1980SomethingSpaceGuy Posted March 19, 2020 Posted March 19, 2020 (edited) Edit: current state photo: Long time have I looked down at electric motors in Lego. I had in mind the poor battery life, connector quality and motor usability of my first Technic motor set, 8054. All of these were miles away from the brilliant design of the bricks themselves, which could withstand years and all sort of rough play and keep all of their (friction) power. Plus the battery packs were cumbersome and the very fact that something was consumed when playing didn't match the philosophy, in my mind. I didn't want any more electric set. Years passed. NXT was introduced and I got into it. Being able to program my own contraptions' behavior added a lot to the fun of designing stuff. Then I discovered GBC and I knew I needed a few PF motors. From there, being able to remotely control them for other purposes of course adds to fun, so I why not also get a set with a remote ? Finally, I recently got my first PF servo motor. Just because remotely controlling a motorbike without one makes things a bit too hard. So here I am. With finally enough stuff to build my own RC vehicle. I first gave motorbikes a try, but they need quite a bit of speed to gain stability and there isn't much free floor surface in our apartment. I had to test the prototype outside, and was not very happy with the first iterations; I achieved stability and control, but the minimum speed was a bit high and the lean angle too small. The kids asked each day when they could try the new build. As I was explaining my 5yo daughter that designing a motorbike was not easy; she candidly asked why I was not making a car ? Of course my first thought was "because harder problems are more fun!". And then scraped my Red Buggy to add 2 more wheels and a differential. I only kept suspension on the challenge list and built my first usable Lego RC vehicle. It's dead simple, not optimal on any level, but my daughter loves it! Edited March 29, 2020 by 1980SomethingSpaceGuy Quote
Gray Gear Posted March 19, 2020 Posted March 19, 2020 It wasn't exactly what I expected to see when i read the title, but it counts I guess But what the hell is that rear shock absorber setup? Never seen something like this. I would understand if the mount of the long shocks was made to move from side to side to increase rear axle flexibility, but since it isn't I just cant see why you would use 2 different sized shocks As a child's toy I can see this working very well, the 5x11 frame in the front should be able to take any impact that might happen The unprotected front wheels probably are a weakspot when crashing into something, but what can you do... Quote
1980SomethingSpaceGuy Posted March 19, 2020 Author Posted March 19, 2020 Well... The motorbike shocks were added after everything else was built because I underestimated the overall weight and the rear proved too soft. Rather than redesigning the whole thing, they were just added on top. It's just a couple hours' kid toy build ;) And indeed, the wheels are a bit exposed.. But the speed is pretty low, which helps! Quote
1980SomethingSpaceGuy Posted March 22, 2020 Author Posted March 22, 2020 This quick build left a lot to be desired. I took some time this weekend to rethink this fellow a bit. First, since I want full suspension and a differential, this is probably the narrowest I can do with my pieces: a couple steering CV joints on each side of a 5 x 7 frame. The steering on the other hand, was a bit tricky. All I have as steering specific parts is 4 of those guys: And I finally figured out why I always had a hard time building something clean with these. They're meant to be used with this fellow: Which imposes the width of the drive train. So I'm using this one instead: The small one is meant to be used with an 8 tooth gear, and the big one width a 12 tooth gear, so they have different rack height to base. Thing is, a quarter rotation (like the servo does) on a 12 tooth gear causes more rack translation than the steering arm can handle. So I need to use the 8 tooth gear on the big rack. Which requires the rack to be offset by some fraction of a stud length. This is the solution I came up with: A double rack to prevent sliding, and 1/2 pins to raise the racks. Building something strong around this was not trivial. In the first iteration, the XL motor was driving the differential directly. The output speed was too slow I thought, so I geared it up. A bit of trial and error was required since the XL motor has quite some torque. Having that figured out, I was a lot happier with my simple RC platform: I then put myself to modular body design. What you see here are literally all of my red panels. I tried to make the most of them. The body wraps the chassis tightly and is held by only 3 pins and 4 axle in holes. A panel on the side lifts up to allow access to the battery switch. I'm a lot happier with it now. I don't think I could do much better with my current parts pool. Thanks for watching! Quote
AndyCW Posted March 23, 2020 Posted March 23, 2020 I like the stopper pin on the battery box switch Quote
astyanax Posted March 23, 2020 Posted March 23, 2020 I for one love the new bodywork, curvy and edgy at the same time! Quote
1980SomethingSpaceGuy Posted March 23, 2020 Author Posted March 23, 2020 10 hours ago, AndyCW said: I like the stopper pin on the battery box switch Yep ! The small details count. 4 hours ago, astyanax said: I for one love the new bodywork, curvy and edgy at the same time! Yeah.. It's neither cute nor aweful Anyway, I enjoyed the journey in RC vehicle design and even if the limited amount of (especially dedicated) parts was quite a challenge, I think I might build something more consistant soon. Quote
1980SomethingSpaceGuy Posted March 29, 2020 Author Posted March 29, 2020 (edited) On 3/23/2020 at 9:17 AM, astyanax said: I for one love the new bodywork, curvy and edgy at the same time! I smoothed it down a bit. I think it's better now. Needed to fix that headlights setup too. And that was for our episode "How to make a car without car parts".. Thanks for watching! Edited March 29, 2020 by 1980SomethingSpaceGuy Quote
astyanax Posted March 29, 2020 Posted March 29, 2020 20 hours ago, 1980SomethingSpaceGuy said: I smoothed it down a bit. I think it's better now. I'm really squinting to see the difference... Is it the roof? (You can imagine how angry my wife is when she gets back from the hairdresser and I don't notice anything... ) Anyway, what I specifically love is the "judicious" use of the old-style panels! (I have 8448 & 8458 sitting on a shelf next to me now, and they still look so good...) Quote
1980SomethingSpaceGuy Posted March 30, 2020 Author Posted March 30, 2020 14 hours ago, astyanax said: I'm really squinting to see the difference... Is it the roof? (You can imagine how angry my wife is when she gets back from the hairdresser and I don't notice anything... ) Anyway, what I specifically love is the "judicious" use of the old-style panels! (I have 8448 & 8458 sitting on a shelf next to me now, and they still look so good...) Yes, it's the roof. I gave it a smoother haircut. It's 1 stud lower, and now tucked by the grey bar behind to flush with the A pillars. But indeed, it's subtle. Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.