t700-ge-701c 701 or 701C engine?

[FalcoGer]

Which engines do we get?

[Raptor9]

Should be the 701C. There was still a good mix of 701 and 701C engines in the fleet during the 2005-2010 time frame, but the preponderance of engines in line units at the time were 701C.

There was a variety of reasons for why some units, including AH-64A's got the 701C before others, such as those units on the schedule to deploy, especially those going to Afghanistan.

[stormrider]

https://www.geaviation.com/sites/default/files/datasheet-T700-401C-701C.pdf

[Glimmer]

https://www.digitalcombatsimulator.com/en/newsletters/newsletter04062021-lznmu4qxoh6mbd9p5wf3xbs1wg4tb9mz.html

Quote

The flight model is progressing nicely, and we are now developing the flight augmentation systems that include SCAS and HOLD modes. Modeling of the T700 GE 701D EDECU engine and related systems is underway.

Looks like it will be late version with 701D engines, which also are installed on AH-64E.

In this video pilot describes their company / regiment AH-64D and said 701D installed there (from 04:50):

 

Edited October 15, 2021 by Glimmer

[Raptor9]

On 10/15/2021 at 1:49 PM, Glimmer said:

Looks like it will be late version with 701D engines, which also are installed on AH-64E.

In this video pilot describes their company / regiment AH-64D and said 701D installed there (from 04:50):

That newsletter tidbit must be unknowingly based on info out of context. The T701D wasn't even fielded to the Army during the time period.

That video is a more recent video showing a modern day AH-64D, which all have T701D engines now, however the AH-64D being modeled in DCS (2005-2010 according to the announcements) was from a time when they were mostly T701C with some T700 remaining.

Edited October 19, 2021 by Raptor9

[Glimmer]

59 minutes ago, Raptor9 said:

That newsletter tidbit must be unknowingly based on info out of context. The T701D wasn't even fielded to the Army during the time period, and the T701D engines that are installed on AH-64Ds today are not equipped with EDECU's. Only AH-64E T701D engines are equipped with EDECU's.

That video is a more recent video showing a modern day AH-64D, which all have T701D engines now, however the AH-64D being modeled in DCS (2005-2010 according to the announcements) was from a time when they were mostly T701C with some T700 remaining.

 

At least It was written officially, will see closer to release / on release.  

Edited October 15, 2021 by Glimmer

[AlphaOneSix]

The module description on the DCS website says 701C.

[Glimmer]

5 hours ago, AlphaOneSix said:

The module description on the DCS website says 701C.

hmmm, indeed, looks strange, but in this case 701C seems to be more logical choice.

[Raptor9]

For some history on the topic (all unclassified/open source)...

The General Electric T700-GE-700 engine was the original model that was made for the US Army UH-60A and AH-64A aircraft when they were being fielded to the Army in the late 70s/early 80's respectively.  Shortly thereafter, the T700-GE-701 model was fielded to the AH-64A fleet with more shaft horsepower.  When the "Delta" upgrades were being conceptualized in the 90's, the more powerful T700-GE-701C was designated to power the FCR-equipped AH-64D specifically, while non-FCR AH-64C retained the 701 model.

However, as it was discussed previously in this thread (and well known by anyone that is obsessed with the Apache helicopter probably knows) the AH-64C designation was dropped since any AH-64C could have been "made a D-model" by removing the FCR mast-mounted assembly and associated boxes and installing them in another aircraft.  Paperwork is involved, administratively tracking an aircraft as one MDS (Mission/Design/Series) and then another, it would've been a mess.  So all AH-64C's are now AH-64D's, and all AH-64D's would eventually get the T701C upgrades.  By the mid 2000's, some AH-64A units began receiving the T701C engine upgrades as well.  I don't remember what the decisions behind that was, but it was probably for eventual fleet commonality to ease logistical requirements on the supply system.  Or maybe it was to allow AH-64A's to have the additional power available for the altitudes of Afghanistan.

