Anyone know anything about T-6As?

[Viggen 644]

Well, I got an email yesterday from my Civil Air Patrol National Activity I'll be taking in July at Columbus AFB that includes some .pdfs. Among them are the Boldface and Ops limits for the Texan II. Don't suppose any of you guys could help me out with what some of these numbers and abbreviations mean could you?

[DWCAce 19]

Get in contact with Jrz, he's flying them @ ENJJPT.

[FastCargo 412]

Yep, Jrz is full in the middle of ENJJPT, he'll know better than anyone.

 

Hmmm...setup for a T-6 ride...not too shabby. Better than a T-1 for sure...

 

FC

[+Typhoid 231]

if you would like someone to translate the meanings - put up what your question is. No doubt several here could tell you what they mean.

[Viggen 644]

That's right Jrz is flying them.

 

Won't be getting a ride in a T-6. Just some time in the simulator. And I'll be lucky if I get a ride in the T-1. Ah well, atleast I'll get a "Hero Shot" on a T-38.

 

As for the meanings/questions....there's a list...

 

From the Boldface Emergency Procedures page:

 

PCL

Intercept ELP

PMU

 

From the Ops Limits page:

 

Maximum ITT

Maximum Np

Maximum N1

Symmetric Acceleration Limit

Asymmetric Acceleration Limit (These I know are G limits but I don't understand what the symmetric and asymmetric refer to in this case)

Edited May 11, 2009 by JA 37 Viggen

[FastCargo 412]

Couldn't tell you the Boldface stuff...looks A/C specific.

 

However, some of the other stuff:

 

Maximum ITT - Don't know...maybe Max Internal Turbine Temp?

Maximum Np - Max Prop RPM?

Maximum N1 - Max Turbine RPM...most jet powered aircraft have something similiar...though a turbofan may have N1, N2, possibly even an N3.

Symmetric and Asymmetric Acceleration Limits - Basically G limits, if pulling straight back (like a loop) or pulling while rolling (like a barrel roll).

 

FC

[Viggen 644]

Well there's a good start. I'll PM Jrz for the Boldface.

 

The email said that right now we really just have to know the numbers, but I'd rather know what the abbreviations are now so it'll be easier then.

[FastCargo 412]

Intercept ELP...is that under an Engine Out boldface?

 

If so, it may stand for something like Emergency Landing Pattern...basically a high, fast spiral glide to a dead stick landing.

 

PCL - Power Control Lever - a fancy way of saying throttle...I'd assume it manipulates the prop RPM, prop pitch, throttle position, etc to give the pilot a 'one throttle' setup.

PMU - Power Management Unit - A box that controls the engine...basically a digital interface that takes the inputs from the PCL, evals several factors (altitude, airspeed, temp) and adjusts the engine accordingly.

 

At least, that's what I think those things mean...

 

FC

[Viggen 644]

Intercept ELP...is that under an Engine Out boldface?

 

If so, it may stand for something like Emergency Landing Pattern...basically a high, fast spiral glide to a dead stick landing.

 

 

FC

 

 

Yeah, Engine Failure During Flight.

Zoom/Glide - 125 knots minimum, PLC off, Intercept ELP.

 

I guess that can bring up what the PLC is again. For most of the boldface, the PLC is off.

 

 

I know you're a fast jet guy so this isn't your area of expertise, but I appreciate the help.

Edited May 12, 2009 by JA 37 Viggen

[CoopF4 0]

The last time I flew a T-6 was in March of 2008 so I might be a bit rusty, but from my Phase II days of UPT here's what I can tell you.

 

PCL is indeed the Power Control Lever - it's a way of combining the power and propeller levers from a traditional prop driven airplane into one. It automatically selects the apporpriate blade angle on your propeller, thus giving you optimum efficiency based on what type of power level (i.e. where you place the PCL) you are asking from the engine.

 

An ELP is known as an Emergency Landing Pattern, and it's basically a dead stick landing, but the point of the ELP is to try and position yourself at an optimum position (actually there are several positions and they are known as "keys" - namely high key, low key, and base key) to make a safe landing with no power. You learn how to manage your energy by using things such as the gear and flaps as well as wing displacement from the runway. We practiced ELP's quite a bit in the T-6 as a matter of fact. On windy days, they are quite challenging.

 

PMU is the power management unit. It's yet another of the many automated little whiz-bang gadgets in the T-6 that just assists the pilot in flying the airplane safely and remaining within the limits of the engine (i.e. preventing over-torque, excessive ITT, etc.)

 

Maximum ITT the maximum Interstage Turbine Temperature. That is the maximum limit in terms of degrees celsius that the engine can go to before damage occurs and depending on the regime of flight (start-up, cruise, etc.) these limits vary. There are also certain time restrictions. From what I can remember the T-6 had a maximum ITT limit of about 1000 degrees Celsius on startup, but the limit for that was 5 seconds maybe?....something like that I think. Oh, and for informational purposes, the ITT is read from the combustion chamber which is located between the compressors and the power turbines.

 

Np is the speed at which your propeller turns. The reduction gearbox in the front of the engine basically converts the very high speed of the compressors to a manageable speed for the prop to turn. I can't remember the T-6 prop speed, but I believe it was somewhere around 1700 rpm...just a guess though my memory of that is fairly fuzzy.

 

N1 is the speed at which your compressors turn. It's generally around 30,000 rpm I believe, which is why the reduction gearbox is so important. No propeller could ever withstand rotations that fast.

