BeechTalk - BT - Questions on the F-15 (Ben C)

Username Protected · **Posted:** 10 Jul 2015, 18:25

Username Protected wrote:

That was also the approximate profile used operationally in the F-15 when setting up to shoot an AIM-7 at a 'high/fast flyer' such as the Mig-25.

Doug

I've never seen that. Did we do that operationally? Maybe before I started flying it in 2000. I've never actually flown the profile. Can't see it fitting any tactical scenario apart from point defense but you wouldn't be going after a Foxbat for point defense (no bombs). Hmm. Interesting though.

Username Protected · **Posted:** 10 Jul 2015, 19:04

This was a fun read from foxtrot alpha
Interviewing Lt. Col. Fred "Spanky" Clifton on the f-16, f-15 and mig-29

Username Protected · **Posted:** 10 Jul 2015, 19:32

Username Protected wrote:

I've never seen that. Did we do that operationally? Maybe before I started flying it in 2000. I've never actually flown the profile. Can't see it fitting any tactical scenario apart from point defense but you wouldn't be going after a Foxbat for point defense (no bombs). Hmm. Interesting though.

You may not have flown a "full blown" Rutowski climb, but I'll wager you've unloaded to get through the transonic region quickly (especially if draggy) when you've wanted to rapidly gain smash.

And that's all the RC really is--a way to quickly transition the region of highest drag.
You weren't snoozing in the after-lunch aero class, were you? :cheers:

Username Protected · **Posted:** 10 Jul 2015, 20:22

Username Protected wrote:

That was also the approximate profile used operationally in the F-15 when setting up to shoot an AIM-7 at a 'high/fast flyer' such as the Mig-25.

Doug

I've never seen that. Did we do that operationally? Maybe before I started flying it in 2000. I've never actually flown the profile. Can't see it fitting any tactical scenario apart from point defense but you wouldn't be going after a Foxbat for point defense (no bombs). Hmm. Interesting though.

Username Protected · **Posted:** 10 Jul 2015, 21:05

Doug-- Very nice.. Hope you are well. Tim

Username Protected · **Posted:** 10 Jul 2015, 22:09

Username Protected wrote:

Regarding the time to climb, I understand the numbers I wrote was an extreme case that is not real world. What is time to climb all in full fuel and full weapons.

I don't recall the numbers for a full load but we used to do a vertical climb in the training configuration (one full centerline tank and a training missile) when we gave incentive rides. The profile was AB takeoff and hug the runway to just before the departure end then a 4G pull to the vertical still in AB. We had to stay below FL180 because the pax in back usually didn't have an altitude card. We'd roll off at 17,500 directly over the runway still going 400 knots or a little less depending on temperature. This was at Eglin so sea level takeoff.

I did the Rutowski climb once in the Eagle. I was working late one Friday (everyone else was in the bar) and maintenance needed a post-maintenance test flight on an aircraft. They would lose lots of points on their stats if they waited until Monday so I hopped in the jet and tried out the profile. The jet was completely clean - it didn't even have pylons! I ended up at 54,000 feet going Mach 2.0. I didn't time the climb but the whole flight lasted exactly 20 minutes including a long idle glide back to the field. I landed just above min fuel.

FWIW, the F-15A was the nicest flying airplane I've flown to date. The performance was great but the flight controls were even better. It was the perfect blend of solid stability and incredibly light and responsive control. The airplane didn't have a mean bone in its body and would do exactly what you told it to do at any airspeed from Mach 2 down to the peg on the ASI. Man, I miss those days!

Edited to add: If the numbers sound a little off to the current Eagle jocks, bear in mind that 1) these were light F-15As with the original F-100 engines and the engines were de-tuned in a misguided attempt to improve the maintenance stats and 2) most of the numbers are from memory and those memories are over 30 years old!

Username Protected · **Posted:** 10 Jul 2015, 23:43

Username Protected wrote:

Regarding the time to climb, I understand the numbers I wrote was an extreme case that is not real world. What is time to climb all in full fuel and full weapons.

I don't recall the numbers for a full load but we used to do a vertical climb in the training configuration (one full centerline tank and a training missile) when we gave incentive rides. The profile was AB takeoff and hug the runway to just before the departure end then a 4G pull to the vertical still in AB. We had to stay below FL180 because the pax in back usually didn't have an altitude card. We'd roll off at 17,500 directly over the runway still going 400 knots or a little less depending on temperature. This was at Eglin so sea level takeoff.

I did the Rutowski climb once in the Eagle. I was working late one Friday (everyone else was in the bar) and maintenance needed a post-maintenance test flight on an aircraft. They would lose lots of points on their stats if they waited until Monday so I hopped in the jet and tried out the profile. The jet was completely clean - it didn't even have pylons! I ended up at 54,000 feet going Mach 2.0. I didn't time the climb but the whole flight lasted exactly 20 minutes including a long idle glide back to the field. I landed just above min fuel.

FWIW, the F-15A was the nicest flying airplane I've flown to date. The performance was great but the flight controls were even better. It was the perfect blend of solid stability and incredibly light and responsive control. The airplane didn't have a mean bone in its body and would do exactly what you told it to do at any airspeed from Mach 2 down to the peg on the ASI. Man, I miss those days!

