Indian Military Aviation - 21 Sept 2015

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Re: Indian Military Aviation - 21 Sept 2015

Post by vina »

Pah! What a crummy looking plane. Yellow in colour ! Cant HAL even paint their planes ? Bad!
Plane seems so slow . Even WWII planes like Spitfire and BF109 seem faster than that.. HAL is 70 years behind.. Bad ! Bad!
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Re: Indian Military Aviation - 21 Sept 2015

Post by Karan M »

Y. Kanan wrote: People need to stop living in the past. It's 2016 and there hasn't been an air-to-air gun kill since 1965,

1971 Indo-Pak war.
1973 Arab-Israeli war.

Gun kills occurred in both.
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Re: Indian Military Aviation - 21 Sept 2015

Post by hnair »

In this age of numerous slow flying UAVs, gun-kills are going to spike up between opponents with robust UAV fleets. There is no point in wasting an expensive shot on a cheap-ass paki quadcopter lugging a gopro with return-receipt still attached

(This "a-o-a missile for everything" suggestions has its equivalence in Naval threads with the "if it floats, use Brahmos" suggestions. We hear how Saryu and Kamorta class are under-armed, due to "no brahmos sticking out of the stack" et al. 99% of their life is spent on the peace-time beat, swatting the rumps of pirate crafts with a well-oiled cane)
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Re: Indian Military Aviation - 21 Sept 2015

Post by deejay »

HTT 40 flew again. I caught a brief sight. And it had a chase plane (HJT 16) chasing it, again.
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Re: Indian Military Aviation - 21 Sept 2015

Post by JayS »

indranilroy wrote:CONGRATULATIONS HAL!!! I have supported this project from its inception. So, I am super happy. The jingo in me still wanted to see them retract the wheel and perform some acrobatics in the first flight itself, in honour of their inspiration: Dr. Ghatge, Capt. Jimmy Munshi and the HT-2.
IR, did you see the video posted few posts ago of HAL presentation?? It mentions that HAL in 1951, when flew HT-2 for the first time, the pilot performed all kinds of manoeuvres such as climbs, turns, stalls and even spin, in 40 odd min flight..!! Now that needs some balls.
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Re: Indian Military Aviation - 21 Sept 2015

Post by brar_w »

People need to stop living in the past. It's 2016 and there hasn't been an air-to-air gun kill since 1965,

From the link to the study (CSBA) posted a few pages ago:
Between January 1970 and the beginning of the Yom Kippur War in October 1973, the IAF claimed 112 victories. Forty of these were credited to missiles and sixty- ve to guns. The thirteen Arab victory claims were all credited to missiles. The big shift came during the Yom Kippur War when the IAF scored seventy-nine of its 164 claimed victories with missiles and only eighty-three with guns. By the close of the decade, the IAF claimed an additional six- teen kills—eleven credited to missiles and only three to guns....

As illustrated by Figure 11, improvements in ghter sensor and weapon capabilities had a dramatic e ect on the nature of air combat during the 1980s. The rst thing to note is that aerial combat was still quite common during the 1980s. The ongoing con ict between Israel and Syria over Lebanon and the Falkland Islands War are widely known examples. The bulk of claimed victories, however, stem from the long and bitter Iran-Iraq War that raged for most of the decade.34 There are relatively few good sources on the aerial dimension of this con ict, but those that exist indicate that the Islamic Republic of Iran Air Force (IRIAF) succeeded in maintaining a signi cant number of the F-4, F-5, and F-14 ghters it received from the United States during the 1970s in working order. Their crews, all trained in the United States, were credited with over two hundred aerial victories including sixty-two kills by F-14 crews using AIM-54 Phoenix missiles.35 The second noteworthy aspect of 1980s aerial combat is the massive decline in gun use. During the 1970s over two hundred aerial victories were credited to guns, but during the 1980s the total declined to just twenty-six (an 87 percent decline). This was accompanied by a similarly large increase in the proportion of victories credited to all aspect missiles (including the AIM-9L) and true BVR missiles such as the AIM-54 and improved versions of the AIM-7.

