changing operating limitations

Morgans wrote:
"pittss1c" wrote
snip
Will the RV 3 fit in on weight and stall limitations? You can not change
the weight, I believe.

stall is 51 MPH, so it just fits the 45 knot rule (VGs might get it lower)

It is about 700-750# empty and 1100 gross as stock.
I was just thinking, the designer sets the operating limitations of a
homebuilt's engine.
therefore one could define an engine based on lycoming parts (up to 100%
lycoming) to have a max continous RPM of...say 2000. (as part of "your"
design to get a higher TBO)

If I was to build up an engine with parts out of my garage, I would set
the operating limitations, and would set the Vne of my own design/airplane.

Mike

"pittss1c" wrote

to have a max continous RPM of...say 2000. (as part of "your"
design to get a higher TBO)

It will not be allowed. The rule plainly states that it is not to exceed
120 knots at wide open throttle.

You have to make it so that if you push any harder on the throttle, it will
break off! g

Sorry. If it were only so.
--
Jim in NC

"Morgans" wrote in message
...

"pittss1c" wrote

to have a max continous RPM of...say 2000. (as part of "your"
design to get a higher TBO)

It will not be allowed. The rule plainly states that it is not to exceed
120 knots at wide open throttle.

You have to make it so that if you push any harder on the throttle, it
will
break off! g

Sorry. If it were only so.
--
Jim in NC

In the spirit of discussion, how about a throttle stop that prevents more
than a certain amount of throttle movement?

KB

"Kyle Boatright" wrote

In the spirit of discussion, how about a throttle stop that prevents more
than a certain amount of throttle movement?

From what I have read, as long as the stop is not defeatable (especially
while in flight) it should pass.

For the real answers to your queries, contact your local FSDO.
--
Jim in NC

On Mon, 15 Aug 2005 20:21:57 -0400, "Morgans"
wrote:

"pittss1c" wrote

to have a max continous RPM of...say 2000. (as part of "your"
design to get a higher TBO)

It will not be allowed. The rule plainly states that it is not to exceed
120 knots at wide open throttle.

I'd certainly like for a citation on that one. While neither a pilot
or a builder, I follow the Sonex site; their plane with the Jab 3300,
at WOT, greatly exceeds limits. As they understand it, the rule is
"Maximum speed in level flight with maximum continuous power (Vh) of
not more than 120 kts (138 mph) CAS under standard atmospheric
conditions at sea level." The word "continuous" is in there ... the
3300 Jabiru is specified at 2750 RPM max continuous which keeps things
legal. Many of the owners report significantly higher capability ...
and maximum RPM is specified, IIRC, at 3300.

"GeorgeB" wrote

I'd certainly like for a citation on that one. While neither a pilot
or a builder, I follow the Sonex site; their plane with the Jab 3300,
at WOT, greatly exceeds limits.

You are right on that, I believe. At one time it was stated as WOT.

As they understand it, the rule is
"Maximum speed in level flight with maximum continuous power (Vh) of
not more than 120 kts (138 mph) CAS under standard atmospheric
conditions at sea level." The word "continuous" is in there ... the
3300 Jabiru is specified at 2750 RPM max continuous which keeps things
legal. Many of the owners report significantly higher capability ...
and maximum RPM is specified, IIRC, at 3300.

I think you have the key here, when you say the Jab engine is rated for 2700
continuous. (by the manufacturer) That is in line with other direct drive
RPMs. The higher RPM's can be done with that engine, but just like the
other major direct drive makers, you can not run them for long at those
speeds, without some consequences.

If you took a Lycoming, and said you were going to limit it for continuous
operation at 2,000 RPM, that would not fly for the sport plane restrictions.
They (the FAA) all know that this engine can run much faster than that, with
no harm. So you are told to try again; no dice.

It seems if you have a homebrew engine, you have an advantage, because you
are the one that will set the continuous operating RPM's. That is my take,
anyway.

Sorry about the WOT bit. Best be having the WOT close to the continuous
RPM, if you want to have a chance of passing, IMHO.

A lot of these things are unknown, since the envelope has not yet been
pushed, and case precedents have not been established, yet. We will have to
wait and see how much they will let us get away with. g
--
Jim in NC

X-No-Archive

"Morgans" wrote in message
...

If you took a Lycoming, and said you were going to limit it for continuous
operation at 2,000 RPM, that would not fly for the sport plane
restrictions.
They (the FAA) all know that this engine can run much faster than that,
with
no harm. So you are told to try again; no dice.

Jim...........

There are many factors besides engine operating parameters which limit
cruising speed. In some aircraft it may be control surface flutter, others
may be subject to overstress by outside aerodynamic forces (hence
maneuvering speed). While an engine may be capable of driving an airframe at
speeds in excess of 120 knots, the airframe itself may be beyond it's
limits.

