Today's Message Index:
----------------------
1. 11:12 AM - Re: PV-50 Prop settings (Steve Ivell)
2. 11:43 AM - Re: PV-50 Prop settings (D McFadyean)
3. 08:41 PM - Re: PV-50 Prop settings (Area-51)
4. 08:42 PM - Re: PV-50 Prop settings (Area-51)
Message 1
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| Subject: | PV-50 Prop settings |
Hi Pete
In the UK the Rotax912/4 is used a lot in microlights and they tend to be f
lown at much lower revs.... somewhere between 4000 and 4500....and I don't
hear of loads of gearbox problems.
Because of noise certificates many Rotax micros are set up to max static of
4800.
Go figure??
Kind Regards
Steve Ivell
GSTES
E-mail: steveivell@pestproof.co.uk<mailto:steveivell@pestproof.co.uk>
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of Pete Zut
Sent: 24 March 2022 15:36
Subject: Re: Europa-List: PV-50 Prop settings
Can't advisde on the adjustment to get more fine, but opening a can of worm
s: Isn't 4700rpm cruise brutal on the gearbox? How many hours do you have
on the box now, and have you had a 600hr service, and if yes, what were th
e observations? The advice by my local cert'd rotax guys is to always crui
se above 5100rpm.
Are many others cruising that low? .... and how are their gearbox's holding
up?
Cheers and thx,
PeteZ
C-GNPZ
On Thu, Mar 24, 2022 at 11:09 AM Paul Hawkins <pwhawkinsbuilders@hotmail.co
m<mailto:pwhawkinsbuilders@hotmail.com>> wrote:
Hi
Some advice please on prop settings, my Europa has a 914 engine with an Arp
last PV-50 prop in fine pitch it=92s set to give just under 5400 rpm static
and on take-off works as it should the problem is when I set to cruise I a
im for 130 Kts but I have to keep coming back on the throttle not to go abo
ve that speed I end up with 130 Kts with an rpm of 4200 the problem started
after a prop service, normally I tend to cruise at 125/130 for 4650/4700 r
pm-ish, there=92s 10=B0 difference between fine and coarse pitch, which way
should I adjust + or ' the 10=B0 prop difference?
Cheers Paul
Message 2
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| Subject: | PV-50 Prop settings |
And in (training) microlight aircraft it's not unheard that the 912 will go
to 3000+ hours.
Duncan McF.
> On 25 March 2022 at 18:12 Steve Ivell <SteveIvell@pestproof.co.uk> wrote:
>
>
>
> Hi Pete
>
>
>
> In the UK the Rotax912/4 is used a lot in microlights and they tend t
o be flown at much lower revs.... somewhere between 4000 and 4500....and I
don't hear of loads of gearbox problems.
>
> Because of noise certificates many Rotax micros are set up to max sta
tic of 4800.
>
> Go figure??
>
>
>
> Kind Regards
>
>
>
> Steve Ivell
>
> GSTES
>
> E-mail: steveivell@pestproof.co.uk mailto:steveivell@pestproof.co.uk
>
>
>
> From: owner-europa-list-server@matronics.com <owner-europa-list-serve
r@matronics.com> On Behalf Of Pete Zut
> Sent: 24 March 2022 15:36
> To: europa-list <europa-list@matronics.com>
> Subject: Re: Europa-List: PV-50 Prop settings
>
>
>
> Can't advisde on the adjustment to get more fine, but opening a can o
f worms: Isn't 4700rpm cruise brutal on the gearbox? How many hours do yo
u have on the box now, and have you had a 600hr service, and if yes, what w
ere the observations? The advice by my local cert'd rotax guys is to alway
s cruise above 5100rpm.
>
>
>
> Are many others cruising that low? .... and how are their gearbox's h
olding up?
>
>
>
> Cheers and thx,
>
> PeteZ
>
> C-GNPZ
>
>
>
> On Thu, Mar 24, 2022 at 11:09 AM Paul Hawkins <pwhawkinsbuilders@hotm
ail.com mailto:pwhawkinsbuilders@hotmail.com > wrote:
>
> > >
> >
> >
> >
> >
> > Hi
> >
> >
> >
> > Some advice please on prop settings, my Europa has a 914 engine
with an Arplast PV-50 prop in fine pitch it=99s set to give just und
er 5400 rpm static and on take-off works as it should the problem is when I
set to cruise I aim for 130 Kts but I have to keep coming back on the thro
ttle not to go above that speed I end up with 130 Kts with an rpm of 4200 t
he problem started after a prop service, normally I tend to cruise at 125/1
30 for 4650/4700 rpm-ish, there=99s 10=C2=B0 difference between fine
and coarse pitch, which way should I adjust + or =93 the 10=C2=B0 pro
p difference?
> >
> >
> >
> > Cheers Paul
> >
> >
> >
> >
> >
> > >
Message 3
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| Subject: | Re: PV-50 Prop settings |
I'm not afraid to open pandora boxes; I agree with Rotax recommendations to cruise
at 5000rpm or above and set the idle not below 2000rpm. Why? Because these
power plants have a TBO rating that allows them to perform their intended task
all the way up to the full allocated time at a price point that allows replacement
at half life, if you on-sell the used unit, or replacement at zero TBO,
i.e run it at full power and then throw away the unit... it will last the entire
TBO without failure; and that is all it needs to do as far as the factory
is concerned.... if i was a manufacturer with a business plan thats how i would
do it as well; and would be thrilled to supply a brand new fresh unit every
1600 or 2000 hours of use.
