Posted June 17, 20231 yr Heyy everyone! PHOTOS : https://bricksafe.com/pages/vergogneless02/the-new-mini-brushless-trophy-truck---v1- Today, I come bearing a brand-new project, or rather, the evolution of previous models. I hold a deep admiration for my initial Trophy Truck: However, it possessed certain flaws that I have partially rectified with the Hot-Rod Cross: Yet, as an eternal dissatisfied soul, I knew I could achieve even greater heights! To be precise, the objective is to remain within the same scale, but with the following enhancements: Incorporation of ball-bearings parts Maximum steering angle Further elevated ground clearance Improved trade-off between speed and acceleration And above all, a fully pneumatic suspension system. Regarding its dimensions (for now): Length: 16.5cm Width: 12cm with wheels Height: approximately 8cm Weight: 372g (including the battery) Now, let us delve into the specifications: A2212 1000kv Brushless Motor Surpass Hobby KK 35A ESC Gray Geek Servo 360 Dumbo RC X6PM-350 + X6FG receiver (with an integrated gyro!) 3S 450mAh battery Carbon fiber rear axle Ball bearings on front and rear axle Gear ratio: 1:2 The design is still in its infancy, but as usual, I will make the most of the limited space I have available. More updates will be coming soon, along with videos, as usual! Any feedback is welcome; the utilization of pneumatic suspension is a first for me, but it promises to yield truly satisfying results. Edited June 19, 20231 yr by vergogneless
June 17, 20231 yr looks promising. i am curious how it continues and look forward to the videos as they are superb!
June 17, 20231 yr Author @pow Thank you, I appreciate it I have made good progress so far; the body is taking shape, but I still need to work on the front and rear sections. I'm also wondering if the cabin is too tall. Ultimately, I will need to connect everything to the pneumatic system !
June 17, 20231 yr Author Here, I have achieved something that pleases me in terms of design. I will see if it continues to please me as the days go by. Everything is working wonderfully; the pneumatic suspension allows for various adjustments and provides a delightful driving experience. I have driven for about twenty minutes, and it feels like there's a little cloud beneath the body. In the photos, you can see the range of ground clearance, from the minimum to the maximum. The advantage is that at the minimum setting, the center of gravity is significantly lowered, which is perfect for the road and high-speed runs. As for the maximum adjustment, it's more suitable for off-road trails! In terms of performance, with the 3S battery and the 1:2 gear ratio, it's monstrous for a 470g model. It provides a lot of enjoyment and fun. All of this will be presented in a video soon, as usual!
June 17, 20231 yr That steering action seems to change drastically from it's low position to it's high position, how's the handling? It also seems like those pneumatic cylinders are more for ride height adjustment rather than working suspension, is that correct? It does look like some fun to drive and while not exactly my cup of tea, I would like to see more LEGO elements used where possible.