The fellow who is holding the stick has the legal responsibility for setting
the limits of safe operation on every flight. Just because a designer says
it can do more, doesn't mean it will. That's what test periods are for.

Let's not become our own worst enemy here by espousing a rule that few
people think makes any sense at all -outside the group of new LSA
manufacturers who stand to make a buck selling their airplanes. I'm not
talking about the speed limit, BTW. I'm talking about the "You crossed the
line and can't go back" clause.

Rich S.

I'm not sure of what to do with your post. I can't argue with anything in
it, but it is not very relevant to what the OP was asking about.

If I am remembering correctly, he asked about getting an RV-3 in under the
SP rule. It would not have any problem with flutter, or structure, I think
it is safe to say.

Sure, you could fly past the rule limits, but at some point in time,
(probably when the pilot screws up, and the FAA is investigating) it has to
make the muckety-mucks happy, that it is SP legal. That is the only
question at issue, I think.
--
Jim in NC

"Rich S." wrote in message
...
X-No-Archive

"Morgans" wrote in message
...

If you took a Lycoming, and said you were going to limit it for
continuous
operation at 2,000 RPM, that would not fly for the sport plane
restrictions.
They (the FAA) all know that this engine can run much faster than that,
with
no harm. So you are told to try again; no dice.

Jim...........

There are many factors besides engine operating parameters which limit
cruising speed. In some aircraft it may be control surface flutter, others
may be subject to overstress by outside aerodynamic forces (hence
maneuvering speed). While an engine may be capable of driving an airframe
at
speeds in excess of 120 knots, the airframe itself may be beyond it's
limits.

The fellow who is holding the stick has the legal responsibility for
setting
the limits of safe operation on every flight. Just because a designer says
it can do more, doesn't mean it will. That's what test periods are for.

Let's not become our own worst enemy here by espousing a rule that few
people think makes any sense at all -outside the group of new LSA
manufacturers who stand to make a buck selling their airplanes. I'm not
talking about the speed limit, BTW. I'm talking about the "You crossed the
line and can't go back" clause.

Rich S.

"Morgans" wrote in message
...
I'm not sure of what to do with your post. I can't argue with anything in
it, but it is not very relevant to what the OP was asking about.

If I am remembering correctly, he asked about getting an RV-3 in under the
SP rule. It would not have any problem with flutter, or structure, I
think
it is safe to say.

Sure, you could fly past the rule limits, but at some point in time,
(probably when the pilot screws up, and the FAA is investigating) it has
to
make the muckety-mucks happy, that it is SP legal. That is the only
question at issue, I think.

I guess all I mean is - as long as we don't squeak, another wheel will get
greased. )

Perhaps an RV-3 with a 10" pitch prop could qualify, and hover.

Thanks for not quoting me.

Rich S.

Jim,
I have spoken to a few Sonex builders /owners and they pretty much all
agree the best way to stay in the sport pilot class with a Sonex is to use a
VW powerplant and a climb prop, a cruise prop on the VW still puts you over
the cruise speed. It's a sharp little plane!

Patrick
student SPL
aircraft structural mech

"Morgans" wrote in message
...

"GeorgeB" wrote

I'd certainly like for a citation on that one. While neither a pilot
or a builder, I follow the Sonex site; their plane with the Jab 3300,
at WOT, greatly exceeds limits.

You are right on that, I believe. At one time it was stated as WOT.

As they understand it, the rule is
"Maximum speed in level flight with maximum continuous power (Vh) of
not more than 120 kts (138 mph) CAS under standard atmospheric
conditions at sea level." The word "continuous" is in there ... the
3300 Jabiru is specified at 2750 RPM max continuous which keeps things
legal. Many of the owners report significantly higher capability ...
and maximum RPM is specified, IIRC, at 3300.

I think you have the key here, when you say the Jab engine is rated for
2700
continuous. (by the manufacturer) That is in line with other direct drive
RPMs. The higher RPM's can be done with that engine, but just like the
other major direct drive makers, you can not run them for long at those
speeds, without some consequences.

If you took a Lycoming, and said you were going to limit it for continuous
operation at 2,000 RPM, that would not fly for the sport plane
restrictions.
They (the FAA) all know that this engine can run much faster than that,
with
no harm. So you are told to try again; no dice.

It seems if you have a homebrew engine, you have an advantage, because you
are the one that will set the continuous operating RPM's. That is my
take,
anyway.

Sorry about the WOT bit. Best be having the WOT close to the continuous
RPM, if you want to have a chance of passing, IMHO.

A lot of these things are unknown, since the envelope has not yet been
pushed, and case precedents have not been established, yet. We will have
to
wait and see how much they will let us get away with. g
--
Jim in NC