MOC need ideas and help please

[Rodeown]

I only made 1 MOC up to now as i only got into lego technic in January this year, i made the Water Jeep for TSATS contest so dont have much experience.

I have some ideas for my second MOC but am struggling to start it as i am not sure what way to do it. Help and ideas would be appreciated.

I would like to make a Truck yes i know not very original but i want to make it slightly different than what i have seen before.

what i want is an UK style Over engine tractor unit similar to the 9397 B model plough truck style but shorter, with articulated trailer

utilising my trailer rear steer system, i also want it to be a tipping trailer but all remotely operated... now this is where i have a stumbling block.

How do i power the trailer systems, do i make it so once connected i connect a power cable to the truck cab to power trailer motors,

or do i make a drive shaft connection system that transfers power through a universal joint to the trailer or through the connecting pin,

or do i make both the cab and the trailer with thier own battery box and ir reciever to power them?????

also as regards to the Cab/tractor unit what is the best remote steering system, NXT or PF and if return to center then it wont be as

accurate as non return to center, and how do i make it with out stressing the pf motors?

Any suggestions help or just plain ideas would be appreciated.

sets i am working with:-

1 NXT 2.0 set

1 9397 logging truck set

1 8109 Flatbed Truck

1 8110 unimog

1 8043 Motorized Excavator (keeping second one complete)

and 4 extra wheels for the 9397 log truck.

Edited April 24, 2012 by Rodeown

[vmln8r]

I believe that some of these things you'll just have to try out for yourself, and that direct solutions won't help in the long run. That said, looking at these creations might help. A good place to start is with the most difficult bit - it sounds like powering the trailer in your case. I haven't heard of RTC steering damaging anyone's motors.

[Alasdair Ryan]

What you want to do is ,build the logging truck B model and use it as the tractor unit,motorizing this is not very hard ( i have not done it) use one of the 8043 receivers and 2 pf motors for drive and the steering. You should be able to gear down a pf small motor,but would be better if you had a xl motor for the drive use one of you battery box to power this half (put it in the cab).

Then you could use the other receivers for the trailer(tip body,rasie/lower legs) it would be best if you could have a separate battery box in the trailer.

[chorlton]

I asked a similar question about stressing the motors for RTC steering in another thread. In the end I've just gone ahead and tried it. It seems OK for a fast buggy where it tends to 'jink' and be in the right direction very quickly. If you are trying to position a truck however, particularly if you fancied reversing with an articulated trailer, then I could imagine you spending a lot more time at full lock, and so straining the motor for longer periods. A clutch gear would prevent this but you'd need to ensure your RTC spring mechanism wasn't too strong.

For powering the trailer - a real trailer would be hooked up to a power and hydraulics feed from the tractor unit - so a battery box in the tractor with motor in the trailer, hooked up when connected would be the most 'authentic'

Edited April 24, 2012 by chorlton

[Rodeown]

That said, looking at these creations might help. A good place to start is with the most difficult bit

Thanks for that link VMLN8R, some good trucks there and yes start with the most difficult bit sounds like a good idea

What you want to do is ,build the logging truck B model and use it as the tractor unit,motorizing this is not very hard

Then you could use the other receivers for the trailer(tip body,rasie/lower legs) it would be best if you could have a separate battery box in the trailer.

Thanks Alasdair, the trouble with the 9397 B model is that it is too long for a tractor unit like we have in the uk so i will make one from scratch i think, much more satisfying that way anyhow. and the tip body/ raise lower legs is important like you say, i was even thinking of a system for connecting to the trailer without manual input, some sort of trailer lock mech like on real trucks that locks in place as you reverse into the trailer, would be a challenge but not impossible i think.

If you are trying to position a truck however, particularly if you fancied reversing with an articulated trailer, then I could imagine you spending a lot more time at full lock, and so straining the motor for longer periods. A clutch gear would prevent this but you'd need to ensure your RTC spring mechanism wasn't too strong.

For powering the trailer - a real trailer would be hooked up to a power and hydraulics feed from the tractor unit - so a battery box in the tractor with motor in the trailer, hooked up when connected would be the most 'authentic'

Chorlton, my thoughts exactly on reversing, that is why i thought maybe NXT steering would be better with a return to center command so that when not been issued commands it would stay where i put it or return to center if i told it too, we dont have return to center in real vehicles ! this would have to be controlled by my android tablet so may get complicated, i will look into it.

also the cable connected when hooked to trailer does sound authentic aswell, great ideas guys much appreciated.

[Alasdair Ryan]

Lasse D has made trailer hiches that work like that,check out his web site for more info Classic Model Team.

[Rodeown]

OK i have been very ill this last weekbut had some time to start my project but i have now hit a problem requiring advice if possible please.

