changing operating limitations

Is it possible to change the operating limitations of your homebuilt
after it has been certified?
Let me take the more extreme case...
I was wondering, if one owned (or bought) an RV3, is it possible to
change the operating limitiations to have a red line of 120 knots, and a
maximum continous RPM that arrives at a speed or 120 knots?
This would potentially make it fit as a sport pilot airplane (when flown
within the operating limitations)


Mike

"pittss1c" wrote

if one owned (or bought) an RV3, is it possible to
change the operating limitiations to have a red line of 120 knots, and a
maximum continous RPM that arrives at a speed or 120 knots?
This would potentially make it fit as a sport pilot airplane (when flown
within the operating limitations)

I have heard it discussed that this would not be allowed, from the point of
just stating a maximum RPM. It has to be a limitation that can not be
overcome by the pilot, without major physical changes to the airframe or
powerplant.

My take is that you could put a fine pitch prop on it, and perhaps a
restrictor plate or throttle linkage that would not allow the engine to make
full HP, so the maximum throttle setting would not allow you to go faster
than the 120 knots.

I believe (IMHO) that a major change in the prop would allow you to change
the operations limitations, but I'm certainly no expert on all of this.
Someone will give their opinion soon, I'm sure.

Will the RV 3 fit in on weight and stall limitations? You can not change
the weight, I believe.
--
Jim in NC

On a somewhat similar vein. As we know one of the limitations of the LSA is
that it must have a fixed or ground adjustable prop. I called the FSDO and
asked this...

The LSA rules states "(7) A fixed or ground-adjustable propeller if a
powered aircraft other than a powered glider."

Assuming the experimental-homebuilt aircraft fits the LSA rules in all other
ways can it have an adjustable prop that is, in normal operation, in flight
adjustable (variable pitch NOT constant speed) if the in-flight
adjustability is either...

A. Marked "Not for in flight use by sport pilot" or similar words

or

B. Made not inflight adjustable on the ground that cannot be made inflight
adjustable in the air?


Their answer was NO to both A (which didn't surprise me) and B (which is
what I really wanted them to say yes to.)


"Morgans" wrote in message
...

"pittss1c" wrote

if one owned (or bought) an RV3, is it possible to
change the operating limitiations to have a red line of 120 knots, and a
maximum continous RPM that arrives at a speed or 120 knots?
This would potentially make it fit as a sport pilot airplane (when flown
within the operating limitations)

I have heard it discussed that this would not be allowed, from the point
of
just stating a maximum RPM. It has to be a limitation that can not be
overcome by the pilot, without major physical changes to the airframe or
powerplant.

My take is that you could put a fine pitch prop on it, and perhaps a
restrictor plate or throttle linkage that would not allow the engine to
make
full HP, so the maximum throttle setting would not allow you to go faster
than the 120 knots.

I believe (IMHO) that a major change in the prop would allow you to change
the operations limitations, but I'm certainly no expert on all of this.
Someone will give their opinion soon, I'm sure.

Will the RV 3 fit in on weight and stall limitations? You can not change
the weight, I believe.
--
Jim in NC

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

I think that all you have to do to make your "Lycoming" into a "pittss1c
Super Advanced Powerplant" is to remove the dataplate from the engine
and attach one made by you. It is now uncertified and you would be free
to do what you want with it.

pittss1c wrote:


"pittss1c" wrote
snip

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