[diamondgeezer]

This thread is best viewed with Kenny Loggins' "Highway To The Danger Zone"

X-Plane owns so much it's untrue:

[Stealth[cro]]

Ooooh... pretty... 's that a Tomcat?

edit: DUH, of course it's a Tomcat... the swept-wings gave it away

[aldo_14]

I remember making a lego tomcat when I was about 11........... the (working - i.e. lockable) swing wings were an utter c*** to do.  Spesh as I didn't have technic or any fancy gubbins.

[CP5670]

I might try building one of these at some point, as I finished my rocket launcher two weeks ago and want to start another project now (although I'm currently leaning towards a more advanced version of the 8485 CC2 helicopter). The F-14's folding wings can be easily done with pneumatic pistons and the tilting aileron geartrains can be kept intact by using u-joints on the wing pivot points. I have now collected some 300-odd lego sets of which 66 are technic, so I should have enough parts.

[mikhael]

CP, you fool. Pnuematic pistons require so much silliness. You can gear up the wings and the like using some basic technic stuff and some creativity. I had mine setup so that if you twisted the cone (standard 2x2->1x1 cylindrical cone) on the nose, the wing swung open and closed. Of course, if you want to make the aelerons work, you're going to have to do some even fancier gearing. Regardless, you can skip the pneumatic silliness.

[CP5670]

If you tell the people on the lugnet.technic newsgroup that pneumatics are "silliness," you'll be flamed to death. You can certainly use standard gears and a motor but they cannot provide the same force that pneumatics can. It depends on how large the model is supposed to be, but anything on the correct scale that is larger than about 18" in length would work better with pneumatics. Seeing as there are only two positions you would really need to have the wings in (extended and folded), the pneumatics would be well suited. It's definitely possible to do this sort of thing with gears and levers alone (I did that for the missile carriage's vertical motion on that rocket launcher) but in this case there isn't much of a point.

[aldo_14]

What's wrong with a hinge?

[mikhael]

We're discussing actuating the hinge, Aldo.

Originally posted by CP5670
If you tell the people on the lugnet.technic newsgroup that pneumatics are "silliness," you'll be flamed to death. You can certainly use standard gears and a motor but they cannot provide the same force that pneumatics can.

People who subscribe to a lugnet newsgroup are deranged to begin with. Its like comic book fans and sports fans and the like. These are not rational people.

If you're worrying about force that much, CP, you're not doing your gearing right. Sure, the Pneumatics would be faster, but they are also damnably ugly, a pain in the ass to work in and require a connection to a pump or tank. I think about the only time I've seen them put to decent use was in a large scale Millenium Falcon model where they were used to actuate the landing gear. That model was big enough to hide the tanks and had a rather clever hideaway pump. For a non-fanatic's model of a Tomcat, I don't think you'd need to go anywhere beyond a very basic gearing.

[aldo_14]

Originally posted by mikhael
We're discussing actuating the hinge, Aldo.

Right..... remeber, the simpler it is, the easier it is to break bits off (whilst making booming noises) when you play with it

 Learnt that ages ago, I did.

[mikhael]

You mean the simpler it is the harder to break, right?

I've found that a solid gear chain, held in place by a good framework of technic girders with cross braces is plenty solid and isn't going to break easily.

Now if you want bits to break off, I can't help you. I design specifically to prevent that.

[CP5670]

People who subscribe to a lugnet newsgroup are deranged to begin with. Its like comic book fans and sports fans and the like. These are not rational people.

They seem to be a friendly bunch to me. I don't read/post stuff there regularly but have been registered for some time now. I have made a few useful trades with people there in the past.

If you're worrying about force that much, CP, you're not doing your gearing right. Sure, the Pneumatics would be faster, but they are also damnably ugly, a pain in the ass to work in and require a connection to a pump or tank. I think about the only time I've seen them put to decent use was in a large scale Millenium Falcon model where they were used to actuate the landing gear. That model was big enough to hide the tanks and had a rather clever hideaway pump. For a non-fanatic's model of a Tomcat, I don't think you'd need to go anywhere beyond a very basic gearing.

The ugly factor depends entirely on how big the model is; if it is sufficiently large, you can easily hide the main piston bodies inside the model. As for being "a pain in the ass," you're just not using them correctly. The only drawback of the pneumatics is the required pump, which takes up some space, but this may or may not be an issue depending on the model's size. As for applications of pneumatics, look at just about any construction vehicle out there. The official 8455 Backhoe Loader and 8868 Airtech Claw Rig sets are very good examples of things done with pneumatics that would be impossible with the current gears.

If you go the purely gear-based route, you would run into the issue of having two independent geartrains on the same pivot point (the other one being the aileron one); this can be dealt with fairly easily but you would get a rather bulkier connection, especially since a worm gear right next to the wing gear would be required to hold the wings in place.

Heck, I'm a master with geartrains and rotational stuff but mediocre with positioning pneumatics and liftarms (you should see my rocket launcher once I get a decent digital camera; I used a messy gear system in one place where almost anyone else would have used pneumatics ), and even I would probably use pneumatics in this case if the model is fairly large.

[mikhael]

I see the utility of pneumatics in places where the real deal would use hydraulics, usually. I just object to the look. I design more for the looks than the mechanics, honestly.

I only used one worm gear to hold my wings in place and it was nowhere near the actual wings. It was buried in the center of the fuselage, where the distribution chain started.

[aldo_14]

Originally posted by mikhael
You mean the simpler it is the harder to break, right?

I've found that a solid gear chain, held in place by a good framework of technic girders with cross braces is plenty solid and isn't going to break easily.

Now if you want bits to break off, I can't help you. I design specifically to prevent that.

But how do you blow it up?

[TrashMan]

Originally posted by aldo_14
I remember making a lego tomcat when I was about 11........... the (working - i.e. lockable) swing wings were an utter c*** to do.  Spesh as I didn't have technic or any fancy gubbins.

Too bad..I was a lego wiz, and I made a great F-14 with working wigns...(made lot's of things...massive spaceships, mecha, robotech Veritechs, castles)...

F-14...the collest, greatest, meanest fighter of them all!
And if anyone sez it aint, I'll break his skull open with a crowbar!

[neo_hermes]

The F-14 is ok
i like the X-15 though

[mikhael]

Originally posted by aldo_14


But how do you blow it up?

I don't.

[aldo_14]

Originally posted by mikhael


I don't.

Ah, well that's where you're missing out.  The primary benefit of lego as a toy is that you can blow stuff up, knock stuff over, etc, and not have to worry about needing to buy it again.

[mikhael]

Nah. THe primary benefit is being able to build things. Blowing it up is for plonkers.

[aldo_14]

Bah.  You must be too old to appreciate it, you mean.

 Er, like I am now.  Bugger.

[mikhael]

Nah. Even as a kid, the point was to build the coolest model and the most functional model. We NEVER blew up the models. We imagined them blowing up. HUGE difference.