|
|
Kfir mishap averted
Full News Article
boola
Joined: Apr 2006
Posts: 90
Member Profile
|
 23 Sep 2006 12:33:07 GMT Report for Abuse
|
Hi Mig-29C,
Thanks. Looking forward for some new info from you. Bye. |
Sandman
Senior Member
Joined: Mar 2005
Posts: 1720
Member Profile
|
 23 Sep 2006 22:52:08 GMT Report for Abuse
|
Hi Mig29C
How does a helicopter achieve lower noise levels at close to ground flying/hovering ?
I could never understand that in relation to the reduced air cusion under the rotors at lower altitude which should technically require a higher frequency of revolutions to stay airborne and hence cause greater noise.
Thanks for your great insights and the pics on web. |
Sandman
Senior Member
Joined: Mar 2005
Posts: 1720
Member Profile
|
23 Sep 2006 22:57:57 GMT Report for Abuse
|
Mig 29C
Another question.
Why hasn't the SLA invested in the hand carry-able small scale UAV's that are proving to be a cheap and effective weapon for special forces ops in other places ? Almost everyone seems to be making them, including the hizbullah types. Wouldn't it be cheaper to invest in a whole fleet of them, and be able to monitor a larger area simultraneously and with less risk at loss of any ? |
Mig-29C
Joined: Jun 2005
Posts: 543
Member Profile
|
 25 Sep 2006 10:33:11 GMT Report for Abuse
|
Dear Mr.SenaM
You say the R-550 air-to-air missile to be carried in Mi-35P h'copters will be use-ful/effective in 'taking-out' the threat from LTTE aircraft. But currently what they have are only piston-engined a'cft (probably nos. 2) - with a feeble IR signature. So, do you expect the R-550 (an IR guided missile) to be effective against these a'cft ?
It seems to me the Mi-35P - after missing with the missile - will have to close-up, and blast the LTTE craft out of the sky with cannon-fire.
In reply to your question ..
The R-550 missile series opted by the SLAF are R-550 MkII variants and not the older MkI. The MkII has an all-aspect IR seeker (AD3633) compared to the rear engagement seeker on the MkI (AD3601).
The Mk1 has a mechanically scanned single colour optical seeker which works In the 3-5 micron wavelength range which limits it to rear aspect engagements, primarily jet engine exhausts. The exhaust emissions of a Zlin 143 engine (TEXTRON LYCOMING J3A5 piston engine - the exhaust manifolds are on the underbelly of the aircraft ), which will contain sufficient concentrations of carbon dioxide whose wavelength falls smack back in the 3-5 micon wavelength range can theoretically be tracked by this type of seeker. However this would be the only target source for this type of seeker.
The seeker on the MkII is an all-aspect two colour seeker operating in the 3-5 and 8-13 micron wavelength range, which incidentally is absorbed the least by the atmosphere hence providing a continuous target source. The MkII seeker also utilises an imaging infrared (IIR) capability, where the IR/UV sensor - a focal plane array - is able to ''see'' in infra-red, much like the CCD in a digital camera. This allows the seeker to discriminate between the surrounding atmosphere and the radiation emitted by the aircraft skin while In flight.
As a result this allows the R-550 MkII seeker to target 3 areas: visual IR/aircraft radiation and the engine exhaust plume. The Zlin 143 will be actively emitting in all three target areas, with a cruise speed of 235km/h, the radiation emitted by this aircraft is sufficient for this class of seeker to track successfully coupled with its engine emissions.
The R-550 has the additional ability to be launched at very low speeds making this missile ideally suited for this role.
Incidentally the SLAF already has in stock Chinese PL-3 and PL-5 IR guided missiles. These missiles were part of the K-8 package it received in 2000. However both missiles have a single color IR seeker and hence restricted to rear hemisphere engagements, with the engine exhaust as the only target source. They also have launch speed restrictions thus not being suitable for carriage on Mi-35s. The R-550 MkII is the best option available for the SLAF Mi-24 fleet looking for an air/air capability to shoot down LTTE Zlin 143 aircraft.
Hope this helps.
Edited By - Mig-29C - 25 Sep 2006 14:22:39 GMT |
Mig-29C
Joined: Jun 2005
Posts: 543
Member Profile
|
25 Sep 2006 10:36:11 GMT Report for Abuse
|
Dear Mr.Sandman
How does a helicopter achieve lower noise levels at close to ground flying/hovering ?
I could never understand that in relation to the reduced air cusion under the rotors at lower altitude which should technically require a higher frequency of revolutions to stay airborne and hence cause greater noise.
With regards to your question: Most helicopters hover within ''ground effect''. This is defined as a height above ground equivalent to the rotor diameter, that is, if the span of the tip of one rotor to the other is 100 feet, then the helicopter is capable of hovering in ground effect up to 100 feet.
