TechnicSummse

Oh, i thaught you mounted it on the wheel-axle. But its mounted on the motor-axle. But still... the 3x5 L-beam should not touch the axle, thats what i meant. You can put the Pullback-motor to your chassis, and use only its axle-hole as bearing.

The pullback-motor will just shorten your required track. It is pretty much the same, then using a gearbox in our case. You could use the pullback-motor as bearing. As you mounted it now, it produces extra friction at the axle. But ( i know you didnt want to talk about :D) the biggest problem are the wheels. They have just a terrible rolling resistance.

awesome video.... and really nice car!!!

Since i cant testdrive my newest speedracer because of the rainy weather, i decided to clean up my "in progress moc corner" and found this: A as small as possible electric doubleswitch, wich you can use, to control 2 different motors with the same RC output. You can simply select wich one you wanna use. At the same time you can use it to control a gearbox, or output-selector, as you can see in the video. The idea to invent this, was, to realise as much functions as possible in a rc-model, with a limited amount of receivers (in my case just 1 RC-unit). You can use the auxilary output of the RC-unit to control the micromotor, and thus switch between 2 different functions ( for example drive and a pneumatic compressor). The output-selector can be used, to switch for example a servormotors output between steering and pneumatic-switch. "Why so complicated, you could just use the auxilary output for the compressor" -> well... you could do that and beeing limited to the auxilary current limits (~500mA). Also you wont have the gearbox/output-selector then ;) While using this, you can power your compressor (or what ever you want) with the "unlimited" power of the RC-units buggy-motor-output. AND fine-controll it with the 3-step forward, 3-step-reverse-control. It is also possible to control this with the RC-units steering output instead of the micromotor... like that you still have the auxillary-output free for use. How it works: The trick here, is to angle the 2 switches axles by 60 degres (45 would be perfect, but this is ok ;)). But you need to try the right 60 degres angle... only 1 position works, otherwhise you will have 1 motor switched on in one position, and 2 motors beeing on in the other position. The gearbox/ output-selector in the video can be simplified a lot, this is just to show, how it could work. I am pretty sure, there are some more things you could do with it... also with regular power functions ;)

I had the battery-box in flat position, but this needs ~15g more weight :D Just an idea wich needs testing like this... as i told... since i cant doing any testdriving at the moment, i am just building and building and changing and changing :D I used them in ALL earlier models, but just because they were needed (because i dont have any axle beeing longer then 12 studs). In this setup i could use a 12 stud axle the first time. I dont like the connectors really, because the axleholes sometimes are not 100% straight. Another point is... since the axle goes in there just 1 stud on each side, they tend to bend even more then a well fixed axle. Sure i did that :D But the micromotor is not srong enough to move the battery-box-switch :( Well... my 2-motor-record racer also used this kind of setup... bearings at the motor-pinholes. This was just a 1:1 copy of my 2-motor setup, usable with 4 motors. Dont think i will ever test this... but as i told before... im just building and disassembling, to find any better idea :D Its pretty much like a brainstorming

As promised, i will show you finally some new pictures of the actual progress. The weather here is pretty bad at the moment, so i could not do any testdriving in the last few days :( Since i could not do any testdriving, i continued disassembling and rebuilding all the time. Maybe i lost some good setup like that... but i couldnt sit there doing nothing :( So i just builded and kept the model, wich felt to be the best setup so far. Tests coming soon... not today, because it is still raining like there would be no tomorrow. A so far untestet 2:1 gearing setup idea __________________________________________________________________ Yesterdays result: _______________________________________________________ current setup... lightened it a bit, and added the speed computer. Gearing is 40:12 now, using just 3 gears (2x 40, 1x 12), and a total axle/beam-friction of 6x thin beam (2x at the frontwheel, 4x at the rear wheels) Total weight now (including speed computer) is 1030g. @Marxpek i think we will end here with nearly the same specs, since we are aiming to the same small point as goal. I decided to make a small little video instead of some pictures, showing also the booster-switch and the steering in action.

Nice to see finally some of your results :D I think evryone of us startet with something like 20+ kph. Its pretty ok as first result. Dont you have a steering yet? How you you make such a clean picture with white backround?

