Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-20-2012, 07:17 AM   #46
Veteran Member




Join Date: Feb 2011
Posts: 4,893
QuoteOriginally posted by Docrwm Quote
Exhaust gases are diverted in most airliners to warm the cargo holds so that things don't freeze to the point that plastics would become brittle (like those used in suitcases, etc.).
There's no exhaust gas in the cargo hold. It could be energy from the exhaust gas via a heat exchanger, etc. I was under the impression that there is no 'seal' between the passenger cabin and the cargo hold (and such a seal would in fact be difficult to implement).

07-20-2012, 07:18 AM   #47
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
Original Poster
QuoteOriginally posted by ElJamoquio Quote
There's no exhaust gas in the cargo hold. It could be energy from the exhaust gas via a heat exchanger, etc. I was under the impression that there is no 'seal' between the passenger cabin and the cargo hold (and such a seal would in fact be difficult to implement).
I never said it was pumped in, merely diverted - which it is - they use the thermal energy from the engine exhaust to heat the cargo hold. Geesch.
07-20-2012, 08:28 AM   #48
Loyal Site Supporter
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,910
QuoteOriginally posted by lytrytyr Quote
Do you know how the temperature is regulated in the shipping companies' cargo planes?
As a matter of fact I do. I taught those systems for many years. NO TURBINE EXHAUST GASES ARE INVOLVED IN THE CABIN ENVIRONMENTAL AIR SOURCES!

In simple terms, a small jet turbine drives a separate compressor stage turbine that compresses and heats outside ambient air to 200-300 deg F. It's then passed through a de-compression stage to cool it to just above freezing. The two air sources are then mixed to produce thermostatically controlled, cabin and cargo compartment zone temperatures between about 40-80 deg F.

There's no reason not to regulate temperature to a healthy, comfortable level since the same environment is shared by the flight crew -- cargo or otherwise.

Note that the process lowers humidity to an unhealthy level. If there's not a load of sweaty, exhaling humans to re-humidify the air in passenger service (HEPA-class filtration is used), humidifiers are employed to satisfy crew health needs. Environmental systems are essentially identical in both passenger and cargo aircraft - one design suits all purposes.

The temperature issues are not with a normal aircraft in flight, but with unregulated cargo bay conditions on the ground in hot or freezing weather. Any environmental system failure in flight will soon have the aircraft on the ground.

If temperature and humidity aren't very well controlled in any aircraft, excessive condensation forms on the INSIDE of the aluminum hull. Over time that soaks the insulation, adds tons of weight, freezes/thaws, grows nasty fungus and causes really bad corrosion problems.

Myths and BS aside, if something happens to you or your belongings in flight it will be because of human failure or unanticipated mechanical failure, sort'a like havin' the UPS truck T-boned by a train; not an intentional design decision. The crews that fly aircraft every day are far more concerned, and knowledgeable, about health and safety matters than the average Pentax user and we don't knowingly put ourselves at risk.

H2

More than you wanted to know, eh??
07-20-2012, 08:36 AM   #49
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
Original Poster
QuoteOriginally posted by pacerr Quote
As a matter of fact I do. I taught those systems for many years. NO TURBINE EXHAUST GASES ARE INVOLVED IN THE CABIN ENVIRONMENTAL AIR SOURCES!

In simple terms, a small jet turbine drives a separate compressor stage turbine that compresses and heats outside ambient air to 200-300 deg F. It's then passed through a de-compression stage to cool it to just above freezing. The two air sources are then mixed to produce thermostatically controlled, cabin and cargo compartment zone temperatures between about 40-80 deg F.

There's no reason not to regulate temperature to a healthy, comfortable level since the same environment is shared by the flight crew -- cargo or otherwise.

Note that the process lowers humidity to an unhealthy level. If there's not a load of sweaty, exhaling humans to re-humidify the air in passenger service (HEPA-class filtration is used), humidifiers are employed to satisfy crew health needs. Environmental systems are essentially identical in both passenger and cargo aircraft - one design suits all purposes.

