R/C Helicopter Canopy

Okay, this is really something my daughter made. I just bought a Thunder Tiger Mini Titan electric helicopter. It was already assembled, but came with a boring white canopy and lame stickers. This is where my daughter Anna and her Sharpy collection came to the rescue. Check out the awesome results:

BTW, I bought this heli from Discount Hobby Warehouse in San Diego. I used to work for them in college (20 years ago). I flew helis then, but the technology was very different. This is a family owned business. My old boss, the owner, helped me pick out this new heli, then helped me program the radio and the gyro (yes, the gyro has its own computer). He also employs a young man who is very knowledgable about 3D flying who is very helpful.

Mini Katana Repaired

Okay, I didn't build this one. I bought it almost ready to fly from Atlanta Hobby It flies great. It has a 250 Watt power system that puts out 1.5 times more thrust than the airplane weight. The great thing about the Mini Katana is that it flies like a normal airplane. Most 3D capable airplanes are strange in normal flight, but this one is a joy. It does beautiful touch and goes, knife edge, tail slides, etc, but it will hover too. The dry airframe is only about 13 oz.



Why the odd white triangles on the wings? Well, my dumb-thumbs flew her a little too low... I scraped the landing gear off, broke the motor mount, and destroyed the lovely fiberglass cowl. Now she is all better. The worst damage was from the sharp back-ends of the wheel pants poking holes through the wings. I had to do fairly major rib and sheeting reconstruction. Unfortunately, I don't have any transparent red covering, so I patched it with white.

RC Trainer "Cutie"

My youngest daughter and I built this trainer together:


This kit is fully laser cut, and it was a joy to build. It even has laser cut lexan parts, including a little hook that holds the battery hatch down. I got the kit from SR Batteries



Mary picked the nice color scheme. The airplane was designed for a speed 400 brushed motor and gear box. The brushless installation is just so much cleaner. When I was in high school, I built a Lee Renaud designed Q-Tee. It has an internal-combustion .049 engine, and flew great. This one has so much more power, but weighs about the same.



The first flight was in a fair amount of wind, but this plane is not as light as most modern electrics, and frankly, for training in a bit of wind, it is perfect. It flew very nicely. My daughter handles it pretty well. Landings are easy.

Every year, my flying club, the the Torrey Pines Gulls, does a flight demo for Torrey Pines Elementary's Science Discovery Day. We demo to three groups of about 7 kids for 25 minutes each group. The last 10 minutes we line them all up and let them fly a few circles around the sky, under very close supervision. I usually loose a plane this way each year, so I bring cheap foam trainers. This year we had a lot of wind and the foamies were grounded. I decided to let them fly my daughter's plane (I know, stupid). Well, it went perfectly. It was easier for the kids to fly, and it has so much power, I could climb to altitude after each kid's turn really quickly. So, now I know the secret: you have more to loose with a good trainer, but much less chance of actually loosing it. Anyway, the Cutie has only four flights so far, but about 20 pilots!

Brass Strut for 1907 Firestone-Columbus

My father has a very rare 1907 Firestone-Columbus horseless carriage.



He needed to fabricate two roughly 3" tall brass struts to prevent the rear bar that supports the motor mount from bending. We drew a sketch of the part, then I drew it up in TurboCAD Mac.




I 3D printed two copies as patterns for sand casting. He had them cast in red-brass. He still has to machine the top to act as a cradle for the truss rod. I was going to put that feature into the pattern, but my dad pointed out that the patterns wouldn't come out of the sand cleanly if we did. The casting is rougher than the pattern, but preserved some of the fine patterns left from the FDM extrusion, which actually looks kind of cool.


The brass casting is on the left, the ABS pastic pattern is on the right

When Spiders Attack

My daughter built a snap-together Gundam model with nice ball joints for the legs and neck. That made me wonder if I could make useable ball joints on the 3D printer. I modeled one up and pritned it. It worked pretty good. If one works, why not 17? That's the beauty of drawing then printing – copy and paste is a wonderful thing. Thus was born the spider model.




The spider is crawling on my 1:20.3 model of the Carter Brothers Hobart Estates caboose. Maybe I'll post it separatley one day. The poseable legs help make it look like it's crawling. Pretty creepy in person, actually

I modeled the body and joints in TurboCAD Pro on the Mac. I modeled the head and leg segments in CB Model Pro, then imported the STL to TurboCAD and added balls and sockets. The sockets are subtracted from the body solid. I did not bother to actually add the balls and sockets to the imported STL parts, as that crushes TurboCAD. It's no problem though, TurbCAD creates STL files from the superimposed mesh-solid hybrids.



This is the ball joint by itself

Welcome to John the Tinker's Blog.

Why "the tinker"? Well, I've become a bit of a Vernor Vinge fan. In "The Peace War" he calls people who make tech gadgets and software for hire "tinkers." That's what I do too. I like to make stuff, both for money and for fun. This blog will be my place to share pictures and descriptions of things I've created. I'll also include how-to information for some of the projects.

You'll see some software, but mostly models of trains, remote controls airplanes, boats, and cars. Also, I have a 3D printer (FDM, prints in ABS plastic) I have been experimenting with, so you'll see some parts from that.

I hope you enjoy it, please comment at will.