Week TechVideo, 2009 #48 - Heavy Duty Differential (HDD)

This week, the most recent experiment by sunsky (Jaeho Jung).
An Heavy Duty Differential (HDD), working like any other off-the-shelf LEGO differential, but made from large and discrete Technic parts.

12-tooth gears are used inside LEGO Technic differentials, which may not resist to high torque applications. These gears may easily break-down under load conditions, e.g. when XL motors are directly applied to them, at full power and something blocks the differential body.

This setup doesn't use any thin and fragile elements, which makes it a lot more resistant to load applications. Perhaps very large scale vehicles or high speed concept buggies, could benefit from such a large diff.

In this setup it is used the top side (or ouside) part, from a disassembled Large Technic Turntable, Type 2.

You may find additional photos at sunsky Flickr stream, but guess is already doing something where to apply this.


Interesting experimental setup!


Edit:
Sunsky made afterwards some modifications to his HDD, trying to achive also something similar to a Limited Slip Differential (LSD) [1].
The first attempt however, had some undesired wearing effects at some parts, which were reduced at the 2nd design. This last one may also have adjustable friction if adding a second of those white 1x3 thin liftarms.

Take a look at these, on the photos below.

.
Almost at the same time there was another HDD being developed. This one by Alex Zorko (nicjasno), for his Mustang.
Bellow some of his pictures.

You may find a lot more, directly from Alex's website (www.nicjasno.com).

I found it really brilliant the usage of such old  red g9 gears used in Gears Sets from my youth (ya, I'm getting old...) into the transmission attached to this differential, as one solution to increase its robustness for high torque and load stress situations.



Last Update: 2009.Dec.06 02:04 CET

8258 - Modification instructions by Han

Certainly you remember some creations from Han, that were shown here at TBs before.

Recently he has been working on some modifications to this year Technic flagship, the 8258 (Crane Truck).
A very nice model with magnificent construction details on its own, but according to Han there are some possible and easy to apply improvements.



The first modification package consists of 8 small changes.

These were classified by his author in three categories:

1. CRITICAL: many customers noticed that the original set sometimes 'crunches'  the 12th tooth bevel gear nearby the XL motor drive-shaft. This can be solved by applying ALL these critical modifications.
   - Add 24th tooth clutch-gear on 1st crane arm section.
   - Relocation of the 24th tooth clutch-gear of the 2nd crane arm section.
   - Prevent ‘walking axles’ for each 12th tooth bevel gear within each PF-LA bracket.
   
   
2. IMPROVED PLAYABILITY: modifications who will contribute to a more effective usage of the technic functions.
   - Reverse movement of the outriggers; to avoid a motor direction switch.
   - Extra clarification to assure precisely ‘in-line’ steering of 1st and 2nd wheels.
   - Correction of lifting eye of extendable crane arm.
   
   
3. APPEARANCE: only 'cosmetic' modifications.
   - Correction of last wheel axle length.
   - Apply short axles (3L) to the steered wheels.
   

All these are functional or 'cosmetic' modifications, perfectly integrated with the model, while not entering into details that would definitely change the original look from this truck.


Included with the second modification package you may find instructions (in 41 steps), to apply so-called 'Twin Wheels' on the rear axles (3rd and 4th axle).

These are added without compromising the rear functional outriggers and also make a very good addition to the original.
 
You may find all these and some more modifications to other official Technic sets from TLG, at Han's website here.

Maybe you would be also interested to know, how does Han creates his stunning building instructions and take a read here.


Test them yourself and tells us about your opinion!

Week TechVideo, 2009 #47 - An automatic gearbox (Ads must be paid...)

Long time ago we at TBs realized on a BS folder where Zblj (Jernej member of Kocke Klub, the Slovenian LUG) had photos from his Tatra 8x8 Trial Truck, taped with the URLs from some LEGO related websites (mostly well known ones).

It was with a big surprise and satisfaction that we saw also the TBs URL there.

Because ads have to be paid... , since then I had it also on my slow post queue and have been looking for something special from Jernej to highlight here.

Today I've decided for his attempt to build an LEGO automatic gearbox. It is not the first time we write here about automatic gearboxes [1], but this one uses a different principle. In fact it looks more like a CVT system (Continuous Variable Transmission), despite its narrow sensitive margin as it seems to switch quite fast.
It is a simple automatic gearbox design, using 2 differentials and a couple of gears.

Based on Jernej explanation here it goes how it functions, in simple words.
Differentials always slips to the easiest side. The left side has friction and the right doesn't. This means the power normally goes to the right. But when the load becomes higher than friction on left side, the power is sent to left side, where there is a higher gear ratio.
Total gear ratio varies between 1:1 and 5:1 (the ratio between the gears on the left side).

You will find it at this BS folder.


A good demonstration for the used principle, rests to know whether it can shows effective at up/down-shifts, into a real Technic vehicle or not.

TechnicBRICKs got LEGO Ads

Sooner or later it should happen... and yes, TBs already started to represent still a small expense to maintain.
One domain for midterm plans, an hosting service to store post images that otherwise tend to become unavailable after some time, mail accounts for whatever is needed like the latest contest and prizes shipping.

