Keesje
Quote:
I really like the idea of a 150 seat twin TP-400 powered airliner, but more hard numbers are needed to assess its feasibility.
I don't think we have to go to deep for that one.
How about wading into the shallow part and providing some basic answers? How will you shed the weight? This is the Tech forum, not the brochure-speak dream forum.
I took some data from a nice MIT study of the various relevant efficiencies influencing overall efficiency for different aircraft & propulsion types.
No you didn't. You extrapolated wildly from a graph to guesstimate a desired outcome.
...Turboprop engines tend to be 15-20% more fuel efficient then turbofans. main driver of this is the very high BPR of over 1:30. The engines used on 737 and A320 (CFM56 / V2500) are improved versions of 20-30 year old designs, the limited BPR is only 1:5.
The graph represents aircraft, not engines. I asked about airframe weight, not BPR.
The TP400 with the latest technology build into a blank paper design is probably closer or even over 20%. SFC probably around around .4
How did you derive such a claim?
As you mentioned Turboprops are also structurally more efficient then jet aircraft. This has to do with their limited flight envelope and dedicated short haul passenger design.
I mentioned no such thing. Short haul aircraft are structurally reinforced to handle their high cycle operating environment. This adds weight.
The MIT study you linked to contradicts your statement:
"...RJ's are less structurally efficient than large aircraft, and that TP's in turn are less efficient than RJ's."
These considerations made me conclude a 25 % more fuel efficient operation should be possible with the Propliner compared to e.g. a similar sized 737 or A320.
Time to reconsider what conclusions are possible!
Keesje, there are many highly experienced and knowledgeable aviation professionals willing to contribute meaningfully to your idea if you are willing to engage in a honest dialogue.