Got the bug to build a supersonic transport airliner.

[Dave_67]

Originally Posted by Fred Brackin

If you do use Ve2 to make a Concorde you'll have to be up on the afterburners rules. Concorde used 1960s (TL7) fighter jet engines with the afterburners running all the way. If you calculate fuel use that way you'll probably get a ridiculous number but Concorde really did carry that much fuel. That's why it went out of business.

I remember you had said something about turbo-ramjets and that might get around the afterburner problem though the SR-71 gulped fuel too. TL8 technologies generally might be necessary to make this thing more sensible.

I'm not sure about STOL wings with a Lifting Body. It makes an odd picture in my mind's eye. It might not be necessary anyway. Ve2 loves lifting bodies.

Doing some quick calculations, it looks like a TL7 turbofan with afterburner would be slightly more fuel efficient then a TL7 turbo-ramjet with the same.

The 2nd generation of Concorde, with better engines that did not need the afterburner, were already on the drawing board in the 80's/90's, but never went beyond that.

As for using STOL with a lifting body, I was thinking that was probably the closest I could get to designing a delta wing design, especially with the high degree of streamlining. Also, STOL are treated as having 1.5 times their surface area for purposes of calculating static lift.

[Fred Brackin]

Originally Posted by Dave_67

As for using STOL with a lifting body, I was thinking that was probably the closest I could get to designing a delta wing design, especially with the high degree of streamlining. t.

"Delta wing" is one of the normal shape options for the very highest levels of streamlining. No special measures necessary. Usually you don't use wings at all on a lifting body though I guess it's not illegal so much as terribly expensive.

However, I did look it up and STOL wings with that sort of streamlining can represent small canards forward. Those were seen on the XB-70s so they're not out of the question.

The hoped for engines for a Concorde II may have been something like the variable bypass turbofans seen on the F-22. That did appear in prototype form in the 90s but wasn't deployed until after the 3e TL8 line and is probably TL8 tech. Variable bypass engines may be in one of the expansions.

[Dave_67]

Originally Posted by Fred Brackin

"Delta wing" is one of the normal shape options for the very highest levels of streamlining. No special measures necessary. Usually you don't use wings at all on a lifting body though I guess it's not illegal so much as terribly expensive.

However, I did look it up and STOL wings with that sort of streamlining can represent small canards forward. Those were seen on the XB-70s so they're not out of the question.

The hoped for engines for a Concorde II may have been something like the variable bypass turbofans seen on the F-22. That did appear in prototype form in the 90s but wasn't deployed until after the 3e TL8 line and is probably TL8 tech. Variable bypass engines may be in one of the expansions.

The mention of the canards was why I chose the STOL option.

Yeah, that does sound like that could be the case. I recall there was a rule that advanced tech could be had - say, early TL8 at late TL7 - but I wasn't able to find it from a quick perusal. The only reference I found was in Vehicle Lite, and there it only mentioned extra cost. Were there rules for added weight as well?

(Then again, seeing how technology advanced more rapidly compared to the estimates of the writers in the 80's and 90's, I can see why the tech levels were played around with in 4e.)

[johndallman]

Originally Posted by Fred Brackin

Concorde . . . with the afterburners running all the way. If you calculate fuel use that way you'll probably get a ridiculous number but Concorde really did carry that much fuel. That's why it went out of business.

Ah, no. The afterburners were used at takeoff, and in accelerating past Mach 1, but it could cruise supersonically without them. Concorde was retired because Airbus, who had bought the original manufacturers, was unwilling to continue to supply replacement parts. There were never many Concordes and they'd never been updated very much. Maintaining the parts supply-chain just got too expensive. There was also less demand after the crash in Paris, and 9/11.

You may be getting it mixed up with the Tu-144, which did need afterburners to stay supersonic. That was one of the things that meant the Tupolev had a very short service life: use of afterburners means it was short-ranged and the noise level in the cabin was unbearable for passengers. It was also horribly unreliable.

The Tu-144 did have canards for low-speed control. Its aerodynamic design was less optimised than Concorde's, which was one of the reasons it needed afterburners all the time. The Royal Aircraft Establishment had recruited some German aerodynamicists after WWII, notably Johanna Weber and Dietrich Küchemann, and they'd spent much of the decade before the Concorde project started finding out how best to build an SST.

