Top speed General disscusion

[Aventador2004]

Hey @Marxpek, @TechnicSummse, and @mocbuild101, I noticed you all had several conversations running in different topics, it was becoming unreadable. This can be a helpful place to post your stuff, inside this topic. 

Post at will, or ignore, your choice.

[PorkyMonster]

 Pros and cons... they probably want their own thread to discuss about improvements/features... However, I do see some values if we have this thread just to consolidate all the max speeds, along with vitals such as

• wheels dimensions
• car weight
• gear ratio
• types and number of motors (along with their control and battery units)
• distance before reaching max speed, and
• summary of key features that might contribute to any improvement
• link to their individual threads for further discussions

This way, there is one single place to look for speed records, and make quick comparisons on the merits of different configurations, while leaving car-specific discussions to their own respective threads.

So this thread could be renamed to better reflect this... Of course, feel free to ignore my post if it doesn't make any sense 

Edited July 7, 2017 by PorkyMonster

[mocbuild101]

I think we have all settled into our own topics already...

But I do agree with @PorkyMonster, I would be good to have a topic that combines all the speed records in a standardized way.

[Aventador2004]

Ok, I didn't expect any use yet, but if you need it, revive the topic.

Edited July 7, 2017 by Aventador2004

[Didumos69]

A question I have been playing with since the recent speed topics: Is there any example of a car that can actually shift gears while driving? All motorized vehicles with a gearbox I've seen need to stop to shift to another gear. I wonder if it could be useful in a speed car. Theoretically spoken it should be profitable if you can accelerate with a smaller gear ratio and shift to a bigger gear ratio once at speed.

Edited July 7, 2017 by Didumos69

[rm8]

Finally, someone decided to stop this "topspeed" infection

[mocbuild101]

Just now, Didumos69 said:

A question I have been playing with since the recent speed topics: Is there any example of a car that can actually shift gears while driving. All motorized vehicles with a gearbox I've seen need to stop to shift to another gear. I wonder if it could be useful in a speed car. Theoretically spoken it should be profitable if you can accelerate with a smaller gear ratio and shift to a bigger gear ratio once at speed.

It should be quite easy to make one, all you would need is a synchronised gearbox - I think...

 

Just now, rm8 said:

Finally, someone decided to stop this "topspeed" infection

Well I wouldn't say stoped - more like tried to organize...

[Aventador2004]

11 minutes ago, Didumos69 said:

A question I have been playing with since the recent speed topics: Is there any example of a car that can actually shift gears while driving? All motorized vehicles with a gearbox I've seen need to stop to shift to another gear. I wonder if it could be useful in a speed car. Theoretically spoken it should be profitable if you can accelerate with a smaller gear ratio and shift to a bigger gear ratio once at speed.

That was because my plan, but I don't have a train motor to test yet.

6 minutes ago, mocbuild101 said:

Well I wouldn't say stoped - more like tried to organize...

The second one, just trying to organize.

[Victor Imaginator]

3 hours ago, Didumos69 said:

A question I have been playing with since the recent speed topics: Is there any example of a car that can actually shift gears while driving? All motorized vehicles with a gearbox I've seen need to stop to shift to another gear. I wonder if it could be useful in a speed car. Theoretically spoken it should be profitable if you can accelerate with a smaller gear ratio and shift to a bigger gear ratio once at speed.

Have you seen my drum/piano gearbox prototype? It's not properly synchronized, but can switch gears without stopping. With some delay between disconnecting one gear and connecting another. But this delay is really small. Almost comparable to real life Porsche's PDK)

[TechnicSummse]

21 hours ago, Aventador2004 said:

Hey @Marxpek, @TechnicSummse, and @mocbuild101, I noticed you all had several conversations running in different topics, it was becoming unreadable. This can be a helpful place to post your stuff, inside this topic. 

Post at will, or ignore, your choice.

Its a nice idea... but im not sure, wich general informations could be stored, and in wich way.

The only things we know so far, are basic physic things... small wheels, lightweigt, flat design.

We cannot list usefull general information for others, since we are learning by doing all the time, and still.

What we can say is... (my opinion ;))

 

- a usefull gearing range could be something between 1,66666 and 3,5(from lowspeed output) (the inner gearing in the motor is 23:17 between low and high output)

- usefull (driven) wheels should be as big as possible, and as small as possible at the same time

- buggy-motors seem to be the only real thing so far (you need a RC-unit to have full power suply, and you need 1 RC-unit for each 2 buggy-motors)

- The speed-limit using 2 motors should be something like 35kph... with 4 motors it could be ~40kp, but we didnt reach this yet :(

 

I think there are no other or more detailled informations.... i would love to create a list with information like: topspeed = xx, weight= yy, gearing=xx

But this will be different for each construciton, depending on bearings, construction-stability, air resistance, the used track, and so on...

