A little F-15C AFM update - 7 December 2013

[VapoR]

It can't show you the details.

 

Get ready to re-learn how you roll a plane for example ...

 

How is this different from the AFM aircraft we have already?

[kontiuka]

Did he really say that it will be included with 1.2.8? ;)

I don't think that was actually said.

[GGTharos]

From the AFM standpoint, it isn't. From the 'what the plane does' standpoint, it's not quite the same as the others. The principles of flight and handling remain the same, the details start showing some differences though, which is what AFM is all about.

 

How is this different from the AFM aircraft we have already?

[upupandaway]

How is this different from the AFM aircraft we have already?

 

It´s gonna be so awesome that you have to be careful not to blow your mind in the process of rolling that plane...

 

I hope it will be in 1.2.8 though... :)

[Raven68]

this project will not be ready in time to be released with the 1.2.7 update

It's wide open folks. It's kinda like the birth of newborn! :) Dont know when it's coming... Edited December 9, 2013 by Raven68

[diveplane]

is that the system which tells/warns you: over-g, over-g, over-g ? :)

and i hope that team will add/correct the intake+diffuser ramps and nozzle animations whit real squealing/whimpering noises for both when works

 

nozzle noises

 

startup intake drop noises

 

hydraulic actuators, some reason f15s make a high whine

[KillarZ]

Didn't want to start a new thread about this so quick question.

 

If I buy FC3 within the next coming weeks will I automatically get the f-15c and su-27 AFMs when they come out?

[joey45]

You will get all the updates.

[GeorgeLKMT]

AFM and all the other updates related to FC3 aircraft will be there no matter when you buy it.

[KillarZ]

You will get all the updates.

 

AFM and all the other updates related to FC3 aircraft will be there no matter when you buy it.

 

OK thanks. Good to know.

[Psyrixx]

If I buy FC3 within the next coming weeks will I automatically get the f-15c and su-27 AFMs when they come out?

 

Keep in mind that in order to install FC3 you must own Lock On or a previous Flaming Cliffs title. Also, FC3 is not (officially) transferrable to the Steam version of DCS World. Stand alone aircraft have already been released for the A-10A and Su-25, and it stands to reason that the same will be true of the F-15 and Su27 once the AFMs are completed.

 

The stand alone versions do not require Lock On or a previous Flaming Cliffs title, and will (likely, if the module releases up to this point are any indication) be fully transferable to/from the Steam version.

 

:)

[Rainmaker]

Not sure what do you mean about intake sound during start up, could you clarify? AFAIK, intakes are Hydraulically driven/operated and the only sound i hear is the JFS coupling and decoupling ( to be precise is the CGB/JFS combo, I know some one will have to bring that up, but anyway).

 

 

What he said

[NRG-Vampire]

Not sure what do you mean about intake sound during start up, could you clarify? AFAIK, intakes are Hydraulically driven/operated and the only sound i hear is the JFS coupling and decoupling ( to be precise is the CGB/JFS combo, I know some one will have to bring that up, but anyway).

 

hydraulic actuators, some reason f15s make a high whine

 

exactly as diveplane wrote

 

sure we cant hear the noise of the actuator while its adjusting the inlet much more slower in the air to the aoa, but we can hear at the startup

i can hear the separate noise when the inlet drops down at startup - and thats not the noise of the jfs

 

here are two videos more with that noise

in first video the japanese pilot started almost same time two engines (left engine only 1 second after the right engine 1:39 and 1:40) because of the sacramble

we cant see the right inlet drop but we can hear it - just before the left inlet drops down with another whine

 

Edited December 10, 2013 by NRG-Vampire

[Snoopy]

And out come the wiki and youtube experts :doh:

 

Sorry if this is harsh but have had to deal with it concerning the A-10 for 3 years now I guess it'll be the F-15. Luckily for me the F-15 is the other air frame I've worked (3 years depot level maintenance) through my USAF and civil service career.

 

Simply put, both you and diveplane are wrong, the sound your talking about in both videos is the JFS unloading and shutting down (after #1 starts). Real world F-15s start the #2 engine first, then we pull the gear pins. Then on to #1.

 

exactly as diveplane wrote

 

sure we cant hear the noise of the actuator while its adjusting the inlet much more slower in the air to the aoa, but we can hear at the startup

i can hear the separate noise when the inlet drops down at startup - and thats not the noise of the jfs

 

here are two videos more with that noise

in first video the japanese pilot started almost same time two engines (left engine only 1 second after the right engine 1:39 and 1:40) because of the sacramble

we cant see the right inlet drop but we can hear it - just before the left inlet drops down with another whine

 

Edited December 10, 2013 by Snoopy

[NRG-Vampire]

as the engine spins up past 56% rpm the right generator comes on-line and the right engine intake ramp - which has been locked in the full-up position - slams to the full down position

 

the jfs automatically shuts down - only one time - when the second -left - engine reaches approx. 50% rpm