 

Regarding the G-limits. The difference between symmetric and asymmetric is whether or not you are rolling the airplane when you pull back on the stick. For example. If you take the stick and simply pull it directly back into your lap, the maximum positive G-limit for the T-6A is about +7.0. Conversely, if you roll while pulling back on the stick, your limit goes down to about +4.7 (from what I can remember). Asymmetric G-limits are always lower because more stress is put on the airframe and in many different places.

 

My T-6 days were a little bit ago so I'm not 100 percent on the numbers, but the general information I gave you should answer your questions.

 

Anyways, hope it helped you out!

[Viggen 644]

That was exactly what I was looking for! Makes me think as though you had all the data sitting next to you.

 

 

Thanks everyone!

Edited May 12, 2009 by JA 37 Viggen

[CoopF4 0]

I can probably dig through my old T-6 stuff if you are looking for anything else. I'm fairly certain I still have boldface/ops limits sheets and other T-6 related stuff in a folder somewhere in my closet.

 

Glad I could help.

[Viggen 644]

One more question for now.

 

What's an OBOGS?

[Vampyre 24]

One more question for now.

 

What's an OBOGS?

 

OnBoard Oxygen Generating System. It replaced LOX bottles for aviator breathing oxygen.

[Jrz 0]

Maximum ITT the maximum Interstage Turbine Temperature. That is the maximum limit in terms of degrees celsius that the engine can go to before damage occurs and depending on the regime of flight (start-up, cruise, etc.) these limits vary. There are also certain time restrictions. From what I can remember the T-6 had a maximum ITT limit of about 1000 degrees Celsius on startup, but the limit for that was 5 seconds maybe?....something like that I think. Oh, and for informational purposes, the ITT is read from the combustion chamber which is located between the compressors and the power turbines.

 

Np is the speed at which your propeller turns. The reduction gearbox in the front of the engine basically converts the very high speed of the compressors to a manageable speed for the prop to turn. I can't remember the T-6 prop speed, but I believe it was somewhere around 1700 rpm...just a guess though my memory of that is fairly fuzzy.

 

N1 is the speed at which your compressors turn. It's generally around 30,000 rpm I believe, which is why the reduction gearbox is so important. No propeller could ever withstand rotations that fast.

 

Regarding the G-limits. The difference between symmetric and asymmetric is whether or not you are rolling the airplane when you pull back on the stick. For example. If you take the stick and simply pull it directly back into your lap, the maximum positive G-limit for the T-6A is about +7.0. Conversely, if you roll while pulling back on the stick, your limit goes down to about +4.7 (from what I can remember). Asymmetric G-limits are always lower because more stress is put on the airframe and in many different places.

 

My T-6 days were a little bit ago so I'm not 100 percent on the numbers, but the general information I gave you should answer your questions.

 

Anyways, hope it helped you out!

 

Mostly correct indeed, but just for the numbers: you have the correct values for the max itt during start (1000 for 5 sec). The other ITT limits are:

Idle - 750 deg celcius

Steady - 820

Transient - 870

 

N1: 30.000 RPM -> NP: 2000 RPM (15:1 ratio by the reduction gearbox)

 

G limits:

Symmetric clean: -3.5 to 7.0 G

Symmetric gear/flaps: 0 to 2.5 G

Asymmetric clean: -1 to 4.7 G

Asymmetric gear/flaps: 0 to 2 G

 

If there is anything else you need to know, let me know!

[JediMaster 451]

Some planes have OBOGS, others still have LOX bottles. It depends on the plane and the model.

[Viggen 644]

Alright, I'm in school right now, but I'm done with my work and can be on here. Any way, what does this mean?

 

Maximum Icing Band/Icing Type

light rime

PUBS Storage

Glare Shield Storage Bag

[Jrz 0]

Alright, I'm in school right now, but I'm done with my work and can be on here. Any way, what does this mean?

 

Maximum Icing Band/Icing Type

light rime

PUBS Storage

Glare Shield Storage Bag

 

The icing band is the layer of air which has icing in it and the maximum band is a 5000 ft layer of air which you are allowed to transition through on your climb or descent. But this 5000 ft counts only when it's light rime ice. Rime ice forms by direct freezing of small water droplets on your airframe. Light describes the intensity of the build up of ice. Light icing is a slow build up, which can create a problem if you stay in the weather long enough.

 

PUBS storage are a few small storage spacings left and right of your seat to keep your approach plates, charts etc.

 

Glareshield storage bag is a specially designed bag which can be attached to your glareshield.

[+ST0RM 145]

Some planes have OBOGS, others still have LOX bottles. It depends on the plane and the model.

 

We've got GOX on the -135. That OBOGS is a pretty cool system.

[+Jarhead1 27]

Glareshield storage bag is a specially designed bag which can be attached to your glareshield.

 

 

To protect it right?

[Jrz 0]

Glareshield storage bag is a specially designed bag which can be attached to your glareshield.

 

 

 

To protect it right?

 

Nah, you have to see it as a big cover with some extra pockets to put your stuff. (The max weight your glareshield can hold is 8.5 pounds) It comes in handy as a place to put your extra charts etc which don't fit in your pubs storage compartments (because they aren't that big, 2 FLIP's and it's full). I tried to find a picture, but I didn't find anything.

[FastCargo 412]

We've got GOX on the -135. That OBOGS is a pretty cool system.

 

Until you get black lung from the zeolite... .

 

We used to joke about that in the Bone community because we have MSOGS (same thing)...

 

FC