Fuel Burn Rates

[Scooter14]

Thanks, Rocker. We have EGT in the mighty Stratotanker and set N1 or Fuel Flows depending on your preference, but I now feel sufficiently caught up to the discussion.

[Guest Hoser]

Originally posted by Xtndr50boom:

This Q is more for BFM and Hoser:

Are fighter engines flown to destruction, or are they replaced at a certain hour timeframe? Me thinks a viper/single engine would go by time but you never know until you know, you know?

I'm not a maintainer, but I'm willing to bet the engines are not fly to fail. As for the single engine considerations, I think they they will only allow certain block's of F-16's across the pond / across the fence. IIRC, if an F-16 block ends in 0 (block 30,40,50) it has a GE engine. If it ends it a 2 (block 52), it has a PW Motor.

The real point I was trying to make, is based on my assumption from reading the previous posts, that crew airplanes spend a certain amount of time, arguing/deciding what is the appropriate TIT (I said TIT) at that particulr time. In fighters, we fly an airspeed and whatever power is needed to get there, then that's our power setting. If it takes min-AB to RTB at "morale speed" which is normally .9M as the limiting speed on the GBU-12 seeker cranium, then min-AB it is.

Hoser

[BFM this]

boom,

No clue, maybe Hoser's got something more.

I can tell you that as part of A-10 TOLD, if we don't get a certain expected fan speed on the rwy, the wheels never come up-->back to MX.

There is a system monitor that MX uses which I preflight for certain show-stopper codes, but they told us it tracks all sorts of parameters.

[Guest AirGuardian]

AF = "not fly to fail", Navy is more like it - I kid you not!!! Maybe they've changed, but we have are nitnoid inspecs still... former MX.

[Guest Xtndr50boom]

Hoser, back in the piston engine day the flight engineer (s) would hold back the pilot's airspeed to a more wimpy number to lessen the wear and tear on the engines; back then you only had a few hundred hours before engine teardown and overhaul. Maybe the spirit of that is still alive and well in alot of heavy crews. That or they're just fvckin @ssholes padding their airline applications by squeezing an extra .2 or .3 out of their flights

[Guest ELan]

I wouldn't say you have crews "arguing" about TIT settings. It became an FCIF in our unit, so that is why we do it. Plus, since we're Guard and we own the planes...it is our job to do our part. Maintenance does their job to keep our planes in tip top condition and it is only fair to the unit that we do our best to preserve the engines. I'm sure they aren't cheap and the Guard doesn't have money flowing out the ace...even with GWOT money...

[HerkDerka]

I disagree. I see every instructor I practically know with a different spin on TIT settings.

Since when does AD have money flowing into the Herk world? Last time I checked I fly a plane 10-20 years older than yours. And with a busted wingbox.

HD

[Guest ELan]

Sorry, poor choice of wording on my part. I wasn't trying to include AD, but I can see how it looks like that. Just trying to say that our unit is consistent on the madder, so there are no questions in the cockpit. Looks like AD is inconsistent and AC dependent...and that doesn't surprise me.

Oh, and last time I checked, I flew your model planes, until we gave our "10-20 years older" planes to AD (including your unit) with wingboxes that were NOT busted. That may have something to do with how the Guard flys there planes....hmmm.....seems to be a theme here.

Sorry man...had to...you just T'd it up for me and I couldn't pass it up....

[Scooter14]

How did PilotKD post from the future?

[BFM this]

OK, lets hear some data. I'll lead off:

Sioux city (UA232) wasn't a result of turbine wear from temps, it was an undetected hairline crack, the results of which are still calculated to be astronomical, but after the fact the mods to the hyd system were made nonetheless.

While I was in Okinawa, every SOP temp limit that came down the pike (down to 935 at one point) was an attempt to stem the flow of engines into the MX supply system, a system which gave those engines back at half the rate they went in. Made FMC rates kind of tough to make if everyone was flying around at "morale speed".

What we did fear was things like gearbox or prop failures, one of which occured in the unit I was in during a det to Brisbane.

Likewise, it sent a chill down everyone's spine on one flight I was on when the FE picked the scrabble board up off of the throttle quadrant, set it on my table and said: "OK, #3 gearbox oil pressure is 0, my checks are done, sir, lets go ahead and CAGE THREE" Yeah, there were chunks on the plug when we landed.