June 18, 20231 yr Author @Johnny1360 Yes, it's true that I noticed something was off with the steering, visually speaking, but I can't quite put my finger on the exact term for this phenomenon. I believe it's because my steering rack is positioned behind the pivot point: The lack of space with the use of hubs forced me to do it this way. It does affect the handling indeed; the maximum steering angle is excessive (I can do a full turn within a diameter of less than 60cm). While driving, it's not at all suitable as the vehicle easily flips, especially with this power. But I can reduce it by at least half, and then it's fine. The advantage is that I can adjust the steering angle according to the usage or terrain, directly on the controller. Regarding the pneumatic system, it serves to adjust the model's height, but it also functions as an air suspension (although there needs to be air inside, as at the minimum level, there is no suspension effect until you pump it again). The more air there is, the higher the vehicle will be, and the stiffer the suspension. With half-filled air, the suspension behavior is very similar to that of an oil-filled shock absorber. It's very supple, and the vehicle compresses without bouncing. Watch this video; I'm using the exact same principle. The only downside at the moment is that I have to pump it every 2-3 minutes. But I've ordered a mini tank air reservoir to significantly slow down this phenomenon. "more LEGO elements used" I can understand that sentiment. I feel the same way when I see constructions that only use LEGO elements :D
June 18, 20231 yr Author Finally, when I woke up this morning, I decided to revisit certain aspects of the design, particularly the front and side sections. It's more harmonious now, and there are no longer any issues with the pneumatic system rubbing against the aesthetic elements at the front. I also wanted to make a quick note about the ball bearing pieces. Regarding the hubs, they are excellent with almost no play. In my opinion, they are becoming essential. Not only do they securely attach the wheels, but they also eliminate friction. As for the flanged bearings, I have a more nuanced opinion. It depends on their specific use, to be honest. They are slightly curved. It may not be clearly visible in the photo, but it can be problematic as it can cause friction and minor misalignments that have an impact on the LEGO structure. The ball bearings appear to be of good quality, but they might be fragile. They can be easily removed, and there is an unpleasant amount of play due to the fact that the ball bearings are only half the length of the hole. The diameters are not exactly the same for the remaining length (where there are no bearings). Regarding 3D printing, it seems that the quality is inconsistent. Some holes are looser than others, and sometimes they don't even hold. The same goes for the cross; your axle might slip on its own. But overall, I believe we need to familiarize ourselves with these components and learn to integrate them intelligently. Regardless, I do feel a difference with this model (using a combination of hubs and flanged bearings), and that's quite positive. There is less braking/drag effect when not accelerating due to reduced friction. As a result, the wheels travel a greater distance in freewheeling mode, leading to less wear on the parts. I will provide further feedback after thoroughly testing it over extended periods of time.
June 18, 20231 yr Cool, thanks for the informative response, I do think it looks a bit better after your update. Regarding those bearings bowing the piece, I can see where that could cause some issues down the line, so I will avoid using them, thanks. As far as the pneumatic suspension, that is an interesting concept, that I will investigate further, may adapt it for my own use even, if I can round up all the spare parts. Looking forward to your next project, enjoy.
June 18, 20231 yr Author @Johnny1360 For the pneumatic system, I use Mould King equipment, which is very good and affordable. The complete set on the Miguba store on AliExpress is around €25 (includes everything, and the price is the same for larger cylinders). If you add €8, you can get an air tank, which I recommend for added comfort, especially for larger scales. See you soon, and thank you for your message. On another note, I had an accident earlier today. I had a frontal collision on the right side with a curb due to a moment of inattention, and it would have affected any RC vehicle of this scale. I broke a cylinder, but I repaired it using super glue and baking soda. It's now even stronger than before, but I still ordered a batch of new cylinders. I will replace this one for aesthetic purposes, and I'm planning on using a different model with a closed and non-adjustable circuit. It takes up less space and doesn't require "recharging." At the moment, I could also replace the entire current system with shocks, but I've already started working on a new version that will have them, which I will showcase in an upcoming WIP (work in progress). Therefore, I'll set this model aside for now until I receive a brand new cylinder for the video.
June 19, 20231 yr Thanks for sharing your many information. to fix the unwanted change in the caster angle, would it be possible to use such modified swing arm design (just a fast mock up)?
June 19, 20231 yr Author @pow Thank you for your interest ! I have several challenges that are accumulating regarding the front section. I don't have many options. I'm working in a really tiny space because I also need to fit in the servo motor. So, I don't have much width available, and on top of that, using a hub alone takes up 2 studs in width. To make things more complicated, I need to ensure a minimum of 2 studs of ground clearance and that it's sturdy + incorporate the suspension system. It's a real puzzle, haha. As for this model, I can't say it's problematic. I actually drove it earlier, and there's nothing wrong with the handling. I'm just concerned about its durability. That's why I'm simultaneously developing another version of the Trophy Truck that would address some of these issues. The big change is that this time, I decided to work with the servo motor in a vertical position. I managed to design a front section that is more robust, just as compact, with an improved pivot point, and now offers 3 studs of ground clearance! I will be using shocks to change things up a bit. I'll show more details about it soon.
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