Edited to add: If the numbers sound a little off to the current Eagle jocks, bear in mind that 1) these were light F-15As with the original F-100 engines and the engines were de-tuned in a misguided attempt to improve the maintenance stats and 2) most of the numbers are from memory and those memories are over 30 years old!

Username Protected · **Posted:** 11 Jul 2015, 07:31

Ok yes the unload to get through the barrier but the Streak Eagle profile was an Immelmann from takeoff and some sort of corkscrew climb deal with multiple level offs. I guess I was thinking the full profile.

We've actually updated our profile again. Some guys did a bunch of testing a few years ago, if we have a true long range commit we'll bunt to get M1.2 and climb there to the 40's then shallow the climb and usually get to the high 40's at M1.4+. Gives some good smash to the amraam!

Username Protected · **Posted:** 13 Jul 2015, 09:39

In the video, they show the altitude above 103,000'. Did the engine flame out? Are the flight controls effective at that altitude? It makes me think of the problems Chuck Yeager had with the F104 at that altitude.

Vince

Username Protected · **Posted:** 13 Jul 2015, 12:50

Can an F-15 fly supersonic without afterburner?

Username Protected · **Posted:** 13 Jul 2015, 16:55

Username Protected wrote:

Can an F-15 fly supersonic without afterburner?

Nope, not in level flight. The F-15 would need either afterburner or a steep descent to go supersonic.

"Supercruise", i.e. mil-power supersonic cruise capability was one of the RFP (Request for Proposal) requirements for the F-22 back in 1986 when they were soliciting bids for the program. Not sure if they ever lived up to that requirement.

Doug

Username Protected · **Posted:** 13 Jul 2015, 21:47

Username Protected wrote:

Nope, not in level flight. The F-15 would need either afterburner or a steep descent to go supersonic.

Interesting. I can, however, confirm that an absolutely clean (i.e. without even inboard pylons) F-4D would go (just) supersonic in Mil in level flight at 7,000', and I'd guess an RF-4C would have have done slightly better.

Dick

Username Protected · **Posted:** 14 Jul 2015, 08:54

Username Protected wrote:

Can an F-15 fly supersonic without afterburner?

Nope, not in level flight. The F-15 would need either afterburner or a steep descent to go supersonic.

"Supercruise", i.e. mil-power supersonic cruise capability was one of the RFP (Request for Proposal) requirements for the F-22 back in 1986 when they were soliciting bids for the program. Not sure if they ever lived up to that requirement.

Doug

Username Protected · **Posted:** 14 Jul 2015, 09:37

Now this is what "Brand X" should be all about . . .

Great topic and even better responses.

Username Protected · **Posted:** 14 Jul 2015, 23:17

Username Protected wrote:

Here are my opinionated (and biased) answers to your questions:

They have a radar so powerful they can pickup aircraft well beyond visual range and in many cases tell the pilot what model aircraft it is.
Yes, this is true.

The first aircraft to shoot down satellites.
Yes, this was true - but only once (Sep 85). During the Reagan years, the Anti-Satellite (ASAT) program was started to enable such an operational capability, but was later scrapped as technical problems and costs increased.

The MIG-25 was a big reason the F -15 was created.
False. The Mig-25 (Foxbat) was designed primarily to shoot down the B-70 Valkyrie bomber.

They say it has not been shot down . Ever.
Maybe true, not sure.

17 seconds after takeoff it is supersonic, 3 minutes later it is flying at 98,000 feet.
Is true, but only for rare (non-operational) cases. These numbers are probably from the Streak Eagle program - Winter 1975 at Grand Forks AFB, ND. This test was done as a public relations/marketing event to show the capabilities of the F-15. Was done at sub-zero temperatures and at ultra-light weights using a Rutowski climb profile. All of which did not represent operational parameters.

It is still in production.
True. Still in production, but planned to end in 2019.

It has the best power to weight. Still better than the F-22.
The F-15's published thrust/weight ratio is 1.07 whereas that of the F-22 is 1.08. Really pretty meaningless since this doesn't reflect the operational weight due to armament nor does it include the aircrafts' significantly different drag coefficients. Finally, thrut/weight ratio is a minor player these days whereas weaponry, defensive avionics/stealth, and ICC (integrated command/control) play much more significant roles than pure performance.

It is 10 times less money than an F-22
Meaningless statement considering the "cost" of military planes are usually frozen at the year of the first buy lot and thus don't reflect the rate of inflation for future years. Furthermore, the published cost per plane usually includes all the fixed sunk costs of design and development, not the actual variable cost of production. Furthermore, these numbers can be skewed when training costs and spare parts costs are attached to the price. Basically though, acquisition costs of new aircraft exponentially increases.

It seems that the F-15 is chosen over F-22 most of the time. They didn't say that that is my take on it. The F-15 was phenomenal plane in its time. It clearly outshone its predecessor, the F-4, in every category - handling qualities, performance, systems, etc. The F-22, however, is even more capable (so I'm told), but obviously much more expensive.

Doug

Flagged it with a like, and I'm sure you are right about the f22... But I still wish I could fly one