Introduction: Hello everyone.

Morgans wrote:

You no doubt have found that the group will get into mental exercises like
this, and you know what they say about opinions... g

What you want to do is mount a lathe bit on a spring loaded arm. You
pull a lever and cut the prop shaft off. Deploy the chute when you feel
the prop drop off the back.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

Okay Rich, I'll bite. You must have thought up a way to do that,
but it escapes me right now. Explosive bolts like they use in
the space program?

Don W.

Rich S. wrote:
"Don W" wrote in message
. com...


You wouldn't need a brake to get a fully feathering prop to stop. Even
with the propeller stopped it seems that getting the chute to deploy
without snagging risers on the prop would be problematic


Don............

I see you did not pick up on my suggestion, so I'll take it one step
further.

If the *prop* is the problem, jettison the _________. (Fill in the blank)

Rich "Engines are expensive, too." S.

"Don W" wrote in message
om...
Okay Rich, I'll bite. You must have thought up a way to do that,
but it escapes me right now. Explosive bolts like they use in
the space program?

Oh heck, Don. I was just trying to focus your problem solving skills on
where I thought the real problem was. It's not with the engine, of course -
besides, they're too hard to convince that leaving the airframe is the
proper thing to do.

I remember when I was building Esmeralda, I gave a bit of thought on how to
prevent the engine from departing the building in case I should ever toss a
prop blade. CG shift making the airframe unflyable, y'know.

I like the lathe tool idea, but there's others that might work. Since it's a
pusher, the prop would normally like to stay on something like a splined
shaft. You could have a snap-ring retainer that would resist it coming off
during an idling descent. To jettison, a rubbing block would push the snap
ring out of its groove and wind drag would yank the prop back and off the
shaft.

If it is a controllable pitch unit with separate blades, there must be a way
to retain the center section and just lose the blades. I think some of the
composite props have that happen unintentionally!

It would seem that the most elegant solution lies in a prop shroud. No
moving parts, an increase in safety and possible efficiency improvement.

Rich S.

("Rich S." wrote)
To jettison, a rubbing block would push the snap ring out of its groove
and wind drag would yank the prop back and off the shaft.

The Wile E Cyotte in me is seeing a spinning prop (flipped horitontal)
coming back to get me ...and/or the chute lines. Didn't factor that one in,
did ya? :-)

http://img.thefreedictionary.com/thu...e_E_Coyote.jpg


It would seem that the most elegant solution lies in a prop shroud. No
moving parts, an increase in safety and possible efficiency improvement.

I've heard said improvements in efficency, with prop shrouds, haven't
transfered well from the chalkboard to the airframe.

http://www.midwaysailor2.com/blaine/optica.html
OA7 Optica - pusher prop shrouded aircraft.
(ANE) Anoka County-Blaine, MN
D.A.D. Days, 2003


Montblack

"Montblack" wrote in message
...
("Rich S." wrote)
To jettison, a rubbing block would push the snap ring out of its groove
and wind drag would yank the prop back and off the shaft.

The Wile E Cyotte in me is seeing a spinning prop (flipped horitontal)
coming back to get me ...and/or the chute lines. Didn't factor that one
in, did ya? :-)

Zee small parachute for zee prop is trailing out of zee spinner.

It would seem that the most elegant solution lies in a prop shroud. No
moving parts, an increase in safety and possible efficiency improvement.

I've heard said improvements in efficency, with prop shrouds, haven't
transfered well from the chalkboard to the airframe.

I said possible! It depends on who's stating the numbers. . .

http://www.moller.com/

Rich "Wanna see the elepahant??" S

Montblack wrote:
("Rich S." wrote)
It would seem that the most elegant solution lies in a prop shroud. No
moving parts, an increase in safety and possible efficiency improvement.


I've heard said improvements in efficency, with prop shrouds, haven't
transfered well from the chalkboard to the airframe.

http://www.midwaysailor2.com/blaine/optica.html
OA7 Optica - pusher prop shrouded aircraft.
(ANE) Anoka County-Blaine, MN
D.A.D. Days, 2003


Montblack

That is one funky looking airthingamabob!

Don W.

Rich S. wrote:

Oh heck, Don. I was just trying to focus your problem solving skills on
where I thought the real problem was. It's not with the engine, of course -
besides, they're too hard to convince that leaving the airframe is the
proper thing to do.

Yeah, and the other thing is that you usually want them to stay firmly
attached.

I remember when I was building Esmeralda, I gave a bit of thought on how to
prevent the engine from departing the building in case I should ever toss a
prop blade. CG shift making the airframe unflyable, y'know.

Yep, I know of one fatal accident that started with the engine trying to
fly on its own.

I like the lathe tool idea, but there's others that might work. Since it's a
pusher, the prop would normally like to stay on something like a splined
shaft. You could have a snap-ring retainer that would resist it coming off
during an idling descent. To jettison, a rubbing block would push the snap
ring out of its groove and wind drag would yank the prop back and off the
shaft.

If it is a controllable pitch unit with separate blades, there must be a way
to retain the center section and just lose the blades. I think some of the
composite props have that happen unintentionally!

Okay, you just made me think of a way that would work for a controllable
pitch prop. Just make the retainer hub keyed to fit the prop, and when
you rotate the prop just right, it slings its blades.

Check list item: Make sure that the propellor control detent lock is
installed properly. WARNING: NEVER OPERATE THE PROPELLOR CONTROL IN
THE DETENT POSITION EXCEPT IN AN EMERGENCY REQUIRING THE BALLISTIC
CHUTE!!


It would seem that the most elegant solution lies in a prop shroud. No
moving parts, an increase in safety and possible efficiency improvement.

Rich S.

I finally figured out what you mean by a "prop shroud". Duh... Yeah
that could work.

Don W.

"Don W" wrote in message
. com...

I finally figured out what you mean by a "prop shroud". Duh... Yeah
that could work.


Pushy Galore used to have one, but I couldn't find a picture taken before it
was removed.

Rich S.

"Don W" wrote in message
. com...


Tater Schuld wrote:

"Don W" wrote in message
. com...

I'd really like to build something like a pressurized turboVelocity with
the VNE pushed up to 250kts. I'd also like it to have a built in
ballistic chute system which jettisons the engine (to its own chute)
before deployment.


instead of asking us, wouldn't it be wiser to ask the makers of ballistic
chutes?

That makes too much sense ;-) Unfortunately, I don't know any of them
and you guys are readily available. I suspect that if I approached one
of the ballistic chute companys about this they would give me that
"you must be joking, right" look and tell me that ballistic chutes for
pushers is too thin of a market for them to go after.


http://brsparachutes.com/Default.aspx?TabId=18

There's the contact info page from their site. They have them mounted in
pusher ULs already.

Piano hinges with cable instead of wire hold the pod to the rest of the
airframe. Size it to resist the canopy lift load. When you pull the
plug, a spring-loaded reel yanks the cable out. The chute deploys, and
the airplane falls away from you.

Best let go of the stick, since the controls are attached to the
airframe. All that's in the pod are the seats (strap in tight!). The
control panel needs to stay with the airframe, too - waaay too many
quick-disconnects to think about there. One set for the headsets is
doable, but throttle, instruments... of course, with FADEC and a full
glass cockpit all you have is a big honkin multipin plug. No. You
still have the steam gauges as backups, so you still have the
pitot/static connection to deal with.

But now you don't have any structure under you to cushion the impact.
In fact, your feet are hanging out in space a la Fred Flintstone.
Deploy an airbag once forward speed drops?