Beta Prop

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 the

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.