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Subject: 
Re: Props for Hovercraft
Newsgroups: 
lugnet.technic
Date: 
Sat, 8 Feb 2003 18:28:29 GMT
Viewed: 
2479 times
  
You guys are bound and determined to spend my whole weekend tinkering on
this,
aren't you?  ;-)

I reproduced Ross's setup using a gray peg, a black friction peg, and an old
black friction peg.  I still get what I consider pretty poor performance
(with fresh
batteries).  It seems to me that the lineup just isn't straight enough to
run smoothly.
Maybe my propellor part is a little funky.

I have not tried lubricating, as Stephane suggests.

I tried Kevin's suggestion briefly.  The "legs" of the Technic turntable hit
the prop
blades, and would have to be removed.  Also, I think the friction of the
turntable
itself would be pretty high.

I also experimented a little with David's crown gear suggestion.  I once cut
a big
hole in the middle of a z24 gear and used that to test the grip of an
unmodified z24
crown gear.  I think the grip is respectable, but I'm not convinced it's
good enough.
Also "the annoying bump" on the crown gear is the very thing that grips the
axle, so
cutting it down seems like it would increase the lineup error.

I think I shall leave this problem to the more fertile minds.  Good luck
fellas ...

Mark Haye

"David Arnon" <arnon@NOSPAMsilicon-value.com> wrote in message
news:H9zz9H.KuG@lugnet.com...
In lugnet.technic, Ross Crawford writes:
In lugnet.technic, Mark Haye writes:
Yes, I had tried that.  I was unable to prevent all the rotation at the • friction pin,
and even a small amount of movement there caused significant • wobble/binding.

Well I did a little test, heres the pics:

http://www.brickshelf.com/gallery/RoscoHead/etc/prop/dcp_1409.jpg
http://www.brickshelf.com/gallery/RoscoHead/etc/prop/dcp_1410.jpg
http://www.brickshelf.com/gallery/RoscoHead/etc/prop/dcp_1411.jpg

Note that the propeller shaft is cylindrical, not "x" axle-shape, so
friction is much greater than standard axle.

It worked reasonably well, even with no lubrication and old batteries. I
reckon with some lube, and maybe even a more powerful motor, it would • work
really well.

Oh, and running the axle vertically runs better than horizontally, so • even
better for hovercraft 8?)

ROSCO

Nice design.
Oh man, the design of the 24t gear at the back of this propeler is realy
lame.  That whole part is very un-legoish.

1) Perhaps you could use the old friction connector instead of the new • one:
i.e. part 4459 instead of part 2780.
(see: http://w3.one.net/~hughesj/technica/registry/connect/conn_2.php)
It should grip the two gears together better.

2) If you're willing to cut (*gasp*) the annoying "bump" on one of your
Technic Crown Gear 24t I think it should "grip" the 24t gear • on
all sides pretty well. I don't have the propeller piece, so let me know if
that works (that is, if you're willing to cut Lego, of course)

- David



Message has 1 Reply:
  Re: Props for Hovercraft
 
"Mark Haye" <markhaye@netzero.net> wrote in message news:HA05tr.EJx@lugnet.com... (...) Offcourse, we dont give up before we have succeeded :) I'm just been bitten of this LEGO-flying machine virus .... (...) old (...) hit (...) Whatever speed you (...) (21 years ago, 8-Feb-03, to lugnet.technic)

Message is in Reply To:
  Re: Props for Hovercraft
 
(...) Nice design. Oh man, the design of the 24t gear at the back of this propeler is realy lame. That whole part is very un-legoish. 1) Perhaps you could use the old friction connector instead of the new one: i.e. part 4459 instead of part 2780. (...) (21 years ago, 8-Feb-03, to lugnet.technic)

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