 

sorry but that's why it cant be the noise of the jfs because we can hear that noise twice exactly when both inlets drop/slam down - of course not the same time: usually left engine started 1 minute later than right engine

Edited December 10, 2013 by NRG-Vampire

[Rainmaker]

exactly as diveplane wrote

 

sure we cant hear the noise of the actuator while its adjusting the inlet much more slower in the air to the aoa, but we can hear at the startup

i can hear the separate noise when the inlet drops down at startup - and thats not the noise of the jfs

 

here are two videos more with that noise

in first video the japanese pilot started almost same time two engines (left engine only 1 second after the right engine 1:39 and 1:40) because of the sacramble

we cant see the right inlet drop but we can hear it - just before the left inlet drops down with another whine

 

 

 

As Paul noted, you guys have it wrong.

 

And the F-15 cannot start engines at the same time, they are electrically locked out so as only one engine is started at a time.

 

You also will never hear the inlet ramp actuators moving the ramps. The inlet noise you hear is mearly a change from the direction that the sound comes from relative to your ear/mic from from a video recorder, etc, much the same as if you walk from front to back behind the intakes. If you were to stand infront or inbetween there is no discernable difference.

 

They also do not schedule inflight based on AoA, there are a number of other factors involved in their movement.

[Rainmaker]

as the engine spins up past 56% rpm the right generator comes on-line and the right engine intake ramp - which has been locked in the full-up position - slams to the full down position

 

the jfs automatically shuts down - only one time - when the second -left - engine reaches approx. 50% rpm

 

sorry but that's why it cant be the noise of the jfs because we can hear that noise twice exactly when both inlets drop/slam down - of course not the same time: usually left engine started 1 minute later than right engine

 

 

Look, the JFS alternates between two speeds during both engagements. It is the JFS disengagement and speed reducing to idle that you are hearing.

[cacti4-6]

nice...can we have it now?

[Snoopy]

as the engine spins up past 56% rpm the right generator comes on-line and the right engine intake ramp - which has been locked in the full-up position - slams to the full down position

 

the jfs automatically shuts down - only one time - when the second -left - engine reaches approx. 50% rpm

 

sorry but that's why it cant be the noise of the jfs because we can hear that noise twice exactly when both inlets drop/slam down - of course not the same time: usually left engine started 1 minute later than right engine

 

So you have first hand experiance and knowledge because you are or have been an F-15 crew chief? If not please stop.

Edited December 10, 2013 by Snoopy

[NRG-Vampire]

Look, the JFS alternates between two speeds during both engagements. It is the JFS disengagement and speed reducing to idle that you are hearing.

 

i cant believe you guys saying those huge surface inlets move so quickly by huge and strong actuators silently

that inlet actuator noise is too short, it cant be the jfs disengagement, i dont think the jfs will drop down the rpm to idle in three seconds

i dont say that's the same noise like nozzle open/close but similar

lower tone and longer but similar

 

and i stop now :)

[Rainmaker]

i cant believe you guys saying those huge surface inlets move so quickly by huge and strong actuators silently

that inlet actuator noise is too short, it cant be the jfs disengagement, i dont think the jfs will drop down the rpm to idle in three seconds

i dont say that's the same noise like nozzle open/close but similar

lower tone and longer but similar

 

 

Believe what you want, but what you currently believe is wrong. I assume you have no personal experience? Well Paul apparently has a few years on 15s, and I have 14 years. So...believe what you want, but neither of us are pulling this out of thin air. The ramps do not have to cycle during engine start either. As a matter of fact, they are normally not cycled during maintenance runs. Same noises that you say are present, are heard regardless of wheather the ramps are cycled or not.

[NRG-Vampire]

And the F-15 cannot start engines at the same time, they are electrically locked out so as only one engine is started at a time.

 

ok, gotha - exactly that was strange to me on that first japanese video

i watched again and now i see - hear:) - the first right ramp came down at 0:50 just before the man run to the nose gear and not at 1:39

 

by the way: could you -would you mind- link/post a video (if there is) when the pilot use/check the inlet ramps auto/emergency modes when engine is running at idle without the jfs noise ? ;)

 

They also do not schedule inflight based on AoA, there are a number of other factors involved in their movement.

 

of course, the air inlet controller adjusts the inlet position to optimal but as we see that's mainly parallel to the airflow - maybe except only when flaps/gears are down for takeoff and landing - insn't it ?

Edited December 10, 2013 by NRG-Vampire

[Rainmaker]

ok, gotha - exactly that was strange to me on that first japanese video

i watched again and now i see - hear:) - the first right ramp came down at 0:50 just before the man run to the nose gear and not at 1:39

 

by the way: could you -would you mind- link/post a video (if there is) when the pilot use/check the inlet ramps auto/emergency modes when engine is running at idle without the jfs noise ? ;)

 

 

 

of course, the air inlet controller adjusts the inlet position to optimal but as we see that's mainly parallel to the airflow - maybe except only when flaps/gears are down for takeoff and landing - insn't it ?

