Landing light options

My 1976 Cessna 172M uses a PAR 46 size GE4537 lamp for
the landing light (12V, 100W). It is mounted in the lower cowling
under the prop and does not last very long. I suppose the vibration
of the engine kills the life of the bulb. I sure wished Cessna had designed
this landing light installation to allow for replacing the lamp without
having
to remove the cowling. What a pain to replace a light.

I've tried the "rotate it 90 degrees in the holder" trick, but could not
tell that this helped any.

Many people recommend the Quartz Q4509 as a longer life replacement
for the GE 4509 PAR36 size lamp. A best as I can determine, there is no
Quartz version of the 4537. If you have seen these, please let me know
where.

Any other suggestions for a replacement lamp for a GE4537 lamp that
might prove to have a longer life?

Ronnie

If you hold a 4509 light against your ear and hit it with your finger
tip, you can hear the high frequency lightly damped resonance of the
filiament supports. Thinking this resonance was somehow being excited
by the engine vibration and fatiguing the bulb filament, some years ago
I tried two fixes to get around the short life problem of cowl mounted
landing lights. Unfortunately I did both at the same time so I don't
know which one worked.

1) I sprayed silicon on the baffling seals whereever they touch the
cowl to minimize stick-slip engine vibration inputs to the cowl. I
also put some teflon faced tape on the cowl surface whereever the
baffles touched.

2) I removed the 8-32 mounting screws and added some 8-32 male ended
shockmounts and nuts to the landing light frame. This spaced it back
about 1/2 inch from its original position, but it still fit for my
cowling. I found the mounts in a surplus store although they look very
much like the $$ mounts that are used in the gyro instrument panel.
The purpose of the mounts was to add further vibration isolation from
the cowl and engine. Obviously this is not an approved fix, but I
suspect it is more effective than 1) above.

I'm still using the 4509 lites (2), but have not put in a new one for
at least 6 or more years.

Thanks for the input. I think I'll take a look
at the mounting space a little closer and see if
it can accomodate some isolation hardware.

Ronnie

"nrp" wrote in message
oups.com...
If you hold a 4509 light against your ear and hit it with your finger
tip, you can hear the high frequency lightly damped resonance of the
filiament supports. Thinking this resonance was somehow being excited
by the engine vibration and fatiguing the bulb filament, some years ago
I tried two fixes to get around the short life problem of cowl mounted
landing lights. Unfortunately I did both at the same time so I don't
know which one worked.

1) I sprayed silicon on the baffling seals whereever they touch the
cowl to minimize stick-slip engine vibration inputs to the cowl. I
also put some teflon faced tape on the cowl surface whereever the
baffles touched.

2) I removed the 8-32 mounting screws and added some 8-32 male ended
shockmounts and nuts to the landing light frame. This spaced it back
about 1/2 inch from its original position, but it still fit for my
cowling. I found the mounts in a surplus store although they look very
much like the $$ mounts that are used in the gyro instrument panel.
The purpose of the mounts was to add further vibration isolation from
the cowl and engine. Obviously this is not an approved fix, but I
suspect it is more effective than 1) above.

I'm still using the 4509 lites (2), but have not put in a new one for
at least 6 or more years.

Just FYI, found several sources for these type of vibration mounts:

http://www.richco-inc.com/browseframes.asp

http://www.richco-inc.com/browseframes.asp

http://www.smallparts.com/products/descriptions/pm.cfm

http://literature.lord.com/root/other/flexbolt.pdf

http://www.gelmec.co.uk/GelmecElasto...hMountPage.htm


"nrp" wrote in message
oups.com...
If you hold a 4509 light against your ear and hit it with your finger
tip, you can hear the high frequency lightly damped resonance of the
filiament supports. Thinking this resonance was somehow being excited
by the engine vibration and fatiguing the bulb filament, some years ago
I tried two fixes to get around the short life problem of cowl mounted
landing lights. Unfortunately I did both at the same time so I don't
know which one worked.

1) I sprayed silicon on the baffling seals whereever they touch the
cowl to minimize stick-slip engine vibration inputs to the cowl. I
also put some teflon faced tape on the cowl surface whereever the
baffles touched.

2) I removed the 8-32 mounting screws and added some 8-32 male ended
shockmounts and nuts to the landing light frame. This spaced it back
about 1/2 inch from its original position, but it still fit for my
cowling. I found the mounts in a surplus store although they look very
much like the $$ mounts that are used in the gyro instrument panel.
The purpose of the mounts was to add further vibration isolation from
the cowl and engine. Obviously this is not an approved fix, but I
suspect it is more effective than 1) above.

I'm still using the 4509 lites (2), but have not put in a new one for
at least 6 or more years.

It's rated life is 25 hrs (200,000 cp). And it's probably shorter with
more on and off cycles. Plus vibration.

A 4522 at 250w and 290,000 cp would really suck the current, still only
25 hrs.

Have you thought of new wingtips and put in a quartz on on each side?

http://www.rmdaircraft.com/cessna.htm

Great guy to deal with, no connection, just a satisfied customer.

This was discussed before, see my other posts.

John



Ronnie wrote:

My 1976 Cessna 172M uses a PAR 46 size GE4537 lamp for
the landing light (12V, 100W). It is mounted in the lower cowling
under the prop and does not last very long. I suppose the vibration
of the engine kills the life of the bulb. I sure wished Cessna had designed
this landing light installation to allow for replacing the lamp without
having
to remove the cowling. What a pain to replace a light.

