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Author Topic: Sukhoi Su-25 Projects  (Read 9784 times)

Offline PaulMM (Overscan)

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Sukhoi Su-25 Projects
« on: March 03, 2006, 05:11:02 pm »
In the 1976-1979 period, while working on the basic Su-25 design, Sukhoi also did the following preliminary designs:
Su-25K carrier based ship attack aircraft
Su-25UB combat trainer
Su-25T antitank aircraft (Shkval optical system)
Su-25V all weather attack aircraft (Bars nav/attack suite)

Source:
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Offline PaulMM (Overscan)

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Re: Sukhoi Su-25 Projects
« Reply #1 on: April 28, 2007, 03:57:39 am »
Oleg Samolovich recalls in "Next To Sukhoi" being tasked in 1969 with designing a scaled down Su-17 as an alternative to the Su-25 concept (under pressure for supersonic performance)

Quote
В 1969 году Е. А. Иванов предпринял еще одну попытку отстранить меня от проектирования новых самолетов и поручил А. М. Полякову разработать альтернативный проект. Этот проект представлял собой уменьшенную копию самолета Су-17М с крылом изменяемой геометрии. Конечно, пришлось понервничать, но П.
« Last Edit: April 28, 2007, 04:04:24 am by overscan »
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Offline mrdetonator

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Re: Sukhoi Su-25 Projects
« Reply #2 on: April 28, 2007, 06:41:48 am »
Oleg Samolovich recalls in "Next To Sukhoi" being tasked in 1969 with designing a scaled down Su-17 as an alternative to the Su-25 concept (under pressure for supersonic performance)

Quote
В 1969 году Е. А. Иванов предпринял еще одну попытку отстранить меня от проектирования новых самолетов и поручил А. М. Полякову разработать альтернативный проект. Этот проект представлял собой уменьшенную копию самолета Су-17М с крылом изменяемой геометрии. Конечно, пришлось понервничать, но П.

The exact translation is following.

In the year 1969, E.A. Ivanov tried once again to stop me from designing new aircrafts and commanded A.M.Poliakov to elaborate an alternative project. This project represented a scaled down copy of the Su-17M with variable sweep wing. Of course a hassle came, but  P.O.Sukhoi did not accept that project.

where is written the part about "under pressure for supersonic performance"?

Offline PaulMM (Overscan)

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Re: Sukhoi Su-25 Projects
« Reply #3 on: April 28, 2007, 09:04:28 am »
Its my interpretation from the rest of the text, which is full of references to the tension over speed within Sukhoi & between Sukhoi & the VVS. Ivanov wasn't fully behind the subsonic design. You are correct to say it isn't within the quote however.

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Offline mrdetonator

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Re: Sukhoi Su-25 Projects
« Reply #4 on: April 28, 2007, 11:32:33 am »
Its my interpretation from the rest of the text, which is full of references to the tension over speed within Sukhoi & between Sukhoi & the VVS. Ivanov wasn't fully behind the subsonic design. You are correct to say it isn't within the quote however.
Maybe I missed the point but why they(VVS) insisted on the 1200km/h speed? At altitude 1000m (mentioned in the VVS requirements) it is even hardly Mach1!!. So, what supersonic performance were they talking about? Is there any reason why the necessity 1200km/h mentioned there?

correction>. there is written 1200km/h speed near ground, so I think it is ment to be an altitude up to 1000m 
« Last Edit: April 28, 2007, 11:41:47 am by mrdetonator »

Offline PaulMM (Overscan)

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Re: Sukhoi Su-25 Projects
« Reply #5 on: April 28, 2007, 12:22:04 pm »
According to Bedretdinov, in August 1971 the VVS demanded that speed be 1200km/h carrying 4 external B-8 rocket pods, which actually caused Sukhoi to suspend work on T-8 for while (and looked at Su-15 & Su-17 derivatives). Sukhoi thought 900km/h was adequate for the mission. 1200km/h is just about Mach 1. The VVS were somewhat obsessed with the Jaguar, which gave high subsonic speed at low level and Mach 1.6 at altitude.

Mikoyan's MiG-21LSh project fully met the VVS requirements, which the VVS used to try and leverage Sukhoi, but in the end a compromise was agreed on 1000km/h.
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Offline mrdetonator

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Re: Sukhoi Su-25 Projects
« Reply #6 on: April 28, 2007, 01:36:18 pm »
Interesting, just browsed through the Ildar Bedretdinov book and found that A.M.Poliakov was tasked to design an aircraft on the basis of the Su-15(Su-15Sh) whereas Oleg Samojlovich is claiming a scaled down copy of Su-17M. ;)

Anyway, I like the transcription of the discussion(russian orig.) between P.O. Sukhoi and V.R.Efremov, because P.O. is giving him good reasons and explanations for his irrational beliefs regarding the neccessity of supersonic "shturmovik". Well, sometimes high military officials are obsessed with such things.