The temperature issues are not with a normal aircraft in flight, but with unregulated cargo bay conditions on the ground in hot or freezing weather. Any environmental system failure in flight will soon have the aircraft on the ground.

If temperature and humidity aren't very well controlled in any aircraft, excessive condensation forms on the INSIDE of the aluminum hull. Over time that soaks the insulation, adds tons of weight, freezes/thaws, grows nasty fungus and causes really bad corrosion problems.

Myths and BS aside, if something happens to you or your belongings in flight it will be because of human failure or unanticipated mechanical failure, sort'a like havin' the UPS truck T-boned by a train; not an intentional design decision. The crews that fly aircraft every day are far more concerned, and knowledgeable, about health and safety matters than the average Pentax user and we don't knowingly put ourselves at risk.

H2

More than you wanted to know, eh??
Thanks. So there are additional turbines, other than the engines used for flight, dedicated to this process? Interesting. If all that is true then why the common references to fore and aft holds in commercial airliners having significant environmental differences to the point that if an animal is placed in the aft hold they can freeze to death? Are all those stories just myths?

07-20-2012, 08:49 AM   #50
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,758
QuoteOriginally posted by pacerr Quote
More than you wanted to know, eh??
Gotta love this forum!
07-20-2012, 10:14 AM   #51
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
Original Poster
Just an update. Amazon sent the replacement package Next Day AM delivery as a courtesy. Man, it looks like it has never been handled by human hands - it is PERFECT. I am at the office and slammed but will upload pictures of the new box unwrapping this evening. I am very happy with Amazon and how they have handled this matter.
07-20-2012, 11:01 AM   #52
Veteran Member
TenZ.NL's Avatar

Join Date: Feb 2012
Location: Below sealevel
Photos: Gallery | Albums
Posts: 1,100
Indeed handled very well. Congrats and cheers with your new glass.
07-20-2012, 11:47 AM   #53
Veteran Member
stormtech's Avatar

Join Date: Jan 2011
Location: In the boonies (NW Penna)
Photos: Gallery | Albums
Posts: 5,670
QuoteOriginally posted by Docrwm Quote
Just an update. Amazon sent the replacement package Next Day AM delivery as a courtesy. Man, it looks like it has never been handled by human hands - it is PERFECT. I am at the office and slammed but will upload pictures of the new box unwrapping this evening. I am very happy with Amazon and how they have handled this matter.
Impressive service for sure!

07-20-2012, 11:56 AM   #54
Loyal Site Supporter
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,910
QuoteOriginally posted by Docrwm Quote
. . . why the common references to fore and aft holds in commercial airliners having significant environmental differences to the point that if an animal is placed in the aft hold they can freeze to death? Are all those stories just myths?
No one intentionally operates a "public commercial conveyance" with apparently life threatening design flaws in this lawsuit prone age without criminal intent. But it costs nothing to perpetrate misunderstood or malicious information. And aviation has to be the most over-regulated industry ever devised.


Specifically which aircraft? In many cases a situation is misinterpreted owing to ignorance of the actual facts of an isolated incident and then spread as fact.

Example: in one specific version of a common passenger jet the auxiliary power unit (the l'il jet engine in the tail cone) which can provide alternate "bleed air" for engine starts and environmental conditioning only has provision for thermostatic control in the aft cargo compartment. It's intended to provide temperature control for sensitive cargo (flowers, pets, etc) when the aircraft's two main air conditioning/heating systems aren't supplied by the engine's "bleed air" supply on the ground -- a great convenience when loading cargo in the winter in Minneapolis for instance.

A reasonable suggestion that pets be loaded in the aft compartment during inclement conditions somehow became miss-interpreted in a loading manual such that it prohibited transporting pets in the forward compartment in that model aircraft even though both compartments are environmentally supplied by the same conditioned air source in-flight and no restrictions applied to similar aircraft.

One whiff of that escapes to the public rumor mill and "OMG, if they put Fifi-poo in the XXX cargo compartment she'll freeze to death". In fact both "pits" are ventilated and surrounded by the same conditioned, pressurized air used in the passenger cabin in flight. (And note that this particular example is the exact opposite of the situation cited.)