I have made a (IMO) very good almost "ackerman" steering for the truck that works slow enough to be realistic and precise but also accurate for steering etc

but the problem i now have is to the drive of the truck, I am using medium motors not xl and this is not an issue as they will be geared slow as i am not building a race truck so i decided a simple gear system would be required, fast for normal driving around and snail crawl for reversing with trailer and tight manouvers, whilst its easy to make this manually using the usual lego methods my son told me to make it so i could motorise the change over from slow to fast by remote.... this is when i encountered a problem, the red selector is only 2 holes wide so the selector lever is positioned half way between two holes? i tried allsorts of ways to get a motor mounted to operate it but keep getting it jumping out of the slot etc, if i move it half a hole it works one way but comes out the other way so it has to be central, i have tried to find videos etc of how others have done it all to no avail.

anyone had a similar problem as i have spent so many hours finding all the ways NOT to do it now i am going bald from the hair pulling

[DLuders]

@ Rodeown: Are you talking about something like Halhi 141 did on MOCpages?

[dhc6twinotter]

this is when i encountered a problem, the red selector is only 2 holes wide so the selector lever is positioned half way between two holes? i tried allsorts of ways to get a motor mounted to operate it but keep getting it jumping out of the slot etc, if i move it half a hole it works one way but comes out the other way so it has to be central, i have tried to find videos etc of how others have done it all to no avail.

anyone had a similar problem as i have spent so many hours finding all the ways NOT to do it now i am going bald from the hair pulling

Getting that 1/2 stud offset can be a bit tricky sometimes. There are several different ways to accomplish this:

1) Place a 1/2 beam or 1/2 bushing behind the clutch gears. This allows the clutch gears and driving ring to be off by 1/2 stud instead of the selector lever. If you have the space, this is probably the easiest way to build a gearbox. The 8265 front loader uses a gearbox design like this, and this is how I built the gearbox on my float plane.

2) The Unimog uses the part below mounted sideways to get that half offset on the selector lever:

The log truck and, iirc, the flat bed truck use a similar method for the half offset.

3) Paul (Crowkillers) uses the following part to get the 1/2 lever offset on his transmissions:

4) I have used the following method to get the 1/2 offset on both my forwarder and backhoe:

I used 3 of these parts per side, separated by 1/2 bushing:

Also, notice how I have 1x5 dark bley beam there also. If you placed a beam on either side of the gearbox like that, it would help keep the selector lever from jumping out of the driving ring.

I don't particularly like this gearbox design, but it works. It's just not a very elegant solution, imho. I'll probably try to come up with something better on my future projects.

Anyways, hope that helps.

Edited May 6, 2012 by dhc6twinotter

[Rodeown]

@ Rodeown: Are you talking about something like Halhi 141 did on MOCpages?

NOPE! I will have to do some pictures or a vid when i am up to it, I am also making it as flat as possible knowing that this truck is limited on space because of trailer and short wheel base with only 4 wheels.

4) I have used the following method to get the 1/2 offset on both my forwarder and backhoe:

Awesome, thanks for all the advice, plenty for me to work with there, great idea with the 3 pieces and spacers, i had tried using the same method as on the motorised ecavator but it moves around too much for what i am attempting but your ideas have given me some inspiration.

Also what is the best way of motorising the change over as i am concerned about stressoverloading the motors as that will kill battery life and motor life, took me 3 days to work out a suitable steering system for my truck until i was happy with what i designed, must have made about twenty different setups before going the route i did eventually. I do try to solve the problem myself first then go look at other peoples ideas when i get stuck because you may just stumble on something new whilst testing. Thanks again guys.

[dhc6twinotter]

Also what is the best way of motorising the change over as i am concerned about stressoverloading the motors as that will kill battery life and motor life, took me 3 days to work out a suitable steering system for my truck until i was happy with what i designed, must have made about twenty different setups before going the route i did eventually. I do try to solve the problem myself first then go look at other peoples ideas when i get stuck because you may just stumble on something new whilst testing. Thanks again guys.

I usually use a white 24t clutch gear to keep the motor from stalling. However, if you are using the smooth axle connectors inside your driving ring, the driving ring can slip out of your 16t gears under high-torque applications. I solve this by using a worm gear to move the driving rings, as seen in my picture above. Put the white 24t clutch gear on the axle that turns the worm gear, with the worm gear turning either an 8t or 24t gear that is connected to the selector.

I hope that makes sense. I'm not very good at explaining stuff.

[Lipko]

Take a look at how supercars use those red thingies. They are placed right between 2 beams, like this, so they can't pop out of the rings:

Maybe I misunderstood, and that's not the issue...

Maybe you just have to reinforce the structure. Try to use the shortest axles if possible, shortest distances between two beams, etc.

Edited May 7, 2012 by Lipko

[Rodeown]

I usually use a white 24t clutch gear to keep the motor from stalling. However, if you are using the smooth axle connectors inside your driving ring, the driving ring can slip out of your 16t gears under high-torque applications. I solve this by using a worm gear to move the driving rings, as seen in my picture above. Put the white 24t clutch gear on the axle that turns the worm gear, with the worm gear turning either an 8t or 24t gear that is connected to the selector.

I hope that makes sense. I'm not very good at explaining stuff.

Makes Perfect sense Thanks DHC6twinotter and Lipko yes that is the correct thing the problem is getting the beams offset half a hole to line up with the red selector lever,it is possible but not solid but I have many ideas now thank you all and will get back later with some pics/video maybe, see how i am feeling.