z3_2drive Posted February 12, 2013 Posted February 12, 2013 (edited) The previous attempt at a large scale car failed because it was not strong enough for the drivetrain, and my attempts to make a sturdy chassis around it were not so great because of the vertical placement of the buggy motors. I have sitting on my desk now, a 2nd attempt at a large scale rc, with a much more simple and robust suspension, which will eventually use the new f1 hubs, at the moment I used the dark bley mog hub because of it's dimensions. I placed the buggy motors in a clever fashion, so there are many bracing opportunities for the rest of the chassis and the rear axle. Because of the eventual weight of the vehicle I had to put a combination of various shocks to get a perfect balance between soft and stiff-soft enough that it will absorb bumps and jumps but stiff enough that it wont bottom out (hit the ground) because there is a lot of travel and not that much clearance, and I will use the same wheels/tires as on the 42000. Photos: Enjoy! Edited February 12, 2013 by z3_2drive Quote
DLuders Posted February 12, 2013 Posted February 12, 2013 @ z3_2drive: What is the voltage of those batteries that you have wrapped in black electrical tape? Quote
z3_2drive Posted February 12, 2013 Author Posted February 12, 2013 @ z3_2drive: What is the voltage of those batteries that you have wrapped in black electrical tape? about 10 volts each Quote
timslegos Posted February 12, 2013 Posted February 12, 2013 looks promising, how well does it perform? tim Quote
z3_2drive Posted February 20, 2013 Author Posted February 20, 2013 Ok, here's a delayed update- stiffened the suspension by changing for extra hard shock, and moved the mounts one stud out on each side. Built a large section of the chassis and placed batteries in. Made a simple flat bottom to keep electronics clean and free of dust, but I expect scratched panels sooner or later... Photos: Now just need to figure out front axle/steering which will be hard without new hubs... I hope to go through with this and finish it! Quote
Someonenamedjon Posted February 21, 2013 Posted February 21, 2013 Wow! Looks really strong, can't wait to see the final model up and running :D Quote
z3_2drive Posted February 24, 2013 Author Posted February 24, 2013 Finally, I've finished the chassis but i'm calling it a prototype because I don't know how it will perform. It weighs in at about 864 grams WITHOUT wheels...so most likely will be a high speed but slow acceleration... It has decent steering angle (im using placeholders for new hubs) --- I made a quite aerodynamic-looking underside: Hope it turns out good once hubs become available for good prices! Quote
timslegos Posted February 24, 2013 Posted February 24, 2013 The bottom skid plate reminds me of many traxxas rc cars (i have a t-maxx 3.3). It looks great so far, could you make a video of it running on those 10 volt batteries? tim Quote
skppo Posted February 24, 2013 Posted February 24, 2013 I wish lego made a power functions radio reciever and controller. Driving a car with this sort of power via IR will be tough. Quote
AndyCW Posted February 24, 2013 Posted February 24, 2013 I like the buggy motor integration and the underside. Hopefully IR control can keep up with available power and speed. Keeping the suspension soft will help with the differential and overal tire contact. If front suspension is effectively softer than rear, then it may lift a rear tire on corning and with an open differential cause wasted power. v/r Andrew. Quote
z3_2drive Posted February 24, 2013 Author Posted February 24, 2013 The bottom skid plate reminds me of many traxxas rc cars (i have a t-maxx 3.3). It looks great so far, could you make a video of it running on those 10 volt batteries? tim I wish lego made a power functions radio reciever and controller. Driving a car with this sort of power via IR will be tough. tim I will if I have the chance , and skppo I agree on that Quote
z3_2drive Posted March 1, 2013 Author Posted March 1, 2013 (edited) do you guys think this chassis is worth a rebuild? since I have no hubs yet I made a makeshift wheel placement that will model final outcome and it looks... weird(too wide for its wheelbase), but dont want to risk taking this apart-maybe i'll make a separate lighter, downsized chassis, possibly live axle in the rear Edited March 1, 2013 by z3_2drive Quote
Someonenamedjon Posted March 1, 2013 Posted March 1, 2013 I don't think the chassis is worth the rebuild, i think you should go with the lighter design no.2 for testing. Quote
The_Skirrid Posted March 1, 2013 Posted March 1, 2013 Don't forget a cheap way of gaining a few % stiffness, esp, rotational/torsional is to replace all the friction pins with old style non-slotted ones. I have a batch of 30 or so that are monstrously hard to insert and remove. Quote
Lipko Posted March 1, 2013 Posted March 1, 2013 What do you mean by risk? Forgetting how it was assembled? If so, just take it apart and make photos during the procedure. Or model it in a CAD program, the chassis doesn't seem too complex to do so. Quote
750ACE Posted March 1, 2013 Posted March 1, 2013 I don't think the chassis is worth the rebuild, i think you should go with the lighter design no.2 for testing. What do you mean not worth the rebuild? Hubs are the only parts missing from testing. Did you build one with the same motors? Quote
Meatman Posted March 1, 2013 Posted March 1, 2013 What size wheels are you planning on using? I am not sure if the new hubs would be a great idea for a motorized model. As mentioned here at eurobricks before, they have kind of a loose fitting. Quote
Someonenamedjon Posted March 1, 2013 Posted March 1, 2013 What do you mean not worth the rebuild? Hubs are the only parts missing from testing. Did you build one with the same motors? No.. But i don't think he should take it apart, but build a second chassis. Quote
z3_2drive Posted March 11, 2013 Author Posted March 11, 2013 UPDATE: As I mentioned in another topic, I bought all new suspension hubs and new thin 5l liftarms with axle holes from lego direct, but I have not received them-hopefully soon this week. In the meantime, I have made a completely new chassis-same power but lighter and smaller And here are pictures ^also went for a mostly light bley chassis this time... ^like the previous chassis I'm using placeholders for the new hubs, and the light bley half-bushings are placeholders for the new +ooo+ thin liftarms. ^there'll be decent travel in the front and rear axles ^three 20t gears will in theory keep the differential from skipping teeth... ^my 10 volt batteries are held in place by a simple cage and a liftarm on either end. ^front side. ^I'm glad the pin w/ bushing exists-it's a must have for easy deconstruction. I'm happy with this "chassis ver. 2" , hope you are too! Quote
timslegos Posted March 11, 2013 Posted March 11, 2013 Looks great, I really want to see a video of it driving. tim Quote
z3_2drive Posted March 14, 2013 Author Posted March 14, 2013 Looks great, I really want to see a video of it driving. tim Thanks! But I'm still waiting for the parts to arrive But this long wait has allowed me to rethink and perfect a few aspects of the chassis-I changed the rear suspension a bit for more travel and a more buggy-type look, and the front shock mounts have been braced and connected to the servo, along with both receivers being placed in an efficient and compact manner. Pictures: ^steering angle seems good. Enjoy! Quote
camaudio Posted March 14, 2013 Posted March 14, 2013 looks great but that front suspension looks shakey Quote
z3_2drive Posted March 14, 2013 Author Posted March 14, 2013 looks great but that front suspension looks shakey it is now but should be better with new thin liftarms Quote
Bzroom Posted March 14, 2013 Posted March 14, 2013 (edited) How do you plan to do the drive shafts? edit: Oh I see, the telescoping universal joint in there. Using universal joints on these cars always seems like the weakest part. I think if i was building a rock crawler, or high powered car, i would try to use the yellow 4 tooth gear. Edited March 14, 2013 by Bzroom Quote
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