That manual and procedure was subsequently revised -- any bets as to when the public's gonna hear about that an' pass the word you no longer have to worry about frozen pup- sicles?

(I'm probably being reckless just introducing the technically correct term "bleed air" here. Compressed air is "bled off" from the compressor turbines in the engines for certain uses.) Martha, did ya hear 'em, the air suction "bleeds" them poor dogs in the cargo 'pits'. I could hear 'em squealin' again just now when the big wheels went down! )

We're gettin' well OT here. PM if ya have questions.

Last edited by pacerr; 07-20-2012 at 12:01 PM.
07-20-2012, 12:01 PM   #55
Loyal Site Supporter
Loyal Site Supporter
eddie1960's Avatar

Join Date: Aug 2010
Location: Toronto
Photos: Gallery | Albums
Posts: 12,273
QuoteOriginally posted by pacerr Quote
(I'm probably being reckless just introducing the technically correct term "bleed air" here. Compressed air is "bled off" from the compressor turbines in the engines for certain uses.) Martha, did ya hear 'em, the air suction "bleeds" them poor dogs in the cargo 'pits'. I could hear 'em squealin' again just now when the big wheels went down! )

.
LMAO - yep by this time next week it'll be a story in the onion


Informative post BTW
07-20-2012, 02:07 PM   #56
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
Original Poster
QuoteOriginally posted by pacerr Quote
No one intentionally operates a "public commercial conveyance" with apparently life threatening design flaws in this lawsuit prone age without criminal intent. But it costs nothing to perpetrate misunderstood or malicious information. And aviation has to be the most over-regulated industry ever devised.
............................
(I'm probably being reckless just introducing the technically correct term "bleed air" here. Compressed air is "bled off" from the compressor turbines in the engines for certain uses.) Martha, did ya hear 'em, the air suction "bleeds" them poor dogs in the cargo 'pits'. I could hear 'em squealin' again just now when the big wheels went down! )

We're gettin' well OT here. PM if ya have questions.
Thanks for the reply. Always glad to learn more. Why are the puppies bleeding in the air BTW
07-20-2012, 10:14 PM   #57
Site Supporter
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,663
QuoteOriginally posted by Docrwm Quote
Very strange take on it IMHO. As I said in the text, the first lens was DOA and the second was decentered. Lenses are not designed to take multiple slams that would be required to accordion TWO corrugated boxes nested inside each other.
I agree. When I was first getting into photography (over 40 years ago), the one standing piece of advice was to beware of any lens or camera that had ANY evidence of EVER being dropped.

In the case of your UPS shipments, it is pretty clear that your items were mishandled in transit. You paid good money for your item as well as a fee to have the items shipped by a reputable agent. The inner box should appear as it would if you had purchased it at the Adorama counter. The shipping box, likewise, should be in good condition with no evidence of misuse. The cost of gross abuse by the shipping company should be born by that company, not the you the customer.


Steve
07-20-2012, 10:16 PM   #58
Site Supporter
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,663
QuoteOriginally posted by Docrwm Quote
Exhaust gases are diverted
Huh? I thought those were what makes the plane go!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
box, boxes, k-mount, lens, lenses, pentax lens, slr lens, tamron
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax Full Frame Dream Crushed Today LFLee Pentax Full Frame 946 01-04-2013 09:07 AM
For Sale - Sold: Pentax AF200T Flash with original box FREE Shipping (CONUS) yyyzzz Sold Items 2 11-28-2011 10:41 PM
For Sale - Sold: SMC Pentax DA 18-55mm f3.5-5.6 AL Lens in Box -- Free Shipping wallyb Sold Items 2 02-15-2009 08:14 PM
Pentax K200D kit on Amazon $536 with free shipping after rebate (gold box trick) amirko Pentax DSLR Discussion 16 06-30-2008 05:06 AM
My Dream of a K20D, crushed..... Mr Hyde Pentax DSLR Discussion 10 04-10-2008 02:13 PM



All times are GMT -7. The time now is 11:05 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top