F-14s being retired...

[kach22i]

Originally posted by bell

How do they slow the air coming into the engine to subsonic speed if it's a straight intake shot?



Does the adjustible front hood lip (wedge intake - dips down) limit the amount of air coming in that much so that the air slows down when it expands? How about the air density, or is it just air pressure at that point?

Lets see, if you limit the volume of air in, it would slow down, right?

Just the opposite as narrowing a venturi or water hose in that it increases pressure, right?

[Eric 951]

Originally posted by rcecale
As of 2000 it was estimated that only 40 of the 132 F-4Ds, 177 F-4Es and 16 RF-4E. Phantoms delivered before 1979 remained in service. At that time, approximately 45 of the 169 F-5E/Fs delivered are still flying, while perhaps 20 F-14A Tomcats of the 79 initially delivered were airworthy. Another 30 F-4s, 30 F-5s and 35 F-14s have been cannibalized for spare parts. One report suggested that the IRIAF can get no more than seven F-14s airborne at any one time. Iran claims to have fitted F-14s with I-Hawk missiles adapted to the air-to-air role.


GlobalSecurity

Randy

paste?

[scottmandue]

I know nothing.... however one of my teachers was an F-14 pilot and he told me while he loved the old tomcat they were high maintenance and required a constant flow of new parts to keep them in the air.
FWIW

[scottmandue]

Less fighting...
(I know... dream on...)
More pictures!

[IROC]

Originally posted by scottmandue
I know nothing.... however one of my teachers was an F-14 pilot and he told me while he loved the old tomcat they were high maintenance and required a constant flow of new parts to keep them in the air.
FWIW

The article I read said 40 hrs of maintenance for every 1 hour of flight.

Mike

[Don Plumley]

Originally posted by kach22i
How do they slow the air coming into the engine to subsonic speed if it's a straight intake shot?



Does the adjustible front hood lip (wedge intake - dips down) limit the amount of air coming in that much so that the air slows down when it expands? How about the air density, or is it just air pressure at that point?

Lets see, if you limit the volume of air in, it would slow down, right?

Just the opposite as narrowing a venturi or water hose in that it increases pressure, right?

There are ramps on the top of the inlet - look at the sides of the inlet and you can see where the ramp extends downward. Here's a more detailed explanation:

The intakes are of multi-ramp wedge configuration and offer a straight path for the air entering the engines. Each intake has a pair of adjustable ramps attached to the upper part of the inner intake. Hydraulic actuators in the upper part of the intake adjust the positions of the first and second ramps in the upper surface of the inlet and of the diffuser ramp located further aft, reducing the inlet air to subsonic velocity before admitting it to the engine. A gap between the back edge of the second ramp and the leading edge of the diffuser ramp allows bleed air to escape from the inlet, passing overboard via a bleed-air door in the outer surface of the inlet. The inlet ramps are under the automatic control of a computer, which calculates the optimal position for the ramps based on engine speed, air temperature, air pressure, and angle of attack. At supersonic speeds, the hinged panels narrow down the throat area while diverting the excess airflow out of the ducts through aft-facing spill doors at the top of the intakes. At low speeds (especially during takeoff) when more engine air is needed, this airflow is reversed and extra air is sucked in.

[MFAFF]

Kach,

Don's post and quote are spot on...

The ramps serve to create the standing pressure waves that slow the supersonic airflwo down before it reaches the engine face.

All Western turbofans and jets need stable subsonic airflow to the first compressor stage....perhaps there are some that are not as well known...its known that the MIG 25 engines use a transonic first stage...

The ramps creatre standing pressure wave in the inlet which both slows and compresses the air prior to reaching the entrance.... this provides both the right type of air for the engine...and a handy increase in pressure..and hence engine thrust..

Especially for the poor F-14A.. with its TF30s...much better with the B and D models.. (the D model ended its career with the ramps fixed to reduce maintenance demands...it was limited to M1.88, hardly a real handicap).

Its shame its gone...it truely was the most powerful aircraft on a carrier....

[fastpat]

Originally posted by IROC
The article I read said 40 hrs of maintenance for every 1 hour of flight.

Mike

That's rather typical of high performance fixed wing aircraft. Helicopters require more, much more.

