Hi All.
Just wondering if there are any props out there that can be used on an
experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a beta
range. Don't even want to consider a certified unit as this would probably
cost more than the rest of the firewall forward components.
Thanks in advance,
Rob.
Melbourne Australia.

I believe both the Woodcomp and the IVO will go into Beta.


"Rob Fonhof" > wrote in message
...
> Hi All.
> Just wondering if there are any props out there that can be used on an
> experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a beta
> range. Don't even want to consider a certified unit as this would
> probably cost more than the rest of the firewall forward components.
> Thanks in advance,
> Rob.
> Melbourne Australia.
>

I believe you are mistaken on the IVO.

The IVO has a specific range of travel that is accomplished by twisting
the blade midshaft, not rotating the entire blade in the hub.

Also, with the auto engines the original poster is discussing, it is
less a function of the engine and more a function of will the PSRU
(re-drive) support a hydraulic governor. The Marcotte and Mistral PSRU's
will support a hydraulic constant speed prop, others such as the Real
World Solutions brand will not.

An electric MT can be obtained that will run in the beta (and even
reverse) ranges, but that is a $10k US proposition. Of course, getting a
hydraulic governor, the price difference for a redrive that supports
one, and getting a hydraulic CS prop, you are likely there with the cost
of an Electric MT in the first place.

It costs money.. plain and simple.

The IVO may be an option for you, but as for a specific "beta" range, I
am fairly sure it doesnt have one.


Dave

Gig 601XL Builder wrote:
> I believe both the Woodcomp and the IVO will go into Beta.
>
>
> "Rob Fonhof" > wrote in message
> ...
>
>>Hi All.
>>Just wondering if there are any props out there that can be used on an
>>experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a beta
>>range. Don't even want to consider a certified unit as this would
>>probably cost more than the rest of the firewall forward components.
>>Thanks in advance,
>>Rob.
>>Melbourne Australia.
>>
>
>
>

Also if you are seriously contemplating the use of a rotary (RX7 or
RX8), I would seriously recommend subscribing to one or both of the two
listserv's or newsletters out there:

FlyRotary: http://www.flyrotary.com/ , web archive viewable at
http://lancaironline.net/lists/flyrotary/List.html

This is the list where people are DOING things (more practical oriented)
and is a little less moderated.

Rotary Engine Newsletter, formerly the Aircraft Rotary Engine Newsletter:
http://www.rotaryeng.net

This is closely moderated by an engineering type in California, who
reviews each post before forwarding it. The focus here is much more
theoretical, and skewed toward peripheral ported rotary engines. On more
than one occasion the moderator has stated how something will "not work"
based on theory and analyses, only to have someone on the other list be
"doing it". Still worth following tho.

Dave

Dave S wrote:
> I believe you are mistaken on the IVO.
>
> The IVO has a specific range of travel that is accomplished by twisting
> the blade midshaft, not rotating the entire blade in the hub.
>
> Also, with the auto engines the original poster is discussing, it is
> less a function of the engine and more a function of will the PSRU
> (re-drive) support a hydraulic governor. The Marcotte and Mistral PSRU's
> will support a hydraulic constant speed prop, others such as the Real
> World Solutions brand will not.
>
> An electric MT can be obtained that will run in the beta (and even
> reverse) ranges, but that is a $10k US proposition. Of course, getting a
> hydraulic governor, the price difference for a redrive that supports
> one, and getting a hydraulic CS prop, you are likely there with the cost
> of an Electric MT in the first place.
>
> It costs money.. plain and simple.
>
> The IVO may be an option for you, but as for a specific "beta" range, I
> am fairly sure it doesnt have one.
>
>
> Dave
>
> Gig 601XL Builder wrote:
>
>> I believe both the Woodcomp and the IVO will go into Beta.
>>
>>
>> "Rob Fonhof" > wrote in message
>> ...
>>
>>> Hi All.
>>> Just wondering if there are any props out there that can be used on
>>> an experimental aircraft engine, ie:subaru or RX-8 Renesis, which
>>> have a beta range. Don't even want to consider a certified unit as
>>> this would probably cost more than the rest of the firewall forward
>>> components.
>>> Thanks in advance,
>>> Rob.
>>> Melbourne Australia.
>>>
>>
>>
>>
>

"Dave S" > wrote in message
nk.net...
>I believe you are mistaken on the IVO.
>
> The IVO has a specific range of travel that is accomplished by twisting
> the blade midshaft, not rotating the entire blade in the hub.

