Air breathing Engines

Do air breathing engines provide any benefit for vertically launched
spacecraft? I have recently seen work regarding hypersonic aircraft
which purports to have additional benefits of reducing the cost for
space access. Surely this can not be purely justified on the bases of
reduced fuel (oxidiser) payload? In addition shouldn't the low speed
inefficiencies of air breathing engines rule them out as a primary
engine choice?? Finally, wouldn't the rapid rate at which air density
falls with increasing height not make their use limited to at most the
first 100,000 feet??

(Zoltan Szakaly) :

(Stephenjkm) wrote in message
om...
Do air breathing engines provide any benefit for vertically launched
spacecraft? I have recently seen work regarding hypersonic aircraft
which purports to have additional benefits of reducing the cost for
space access. Surely this can not be purely justified on the bases of
reduced fuel (oxidiser) payload? In addition shouldn't the low speed
inefficiencies of air breathing engines rule them out as a primary
engine choice?? Finally, wouldn't the rapid rate at which air density
falls with increasing height not make their use limited to at most the
first 100,000 feet??

I have been working on the development of air breathing engines for
over ten years. I do this for a practical flying car and also for
first stage or booster propulsion. My engines are ramjet like, it
seems to me that they offer significant advanyages between 0 and about
mach 6 to 8. The optimum cutoff depends on the ascent profile as well
as the desired final orbit. There is no penalty at low speeds. The Isp
changes from about 4,000 at standstill to 1,000 at mach 6. In terms of
thrust to weight they are comparable to rocket engines.
It is even possible to use them as rocket engines with the intakes
closed, so there is no weight penalty from having an extra rocket
engine.

The problem is we know you above statements are not true because you have
never flown your engines above mach 1. It does not matter what you hope the
results will be, until you fly them you are just guessing, and very poorly it
seems.

While this may seem like an attack on you, it really is not. I would love to
know see the results of you flying one of your engines above mach 1, and
getting some real numbers back. I am sure that you can get your design to
work at sub mach speeds, it is the way you dismiss shock wave (inlet,
interior, and outlet) considerations that cause me to doubt your expectations
for greater than mach 1 operation.

Please, when are you going to fly one of your designs?

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

(Zoltan Szakaly) :

(Stephenjkm) wrote in message
om...
Do air breathing engines provide any benefit for vertically launched
spacecraft? I have recently seen work regarding hypersonic aircraft
which purports to have additional benefits of reducing the cost for
space access. Surely this can not be purely justified on the bases of
reduced fuel (oxidiser) payload? In addition shouldn't the low speed
inefficiencies of air breathing engines rule them out as a primary
engine choice?? Finally, wouldn't the rapid rate at which air density
falls with increasing height not make their use limited to at most the
first 100,000 feet??

I have been working on the development of air breathing engines for
over ten years. I do this for a practical flying car and also for
first stage or booster propulsion. My engines are ramjet like, it
seems to me that they offer significant advanyages between 0 and about
mach 6 to 8. The optimum cutoff depends on the ascent profile as well
as the desired final orbit. There is no penalty at low speeds. The Isp
changes from about 4,000 at standstill to 1,000 at mach 6. In terms of
thrust to weight they are comparable to rocket engines.
It is even possible to use them as rocket engines with the intakes
closed, so there is no weight penalty from having an extra rocket
engine.

The problem is we know you above statements are not true because you have
never flown your engines above mach 1. It does not matter what you hope the
results will be, until you fly them you are just guessing, and very poorly it
seems.

While this may seem like an attack on you, it really is not. I would love to
know see the results of you flying one of your engines above mach 1, and
getting some real numbers back. I am sure that you can get your design to
work at sub mach speeds, it is the way you dismiss shock wave (inlet,
interior, and outlet) considerations that cause me to doubt your expectations
for greater than mach 1 operation.

Please, when are you going to fly one of your designs?

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

While this may seem like an attack on you, it really is not. I would love to
know see the results of you flying one of your engines above mach 1, and
getting some real numbers back. I am sure that you can get your design to
work at sub mach speeds, it is the way you dismiss shock wave (inlet,
interior, and outlet) considerations that cause me to doubt your expectations
for greater than mach 1 operation.

Please, when are you going to fly one of your designs?

Earl Colby Pottinger

Unfortunately I am slowed down by such mundane issues as finding the
right fitting between the presure regulator and the fuel tank, so I
can feed the vapor fitting with the pressurized helium.

I know my engine works because at higher speeds like mach 0.5 to 6 it
is just like a ramjet, and I have seen a lot of data on those,
including publications quoted here in this group. At static condition
I have data from my own test firings. I can control the fuel air
mixture ratio by varying the pressure and temperature of the fuel
injected, so I can cover a wide range of incoming air conditions.

In my mind there is no point trying to use an air breather above mach
6, so I just assume that my hipothetical launch vehicle would use the
engine as a pure rocket above mach 6. From 0 to mach 6 I have a
ramjet. This way I can predict performance, which indicates that I can
go to LEO with a mass ratio of 6 using propane and LOX. Since a mass
ratio of 10 can be achieved from a structural point of view, I can
have a high payload fraction, or large wings for reentry.

Zoltan

While this may seem like an attack on you, it really is not. I would love to
know see the results of you flying one of your engines above mach 1, and
getting some real numbers back. I am sure that you can get your design to
work at sub mach speeds, it is the way you dismiss shock wave (inlet,
interior, and outlet) considerations that cause me to doubt your expectations
for greater than mach 1 operation.