I've tried the "rotate it 90 degrees in the holder" trick, but could not
tell that this helped any.

Many people recommend the Quartz Q4509 as a longer life replacement
for the GE 4509 PAR36 size lamp. A best as I can determine, there is no
Quartz version of the 4537. If you have seen these, please let me know
where.

Any other suggestions for a replacement lamp for a GE4537 lamp that
might prove to have a longer life?

Ronnie

FWIW - My a/c is a 172M also (1975).

The condition of your engine mounts are okay, I mean the rubber parts.



Ronnie wrote:

Just FYI, found several sources for these type of vibration mounts:

http://www.richco-inc.com/browseframes.asp

http://www.richco-inc.com/browseframes.asp

http://www.smallparts.com/products/descriptions/pm.cfm

http://literature.lord.com/root/other/flexbolt.pdf

http://www.gelmec.co.uk/GelmecElasto...hMountPage.htm

My 1976 C172M had the same problem. Cessna has or at least had a kit
that stiffened the lower nose bowl and changed the resonant frequency
of the assembly to move it away from the resonance freq of the lamp.
It takes a couple of hours to install the honeycomb and glass cloth
but it has worked for more than 20 years on my plane. Before
installing the kit my landing light would not last more than 3 hours
on or off. Now it lasts for years.
John

On Wed, 01 Mar 2006 19:00:58 GMT, "Ronnie"
wrote:

My 1976 Cessna 172M uses a PAR 46 size GE4537 lamp for
the landing light (12V, 100W). It is mounted in the lower cowling
under the prop and does not last very long. I suppose the vibration
of the engine kills the life of the bulb. I sure wished Cessna had designed
this landing light installation to allow for replacing the lamp without
having
to remove the cowling. What a pain to replace a light.

I've tried the "rotate it 90 degrees in the holder" trick, but could not
tell that this helped any.

Many people recommend the Quartz Q4509 as a longer life replacement
for the GE 4509 PAR36 size lamp. A best as I can determine, there is no
Quartz version of the 4537. If you have seen these, please let me know
where.

Any other suggestions for a replacement lamp for a GE4537 lamp that
might prove to have a longer life?

Ronnie

Hi John,

Well, that certainly is good information. I've never heard
that before. If you have any idea of the kit number or service
bulletin number for this mod, I'd appreciate hearding about it.
So far, searching on Google has not turned up any information on
this.

Ronnie

"John_F" wrote in message
...
My 1976 C172M had the same problem. Cessna has or at least had a kit
that stiffened the lower nose bowl and changed the resonant frequency
of the assembly to move it away from the resonance freq of the lamp.
It takes a couple of hours to install the honeycomb and glass cloth
but it has worked for more than 20 years on my plane. Before
installing the kit my landing light would not last more than 3 hours
on or off. Now it lasts for years.
John

On Wed, 01 Mar 2006 19:00:58 GMT, "Ronnie"
wrote:

My 1976 Cessna 172M uses a PAR 46 size GE4537 lamp for
the landing light (12V, 100W). It is mounted in the lower cowling
under the prop and does not last very long. I suppose the vibration
of the engine kills the life of the bulb. I sure wished Cessna had
designed
this landing light installation to allow for replacing the lamp without
having
to remove the cowling. What a pain to replace a light.

I've tried the "rotate it 90 degrees in the holder" trick, but could not
tell that this helped any.

Many people recommend the Quartz Q4509 as a longer life replacement
for the GE 4509 PAR36 size lamp. A best as I can determine, there is no
Quartz version of the 4537. If you have seen these, please let me know
where.

Any other suggestions for a replacement lamp for a GE4537 lamp that
might prove to have a longer life?

Ronnie

The rmd wingtip lights look nice. I didn't see any pricing
info on their web site. I wonder how expensive these are.

In searching and reading you prior posts, I see that the
GE H7635 is a halogen 12V, 50W PAR 46 lamp that should
fits into the GE 4537 mount. Looks like bulbs.com has them
for $14.95. I think I'll try one of these.



"The Visitor" wrote in message
...
It's rated life is 25 hrs (200,000 cp). And it's probably shorter with
more on and off cycles. Plus vibration.

A 4522 at 250w and 290,000 cp would really suck the current, still only 25
hrs.

Have you thought of new wingtips and put in a quartz on on each side?

http://www.rmdaircraft.com/cessna.htm

Great guy to deal with, no connection, just a satisfied customer.

This was discussed before, see my other posts.

John



Ronnie wrote:

My 1976 Cessna 172M uses a PAR 46 size GE4537 lamp for
the landing light (12V, 100W). It is mounted in the lower cowling
under the prop and does not last very long. I suppose the vibration
of the engine kills the life of the bulb. I sure wished Cessna had
designed
this landing light installation to allow for replacing the lamp without
having
to remove the cowling. What a pain to replace a light.

I've tried the "rotate it 90 degrees in the holder" trick, but could not
tell that this helped any.

Many people recommend the Quartz Q4509 as a longer life replacement
for the GE 4509 PAR36 size lamp. A best as I can determine, there is no
Quartz version of the 4537. If you have seen these, please let me know
where.

Any other suggestions for a replacement lamp for a GE4537 lamp that
might prove to have a longer life?

Ronnie