Maybe it's better to reduce the speed of jets than to increase the speed of props?
Dornier 328JET. Not a huge success.
We speak about a 3 abreast plane which runs on a business jet engine (PW 306).
The turboprop version first flew 1991, just as Bombardier's CRJ 100. So airlines could choose between a 1,82 m broad cabin DO 328 for hardly 30 passengers or a 2,13 m broad cabin CRJ 100 for up to 50 passengers.
What I find interesting is that the wing was designed for turboprop use with 620 km/ h cruise speed. However the straight wing with few changes can fly with a maximum speed of 750 km/ h in the jet version.
about the original turboprop:
" feedback from airlines indicated a desire for a fast, quiet, and easy-to-maintain commuter airliner with a 30-seat capacity. This market research reportedly led Deutsche Aerospace to formulate a sales prediction of 400 or greater units being purchased overall; this forecast was in part derived from the reasoning that the 328 would be more advanced than its nearest competitors. Favourable features included a high cruising speed of 345 kt (640 km/h), as well as a higher cruising altitude and range, making the aircraft almost as fast as jet airliners while being more fuel-efficient; a trend away from spoke–and-hub distribution in favour of point-to-point transit was also viewed as being favourable to the 328.
having been optimised for high cruising speeds; the aircraft is capable of higher cruise and approach speeds than most turboprop-powered aircraft, which allows it to be more readily slotted around jetliners during landing approaches.
The 328 is furnished with the same supercritical wing design that had been originally developed for Dornier's earlier Do 228; this wing provides the aircraft with both excellent cruise and climb capabilities....The 328 reportedly made greater use of composites than any of its direct competitors at launch, the use of the Kevlar-carbon fiber composites is claimed to have reduced its weight by 20%."https://en.wikipedia.org/wiki/Dornier_328
"The 328JET was designed by Dornier in response to negative feedback from some customers on the marketability of turboprops against the more appealing turbofan engine. It was a relatively straightforward re-reengining of the existing 328
Dornier had planned to conduct a comprehensive upgrade of the existing model, involving an avionics overhaul and possible re-winging to use a new swept wing, around the early 2000s. ... However, a consequence of intense competition within the regional airliner market was multiple manufacturers making losses and terminating their programmes; Fairchild-Dornier were no exception to the industry-wide pressure."https://en.wikipedia.org/wiki/Fairchild_Dornier_328JET
Fairchild Dornier must have figured that 3 abreast is not so good and planned for a six abreast plane.
And some more marketing input from customers:
" The new family of regional jets, the 528JET, 728JET and 928JET, seating from 55 to 100 passengers was launched at the ILA Berlin Aerospace Show (International Aviation and Space Flight Exhibition) in Berlin on 19 May 1998; prior to this, Fairchild Dornier had received provisional launch orders from German flag carrier Lufthansa, who placed 60 firm orders along with 60 options, and Swiss airline Crossair
As a means of preventing low-cost carriers from equipping the 728 with six-abreast seating, instead of Cityline's five-abreast seating, Lufthansa pressured Fairchild Dornier reduce the diameter of the fuselage; this was shrunk from the original 3.40 m (11 ft 2 in) to 3.25 m (10 ft 8 in). The reduction also lowered the weight of the aircraft, but motivated Crossair to move towards the rival Embraer E-Jet family instead; Crossair eventually cancelled their order for the 728, attributing this decision to have been a result of the revised fuselage layout.
Prior to the intended date of the 728's first flight being performed, Fairchild Dornier was rendered insolvent and forced to declare bankruptcy on 2 April 2002. One consequence of this was the whole program being immediately brought to a standstill; shortly thereafter, both Lufthansa and GECAS chose to cancel their orders for the type. The withdrawal of the 728's two biggest customers was a considerable blow to the program, potentially putting off investors and partners that were being sought out at this time."https://en.wikipedia.org/wiki/Fairchild ... 728_family
I think that plane proofs that market studies and customer input are of questionable value. I don't think that plane proofs that low speed jets are not good.