COACC Rocket Engine

[atpollard]

Originally posted by Wm_Humphrey:
The main reason COACC doesn't have volume numbers is because aircraft are mass-limited and are very volume-intensive when assembled due to pesky factors like aerodynamics, lifting surfaces, stabilizer surfaces, etc. Volume isn't a primary concern.

I understand WHY they ignored volume, but an unintended consequence is that I cannot use a COACC Turbojet Engine to power a air cushion vehicle or provide a 'hotrod' boost to an air raft without creating my own volume ... and COACC seems to have ALL of the air breathing engines.

Hard Times is a gold mine of Rocket Engines to install in other vehicles (once you zoom in and squint enough to read it on the CD.)

Even an "airframe" configuration from the basic craft design rules isn't, IMO, a true aircraft capable of generating aerodynamic lift far in excess of its own weight and operating normally with a thrust-to-weight ratio less than one. It just means that it's not a brick, streamlined or otherwise, and failure of the grav generators doesn't equal immediate catastrophe. (All Darrian grav vehicles are airframe configurations!)

I remember seeing more detailed rules on wings and airframes somewhere (it might have been the old Striker). I agree that the MT airframe is a very abstract system, but I have a great deal of sympathy on this issue. How can you develop a simple rule to cover everything from the long slender wings of a glider, the wings of a Cessna, the wings of an F4 Phantom, the wings of a Stealth Bomber and the wings of a Hypersonic Orbital space plane? THAT would almost require a book of it's own that would leave people longing for the simplicity of FF&S.

A set of guidelines for generating wings for different airframes with the effect on maximum and minimum airspeed might be nice, but that should appear in some place like STELLAR REACHES instead of filling the basic rule books. Unfortunately, such a task is well outside my expertise - I would do a poor job of identifying what attributes are important to realism and what is unnecessary complexity. (Although speed and wing area do appear to be inversely related).

 

[Wm_Humphrey]

Originally posted by atpollard:
I understand WHY they ignored volume, but an unintended consequence is that I cannot use a COACC Turbojet Engine to power a air cushion vehicle or provide a 'hotrod' boost to an air raft without creating my own volume ... and COACC seems to have ALL of the air breathing engines.

Yes, now I see where your question is coming from. Here's a nice short answer: The Gas Turbine power plant in the Ref's Manual has a mass of 1 ton per kiloliter. The only difference between a gas turbine powerplant and a basic turbofan engine is that the second turbine on the powerplant drives a generator or external driveshaft whereas the turbofan's second turbine drives the bypass fan to increase the mass of air moved by the engine. So a volume of 1 kL per ton is reasonable from that perspective. On the other hand, you need exterior access, mounts, and larger intake/exhasut ducts for the turbofan, so maybe 1.5 kL per ton is more reasonable. If you're retrofitting/hot-rodding an existing vehicle, you could also make the engine volume add to vehicle volume to represent welding engine pods to the sides.

I remember seeing more detailed rules on wings and airframes somewhere (it might have been the old Striker). I agree that the MT airframe is a very abstract system, but I have a great deal of sympathy on this issue. How can you develop a simple rule to cover everything from the long slender wings of a glider, the wings of a Cessna, the wings of an F4 Phantom, the wings of a Stealth Bomber and the wings of a Hypersonic Orbital space plane? THAT would almost require a book of it's own that would leave people longing for the simplicity of FF&S.

Run away, very, very fast from anything that makes FF&S look simple!

I agree that the MT Ref's Manual is not the place for detailed aircraft design rules - especially not when the vast majority of the non-ground vehicles designed are grav-propelled. If you can have jump drive, you can have grav vehicles - so why on Vland would you want a craft utterly dependent on an atmosphere? No real rules for watercraft there, either, I notice...

But, if you're not seeing what you remember in COACC, it wasn't in Striker. As far as I can tell, the design rules in COACC were lifted almost verbatim out of Striker.

A set of guidelines for generating wings for different airframes with the effect on maximum and minimum airspeed might be nice, but that should appear in some place like STELLAR REACHES instead of filling the basic rule books. ... (Although speed and wing area do appear to be inversely related).

Actually, wing area is related primarily to overall weight. Wing shape (long, straight & thin vs. short, swept-back, and thick) depends primarily on speed range (low-speed vs. super-sonic, respectively). The airframe types in COACC are an attempt to boil all of that down into three or four basic airframe families.

 

[Wm_Humphrey]

Originally posted by atpollard:
I understand WHY they ignored volume, but an unintended consequence is that I cannot use a COACC Turbojet Engine to power a air cushion vehicle or provide a 'hotrod' boost to an air raft without creating my own volume ... and COACC seems to have ALL of the air breathing engines.

