PW JT3C on Boeing 707

[bzn20]

Yes Jeff,It was a Danair 'plane with IAS on the fin.Dan air also had a joint company with Tradewinds called Tradedan.Although I think that was more to do with buying old "C" model 707's rather than opperating them.

[Jeff Jarvis]

Greetings!

Well, I guess we kind of hijacked Euge's thread with our discussion, so, apologies to you Euge!

Regards,

Jeff Jarvis

[David Hingtgen]

Just to bring this full circle, this is 4X-JYD, an original 707-120. With JT3C engines. Looks like a reverser cascade array to me. :)

Edited January 14, 2013 by David Hingtgen

[72linerlover]

Jeff, the news you brought are so interesting for all and there's no reason to apologies.

Thank to David Hingtgen for posting that photo. It will be my construction reference.

Thanks again to all gents that answered my question.

Regards

Euge

[Captoveur]

Be careful believing anything on the Airliners.net forums. That site has turned into all MSFS "captains" and 13 year olds

[Spokane-Modeller]

Be careful believing anything on the Airliners.net forums. That site has turned into all MSFS "captains" and 13 year olds

most of its like that anyway isnt it? I mean im pretty heavy into MSFS but unless i know what im talking about or know the correct answer i keep my mouth shut.

[72linerlover]

Please, excuse me if I reopen this old thread.

Is there some Boeing expert that can tell the difference between the two thrust reversers in the following pictures?

Photo1

Photo2

They should be both 707-121 (pan American).

In the pic from the front left is quite visible a grille, but in the other one from the bottom there is a sort of dark ring. Was it perhaps to be slid back when the reverser operated, thus uncovering an aperture?

Which between the two types came first or later?

T.i.a

Regards

Euge

[Jeff Jarvis]

Greetings!

I can't answer for sure, but I suspect that the second photo might have been a thrust reverser grille cover that slid back exposing the grille when reverse thrust was selected, and then was deleted after service experience showed it to be a maintenance headache and that it was not necessary for drag reduction anyway. I would say that the first photo showing the exposed grille became the norm after that. Note also that there is a flat blocker plate in the middle of the grille. That is put there to direct the reverse stream downward and upward out of the horizontal line of the engine intake so as to help prevent reingestion of the reverse exhaust gases which could cause intake flow disruptions with resultant surging and compressor stalling.

Notice that on the second photo if you look up on the forward part of the pylon at the turbocompressor hump on the #1 engine, there is no hole for heat exchanger exhaust as there is on the first photo showing the #2 engine. This is because the one on the #1 engine is a fake. There are never more than a max of three T/Cs on a 707, and often only two on small 707s (except small overwater 707s) or on the American 707-323B/C.

For some reason Boeing put fake T/C humps on the pure jet 707s for a more balanced look, but then did not on the fan powered models. You can spot the fake ones by looking for a heat exchanger hole on the left side of the hump. If there is no hole, it's a fake, generally on #1 and #4 or just #1.

Regards,

Jeff Jarvis

[72linerlover]

Thank you so much, Jeff.

So it make sense that the N707PA at the roll out was equipped with that "annular grille cover". - I'm lucky.

Thank you also for the considerations about the turbocompressors.

I was almost sure it was so, but your words are important.

Now it's up to me to do things right.

Regards

Euge