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E-Props ...who has first hand experience with these


eightyknots

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cant compare unless airspeed /efficiency is in the picture.

I went four blade for rotax because of superior takeoff performance- more blades, less blade loading per blade and not as far into 'stall' if you like , IE AoA per blade lower , ---at low airspeeds much less than the screw speed.  Exact performance will depend a bit at what drag you end up with and IE what RPM your end up with.  Little / no penalty for 4 versus 2 blades with the Eprop at cruise speed. That's the advantage I like. AND Eprop will get you all this data...

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You tend to have a fascination with the complex. Our planes don't cruise that fast. There used t5o be rules of thumb that covered all the prop angle settings and Jabiru don't like  being overpropped.  Nev

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  • 4 months later...

Ok,  We're finally flying with our Just Aircraft Highlander with a Rotax 912is Sport engine and the 3 blade ground adjustable Durandal eProp.  We're currently seeing  5450-5500 RPM at WOT level cruise (Alt 3000ft and MAP is 26.5 inHg) and 5000-5050 RPM in sustained climbs.  This seems to be where eProps wants the WOT level flight RPM.  Should we decrease the prop to get our climb RPM up a little higher?  We realize we'll hurt our top end cruise speed and improve our climb performance.  We're also trying to balance the 912is engine with it's Power/ECO modes.  

 

What is everyone's thoughts here?

 

==

Michael Crowder

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We supply a 2-blade propeller with a diameter of 2 m (78.7") on this airplane and motor. With more powerful motors, 3 and 4 blade versions of the same diameter. Would be curious to compare :).

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For something like the rotax , for a prop pitched for max rpm at best climb, we  control climb RPM at WOT by pitching up the aircraft and slowing the aircraft down and prop RPM falls  to within limits.      Generally we do not fly at WOT  when S&L , this would mean an overspeed.

 

If you operate out of restricted ALAs, I would be pitching it for MAX RPM (5800) at  best climb . That is what matters most when you need to clear the trees.   You could also pitch for 5800 at  best angle (usually slower) but  might mean you overspeed at 75% cruise in S&L but that will depend on the airframe (drag behaviour)  and the prop . IE how much faster cruise is. 

If you pitch for 5500 RPM at 75% S&L, you might be leaving some climb performance on the table , that depends on  the difference between best climb and your 75% cruise speed. If there is not much of a difference, then pitching for best angle might still mean you dont overspeed at 75% S&L. 

 

BUT Different props will have different airspeed behaviour.

 

Edited by RFguy
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And also consider an airplane pitched for a student might be different to for a seasoned pilot. That is to say, maybe do not pitch the prop too fine such that the student is having to continuously be concerned with the engine overspeeding when the primary objective is to learn to fly the aircraft. IE might be pitched for 5500 WOT best climb to give the student some breathing space (but leaves some performance on the table) 

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Read the instructions for Eprop..they are the designers and manufacturers..they say pitch for 5500 WOT in level flight. This is where the prop is most efficient

Setting it anywhere else you will obviously compromise the original design critieria. That drop off seems to be pretty large from my experience here with over 50 Eprop propellors fitted you must have a very high AOA on takeoff. most will climb at around 5200 to 5300 rpm when set to 5500 at WOT

 

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15 hours ago, meglin said:

We supply a 2-blade propeller with a diameter of 2 m (78.7") on this airplane and motor. With more powerful motors, 3 and 4 blade versions of the same diameter. Would be curious to compare :).

what would you supply for an xair standard with a 582 and 2.62 -1 gearbox.

i got a quote on an e prop but that was far too expensive with our poor exchange rate.

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Of course, the 3-blade propeller is 1700 mm (67") in diameter. It can be saber blades (quieter) or classic blades (cheaper).

If clearance allows, you can also go with 2 blades of 68,9". There can be saber, classic and ellipse-shaped blades.

There is no point in talking about price - it is always lower than quality. 

L-83---.jpg

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2 hours ago, meglin said:

Of course, the 3-blade propeller is 1700 mm (67") in diameter. It can be saber blades (quieter) or classic blades (cheaper).

If clearance allows, you can also go with 2 blades of 68,9". There can be saber, classic and ellipse-shaped blades.

There is no point in talking about price - it is always lower than quality. 

L-83---.jpg

Nice looking prop 

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1 hour ago, Kyle Communications said:

EXC-3-185-C4-T (X-AIR Rotax 582 gear ratio 2.62)

 

This is what you would require for your Xair

 

Yes. I had the model number from e props website which is excellent by the way.  But $4500 with spinner compared to $1900 for a bolly. I think we're below 60 cents exchange rate the day I got the quote.