It is worth noting, that at some point, the additional shaft horsepower from a turboshaft engine may exceed the transmission loading limits of a helicopter.  When this happens, any additional power that is available from the engine is "wasted" because the limiting factor is the powertrain system (powertrain being the entire system of transmission, gearboxes, and shaft segments between the engines and rotor systems).  However, this power is only "wasted" at sea level.  If that helicopter is operated in an environment of high DA (Density Altitudes; resulting from high temperatures, high altitudes, or a combination of the two), the engines will operate at higher temperatures.  If the temperatures reach a certain point that the engines have reached an operating limit, and this limit is less than the powertrain is able to handle, then the engine becomes the limiting factor instead of the transmission.  One of the advantages of each successive T700 variant has been the ability to operate at increasingly higher turbine temperatures.  This means they have the ability to produce more power at higher density altitudes.  The high DA effects on helicopters can be experienced in the existing DCS helos if a player wishes to experiment.

As a side note, the UK's Apache AH1 is powered by a different turboshaft engine manufactured by Rolls Royce.  I have no first-hand knowledge of these engines, but from what I am able to gather from open-source performance specs, these engines have more shaft horsepower than even the current GE 701D.  However, as far as I know (I could be wrong) the Apache AH1 has the same powertrain as the AH-64D, which means the additional power these engines provide has no real performance advantage over the General Electric T700-series at sea level.  However, when you get into the higher density altitudes, these engines do provide a power advantage.  It is well known the UK Apache force in Afghanistan still mounted the FCR, whereas the American AH-64Ds did not to provide an increased power margin.  This is also why even the lighter AH-64A's received a power advantage when equipped with the 701C's (over 701's) in Afghanistan, because of the very high density altitudes in the mountainous regions of Afghanistan during the summer.

Then the T700-GE-701D engine, with even greater shaft horsepower, became available around the time the AH-64D Block 3 (which was re-designated the AH-64E in 2012) was nearing fielding; the UH-60 fleet is also fielded with the 701D.  These engines could operate at higher turbine temperatures than the 701C, and when equipped with an Enhanced Digital Electronic Control Unit (among other things), the 701D was even more powerful still.  This is the distinction between the 701Ds installed on AH-64Ds versus those installed on AH-64Es.  Both of the core engines are T700-GE-701D engines, however the 701Ds on the AH-64Es have more advanced engine "accessories" mounted on them allowing the AH-64E to squeeze out additional power into its more robust powertrain system.  So the 701D provides a power increase to both AH-64D and AH-64E, but the AH-64D really only sees the performance increase in high DA environmental conditions.

[BIGNEWY]

Our AH-64D will have T700-GE-701C engines. The mention of the D engines is an error. 

Thank you

The Eagle Dynamics Team

[kgillers3]

Dude… you realize it’s an older version. Lmfao it’s the c engine. It literally says what’s being released with c engines on the module page.  Maybe the confusion is you not reading or understanding the d model existed before our time flying? 

Edited October 19, 2021 by kgillers3

[Raptor9]

On 10/18/2021 at 11:39 PM, Dunkdd said:

I don't understand the confusion on this. I have only ever seen Ds with 701D. Otherwise I would be really confused on the ch. 5 limits. It is hard enough knowing D versus E limits, I am not familiar with anyone going around asking for block 2 or 1 limits. I could be mistaken I was always bad with numbers. 

See source, (unclass)

1) If you had read my explanation (literally 2 posts above yours) of when T700 variants were in service, and the distinction between a 701D mounted in an AH-64D vs those in an AH-64E, you would have seen that there is more to the whole story.

2) In your post, you imply that you are an AH-64 pilot from your apparent need to know Chapter 5 limitations.  You should also know that the manual number you posted a picture from is of the AH-64D Block 3, which is the AH-64E because it was re-designated to the Echo model in 2012.  This probably added to your confusion.  Further, as it has been stated multiple times, ED is making an AH-64D Block 2 from 2005-2010, which is clearly not covered by the document you posted, and certainly was not equipped with 701D engines.

3) In case you aren't aware, just because a document is "Unclassified", that does not mean it is "Approved for public release", nor does it mean you can post pictures from it, or distribute it in any other form.  There is an entire paragraph on the front cover of these manuals that state this.  I would give that a read before considering posting something like that again.  (It's also against forum rules, but I'm not a moderator)