So, I designed it, spent 200 or so AUD to get all the pats, and sadly it doesn't work, for a wide variety of reasons.

Mostly, the power functions parts are too heavy, and the XL motor is too weak. Also, the speed controler does not allow the fine inputs required to steer a motorcycle, nor does it have much range.

In the near future I will try to design a bike around the RC buggy parts. With they're radio control and lighter weight, I hope for more success.

This bike is sitting on my shelf, 90% complete, so I will just show you these LDD screens. I don't have a camera, either!

I'm not sure whether using the Lego RC components will work on something that small. I see that you're using the Power Functions Servo Motor for steering. To save weight, you should consider using a 99499c01 Power Functions L-Motor (in place of the PF XL motor) and a 8878 Power Functions Rechargeable Battery Box (which has an added benefit of being smaller than the regular PF Battery Box). Your PF Receiver may be too shielded by other parts to get a strong signal from the PF Controller.

Is it the fact that the xl motor has to move it quickly for it to balance? If so then yeah none of the pf gear will do a better job, two large motors is your best bet but they are still not ideal. Buggy motors are awesome two will definatly move it quickly but the receiver might prove hard to hide...

You look like you know what your doing by the quality of your design so im sure you have thought through all the posibilities.

In addition to being heavier than your current setup, the RC system is obviously not modular, which doesn't lend itself to flexibility and a compact design. I'd imagine it will result in a larger chassis than what you already have. Also, it's steering motor only has three steps.

How have you been getting this thing to balance? Zblj and I have both built PF bikes*; I believe his used the steering and a wide rear wheel for balance, while mine had very low centres of gravity.

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I'd lower the center of gravity and slacken the head angle for stability.

Speed won't gain you a lot of stability, there's not enough mass in the wheels to have a meaningful effect.

I'm not sure whether using the Lego RC components will work on something that small. I see that you're using the Power Functions Servo Motor for steering. To save weight, you should consider using a 99499c01 Power Functions L-Motor (in place of the PF XL motor) and a 8878 Power Functions Rechargeable Battery Box (which has an added benefit of being smaller than the regular PF Battery Box). Your PF Receiver may be too shielded by other parts to get a strong signal from the PF Controller.

The rechargable battery box has no technic mounting points, so all the additional bracing required to use it would negate the effects of the weight saving. It also has lower voltage, and the XL motor at 9v isn't powerful enough. Speed is one key to keeping an RC bike without a flywheel upright.

Speakling of flywheels, I wonder if there are any steel lego train wheels...

You look like you know what your doing by the quality of your design

Thank you!

In addition to being heavier than your current setup, the RC system is obviously not modular, which doesn't lend itself to flexibility and a compact design. I'd imagine it will result in a larger chassis than what you already have. Also, it's steering motor only has three steps.

How have you been getting this thing to balance? Zblj and I have both built PF bikes*; I believe his used the steering and a wide rear wheel for balance, while mine had very low centres of gravity.

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The buggy chassis/reciever/battery unit has a few pinholes, that's all I need.

As for it's steering having only 3 steps, thank you for sharing that fact. I was going to have to ask around about it's steering! I'm dissapointed it doesn't have a servo steering motor.

I believe the keys to RC motorcycle balance are good speed combined with negative trail on the front forks, and the ability to finely control the steering.

Of all of the power functions bikes I have seen (I have searched high and low, I will post a funny russian one when I find it agian) none have truly leaned like a motorcycle.

I do like your Octan Sportsbike, because I love Octan! What a wonderful old-school colour scheme

EDIT: I just found these

http://www.bricklink.com/catalogItem.asp?P=70163

If I am not mistaken they are steel. Six/12/18 of them mounted around a technic pully wheel would make a nice heavy flywheel. they are 11 grams each, just six would weigh as much as a PF XL motor!

Edited December 17, 201212 yr by Kierna

As for it's steering having only 3 steps, thank you for sharing that fact. I was going to have to ask around about it's steering! I'm dissapointed it doesn't have a servo steering motor.

But it does! Look for it in the forums, I remember an extensive review from Philo about it.

RC is heavy and big.

I think the only was is:

Edited December 17, 201212 yr by rm8

RC is heavy and big.

I think the only was is:

BLASPHEMY!

Training wheels are the enemy! If a bike has them, it is not a bike, it is a car with two wheels that are smaller.

However, I have been pondering, is a steamroller technicaly a motorcycle? Two "wheels", right?

I found this EB thread

http://www.eurobricks.com/forum/index.php?showtopic=71623&hl=supersonic#entry1328868

In it are lots of helpful facts, and very good news! The RC buggy reciever unit has a steering servo built in, as an axle hole at it's front. The steering control has 3 positions in each direction, and is said to rotate 30 degrees either way from vertical. That means 10 degree rotations on the steering output! That is finer control than the PF servo motor with PF speed controller, which has 12.5 degree rotations.