While the frequency of aerial combat has declined greatly compared to the 1960s—1980s, the number of aerial victory claims registered since 1990 is su ciently large to permit simple quantitative analysis of the kind presented throughout this chapter. The left-hand panel of Figure 13 reveals a continued shift in the mix of weapons employed in aerial combat during the post–Cold War era. The rst thing to note is the virtual absence of victories credited to guns. The database includes two gun victories; the last was a Venezuelan AT-27 Tucano armed trainer shot down by a Venezuelan F-16 during a coup attempt in November 1992. Taking a longer perspective, the data shows the continued utility of guns in aerial combat through the 1970s and their rapid eclipse by missiles beginning in the 1980s.38 In fact, the use of guns in aerial combat virtually ended after the Yom Kippur War in late 1973. Out of 498 victory claims since that time, 440 (88 percent) have been credited to AAMs and only thirty to guns.39 The last gun kill of one jet combat aircraft by another occurred in May of 1988 when an Iranian F-4E downed an Iraqi Su-22M with 20 mm cannon fire.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Jacob »

deejay wrote:HTT 40 flew again. I caught a brief sight. And it had a chase plane (HJT 16) chasing it, again.
I too saw the twins fly over my apartment. Nice looking birds. GJ HAL
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

deejay wrote:HTT 40 flew again. I caught a brief sight. And it had a chase plane (HJT 16) chasing it, again.
Admins where are the like and retweet buttons?
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

brar_w wrote:
People need to stop living in the past. It's 2016 and there hasn't been an air-to-air gun kill since 1965,

From the link to the study (CSBA) posted a few pages ago:
The last gun kill of one jet combat aircraft by another occurred in May of 1988 when an Iranian F-4E downed an Iraqi Su-22M with 20 mm cannon fire.
Thanks - I was looking for the data you have posted. Do you have a link?
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Re: Indian Military Aviation - 21 Sept 2015

Post by brar_w »

Yup.

Study: http://csbaonline.org/publications/2015 ... periority/

Audio: https://www.youtube.com/watch?v=LmGRn7G ... e=youtu.be

One thing to note, The Gulf war occurred <20 years after the end of the Vietnam Conflict and its been 25 years since the gulf war. Advances made in that 25 years (and beyond) won't really be collectively documented till there is similar data available probably a few decades down the road. There has been a substantial leap in capability when it comes to battle management, sensors, weapons, IFF, data-links, multi-spectral Situational Awareness, Combat aircraft signature reduction, training aids and training in general, ECM, ECCM, etc since the gulf war which was essentially fought with technology designed and largely developed in the 70s and 80s. Essentially, if one were to send them up now to replay the gulf war they won't really approach it in the same way and neither would their opponents. At the time of Gulf War, the main go to weapon (BVR) was the advanced Sparrow and the AMRAAM A had barely become operational (they did record kill/s). Fast forward to today, and you have gone through the B, multiple C upgrades and now have close to 1300 Delta models in service, and are thinking beyond. A decade after the Gulf war, they had already concluded two very successful programs to develop multi-spectral seekers (IR (M/W and L/W) and RF) as they looked beyond the AMRAAM. ECM and ECCM capability has also shown massive increases in capability and the cost and procurement of active BVR weapons has grown exponentially...

This has a substantial impact on how an air-campaign is executed in a near peer situation when both opponents bring 1000's of BVR weapons in to play that have to be countered, defeated, or otherwise dealt with...With the trend heading toward 70-100 km shots (non-cooperative target) with the AIm-120D and meteor (and other similar weapons), and the near term bringing in multi-spectral and cooperative opportunities (weapons to platforms, and even weapons to weapons) you are essentially dealing with air-air medium ranged SAM equivalents given how the footprints for computing and electronics in general has been shrinking.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Kakarat »

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Re: Indian Military Aviation - 21 Sept 2015

Post by BharadwajV »

^^
Nice!
Also thanks to Shri.Parrikar for the share!
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Re: Indian Military Aviation - 21 Sept 2015

Post by suryag »

The fangs are the exhausts ?
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Re: Indian Military Aviation - 21 Sept 2015

Post by Lalmohan »

yes and the 'eyes' are inlets
nice mouth
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Re: Indian Military Aviation - 21 Sept 2015

Post by Kartik »

someone on another forum had mentioned how the positioning of the exhausts downwards, will lead to problems with getting hot exhaust gases directed at the landing gear and the tires..especially when the airplane is on the ground, taxiing or waiting on the apron for prolonged periods. Overheated tires could burst.

