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PV-50 Prop settings

 
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Paul Hawkins



Joined: 05 Jun 2011
Posts: 5
Location: BIGGIN HILL UK

PostPosted: Thu Mar 24, 2022 7:00 am    Post subject: PV-50 Prop settings Reply with quote

Hi

Some advice please on prop settings, my Europa has a 914 engine with an Arplast PV-50 prop in fine pitch it’s 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 aim for 130 Kts but I have to keep coming back on the throttle not to go above 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 rpm-ish, there’s 10° difference between fine and coarse pitch, which way should I adjust + or – the 10° prop difference?

Cheers Paul


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peterz(at)zutrasoft.com
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PostPosted: Thu Mar 24, 2022 7:36 am    Post subject: PV-50 Prop settings Reply with quote

Can't advisde on the adjustment to get more fine, but opening a can of worms:  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 the observations?  The advice by my local cert'd rotax guys is to always cruise 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(at)hotmail.com (pwhawkinsbuilders(at)hotmail.com)> wrote:

Quote:

 
 
Hi
 
Some advice please on prop settings, my Europa has a 914 engine with an Arplast PV-50 prop in fine pitch it’s 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 aim for 130 Kts but I have to keep coming back on the throttle not to go above 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 rpm-ish, there’s 10° difference between fine and coarse pitch, which way should I adjust + or – the 10° prop difference?
 
Cheers Paul
 
 



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ward.t(at)xtra.co.nz
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PostPosted: Thu Mar 24, 2022 10:44 am    Post subject: PV-50 Prop settings Reply with quote

Pete,Airmaster CSU sets the cruise rpm at 5000rpm as recommended in Rotax POH.
You can of course adjust it as required with the CSU. I use 4500rpm in the circuit when giving other pilots a rating. Otherwise the speed downwind increases to 125kts only having to reduce it to 83kts for gear extension.
Gear box torque on last annual check was good. 850hrs.
Cheers,
Tim

Sent from my iPadTim Ward
12 Waiwetu Street,
Fendalton,
Christchurch, 8052
New Zealand.
ward.t(at)xtra.co.nz
021 0640221
Quote:
On 25/03/2022, at 4:44 AM, Pete Zut <peterz(at)zutrasoft.com> wrote:

Can't advisde on the adjustment to get more fine, but opening a can of worms: 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 the observations?  The advice by my local cert'd rotax guys is to always cruise 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(at)hotmail.com (pwhawkinsbuilders(at)hotmail.com)> wrote:

Quote:



Hi

Some advice please on prop settings, my Europa has a 914 engine with an Arplast PV-50 prop in fine pitch it’s 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 aim for 130 Kts but I have to keep coming back on the throttle not to go above 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 rpm-ish, there’s 10° difference between fine and coarse pitch, which way should I adjust + or – the 10° prop difference?

Cheers Paul







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SteveIvell(at)pestproof.c
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PostPosted: Fri Mar 25, 2022 10:12 am    Post subject: PV-50 Prop settings Reply with quote

Hi Pete

In the UK the Rotax912/4 is used a lot in microlights and they tend to 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 static of 4800.
Go figure??

Kind Regards
 
Steve Ivell
GSTES
E-mail: steveivell(at)pestproof.co.uk (steveivell(at)pestproof.co.uk)

From: owner-europa-list-server(at)matronics.com <owner-europa-list-server(at)matronics.com> On Behalf Of Pete Zut
Sent: 24 March 2022 15:36
To: europa-list <europa-list(at)matronics.com>
Subject: Re: PV-50 Prop settings


Can't advisde on the adjustment to get more fine, but opening a can of worms: 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 the observations? The advice by my local cert'd rotax guys is to always cruise 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(at)hotmail.com (pwhawkinsbuilders(at)hotmail.com)> wrote:
Quote:



Hi

Some advice please on prop settings, my Europa has a 914 engine with an Arplast PV-50 prop in fine pitch it’s 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 aim for 130 Kts but I have to keep coming back on the throttle not to go above 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 rpm-ish, there’s 10° difference between fine and coarse pitch, which way should I adjust + or – the 10° prop difference?

Cheers Paul





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Duncan McFadyean



Joined: 18 Jan 2011
Posts: 218

PostPosted: Fri Mar 25, 2022 10:43 am    Post subject: PV-50 Prop settings Reply with quote

And in (training) microlight aircraft it's not unheard that the 912 will go to 3000+ hours.


Duncan McF.
Quote:
On 25 March 2022 at 18:12 Steve Ivell <SteveIvell(at)pestproof.co.uk> wrote:




Hi Pete

In the UK the Rotax912/4 is used a lot in microlights and they tend to 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 static of 4800.
Go figure??

Kind Regards

Steve Ivell
GSTES
E-mail: steveivell(at)pestproof.co.uk (steveivell(at)pestproof.co.uk)

From: owner-europa-list-server(at)matronics.com <owner-europa-list-server(at)matronics.com> On Behalf Of Pete Zut
Sent: 24 March 2022 15:36
To: europa-list <europa-list(at)matronics.com>
Subject: Re: Europa-List: PV-50 Prop settings


Can't advisde on the adjustment to get more fine, but opening a can of worms: 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 the observations? The advice by my local cert'd rotax guys is to always cruise 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(at)hotmail.com (pwhawkinsbuilders(at)hotmail.com)> wrote:
Quote:



Hi

Some advice please on prop settings, my Europa has a 914 engine with an Arplast PV-50 prop in fine pitch it’s 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 aim for 130 Kts but I have to keep coming back on the throttle not to go above 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 rpm-ish, there’s 10° difference between fine and coarse pitch, which way should I adjust + or – the 10° prop difference?

Cheers Paul







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Area-51



Joined: 03 May 2021
Posts: 371

PostPosted: Fri Mar 25, 2022 7:40 pm    Post subject: Re: PV-50 Prop settings Reply with quote

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 being the end result of all causal affects. The last reason, harmonic resonance, 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 to assume perhaps the rpm range chosen for each test performed is the contributing factor to times before failure of each test unit.

I have an 80hp ULS in my 325kg mono with 310hrs on it since bulk strip overhaul... it cruises all day long unstressed (at)100kt IAS (at) 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.


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n7188u



Joined: 15 Nov 2015
Posts: 395

PostPosted: Mon Mar 28, 2022 9:42 am    Post subject: Re: PV-50 Prop settings Reply with quote

My 2 cents regarding low rpm operation:

I have found that my mono, with a fixed pitch DUC prop, is a fun airplane when happily cruising at over 5000 rpm (generally at 5200) at altitude and no turbulence.

But when doing local hops at low altitude and a little turbulence it is no fun at all since at anything near 5000 rpm it’s is over 130 kias and it’s a harsh ride.

So I made the decision to enjoy the plane and just throttle back to anything between 4600 to 4900 rpm depending what my spine tolerates. I just feel for any spot where there is an increase in vibration and stay out of it. If the gearbox will need work in the future so be it.

On x-country trips though I am higher and have proper cruise rpm.

Is this good or bad I dunno. I was told that it’s not an issue. Time will tell but for now I am prioritizing enjoyment.

I will however take a little pitch of the prop to improve initial climb when heavy and warm but not much. Not really willing to give up that nice 135 knot cruise my little rocket gives me now Smile

Best Regards,
Chris


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