V.R: Pavel Osipovich, the "Shturmovik" project you offer is very interesting, but the max. speed of 900km/h is not satisfying for us.
P.O: Would you like to have a supersonic "Shturmovik"?
V.R: Yes, of course, take for instance the anglo-french "Jaguar". It will be flying "subsonic" near ground with combat weapon load , but at altitude it can also fly at speeds equaling Mach 1,6.
P.O: hmm, but the "Jaguar" is not "shturmovik", Viktor Romanovich, high altitudes are not typical for Shturmoviks.
.....
.....
P.O: Then for what reason "Shturmoviks" need supersonic, Viktor Romanovich?
V.R: Well, at least for that to flee away from the enemy fighters.
P.O: I think you also do not believe that at Mach1,6 you can bug out before the Phantom.
....
.... ;D ;D


« Last Edit: April 28, 2007, 02:29:40 pm by mrdetonator »

Offline PaulMM (Overscan)

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Re: Sukhoi Su-25 Projects
« Reply #7 on: April 28, 2007, 03:03:21 pm »
Both projects were designed, there's no conflict between sources here.
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Offline mrdetonator

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Re: Sukhoi Su-25 Projects
« Reply #8 on: April 29, 2007, 12:56:13 am »
The following diagram shows limiting/allowable speeds(Mach numbers) and altitudes for attached stores 4xFAB250(8xFAB100), 2xR-60. The allowable max. speed of flight is limited by the strenght of the fuselage, wing mechanization and weapon pylons.   

Diagram explanatory: VPK=LTC - Landing/Takeoff Config, LK=FC - Flight Config, MK=MC - Maneuver Configuration
The max. allowable Mach number for stores with four FAB250(8xFAB100) and two R-60 is 0,82Mach(FC) and 0.71Mach(MC). The max. altitude level (7000m) is given by the ability of the pilot to work in the unpressurized cabin.

For some other stores configuration, as for instance 32xFAB100, 2xR-60 or 4xFAB250, 2xR-60, 2xPTB-800 or 2xR-60, 4xPTB800 the max.allowable Mach number is 0.6 for both the FC/MC regimes.

source: Su-25K practical aerodynamics
« Last Edit: April 29, 2007, 12:59:04 am by mrdetonator »

Offline elmayerle

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Re: Sukhoi Su-25 Projects
« Reply #9 on: April 29, 2007, 04:01:38 pm »
Wasn't there also a three-seat courier version studied of the Su-25UT/Su-28?

Offline Iranian F-14A

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Re: Sukhoi Su-25 Projects
« Reply #10 on: April 30, 2007, 07:20:55 am »
I believe the 3 sea model was known as the Su-25UB-3.The Idea,IIRC was to cut the cost of training by having two students train at the same time,on the same aircraft,with one instructor.

Offline fightingirish

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Re: Sukhoi Su-25 Projects
« Reply #11 on: April 30, 2007, 07:34:17 am »
Ken aka Flanker_man @ Key Publishing Ltd Aviation Forums might still have the scan of the Su-25UZ/Su-25UB-3.

See here: http://forum.keypublishing.co.uk/showthread.php?t=61522&highlight=Su-25
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Offline mrdetonator

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Re: Sukhoi Su-25 Projects
« Reply #12 on: May 01, 2007, 07:47:19 am »
Again a project from the desperate times(early90`s) of the design bureau Sukhoi. I`m really not surprised why most of Mr.Babak "pocket" proposals never got further than outline design stage. This is another crazy idea coming out of his head to build a jet trainer on the basis of the Su-25UB to teach VVS pilots to take-off and land. This project named the Su-25UZ "Ruskaya Troika" was not designed for carrier based operations.
The baseline Su-25 itself has been known for its tricky behaviour during take-off and landing phase. The problem lies with the short spacing between main wheels causing lateral instabilities and oscilations when applying improper pedal inputs during acceleration/decceleration on the runway. When the Frogfoot touches the ground with all three wheels, pilots are instructed to release the brake chute at first and not to compensate the course and maintain runway alignment with pedals what could lead to the swinging motion of the aircraft. Things are going to become even more difficult when compensating for cross-wind. The aircraft is also very sensitive to cross-wind due to its big "boxy" side area, afaik landings with cross-wind up to 10m/s are considered safe, whereas the Mig-21 round fuselage can handle cross-wind up to 20m/s without a problem . The Su-25 has very unusual pedal steering/braking mechanism, not common on other soviet aircrafts.
Making a jet trainer for the flight schools from the Su-25 is a pure madness, that is my opinion.
I bet that two L-39 Albatross jet trainers are still cheaper and better solution for the basic flight training than the 3-seat Frogfoot having even that disgraceful nickname "Russian threesome". ;D ;D

regards
detonator

picture is from Ildar Bedretdinov book, Su-25 and its derivates

Offline Matej

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Re: Sukhoi Su-25 Projects
« Reply #13 on: December 07, 2009, 09:44:49 am »
Next to the collection. During the drawing I was wondering, if the plane is named 25UZ or 25U3 (because of the similarity in azbuka) and it seems, that it really was 25U3.

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Offline Grey Havoc

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Re: Sukhoi Su-25 Projects
« Reply #14 on: April 28, 2016, 03:09:15 am »
Here Comes the New Su-25: Russia's 'Flying Tank' Set for a Lethal Upgrade (The National Interest blog)

Some info on the Su-25SM3 upgrade.
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