I well could be plus in my head Beta means reversing. The reason for this is
when I was getting my helicopter rating the instructor used the term for
negative rotor pitch and it stuck in my head.

What would the point of this in a small plane be if not reversing?

I did find this definition for Beta.

Beta Control : A propeller which allows the manual repositioning of the
propeller blade angle beyond the normal low pitch stop. Used most often in
taxiing, where thrust is manually controlled by adjusting blade angle with
the power lever.

Gig 601XL Builder wrote:

> What would the point of this in a small plane be if not reversing?
>
>

My understanding is that the beta range is descriptive of the pitch
settings below "flight idle" in turboprop engines.

For instance, on a King Air, flight idle provides enough thrust to go 80
kts or something like that down the runway (or taxiway) (repeating
heresay, not speaking factually)..

Placing the props into the beta range allows selection of a ground idle
setting, that keeps the pilot from having to ride the brakes on the ground.

Selecting beta range (thrust below flight idle is how I am defining it)
in flight could result in too-rapid a descent.

In piston engines I suspect this is not as major of an issue, as you can
throttle the engine down to reduce power.

To repeat about the Ivo, based on your assumption that beta means
reversing.. the IVO does NOT reverse.

Dave

Gig 601XL Builder wrote:
> I well could be plus in my head Beta means reversing. The reason
for this is
> when I was getting my helicopter rating the instructor used the term for
> negative rotor pitch and it stuck in my head.
>
> What would the point of this in a small plane be if not reversing?

For a given beta pitch, the prop makes much more reverse thrust with
forward airspeed than when there is very little airspeed. This is
because of the angle of attack on the prop blades (aerodynamic
explanation using vectors).

The point is your landing rollout is greatly reduced, because the
prop provides a lot of deceleration immediately after touchdown when
the brakes are least effective (think, jam on the brakes too hard
when the wing is still making some lift, they lock up).

It's handy during taxiing when you can get no or slight reverse
thrust, that saves your brakes and is less workload when you get the
hang of it. It's usually a bad idea to reverse taxi- kick up fod
then roll through it as the engine ingests it, hard to see where
you're going, the nose (or tail) wheel may not castor 360 degrees...
to name a few reasons.

"Jim Carriere" > wrote

> It's handy (beta) during taxiing when you can get no or slight reverse
> thrust, that saves your brakes and is less workload when you get the
> hang of it. It's usually a bad idea to reverse taxi- kick up fod
> then roll through it as the engine ingests it, hard to see where
> you're going, the nose (or tail) wheel may not castor 360 degrees...
> to name a few reasons.

It is also -really- handy for seaplanes, who have *no* brakes. ;-))
--
Jim in NC

"Dave S" > wrote in message
nk.net...
> Gig 601XL Builder wrote:
>
>> What would the point of this in a small plane be if not reversing?
>>
>>
>
> My understanding is that the beta range is descriptive of the pitch
> settings below "flight idle" in turboprop engines.
>
> For instance, on a King Air, flight idle provides enough thrust to go 80
> kts or something like that down the runway (or taxiway) (repeating
> heresay, not speaking factually)..
>
> Placing the props into the beta range allows selection of a ground idle
> setting, that keeps the pilot from having to ride the brakes on the
> ground.
>
> Selecting beta range (thrust below flight idle is how I am defining it) in
> flight could result in too-rapid a descent.
>
> In piston engines I suspect this is not as major of an issue, as you can
> throttle the engine down to reduce power.
>
> To repeat about the Ivo, based on your assumption that beta means
> reversing.. the IVO does NOT reverse.
>


You were right. I looked at the WoodComp and the IVO at about the same time
a couple of months ago. The WoodComp does reverse.