Reasons why I believe the 80hp 912UL can be cruised under 5000rpm; it has a different
valve timing profile and flatter torque curve than the ULS; reasons I believe
the 912 idle speed can be lowered to 1600rpm; new style composite foam
core props are extremely low mass and do not allow the spur gears in the gearbox
to chatter as would be the case with heavier solid blades; if you can hear
the gearbox chattering at idle then the idle speed is too low... why I believe
cruising at under 5000rpm has no affect on gearbox life; the propeller is under
constant load in cruise regardless of rpm; how are the spur gears going to
chatter and wear out prematurely if they are operating at constant load? Why mechanical
parts fail; material failure due to physical impact, friction heat,
and sustained harmonic resonance leading to disruption of atomic attachment. The
last reason possibly being why rotax recommends the operational rpm they do...
however the physical proof of powerplants continuing to operate under condition
well past their TBO times causes me to doubt this.
Nail a VW beetle engine to a powerpole and run it at WOT see how long it runs continuously...
nail another one to the same pole and run it at 75% power see how
long it runs for continuously... minus the lower time from the higher time
and divide the answer by the length and thickness of the said pole... perform
the same two tests repeatedly with a variety of different length and thickness
poles to ascertain which length and thickness pole offers the longest lasting
engine running time before failure of either the pole or the engine... if dimensions
of pole dimensions fail to affect service life of either test unit then
it can be ascertained that the pole is not a mitigating factor and it is inconclusively
perhaps the rom range chosen for each test performed.
I have an 80hp ULS in my 325kg mono with 310hrs on it since bulk strip overhaul...
it cruises all day long unstressed @100kt IAS @ 4700rpm with a 3 blade 64"
Bolly prop set at 19deg pitch and 12lph fuel burn rate... with the idle set at
2000rpm over the fence I'm remaining within ground affect for the entire length
of the field at roundout; at 1600rpm I am on the ground where I intend to
be, and on the ramp my gearbox is not chattering... guaranteed when this powerplant
reaches its TBO's it will still be well within rotax wear limitations for
continued service life on condition.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=506402#506402
Message 4
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| Subject: | Re: PV-50 Prop settings |
I'm not afraid to open pandora boxes; I agree with Rotax recommendations to cruise
at 5000rpm or above and set the idle not below 2000rpm. Why? Because these
power plants have a TBO rating that allows them to perform their intended task
all the way up to the full allocated time at a price point that allows replacement
at half life, if you on-sell the used unit, or replacement at zero TBO,
i.e run it at full power and then throw away the unit... it will last the entire
TBO without failure; and that is all it needs to do as far as the factory
is concerned.... if i was a manufacturer with a business plan thats how i would
do it as well; and would be thrilled to supply a brand new fresh unit every
1600 or 2000 hours of use.
Reasons why I believe the 80hp 912UL can be cruised under 5000rpm; it has a different
valve timing profile and flatter torque curve than the ULS; reasons I believe
the 912 idle speed can be lowered to 1600rpm; new style composite foam
core props are extremely low mass and do not allow the spur gears in the gearbox
to chatter as would be the case with heavier solid blades; if you can hear
the gearbox chattering at idle then the idle speed is too low... why I believe
cruising at under 5000rpm has no affect on gearbox life; the propeller is under
constant load in cruise regardless of rpm; how are the spur gears going to
chatter and wear out prematurely if they are operating at constant load? Why mechanical
parts fail; material failure due to physical impact, friction heat,
and sustained harmonic resonance leading to disruption of atomic attachment. The
last reason possibly being why rotax recommends the operational rpm they do...
however the physical proof of powerplants continuing to operate under condition
well past their TBO times causes me to doubt this.
Nail a VW beetle engine to a powerpole and run it at WOT see how long it runs continuously...
nail another one to the same pole and run it at 75% power see how
long it runs for continuously... minus the lower time from the higher time
and divide the answer by the length and thickness of the said pole... perform
the same two tests repeatedly with a variety of different length and thickness
poles to ascertain which length and thickness pole offers the longest lasting
engine running time before failure of either the pole or the engine... if dimensions
of pole dimensions fail to affect service life of either test unit then
it can be ascertained that the pole is not a mitigating factor and it is inconclusively
perhaps the rom range chosen for each test performed.
I have an 80hp ULS in my 325kg mono with 310hrs on it since bulk strip overhaul...
it cruises all day long unstressed @100kt IAS @ 4700rpm with a 3 blade 64"
Bolly prop set at 19deg pitch and 12lph fuel burn rate... with the idle set at
2000rpm over the fence I'm remaining within ground affect for the entire length
of the field at roundout; at 1600rpm I am on the ground where I intend to
be, and on the ramp my gearbox is not chattering... guaranteed when this powerplant
reaches its TBO's it will still be well within rotax wear limitations for
continued service life on condition.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=506403#506403
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