Friday, June 30, 2017

Mitchell U-2 Flying Wing R/C Project Progress and Setbacks

This has been quite a week for me while working on this project.  There has been some nice progress with the build and a setback or two so I thought I best get this out to everyone before I forget what I have been dealing with or give up completely on the project.  Not likely in either case I as I would rather work things out and keep moving forward on the plane to complete it.

For the progress this week I have manage to get the wing of the model pretty well prepped for final sanding.  The flaws that I found after cutting the wing have been either sanded out or filled in with the white colored micro-balloon epoxy mixture.  A very light substance that I mixed up for this and for all my fiberglass projects.  I will have to sand the wing one more time and then I will have to figure out if I am going to do any covering over the wing for the glider tests that will follow.
This side view of the fuselage shows the different sections that will have to be 3D printed to build it. At the top of course is the canopy.  Then starting on the left and moving to the first vertical line is the nose of the fuselage and then three more sections ending with the tail section. This was done this way simply because I do not own an industrial sized 3D printer.  I can make some rather large 3D prints such as the canopy in one piece which by the way is 8 1/2 inches long but the entire fuselage put together comes up to 16 1/2 inches long.  Far larger than my 3D printer can handle so this is the plan of action for the 3D printing part of the project.

I also managed to make some really nice 3D printed parts for the project as shown above.  The top piece is the nose of the fuselage.  This I sanded smooth starting with 120 grit then moving on to 600 grit for wet sanding and then another round of 800 grit also wet sanding to give it a very smooth and uniform surface.   Below the nose are the two wing tips for the plane.  These I did not need to be sand at all as the are plenty smooth and will work out perfectly.  The nose of the plane took four hours to 3D print and the two wing tips took an additional three hours total to make.  Not out of the ordinary as 3D printing large parts takes a bunch of time.  The nose is 3 1/2 inches tall and the two wing tips are 3 1/4 inches tall.  

Here is the second section of the fuselage.  I am very please that this part turned out as well as it did as it is one of the key pieces to mounting the wings.  You can see the first portion of the airfoil on the side of the fuselage with a hole going through it.  This hole along with another one in the next section will allow the wing to be attached and removed when I am transporting it.  The wing having a span of 68 inches makes this a necessity.   The wing will have wooden dowels that will match the mounting holes and then be locked together inside of the fuselage. I have a plan for that when the time comes.  This being another large part  being 4.5 inches tall, 4 inches wide, and 5 inches long took 9 hours to 3D print.  Again I sanded it smooth to prep it for final assembly to the rest of the fuselage.

Now on to the setback and recovery of the project so far.  Pictured above is the bubble canopy that will be on the plane.  It was to take five hours to print this large part and be totally black and pretty in the process.  I was not so lucky with this 3D print.  Four hours into the making of this part my 3D printed decided it had enough and stopped printing. Auggah!!!!!!   So now I had a windshield instead of a bubble. What caused the failure was a clogged drive wheel for the extruder.  It happens.  Not that I like it but it happens.  Any easy fix and I am 3D printing once again. 

I shifted gears and last night epoxied and fiberglassed a small piece of Styrofoam to the failed 3D print.  It was a shot in the dark to try and save this part and not have to try and print another that would take an additional five hours to complete. 

With some careful trimming and sanding I was able to resurrect the part and save it from the trash can. With the shape of the canopy pretty well formed already it was only a matter of a few minutes work and I was able to save the part.  I will then fiberglass the exterior completely with a couple of light layers of fiberglass cloth and then sand and smooth everything as I had originally planned.  I think the weight will not be a factor as the foam and glass combined will give me the shape but not add to much more weight to the part. 

I had to tape the parts together to give you a good photo of how the fuselage will look for real if only the front section can be shown so far.   I will fiberglass all of the parts together once everything has been 3D printed.  All except the bubble canopy which I plan to make removable.  This will allow me to open up the fuselage to add or remove weight to it when I want to balance the plane for glider testing.  If that all works out then I will look at making it a full R/C plane with electric power.  I may have to remake the wings at that point to get the controls all set up in the plane but this will be far simpler than having to duplicate the fuselage that by the way will probably take nearly 30 hours of 3D printing to complete.  I will give you the correct number on that aspect of the project when I get that far along.  Hopefully in the coming week.  So for now the project is still moving forward and looking pretty amazing on top of it all. Only time will tell if the project will succeed or not.  Just will have to keep playing with it.  