[air-cool-me]

Originally posted by kach22i
How do they slow the air coming into the engine to subsonic speed if it's a straight intake shot?
]?

like MFAFF said...Im pretty sure a normal shockwave would be created at the start of the duct.... reducing the speed of the air to below M-1.

if M-1 air hit the fan blades a bunch of normal shockwaves would develop on the blades... creating vibrations and many other problems
(or at leasts thats what my text book says )

[Seahawk]

Originally posted by fastpat
That's rather typical of high performance fixed wing aircraft. Helicopters require more, much more.

Not true at all. It really depends on the type, age and condition of the jet or helo. Having been both a detachment maintenance officer and a squadron MO (collateral duties in addition to flying) as well as a maintenance test pilot for years, I might have some insight here.

In addition, all new aircraft designs and upgrades to exiting aircraft (including avionics) have been done with maintenance and reliability in mind. We call it, "design to maintainer" and ensure ease of maintenance (including HSI) and repair.
Having been working at building aircraft for the last 15 years, I may have some insight here as well.

[IROC]

Originally posted by fastpat
That's rather typical of high performance fixed wing aircraft. Helicopters require more, much more.

Well, FWIW the article also stated that the F/A-18s that are replacing the F-14s only required half as much...

Mike

[Eric 951]

so, pastey is wrong 3 times in the same thread. lordy!


BTW, I was always a fan of the Phantom F-4.

[IROC]

Originally posted by Eric 951
BTW, I was always a fan of the Phantom F-4.

Me too. I love all the F-4s...Phantoms and Corsairs. We should have a whole thread on WW2 warbirds. I love those things...

Mike

[kach22i]

Because we have a bunch of experts on this thread, I have a Off-Topic question or request for you all.

Help me find an enclosed ducted fan drive unit which can be powered by an automobile engine (via belt or gear box/driveshaft), 180 hp to 800 hp power range (500 hp avg).

Reference thread:
http://www.hoverclubofamerica.org/forum/index.php?showtopic=913

[fastpat]

Originally posted by Seahawk
Not true at all. It really depends on the type, age and condition of the jet or helo. Having been both a detachment maintenance officer and a squadron MO (collateral duties in addition to flying) as well as a maintenance test pilot for years, I might have some insight here.

Since I have no experience with the same aircraft you do, I can't reply directly. In my old attack aviation unit I'd guesstimate that about 200 hours of maintenance for every flight hour was the norm for the Apache's. The Blackhawks were significantly less, probably about half that or less. Of course, the OH-58's were relatively minor in comparison, probably around 20-30 hours for every flight hour. That's all levels of maintenance including routine inspections and 25, 50, and 100 hour mandatory maintenance; together with unscheduled maintenance.

In addition, all new aircraft designs and upgrades to exiting aircraft (including avionics) have been done with maintenance and reliability in mind. We call it, "design to maintainer" and ensure ease of maintenance (including HSI) and repair.
Having been working at building aircraft for the last 15 years, I may have some insight here as well.

Yes, and I have seen an aircraft with all the weapons systems redlined for maintenance listed as available for combat because it could fly. Not often, but it can and does happen.

I'm happy to hear that the Navy has such a high availability rate, though, that means we can do with fewer aircraft in the future.

[fastpat]

Originally posted by Noah
Pat, where has Iran gotten parts for its F-14's since 1979? "All" of them are still "fully operational" -- after 27 years of no parts?

One of the primary sources for combat aircraft parts for Iran, particularly during the Iran-Iraq War, was Israel. Don't tell me you didn't know that, Noah.

Today, Iran makes most of their own parts.

[rcecale]

Originally posted by Eric 951
so, pastey is wrong 3 times in the same thread. lordy!

It was as easy as shootin' fish in a barrel!

BTW, I was always a fan of the Phantom F-4.

F-4's 4-ever, baby!!!

Randy

[Danimal16]

Lovin' F4's and F14's is an acquired taste, kinda the way you love women, big and brassy and lots of red curly hair.

Used to watch the big Phantom's at El Toro as a little kid with my dad. Could sit there for hours. Do you suspect that it shaped my desire for those brassy beauties?

[fastpat]

Originally posted by Danimal16
Lovin' F4's and F14's is an acquired taste, kinda the way you love women, big and brassy and lots of red curly hair.

Used to watch the big Phantom's at El Toro as a little kid with my dad. Could sit there for hours. Do you suspect that it shaped my desire for those brassy beauties?

Only if your redhead looks like a rhinoceros right below that hair.

[Danimal16]

And I suppose you think an A6 was ugly as well?

Originally posted by fastpat
Only if your redhead looks like a rhinoceros right below that hair.