Thunderdonkey

I highly recommened the DS3225MG servo available from various suppliers on Amazon for about £20. I have a number of them, and I have found them to be highly reliable and very robust. Recent results from my torque tester: 5.0 V: 21.0 kg-cm @ 2.6 A 6.0 V: 23.4 kg-cm @ 2.9 A 7.4 V: 25.6 kg-cm @ 3.6 A Which is brilliant value for money! TD

I built my Capra in 2020, and I have had a lot of fun with it, but one thing always annoyed me about the design: the 98 mm width of the battery box. Having acquired a 3D printer, I finally decided to do something about it. The width of the battery box is defined by two plastic parts. It took me a while to get the design right, but I managed to push the walls out 5 mm on each side. So now I have a 108 mm battery box. The parts themselves are very complicated. These pictures show a new printed part beside an original part. Outside view: Inside view: The change in external appearance is barely noticeable. Capra is a very good crawler and now I can use my favourite batteries in it. TD

Here is my home-brewed torsion-chassis Kri-Kri. It uses Bully II axles and Etronix 27t motors. There is an extra 250g of lead in each of the Axial front wheels, which have Bully tyres for rock climbing. The rear tyres are GMade Bighorn to give more grip in loose terrain. The Kri-Kri thrives on really rough ground and the loose sharp-edged rocks that we get in old quarries around here. The high-clearance chassis makes it easy to get up steps and over big rocks. It even manages long grass and rushes without trouble. Top speed is 10 kph on 2S, and 15 kph on 3S. I tried the two-stick setup that aPpYe uses, but I found it too complicated in practice. I use an FrSky Taranis X9Lite, with throttle on the left and steering on the right. The left shoulder switch selects 2-wheel or 4-wheel steering. The right shoulder switch selects 1-stick or 2-stick 4-wheel steering. Switch A up or down selects forward or reverse bias for climbs or descents to ensure the car stops with the stick neutral. Switch B up on all my cars is the Kill switch and the Tx will only turn on with this in Kill position. Centre position is unlimited power. Down engages the rotary knob for for power limit from 20 to 60 %. Switch C up or down selects Dig or rear freewheel. With Dig on and 4-wheel steering Kr-Kri can almost turn in its own length!

So what's your favourite flavour?

Don't sell the Capra yet! It just needs a few tweaks: Pen springs in the shocks and lead in the front wheels. Oh, and a 3S LiPo! Mine also has front brass portal housings and a bull bar to protect the headlamps.

If the axle will only rotate one way, it is probably the diff jamming. I built my goat from the kit and noticed this effect. I fixed it by generously greasing the diff.

I believe that there are occasional Crawler Comps at Black Rocks. Can you tell me exactly where they are held? Presumably they have to close off part of the park?

Here's my MOA 2.2: It used to be an FTX Ravine, now it's a Ravine Plus. Pit Bull Rock Beast II tyres, new foams front and rear, home-made high clearance suspension bars, lots of lead in the front wheels and the battery over the front axle. The tall, light-weight roll cage keeps it from doing dead insect impressions. There are always two wheels on the ground for self-righting. A complete electronics make-over gives full control over both motors and front and rear steering. It can even do the wall crawl trick (just!) The basic off-the-shelf Ravine is excellent value for money. The Ravine Plus takes it to a new level.