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  • 3 weeks later...
On 4/28/2018 at 8:08 PM, The Rat said:

Looking at 104s in natural metal finish, and rarely are the wings left bare, they're usually painted, and often white. Any particular reason for that? TIA
 

This has  been discussed recently on other forums, which might be why no one has responded before now.

 

The wings were painted White on top and ADC Gray on the bottom.  A couple of reasons were given; one was to improve the laminar flow of the wing by applying a smooth coating of paint.  The reason for the white top coat was supposedly to dissipate heat on the top surface which could interfere with the operation of flaps or other moving parts.  I can't personally vouch for either, but this seems to be the consensus among those who claim to know.

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On 5/14/2018 at 10:54 PM, Neptune48 said:

This has  been discussed recently on other forums, which might be why no one has responded before now.

 

The wings were painted White on top and ADC Gray on the bottom.  A couple of reasons were given; one was to improve the laminar flow of the wing by applying a smooth coating of paint.  The reason for the white top coat was supposedly to dissipate heat on the top surface which could interfere with the operation of flaps or other moving parts.  I can't personally vouch for either, but this seems to be the consensus among those who claim to know.

 

👍 Thanks!

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  • 2 weeks later...
  • 3 weeks later...
On 5/15/2018 at 4:54 AM, Neptune48 said:

This has  been discussed recently on other forums, which might be why no one has responded before now.

 

The wings were painted White on top and ADC Gray on the bottom.  A couple of reasons were given; one was to improve the laminar flow of the wing by applying a smooth coating of paint.  The reason for the white top coat was supposedly to dissipate heat on the top surface which could interfere with the operation of flaps or other moving parts.  I can't personally vouch for either, but this seems to be the consensus among those who claim to know.

 

IIRC, there were some early crashes attributed to hot bare metal wings cooling down very rapidly during take-off, leading to flap problems (hope I remembered that part correctly). Coupled with early downward ejection seats, that cost a few pilot lives.The white paint kept the wing temperature down.


Rob

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Never heard of the heat expansion/cooling issue with the wings before. The Thermal Expansion Coefficient of the materials used in the wing construction is pretty low. The wing skins themselves are made from 7075-T6 aluminum which has a thermal expansion of about 23 microns per meter from 20 - 200 degrees Celsius. That's smaller than the diameter of a white blood cell. 

 

There are several examples of darker paint schemes and special schemes with black wings so the heat was not an issue.

 

The main reason for painted wings in the first place is due to aerodynamics and corrosion control. All of the fasteners and screws on the wing skins were filled with aluminized putty which required a top coat of paint. The paint also protected the machined wing skins which were prone to corrosion. The Early YF/F-104A's didn't have this putty initially so the wings were left bare metal. Now the reason for the white paint was more likely to keep the surface cooler for maintainers. Nothing quite like trying to work on top of a hot frying pan in the sun.

 

Cheers,

 

John

 

 

 

 

 

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  • 2 months later...

I always heard the Corrosion story as well.

as far as helping out maintainers, well I don't remember them ever doing anything to make our lives easier. 🙂

However, they did issue us gloves at Nellis to handle hot tools.

Ever grab a pair of cannon plug pliers after they have been sitting in an open toolbox on the flightline for about an hour?

yeah. 

 

Jester

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  • 1 month later...

I wanted how the nose cone of F-104 was stored when removed from aircraft? Was there a support base for it? Or was it a hinging mechanism that let the technicians open the cone for access to radar. 

 

Any picture will greatly help. 

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45 minutes ago, stalal said:

I wanted how the nose cone of F-104 was stored when removed from aircraft? Was there a support base for it? Or was it a hinging mechanism that let the technicians open the cone for access to radar. 

 

Any picture will greatly help. 

 

The fiberglass radome plus the first metal section can be pulled forward for access to the radar black boxes (not the antenna). Here's one picture where you can see that somewhat.

 

f104d-08.jpg

 

Rob

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  • 1 month later...
On 6/13/2018 at 7:48 PM, Rob de Bie said:

 

IIRC, there were some early crashes attributed to hot bare metal wings cooling down very rapidly during take-off, leading to flap problems (hope I remembered that part correctly). Coupled with early downward ejection seats, that cost a few pilot lives.The white paint kept the wing temperature down.


Rob

 

It took me a couple of months to find my source again, but here it is, from rec.models.scale in 2002:

 

https://groups.google.com/forum/#!searchin/rec.models.scale/variable$20stator$20system|sort:date/rec.models.scale/htfUxmCm7sw/6xClpm_ypA8J

 

It seems my first explanation was partly right, partly wrong.

 

Maybe some crash reports can be consulted to check whether these accidents really happened, and were caused by the problem described? Then we can put this question to bed forever 🙂

 

Rob

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I would say that's a very 'alternative reason' but totally incorrect. The source has no idea what they are talking about and has no factual content or references.

 

There is a lot of misinformation in that post regarding the design and implementation of the J79 into the F-104 airframe. At no point were thermocouples installed in the wings in an effort to control the VSV system on the J79 due to airframe heating. The actual limiting factor for the airframe heating is the J79 engine front frame and generator cooling air temperature and not the aluminum structure. The effects of high speed heating on the F-104 were well understood by Lockheed engineers and the Aluminum used in the structure was more than sufficient to cope with this heating.