I have a feeling the OP, like myself was confusing Beta with Reverse. So my
original answer to him was half right. ;)

Is it a good idea to have beta with any geared engines?

Aren't there typically problems with chattering the gears

back and forth leading to failures?



Mike

"Dave S" > wrote in message
nk.net...
>I believe you are mistaken on the IVO.
>
> The IVO has a specific range of travel that is accomplished by twisting
> the blade midshaft, not rotating the entire blade in the hub.
>
> Also, with the auto engines the original poster is discussing, it is less
> a function of the engine and more a function of will the PSRU (re-drive)
> support a hydraulic governor. The Marcotte and Mistral PSRU's will support
> a hydraulic constant speed prop, others such as the Real World Solutions
> brand will not.
>
> An electric MT can be obtained that will run in the beta (and even
> reverse) ranges, but that is a $10k US proposition. Of course, getting a
> hydraulic governor, the price difference for a redrive that supports one,
> and getting a hydraulic CS prop, you are likely there with the cost of an
> Electric MT in the first place.
>
> It costs money.. plain and simple.
>
> The IVO may be an option for you, but as for a specific "beta" range, I am
> fairly sure it doesnt have one.
>
>
> Dave
>
> Gig 601XL Builder wrote:
>> I believe both the Woodcomp and the IVO will go into Beta.
>>
>>
>> "Rob Fonhof" > wrote in message
>> ...
>>
>>>Hi All.
>>>Just wondering if there are any props out there that can be used on an
>>>experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a
>>>beta range. Don't even want to consider a certified unit as this would
>>>probably cost more than the rest of the firewall forward components.
>>>Thanks in advance,
>>>Rob.
>>>Melbourne Australia.
>>>
>>
>>
>>
>

Wouldn't you have this "effect" ANY time you went from a thrusting to a
braking action with regards to thrust generated?

If I pulled power back, set the pitch to flat, and pushed the nose over,
wouldn't the prop be "driving" the engine in the manner you describe?

All of this is able to be done without a specific Beta range.

Dave

PittsS1C wrote:
> Is it a good idea to have beta with any geared engines?
>
> Aren't there typically problems with chattering the gears
>
> back and forth leading to failures?
>
>
>
> Mike
>
> "Dave S" > wrote in message
> nk.net...
>
>>I believe you are mistaken on the IVO.
>>
>>The IVO has a specific range of travel that is accomplished by twisting
>>the blade midshaft, not rotating the entire blade in the hub.
>>
>>Also, with the auto engines the original poster is discussing, it is less
>>a function of the engine and more a function of will the PSRU (re-drive)
>>support a hydraulic governor. The Marcotte and Mistral PSRU's will support
>>a hydraulic constant speed prop, others such as the Real World Solutions
>>brand will not.
>>
>>An electric MT can be obtained that will run in the beta (and even
>>reverse) ranges, but that is a $10k US proposition. Of course, getting a
>>hydraulic governor, the price difference for a redrive that supports one,
>>and getting a hydraulic CS prop, you are likely there with the cost of an
>>Electric MT in the first place.
>>
>>It costs money.. plain and simple.
>>
>>The IVO may be an option for you, but as for a specific "beta" range, I am
>>fairly sure it doesnt have one.
>>
>>
>>Dave
>>
>>Gig 601XL Builder wrote:
>>
>>>I believe both the Woodcomp and the IVO will go into Beta.
>>>
>>>
>>>"Rob Fonhof" > wrote in message
...
>>>
>>>
>>>>Hi All.
>>>>Just wondering if there are any props out there that can be used on an
>>>>experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a
>>>>beta range. Don't even want to consider a certified unit as this would
>>>>probably cost more than the rest of the firewall forward components.
>>>>Thanks in advance,
>>>>Rob.
>>>>Melbourne Australia.
>>>>
>>>
>>>
>>>
>
>

I believe the porper operation of geard engines is not operate in regions of
zero thrust during glides (which is a common occurnace using beta during
taxi...)