I've looked at all other trainers I could think of and their exhaust is directed more in a direction towards the cockpit..basically upwards of the landing gear.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Indranil »

nileshjr wrote:
indranilroy wrote:CONGRATULATIONS HAL!!! I have supported this project from its inception. So, I am super happy. The jingo in me still wanted to see them retract the wheel and perform some acrobatics in the first flight itself, in honour of their inspiration: Dr. Ghatge, Capt. Jimmy Munshi and the HT-2.
IR, did you see the video posted few posts ago of HAL presentation?? It mentions that HAL in 1951, when flew HT-2 for the first time, the pilot performed all kinds of manoeuvres such as climbs, turns, stalls and even spin, in 40 odd min flight..!! Now that needs some balls.
We are speaking of Capt. Munshi here. Both HT-2s real first flight and Capt. Munshi's stint as HAL's chief TP. A worthy read for any Indian aviation aficionado.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Indranil »

Kartik wrote:someone on another forum had mentioned how the positioning of the exhausts downwards, will lead to problems with getting hot exhaust gases directed at the landing gear and the tires..especially when the airplane is on the ground, taxiing or waiting on the apron for prolonged periods. Overheated tires could burst.

I've looked at all other trainers I could think of and their exhaust is directed more in a direction towards the cockpit..basically upwards of the landing gear.
Short Tucano, kestrel 350
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Re: Indian Military Aviation - 21 Sept 2015

Post by Suresh S »

HTT u beauty. Now I did not contribute anything towards this plane yet why do I feel so proud? I watch this 15 second video multiple times. There is something about apna and paraya as a sikh friend in UK used to say.
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

Kartik wrote:someone on another forum had mentioned how the positioning of the exhausts downwards, will lead to problems with getting hot exhaust gases directed at the landing gear and the tires..especially when the airplane is on the ground, taxiing or waiting on the apron for prolonged periods. Overheated tires could burst.

I've looked at all other trainers I could think of and their exhaust is directed more in a direction towards the cockpit..basically upwards of the landing gear.
I note that in the Pilatus PC 7 and PC 9 the main wheels are placed closer to the fuselage and retract outwards and are more likely to be in the path of the exhaust. Hence the exhaust pipes are pointed away from the wheels. The HTT 40 has mainwheels that are situated further away from the fuselage and retract inwards and are much farther away from the exhaust stream close to the fuselage.

Overheated tyres could burst? That is an interesting argument but I just want to point out that the exhaust stream is blown away by the propeller. Even without that it would take fairly close proximity to get the tyre temperatures up to dangerous levels. In India - tarmac temperatures of 50 degrees Centigrade are common. Rubber melts at 180 degrees and unless the exhausts were in very close proximity to the tyres it would be difficult to raise tyre temperatures above 40 degrees on exhaust gases alone. Human body temperatures are around 37 deg C, and 40 degrees would feel warm to touch and 50 degrees C hot but stiil just touchable. 60 degrees is too hot to touch.

Also:
http://code7700.com/g450_landing_gear_tires.html
Tire temperatures can rise in excess of 200°F (93°C) above ambient during operation.
That apart - in the image of the Shorts Tucano linked below - why does nobody worry about melting and overheating of the fuselage skin just inches away from the exhaust pipes? No one ever seemed to a ask these questions until someone saw an image of the HTT40
https://upload.wikimedia.org/wikipedia/ ... o-1449.jpg

The real issue as I see it is doubting the ability of Indian engineers to think of a fairly basic no brainer issue while designing an aircraft - in keeping with a general feeling that our people tend to make silly mistakes.