 

As for Eglin AFB accidents, there were only 4 F-104's lost at Eglin over the years and only one was a takeoff accident when the engine failed. 

 

Interesting F-104 accident list.

 

http://www.i-f-s.nl/F-104 Accidents/

 

Eglin AFB accident list.

 

https://en.wikipedia.org/wiki/List_of_aircraft_accidents_at_Eglin_Air_Force_Base

 

The majority of early F-104 accidents were due to engine failure/fire, hydraulic failure or electrical failure.

 

Cheers,

 

John

 

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Also to dispell any myths about thermal issues with the wings, there is ducting in the wings  for BLC, our Boundary Layer Control, so when the flap is lowered to "Land" it opens nozzles that allow bleed air from the compressor (Very freaking hot air) to flow over the ings. this is also a reason why the throttle have to be up quite high on approach, to supply air.

 

The radome can be taken off all the way, and just placed on the ground next to the aircraft, no issues. No specialty cart or tool needed to hang it or store it. It is also light enough that you can man handle it alone.

 

Cheers

Harald

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42 minutes ago, Winnie said:

Also to dispell any myths about thermal issues with the wings, there is ducting in the wings  for BLC, our Boundary Layer Control, so when the flap is lowered to "Land" it opens nozzles that allow bleed air from the compressor (Very freaking hot air) to flow over the ings. this is also a reason why the throttle have to be up quite high on approach, to supply air.

 

The radome can be taken off all the way, and just placed on the ground next to the aircraft, no issues. No specialty cart or tool needed to hang it or store it. It is also light enough that you can man handle it alone.

 

Cheers

Harald

 

Good point about the BLC temperature. The bleed air is taken from the last compressor stage, so it must be very hot indeed. On the G-model, both wing and flap skins are made of 7075-T6. Maybe there's no aging problem with 7075 when subjected to temperatures above 130 degr C ?

 

Regarding the radome, I'm not so sure. The radome is fitted with a ton of screws, so it's a lot of work to remove it. When we had a 104 in our lab, the radome was off, and I once tried to lift it. I found it very heavy, and extremely difficult to handle, due to the awkward shape, the length and the smooth / slippery surface.

 

I just checked the Daco 104 book, and on page 4 it shows the radome plus first sheet metal section moved forward for access to the radar systems (not antenna). Furthermore, it shows that the radome plus first sheet metal section can be taken off together easily, without undoing all the radome screws. A special stand is shown to store the nose section.

 

Rob

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17 hours ago, Rob de Bie said:

Regarding the radome, I'm not so sure. The radome is fitted with a ton of screws, so it's a lot of work to remove it. When we had a 104 in our lab, the radome was off, and I once tried to lift it. I found it very heavy, and extremely difficult to handle, due to the awkward shape, the length and the smooth / slippery surface.

 

I just checked the Daco 104 book, and on page 4 it shows the radome plus first sheet metal section moved forward for access to the radar systems (not antenna). Furthermore, it shows that the radome plus first sheet metal section can be taken off together easily, without undoing all the radome screws. A special stand is shown to store the nose section.

 

Found the weight by accident in the SRM:

 

radome alone: 88 lbs / 40 kg

radome plus aluminum section: 116 lbs / 53 kg

 

Rob

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  • 2 weeks later...

The radome was held on with 4 latches secured with 1 screw each. Not too bad at all.

 

It would slide forward maybe 18 inches, and then could be lifted off easily enough. I did this with 1 other guy several times. Line maintenance would just leave the radome with the flat section on the ground. I'm sure there were special maintenance stands for them but I doubt they were much in use other than in special cases. 

 

The radome also had connectors for static discharge and Pitot tube air line. And on the CF-104 I played with, connector to the RWR receiver.

 

 

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48 minutes ago, Winnie said:

The radome was held on with 4 latches secured with 1 screw each. Not too bad at all.

 

It would slide forward maybe 18 inches, and then could be lifted off easily enough. I did this with 1 other guy several times. Line maintenance would just leave the radome with the flat section on the ground. I'm sure there were special maintenance stands for them but I doubt they were much in use other than in special cases. 

 

The radome also had connectors for static discharge and Pitot tube air line. And on the CF-104 I played with, connector to the RWR receiver.

 

Here are two drawings from the Structural Repair Manual. The glass fiber radome (part 1) is attached with a lot of screws to the first aluminum section (2). After releasing four latches, together (4) they slide forward for radar access, or can be taken off for full access. The weights that I reported earlier are in the table. The screws and latches can be seen in the photo.


Rob

 

 

f104-01.jpg

f-104g_fx-47_03_of_39.jpg

Edited by Rob de Bie
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17 hours ago, Rob de Bie said:

 

Here are two drawings from the Structural Repair Manual. The glass fiber radome (part 1) is attached with a lot of screws to the first aluminum section (2). After releasing four latches, together (4) they slide forward for radar access, or can be taken off for full access. The weights that I reported earlier are in the table. The screws and latches can be seen in the photo.


Rob

 

 

f104-01.jpg

f-104g_fx-47_03_of_39.jpg

 

Yeah I understand, however, the fibreglass nose piece would only ever be taken off, if broken. The Nose Cone from the firewall, could be opened daily if so inclined.

 

It even explains on the stencil how to insure the nose is latched properly.


Best Regards

Harald

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