Yes, now I see where your question is coming from. Here's a nice short answer: The Gas Turbine power plant in the Ref's Manual has a mass of 1 ton per kiloliter. The only difference between a gas turbine powerplant and a basic turbofan engine is that the second turbine on the powerplant drives a generator or external driveshaft whereas the turbofan's second turbine drives the bypass fan to increase the mass of air moved by the engine. So a volume of 1 kL per ton is reasonable from that perspective. On the other hand, you need exterior access, mounts, and larger intake/exhasut ducts for the turbofan, so maybe 1.5 kL per ton is more reasonable. If you're retrofitting/hot-rodding an existing vehicle, you could also make the engine volume add to vehicle volume to represent welding engine pods to the sides.

I remember seeing more detailed rules on wings and airframes somewhere (it might have been the old Striker). I agree that the MT airframe is a very abstract system, but I have a great deal of sympathy on this issue. How can you develop a simple rule to cover everything from the long slender wings of a glider, the wings of a Cessna, the wings of an F4 Phantom, the wings of a Stealth Bomber and the wings of a Hypersonic Orbital space plane? THAT would almost require a book of it's own that would leave people longing for the simplicity of FF&S.

Run away, very, very fast from anything that makes FF&S look simple!

I agree that the MT Ref's Manual is not the place for detailed aircraft design rules - especially not when the vast majority of the non-ground vehicles designed are grav-propelled. If you can have jump drive, you can have grav vehicles - so why on Vland would you want a craft utterly dependent on an atmosphere? No real rules for watercraft there, either, I notice...

But, if you're not seeing what you remember in COACC, it wasn't in Striker. As far as I can tell, the design rules in COACC were lifted almost verbatim out of Striker.

A set of guidelines for generating wings for different airframes with the effect on maximum and minimum airspeed might be nice, but that should appear in some place like STELLAR REACHES instead of filling the basic rule books. ... (Although speed and wing area do appear to be inversely related).

Actually, wing area is related primarily to overall weight. Wing shape (long, straight & thin vs. short, swept-back, and thick) depends primarily on speed range (low-speed vs. super-sonic, respectively). The airframe types in COACC are an attempt to boil all of that down into three or four basic airframe families.

 

[Wm_Humphrey]

Originally posted by atpollard:
I understand WHY they ignored volume, but an unintended consequence is that I cannot use a COACC Turbojet Engine to power a air cushion vehicle or provide a 'hotrod' boost to an air raft without creating my own volume ... and COACC seems to have ALL of the air breathing engines.

Yes, now I see where your question is coming from. Here's a nice short answer: The Gas Turbine power plant in the Ref's Manual has a mass of 1 ton per kiloliter. The only difference between a gas turbine powerplant and a basic turbofan engine is that the second turbine on the powerplant drives a generator or external driveshaft whereas the turbofan's second turbine drives the bypass fan to increase the mass of air moved by the engine. So a volume of 1 kL per ton is reasonable from that perspective. On the other hand, you need exterior access, mounts, and larger intake/exhasut ducts for the turbofan, so maybe 1.5 kL per ton is more reasonable. If you're retrofitting/hot-rodding an existing vehicle, you could also make the engine volume add to vehicle volume to represent welding engine pods to the sides.

I remember seeing more detailed rules on wings and airframes somewhere (it might have been the old Striker). I agree that the MT airframe is a very abstract system, but I have a great deal of sympathy on this issue. How can you develop a simple rule to cover everything from the long slender wings of a glider, the wings of a Cessna, the wings of an F4 Phantom, the wings of a Stealth Bomber and the wings of a Hypersonic Orbital space plane? THAT would almost require a book of it's own that would leave people longing for the simplicity of FF&S.

Run away, very, very fast from anything that makes FF&S look simple!

I agree that the MT Ref's Manual is not the place for detailed aircraft design rules - especially not when the vast majority of the non-ground vehicles designed are grav-propelled. If you can have jump drive, you can have grav vehicles - so why on Vland would you want a craft utterly dependent on an atmosphere? No real rules for watercraft there, either, I notice...

But, if you're not seeing what you remember in COACC, it wasn't in Striker. As far as I can tell, the design rules in COACC were lifted almost verbatim out of Striker.

A set of guidelines for generating wings for different airframes with the effect on maximum and minimum airspeed might be nice, but that should appear in some place like STELLAR REACHES instead of filling the basic rule books. ... (Although speed and wing area do appear to be inversely related).

Actually, wing area is related primarily to overall weight. Wing shape (long, straight & thin vs. short, swept-back, and thick) depends primarily on speed range (low-speed vs. super-sonic, respectively). The airframe types in COACC are an attempt to boil all of that down into three or four basic airframe families.

 

[sfchbryan]

So much for "tomorrow"!

Had an attack of real life and this got back-burnered. Still working on it, though.

Turns out I already have the CD for MT - what a thing to forget! Also turns out I had started just such a table for myself quite some time ago but never finished it.

Any chance of us seeing that table? I have just about finished up my 4th Ed. Referee's Manual.

 

[DonM]

That sounds like addenda for the errata as well...