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piston engine powered motorjet 2
- Thread starter mjetbug
- Start date
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1
- #2
MikeHalloran
Mechanical
Please explain what you mean by "motorjet".
Mike Halloran
Pembroke Pines, FL, USA
Mike Halloran
Pembroke Pines, FL, USA
- Thread starter
- #3
hi mike,
wiki below provide some good info motor jet.
anyway, my plan is to use a regular gas/automotive engine to drive turbochargers. The turbochrger blower output would be entirely used to provide jet thrust.
The engine would also be mechanically coupled to a large supercharger to boost its performance.
thus, the engine wouls actually serve as a gas-generator to the turbos.
wiki below provide some good info motor jet.
anyway, my plan is to use a regular gas/automotive engine to drive turbochargers. The turbochrger blower output would be entirely used to provide jet thrust.
The engine would also be mechanically coupled to a large supercharger to boost its performance.
thus, the engine wouls actually serve as a gas-generator to the turbos.
MikeHalloran
Mechanical
Ignoring what I perceive as logical inconsistencies in your implementation, or just don't understand, there's no doubt that the concept works, worked well enough to get into production more than once, and didn't work well enough to stay in production.
Why do you suppose that is?
My guess is that, then, it couldn't match the power density of turbine engines... and now, it couldn't match the long time between maintenance events.
I'd guess it could beat turbine engines on fuel consumption, as can turboprops. Have you got an economic model that predicts if, and at what fuel price, it becomes more attractive than either?
As I see it, you're proposing a technological solution to what is fundamentally an economic problem.
That's like bringing a law book to a knife fight.
Mike Halloran
Pembroke Pines, FL, USA
Why do you suppose that is?
My guess is that, then, it couldn't match the power density of turbine engines... and now, it couldn't match the long time between maintenance events.
I'd guess it could beat turbine engines on fuel consumption, as can turboprops. Have you got an economic model that predicts if, and at what fuel price, it becomes more attractive than either?
As I see it, you're proposing a technological solution to what is fundamentally an economic problem.
That's like bringing a law book to a knife fight.
Mike Halloran
Pembroke Pines, FL, USA
- Thread starter
- #5
well mike, part of your observation is indeed obvious/correct !
ye see, pure-bred turbos, jet or fan can cost a bundle indeed, and my original intent was actually to engineer something that could be put together from parts off the shelf by someone with greasy hands.
and this setup is easily scalable too!
the mech-supercharger is too boost gas engine performance, i.e.: improve overall thrust density.
This arrangement would also take away the delicate thermodynamic relationship that inherently exists in a regular turbojet/fan, i.e.: you could pump whatever amount of fuel into the 'afterburner' without affecting combustion air supply.
the part on fuel economy versus thrust density would probably be a tough nut to crack.....emperical data needed!
actually, I was planning to use such a thruster for my VTOL project.
mike, could you elaborate on the 'logical inconsistancies' bit, please.............
ye see, pure-bred turbos, jet or fan can cost a bundle indeed, and my original intent was actually to engineer something that could be put together from parts off the shelf by someone with greasy hands.
and this setup is easily scalable too!
the mech-supercharger is too boost gas engine performance, i.e.: improve overall thrust density.
This arrangement would also take away the delicate thermodynamic relationship that inherently exists in a regular turbojet/fan, i.e.: you could pump whatever amount of fuel into the 'afterburner' without affecting combustion air supply.
the part on fuel economy versus thrust density would probably be a tough nut to crack.....emperical data needed!
actually, I was planning to use such a thruster for my VTOL project.
mike, could you elaborate on the 'logical inconsistancies' bit, please.............
mjetbug
In the horsepower range you are talking about with a 2 litre engine there are quite a number of used aircraft AP units available at reasonable cost.
Have you considered reworking a unit like this to achieve your goals.
Otherwise you are essentially considering the manufacturing of the hot section of a turbine engine without all of the benefits and most of the dis-advantages.
B.E.
In the horsepower range you are talking about with a 2 litre engine there are quite a number of used aircraft AP units available at reasonable cost.
Have you considered reworking a unit like this to achieve your goals.
Otherwise you are essentially considering the manufacturing of the hot section of a turbine engine without all of the benefits and most of the dis-advantages.
B.E.
swearingen
Civil/Environmental
There's plenty of folks that have taken standard car turbochargers and made jet engines out of them. There is one guy I remember from a while back that did a particularly good job and had several videos showing the progression of his work. After a quick search, I couldn't find his, but I did find this.
