[Sutripta]

^^^
My original post was not referring to the Sarus/ Indian certification, but to FAA statement to Embraer.

Regards
Sutripta

[SmartCat]

HAL will start producing Dornier 228s for civilian use (short haul regional airlines)
https://economictimes.indiatimes.com...w/63541929.cms

This plane was till now made for defence forces and was recently certified for civil use, given the 19-seater's suitability for operating short routes under Modi government's ambitious regional connectivity UDAN scheme.

"The list price of this aircraft is Rs 50-55 crore. On a daily basis we are getting queries from small RCS operators. We are in final stages of discussion with them and expect firm orders soon.

[vivtho]

Originally Posted by smartcat

(...) But NAL Saras has propeller behind the engine. (...)

Any idea why this is so? Does mounting propeller behind the engine have any particular cost advantages?

Virtually every element of an aircraft's (or a car's) design is a compromise between various factors like efficiency, performance, ease of maintenance and even looks.

Rear mounted propellers are not uncommon, they were most famously used on the Beechcraft Starship and the Piaggio P.180 Avanti. They offer the following advantages

• A 'cleaner' wing. The more things you have mounted on the wing, the lower its efficiency at its primary job of generating lift. There are exceptions to this rule, but in general, wings without engine or their associated structures are more efficient, allowing a smaller and lighter wing to do the same job as a bigger one.
• Allow for shorter landing gear since they are usually mounted higher than a wing-mounted engine (Of course this does not apply for an aircraft with a high-mounted wing)
• Better engine-out performance. Since the engines are so much closer to each other, in case one engine fails, the aircraft does not yaw 'into' the affected engine as much.

There are some potential disadvantages too

• The engines are somewhat harder to service since they are mounted higher than wing mounted engines which can usually be accessed from ground level.
• Engine noise is greater. On a turboprop, most of the perceived engine noise is actually from the tips of the propellers. A rear-engine installation like this has the propellers much closer to the passenger area leading to more noise.
• Potential for deep stalls. This is not as much of an issue for a smaller aircraft like the Saras, but on larger aircraft, at a high angle of attack, the wing can block airflow to the tail reducing control effectiveness.

Originally Posted by alpha1

In addition to the points made by various people before me, I also have a gut feel that the prop pusher engine mounted at aft will not provide the "straight line stability" provided by a fore mounted engine. Essentially your rudder and elevators are so close to the point of propulsion that it will create an "unstable" motion regime.

It's the other way round, the closer the engines to the centerline of the aircraft, the more stable it is.

Originally Posted by PGA

(...)
Secondly why IAF is flight testing an aeroplane built to civilian specs. Differentiation again about competence and capability is essential.

Military and civil aviation are different domains. While latter is staid and thorough the former is dynamic and result oriented.
Inquiry report is a must read for those wanting to understand if and why's of Saras crash and the huge systemic flaws. In the present ways we are most likely to come up with a great jugaad rather than a world beating and enduring product.
(...)

The IAF already operates several aircraft that are primarily civil-certified

• EMB-145
• Boeing 737
• Training gliders at the NDA (I forget the exact model)
• Do-228

The Saras is not meant to go into combat so civil-specs are perfectly fine.
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.
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Now that I've addressed some points raised by others, I'd just like to state my opinion about the Saras, Tejas and other such indigenous aerospace projects....

We should not aim for perfection or world-leading performance or features in these initial attempts. Treat them as learning experiences and just make sure that they are good enough. Gold-plated product specifications will only lead to endless delays and escalating costs. NAL, DRDO etc. should aim to get and aircraft out of the door which gets the job done - in the case of the Tejas, Saras, Rustom etc. the product is NOT the aircraft, it is the engineers, the staff who will build the next generation of aircraft. It is the infrastructure which will allow the design of the next aircraft to start from the first floor instead of the basement. It is the experience of the mistakes that were made when defining the aircraft's specifications, the mistakes made in the design, the mistakes made in selecting vendors and the mistakes made in the project management. These are the actual products they are making in this first generation of aircraft projects and they should work accordingly.

[V.Narayan]

Originally Posted by vivtho

Now that I've addressed some points raised by others, I'd just like to state my opinion about the Saras, Tejas and other such indigenous aerospace projects....

We should not aim for perfection or world-leading performance or features in these initial attempts. Treat them as learning experiences and just make sure that they are good enough. Gold-plated product specifications will only lead to endless delays and escalating costs. NAL, DRDO etc. should aim to get and aircraft out of the door which gets the job done - in the case of the Tejas, Saras, Rustom etc. the product is NOT the aircraft, it is the engineers, the staff who will build the next generation of aircraft. It is the infrastructure which will allow the design of the next aircraft to start from the first floor instead of the basement. It is the experience of the mistakes that were made when defining the aircraft's specifications, the mistakes made in the design, the mistakes made in selecting vendors and the mistakes made in the project management. These are the actual products they are making in this first generation of aircraft projects and they should work accordingly.

Very wise and thoughtful words.

We would love to benefit with your participation on T-BHP especially the aerospace threads. I recall your post, from 3 years ago, on the ancestry of the Su30MKI. You not only know about aircraft but also the challenges of developing our aerospace foundation.

[vivtho]

Originally Posted by V.Narayan

Very wise and thoughtful words.

We would love to benefit with your participation on T-BHP especially the aerospace threads. I recall your post, from 3 years ago, on the ancestry of the Su30MKI. You not only know about aircraft but also the challenges of developing our aerospace foundation.

Thank you. I am a long-time member of TBHP, it's just that I avoid talking unless I have something worth contributing. However, I will definitely make an effort to contribute more, at least to the aviation-related threads.

[srvm]

Govt. is setting up a high-level task force to develop roadmap for building indigenous aircraft under 'Make-in-India' initiative. If initiated it is expected to cost about 10,000 crores to the exchequer. This was announced by Civil Aviation Minister Suresh Prabhu in Rajya Sabha.
The task force will consist of 106 people from HAL, NAL, ADF and DRDO for appraisal.

Interesting times! After the Regional Transport Aircraft (RTA) and National Civil Aircraft Development (NCAD) programmes/initiatives which never picked up momentum, I wonder if this proposed Special Purpose Vehicle (SPV) will have a different fate?

Complete article here

PS: I wonder what is ADF in the article? Typo for Aeronautical Development Agency (ADA)?
Hope this is the right thread for this post. Else, request mods to move this post to appropriate thread.