This "exhaust pointing down" argument reminds me of the first mock up images of the LCH when some wisecrack commented that having an EO ball above the nose would make things below the helo invisible. Yeah right. But the EO ball is meant to see what is in front and below and by placing it above the nose it is better placed to see aerial threats like UAVs above the helo. Another example of thinking that the Indians must be stupid. It was only set right when Hari Nair came on here and said it was fine.
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Re: Indian Military Aviation - 21 Sept 2015

Post by srai »

HTT-40 mock had the exhaust like PC-7II.

Image

But on the prototype it has changed to something like Short Tucano.

Image

Anyone know the advantages of either placement? Or is it related to the type of engines being used?
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

The red one is a mock up. The undercarriage & actuators are solid rods
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Re: Indian Military Aviation - 21 Sept 2015

Post by Indranil »

The placement of the exhaust has nothing to do with the airplane designers, but everything to do with the design of the engine fitted into the plane. When the mockup was shown in AeroIndia11, they had planned to go with a PT6A which has the exhaust on the sides. However, during the course of the final design, they chose the TPE331-12B engine which has its exhaust at the bottom. I leave it to interested members to learn why the TPE331-12 series,14 series etc. have the exhaust at the bottom.

And no, the exhaust warming up the tyres is a non-issue. I have never come across this.
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Re: Indian Military Aviation - 21 Sept 2015

Post by tsarkar »

indranilroy wrote:When the mockup was shown in AeroIndia11, they had planned to go with a PT6A which has the exhaust on the sides. However, during the course of the final design, they chose the TPE331-12B engine which has its exhaust at the bottom.
If memory serves right, the Garrett TPE331 is the same engine as Dornier Do228 built in 100s by HAL, and has proven reliable characteristics in multiple environments across India. Good move that reduces program risk.
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Re: Indian Military Aviation - 21 Sept 2015

Post by GeorgeM »

Exhaust should not be an issue. Typical exhaust temperatures for Diesel engines are around 1350F (~740C) with turbo charging. Assume Turbo consumes some of the energy (~20-30 %). Assume aviation exhaust temperatures similar to diesel. But about a foot away from the exhaust stack, the temperature drastically drops to around 400-500 F (260C). This is due to looses from mixing and radiation.
With landing gear that far away (looks like several feet from pic), temperature from exhaust should not be a problem at all, even for slow speed taxi. At take-off speeds, the mixing is significant.
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

indranilroy wrote:The placement of the exhaust has nothing to do with the airplane designers, but everything to do with the design of the engine fitted into the plane. When the mockup was shown in AeroIndia11, they had planned to go with a PT6A which has the exhaust on the sides. However, during the course of the final design, they chose the TPE331-12B engine which has its exhaust at the bottom. I leave it to interested members to learn why the TPE331-12 series,14 series etc. have the exhaust at the bottom.
It appears that there are a few aircraft in which the engine is mounted upside down, with intake above the prop hub and have the exhaust pointing backwards
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Re: Indian Military Aviation - 21 Sept 2015

Post by Indranil »

Yes, the intake can be above the propeller shaft, but it is not an engine mounted upside down. This is not typically down for a single engine aircrafts as its hampers visibility over the nose.
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Re: Indian Military Aviation - 21 Sept 2015

Post by symontk »

I had seen the HTT landing after first flight itself. It landed from Marathahalli side, chase plane was with it until last moment. And it appeared quite close to HTT. Strange. Maybe HAL was so confident in the first flight itself

Do anyone know where this will be produced? I am asking since I am not sure if HAL Bangalore will have space for ALH, LCH, LCA, AJT, Jagaur and HTT. Also Saras is also in pipeline
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Re: Indian Military Aviation - 21 Sept 2015

Post by Indranil »

Kanpur
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Re: Indian Military Aviation - 21 Sept 2015

Post by symontk »

Thanks sir
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Re: Indian Military Aviation - 21 Sept 2015

Post by Kartik »

indranilroy wrote:The placement of the exhaust has nothing to do with the airplane designers, but everything to do with the design of the engine fitted into the plane. When the mockup was shown in AeroIndia11, they had planned to go with a PT6A which has the exhaust on the sides. However, during the course of the final design, they chose the TPE331-12B engine which has its exhaust at the bottom. I leave it to interested members to learn why the TPE331-12 series,14 series etc. have the exhaust at the bottom.