So. The next recipe for an RC Superbike is:

RC buggy reciever unit with one or two buggy motors

Presice, adjustable, steering, with light RTC. perhaps two extra soft shock absorbers.

A heavy flywheel.

I need the dimentions of the buggy reciever unit, and the buggy motor.

If anyone who has them would be so kind as to take a photo of them from every angle with some long liftarms for scaling, I would be very grateful and much obliged

Clarkdef, thank you very much!

Do you happen to also have the reciever unit / battery box?

The rechargable battery box has no technic mounting points, so all the additional bracing required to use it would negate the effects of the weight saving. It also has lower voltage, and the XL motor at 9v isn't powerful enough.

You could put 6 ea. 1.5V AAA Alkaline batteries in the 88000 "Power Functions AAA Battery Box" if you're worried about the voltage. The AAA batteries don't last as long as AAs, but they are perfectly adequate for play. You could attach some 2444 "Plate, Modified 2 x 2 with Pin Hole" parts to the underside of the battery box to attach it to the Technic pinholes in your frame.

Trail provides stability because it allows for self correction. Fixing a motor directly to the steering without any play in the mechanism removes this ability to self correct. Think of a riderless bike, even at slowish speed it doesn't need external steering inputs to obtain stability because the geometry is self correcting.

Essentially, I think you need to dampen the steering inputs and allow the geometry of the bike to work to your advantage.

I would also watch the effect that the torque of a laterally positioned steering motor may have - when the servo was mounted high up, this could have caused a few negative issues.

The rechargable battery box has no technic mounting points, so all the additional bracing required to use it would negate the effects of the weight saving. It also has lower voltage, and the XL motor at 9v isn't powerful enough.

Not to argue, but depending on which batteries you're using, the 8878 rechargeable battery can weight 3 times less than the battery box (it's 75 grams while my battery box weights 235 grams). So you can easily save 150 grams or more, and all the bracing you need are four 1x2 Technic bricks with a hole that you put on top and bottom of the 8878 on two sides, to mount it on pins.

Also, the voltage does not affect the motor as much as most people think. The torque remains the same for any voltage, only speed changes. And while you do get a higher speed out of 9V batteries, they will deteriorate quickly - depending on the brand - and old batteries can easily drop under 7V. The 8878, on the other hand, provides fairly steady voltage until it's completely dry.

I need the dimentions of the buggy reciever unit

It's monstrously big. Quite possibly larger than your whole bike. It's also very wide and you'll have a lot of difficulty to balance it out in any other position than horizontal.

Personally, I think that with Technic, it works best to design with the pieces you have at hand and to test your creation while building it. Computer design works well for castles and such, but it's full of traps for Technic.

Edited December 17, 201212 yr by Sariel

That is a really nice looking project.

Clarkdef, thank you very much!

Do you happen to also have the reciever unit / battery box?

No sorry. I just bought one on bricklink, should take all of a month to get to me lol. Im building a dirt hillclimb vehicle and I need something to climb a section of a mountain, so I need distance of the RC stuff, hopefully it works properly... I think it will be too big for your realistic street bike, however I feel you can exacerbate the look to be a bottom heavy wide body beast, maybe a hillclimb freak of a bike ;) with a power puller wheel at the back!!!

Edited December 17, 201212 yr by clarkdef

Here are the instructions for one of the RC buggies, you can see how huge the battery/steering unit is.

http://cache.lego.com/bigdownloads/buildinginstructions/4181789.pdf

Not to argue, but depending on which batteries you're using, the 8878 rechargeable battery can weight 3 times less than the battery box (it's 75 grams while my battery box weights 235 grams).

The RC reciever unit is monstrously big. Quite possibly larger than your whole bike. It's also very wide and you'll have a lot of difficulty to balance it out in any other position than horizontal.

Personally, I think that with Technic, it works best to design with the pieces you have at hand and to test your creation while building it. Computer design works well for castles and such, but it's full of traps for Technic.

I didn't know it was so much lighter! That would indeed substantialy lighten my load, however, IR recievers are still no good for fun in the sun!

The RC stuff is my only hope now.

I'm not sure of the exact dimentions of the RC unit, but I think it would fit between the wheels of a bike with a similar wheelbase. I don't need to use the external rack and pinion steering unit.

I think, maybe, that the RC reciever unit has a simmilar volume to PF batterybox + reciever + servo motor. And after looking at the bricklink item weights, it weighs just 50g more than those items combined. I'm about to study a supersonic RC instruction and try to guage it's exact dimentions.

However, Sariel, if you could find the time to photograph an RC reciever unit from all angles, it would be much appreciated. I will give you credit if I manage to make this madness work

Also, do you know of any equasions to determine how heavy a spinning gyroscope needs to be to stabilize something of a given weight?