Part of the reason Concorde worked was that it avoided the parts that make the job much harder, such as going too fast for an aluminium skin to take. The US SST project tried for Mach 3, which needs better materials.

[Rupert]

Originally Posted by Dave_67

While continuing to work on my Dixie-7 world, I found myself wanting to go down another rabbit hole and work on putting together an SST airliner - ala the Concorde, Tupolev Tu-144, Boeing 2702, or Lockheed L-2000 - for the DC-25 stratoliner in Dixie-1. However, I'm waffling on HOW to build it.

I've looked around the forums, but haven't found anyone else who has put one together with GURPS Vehicles - or maybe someone has, but has not bothered posting the specs here. I'm thinking the following:

-STOL wings
-Superior or Excellent streamlining with a lifting body
-4 turbo-ramjet engines

Thoughts?

On the GURPSnet mailing list, Onoo Mayer has been doing VE2 'Vehicle of the Week' for ages, and apparently did a military SST at some point, but I couldn't find it. However, he kindly did up one that's basically the Concorde.

Originally Posted by Onno Mayer

Supersonic Transport (Western Model) v1.0 (Early TL7)
Copyright 2018 by Onno Meyer

The Supersonic Transport (SST) was an optimistic design from an
optimistic time. Many orders were cancelled before it entered service,
reflecting high costs and operational challenges like the sonic boom.
The aircraft has a cockpit with seats for two pilots, one engineer,
and two extras. Next come the entry/galley area, the first part of the
passenger cabin, another galley area, the second part of the passenger
cabin, and finally another crew area with the aft luggage hold. There
are 108 passenger seats in a typical configuration.
The engines burn 11,160 gallons of jet fuel per hour at 1,210 mph. A
full load of fuel is $94,500.

Subassemblies: Body +7, ten Retractable Wheels +2, two Wings +5, two
Pods +3.
Powertrain: Four 31,000-lbs. afterburning turbojets; 3,000-kWs lead-acid
batteries.
Fuel: 31,500 gallons jet fuel (fire on 13).
Occ: 4 RCS, 6 folding NS, 108 NS (all with superior access).
Cargo: 600 cf.

Armor F RL B T U
All: 3/8 3/8 3/8 3/8 3/8

Equipment:
Body: Two very-long-range radios; 20-mile air search radar, no
targeting; two flight recorders; two sets of precision navigation
instruments; two transponders; three inertial navigation systems; two
autopilots; two full fire suppression systems; six small galleys; three
roomy toilets with superior access; 154x6 man-hour limited life system.

Statistics
Size: 202'x84'x40' Payload: 231,350 lbs. Lwt.: 409,120 lbs.
Volume: 19,159.4 cf Maint.: 32 man-hours Price: $45,481,175

HT: 11. HPs: 12,000 Body, 300 each Wheel, 5,400 each Wing, 750 each
Pod.

gSpeed: 265 gAccel: 15 gDecel: 10 gMR: 0.25 gSR: 5
Ground Pressure Extremely High. No Off-Road Speed.

aSpeed: 1,855 aAccel: 9 aDecel: 22 aMR: 5.5 aSR: 6
Stall Speed 170. Ceiling 19,100 yards (aerodynamic limit).

Design Notes
The nominal performance assumes sustained use of the afterburner. It
was intended for periods of climb and acceleration only, reducing top
speed to 1,515 mph. The statistics are calculated with 3,000 lbs. of
cargo in addition to cabin luggage.
Body is 13,932 cf, with excellent streamlining. Wheels are 696.6 cf,
retract into Body. Wings are 2,400 cf each. Pods are 213.7 cf each.
Structure is heavy, standard. Armor is standard metal. Sealed.
Electronic controls with duplicate maneuver controls. 594.1 cf of empty
space in the Body and 263 cf in each Wing. Empty weight is 177,770 lbs.
The vehicle uses the design rules from Vehicles [second edition, third
printing, July 2010 errata], VXi, and VXii (including the armor volume,
stall speed, and ceiling rules) with the text format from Vehicles Lite.

[Dave_67]

Originally Posted by Rupert

On the GURPSnet mailing list, Onoo Mayer has been doing VE2 'Vehicle of the Week' for ages, and apparently did a military SST at some point, but I couldn't find it. However, he kindly did up one that's basically the Concorde.

THANK YOU! This seems to be a good starting point to plug in the numbers from.