And no, the exhaust warming up the tyres is a non-issue. I have never come across this.
well, I've come up against an issue with ECS pack causing overheating of panels, which was only noticed during a very late phase of the design. led to a heck of a lot of rework. So, these things can happen. But seeing the Shorts Tucano as per your last post did make it appear that this particular exhaust placement may probably be a non-issue. Which would be good, since any re-design would lead to added time to the schedule.

Shiv saab, tyres can burst due to excessive heat. But maybe the wash from the propeller diffuses the heat, so it may not be an issue at all in service.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Sid »

Did some touchup on pic shared by Mr DM. Wish they share more high res pictures from such events.

https://www.flickr.com/photos/29397841@ ... es-R688F4/
Image
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Re: Indian Military Aviation - 21 Sept 2015

Post by JayS »

shiv wrote:
indranilroy wrote:The placement of the exhaust has nothing to do with the airplane designers, but everything to do with the design of the engine fitted into the plane. When the mockup was shown in AeroIndia11, they had planned to go with a PT6A which has the exhaust on the sides. However, during the course of the final design, they chose the TPE331-12B engine which has its exhaust at the bottom. I leave it to interested members to learn why the TPE331-12 series,14 series etc. have the exhaust at the bottom.
It appears that there are a few aircraft in which the engine is mounted upside down, with intake above the prop hub and have the exhaust pointing backwards
Since the intake is for a centrifugal compressor you can have the opening anywhere on the circle - up, down or sideways. Likewise you can place the engine itself anywhere around the propeller. UP or Down make most sense from aircraft design point of view. So in a way you are right. But this does not affect the exhaust position. This is the cross section of TPE331 engine. You can see what Up or down really would be from this image. Putting link as image is too big. As IR already pointed out, putting air intake above for nose mounted single engine birds would hamper visibility over the nose. While for the multi-engine, wing mounted aircrafts, both up and down configurations are in use.

https://en.wikipedia.org/wiki/Garrett_T ... utaway.jpg

The difference in exhaust position is due to the fact that the PT6A engine is reverse flow i.e. intake at the back and exhaust at the front. See last part of this video which shows the airflow. OTOH the TPE331 engine is usual front intake-back exhaust flow.


Interestingly this one aircraft which used PT6 in pusher configuration looks more natural in terms of placements of intake and exhaust since reverse flow becomes straight flow here due to reverse mounting of the engine itself.
Image
Another interesting difference between the two engines (unrelated to the exhaust position) is the former is two-shaft design and the later is single shaft - which is the reason i think that the later one needs big reduction gear box for the propeller.
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

Among multi engine a/c the BAe Jetstream and OV 10 Bronco have the engine mounted "upside down". The new single engined Garett powered Antononv AN-2 also has an "upside down" Garett TPE 331

https://img.planespotters.net/photo/344 ... 344050.jpg
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Re: Indian Military Aviation - 21 Sept 2015

Post by Aditya G »

Is Garett TPE 331 license produced by HAL?

Smart engine choice by HAL in any case, compared to the Sitara IJT fiasco.
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Re: Indian Military Aviation - 21 Sept 2015

Post by tsarkar »

Aditya G wrote:Is Garett TPE 331 license produced by HAL? Smart engine choice by HAL in any case, compared to the Sitara IJT fiasco.
Yes, very smart to reuse the basic Do228 engine license produced since 1988.

