Author Topic: Business and regional jets  (Read 2598 times)

Offline GTX_Admin

  • Evil Administrator bent on taking over the Universe!
  • Administrator - Yep, I'm the one to blame for this place.
  • Whiffing Demi-God!
    • Beyond the Sprues
Re: Business and regional jets
« Reply #30 on: May 06, 2018, 01:24:05 AM »
Go for it!
All hail the God of Frustration!!!

Offline ysi_maniac

  • I will die understanding not this world
Re: Business and regional jets
« Reply #31 on: May 07, 2018, 08:09:30 PM »
 :smiley: OK!

Offline GTX_Admin

  • Evil Administrator bent on taking over the Universe!
  • Administrator - Yep, I'm the one to blame for this place.
  • Whiffing Demi-God!
    • Beyond the Sprues
Re: Business and regional jets
« Reply #32 on: November 29, 2018, 02:21:50 AM »
It started off as a business jet:

https://youtu.be/-MGJnL-Smk4
All hail the God of Frustration!!!

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Business and regional jets
« Reply #33 on: November 29, 2018, 05:43:53 AM »
In the latest issue of Air-Britain's Aviation World, there's an article about a De Havilland (UK) reginal airliner called the D.H.123.  I can't find anything on the internet other than what's on SPF (no pictures), but it looks like a fore runner to a Dash 8

Offline apophenia

  • Suffered two full days of rapid-fire hallucinations and yet had not a single usuable whif concept in the lot !?!
  • Patterns? What patterns?
Re: Business and regional jets
« Reply #34 on: November 29, 2018, 07:39:34 AM »
The powerplant for the D.H.123 - the de Havilland Gnome P.1000 turboprop - had an interesting shaft arrangement. Here is a bit on the P.1000 from Flight 18 March 1960:

"D.H. Gnome P.1000 Free-turbine turboprop. Ten-stage compressor with variable-incidence inlet guide vanes and first three stators, annular combustion chamber with 16 burners, two-stage compressor turbine, independent single-stage power, turbine driving through rear reduction gear, high-speed top shaft and front reduction gear to suit propeller speeds from 1,245 to 1,550 r.p.m. Overall length, 87.3 in; height, 31.55 in; width, 17 in; dry weight, with starter and accessories, 555 lb; mass flow, 12.4 lb/sec; pressure ratio, 8.3:1; max rating (5 min.), 1,000 s.h.p. + 144 lb thrust at 26.260 r.p.m. (20,000 power-turbine r.p.m.) with s.f.c. of 0.669 lb/hr/s.h.p.; recommended cruise, 800 s.h.p. + 120 lb at 25,120/17,000 r.p.m. with s.f.c. of 0.728; the P.1200 will have corresponding ratings of 1,150 and 900 s.h.p. with sf.c. of 0.657 and 0.71.

https://www.flightglobal.com/FlightPDFArchive/1960/1960%20-%200370.PDF

Flight 20 July 1961 reported that "The first P.1000 ran in September 1960, and a Dakota is now being fitted with two of these engines for flight-test purposes." Anyone know if that TurboDak actually flew?

https://www.flightglobal.com/FlightPDFArchive/1961/1961%20-%200980.PDF
Under investigation by the Committee of State Sanctioned Modelling, Alternative History and Tractor Carburettor Production for decadent counterrevolutionary behaviour.

Offline tankmodeler

  • Wisely picking parts of the real universe 2 ignore
Re: Business and regional jets
« Reply #35 on: November 30, 2018, 01:38:05 AM »
The powerplant for the D.H.123 - the de Havilland Gnome P.1000 turboprop - had an interesting shaft arrangement. Here is a bit on the P.1000 from Flight 18 March 1960:

"D.H. Gnome P.1000 Free-turbine turboprop. Ten-stage compressor with variable-incidence inlet guide vanes and first three stators, annular combustion chamber with 16 burners, two-stage compressor turbine, independent single-stage power, turbine driving through rear reduction gear, high-speed top shaft and front reduction gear to suit propeller speeds from 1,245 to 1,550 r.p.m.
The PT6 simplified the whole engine package by doing something non-intuitive, having the air inlet at the back and the exhaust at the front.

It costs you some extra ducting, which, if you do it right can actually act to reduce engine inlet noise, so it's not a total loss, but what that does is puts the free turbine, and the required gearbox, up front, right next to the prop, so there's no extension shaft, no need to sidestep the engine with the prop shaft or to run the prop shaft up inside the turbine. It simplified things amazingly. Everything, from engine build, and test to maintenance and up rating. Compared to previous turboprops PT-6s are incredibly simple engines.

Paul

Offline apophenia

  • Suffered two full days of rapid-fire hallucinations and yet had not a single usuable whif concept in the lot !?!
  • Patterns? What patterns?
Re: Business and regional jets
« Reply #36 on: December 01, 2018, 07:19:30 AM »
Good points Paul. As you say, a reverse-flow arrangement would greatly simplify things ... perhaps explaining to DH why GE never pursued a turboprop T58  ;)
(Actually, that Gnome P.1000 shaft reminded me a little of the PT6T TwinPac  arrangement.)

Maybe de Havilland would have been better off designing a D.H.123 with pusher props?
Under investigation by the Committee of State Sanctioned Modelling, Alternative History and Tractor Carburettor Production for decadent counterrevolutionary behaviour.

Offline GTX_Admin

  • Evil Administrator bent on taking over the Universe!
  • Administrator - Yep, I'm the one to blame for this place.
  • Whiffing Demi-God!
    • Beyond the Sprues
Re: Business and regional jets
« Reply #37 on: December 02, 2018, 01:01:39 AM »
In the latest issue of Air-Britain's Aviation World, there's an article about a De Havilland (UK) reginal airliner called the D.H.123.  I can't find anything on the internet other than what's on SPF (no pictures), but it looks like a fore runner to a Dash 8

I assume the Aviation World article doesn't include any images?
All hail the God of Frustration!!!

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: Business and regional jets
« Reply #38 on: December 02, 2018, 02:55:34 AM »
In the latest issue of Air-Britain's Aviation World, there's an article about a De Havilland (UK) reginal airliner called the D.H.123.  I can't find anything on the internet other than what's on SPF (no pictures), but it looks like a fore runner to a Dash 8

I assume the Aviation World article doesn't include any images?

Actually quite a few, just can't find any on the internet. It's one of those discoveries that might not have been found except for some alert fellow who knew what he was looking at.

Just had a look at the article again, it's four pages long of typical magazine size pages. Some 3-Veiws and a couple of artist impressions. And some seating arrangements. Fellow's name who salvaged the documents is Tony Thatcher.
« Last Edit: December 02, 2018, 05:16:54 AM by kitnut617 »

Offline GTX_Admin

  • Evil Administrator bent on taking over the Universe!
  • Administrator - Yep, I'm the one to blame for this place.
  • Whiffing Demi-God!
    • Beyond the Sprues
Re: Business and regional jets
« Reply #39 on: December 02, 2018, 05:07:12 AM »
Ta - might need to source a copy
All hail the God of Frustration!!!