piston engine powered motorjet
piston engine powered motorjet
(OP)
hi guys,
is anyone familiar with making a motorjet based on a 2 litre gas engine?
is anyone familiar with making a motorjet based on a 2 litre gas engine?
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piston engine powered motorjet
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piston engine powered motorjetpiston engine powered motorjet(OP)
hi guys,
is anyone familiar with making a motorjet based on a 2 litre gas engine? Red Flag SubmittedThank you for helping keep Eng-Tips Forums free from inappropriate posts. Reply To This ThreadPosting in the Eng-Tips forums is a member-only feature.Click Here to join Eng-Tips and talk with other members! |
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RE: piston engine powered motorjet
Mike Halloran
Pembroke Pines, FL, USA
RE: piston engine powered motorjet
wiki below provide some good info motor jet.
http://en.wikipedia.org/wiki/Motorjet
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.
RE: piston engine powered motorjet
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
RE: piston engine powered motorjet
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.............
RE: piston engine powered motorjet
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.
RE: piston engine powered motorjet
http://aardvark.co.nz/pjet/turbine1.htm
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
RE: piston engine powered motorjet
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
RE: piston engine powered 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 !
RE: piston engine powered motorjet
The best source for These APUs is either an aircraft wrecking yard or " Trade A Plane" www.trade-a-plane.com
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.
RE: piston engine powered motorjet
RE: piston engine powered motorjet
Mike Halloran
Pembroke Pines, FL, USA
RE: piston engine powered motorjet
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.