Can anybody point to a source for small, flimsy, aluminum hinges
suitable for replacing those on the gear doors of a glider with
retractable gear? The idea is to attach the hinges to the doors and
fuselage with aluminum rivets, and hope that only the aluminum parts
break the next time a door gets broken off, and not any fiberglass.

Specifically looking for hinges for an LS4 right now, and the broken
hinges were only about an inch long.

Piano hinge at your local hardware store. Cut to fit. Worked on the LS-4 I landed out. I recall using bolts and concur it's better the hinge fail than the fiberglass.

The trick is making sure the doors close completely.

On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
> Can anybody point to a source for small, flimsy, aluminum hinges
> suitable for replacing those on the gear doors of a glider with
> retractable gear? The idea is to attach the hinges to the doors and
> fuselage with aluminum rivets, and hope that only the aluminum parts
> break the next time a door gets broken off, and not any fiberglass.
>
> Specifically looking for hinges for an LS4 right now, and the broken
> hinges were only about an inch long.
I did a search for "aluminum piano hinge" and had a bunch of hits. Here is a link to a selection on Amazon....... https://www.amazon.com/s?k=aluminum+piano+hinge&gclid=CjwKCAiA5sieBhBnEiwAR9oh2vlqsPk4eOjnbfy8htyzF34bHS4PHDo9htZmqUBvYgZJRh4LSc91_RoCLWsQAvD_BwE&hvadid=616990817498&hvdev=t&hvlocphy=9003603&hvnetw=g&hvqmt=e&hvrand=4071482660401343263&hvtargid=kwd-1070675891&hydadcr=24634_13611738&tag=googhydr-20&ref=pd_sl_8jyvz0795l_e

Perhaps e-mail Bob at HP Aircraft LLC?

On Wednesday, January 25, 2023 at 3:16:02 PM UTC-8, Moshe Braner wrote:
> Can anybody point to a source for small, flimsy, aluminum hinges
> suitable for replacing those on the gear doors of a glider with
> retractable gear? The idea is to attach the hinges to the doors and
> fuselage with aluminum rivets, and hope that only the aluminum parts
> break the next time a door gets broken off, and not any fiberglass.
>
> Specifically looking for hinges for an LS4 right now, and the broken
> hinges were only about an inch long.

Perhaps using steel hinges with an aluminum, copper, or plastic pin that can easily shear would be better than flimsy hinges.

On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
> Can anybody point to a source for small, flimsy, aluminum hinges
> suitable for replacing those on the gear doors of a glider with
> retractable gear? The idea is to attach the hinges to the doors and
> fuselage with aluminum rivets, and hope that only the aluminum parts
> break the next time a door gets broken off, and not any fiberglass.
>
> Specifically looking for hinges for an LS4 right now, and the broken
> hinges were only about an inch long.
Aircraft Spruce stocks aluminum piano hinge that makes a good material for gear door hinges. If you want to provide easier break away use 1/8 inch aluminum pop rivets.
UH

On 1/26/2023 8:40 AM, Hank Nixon wrote:
> On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
>> Can anybody point to a source for small, flimsy, aluminum hinges
>> suitable for replacing those on the gear doors of a glider with
>> retractable gear? The idea is to attach the hinges to the doors and
>> fuselage with aluminum rivets, and hope that only the aluminum parts
>> break the next time a door gets broken off, and not any fiberglass.
>>
>> Specifically looking for hinges for an LS4 right now, and the broken
>> hinges were only about an inch long.
> Aircraft Spruce stocks aluminum piano hinge that makes a good material for gear door hinges. If you want to provide easier break away use 1/8 inch aluminum pop rivets.
> UH
>

In this case, a spring detached, so the door hung down while pushing the
fuselage into the trailer. The now-broken hinges were thin aluminum and
attached with aluminum rivets. Both the rivets and the hinges
themselves broke. And the fiberglass was left intact, yay! Regarding
the suggestion (from somebody else) to use steel hinges with a weak pin,
I think with the impact likely to be along the direction of the pin,
there would be a lot more impact force hitting the "wings" of the hinge.
I see that we can get plastic (acrylic) hinges of just the right size
- both the body and the pin are plastic - would that be a good idea?

On Wednesday, January 25, 2023 at 4:16:02 PM UTC-7, Moshe Braner wrote:
> Can anybody point to a source for small, flimsy, aluminum hinges
> suitable for replacing those on the gear doors of a glider with
> retractable gear? The idea is to attach the hinges to the doors and
> fuselage with aluminum rivets, and hope that only the aluminum parts
> break the next time a door gets broken off, and not any fiberglass.
>
> Specifically looking for hinges for an LS4 right now, and the broken
> hinges were only about an inch long.