Monday, June 26, 2017

The Mitchell U-2 R/C Flying Wing Project Has Started!

It's been a little while since I last posted anything so I thought I'd better catch up a bit and let you know what I have been playing with since my last post.  I had been thinking of several different projects over the past few weeks and finally decided to work on one that has been on my mind for some time.  Years ago I built an ultralight aircraft.  It was called a Mitchell U-2 which was a flying wing.  A lot of people at the time asked me if it was a kit.  I told them if a pile of wood, some tubing, wheels and an engine was a kit than that what it was.  Not to mention a ton of fabrication and a lot of luck to even complete the project. But it was a very rewarding project just the same.  

Here are a couple photos of my plane.  It was a massive project and I am proud to say that I built it by myself.    This was quite some time ago when I built this.  (1982-1983 or somewhere around that time).  That brings us to today.  I thought it would be fun to build another plane like the Mitchell only much smaller.  I thought a replica of the Mitchell U-2 would be fun to recreate as an radio controlled electric model.  

As is usually the case with the projects that I build I start by doing some research and designing the project in my computer. This was the only image that I could find online of the Mitchell Wing that was of any use to me.  It is a good drawing to start with so from it I was able to create a 3D model of the R/C plane and begin working out some of the design.

 The image above is what I have come up with for the project of the Mitchell U-2 electric R/C plane.  As I stated earlier the original plane had a 34 foot wingspan.  I wanted the model plane to have a good size which I thought would be simpler to create and also not have to deal with very small parts out on the wing tips.  The plane that I plan to make will be 1/6th scale.  This will reduce the span down to 68 inches.  Still quite a large plane but this will give me lots of room for the radio gear, servo's, electric motor, and battery in the fuselage.  

The servo's for the plane need to be mounted into the outer portion of the wing to be able to activate the rudders at the tips along with the elevons. The elevens are the pieces that extend out past the trailing edge of the wing to have control like an aileron and an elevator on a conventional plane.  Only both functions at the same time. 

This will take some planning for sure as it has been some time since I've done anything with radio controlled planes.  I was able to create the 3D model and from it them start making the templates to create the wings in Styrofoam.  The image above shows the wing in blue and white.  Actually each side of the wing will be built in three sections. A white inner wing, then the blue middle section, and finally another white outer wing.  If you look at the image above you can see three differently shaped sections of the wing.  From these sections I started printing out templates for the various shapes of each wing end. 

Here is what the ribs looked like once I had plotted them out full size.  The top rib (Rib One) is 11 inches long and the smallest rib (Rib Four) is only around 2 1/2 inches long.  This short rib is used at the very tip of the wing. 

I then took the paper templates and transferred them on to 1/8" plywood, cut them out on my band saw and temporarily attached them to 2" thick pieces of Styrofoam.  The wooden pieces were then used as guides for my hotwire table so that I could cut out the inner most sections of the wing for the plane. 

These were a couple of first failed attempts at cutting the Styrofoam with the plywood guides and my hot wire table.  The trick was to start the cut at the same angle as the leading edge and then work my way around to the front of the wing.  I had more than enough scrap 2" Styrofoam sitting around in the shop from other projects so this was a good project to use it on.

After the first couple failed attempts at cutting the foam sections I got the process down to where with careful planning I had achieved near perfection on the shape of the first section of the wing.  As you can see the number one rib and number two rib templates gives the wing a very different look as to compared with a normal straight wing where the rib pattern is all the same across the wing. 

Here all of the wing parts have been shaped using the rib templates for the left side of the wing. Pretty impressive so far considering the wing has a long ways to go yet.

Here again is another shot with all of the major wing parts that I have completed.  At this point I will start sanding any imperfections that I have in each section of the wing and filling in any voids using a micro-balloon and resin mixture.  Then more sanding will be the order of the day to get the wings perfectly shaped the way I want.

I had to slide all of the pieces for the wing together to check and see how close I was to that actual dimensions that I had designed on the computer.  The wing above measures 64" exactly.  This is perfect as there is no fuselage built yet but I do know that it will be 4" wide so this will give me exactly 68" as I had planned. 