Mike

"Dave S" > wrote in message
nk.net...
> Wouldn't you have this "effect" ANY time you went from a thrusting to a
> braking action with regards to thrust generated?
>
> If I pulled power back, set the pitch to flat, and pushed the nose over,
> wouldn't the prop be "driving" the engine in the manner you describe?
>
> All of this is able to be done without a specific Beta range.
>
> Dave
>
> PittsS1C wrote:
>> Is it a good idea to have beta with any geared engines?
>>
>> Aren't there typically problems with chattering the gears
>>
>> back and forth leading to failures?
>>
>>
>>
>> Mike
>>
>> "Dave S" > wrote in message
>> nk.net...
>>
>>>I believe you are mistaken on the IVO.
>>>
>>>The IVO has a specific range of travel that is accomplished by twisting
>>>the blade midshaft, not rotating the entire blade in the hub.
>>>
>>>Also, with the auto engines the original poster is discussing, it is less
>>>a function of the engine and more a function of will the PSRU (re-drive)
>>>support a hydraulic governor. The Marcotte and Mistral PSRU's will
>>>support a hydraulic constant speed prop, others such as the Real World
>>>Solutions brand will not.
>>>
>>>An electric MT can be obtained that will run in the beta (and even
>>>reverse) ranges, but that is a $10k US proposition. Of course, getting a
>>>hydraulic governor, the price difference for a redrive that supports one,
>>>and getting a hydraulic CS prop, you are likely there with the cost of an
>>>Electric MT in the first place.
>>>
>>>It costs money.. plain and simple.
>>>
>>>The IVO may be an option for you, but as for a specific "beta" range, I
>>>am fairly sure it doesnt have one.
>>>
>>>
>>>Dave
>>>
>>>Gig 601XL Builder wrote:
>>>
>>>>I believe both the Woodcomp and the IVO will go into Beta.
>>>>
>>>>
>>>>"Rob Fonhof" > wrote in message
...
>>>>
>>>>
>>>>>Hi All.
>>>>>Just wondering if there are any props out there that can be used on an
>>>>>experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a
>>>>>beta range. Don't even want to consider a certified unit as this would
>>>>>probably cost more than the rest of the firewall forward components.
>>>>>Thanks in advance,
>>>>>Rob.
>>>>>Melbourne Australia.
>>>>>
>>>>
>>>>
>>>>
>>
>>
>

I have forwarded this thread to the manufacturer of my redrive and to
the rotary engine discussion group to see if this concern has been borne
out in that engine type (that is one of the powerplants the OP was
inquiring about, as well as the powerplant that I am building now).

I am not contesting what you are claiming with regards to GO- series
engines, and operation at zero or less than zero net thrust in those
powerplants.

Dave

PittsS1C wrote:

> I believe the porper operation of geard engines is not operate in regions of
> zero thrust during glides (which is a common occurnace using beta during
> taxi...)
>
>
> Mike
>
> "Dave S" > wrote in message
> nk.net...
>
>>Wouldn't you have this "effect" ANY time you went from a thrusting to a
>>braking action with regards to thrust generated?
>>
>>If I pulled power back, set the pitch to flat, and pushed the nose over,
>>wouldn't the prop be "driving" the engine in the manner you describe?
>>
>>All of this is able to be done without a specific Beta range.
>>
>>Dave
>>
>>PittsS1C wrote:
>>
>>>Is it a good idea to have beta with any geared engines?
>>>
>>>Aren't there typically problems with chattering the gears
>>>
>>>back and forth leading to failures?
>>>
>>>
>>>
>>>Mike
>>>
>>>"Dave S" > wrote in message
nk.net...
>>>
>>>
>>>>I believe you are mistaken on the IVO.
>>>>
>>>>The IVO has a specific range of travel that is accomplished by twisting
>>>>the blade midshaft, not rotating the entire blade in the hub.
>>>>
>>>>Also, with the auto engines the original poster is discussing, it is less
>>>>a function of the engine and more a function of will the PSRU (re-drive)
>>>>support a hydraulic governor. The Marcotte and Mistral PSRU's will
>>>>support a hydraulic constant speed prop, others such as the Real World
>>>>Solutions brand will not.
>>>>
>>>>An electric MT can be obtained that will run in the beta (and even
>>>>reverse) ranges, but that is a $10k US proposition. Of course, getting a
>>>>hydraulic governor, the price difference for a redrive that supports one,
>>>>and getting a hydraulic CS prop, you are likely there with the cost of an
>>>>Electric MT in the first place.
>>>>
>>>>It costs money.. plain and simple.
>>>>
>>>>The IVO may be an option for you, but as for a specific "beta" range, I
>>>>am fairly sure it doesnt have one.
>>>>
>>>>
>>>>Dave
>>>>
>>>>Gig 601XL Builder wrote:
>>>>
>>>>
>>>>>I believe both the Woodcomp and the IVO will go into Beta.
>>>>>
>>>>>
>>>>>"Rob Fonhof" > wrote in message
...
>>>>>
>>>>>
>>>>>
>>>>>>Hi All.
>>>>>>Just wondering if there are any props out there that can be used on an
>>>>>>experimental aircraft engine, ie:subaru or RX-8 Renesis, which have a
>>>>>>beta range. Don't even want to consider a certified unit as this would
>>>>>>probably cost more than the rest of the firewall forward components.
>>>>>>Thanks in advance,
>>>>>>Rob.
>>>>>>Melbourne Australia.
>>>>>>
>>>>>
>>>>>
>>>>>
>>>
>
>

"Dave S" > wrote in message
nk.net...
> Wouldn't you have this "effect" ANY time you went from a thrusting to a
> braking action with regards to thrust generated?
>
> If I pulled power back, set the pitch to flat, and pushed the nose over,
> wouldn't the prop be "driving" the engine in the manner you describe?
>
> All of this is able to be done without a specific Beta range.
>
> Dave

Actually, no. Kinda. <g>

When the engine is using HP to turn the prop, all is well, be it forward or
reverse thrust. The only difference the gearing sees is the thrust on the
shaft goes from pulling the shaft out, to pushing the shaft in, but the load
on the gears is the same. (all for tractor applications, in this case)

When the possible chattering comes in, is when you are gliding, and at a
very low power setting, and the *windmilling* prop is trying to turn the
engine, thus the prop is "making" HP to try to turn the engine- opposite
from normal.
--
Jim in NC

And after discussing it with the rotary engine gang, the consensus is..
that you pass through this area of "chatter" fairly quickly.. either you
are engine driving prop.. or prop driving engine... but from a practical
matter you are not loitering in the power/thrust range that is teetering
between the two.

Every geared engine passes through this range several times on a given
flight, but rarely loiters there.

Even in ground ops.. you are pushing.. or pulling.. but rarely
straddling the fence.

Dave

Morgans wrote:
> "Dave S" > wrote in message
> nk.net...
>
>>Wouldn't you have this "effect" ANY time you went from a thrusting to a
>>braking action with regards to thrust generated?
>>
>>If I pulled power back, set the pitch to flat, and pushed the nose over,
>>wouldn't the prop be "driving" the engine in the manner you describe?
>>
>>All of this is able to be done without a specific Beta range.
>>
>>Dave
>
>
> Actually, no. Kinda. <g>
>
> When the engine is using HP to turn the prop, all is well, be it forward or
> reverse thrust. The only difference the gearing sees is the thrust on the
> shaft goes from pulling the shaft out, to pushing the shaft in, but the load
> on the gears is the same. (all for tractor applications, in this case)
>
> When the possible chattering comes in, is when you are gliding, and at a
> very low power setting, and the *windmilling* prop is trying to turn the
> engine, thus the prop is "making" HP to try to turn the engine- opposite
> from normal.

