42080 Forest Harvester

[allanp]

Could it be that the pump is geared up, or that there are multiple pumps to improve performance (as opposed to the usual single pump) and that's why there's an L motor? 

[Omikron]

Just now, allanp said:

Could it be that the pump is geared up, or that there are multiple pumps to improve performance (as opposed to the usual single pump) and that's why there's an L motor? 

Pump is not something very demanding on such motor, besides you can always gear up or gear down. In this case M-motor would be sufficient. I think that it has something to do with new valves. I can only see 1 pump.

Edited May 30, 2018 by Omikron

[Ngoc Nguyen]

The curious thing is that the battery box is limited to one way only. The battery box in 42053 is also limited the same way. Meanwhile, earlier sets with motorized pumps (8110, 42008, 42043) doesn't have this feature. I still don't understand why one rotation direction is preferable (or less) than the other.

[Maaboo the Witch]

10 minutes ago, Ngoc Nguyen said:

The curious thing is that the battery box is limited to one way only. The battery box in 42053 is also limited the same way. Meanwhile, earlier sets with motorized pumps (8110, 42008, 42043) doesn't have this feature. I still don't understand why one rotation direction is preferable (or less) than the other.

Someone (can't remember who) recently said that reversing the direction of the pump on 42043 made a noise like beams being batted together, which doesn't sound healthy. I think that's why TLG restricted it from then on.

[Ngoc Nguyen]

Just now, Maaboo35 said:

Someone (can't remember who) recently said that reversing the direction of the pump on 42043 made a noise like beams being batted together, which doesn't sound healthy. I think that's why TLG restricted it from then on.

But how did that happen? It's still the same movement sequence (expansion and compression) is it not

[Maaboo the Witch]

1 minute ago, Ngoc Nguyen said:

But how did that happen? It's still the same movement sequence (expansion and compression) is it not

No idea, you'd have to ask whomever posted that information, and I can't remember who it was.

Edited May 30, 2018 by Maaboo35

[Omikron]

Lego motors work good only if they rotate clockwise. If you switch the direction they behave differently, they start to jerk and struggle so to speak, one example would be - a car can move forward but if you try to switch rotation direction of the motor - it won't move. It either caused by internal gearing or by how the electrics are made. There was an article about this couple of years ago, but I can't find it at the moment.

Edited May 30, 2018 by Omikron

[allanp]

I don't see how the new valves could require an L motor, or how they could be related as the old valve has the ability to go from fully open to fully closed and everywhere in between. What other state could the new valve have that would require the use of a more powerful motor?. But if there are 4 pumps, or if a single pump is geared up 3:1 for example, then the use on an L motor becomes more understandable. A motor pump can generate in excess of 60psi if the seals are good, a pump with that kind of load on it, if you have many of them or if it is geared up can require a fair amount of torque.

I remember doing some tests and found that the hose connected to the pump can in some cases torque the pump over to favour one side. Like if you were to disconnect the pump from the crank end the hose would raise or lower that end depending on weather the hose is pushing or pulling on it, depending on how the hose is bent round to fit onto the pump. This has the effect of a small bending force being applied to the pump, which is severe cases can greatly affect the effectiveness of the seals. As the hose will cause more or less bending of the pump depending on where the crank is it is best to have the compression stroke be on the side of the crank where the hose is causing the least amount of bending of the pump. This appeared to be why the pump worked more effectively when the motor turned one way and not the other.

Edit @Omikron I didn't know that about the motors only working well in one direction. Will have to find that article.

Edited May 30, 2018 by allanp

[Ivan_M]

I wouldn't be looking for a reason to use L motor in the model, but somewhere in TLG account books/warehouse stock/ suppliers possibilities. The reason might by that they have overstock of L motors or something like that. The price difference for TLG between M and L have to be less than 1€.

[Omikron]

You can literally take any motor and plug it in the AA battery box, preferably with old batteries (not rechargeable). Not only you will hear the difference, but you will also see it.

[andythenorth]

42 minutes ago, Omikron said:

It either caused by internal gearing or by how the electrics are made. There was an article about this couple of years ago, but I can't find it at the moment.

I can believe this could be true, but I've never seen any evidence of it at all.  Seems like FUD to me tbh.   Happy to be proven wrong.

Re: pumps and L motors, to get decent performance out of pneumatics demands more flow than I've seen any official TLG motorised pump produce.  Motorised compressors in official TLG sets are a waste of space and parts; they're great for marketing, but are negative for play value.  .  Replacing them with a hand pump is always an improvement.

This goes right back to motorising the hand pump in the 8851 red excavator, and is still useless in the Arocs ~30 years later.  [whining over] 

Edited May 30, 2018 by andythenorth

[model850]

I'm arriving late to the discussion but I guess they've opted for the L motor because of the double (large) cilinder configuration that lifts the log. Those cylinders have large volume that needs to be filled quickly in order to have decent lifting speed, at least judgeing by this video https://tinyurl.com/ybwk5ntb where small pump and M motor supply one cylinder at the time.  Or maybe it has something to do with the B model where they need additional power.