The importance of ground effect is that up to that limit, the air is physically compressed beneath the helicopter between the helicopter and the ground, and a cushion of the air is created.
This cushion offers a tremendous amount of lift for the helicopter. In general when a helicopter is within about one-half its rotor span above the ground it is generally considered to be hovering in ground effect. At this low altitude, the helicopter experiences an increase in performance. The ground reduces the vortices coming off the rotor blade tips, reducing induced drag. At the same time, air sucked into the rotor disk from above accelerates downward and hits the ground. Because the ground prevents the air from getting out of the way quickly, the air can't accelerate as rapidly as it does when the helicopter hovers at a higher altitude. This slower induced flow doesn't reduce the angle of attack of the rotor blades as much as it does in a hover at higher altitude, and the rotor can provide more lift at a given power (collective) setting.
At altitudes above ground in excess of one rotor diameter the ground effect is lost, with the result that much more power must be provided by the rotors and more fuel burned as the cushion dissipates, forcing the helicopter to hover by brute force. This also means there is an altitude limit to hovering, even with ground effect.
The highest helicopter hovering capability, under the most unusual circumstances, has been at altitudes of approximately 15,000 to 18,000 feet. Translational flight, or normal forward flight without hovering, is limited to about 30,000 feet, but rarely do helicopters operate at such altitudes.
In addition, during hover flight, at low altitude, a visual obscuration may occur when flying over ground material that can be blown up into the rotors. This causes a ''white out'' with snow, or a ''brown out'' with dust and sand. The result is that the helicopter is engulfed in the cloud of a suspended particulate material and the pilot will lose outside reference and horizon cues.
Why hasn't the SLA invested in the hand carry-able small scale UAV's that are proving to be a cheap and effective weapon for special forces ops in other places ? Almost everyone seems to be making them, including the hizbullah types. Wouldn't it be cheaper to invest in a whole fleet of them, and be able to monitor a larger area simultraneously and with less risk at loss of any ?
Im sure the SLAF is looking into this area :o) .. But your right, such a system would be advantageous in your countries terrain.
Hope this helps
Edited By - Mig-29C - 25 Sep 2006 10:37:34 GMT |
Mig-29C
Joined: Jun 2005
Posts: 543
Member Profile
|
25 Sep 2006 12:31:59 GMT Report for Abuse
|
I see the SLAFs beech reconnaissance assets were in operation again :o)
It can now be clearly seen from recent encounters that these aircraft are providing a key strategic advantage to the SLAF and hence tipping the battle in favour of the Government in almost all encounters.
In addition, the greater time taken by the LTTE in putting out its version of almost all naval clashes of recent memory indicate that the Sea Tigers probably did not do as well as they had expected. |
nirupam
Senior Member
Joined: Aug 2005
Posts: 3527
Member Profile
|
25 Sep 2006 13:09:23 GMT Report for Abuse
|
Killing of Tamil citizens and destruction their houses and livelihood by Kfir bombardment is termed 'special mission' by terrorist state and racist press.
Four Israeli built Kfir jets were to leave on a special mission in the North yesterday
God's wake up call to stop this madness of bombing one's own territory and people.
A grave accident risking the lives of two airmen was narrowly averted when a Sri Lanka Air Force Kfir jet bounced out of the runway while taking off at Katunayake due to engine failure yesterday morning
Two other countries Pakistan and Ethiopia did the same and lost their provinces of East Pakistan and Eritria respectively. East Pakistan and Eritia seceded and became independent contries.
Edited By - nirupam - 25 Sep 2006 13:16:49 GMT |
SenaM
Senior Member
Joined: Aug 2006
Posts: 1908
Member Profile
|
25 Sep 2006 14:07:46 GMT Report for Abuse
|
Mig-29C
Thank you for up-dating my knowledge on the subject. I was going on the impression, IR seekers in these A-A missiles were dependent on a 'strong' heat-source, like a jet engine exhaust.
The R-550 miisile .. is it of French or Chinese manufacture ? (If Chinese, then probably derived from a Russian missile).
Edited By - SenaM - 25 Sep 2006 14:10:11 GMT |
Mig-29C
Joined: Jun 2005
Posts: 543
Member Profile
|
25 Sep 2006 14:20:41 GMT Report for Abuse
|
Mr SenaM
The missile is a French design.
The PAF has both R-550 MkI and MkII variants. |
CannonFodder
Joined: Mar 2005
Posts: 106
Member Profile
|
25 Sep 2006 18:23:01 GMT Report for Abuse
|
Mig29-C;
Thank You for valuble contributions. Among many rants and lies this is the only thread that has something worthwhile. You should be attracting more traffic to this site single handedly than most of us taken together. |
|
Search All News and Discussions