I really liked my old motor mounts for the Quadrotor. I made them on the lathe out of “Engineering Nylon” which costs very little, is easy to machine and can be found on eBay (search for “nylon round bar”). The motor snuggly fits into a 9mm hole and is fixed with two 3mm hex head set screws from either side. Another 3mm set screw goes through the bottom and bolts the mount onto the frame. To stop the torque from the motor spinning the mount I milled a 10mm wide slot into the bottom which fits over the aluminium frame.
I liked them because they are light, look nice and form an integral part of the frame (so no extra cable ties and fixings, just one bolt to do everything). The big problem made itself very apparent when I had a crash on the airbase; the motor hit the ground first and because there was no “give” in the motor mount I bent the arm and broke the motor (detaching one of the magnets).
This would never have happened in the old days – when the factory motor mount was attached to the frame with cable ties. It might have been ugly, but the cable ties would snap long before any other damage could be done.
So, how could I improve my nice looking “purpose built” motor mounts to add a weak point? The answer is in the next picture:
Basically it’s exactly the same design, but with an added cable tie! This time I made the mounts in two parts: a base part which bolts securely to the frame and a motor part which sits on the base and is held down by a cable tie. There’s a little knob on the motor part which sit in the 5.5mm hole in the base part (at the bottom of which the hex-head of the set screw goes). This keeps the two parts locked together as long as the cable tie is in place.
In a crash the cable tie will snap and the motor part will detach – hopefully protecting the motor from damage and protecting the frame in the event of a “motor-first” crash.
Have I tested them yet? Well, no. I’m not going to crash on purpose!
Last year I decided to set myself some hobjectives. These are like resolutions but specific to the domain of hobbies: character building, life enriching sort of things rather than the usual “cut down on the booze, swear less, get a new job” sort of stuff.
How Did I Do in 2012?
- Sleep in the back of The Duke – Pass
- Learn to fly my tricopter – Pass
- Smelt aluminium at home – Fail
The first one was a resounding success. Though it may annoy the ex-military purists, the back of The Duke is now kitted out for sleeping rather than helicopter maintenance. There’s a comfy mattress, some dust-sheet-curtains, boxes of outdoor equipment and emergency rations. There’s even a flat-screen TV in there for FPV flying, though I haven’t managed to get it to work to my satisfaction yet.
I ordered my first shipment of multi-rotor parts in November of 2011 and had my first DIY tricopter up and running just before Christmas. Unsurprisingly I was a pretty crappy pilot to start with so getting better seemed to be an obvious hobjective for me. The original tricopter is hanging on a nail in the garage (victim of yet another broken servo) and I am now a quadcopter convert. I’m much better at flying, though still have a long way to go. I’ve done FPV too, which is a bit of an added bonus.
Smelting was a total fail. Partly due to the weather and partly due to the lack of a big metal cylinder I just never got the stuff together to try it. Dr Johnson is signed up as an official project partner to get this one licked in 2013!
- Smelt aluminium at home – with Dr J’s help this should be easy enough. We just need to buy some protective clothes and a few bags of charcoal and we’ll be good to go! Success will be measured on a small pile of ingots on the bench above an empty scrap bin.
- Finish the Duke’s Raspberry Pi brain – pull all the bits together to start The Duke tweeting about his adventures. Some niggles to work out around the power supply and the enclosure and some software to write then it should be good to go.
- Do some impressive FPV flights – get some long range flights done, preferably somewhere with a suitably high natural beauty rating. Capture some top-notch video footage of the sort that will make viewers raise their eyebrows and nod in mild appreciation.
- Make tasty bread in a Dutch Oven – I got a black pot for Christmas. Being able to make fresh bread from scratch anywhere in the world is frankly a vital skill. It’s a wonder I’ve managed to reach my 35th year without it!
I think those four should make for an entertaining year. Of course there are a thousand other jobs I need to get done this year in addition – The Duke’s gearbox needs looking at and I’d like to make a second ‘copter so I can crash twice before going home. There’s an FPV ground station to build and all sorts of tweaks to be made to the quad. Before I cook bread I’m going to have to do a chilli and maybe some southern-style barbecue chicken and ribs. I should really add some insulation to the back of The Duke and there’s no doubt I need to sort out the alignment of the tailstock on the lathe… you get the idea.