The delicate thermodynamic relationship between air supply and fuel delivery is one that is easily solved by trial and error by this guy and many like him. You can keep your costs fairly low as well...
If you "heard" it on the internet, it's guilty until proven innocent. - DCS
The delicate thermodynamic relationship between air supply and fuel delivery is one that is easily solved by trial and error by this guy and many like him. You can keep your costs fairly low as well...
If you "heard" it on the internet, it's guilty until proven innocent. - DCS
MikeHalloran
Mechanical
How many turbochargers do you figure it will take?
Are you planning to drive them with the exhaust gas from the piston engine, or mechanically from the crank?
Mike Halloran
Pembroke Pines, FL, USA
Are you planning to drive them with the exhaust gas from the piston engine, or mechanically from the crank?
Mike Halloran
Pembroke Pines, FL, USA
- Thread starter
- #9
berkshire,
...actually working on that idea, too...in parallel.
any place you know I could get hold of these APUs?
swearingen,
the delicate nature of themodynamic relationship of the whole unit, is precisely why I'm going the motor-jet route!
mike,
..plan is to fit one turbo/cylinder, i.e. 4/engine.
need to work on the cam to....to dump the hot gas earlier.
well guys, for my project, I need 1500 lbs total thrust.
don't really like the idea of using regular props....mechanically complicated.
same goes for ducted fan(s).
ans so....
1. I could use multiple units of microjets(RC model types)
2. -do- small jet.....those used for drones and such.
3. motorjet !
...actually working on that idea, too...in parallel.
any place you know I could get hold of these APUs?
swearingen,
the delicate nature of themodynamic relationship of the whole unit, is precisely why I'm going the motor-jet route!
mike,
..plan is to fit one turbo/cylinder, i.e. 4/engine.
need to work on the cam to....to dump the hot gas earlier.
well guys, for my project, I need 1500 lbs total thrust.
don't really like the idea of using regular props....mechanically complicated.
same goes for ducted fan(s).
ans so....
1. I could use multiple units of microjets(RC model types)
2. -do- small jet.....those used for drones and such.
3. motorjet !
Mjetbug
The best source for These APUs is either an aircraft wrecking yard or " Trade A Plane" They tend to be cyclical, at times there are plenty around then they dry up for a while. You just have to wait and watch.
B.E.
The best source for These APUs is either an aircraft wrecking yard or " Trade A Plane" They tend to be cyclical, at times there are plenty around then they dry up for a while. You just have to wait and watch.
B.E.
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- #11
thruthefence
Aerospace
From my uneducated point of view, this seems like creating an air conditioning system by running a powerful recip engine, and routing the exhaust gas into an aircycle machine. I'm sure it could be done, & cool air would be the result, but it just doesn't seem a very elegant solution. Your name wouldn't be Moller, would it?
MikeHalloran
Mechanical
I don't think you can get enough mass flow to make 1500 lb of thrust with that system.
Mike Halloran
Pembroke Pines, FL, USA
Mike Halloran
Pembroke Pines, FL, USA
- Thread starter
- #13
thanks berkshire.
thruthefence,
nope, there's is Moller in my name....!!!
that thing looks way too bulky..then again, his is a full blown aircraft. what I'm working on is more of a 'rustabout', if you will..
mike,
you're probably right, and that's why I wanted to compare notes with someone who might have done this....
I was looking at the possibility of squeezing much higher heat energy out of stock 2 litre engine...hence the supercharger, much like how we're able to pump out crazy horsepowers from a souped-up motors.
actually guys, like berkshire noted correctly, I'm swapping the hot section of regular turbine motor with something which, in my opinion, is thermodynamically more stable/reliable....and you guys are probably right too..... it is a little more mechanically challenging!
but, then again, its something which is tried and tested.
thruthefence,
nope, there's is Moller in my name....!!!
that thing looks way too bulky..then again, his is a full blown aircraft. what I'm working on is more of a 'rustabout', if you will..
mike,
you're probably right, and that's why I wanted to compare notes with someone who might have done this....
I was looking at the possibility of squeezing much higher heat energy out of stock 2 litre engine...hence the supercharger, much like how we're able to pump out crazy horsepowers from a souped-up motors.
actually guys, like berkshire noted correctly, I'm swapping the hot section of regular turbine motor with something which, in my opinion, is thermodynamically more stable/reliable....and you guys are probably right too..... it is a little more mechanically challenging!
but, then again, its something which is tried and tested.
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