Nice idea with the suspension... i would be glad if i had so much parts, just to pick out of them :O Seems like you have every part wich you need... just grabbing into your chest and pulling it out :D Why you dont put the pulleys directly together on the axle? I think its way more fragile, the way you have done it now. By the way... bending the antennas is not a good idea... i tried it also... you will have like 80% less range. It looks nice, maybe helps a bit with air resistance, but your range is going down close to zero :( ________________________________________________________________- Your new track seems verry nice... i have a similar track, but what are you doing with the bikers? I tested on our bike-road once, and decidet that its way to dangerous, a bike could kill my car. What's your total weight with the actual setup? I will post my new pictures tomorrow... im too tired now to upload them :O

I'm sorry to hear that :( As i told few days ago... this will be fine indoor, but doesnt work outdoors. I testet this wheel allready: And it was allready way to bumpy... -> since we dont use any suspension, we need rubber at the wheels. Also the radius is to small... it will get stuck on verry small stones on the road. That's the reason why you meassure slower speeds here, compared to your other wheel Nothing really spectacular... just another frame/gearing-setup. I geared 40:12 at the low-speed-output now, but using just 3 gears in total. At the moment i use 6x (could be reduced to 4) thin beams as bearings with this... 2 on each side of the gear, and 2 on each side of the wheels... (just a half bush as space-holder on each side). So there should be close to no axle-bending But i will show this at the evening :)

@Sariel built a simple solution for this: http://sariel.pl/2011/06/rc-motor-output-selector/ But as @Marxpek wrote, you will have a lot of additional friction here... 11 times a axle-pinhole-friction, just at this. (we try to reach a maximum of 2-4 axle-pinhole-friction in the whole model) My feeling is more, that beacause of the verry low radius of it, the axle will be pulled up or down more by the driving gear (and like that be pushed at the pinhole, producing friction), instead of beeing rotatet smoothly. I tried a new idea with my model now... but same problem as @Marxpek its a bit wet outside :D I cant testdrive at the moment :( I will post some pictures in my topic at the evening :)

@Marxpek uses a 40:16 at the high-speed output with his actual racer in this topic. I used a 24:12 at the high-speed output with my 34,8 km/h 2 motor record-car. The actual higherst result (38,7 km/h) i could get with a 24:8 at the low-speed output. But i ve got the feeling, that the 8 teeth gearing is not the best at this use... i think a 36:12 would be better then a 24:8... but its just a feeling

We talked allready about htis one: But @Marxpek is afraid they will break to fast. And i know from similar small wheel wich i testet... that running them on a regular street doesnt work. This would be a really nice wheel, if you had an indoor place wich is ~150m... But dont waste more time for your meassuring-system then for your car... i would love to see some results here soon :D

Ah, now i see, how your steering works... its different then mine. But this is also a nice and clever idea. What i dont linke there... it is way to stable and heavy. I designed my frontpart, to be verry loose. When crashing, the axles can be pushed back, and the beams will bend outwards. You can call it something like a crumple zone. Like this, the RC-unit is protectet. I think if you crash with this steering setup, all the crashing energy will go staright to the first RC-unit(s pinholes) I love this wheel :O I think i need to buy one of those :D Well at the end i didnt buy any special parts for this project yet. I just used the best what i could find in my partlist. I got the rearwheels for free when i baught some mixed parts, and i decided to like them more then the Claas Xerion-wheel. Long time, i was using this one as frontwheel: http://rebrickable.com/parts/55978/tyre-37-x-22-zr/ from the getaway racer-set 42046 But it was worse then the one i am using now. My actual frontwheel is smaller and has one big plus... it has a pinhole, and not an axlehole... meaning it can freely spinning at the axle, AND the axle can spin in its bearing-points...it spins soooo good :D If we could race indoors, i would use this one: http://rebrickable.com/parts/2815/technic-wedge-belt-wheel-tire/. That would be the best possible wheel at all

Looks really nice so far :) But with the wheels beeing close together you will need support wheels. Otherwhise you will scratch your outer buggy-motors on the ground ( or the RC-unit). I see you are using thin beams as bearing now also ;) What i dont understand here, is your steering...? Can you make some close up pictures there? But i guess this can be 38+ or even ore? :D