One other thing that I had to plan for while cutting out the Styrofoam for the wings was the dihedral that is designed into the wing for stability.  This took some carful planning in the cutting of the blanks for each section of the wing along with correct placement of the wooden rib templates.  From what I can see I think I have this worked out.  Just will have to see once I start test flying it.

The fuselage on the plane I had originally thought I would make out of fiberglass.  But after looking at the assembly in the computer I changed my mind and thought I would try and 3D print it instead.  The fuselage is 16 1/2" inches long, 7" tall and 4" wide at the widest section.   Quite large but I have it laid out in the computer and with some fancy cutting and splicing together of the 3D printed parts I think it is possible.  I'll give it a try anyway.  I printed just the nose section so far and that alone took four hours.  The next section going rearward looks to have to take nine hours+ so it will be a bunch of hours just to make the fuselage.  I'll keep track for sure on this part of the build.

To also work out some of the bugs that I will come across in the design the first plane will only be a glider. This way I can figure out the weight and balance of the plane and then later upgrade it so that the glider will then be radio controlled.  If that all works out then the final version will be a full electric powered motor glider.  So step by step.  I'll post more as I get some if not all of the parts for the fuselage 3D printed and put together.  

Stay tuned for further developments.  

Thursday, June 15, 2017

The "Altara" Concept Blender 3D Car Is Born!

When the dusts settles in my workshop from finishing a project I usually  can be found elsewhere creating something new on my computer using Blender 3D.  This is the case with the creation of a concept car that I originally drew a little over four years ago. At that time it was just a 2D image that was a spark of inspiration and so the idea was born to change it to a 3D model.  

Here are a couple of the completed images of the Altara concept car that I managed to put together over the past couple of weeks.  But before we get into more details on what you see here I want to show you where it all started and then the process of how I got to where it is now.

I liked the shape that I had come up with the time I put this image together but after looking at it again changes were the order of the day to make it just a bit more refined and workable as a 3D model.  The wheels needed to be changed first as what I have here was way to simple of a design.  So it was added to my growing list of what needed to be improved.

Having only a side view of the car to work with I needed to flesh out the rest of the body in Blender 3D to work out the front, rear, and top of the car to my liking.   Even the openings for the wheels needed to be tweaked a bit but at least the body at this point was taking shape.  

 Following cues from my original 2D drawing I started putting in the openings for the windshield and the rear window.  It was a start but everything that I added at this point was just to get an idea of what would actually work and not work in the real world.  I realized early on that I had a long way to go with the model.

Next I cut the openings for the headlights and refined the front hood of the car.  This was not terribly difficult and so progress was being made and I was encouraged that the design was possible at this point. 

Early on I start playing around with lighting of the car to see what I can see when I put the body together.  In the image above you can see the seams for the front hood, canopy and the rear hatch. I also started looking at headlight covers at this point.

At this point I added the tires and some rims to the design.  I kept the body height the same as the original 2D drawing and this was the result of that decision.  Not good to be sure.  The body looks nice and sleek but the tires look too small and unusable in the real world.  The front tires are not believable in the fact that the wheel opening is way to small for the tire to be able to roll much less turn.  More work changes to my list was in order.

At this point I raised the car up to give the wheels more clearance and enlarged the wheel opens to something that looked more proper. The wheel rims were close to what I was looking for but the centers were to small and there was no bolts holding the rims onto the hubs.  More items for my list of changes. 

The next step was getting the wheels and rims more correct looking.  I enlarged the center of the rims and added the nuts for the hubs.  Also I added a disc brake inside of the wheels rather than have it all blacked out by the lighting. On the front of the car I added a grill, running lights, signal lights and headlights. 

This next series of images gives you good views of the car body from the rear.  Taken from the original drawing is of course the body itself, the rear body quarter panel with the top arch and the rear window. 

Here you can see the original placement of the tires and rims. The body again at this point was still in the original placement that matched the original drawing.  In other words it is to low.  That and the fact that the tires are set to far into the body to be believable. 

I moved the wheels outward at this point which worked out very nicely but the wheel openings are to small as I said earlier in the post. 

Finally I have the wheels and opening corrected with the right body height.  But now what stuck out was the rear window.  Way to small!  It would not do.  So that would be the next step. 

I proceeded to make the rear window larger and with this process it cleaned up the entire look of the rear of the car.  

This is a good look at the side of the car before I finished off the wheels with the disc brakes.  I like the rear window and roof line now with the larger rear window.  Much more believable. 