I guess my point was that, whenever I have been with someone using beta,
they spent lots of time loitering there.
Positive thrust to get moving then hanging out in the zero thrust area with
little adjustments positive and negative during taxi.
I think I would hesitate to use a geared engine for taxing that way (like
turbine planes do)


"Dave S" > wrote in message
nk.net...
> And after discussing it with the rotary engine gang, the consensus is..
> that you pass through this area of "chatter" fairly quickly.. either you
> are engine driving prop.. or prop driving engine... but from a practical
> matter you are not loitering in the power/thrust range that is teetering
> between the two.
>
> Every geared engine passes through this range several times on a given
> flight, but rarely loiters there.
>
> Even in ground ops.. you are pushing.. or pulling.. but rarely straddling
> the fence.
>
> Dave
>
> Morgans wrote:
>> "Dave S" > wrote in message
>> nk.net...
>>
>>>Wouldn't you have this "effect" ANY time you went from a thrusting to a
>>>braking action with regards to thrust generated?
>>>
>>>If I pulled power back, set the pitch to flat, and pushed the nose over,
>>>wouldn't the prop be "driving" the engine in the manner you describe?
>>>
>>>All of this is able to be done without a specific Beta range.
>>>
>>>Dave
>>
>>
>> Actually, no. Kinda. <g>
>>
>> When the engine is using HP to turn the prop, all is well, be it forward
>> or
>> reverse thrust. The only difference the gearing sees is the thrust on
>> the
>> shaft goes from pulling the shaft out, to pushing the shaft in, but the
>> load
>> on the gears is the same. (all for tractor applications, in this case)
>>
>> When the possible chattering comes in, is when you are gliding, and at a
>> very low power setting, and the *windmilling* prop is trying to turn the
>> engine, thus the prop is "making" HP to try to turn the engine- opposite
>> from normal.
>

On Wed, 10 Aug 2005 00:57:18 -0400, Morgans wrote:

>
> "Jim Carriere" > wrote
>
>> It's handy (beta) during taxiing when you can get no or slight reverse
>> thrust, that saves your brakes and is less workload when you get the
>> hang of it. It's usually a bad idea to reverse taxi- kick up fod then
>> roll through it as the engine ingests it, hard to see where you're
>> going, the nose (or tail) wheel may not castor 360 degrees... to name a
>> few reasons.
>
> It is also -really- handy for seaplanes, who have *no* brakes. ;-))


But, having a prop with a beta or reverse capability adds new very nasty
failure modes. Type certificated aircraft with props that have a beta or
reverse functionality have additional complicated monitors to prevent the
prop from going into uncommanded beta or reverse in flight. I would want
a prop with the low pitch stop set to a position that is safe for
in-flight operation. If the prop goes into beta or reverse in the air it
can kill you.

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com

"Dave S" > wrote

> And after discussing it with the rotary engine gang, the consensus is..
> that you pass through this area of "chatter" fairly quickly.. either you
> are engine driving prop.. or prop driving engine... but from a practical
> matter you are not loitering in the power/thrust range that is teetering
> between the two.

All very true. You get pressure of the opposite side of the gears from
normal, but it would indeed be rare for it to get to the RPM where it is so
closely balanced, as to go from one to the other, rapidly.

All of this is reason to make the gears tight fitting, with little lash.
More lash gives time for the motion to set up with a "head start", providing
more force to break things. Broken things = bad. <g>
--
Jim in NC
--
Jim in NC

"PittsS1C" > wrote

> Positive thrust to get moving then hanging out in the zero thrust area
with
> little adjustments positive and negative during taxi.
> I think I would hesitate to use a geared engine for taxing that way (like
> turbine planes do)

I can't say with 100% authority, but I don't see that as a problem. Just
because there is zero thrust, does not mean the engine/gearbox has zero
load. Even at beta, the prop is still moving a lot of air, but off of the
front and the back and ends of the prop, at the same time. Considerable HP
is still being used, and putting a constant, normal load on the gears.

Think of a "club" prop, for breaking in engines, or using on a "torque" type
dyno. It is indeed putting a load on the engine and gearbox, but it is not
trying to make thrust, so the test stand/dyno doesn't zoom down the length
of the driveway. <g>
--
Jim in NC