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Building Tips and technical articles. => Building techniques => Topic started by: Mike Haverly on April 09, 2013, 11:51:54 AM
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I was sitting in my shop last week contemplating on what kind of trouble I could cause for myself. Before I got distracted and built my electric profile, I built a wing for my next PA model. I took it off the shelf and wondered how hard it would be to turn it into a take apart model. Easy answer, too much trouble. Soooo.... Here goes!
My plan was to make as much as I could as opposed to buying, not because I'm cheap but because I know how and I have the tools to do it. I've been in manufacturing all my life and it just seems natural.
I started out with the take apart hardware like the ones Tom Morris sells. I know, there are different products available, but I've used this before and seemed to work fine.
The next step is to dig out my fuselage jig and get going.
I must be nuts!! ???
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Looks good...
Please, post more pics as you move ahead??
Marcus
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Individual rib templates, not stack cut? Do you feel this gives you better ribs, or is it just habit, or what?
How does the Tom Morris stuff actually fasten together? I don't think I've seen these things being assembled or disassembled. Looking closely I don't see any threaded fasteners.
So, is it going to be take-apart 'lectric?
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Tim, this isn't a straight wing so all of the ribs are different. I've had these templates for awhile and have used them for a few different models. Each one of the tubes you see have a 4-40 fastener holding them together. Pictures later will explain better. I'm pretty sure this system came from Europe many years ago. I've seen them used many times on Paul's Impacts. The Sultan I flew last year was done this way.
Off course it's 'lectric! I don't use slimers much anymore, one reason you got my Tower .40.
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I'll stick with "slimers" for classic and possibly Super 70s, but any new PA plane will probably be electric. It's fun.
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Tim, this isn't a straight wing so all of the ribs are different.
Yes, I know. By "stack cut" I meant bolting a stack of balsa blanks between different sized templates, then whittling and sanding the stack smooth. You end up with a bunch of ribs that are all perfectly matched but tapered too much. Then you build your wing, spend about ten minutes with a sanding board, and have ribs that are perfectly matched and are tapered nice, too.
I've seen it recommended in magazines, and I've done it several times myself since anything that I cut by hand needs the session with the sanding board anyway -- I'm just wondering how well you found the "many individual templates" method to work.
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I got the fuselage loaded into the jig upside down and basic assembly done. The bellcrank and take apart hardware are not secured yet and that will be next. Tommorrow I should be able to transfer everything to the wing jig and and start lining things up.
For what it's worth, I have made several rib sets by "stacking". If I didn't already have accurate templates for what I'm doing that would be my third choice. First choice is laser cut ribs and there is no kit for what I'm doing.
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Very cool, Mike. Did you say where you got the take apart hardware?
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Very cool, Mike. Did you say where you got the take apart hardware?
I'll bet he found them next to his lathe one morning. Knowing Mike.
I can't wait to see how the wing sections mate up to the spars -- are they just going to get epoxied together?
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Tim is correct Randy, the take apart hardware showed next to my lathe then went to the mill. I'm still working on things and will post some more pictures later today.
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Made a little more progress. For those that haven't seen the hardware, here is what comes with it when you get it from Tom Morris. The other two pictures are of a little fixture I made for finding the centerline of the ribs. The centerline is necessary for the wing jig.
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So here is where things sit tonight. I'm about ready to sheet the leading edge but the material that I have is badly tapered and is unusable. The LG blocks are installed, most of the shear webs are in place and the rear hardware mounts are in. I'll put the rest of the trailing edge on and start to work on the control surfaces while I'm waiting for my material to arrive from National Balsa.
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Mike
Amazing job.
Thanks for the pictures.
Marcus
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Wing jig design looks familiar. Looks great, Mike.
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I finally got back to work on this. There is new interest in these parts for an airline legal take apart for a trip to Poland.
Both flaps are now completed. The inboard flap weighs 32 grams and the outboard at 28 grams. The stab and elevator are ready to be mounted to the fuselage. They weigh 80 grams as they sit without hinges. The next thing I will do is to attach the wings to the fuselage and mount the take apart hardware for the stabilizer.
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Hello Mike,
Very nice work. Makes me want to give a take-apart a try. Cool idea with the controls remaining in place when the stab is removed.
Regards,
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Thanks for the pics of a good looking build. Sure explains a lot of questions on the take apart system.
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Kinda slow going, other things going on, but I got the stab mount on an lined up with the wing. The mount itself is a piece of .125 light ply with a piece of 1/16 ply under the two front mounts. All three hole locations have a 3/8 maple dowel hard point to take the load. All three screws are 2-56 socket head screws. While it is still in the jig with the incidence meter I'll install the motor mount.
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Kinda slow going, other things going on...
And I thank you for going on with those other things.
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Construction on the tail assembly is complete. I decided to attach the elevator horn to the stab. Doing it the other way there may have been a problem fitting into the already constructed travel box. To check into an airlines the box must be no larger than 62 inches, the total of length plus width plus height. The driving dimension is the length of the fuselage. I'll start working on the front end now starting with the motor mount. Incidentally, all of the mating surfaces of removable pieces are faced with 1/64 plywood. It is a lot easier to make clean separations.
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Very nice...
Marcus
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That's pretty slick Mike!!
Derek
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Nice work, Mikey. I like the in place controls on the stab a lot. I may steal that idea when I build my next take apart. I have a somewhat different idea for the wing take apart system, but I will also make my own.
