AOA indicator pinout

"Bill Daniels" bildan@comcast-dot-net wrote

For Dan's earlier question about performance at altitude, what I hear from
Bob is that it looks pretty good. His real concern was restarts at
altitude. He made a big improvement in that by switching from glo-plugs
to spark igniters. As I understand it, the micomputer engine controller
senses altitude and adjusts the engine to adapt.

I also hear that the life of the engine, and especially the bearings (the
most prone to need replaced first) have been much improved in many brands of
engines, and that the little engines run happily for many hours.

Some of the engines out there are getting pretty big, and with big thrust
values to go along with it.

I'm thinking that a pair of them would make self launching possible; if not
completely unassisted, with an auto towing down the runway to, say, 30 or 40
feet of altitude?

Then, if a cruise at the same altitude was needed to get home, or whatever,
one could be shut down.
--
Jim in NC

"Morgans" wrote in message
...

"Bill Daniels" bildan@comcast-dot-net wrote

For Dan's earlier question about performance at altitude, what I hear
from Bob is that it looks pretty good. His real concern was restarts at
altitude. He made a big improvement in that by switching from glo-plugs
to spark igniters. As I understand it, the micomputer engine controller
senses altitude and adjusts the engine to adapt.

I also hear that the life of the engine, and especially the bearings (the
most prone to need replaced first) have been much improved in many brands
of engines, and that the little engines run happily for many hours.

Some of the engines out there are getting pretty big, and with big thrust
values to go along with it.

I'm thinking that a pair of them would make self launching possible; if
not completely unassisted, with an auto towing down the runway to, say, 30
or 40 feet of altitude?

Then, if a cruise at the same altitude was needed to get home, or
whatever, one could be shut down.
--
Jim in NC

I think the whole thing is coming together. The neat thing is most of these
engines only cost a few thousand dollars. Yes, they are thirsty but the
sailplane application is unique in that they need not run very long. One
thing seldom mentioned is that these little turbines whine at 150,000 RPM is
way above human hearing. All you hear is the exhaust roar and that isn't
too loud.

Takeoff will be a problem until we get workable afterburners. (It's been
done.) You'd only need the re-heat for a few seconds until liftoff.
Another takeoff aid that has been proposed is a bungee launch.

Although everybody in the know says the jet exhaust from a single piggyback
engine aimed at the fin doesn't do any harm, I'd like a little more
information on that.

Bill Daniels

On Oct 17, 3:26 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"cavelamb himself" wrote in message

...





Bill Daniels wrote:

It's been done. Bob Carlton has an airshow act with a jet sailplane.

Jet sailplanes may well have a real future. Although the specific fuel
efficiency of model airplane dog whistles is terrible, (but improving)
mating them with an extremely efficient airframe seems to work really
well.

Some 'back of the envelope' calcualtions show that a single RC model
microjet in the 50 Lb thrust range would push my glider along at well
over 100 knots. The 75 gallon wing tanks normally used for water ballast
would provide a very nice range. If the 'dog whistle' quits, just
retract it an you still have a 50:1 glide ratio.

Bill Daniels

Bill Daniels

And what might those back of the envelope calculations say about
climb rate???

Not bad, around 300 - 400 FPM.

The problem is the takeoff roll. I would expect that with full tanks at a
gross weight of 1422 pounds, full throttle wouldn't move the glider from a
standstill. Even if the glider started rolling, the wing runner had better
be able to do a 4-minute mile - the acceleration to an airspeed where I had
reasonable aileron authority would take a fair amount of time and distance.
I'd plan to use an aero tow or a winch launch before air-starting the
engines.

Bill Daniels- Hide quoted text -

Think "upper surface blowing" and several across each wing. Does make
retraction a problem though.

In article .com,
John Keeney wrote:

On Oct 17, 3:26 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"cavelamb himself" wrote in message

...





Bill Daniels wrote:

It's been done. Bob Carlton has an airshow act with a jet sailplane.

Jet sailplanes may well have a real future. Although the specific fuel
efficiency of model airplane dog whistles is terrible, (but improving)
mating them with an extremely efficient airframe seems to work really
well.

Some 'back of the envelope' calcualtions show that a single RC model
microjet in the 50 Lb thrust range would push my glider along at well
over 100 knots. The 75 gallon wing tanks normally used for water ballast
would provide a very nice range. If the 'dog whistle' quits, just
retract it an you still have a 50:1 glide ratio.

Bill Daniels

Bill Daniels

And what might those back of the envelope calculations say about
climb rate???

Not bad, around 300 - 400 FPM.

The problem is the takeoff roll. I would expect that with full tanks at a
gross weight of 1422 pounds, full throttle wouldn't move the glider from a
standstill. Even if the glider started rolling, the wing runner had better
be able to do a 4-minute mile - the acceleration to an airspeed where I had
reasonable aileron authority would take a fair amount of time and distance.
I'd plan to use an aero tow or a winch launch before air-starting the
engines.

Bill Daniels- Hide quoted text -

Think "upper surface blowing" and several across each wing. Does make
retraction a problem though.

Think RATO...

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."