gugie
FUN FLYER
Posts: 154
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Post by gugie on May 19, 2013 23:00:10 GMT -4
Gang, been working with Cliff on the new 737 so thought I would post some pictures of what we've been working on. First here's a picture of Cliff working on the main landing gear. We were trying to see if there was going to be enough clearance between the nacelles and the ground when the landing gear is compressed. This gives you a good feel for the size of this jet. (It's big) Some of the decals have been applied. We still have some minor work to do on the main gear such as shorting the wheel axles and slotting one end to accept the "C"clip. First challenge was fixing the nose gear. Cliff through some creative efforts was able to figure out how to mount the nose gear to operate in a scale manner. I’ll get some pictures once I’m back at the shop With the main gear we realized that with the main gear compressed the engine nacelles were pretty close to the ground so we added a brass tubing shim to the lower wheel strut which limited the amount of compression the lower strut saw which allowed the nacelles to stay at a safe height when the main gear is compressed. We also realized that the wing wooden gear mounts were not level so when the retract units were screwed to the mounts the main wheel struts were at an angle which did not let the two wheels sit flush on the ground. To fix this problem I mixed some epoxy and thickened it with West Systems filler, laid a layer on the wood mounts in the wing and then aligned the wheels with an aluminum rod and used toothpicks to align up the mounting holes with the holes in the wing mount. Update: Forgot to mention that I put tape on the landing gear to keep the landing gear from being epoxied to the wing. Next I'll post how we set up the flaps with hidden linkages. In a later post I'll show the work we did with getting the fan units mounted inside the nacelle and the nacelle mounted to the wing.
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Post by Chris Reibert on May 19, 2013 23:02:14 GMT -4
Sick!!!!
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Post by Dr. Evil on May 20, 2013 8:51:30 GMT -4
One word.......WOW. Looking forward to more!
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Post by doc121 on May 20, 2013 11:31:07 GMT -4
AWESOME
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chaos666
PARK FLYER
RCA TEAM REP
About to build the Chaos 700 V2 prototype! :)
Posts: 59
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Post by chaos666 on May 20, 2013 13:50:46 GMT -4
That's a badass airplane WOW, can that be taken off from a grass runway?
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gugie
FUN FLYER
Posts: 154
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Post by gugie on May 21, 2013 2:37:22 GMT -4
The flaps One of our challenges was to figure out how to hook the flaps up to the servo. Since the flaps are of the drop type (Fowler type) activating them with a control rod to a regular control horn wasn’t going to work. One of my goals was to figure out a way to hide as much of the linkage as possible. The first step was to plan it out. I drew out some possible scenarios taking as many measurements as I could and then picked the one I thought was the most simplistic and functional. Here's what the end result looked like: (The 737 has split flaps) This is the top view and you can just make out the control rods Here's the bottom view with the outer wing panel off: With this scenario the hardest part was figuring out how I was going to attach the linkage to the flap. With a little bit of thinking I came up with the idea of making a pivot pin mount out of wood. This wood mount is drilled and then epoxied into the flap Here you can see wood block in the flap and what the custom linkage looked like and where the attachment points would be. (the rod actually connects in about ¼” from the edge as this is in alignment with the servo arm: To get this mount into the flap I had to make a small cutout in one edge of the flap. (These edges are hidden when the wing is assembled. Once this was cut out I then took a small hardwood wing spar and trimmed this to the shape of the leading edge of the flap. Some measurements were taken to figure out where the servo pushrod was going to exit the trailing edge of the wing and attach to this flap. Then a small notch was cut into this mount using the dimension above and a hole drilled through to accept a pivot pin. The pivot pin is nothing more than a Dubro threaded coupler. I soldered a small rod inside and slotted it to accept a small screwdriver. The left edge of this wood mount has an over sized hole drilled about 3/4 of a way to the notch in which a nut is epoxied into it. This gives the threaded coupler (Pivot pin) something to screw into and keeps it from backing out. A push rod was made from brass tubing flattened on one end and drilled to accept the pivot pin. The other end has a piece of a metal threaded rod soldered into the end which has a servo clevis attached to it. This is needed to make fine adjustments to the flap position. The bend on the left end was needed to allow the flap to drop further. Once the wood mount in epoxied into place in the flap the top leading edge of the flap was trimmed at the same location as the notch in the wood mount. Then a notch was made in the trailing edge of the wing at the same location. This is where the flap linkage exited the wing and entered the flap and then connected to the pivot pin. You only need to slot the flap at the leading edge and at the trailing edge of the wing where the linkage comes out at. If you do it right when the flap is retracted you can't see the slots or the linkage Next post will be mounting the fans in the nacelles and attaching the nacelles to the wing
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Post by Dr. Evil on May 21, 2013 8:48:41 GMT -4
Very very nice work there buddy....clever idea I must say. Good job, looking forward to the rest of the build....keep it coming.