For awhile I've seen some LEGO ads, at some other LEGO related blogs and always wondered how to setup them. After some inconclusive investigation, finally decided to ask the help from who knows, et voilà!...
Hope it doesn't bother you too much.


I would say my primary interest is not for any eventual income, which I'm sure will be very, very small if any, but found it a lot of fun to have such genuine LEGO ads and images in our blog.

Nevertheless and from now on, you are welcome to initiate your LEGO S@H purchases from the adds in the right column, if you want to support TBs to some little extent.
For the very unlikely case that any income resulting from this would take some expression (must first, find out how to provide the required tax forms...), it will be converted in prizes for any future contests after expenses and taxes deductions.


Have some nice purchases and happy building!

TBs TechTips 28 - Connecting the PF Receiver to 9V (III)

TBs has already hosted two stories about how to connect an IR-Receiver to a standard 9V LEGO battery box. The trouble with the IR-Receiver is that it doesn't draw its current from the same wires as the motor and so the extension/conversion wire doesn't work in this case.

The first solution involved using a PF battery box (without batteries) [1]:

The second solution consisted of using small strips of aluminium foil to short C1 and the 0V line as well as C2 and the 9V line [2]:

Today I tried my hand at a solution proposed by Rob Hendrix (Brickmodder) in BrickJournal 7.

The solution consists of prying the light grey connector of the conversion cable open (the one that is top PF and bottom 9V) and shorting out 0V with C1 and 9V with C2 from the inside:

Make sure to carefully push the bent black wires between the metal forks that are the bottom part of the connectors. Then place the 9V bottom part on top and press hard to close. Check to see if all the connections are good by using your modified connector to hook an IR Receiver up to a 9V power source. Disconnect and reverse polarity immediately if the IR-Receiver's little green light doesn't go on, as you might damage it if exposed for too long to the wrong polarity.

TBs TechChallenge, 2009 - Reverse 8046 - The submissions

The period to submit an entry for this Challenge has finished last Sunday (15).

Given the difficulty level and some challenging aspects, in my perspective we got a very good adhesion to this Challenge. Either considering the number of submitted entries and discussion generated around the topic, through the comments left and dialogs established into the Challenge original post.

We got a total of 6 participants and 6 submissions. Each one was allowed to submit up to two submissions, but it was not the case for any of the participants.
Five of them were valid submissions and one was more for the fun (you will see below) but which can't be considered as a valid participation in terms of the Challenge's goals and rules (you will also understand why this distinction, below in this post).

In order of submission, we got:

• Eric Albrecht (Blakbird) - US
  
• Scott
  
• Martijn Bosgraaf (Dryw Filtiarn) - NL
  
• Minshik Kong (Sarafiel) - KR
  Sarafiel also provided us with some nice instructions for his submission, which I won't yet disclose, so that we won't get into details about each one's interpretation at this point.
  
• Mike Hatton (Parax) - UK
  
• Nathanaël Kuipers (Industrial Designer) - NL
  

So and before we can proceed to the evaluation phase (pending on instructions delivery by TLG and time availability), I decided to publish here one render provided by the contestants, for each submission.

In order of appearance from top left to bottom right: Eric, Martijn Bosgraaf, Minshik Kong, Mike and Nathanaël.

And also the funny entry from Scott.

You might remember that when I mentioned about the signed box prize for this Challenge winner, I also wrote that might be something additional as a surprise.
In fact I just wanted to avoid that it would have influenced the way, that contestants would send their submissions and so decided to kept it as a little secret, to disclose after the submission period.
This means I'll have also a small symbolic gift to send to the first three contestants, with valid entries (i.e. those entries fulfilling the Challenge goals and rules).
They are three boxes from the 8046 Helicopter itself. This model was made by Markus Kossman, however the boxes to send are not signed, in case you wanted to know.


Let me express here in advance how thankful I am, for the LEGO Technic design team to have accepted to collaborate with TBs , with this Challenge and to have supported us with all the prizes to give away.

8049 B-model, The pneumatic Log Handler

We have here mentioned before, that B-model for the sensation set of the moment (8049, Log Loader) is going to be a Log Handler.

However I guess you have not seen yet any image from this alternative to the 8049 main model!?
So once more at TBs , in exclusive and first hand from TLG to all the Technic fans, here it goes!

Awesome and very good usage from the pneumatic functions!
It may look like quite a large claw for the scale, but somehow imposed by the turntable size. However some real Log Handlers could have such large claws [1, 2, 3] despite slimmer wrists.


Have you liked it?
From December, in a store next to you.

Lego Technic website, got a new face!

From today, LEGO Technic website got a a new face.

Content is basically the same for the moment, but the website look got some renovation, new and more up-to-date software.

Easier maintenance and some new capabilities were also added to the Designers Blog. Soon you should start noticing some of these improvements.

Along with the refreshed website, some new amazing video animations have been added, relative to the 2H2009 sets.

Jump in to see them, at much better quality!