 

Edited May 30, 2018 by model850

[Omikron]

Just now, model850 said:

I'm arriving late to the discussion but I guess they've opted for the L motor because of the double (large) cilinder configuration that lifts the log. Those cylinders have large volume that needs to be filled quickly in order to have decent lifting speed, at least judgeing by this video https://tinyurl.com/ybwk5ntb where small pump and M motor supply one cylinder at the time.  Or maybe it has to do with B model where they need additional power.

 

But one pump + 2 cylinders is not stressing load even for an M-motor which you can gear up for the task. L-motor has less RPM than an M-motor.

[agrof]

M motor and L motor has only 15 rpm difference, which is barely noticable. Don't forget, that here it should run pneumatic pump with some friction and resistance due to pneumatic pressure, so torque is more relevant, where L motor easily the better choice (18Ncm vs 11 Ncm). Not to mention, IF this machine uses 2 pumps for faster operation... I am skeptical with this, but could be an option.

[Lipko]

Um... Maybe the reason is that the L motor has much better interface than the M-motor*? I see no reason to use M motor unless the space is very tight and 1 stud matters. Or is the price difference between the M and the L so great that the usage of L motors is to be avoided if possible?**

*An M motor can easily drive via 12/20 reduction two pumps with closed circuits and the safety valves engaging. The reason is that the pumps operated in opposite directions, so 2 pumps are really 1 pump providing system pressure and 1 pump sucking in air, which is not a significant load. I see no reason in this model to have more pumps.

**edit: okay, the price is almost the double. Maybe Lego just wants to get rid of the M motor, which is indeed a bit out of the Technic system.

Edited May 30, 2018 by Lipko

[model850]

57 minutes ago, Omikron said:

But one pump + 2 cylinders is not stressing load even for an M-motor which you can gear up for the task. L-motor has less RPM than an M-motor.

 

I guess you're right since I haven't tested that option. Lower RPM certainly make this case even stranger. Maybe space constraints in the back part do not allow for the gearing mechanism to be placed or stronger motor is required for the 3rd power function which I can't figure out. 

 

31 minutes ago, Lipko said:

*An M motor can easily drive via 12/20 reduction two pumps with closed circuits and the safety valves engaging. The reason is that the pumps operated in opposite directions, so 2 pumps are really 1 pump providing system pressure and 1 pump sucking in air, which is not a significant load. I see no reason in this model to have more pumps.

 

I think the real question is which of the following options has the best cost/benefit:

1) 1 pump + 1 M motor = cheapest  /  lowest speed  /  smallest space consuption in the back cabin

b) 1 pump + 1 M motor + gearing up mechanism = cheap  /  sufficient speed  /  modest space consumption

c) 2 pumps + M motor = expensive  /  sufficient speed  /  significant space consumption 

d) 1 pump + L motor = maybe cheaper than option "c"  / performance unknown  /  small space consumption

e) L motor is needed for B model or 3rd power function

Edited May 30, 2018 by model850
Inserting more information.

[agrof]

Yeppp, we might overthink this. L-motor has way better intgration ability due its connection points, and that's it.

[Ngoc Nguyen]

M motor doesn't have that many holes probably because it doesn't vibrate as much. In many sets the M motor is connected only through the front holes, while the rear holes is left hanging (in 9397).

[agrof]

Isn't it the opposite? M motor is connected only through front holes, because it has those connection points only (not considering anti-stud face underneath)? 

L motor is easier to install, and can be active part in structural strength, so for me no question which I would pick first (L).

Edited May 30, 2018 by agrof

[Ivan_M]

1 hour ago, Lipko said:

**edit: okay, the price is almost the double. Maybe Lego just wants to get rid of the M motor, which is indeed a bit out of the Technic system.

You cannot compare them by retail or aftermarket price. When you produce such motors in huge quantities price is VERY low, I would say internals of both motors are below 1,5€, casing is nearly the same in terms of manufacturing costs.

L motor is indeed better for pump operation due to its better mounting points, one pump is usually causing a lot of vibration due to its cyclic motion

[Maaboo the Witch]

Looking closely at the set image, there is a long towball joint running from near the articulation point to the front axle, so it looks like the central pivot point works in tandem with the axle for better steering.

Edited May 31, 2018 by Maaboo35

[Maaboo the Witch]

Just noticed something: the catalogue image shows that the top half of the log being sliced has a yellow axle in the centre. Can this log only be sawn off in one place? If so, that's stupid. 

[Ngoc Nguyen]

1 hour ago, Maaboo35 said:

Just noticed something: the catalogue image shows that the top half of the log being sliced has a yellow axle in the centre. Can this log only be sawn off in one place? If so, that's stupid. 

Duh, of course those log bricks need a central axle. Otherwise they are prone to breaking apart and can't be picked up as one log piece.

Edited June 3, 2018 by Ngoc Nguyen

[allanp]

Yeah, I expected there to be axles in the logs. Simply leaving the axles out has to be the easiest mod ever. 

[abrahamandentity]

This is the kind of set people would use as a piece farm...

I’d disassemble it just for the pneumatics .