 With the rear of the car I started playing around with taillights and a name plate for the car.  "Altara" I came up with from an old SciFi movie that I remembered so I thought it would be a good name for this sleek looking vehicle.  The rear of the body was recessed for the lights and no tail pipes.  I thought would be good as an electric car. So no tail pipes. 

Lastly I changed the glass in the car to clear instead of gloss black.  This made it look much more like a vehicle instead of just a model of one.  I still can put a lot more detail into the car by finishing out the interior with all the it needs but for now this will do nicely. Enjoy the images. 😀  

Friday, June 9, 2017

The Couch Table Project Is Completed!

It's been a difficult week trying to force myself to work on any projects while I was at home.  Not that the projects I am currently working on have given me any grieve or the fact that I have lost interest in them.  The weather here in the Midwest has finally given me and everyone else just perfect conditions to be outside to enjoy better weather than we've seen over the past couple of months at least.  Bright, warm and sunny have been the words that best describe the weather for the past week.  But even with all of that going on I have managed to put the finishing touches to my couch table project over the past couple of days.  (In between long motorcycle rides of course.)

So with this post I thought I would let everyone get caught up on this project and pass along detailed information about how I put it all together. 

This is a photo of all the wooden parts that were needed to create the little couch table. All of the wood was select pine.  I choose this as it is very inexpensive and the wood is nice and straight without any knots in it.  Also pine is a very easy wood to work with so it was an simple choice to make.  

Starting in the upper right corner is the top of the table which measures 16" x 20".  This had to be pieced together using 1 X 6's and a 1 X 4 and pocket holes to get the dimensions I wanted.  I used my Kreg pocket hole jig to make the mounting holes and assemble the top together.

Next to that are the two cross supports for the table. These are 1 X 4's 20" long.  Below the table top are the two legs of the table.  Again 1 X 4's 25.5" long.  The smaller piece to the right of the legs is a 1 X 2 X 18.5" long piece that already has the pocket holes drilled into the ends of the part.  Lastly are the four tapered pieces that make up the feet and table supports for the project.  Again these parts are 1 X 4's that are 15.25" long.  They are all tapered down to 1 1/2" tall on the ends with a nice radius to finish them off.  These parts also needed pocket holes as shown so that they could be mounted correctly in the assembly.

As I did not have an assistant to help me hold the leg and table support assemblies together while installing the mounting screws for it I created this simple little jig out of scrap wood.  Just a few wood screws to hold it all together did the trick nicely.

Here I have one end of the leg assembly mounted into the jig and ready to be screwed together.  I put the pocket holes on the outside of the assembly so that the screws when installed would not split the end face of the cross member. If the parts were reversed the pocket holes would be on the inside of course and also point the screws in the wrong direction causing problems when assembling the parts together. 

Here is what the leg and table top supports looked like once the parts had been assembled.  The little jig did the trick nicely as installing the pocket hole screws went very smoothly.

Here the table has been completely assembled.  The upper table top support assembly and the leg assemblies have been mounted to the legs of the table.  This was just a matter of squaring things up so the table sat nice and flat on the floor and screwing in four mounting screws at each of the upper and lower positions where the assemblies mated up to the legs of the table.  With the screws for the assembly on the inside of the table the outside legs covered up the pocket holes on the outside of the assembly giving the table a very nice clean look that works very well.  The table top itself was then slid into place on top of the upper supports  and held in place using 1-1/2" metal "L" brackets and wood screws from the underside of the table.  Again this way I could keep everything nice and clean looking on the outside surfaces of the table. 

The last few steps to finish off the table were just a matter of sanding everything nice and smooth and then applying a stain and three or four coats of varnish.  I was not sure about the finish on the project until I had put the first couple of coats of varnish on the table.  Then I stepped back, took a good look and put my seal of approval on the project. 

It will be a nice addition to my living room when I want to sit down and watch TV while eating dinner or playing on my laptop.  Total cost for the little table came to around $30.  A far cry from the $100+ table I had stumbled across last Christmas and it will serve my purposes just as well. 

One last little thing that I need to do with the table while I am writing this is to add some small felt pads to the bottom of it so that I won't scratch up my hardwood floor when I am moving it around on the floor.   So my efforts once again have been worth the time spent to create this little table.