Small turbines for homebuilts?

Bill Daniels wrote:


"ventus2" wrote in message
...
David,

Not competing with high horsepower output like your top Lycombings or
Conti;s but interesting nevertheless.
Check out http://www.tjt.bz/ as these engines are being used very
successfully in gliders at the moment. No idea on performance figures,
fuel
burn etc.

Chris


These little centrifugal turbojets are very inefficient consuming about
10GPH of Jet A for 50 pounds of thrust. Still, they are very cool.


There 30lb thrust model specs at 5.5 gal/hour (350ml/min) which isn't
horrible for a jet. At speed 30lb is roughly 30hp so it takes 3.3 times to
get 100hp so 18 gal/hour which is about 3 times more fuel than a ricip but
it sure could be a lot of fun ;-)
John

"John" wrote in message
...
Bill Daniels wrote:


"ventus2" wrote in message
...
David,

Not competing with high horsepower output like your top Lycombings or
Conti;s but interesting nevertheless.
Check out http://www.tjt.bz/ as these engines are being used very
successfully in gliders at the moment. No idea on performance figures,
fuel
burn etc.

Chris


These little centrifugal turbojets are very inefficient consuming about
10GPH of Jet A for 50 pounds of thrust. Still, they are very cool.


There 30lb thrust model specs at 5.5 gal/hour (350ml/min) which isn't
horrible for a jet. At speed 30lb is roughly 30hp so it takes 3.3 times to
get 100hp so 18 gal/hour which is about 3 times more fuel than a ricip but
it sure could be a lot of fun ;-)
John

If I recall correctly, one pound of thrust = one HP at around 325 knots.
That's quite a bit of 'at speed'.

Bill Daniels wrote:

There 30lb thrust model specs at 5.5 gal/hour (350ml/min) which isn't
horrible for a jet. At speed 30lb is roughly 30hp so it takes 3.3 times
to get 100hp so 18 gal/hour which is about 3 times more fuel than a ricip
but it sure could be a lot of fun ;-)
John

If I recall correctly, one pound of thrust = one HP at around 325 knots.
That's quite a bit of 'at speed'.

That sounds about right, I didn't have the figures in front of me. Even so
if you slowed it down to 150-200 you'd still have a fairly potent engine
for the weight. And it still would be a blast!
John

John wrote:
Bill Daniels wrote:

There 30lb thrust model specs at 5.5 gal/hour (350ml/min) which isn't
horrible for a jet. At speed 30lb is roughly 30hp so it takes 3.3 times
to get 100hp so 18 gal/hour which is about 3 times more fuel than a ricip
but it sure could be a lot of fun ;-)
John
If I recall correctly, one pound of thrust = one HP at around 325 knots.
That's quite a bit of 'at speed'.

That sounds about right, I didn't have the figures in front of me. Even so
if you slowed it down to 150-200 you'd still have a fairly potent engine
for the weight. And it still would be a blast!

Yep, 375mph (or 325 knots). If you factor in propeller efficiency, it's
lower. The math is pretty simple if you know the prop efficiency
(usually about 80% or so), you multiply the two, so in reality the magic
number is about 300mph or between about 250-275 knots.

In other words, a 100hp engine makes 200 pounds of thrust at about
150mph, 100 lbf at 300mph, 50 lbf at 600mph (and so on, putting it
simply). Or, a 30 lb thrust engine is equivalent to a 15hp prop job at
150mph, 30hp at 300mph...

Quite a bit of "at speed."

Static thrust comparisons are a little more complicated, that depends a
lot on the propeller.