Very slick. I look forward to seeing it live --- if I ever get to fly again.
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I guess you don't have any planes worth flying anymore?? Get out of the shop and go fly before you have to retrain yourself from the dizzy's. And I should talk. Am getting ready for the Ringmaster weekend. H^^
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I started going about business on other parts when I realized I hadn't built the tail wheel mount. This has been shown before by others, but here it is again. I think this is similar to the way it is done on the Yatsenko models. I used 1/16 carbon fiber in the middle, but I think plywood could used instead.
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Unbelievable craftsmanship Mike! Thanks for showing the detail work.
Jason
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That looks great!
I like how you made the bottom of the fuse, at the back, angled. That will give you so much more room when connecting the pushrod to the elevator horn. VERY NICE!!
Thanks for the pics.
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That looks great!
I like how you made the bottom of the fuse, at the back, angled. That will give you so much more room when connecting the pushrod to the elevator horn. VERY NICE!!
Thanks for the pics.
X2!!!!
Marcus
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That looks great!
I like how you made the bottom of the fuse, at the back, angled. That will give you so much more room when connecting the pushrod to the elevator horn. VERY NICE!!
Thanks for the pics.
Thanks Doug. On last year's model the back is square with a removable rudder. I had to make the rudder removable to fit in the box (that wasn't made yet). I had to make access hatches under the stab which made the whole back end weak. It was plenty strong before the rudder removal. This is much better. One thing I didn't show was the stab construction. I moulded the leading edge per your build post. That also works slick. I didn't save much weight, but it is very accurate and quick.
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.... One thing I didn't show was the stab construction. I moulded the leading edge per your build post. That also works slick. I didn't save much weight, but it is very accurate and quick.
That's great!!! I am glad it worked out for you. That is always good to hear.
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Mike does nice work.
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I used 1/16 carbon fiber in the middle, but I think plywood could used instead.
You used plywood on the side pieces, but I think carbon fiber could be used instead.
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You used plywood on the side pieces, but I think carbon fiber could be used instead.
You are right, of course. But I chose not to! ;)
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I've been asked a few times about the front end/motor mount construction on my Sultan. This is the same except for being a top loader, I've made modifications for that. The motor is front mounted to a 1/4 plywood mount. It is very strong and with the 1/64 ply doublers plenty rigid. Air is taken in around the spinner as well as the inlet on the bottom. The battery mount and floor have been omitted for clarity, the ESC will be covered by it. Hope this all makes sense.
Edit: The PDF may also clear some things up.
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Mike,
These are great photos, thanks for taking the time to provide them, plus explanation text.
Your woodwork is excellent. Kudos!
Near future, possibly, I'll be looking forward to something electric, Your build and info will come in handy for sure.
Thanks again.
Charles
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Mike, do I see bushings through the bolt holes in the 1/4" ply motor mount bulkhead? Have you had crushing problems there?
Jack
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No Jack, I have not had crushing problems, and I'm not going to either! I have done the same thing on maple mounts for IC engines. Yes, I used 1/4 aluminum to take the load. There is a carbon fiber plate that goes over the whole thing.
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Mike,
That's a great build you have there with your model.
I have a pusher design on my board and I like to ask a few questions of you.
Hope you don't mind.
Wing area of that model and the motor brand and size you will use?
Your 1/64 doubler. Is that a ring around your 1/4 firewall mount?
Thanks,
Charles
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Charles,
The fuselage sides are 3/32. There is a 1/64 doubler on the inside that goes to the middle of the wing. Original plans were for 1/8 sides and 1/32 doubler. There is no vibration with electric power so I chose to lighten things up. It is still plenty strong.
The motor is front mounted and the motor mount is fastened in the very front of the fuselage. There is a 3/8 balsa nose ring with 1/32 plywood on the front. The outside diameter of the ring is 2.0 inches and a 1.75 dia. spinner. The spinner is recessed by about 1/8 inch allowing air around it and straight into the motor.
The wing area is almost 690 sq. in.
I don't see how any of this has anything to do with "pusher".
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Charles,
The fuselage sides are 3/32. There is a 1/64 doubler on the inside that goes to the middle of the wing. Original plans were for 1/8 sides and 1/32 doubler. There is no vibration with electric power so I chose to lighten things up. It is still plenty strong.
The motor is front mounted and the motor mount is fastened in the very front of the fuselage. There is a 3/8 balsa nose ring with 1/32 plywood on the front. The outside diameter of the ring is 2.0 inches and a 1.75 dia. spinner. The spinner is recessed by about 1/8 inch allowing air around it and straight into the motor.
The wing area is almost 690 sq. in.
I don't see how any of this has anything to do with "pusher".
Mike,
There's all kinds of similarities. ;D
My real interest was the size of the motor and brand?
That information would be a delight!
Charles
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It will have an Eflite Power 32, Ice Lite 75 ESC, Hubin FM-9R timer and 5S 2700 batteries.
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It will have an Eflite Power 32, Ice Lite 75 ESC, Hubin FM-9R timer and 5S 2700 batteries.
I'll be using the same set up soon...
Nice work!!!
Marcus
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It will have an Eflite Power 32, Ice Lite 75 ESC, Hubin FM-9R timer and 5S 2700 batteries.
That should work...... Nice work.
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Mike,
How is your model comming along?
Your choice was the E-Flite 32.
Any reason as to why you chose that particular motor?
Charles
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The motor and ESC choice was easy, I have three of them and have been using them for three years. The airplane is in finishing stages.