 

Pilots will rarely have a need to ever have the switch out of Auto. I tried looking for a maintenance run that included engine start earlier but could not find one.

 

The inlet ramps are actually composed of a few different ramp actuators, there are more than just the first ramp that you primarily see. They all work to schedule airflow. The ramps can will work to limit/increase airflow based on a bunch of different factors, so no, they do not always follow or stay with the primary flight direction. The ramps are also tied to the WoW switches, so no, not based on the gear but based on a weight on wheels condition.

[mvsgas]

NRG-Vampire

Both Paul and Rainmaker have been working the F-15, I know that for a fact. They are telling you the truth. What I think you are hearing is the Central Gear Box (CGB) winding down. To starts the engine, the CGB extends into the AMAD to turn it, which then turn the engine through a PTO shaft. That sound, is just the CGB disconnecting and winding down so it can be ready to engage the next AMAD.

 

Some info:

Engine Start System

The F-15C/D engine start system (figs. 19-1 and 19-2) is comprised of a Jet

Fuel Starter (JFS), Central Gear Box (CGB), the left and right Airframe

Mounted Accessory Drive (AMAD), related components and indicators.

The JFS is a small jet engine mounted forward of the engines on the aircraft

centerline, and is the only method of starting the engines.

19.1. The JFS is a turbine engine consisting of a gas generator and power

turbine, which is mounted to the CGB by a V-band clamp, and also mounted

to the airframe by two shock-dampening mounts at the 10 and 2 o’clock

position on the JFS exhaust. The JFS uses aircraft fuel for combustion, and

electrical power for ignition is supplied by a permanent magnet generator

(PMG). JFS lubrication is supplied by the CGB through transfer tubes at the

JFS/CGB interface. Power to start the JFS comes froma hydraulic start

motor and two pressure accumulators. The accumulators are pressurized by

utility hydraulic pressure and nitrogen, and each accumulator has a capacity

of 215 cubic inches. When hydraulic pressure is unavailable, the

accumulators can be pressurized by using a manual pump located inside

access door 88L. The JFS air intake is located on access door 94, and JFS

exhaust is ducted through the lower moldline at fuselage station 680.00.

During JFS operation, the JFS compartment is cooled by air pulled in

through the CGB inlets and vented out two openings in access door 94.

During all other times, the JFS compartment is cooled by air pulled through

a lower moldline screen aft of the inlets and vented out through an upper

surface moldline opening at fuselage station 680.00.

19.2. The CGB drives the PMG which supplies electrical power for JFS

ignition; drives the JFS gas generator during the JFS start cycle; and

transfers power to each AMAD for engine starting. The CGB, located inside

access door 83, is attached to the JFS by a V-band clamp and to the airframe

by a top link mount and two lower bearing mounts, and provides mounts for

the PMG and hydraulic start motor. During JFS operation, the hydraulic

start motor uses accumulator pressure to operate the CGB, which turns the

PMG to provide electrical power for ignition, and turns the JFS for starting.

Once the JFS is operating fully, poweris transferred to the AMAD through

the use of a multiple disc clutch and isolation decouplers by lifting the finger

lift on each throttle.

134

19.3. The left and right AMAD are connected to their respective engine by a

driveshaft,and transmit JFS power from the CGB to the engines for engine

starting. After engines are operating, they transmit engine power to

hydraulic pumps and generators for accessory operation.The L and R

AMAD, located inside access door 85L/Rrespectively, are attached to the

airframeby an upper mount and two lower bearing mounts. Each AMAD

provides a mount for two hydraulic pumps (one power control and one

utility), and an Integrated Drive Generator (IDG). Each AMAD is equipped

with an integral lubrication systemwith aircraft mounted heat exchangers

for oil cooling. Each lubrication systemcontains a 25 micron oil filter with

a pressure differential indicator in the filter housing. The left AMAD can be

disconnected fromthe engine for use in limited duty mode by using a

manual decoupler. The limited duty modeis used to provide electrical and

hydraulic power for 20MM ammunition loading.

 

http://www.f-15e.info/joomla/en/technology/engines/97-jet-fuel-starter

 

Is it silent? No, Rain and Paul are not saying that, but the only way you would hear it is by running a electrical powered hydraulic mule ( which I only saw one in 15 years in the USAF)

 

Anyway, just my opinion. moving on.

Paul, rain, thanks for the input guys.

Edited December 10, 2013 by mvsgas

[Rainmaker]

NRG-Vampire

Is it silent? No, Rain and Paul are not saying that, but the only way you would hear it is by running a electrical powered hydraulic mule ( which I only saw one in 15 years in the USAF)

 

Reallly?!?

We have them all over the place here. :)

Plug into the wall outlets in the hanger. But even then, you only hear the "clunk" of the ramps as they hit the stops and the locks engage.

 

But...back on topic.

 

Now make that alpha limiter in the FM go away... :)