Someone who makes a living borescoping engines can refute me on this, but turbines, even ones that have been ridden hard (sts), don't typically frag.

[Hacker]

Originally posted by Xtndr50boom:

Hoser, back in the piston engine day the flight engineer (s) would hold back the pilot's airspeed to a more wimpy number to lessen the wear and tear on the engines; back then you only had a few hundred hours before engine teardown and overhaul.

This is still a hotly disputed topic even today. I'm currently "learning" to fly the B-25, and the use of reduced manifold pressure takeoffs is batted around frequently.

Interestingly, evidence from big piston engine rebuilders is that, over time, the reduced MP settings DO NOT lessen engine wear. Something about the less pressure on the top half of the piston as it goes through the power stroke (sts) contributes to more wear on the connecting rods (sts).

An interesting debate, and I'm amazed that even 50+ years later the merits of it are still disagreed on. I wonder if the same will be true of the turbine motors of today.

[Rocker]

Originally posted by Scooter14:

How did PilotKD post from the future?

Whoa! It's probably the Matrix.

[BFM this]

OK, reading through my above rants, I find them lacking one important item: a point.

That would be this: my ejection seat is not license to be ignorant or unnecc abusive of my airframe. Lack of an ejection seat is not designed to be extra motivation to learn minutia about various systems. If any multy place aviator thinks they are more motivated to know every nook and cranny of their airframe than I, I say BS. Airplanes do not routinely explode or fall apart. Stupid pilot tricks will always ruin your day, I agree.

If you wanted to wax philosophical about it, yes, your lack of handles means that you are expected to bring that airframe home or die trying. HVAA: High Value Air Asset. You don't come home means that a force multiplier just went away. (I'm cosidering airlift to be a ground-force multiplier) Really big deal. Me on the other hand, maybe I am supposed to press my mission or eject trying. My airframe doesn't come home, yeah that still sucks (esp for me :eek: )...

But I am way to inexperienced in this game to have my philosophy taken seriously anyway. That's the only thing I know for sure.

[Bergman]

Originally posted by Hacker:

I'm currently "learning" to fly the B-25, and the use of reduced manifold pressure takeoffs is batted around frequently.

Ok..you can't just throw THAT out there and not elaborate! I spent a few years during my misspent youth working on a B-25 in Burlington, WI, so would enjoy hearing what it takes to get to fly one (besides a sh1t-ton of cash...aka the commemorative air force).

How does it fly?!

[Hacker]

Originally posted by Bergman:

How does it fly?!

Like a dumptruck. Of course, as a pointy-nosed guy, I don't have a bunch of experience in any kind of bombers to compare it to. Interestingly, the B-25 is about the same size and weight as the F-15E, so there's a legit comparison there.

She's pretty heavy on the controls...trim is definitely your friend. Turns usually require both hands on the wheel, but if the banks are shallow you can do it with just one hand. The real trick with a big multi-engine radial airplane, though, is not the stick-and-rudder flying, it's managing the engines. Making sure they're running the appropriate manifold pressure and prop RPM means that you can't just b*tch-slap the throttles around like in a jet. You also have to play with the props to get them sync'd, otherwise the harmonics will really give you a headache (the prop tips are about 3 feet from your skull!).

Other than that, she flies very honestly. Very easy to take off, relatively easy to land (but to a fighter guy the landing attitude picture is pretty high up in the air). Vmc flying is avoided, since the Mitchell apparently likes to snap right over on her back when you get below Vmc with full power on one motor.

Of course, you can't really quantify how it feels to just fly this thing...to feel/hear those big radials, the smells, the sights. It's absolutely incredible...I feel extremely lucky and blessed. When you're flying around in a WW2 bomber, you get to see sh*t like this:

Things that don't just ordinarily happen every day to your average pilot!

Originally posted by Bergman:

what it takes to get to fly one (besides a sh1t-ton of cash...aka the commemorative air force).

Dumb luck! Just being in the right place and the right time with friends who have the financial means. The airplane is the flagship of Warbird Digest magazine, N3155G, "The Green Dragon".

[Guest PilotKD]

Originally posted by BFM this:

Why are "Heavy boys" more concerned about this when they will typically loose 25-33% of thier engines when one throws a blade whereas fighters will loose btw 50-100% of thiers.

Because throwing a blade tends to be a violent event which can take out 25-33% of our wing from shrapnel and possible fire. There's a little bit different mind set when you can't get out of the aircraft.