Though the 12B is a newer version with higher power. Presently HAL can service 12 series engine, but I speculate a license manufacture will shortly follow.

http://www.hal-india.com/Product_Detail ... y=&CKey=29
The Garrett TPE 331-5 Turbo prop Engine is being manufactured, overhauled and repaired for various Customers under licence from Garrett Engine Division of Honey Well Company [earlier Allied Signal Aerospace Company, USA] since 1988 and belongs to one of the most popular series of small Turbo prop Engines powering a large number of Commuter and Corporate Aircraft such as Dornier DO-228.

It has a single shaft Centrifugal Compressor Engine rated at 715 shaft horse power at 1591 RPM output speed. Being a reverse flow Gas Turbine with a small frontal area, it has better dry specifics and easier airframe integration. Apart from its simplicity of design and superior performance, the engine features a propeller control system, anti-icing and foreign object damage resistance, reverse thrust and negative torque sensing facilities. The division is also an authorised service centre for Garrett TPE 331-5 series engines up to - 12.

Main Characteristics
Maximum Diameter (m): 0.7
Length (m): 1.11
Weight (kg): 164
Power: 715
Specific Fuel Consumption(kg / shp-hr): 0.268
Last edited by tsarkar on 05 Jun 2016 14:46, edited 2 times in total.
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Re: Indian Military Aviation - 21 Sept 2015

Post by tsarkar »

Here's my contribution to the exhaust up/down/port/starboard and engine up/down/port/starboard discussion.

The TFTA MQ-9 Reaper that uses the same Garrett 331 engine in a pusher configuration

https://upload.wikimedia.org/wikipedia/ ... 1M-959.jpg
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

I have a question about the HTT 40s exhaust pipes and this is a thermodynamics type of question for which I have no answer - only guesswork. The issue is minor.

If you look at the enlarged area of the HTT 40 image below you find that the exhaust pipes are cut "obliquely" and not orthogonally to the axis of the pipe. Many other aircraft including the image of the An-2 I have linked above have the exhaust pipe cut orthogonally. The oblique cut appears to be a design choice rather than a cosmetic variant.

From the rudimentary school level thermodynamics I can recall there are some design advantages in cutting the pipe obliquely in some situations. In this case the area of the outlet is larger and would lead to early cooling of gases and mixing with ambient air, apart from redirecting the exhaust flow away from the axis of the pipe - just like those AK-47s whose muzzle is cut obliquely to create an up-blast to counter the bucking up tendency of the AK-47 whose barrel is located above the center of mass.

Also - the engine is after all a jet engine and the mass of air flowing out is what would be expected from a jet engine and must be producing some degree of thrust - however minor. I wonder how much the exhaust outlet configuration is designed to utilize (or minimize) that thrust?
Image
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Re: Indian Military Aviation - 21 Sept 2015

Post by Y. Kanan »

shiv wrote:
Y. Kanan wrote: People need to stop living in the past. It's 2016 and there hasn't been an air-to-air gun kill since 1965,
Bullshit will be called out:
http://www.bharat-rakshak.com/IAF/Database/10877
http://www.bharat-rakshak.com/IAF/histo ... asand.html
If you have to reach all the way back to 1972 to make your point, you have failed.

Guns are irrelevant in ATA combat and have been for decades. This is the reality and a few counter-examples from a distant bygone era don't change that.

This is a ridiculous argument; I can't believe we're even having it.
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Re: Indian Military Aviation - 21 Sept 2015

Post by Singha »

guns have however been used by even F-15s in afpak ... for strafing runs once they ran out of bombs

even the eurofighter, JSF, F22 has a gun, despite attempts to delete it.
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Re: Indian Military Aviation - 21 Sept 2015

Post by shiv »

Y. Kanan wrote: This is a ridiculous argument; I can't believe we're even having it.
You are the one who opted to join it with the wrong date, insisting that 1965 saw the last gun battle which is itself ridiculous.

There is no need for the "we" if you withdrew yourself and did not worry about what others talk about. You can ignore what is being discussed and forestall what seems to be your sense of profound disbelief and possible great distress being caused to yourself that "we" are having this discussion. It is YOUR choice to join or leave. "We" need not be discussing this stressful issue. What others talk about will not distress you when you opt out no? Your call.
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