment is now longer than the drawing. This will probably disappoint some folks here but I trimmed off the remaining cowl cheeks flush with the firewall. Skaliwag drew this up with a nice rounded cowling that fairs down to a spinner, mostly enclosing the engine in the process. This is a sleek look but this build not only serves as a test-bed for Steve's design but also as a living display of sorts for the Mangusta DR .049 engine. I just didn't want to cover up those neatly machined bits. Hopefully she'll fly great, Steve will make the kit available to the masses, and everyone can carve cowlings according to their heart's desire, or not. The wing will be held in place by the 1/8" dowels up front and a nylon bolt in the rear.
This is getting done in very short sessions due to my overtime schedule at work. Cheers.
This is getting done in very short sessions due to my overtime schedule at work. Cheers.
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RE: Scalpel Build
I`m keeping an eye on this one, may be a great pland for a few engines I have sitting around, taking turns sitting around,and waiting to be flown lol
I have this norvel 061r/c. G-mark 061, and a couple throttled teedees that are getting impatient lol
Looks good so far TeeBee, esp. that engine, I wouldn`t want to cover it up either (except to protect it from my flying skills/lack thereof )
I have this norvel 061r/c. G-mark 061, and a couple throttled teedees that are getting impatient lol
Looks good so far TeeBee, esp. that engine, I wouldn`t want to cover it up either (except to protect it from my flying skills/lack thereof )
#18
Thread Starter
RE: Scalpel Build
My table has lost it's "flatness" over the years. I placed a solid wood door(Don't ask.) on the table to get it flat again. I currently have a Great Planes balsa building board screwed down on top of that with a few shims to get it true. That's not such a big issue with this particular model but really helps with built up wings.
#20
Thread Starter
RE: Scalpel Build
I finished my graveyard shifts last night and decided to stay up today to rotate back to a normal nighttime sleep schedule the rest of the week. I usually go to the flying field on this morning of the rotation but it's too windy. This allowed me to get some more work done to the Scalpel this morning before the world woke up and got busy. The servo hole was cut using a Dremel router-type bit in a flex cable attachment. It made easy work of cutting the foam out. I laid out the trailing edge pieces and cut them to separate the ailerons from the center trailing edge. Next I scuffed up the aileron torque rod tubes, cleaned them with alcohol, marked and centered them on the trailing edge, and epoxied them in place.
Notice how the bend that will fit the aileron is too far outboard. I meant to make a closer bend before attaching these pieces. Not sure how I'm gonna rectify it now that they're glued on. Grrr. These things happen when I build planes while sleepy.
Also note that I got the top "spar" carbon tow thread epoxied in yesterday. I placed it a little further back than the bottom spar. It seems to have added a lot of strength to the wing.
Sorry the pics are a bit fuzzy. It's very humid this morning and my cam phone doesn't like it.
Notice how the bend that will fit the aileron is too far outboard. I meant to make a closer bend before attaching these pieces. Not sure how I'm gonna rectify it now that they're glued on. Grrr. These things happen when I build planes while sleepy.
Also note that I got the top "spar" carbon tow thread epoxied in yesterday. I placed it a little further back than the bottom spar. It seems to have added a lot of strength to the wing.
Sorry the pics are a bit fuzzy. It's very humid this morning and my cam phone doesn't like it.
#21
RE: Scalpel Build
ORIGINAL: Tee Bee
Notice how the bend that will fit the aileron is too far outboard. I meant to make a closer bend before attaching these pieces. Not sure how I'm gonna rectify it now that they're glued on. Grrr. These things happen when I build planes while sleepy.
Notice how the bend that will fit the aileron is too far outboard. I meant to make a closer bend before attaching these pieces. Not sure how I'm gonna rectify it now that they're glued on. Grrr. These things happen when I build planes while sleepy.
I don't see that as a problem at all - your aileron torque rods aren't going to twist and having the bend a little further out moves the twisting component on the aileron away from the aileron tip. Place your hinge just outboard of the bend and I think it will be just fine. Unless you use a continuous tape or covering film hinge, the majority of the aileron is unsupported anyway.
I don't have a flex cable for my Dremel, but I do have the router attachment that attaches to the end. Like you, I've found that I can cut all manner of shapes and depths in foam using the router bit.