I can barely spell "fix a glider," but would nylon hinges work, backed up by cloth tape inside the fuselage?

Raul Boerner

The longitudinal force may still damage fiberglass or carbon parts. I
vote for the flimsy rivets holding the doors on.

Dan
5J

On 1/26/23 07:21, Moshe Braner wrote:
> On 1/26/2023 8:40 AM, Hank Nixon wrote:
>> On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
>>> Can anybody point to a source for small, flimsy, aluminum hinges
>>> suitable for replacing those on the gear doors of a glider with
>>> retractable gear? The idea is to attach the hinges to the doors and
>>> fuselage with aluminum rivets, and hope that only the aluminum parts
>>> break the next time a door gets broken off, and not any fiberglass.
>>>
>>> Specifically looking for hinges for an LS4 right now, and the broken
>>> hinges were only about an inch long.
>> Aircraft Spruce stocks aluminum piano hinge that makes a good material
>> for gear door hinges. If you want to provide easier break away use 1/8
>> inch aluminum pop rivets.
>> UH
>>
>
> In this case, a spring detached, so the door hung down while pushing the
> fuselage into the trailer.  The now-broken hinges were thin aluminum and
> attached with aluminum rivets.  Both the rivets and the hinges
> themselves broke.  And the fiberglass was left intact, yay!  Regarding
> the suggestion (from somebody else) to use steel hinges with a weak pin,
> I think with the impact likely to be along the direction of the pin,
> there would be a lot more impact force hitting the "wings" of the hinge.
>  I see that we can get plastic (acrylic) hinges of just the right size
> - both the body and the pin are plastic - would that be a good idea?
>

On Thursday, January 26, 2023 at 11:16:08 AM UTC-5, Moshe Braner wrote:
> On 1/26/2023 8:40 AM, Hank Nixon wrote:
> > On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
> >> Can anybody point to a source for small, flimsy, aluminum hinges
> >> suitable for replacing those on the gear doors of a glider with
> >> retractable gear? The idea is to attach the hinges to the doors and
> >> fuselage with aluminum rivets, and hope that only the aluminum parts
> >> break the next time a door gets broken off, and not any fiberglass.
> >>
> >> Specifically looking for hinges for an LS4 right now, and the broken
> >> hinges were only about an inch long.
> > Aircraft Spruce stocks aluminum piano hinge that makes a good material for gear door hinges. If you want to provide easier break away use 1/8 inch aluminum pop rivets.
> > UH
> >
> In this case, a spring detached, so the door hung down while pushing the
> fuselage into the trailer. The now-broken hinges were thin aluminum and
> attached with aluminum rivets. Both the rivets and the hinges
> themselves broke. And the fiberglass was left intact, yay! Regarding
> the suggestion (from somebody else) to use steel hinges with a weak pin,
> I think with the impact likely to be along the direction of the pin,
> there would be a lot more impact force hitting the "wings" of the hinge.
> I see that we can get plastic (acrylic) hinges of just the right size
> - both the body and the pin are plastic - would that be a good idea?

Seems like the seeking of an engineering solution to a procedural problem. I'd put it back as constructed and make sure the springs work and the gear is up.
UH

On Thursday, January 26, 2023 at 1:23:52 PM UTC-5, Dan Marotta wrote:
> The longitudinal force may still damage fiberglass or carbon parts. I
> vote for the flimsy rivets holding the doors on.
>
> Dan
> 5J
> On 1/26/23 07:21, Moshe Braner wrote:
> > On 1/26/2023 8:40 AM, Hank Nixon wrote:
> >> On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
> >>> Can anybody point to a source for small, flimsy, aluminum hinges
> >>> suitable for replacing those on the gear doors of a glider with
> >>> retractable gear? The idea is to attach the hinges to the doors and
> >>> fuselage with aluminum rivets, and hope that only the aluminum parts
> >>> break the next time a door gets broken off, and not any fiberglass.
> >>>
> >>> Specifically looking for hinges for an LS4 right now, and the broken
> >>> hinges were only about an inch long.
> >> Aircraft Spruce stocks aluminum piano hinge that makes a good material
> >> for gear door hinges. If you want to provide easier break away use 1/8
> >> inch aluminum pop rivets.
> >> UH
> >>
> >
> > In this case, a spring detached, so the door hung down while pushing the
> > fuselage into the trailer. The now-broken hinges were thin aluminum and
> > attached with aluminum rivets. Both the rivets and the hinges
> > themselves broke. And the fiberglass was left intact, yay! Regarding
> > the suggestion (from somebody else) to use steel hinges with a weak pin,
> > I think with the impact likely to be along the direction of the pin,
> > there would be a lot more impact force hitting the "wings" of the hinge.
> > I see that we can get plastic (acrylic) hinges of just the right size
> > - both the body and the pin are plastic - would that be a good idea?
> >
When doing the poprivets, you could also drive the mandrel out so less cross section to shear if it makes you feel better.

