A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Home Built
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Hinges under stress - mechanical engineering type question



 
 
Thread Tools Display Modes
  #1  
Old August 1st 03, 02:21 AM
Peter Dohm
external usenet poster
 
Posts: n/a
Default

Corrie wrote:

john wrote in message . ..
On 30 Jul 2003 16:56:37 -0700, (Corrie) wrote:


"MS20001P aluminum hinge is extruded. The closed hinge loops cannot be
pulled apart. Furnished with hinge pin. Anodized finish."


Thanks. How much stress can it take, though? That's the question.
Probably the hinge pin or the rivets holding the plates would be the
first to fail at a few hundred pounds, but still... musing I
suppose one could order some and find out.... If the specific alloy
were known, it could be looked up.
http://ourworld.compuserve.com/homep...orhis/T003.htm shows
yield and tensile strengths for a number of allows. They tend to be
around 30kpsi. The catalog doesn't give the thickness of the flange.
Assume it's .1", and the hinge is 6" long, that's .6 sq. in, at
30kpsi.. 18,000 lbs? But some alloys are as low as 5kpsi - that's
3,000 lbs. Impressive for a small hinge, but would it suffice for the
application? Marginal at best, I think.

The largest hinge at AS&S is just 2" wide, and they all seem to have
the same size pin - .089 stainless. That's .006 sq. in. area. I
can't find a reference for shear strength for stainless, but taking an
optimistic SWAG at 200kpsi (the highest yield strength for drawn ss
referenced at http://ourworld.compuserve.com/homep...orhis/T006.htm),
that's 200,000 x .006 = 1200 lbs. Not nearly good enough. /musing

My guess is that if it's not specifically rated and labeled, it's
unknown. Not something to put in a critical area. So, then, back to
the original question. Assuming you don't have the ability to extrude
a larger piece of aluminum (in order to use a larger pin), how *do*
you solve the problem?



I really feel like a big dummy, because I may have missed the obvious,
and I know that I may have nothing usefull to add after all ... but ...

What are these hinges supposed to hold???
pressurized canopy?
undercarriage trunion?
control surface?
some kind of single hinge application?

Peter
  #2  
Old August 1st 03, 03:11 AM
Bill Daniels
external usenet poster
 
Posts: n/a
Default


"Peter Dohm" wrote in message
...
Corrie wrote:


I really feel like a big dummy, because I may have missed the obvious,
and I know that I may have nothing usefull to add after all ... but ...

What are these hinges supposed to hold???
pressurized canopy?
undercarriage trunion?
control surface?
some kind of single hinge application?

Peter


Well, the Sisu 1A sailplane used aircraft grade piano hinges in instead of
spar root fittings. The right and left wings were joined to each other with
1/16" piano wire inserted through hinges riveted to the upper and lower wing
skins. The fuselage was hung from the joined wings.

See: http://www.nasm.si.edu/nasm/aero/aircraft/arlington.htm

Bill Daniels

  #3  
Old August 1st 03, 10:13 PM
Corrie
external usenet poster
 
Posts: n/a
Default

Peter Dohm asked, quite reasonably
What are these hinges supposed to hold???


The spar. I'm thinking about the possibility of considering the
feasibility of investigating a folding wing. The spar would have a
hinge installed top and bottom. To fold the wing you remove the
bottom pin. GW of the aircraft in mind is ~1500lb. It would need to
be able to take 6 g's, hence my concern about strength.

The sailplane may have used standard piano hinges, but it was about
500 lbs, and probably not stressed for more than 3 g's.
  #4  
Old August 1st 03, 10:36 PM
Ernest Christley
external usenet poster
 
Posts: n/a
Default

Corrie wrote:
Peter Dohm asked, quite reasonably

What are these hinges supposed to hold???



The spar. I'm thinking about the possibility of considering the
feasibility of investigating a folding wing. The spar would have a
hinge installed top and bottom. To fold the wing you remove the
bottom pin. GW of the aircraft in mind is ~1500lb. It would need to
be able to take 6 g's, hence my concern about strength.

The sailplane may have used standard piano hinges, but it was about
500 lbs, and probably not stressed for more than 3 g's.


The Dyke Delta does this with a 1/2" pin that passes through fittings in
the top and bottom spar. Max gross is 1950lbs.

--
----Because I can----
http://www.ernest.isa-geek.org/
------------------------

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 06:38 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 AviationBanter.
The comments are property of their posters.