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gugie
FUN FLYER
Posts: 154
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Post by gugie on May 23, 2013 1:40:08 GMT -4
Mounting the fan units to the nacelle. Bear with me guys as this particular posting is rather long. I spent almost 4 weeks trying to get it right. What you get in the kit for mounting the fans to the nacelles are two plywood formers. In the picture below you can see where these formers go. You can also see that there really isn’t any intutitive way to see how the fan housing attaches to these. These two formers slide into the extended top piece of the nacelle. My first thought was how was I going to attach the fan housing to these formers. So here is my first attempt at strengthen these formers but I still wasn’t sure how to attach the fans to these. You can see that one side tapers before the other by the small gap on the center block. So after several weeks of trying this and trying that I came upon the idea of using a single 1/8” 5 ply Birch plywood former/rib. (If I do this again I might go a little thicker but the 5 ply seems strong enough) This former/rib would be attach to the wing via the carbon fiber wing spar and also be the mount for the fan units. Here’s a picture of what it looks like after I cut it out. You can also see where I slotted the top edge of the nacelle that sits under the wing. Here you can see where I made the initial slits in this part of the nacelle. Notice how that slot is going to be offset. This is needed because the fan mounts need to sit centered in the nacelle and if the slot was centered the fans would be offset a little. With the nacelle slotted this is what the piece looks like when fitted inside the nacelle Here you can see the rib/former mounted on the wing with a hole made for the carbon tube wing spar. The hole was tricky because it needed to align perfectly with the tube in the center wing. To do this I found a 12” brass tube the same diameter as the inner carbon tube and notched one end to look like below. This was inserted into the carbon tube in the center wing which extended about 5” past the inside edge. Then by taping the rib/former to the edge I was able to grab the brass tube from the opening in the inner wing and by rotating it back and forth while pushing out I was able to cut the hole in this rib/former at the right angle and the exact location. You can see where this brass tube is just starting to cut through the rib/former Once I got the brass about half way through the plywood I took it out and finished cutting it. I figured out where the fan housing attached to this rib/former and drilled a hole that lined up with one of the fan mounting brackets. Since I wanted to make sure this portion was strong I epoxied a ½” x 3/8” hardwood strip to the opposite side of where the fan would mount and also epoxied in a blind nut. The end that butts up against the curved portion of the nacelle where the wing leading edge sits needed to get tapered but if I would have cut this piece a little shorter I wouldn’t have needed to have done this. Here you can see how the pieces fit together Here’s a better picture showing the nacelle assembly sandwiched between the inner and outer wing pieces. Here you can see what it looks like mounted Next posting I'll show how I attach the two wings together.