True what you say, but my LS-6 partner broke the front of a gear door
during land out. I had to repair the door rather than simply reattach
it with aluminum rivets.

Dan
5J

On 1/26/23 11:49, Hank Nixon wrote:
> On Thursday, January 26, 2023 at 11:16:08 AM UTC-5, Moshe Braner wrote:
>> On 1/26/2023 8:40 AM, Hank Nixon wrote:
>>> On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
>>>> Can anybody point to a source for small, flimsy, aluminum hinges
>>>> suitable for replacing those on the gear doors of a glider with
>>>> retractable gear? The idea is to attach the hinges to the doors and
>>>> fuselage with aluminum rivets, and hope that only the aluminum parts
>>>> break the next time a door gets broken off, and not any fiberglass.
>>>>
>>>> Specifically looking for hinges for an LS4 right now, and the broken
>>>> hinges were only about an inch long.
>>> Aircraft Spruce stocks aluminum piano hinge that makes a good material for gear door hinges. If you want to provide easier break away use 1/8 inch aluminum pop rivets.
>>> UH
>>>
>> In this case, a spring detached, so the door hung down while pushing the
>> fuselage into the trailer. The now-broken hinges were thin aluminum and
>> attached with aluminum rivets. Both the rivets and the hinges
>> themselves broke. And the fiberglass was left intact, yay! Regarding
>> the suggestion (from somebody else) to use steel hinges with a weak pin,
>> I think with the impact likely to be along the direction of the pin,
>> there would be a lot more impact force hitting the "wings" of the hinge.
>> I see that we can get plastic (acrylic) hinges of just the right size
>> - both the body and the pin are plastic - would that be a good idea?
>
> Seems like the seeking of an engineering solution to a procedural problem. I'd put it back as constructed and make sure the springs work and the gear is up.
> UH

When I first got my Pik 20 was shocked at the truly ugly flimsy hardware store hinges on the gear doors. It was in explicit language explained to me that their selection was deliberate. Pik gear doors will sometimes at least semi-detach when landing in grass that needs a serious mow on the airfield was the message and a landout without knocking one or both off at least a bit was a special day. So I acquired a clutch of cheap and ugly hinges from one of the big hardware stores and was a happy fixer. Oh and use small screws too. It is easy to refill the holes when they get stretched.

n Thursday, January 26, 2023 at 2:02:14 PM UTC-5, Dan Marotta wrote:
> True what you say, but my LS-6 partner broke the front of a gear door
> during land out. I had to repair the door rather than simply reattach
> it with aluminum rivets.
>
> Dan
> 5J
> On 1/26/23 11:49, Hank Nixon wrote:
> > On Thursday, January 26, 2023 at 11:16:08 AM UTC-5, Moshe Braner wrote:
> >> On 1/26/2023 8:40 AM, Hank Nixon wrote:
> >>> On Wednesday, January 25, 2023 at 6:16:02 PM UTC-5, Moshe Braner wrote:
> >>>> Can anybody point to a source for small, flimsy, aluminum hinges
> >>>> suitable for replacing those on the gear doors of a glider with
> >>>> retractable gear? The idea is to attach the hinges to the doors and
> >>>> fuselage with aluminum rivets, and hope that only the aluminum parts
> >>>> break the next time a door gets broken off, and not any fiberglass.
> >>>>
> >>>> Specifically looking for hinges for an LS4 right now, and the broken
> >>>> hinges were only about an inch long.
> >>> Aircraft Spruce stocks aluminum piano hinge that makes a good material for gear door hinges. If you want to provide easier break away use 1/8 inch aluminum pop rivets.
> >>> UH
> >>>
> >> In this case, a spring detached, so the door hung down while pushing the
> >> fuselage into the trailer. The now-broken hinges were thin aluminum and
> >> attached with aluminum rivets. Both the rivets and the hinges
> >> themselves broke. And the fiberglass was left intact, yay! Regarding
> >> the suggestion (from somebody else) to use steel hinges with a weak pin,
> >> I think with the impact likely to be along the direction of the pin,
> >> there would be a lot more impact force hitting the "wings" of the hinge.
> >> I see that we can get plastic (acrylic) hinges of just the right size
> >> - both the body and the pin are plastic - would that be a good idea?
> >
> > Seems like the seeking of an engineering solution to a procedural problem. I'd put it back as constructed and make sure the springs work and the gear is up.
> > UH