That is a really nice looking project.

Thank you very much

No sorry. I just bought one on bricklink, should take all of a month to get to me lol. Im building a dirt hillclimb vehicle and I need something to climb a section of a mountain, so I need distance of the RC stuff, hopefully it works properly... I think it will be too big for your realistic street bike, however I feel you can exacerbate the look to be a bottom heavy wide body beast, maybe a hillclimb freak of a bike ;) with a power puller wheel at the back!!!

I like your thinking It will be a streetbike, not a hillclimber though. Definately a freaky beastie! Because I know anything with RC components won't pass cuusoo review, I can make it into the streetfighter I want it to be... I made the superbike in general good taste.

Lower part will look like a honda goildwing or bmw boxer, because of the rc unit hanging out the sides:

With a big slice of this:

@ Kierna: Look at the huge number of studs taken up by the Lego RC Receiver unit:

@ Kierna: Look at the huge number of studs taken up by the Lego RC Receiver unit:

That is not the RC reciever unit I was reffering to, but the much larger unit from the "racers" i believe, the "dirt crusher" and such. It weighs 388 grams, according to bricklink.

This is the one I wish to use, from the Supersonic Rc / Rc Race buggy. A much more acceptable 171 grams. It has the steering motor built in, with an axle hole at the front for output. EDIT: And many usefull pin holes for building around. It's steering motor, I am led yo believe, has finer control than the powerfunctions servo motor.

Edited December 20, 201212 yr by Kierna

I looked into those rechargeable lego batteries, but then when I saw the price I looked away haha. Also the thing is with em or the other battery boxes is that they can only power one buggy motor, any more buggy motors and the power functions circuits kick in and stop the fun.

I think your plan is good, just make sure that you order a well test module as they can have problems, most being used and REALLY abused

This is the one I wish to use, from the Supersonic Rc / Rc Race buggy.

Mister, this thing is 13 studs wide and the weight of 171 grams doesn't include batteries. In total, it's heavy as a brick and similar to one in size. I own this thing, and I'm telling you, you could just as well try to fit an elephant in a motorbike. Just look:

Also, do you know of any equasions to determine how heavy a spinning gyroscope needs to be to stabilize something of a given weight?

You can't stabilize a bike with a gyro directly, I know, I tried. Gyro's don't work that way, you can't attach them to something to make it stable. See how a Segway works - it monitors the position of a gyro electronically, and adjusts its own position respectively using a complex software and a number of motors.

You could stabilize a bike using NXT and electronic gyro. Costly, but possible. Example here:

Edited December 20, 201212 yr by Sariel

Mister, this thing is 13 studs wide and the weight of 171 grams doesn't include batteries. In total, it's heavy as a brick and similar to one in size. I own this thing, and I'm telling you, you could just as well try to fit an elephant in a motorbike.

You can't stabilize a bike with a gyro directly, I know, I tried. Gyro's don't work that way, you can't attach them to something to make it stable. See how a Segway works - it monitors the position of a gyro electronically, and adjusts its own position respectively using a complex software and a number of motors.

Aren't you the negative nancy I bet people said similar things to Eric Buell when he said "I'm going to build a 180kg motorcycle around that Harley motor."

13 studs width with the 12 stud diameter streetbike wheels puts it spot on with the proportions of that honda goldwing posted above.

171 grams is about 50 more than PF IR reciever, servo and AA battery box combined.

Not to mention the weight will be much lower down, with all the batteries at the bottom.

Furthermore, the unit is just 13 or 14 studs long, meaning it would fit between the wheels of my superbike. It will of course be a few studs longer with front and rear suspension.

Don't forget just how big the streetbike wheels are, 12 studs total diameter, 3 wide with the front tyre and 4 wide on the back.

As for the Gyro's, I was rather mistaken, as I meant to ask the question about "flywheels".

Aren't you the negative nancy I bet people said similar things to Eric Buell when he said "I'm going to build a 180kg motorcycle around that Harley motor."

Sariel is a master creator, and if you were to listen to anyone it should be him. However to make different funiture you should sometimes go against the grain. I really like the idea of bikes, but was never able to build them to work as powered vehicles cause they just fall over. Oh btw didn't know that the RC receiver had a build in servo, kinda made my day :D

I'm not trying to be negative, just trying to spare you time and money spent on another bike that has no means of balancing out and whose proportions are blown by the RC unit. But then, you're the master of your time and money.

I have once spent a while trying to fit as much mechanics as possible into an average-sized motorbike model, and this is what I got. Full suspension, propulsion, lights and all of it closed inside the body, but no means of steering because of the lack of space. I'd say I have a good idea of what can and can't fit in a reasonably sized model.

Edited December 20, 201212 yr by Sariel