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gugie
FUN FLYER
Posts: 154
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Post by gugie on May 24, 2013 21:27:00 GMT -4
Next is figuring out how to attach the outer wing to the inner wing. While the carbon tubes were a snug fit I ended up sanding the inner one slightly so that the inner tube slide in smoothly without binding. Since these outer wings need to be removable I had to figure out a way to attach these so that they would not come apart but yet would be easily removable. So here’s how I did it. In one of my frequent trips to our local hardware store (I go there so often I’m on a first name basis with them) I found a table leg mounting bolt that was a screw on one side and threaded on the other. So with this I bought a dowel that I had to cut down to fit snugly inside the inner carbon spar and then I drilled a hole (Slightly smaller than the screw portion of this screw/bolt) centered in this dowel. Then with this bolt/screw I screwed one end in till the bolt threads were flush with the top of the dowel. I next taped the top part of the carbon tube so when I glued in this dowel none of the glue got on the outside of the tube, otherwise it will not easily slide inside the outer carbon wing spar. This dowel is then epoxied into the inner carbon wing spar. I used a clothespin to hold the dowel in position while the epoxy dried. This inner carbon wing spar is epoxied into the outer wing panel. Here you can see the bolt sticking out of the other side of the inner carbon tube. With this tube spar slid inside the tube in the inner wing you can see that the inner tube is inset by about ½” from the edge of the outer tube. Next I slid a plastic cap that I again found at the hardware store this fit perfectly over this tube. (All you really need is a washer bigger than the diameter of the outer tube but the cap looked better) Then I slid a metal washer on top of this and then I have a wing nut which had a plastic ring so it acts similar to a locking nut which will keep the wing nut from backing out. Wa-la there you go! You have a way to securely attach the outer wing and fan/nacelle to the inner wing and by simply unscrewing the wing nut you can disassemble everything very quickly.. In going over this post I'm realizing that there maybe some details I left out so there maybe some of you puzzled with some of these steps. If there are any questions please feel free to ask.
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Post by doc121 on May 25, 2013 17:33:26 GMT -4
Very nice work gugie. I'm loving the wing connecting mod. That's COOL!
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gugie
FUN FLYER
Posts: 154
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Post by gugie on May 28, 2013 11:07:22 GMT -4
Guys, thanks for all the compliments! I thought I was going to get a lot done over the weekend and holiday but needless to say the family had other plans for me. I need to work on the inlet and outlet ducting. There has been a lot of research done on ducting size and I'm getting close to figuring out what I need. Luckily ducting is not going to be as hard as it is on the jets where the fan units are buried inside a fuselage! Whew!!!! Will post more of the build as progress is made. Thanks again for the comments! They are much appreciated...
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Post by Chris Reibert on May 30, 2013 7:32:18 GMT -4
Hey Gugie will it 3D... Just kidding. Looking good! Can't wait to see the flight video Need a keychain cam inside the cockpit.
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Post by sgmason on May 30, 2013 9:11:17 GMT -4
Chris, that is a sizable plane, you could fit a lot more than a keychain cam in there. Heck I think my Polariod would fit in the cockpit no problem. The added weight of a bigger camera would cut down on the wet noodle video like I see on YT all the time.
I am trying to figure out how to mount my camera on one of my planes without modifying either the camera or the planes.
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gugie
FUN FLYER
Posts: 154
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Post by gugie on Jun 4, 2013 0:55:55 GMT -4
Chris, First you and your wife are closing in fast on your new arrival!!! Our son and his wife are expecting their second baby June 15 and we're just about as excited as they are!!!! As for the video cam in the 737... You have definitely been talking to Cliff. We were going to put several in the Tiger but we ran out of time. We're planning on putting in some for the .90 size Apache that I'm building. Cliff also talked about putting some in the Bell 429. I think it's called cam crazy..... Will look nice when and if we can make it happen. But first we want to get the 737 flying and still have a lot to do to it. We got together this last weekend and were able to get the wings on the body to check the gear height and get the second motor put together and wired to the speed controller. We also tried to get the outer right wing panel's aileron and flap installed but still have a little bit more to do before this is done. We got the pivot block made and just have to make the pushrod. We also realized that the front sat too high so need to raise the nose gear inside the fuselage about 3/8" to get the plane at the right angle. I asked Cliff for a different nose gear so need to pick that up before moving forward with the inside gear mounting bulkhead. Will try and get some pictures once I get the nose gear in.
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gugie
FUN FLYER
Posts: 154
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Post by gugie on Jun 7, 2013 20:53:02 GMT -4
This will give you a feel for the size of this plane. I'm having to rework the nosegear mounting as we have to drop it by about 1/2" as the plane did not sit right with batteries placed and everything.
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