But maybe we should do it, and we will find some, until then, not seen information in this data

 

Edited July 7, 2017 by TechnicSummse

[Didumos69]

1 hour ago, Victor Imaginator said:

Have you seen my drum/piano gearbox prototype? It's not properly synchronized, but can switch gears without stopping. With some delay between disconnecting one gear and connecting another. But this delay is really small. Almost comparable to real life Porsche's PDK)

I did now . Cool concept. A nice feature is that is has minimal friction. For a speed model I think 2 speeds should be sufficient. I will try to figure something compact, light and with minimal friction.

[TechnicSummse]

2 minutes ago, Didumos69 said:

I did now . Cool concept. A nice feature is that is has minimal friction. For a speed model I think 2 speeds should be sufficient. I will try to figure something compact, light and with minimal friction.

We talked allready a few times about gearboxes. They wont bring any benefit in topspeed... just shorten the required track. But they will add some weight and a lot of friction. Not just the gears... but especially the additional axles (axle/beam-friction).

You could try this one:

Some time ago, i found this on @Sariel's Website.

This could be a solution, but here is verry verry much axle-beam friction. This could be reworked with some thin beams, and it would be easy to add another pair of motors here.

[Victor Imaginator]

43 minutes ago, Didumos69 said:

I did now . Cool concept. A nice feature is that is has minimal friction. For a speed model I think 2 speeds should be sufficient. I will try to figure something compact, light and with minimal friction.

Hmmm... I think it's possible to make 3 speed gearbox for using with Servo motor. I hope that Servo will provide enough torque to hold hammers in position. I should build it)

[MattL600]

I don't have buggy motors, is it possible to achieve like 20kmh on XL motors?

[mocbuild101]

Just now, MattL600 said:

I don't have buggy motors, is it possible to achieve like 20kmh on XL motors?

Maybe, but I have never tried it...

You would need some very high gearing to get 20km/h.

[TechnicSummse]

1 hour ago, MattL600 said:

I don't have buggy motors, is it possible to achieve like 20kmh on XL motors?

20 should be possible... there is a car wich uses 4 M-Motors geared 40:8 running ~22kmh

 

[MattL600]

3 hours ago, TechnicSummse said:

20 should be possible... there is a car wich uses 4 M-Motors geared 40:8 running ~22kmh

Wow 40:8 for only 22km/h with M motors? 

Dang, I didn't realise how weak Lego motors were

Edited July 8, 2017 by Milan
Please don't quote images or videos from the same page

[Bostons Brick Closet]

This is a great topic, I am trying to build the fastest All Lego, No Motors Car. I want to know if any one else has tried to do this, I would like to know about other peoples top speeds

[Bostons Brick Closet]

Just now, LvdH said:

How will you measure the speed if you're not using any motors? Unless you mean LPE, I don't see any way to drive a car without a motor.

( : -> No

no Pneumatic Either...

I am planning to use Pull back and go motor(s). Have a great weight to speed ratio ( I think???)

Edited July 9, 2017 by Bostons Brick Closet

[mocbuild101]

10 hours ago, Bostons Brick Closet said:

I want to know if any one else has tried to do this, I would like to know about other peoples top speeds

I haven't tried myself, but I do know @Jurss was planing on doing the same thing:

 

[Marxpek]

19 hours ago, Bostons Brick Closet said:

I am planning to use Pull back and go motor(s). Have a great weight to speed ratio ( I think???)

I have been experimenting a bit with these pullbacks earlier, they are fun but do not expect miracles from them, 2 of the newest version can work great with 62mm wheels, but they will have problems with anything larger, they do not have the torque, more motors will get more torque of course, fun project but it has some limitations, but to find the limit within these limitations is another great challenge!

[Bostons Brick Closet]

24 minutes ago, Marxpek said:

I have been experimenting a bit with these pullbacks earlier, they are fun but do not expect miracles from them, 2 of the newest version can work great with 62mm wheels, but they will have problems with anything larger, they do not have the torque, more motors will get more torque of course, fun project but it has some limitations, but to find the limit within these limitations is another great challenge!

I am planning to use the standard large motorcycle wheels and with four I am hoping this will be 4x the torque?? I don't know... but I think it is worth a try ( :

[Marxpek]

Just now, Bostons Brick Closet said:

I don't know... but I think it is worth a try ( :

It is always worth a try, have fun!

[Bostons Brick Closet]

I'll comment on this thread when I have some progress (a few weeks - probably)