No strange smellings so far... im really taking care of that :D I can reproduce the 38+ many times with the 24:8 gearing setup like in the first post of my WIP-topic. I am working on a 24:12 solution now, with low friction and stable bearings. But its really hard to get that combined... with my 2 wheels i need 4 bearing points (2 on each side of the wheel). With 2 motors, it was ok to have just 2 bearings (at the outer side of the wheels), but 4 motors are too heavy, and axle bends to much without an additonal bearing at the other side of the wheels. With the 24:8 gearing at the lowspeed-output this was no problem, i could use thin beams at all 4 points. While using the highspeed-output, i can not transport the power outside the motorcase. I could use a 40:24 gearing to come outside there, but thats just a 1:1,6666 and thats way to low. And as long as i need to stay within the case, i need to use the motors pinholes as bearings... meaning 4 studs instead ot 2 studs of axle/beam friction. I could also use a 40:20 gearing ( i love that, used it in a few trys of my 2-motor-versioin), but here also is the bearing problem. I need to use thick beams for this, because there are no angled thin beams, wich would help here :(

How do you break? The RC-unit must be strong enough to take this with 2 motors... because every simple rc-car is driven like that... breaking means reversing the motors. At the moment a fakt is... we dont know if it is ok for the rc-unit to controll 3 motors, or it is not... i know it could be a not so good idea... but i will try to find out some further information about this... Im trying to find out what exactly happens, if you reverse the motors while the are running.

Uhm... yes i have to tell you this :D

hmm wich ones do you mean? can you post partnumber or a photo please?

I like the PF-train-idea. But again here you will need 2 to replace 1 buggy motor... meaning you need 4 to replace 2 buggy- motors. And at philos page i found something wich could bring in another problem here: Sounds like they could have problems with pulling some weight... What do they cost?

Thats what i meant... Problem here is... the battery-box is mountet at the outer pinholes of the rear buggy-motors. And it fits exactly between there... moving it will mean to construct a new frame behind the rear motors, and i was intendet, to use the battery-box as frame there. I will redesign this again

As you do... im allways looking for a btter track. The Penny-market parking is ok (pretty clean and flat) after 20:00 at the evening, or at sundays. But some people drive there also late at the evening, and this gave me some dangerous situations...running down the street, fully concentratet, steering your car...and boom... there is a real car infront of you... not really a nice experience. Ive got a second track... wich is ~200m and flat... but this one is pretty dirty, and has a little problem... at the end, there is a wall... and as you can imagine... i hit that wall a few times. Sometimes beeing out of range to break... sometims slipped off gears were the problem :( What we would need is something like that:

10m? What do you wanna test on this track? :D A pullback-racer? :D You need ~100 m or better 150... But indorrf driving would solve a lot of my problems... that would be nice *dreaming*

Todays results: -> nothing good :( I just tested yesterdays building resulst, without any changes, because i decidet to not like this design so i will disassemble it again. And i didnt want to loose a chance, if this maybe could give a good result, so i testdrove it. -> 4 Motors gave only 35,5km/h :( A few problems leading to this could be: - Axle bends to much, and so wheels fidget - too low ground clearance breaking at small stones - look the last picture :D The only good thing i found with this test -> with the 24:12 gearing the battery-box-protection doesnt kick in.

Well you can use 2 L-motors per side, 4 in total... should givie you similar results then using 2 buggy-motors. But with the geartrain, and additional axle-beam-friction (wich you need at the geartrain) you wont come to the limit. But 4 L-Motors still could reach 30+ i guess :) But at the end... 2 buggy-motors are cheaper then 4 L-motors.. arent they?

Comparing L-motor vs buggy-motor in this chart... http://www.philohome.com/motors/motorcomp.htm ... shows, you would need 4 L-motors to get the same mechanical power then 2 buggy motors, while they consume the same amount of power. But you would need a 4,5 times higher gearing... meaning a 2-gear-transmission wont work anymore, you will need a 40:8 upgearing + another 20:12 for example.