The build is looking good - I like all the pics.
andrew
#22
Thread Starter
RE: Scalpel Build
Note how the torque rods can't move fully due to hitting the trailing edge and the wing hold down ply. I notched everything to allow them to swivel without binding. This is normal build stuff that most of you already know but I'm hoping that it may help someone who is new to the hobby. Instead of making fancy wingtips, I simply traced some onto 1/8" scrap lite-ply. I will cut them out with a scroll saw, epoxy them in place, and sand flush with the wing.
It's gonna be crowded in this fuselage. I'm getting a bit concerned about everything fitting, balancing, and not interfering. Got some new servos on order for the rudder and elevator. I'll do some trial fitting before sheeting the fuselage so I can adjust everything as needed. HS-55s would fit nicely in there but I'm going with some a bit larger(See the 1/2A Servos Revisited thread). I'm holding off on choosing a receiver until the clearance issue is sorted. Would like to use a Spektrum 2.4 but if space is an issue, I may substitute a Berg4L 72MHz unit with an old-school antenna.
It's gonna be crowded in this fuselage. I'm getting a bit concerned about everything fitting, balancing, and not interfering. Got some new servos on order for the rudder and elevator. I'll do some trial fitting before sheeting the fuselage so I can adjust everything as needed. HS-55s would fit nicely in there but I'm going with some a bit larger(See the 1/2A Servos Revisited thread). I'm holding off on choosing a receiver until the clearance issue is sorted. Would like to use a Spektrum 2.4 but if space is an issue, I may substitute a Berg4L 72MHz unit with an old-school antenna.
#23
Thread Starter
RE: Scalpel Build
My work schedule has been impeding progress on the Scalpel. I am $75 poorer though after ordering some new battery packs and micro on/off switches from Radical RC today. That should count for something.
#24
Thread Starter
RE: Scalpel Build
This morning I cut out the lite ply wingtips and epoxied them in place. After a bit of measuring to make sure the wing was centered and square with the fuselage, I glued the wing dowels into the wing with just enough 30 min epoxy to hold them. I'll come back later and add more epoxy to fill in the gaps in the slightly oversized dowel holes that I drilled into the foam.
#25
Thread Starter
RE: Scalpel Build
Got the wing trailing edges epoxied on.
I had to hollow out some channels in the tapered balsa pieces with a razor blade to allow them to fit over the torque rods. I also cut some notches in them to allow the torque rods to swivel. To prevent fuel/oil creep from getting to the bare wood inside the torque rod holes, I applied epoxy finishing resin to the area inside the trailing edges where the torque rods are outboard the brass tubes. I ironed on some covering patches to the wings under the torque rods. This will protect the wing and make this area easier to cover later. Then installed the wing on the fuse with some wax paper in between and set everything into place to cure. Had to be careful not to get epoxy on the torque rod wires which could bind them from moving.
I'm planning to use some small traditional CA hinges on the ailerons. I was concerned with which glue to use since thin CA is required to wick into the hinges properly but didn't want it to wick past the wood and melt the foam wing. Most foam-safe CAs aren't thin enough to flow well into CA hinges. I contacted Bob Smith Industries with my issue and they recommeded their Super Gold Thin foam-safe CA for this use. Nice folks. I'll be ordering a bottle of it.
I had to hollow out some channels in the tapered balsa pieces with a razor blade to allow them to fit over the torque rods. I also cut some notches in them to allow the torque rods to swivel. To prevent fuel/oil creep from getting to the bare wood inside the torque rod holes, I applied epoxy finishing resin to the area inside the trailing edges where the torque rods are outboard the brass tubes. I ironed on some covering patches to the wings under the torque rods. This will protect the wing and make this area easier to cover later. Then installed the wing on the fuse with some wax paper in between and set everything into place to cure. Had to be careful not to get epoxy on the torque rod wires which could bind them from moving.
I'm planning to use some small traditional CA hinges on the ailerons. I was concerned with which glue to use since thin CA is required to wick into the hinges properly but didn't want it to wick past the wood and melt the foam wing. Most foam-safe CAs aren't thin enough to flow well into CA hinges. I contacted Bob Smith Industries with my issue and they recommeded their Super Gold Thin foam-safe CA for this use. Nice folks. I'll be ordering a bottle of it.