Please, when are you going to fly one of your designs?

Earl Colby Pottinger

Unfortunately I am slowed down by such mundane issues as finding the
right fitting between the presure regulator and the fuel tank, so I
can feed the vapor fitting with the pressurized helium.

I know my engine works because at higher speeds like mach 0.5 to 6 it
is just like a ramjet, and I have seen a lot of data on those,
including publications quoted here in this group. At static condition
I have data from my own test firings. I can control the fuel air
mixture ratio by varying the pressure and temperature of the fuel
injected, so I can cover a wide range of incoming air conditions.

In my mind there is no point trying to use an air breather above mach
6, so I just assume that my hipothetical launch vehicle would use the
engine as a pure rocket above mach 6. From 0 to mach 6 I have a
ramjet. This way I can predict performance, which indicates that I can
go to LEO with a mass ratio of 6 using propane and LOX. Since a mass
ratio of 10 can be achieved from a structural point of view, I can
have a high payload fraction, or large wings for reentry.

Zoltan

Just read that Pratt and Whitney have made a protoytpe air-breathing Pulse
Detonation jet which'll be good for supersonic planes and atmospheric boosters
for rockets. This will help to perfect PDE rockets which will be simple,
lightweight and robust with an Isp similar to solids. Maybe more research will
boost the Isp?

Surely this can not be purely justified on the bases of
reduced fuel (oxidiser) payload? In addition shouldn't the low speed
inefficiencies of air breathing engines rule them out as a primary
engine choice?? Finally, wouldn't the rapid rate at which air density
falls with increasing height not make their use limited to at most the
first 100,000 feet??
Well, If oxidiser is 1/4 to 1/3 of the weight you're trying to get off the
ground, it makes sense to burn the oxygen in the air. Yes, the air's too thin
to utilise over 100k feet altitude. A pure rocket would have to be on board for
higher altitudes above.that.
^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~

Just read that Pratt and Whitney have made a protoytpe air-breathing Pulse
Detonation jet which'll be good for supersonic planes and atmospheric boosters
for rockets. This will help to perfect PDE rockets which will be simple,
lightweight and robust with an Isp similar to solids. Maybe more research will
boost the Isp?

Surely this can not be purely justified on the bases of
reduced fuel (oxidiser) payload? In addition shouldn't the low speed
inefficiencies of air breathing engines rule them out as a primary
engine choice?? Finally, wouldn't the rapid rate at which air density
falls with increasing height not make their use limited to at most the
first 100,000 feet??
Well, If oxidiser is 1/4 to 1/3 of the weight you're trying to get off the
ground, it makes sense to burn the oxygen in the air. Yes, the air's too thin
to utilise over 100k feet altitude. A pure rocket would have to be on board for
higher altitudes above.that.
^
//^\\
~~~ near space elevator ~~~~
~~~members.aol.com/beanstalkr/~~~

(Zoltan Szakaly) :


While this may seem like an attack on you, it really is not. I would
love to
know see the results of you flying one of your engines above mach 1, and
getting some real numbers back. I am sure that you can get your design
to
work at sub mach speeds, it is the way you dismiss shock wave (inlet,
interior, and outlet) considerations that cause me to doubt your
expectations for greater than mach 1 operation.

Please, when are you going to fly one of your designs?

Earl Colby Pottinger

Unfortunately I am slowed down by such mundane issues as finding the
right fitting between the presure regulator and the fuel tank, so I
can feed the vapor fitting with the pressurized helium.

Mundane issues are the diffirence between viewgraphs and hardware that meets
expectations. Until you solve the mundane issues you don't have a working
design. Instead it is just a test of concept hardware. Please try and get
your unit flying.

I know my engine works because at higher speeds like mach 0.5 to 6 it
is just like a ramjet, and I have seen a lot of data on those,
including publications quoted here in this group. At static condition
I have data from my own test firings. I can control the fuel air
mixture ratio by varying the pressure and temperature of the fuel
injected, so I can cover a wide range of incoming air conditions.

No! You don't know! You have hope, expectations, educated guesses. But
until you fly the hardware you know nothing. Ask the people who built
supersonic hardware about thier hardware and if it did what they expected on
the first try. You try your best to skip over the affects of supersonic
flows/shocks but you can't escape them. Even at 0.6 mach it is possible that
some of the flow in your 'ramjet' design will go that high.

In my mind there is no point trying to use an air breather above mach
6, so I just assume that my hipothetical launch vehicle would use the
engine as a pure rocket above mach 6. From 0 to mach 6 I have a
ramjet. This way I can predict performance, which indicates that I can
go to LEO with a mass ratio of 6 using propane and LOX. Since a mass
ratio of 10 can be achieved from a structural point of view, I can
have a high payload fraction, or large wings for reentry.

Zoltan

Forget mach 6, first prove that you can break mach 1. Until you do that
everything else you claim about your designs are just pipe dream (litereally).

Earl Colby Pottinger


--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

Hi, Just like to say cheers for all the messages :-), they will
certainly keep me thinking. I have one final question, I know that the
Brits have flown a scramjet engine (missile scale model), but, I also
know that the Australians and the Americans (X-43) have had several
attempts. I was just woundering if anybody could tell me who did it
first!

Hi, Just like to say cheers for all the messages :-), they will
certainly keep me thinking. I have one final question, I know that the
Brits have flown a scramjet engine (missile scale model), but, I also
know that the Australians and the Americans (X-43) have had several
attempts. I was just woundering if anybody could tell me who did it
first!