Is it static thrust?
If so then this is how much it can lift less total weight of itself if used in vertical direction.
No doubt though this would be at full RPM and at say half the numbers would drop off considerably.
so it could lift 25 lb at half rpm without a problem, just asking but what is static thrust is it just what is the max thrust a turbine can do?
Search for dynamic thrust in google and you will see what difference between static and dynamic is.
A turbine thrust curve is not linear to RPM so at 50% I would not expect 50% thrust.
Static Thrust for vert lifting though is the one you need. You would need a thrust - RPM curve to figure out at 50% rpm what it can lift, etc. Don't know what it is for whatever engine you are using.
No idea about the thrust curve, you need to find one or test an engine (I am sure someone has)
I would expect thrust to be around 20% of max at 50% full rpm though. Would think though that operational speed would be around 75% or max RPM and give 50-70% of full thrust (static)
Don't forget to consider how to compensate for torque. I expect that you will have alot of problems with this if you are considering vertical lift as turbines are slow to react and you would need to balance this torque. Don't quite know how you would do it.
Be careful. Jetcats can not operate vertically for long, the fuel flow and lubrication system is not designed for this.
Far be it for me to discourage ambition, although I feel I need to save you a lot of work and expense!
200 Lb is well out of the range of the available microturbines, and using several just multiplies the crash risk as only one needs to fail at any time for the lot to come down, with all that hot metal around, this would have a very good chance of ending in a nice fire.
Have you calculated the weight of fuel needed?
Gas turbines need spool up time (regardless of manufacturers hype) How is this lag in accel/deccel going to be programmed into any flight system?
As Brian mentioned 1/2 rpm doesn't relate to 1/2 thrust, rpm is incidental to the particular engine design. Off design is normally referred to as percentage of normal full throttle, or (% full mass flow). Presumably you want a thrust variation for control, and as most GTs normal design operation is at about say 80~90% of full power, mean that you would need engines rated at nearer 250 Lb thrust, possibly higher, to be able to regulate them reliably at the required 200 Lb thrust.
Just out of interest there are no torque effects with gas turbines...
I'm quite familiar with these as I've spent the last 12 years developing and testing micro turbines (as a full time hobby)
Forget 200 Lbs, just getting an unladen gt powered vto airframe (reliably) flying under computer control (I mean takeoff, hover, transition to flight, to land) would be an astounding achievement...
ok if turbine are that hard to control would you recommend rotary engine for this type of project.
i have herd that the best power to weight ratio engine are rotary engine, just look at the Sikorsky Cypher made by Sikorsky Aircraft it has just 53 hp made by a rotary engine but it can lift 300-340 lb (136-154 kg)
That aircraft uses a rotor which is a completely different proposition, efficiency will be much higher than with turbojets!
pure Turbojets move a small amount of gas at high velocity which makes them inefficient
A rotor moving a large amount of air at slow velocity is much more efficient, say 2.5 times as a rough idea.
Regardless of type of driving engine, the thrust to weight becomes much better hence lower engine outputs can be used.
No doubt the control in the Cypher is rotor blade pitch adjustment which is a much easier project for computer control.
To drive a rotor It would be hard to beat the efficiency of a piston engine and gearbox, at the size your thinking of. Smaller then electric motors become the ideal solution.
The Cypher looks a good Project' Go for it!!!
so the most efficient engine for this type of project is rotary. Just ask but at what size do turbojet or turbine become more efficient then rotary ,or piston engine and gearbox
the number 200 means 200 Newton hence it can produce a thrust of 20 Kg. in fact the 200SX produces 230 Newtons or about 23 Kg, so it is NOT lbs !!!
Hope that helps