|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Rocket Plane in Level Flight?
Would it be possible to design something like the XCOR Lynx for level
flight, with a rocket but still have a useable range? Let's say a normal cruise speed, size and passenger capacity competitive with a Lear Jet 23, or a Cirrus Vision. |
#2
|
|||
|
|||
Rocket Plane in Level Flight?
Justin wrote:
Would it be possible to design something like the XCOR Lynx for level flight, with a rocket but still have a useable range? Let's say a normal cruise speed, size and passenger capacity competitive with a Lear Jet 23, or a Cirrus Vision. My take on this is that you *could* build one with a longer range, but it would not be economical to do so because of the added expense of carrying around all that oxidizer, and certainly not for whatever you are defining as 'normal cruise speed' for a Lear or a Cirrus. In other words it would be more expensive to fly than the Lear/Cirrus. In fact it would aways be more expensive to fly that an air breather. So unless there was some other distinct advantage (like hypersonic speed), there would be no point to doing it. SABRE technology excluded here.... Dave |
#3
|
|||
|
|||
Rocket Plane in Level Flight?
|
#4
|
|||
|
|||
Rocket Plane in Level Flight?
On 3/6/12 2:27 PM, David Spain wrote:
Justin wrote: Would it be possible to design something like the XCOR Lynx for level flight, with a rocket but still have a useable range? Let's say a normal cruise speed, size and passenger capacity competitive with a Lear Jet 23, or a Cirrus Vision. My take on this is that you *could* build one with a longer range, but it would not be economical to do so because of the added expense of carrying around all that oxidizer, and certainly not for whatever you are defining as 'normal cruise speed' for a Lear or a Cirrus. In other words it would be more expensive to fly than the Lear/Cirrus. In fact it would aways be more expensive to fly that an air breather. So unless there was some other distinct advantage (like hypersonic speed), there would be no point to doing it. SABRE technology excluded here.... Dave I had to look up SABRE. Let's bring SABRE into the mix. Would it be possible to desich a rocket to use the atmospheric O2 when available and then switch to an on board supply? |
#5
|
|||
|
|||
Rocket Plane in Level Flight?
|
#6
|
|||
|
|||
Rocket Plane in Level Flight?
On Mar 7, 2:26 am, Justin wrote:
Let's bring SABRE into the mix. Would it be possible to desich a rocke t to use the atmospheric O2 when available and then switch to an on board supply? Yes, it is possible. It won't be competitive with turbofans for atmospheric cruising, though. Rockets and turbojets waste a lot of horsepower that turbofans and turboprops capture. It might help to have some more explanation. I read your initial post asking for a usable range, normal cruise speed, size, etc. But what do you want to do with this rocket plane? (Don't hold back - I've posed some odd thought experiments on usenet, too.) Is it a suborbital tourist rocket that can self-ferry to the boost point? Is it trying to be a faster (hypersonic?) Lear jet? Or are you after a typical business jet with an alternative propulsion system? Or do you want a ground-to-orbit spaceplane? Mike Miller, Materials Engineer |
#7
|
|||
|
|||
Rocket Plane in Level Flight?
|
#9
|
|||
|
|||
Rocket Plane in Level Flight?
On Mar 21, 7:47 pm, Justin
wrote: On 3/12/12 8:34 AM, wrote: On Mar 7, 2:26 am, wrote : Let's bring SABRE into the mix. Would it be possible to desich a ro cke t to use the atmospheric O2 when available and then switch to an on boar d supply? Yes, it is possible. It won't be competitive with turbofans for atmospheric cruising, though. Rockets and turbojets waste a lot of horsepower that turbofans and turboprops capture. Sorry for the delay, been traveling for job interviews! I think I understand. A rocket wouldn't be cost effective for atmospheric travel - even those SABRE's that I just wikied! Why carry your O2 when you can pull it out of the air? It might help to have some more explanation. I read your initial post asking for a usable range, normal cruise speed, size, etc. But what do you want to do with this rocket plane? (Don't hold back - I've posed some odd thought experiments on usenet, too.) It's embarrassing... But here goes! I was at an interview in February and the guy I interviewed with has a model plane on hie desk. It looked like a mini space shuttle. It tu rns out it was a "Farscape" toy! I downloaded a few episodes and I have to say the show sucked, but that rocket plane mini shuttle thing looked pretty neat. From what you, Dave and Jeff said, something that small wouldn't be able to carry enough fuel and O2. I was just wondering if we were even remotely capable of a craft that small capable of air and space flight. There was a scene where the pilot took the craft into an atmosphere and did a dogfight. A jet engine gets oxygen from the atmosphere, but much more importantly, it gets reaction mass. Using rocket fuel at a high exhaust velocity is much less efficient than using jet exhaust at lower velocity. In fact, modern engines are fanjets - basically shrouded propellers - and are twice as efficient as earlier turbojets which had higher exhaust velocity. John Halpenny |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
First rocket plane photo | Pat Flannery | Policy | 0 | October 17th 08 12:07 AM |
First rocket plane photo | Pat Flannery | History | 0 | October 17th 08 12:07 AM |
Private Rocket SpaceShipOne Makes Third Rocket-Powered Flight | Rusty B | Policy | 10 | May 16th 04 02:39 AM |
Private Rocket SpaceShipOne Makes Third Rocket-Powered Flight | Rusty B | Space Shuttle | 1 | May 14th 04 08:46 AM |
Vacuum vs. sea-level rocket engine Isp | Zoltan Szakaly | Technology | 1 | January 25th 04 02:31 AM |