Today, logicalgenetics.com and danandtheduke.co.uk merged to make one Super-Blog! It seemed daft having two websites and two blogs, so I’ve pulled all the Land Rover posts into the Logical Genetics blog and pointed both addresses right here. You don’t need to change your bookmarks or format your brain – both logicalgenetics.com and danandtheduke.co.uk still work fine.
The old Land Rover blog won’t see any more action – I’ll be posting everything here. You’ll still get all the mission reports and photos of mechanicals. You’ll also get weird posts about Software, Machine Tools, Multi-Rotors and model flight and, well, just about anything else I can dream up.
If you just want to read about Land Rovers or Adventures, use the “Blog Posts” menu at the top to choose your poison.
Just a few interesting pictures from the last couple of weeks in the workshop. Have got the gearbox more or less back together now and have even made my own linkage for the overdrive.
Here’s the weird arrangement of levers and springs for the high/low ratio and four wheel drive selectors. Took me a while to work out how it all works!
Here’s the infamous castle nut which lots of people bang in with a cold chisel…
…but I made my own “600300 tool”. It took me about five hours to make from a chunk of 40mm steel bar. I had to use the lathe, mill and rotary table then sort-of-hardened it with blowtorch and case hardening compound. Well worth it for the 30 seconds of use it saw!
Next job was to make my own linkage and lever for the overdrive. The most complex bit was making a block which pivots on a steel bush, has a 12mm threaded hole for the gear stick and a slot with three 6mm threaded holes for the lever which links it to the overdrive. Pictures follow.
Tapping the hole.
I made three holes to allow me to change the angle of the lever when fitted into The Duke.
Here’s the end of the actuating linkage jobbie which I heated, bashed with a hammer and drilled.
Here it is in place. The L shaped bracket is far to flimsy but I think I might need a welder or a massive bender… as it where… to make a more sturdy one.
Here’s where the linkage links to the overdrive.
The whole caboodle.
The Duke’s choke broke a few weeks ago and, idiot that I am, I managed to order the wrong part to replace it. This left me with two options: return the part and get it exchanged for the right one or make a choke myself.
Given that I needed an excuse to play with the lathe, I decided to butcher the old and new chokes to make a new one of my own. The result can be seen in the following pictures. I am actually very pleased with what I’ve made, it’s quite solid and gives me more or less the same functionality as the original part.
It’s made from aluminium bar and all the parts were turned on the lathe. I even made the nut to hold it in place (which explains why it’s a bit wonky!). The shaft in the middle is steel as aluminium of that thickness would be next to useless.
The only bit not shown in the pictures is how I’ve attached the cable to the shaft. I drilled a 2mm hole a short way down the centre of the shaft, then drilled another 2mm hole through the side to meet it. I then hammered an L-shaped hook into the end of the choke cable and hooked it through the holes. To make extra sure it’ll stay secure, I soldered cable and shaft together. Not sure if the solder was needed, but it can’t hurt!
The Duke’s been running pretty well recently, so there’s not much to report on the blog. I’ve been spending my time in the workshop instead, making bits and bobs on the lathe and mill.
Last night, Dr J came round to make a dog to connect his capstan winch to his engine. They cost about £50 each on eBay – even for a copy – so we made one out of a chunk of 45mm bar scrounged from the offcuts bin at a local engineering firm.
First job was to drill an 18mm hole all the way through. Slightly smaller than the 3/4″ bolt that will hold it to the front of the crankshaft. We then bored the hole out to exactly the right diameter.
Boring out the “dog end”. This didn’t leave a massive thickness of metal round the edges (~4mm) so I’d recommend getting 50mm diameter bar if available.
Milling out the slots was very boring but went without a hitch.
I’ve also been working on The Duke’s NATO hitch recently, so here’s a couple of pictures of that. The packing plates are all home made (only two shown) and the swivel pin was made on the lathe out of silver steel. Not exactly the cheapest option, but it does mean it should be rust free for some time.
The hitch itself
The DIY swivel pin. I spent some time polishing it! I couldn’t find the split pin for the end for a reasonable price, so I’ve threaded the hole to take a 3mm screw as an interim measure!
So it cost very little to make the dog (wear and tear on the tools being the biggest cost) but it did take the two of us six hours, so I can see why these things cost as much as they do! I think it’s safe to say though, Dr J and I would much rather spend six hours using a lathe and drinking beer than paying somebody else £50 to do the same!