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Got a response from Anne LAVRAND President / Sales Manager at eProps.  They think the prop is tuned where's it needs to be.  She even indicated that the WT9 with 912iS only gets 4800 on climb out and has been blessed by Rotax.

 

Thanks everyone for the advice.

 

Michael

 

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  • 1 month later...
  • 4 weeks later...
  • 2 months later...
On 19/09/2023 at 7:19 AM, Kyle Communications said:

Read the instructions for Eprop..they are the designers and manufacturers..they say pitch for 5500 WOT in level flight. This is where the prop is most efficient

Setting it anywhere else you will obviously compromise the original design critieria. That drop off seems to be pretty large from my experience here with over 50 Eprop propellors fitted you must have a very high AOA on takeoff. most will climb at around 5200 to 5300 rpm when set to 5500 at WOT

 

The props are designed for 5,500rpm  (the November video is very misleading for other than STOL comp performance with its 6,000rpm talk as I set mine for 5,800 and performance dropped 10 - 12 knots; could not make 100 kts  at WOT S&L where as the 5,500 rpm setting would make 108 kts)  I don't understand why this is so as I thought the 5,800 Take off rpm would be the 98hp and 5,500 rpm is about 90 hp.  Have today reset pitch for 5,500 rpm so will fly tomorrow and should be back to where it was.   

 

The reason I set the rpm first was mainly due to always aiming for 5,500 to 5,600 rpm WOT S&L.  The manual for E-Props said 5,500 rpm best and also said to set prop for 5,100 to 5,800 rpm static.  This lead me to try it at 5,800 rpm.  Big FAIL result; so just set for 5,500 rpm and leave there.  110% happy with the E-Prop and great value for money and good for 4,000 hours.  Posted to share my experience; Cheers.

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Mike I would have thought you would have seen the guys that put it at 5800..that is for IFA props NOT ground adjustable. Eprop also have specifically designed their props to work on Rotax engines with gearboxes and also their slightly different ratios. I cant seem to convince the old guys that 5800 is NOT where you should place any ground adjustable prop on a Rotax with a gearbox. Just think about it. Yes it maybe a little better at takeoff with the fine pitch but as soon as you want cruise if you set the pitch to 5800 at WOT then when you bring it back to cruise you will NOT have the same thrust at `5000 rpm as when you set your WOT to 5500 rpm...that is just mother nature.

That video of Jonas is specific to stol takeoff and short straight around circuit...NOTHING else..its a specific thing. I think he does mention something about it. 

 

I have had a few customers who did not listen to me and set the props at 5800 because the guru at the airfield said this is how you do it. You listen to the designers of the prop.

 

 

Mark

 

 

 

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3 minutes ago, Kyle Communications said:

Mike I would have thought you would have seen the guys that put it at 5800..that is for IFA props NOT ground adjustable. Eprop also have specifically designed their props to work on Rotax engines with gearboxes and also their slightly different ratios. I cant seem to convince the old guys that 5800 is NOT where you should place any ground adjustable prop on a Rotax with a gearbox. Just think about it. Yes it maybe a little better at takeoff with the fine pitch but as soon as you want cruise if you set the pitch to 5800 at WOT then when you bring it back to cruise you will NOT have the same thrust at `5000 rpm as when you set your WOT to 5500 rpm...that is just mother nature.

That video of Jonas is specific to stol takeoff and short straight around circuit...NOTHING else..its a specific thing. I think he does mention something about it. 

 

I have had a few customers who did not listen to me and set the props at 5800 because the guru at the airfield said this is how you do it. You listen to the designers of the prop.

 

 

Mark

 

 

 

Thanks Mark; no have not been looking at any constant speed IFA prop videos.  I'll have a look in a few days as keen to see effect of pitch change to coarser but for me can only relate to performance on a Nynja.  If E=Props have a specific Nynja IFA review I'd be keen to view.  Not ever looking at a glorious prop at this stage very happy with ground adjustable.  Spoke to Neil up here and will assist him with his prop on the Bristelle he has the paper work and mass weight for his plane now just needs some bolts for it.  Cheers.

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Make sure he sets WOT at 5500. A manual IFA would be great i think but Eprop only do the Glorieus which is hydraulic with a controller. Realistically for our sort of high wing aircraft its a expensive option for not a huge difference. If you had a fast machine like a Blackshape well then yes you will get a super top end speed but our aircraft have too much drag

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Hi Kyle,

 

Three questions:

  • Is there a CS (Glorious) E-prop in Australia?
  • Why have E-Prop opted for hydraulic pitch change, rather than one of the electric systems?
  • Is there an In-Flight-Adjustable variant of the Glorious (or plans to offer one)?
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yes there is although its on a Kitfox not a speed machine. This is the only one I know of 

 

They have a hydraulic module they think its better than electric but they do have a config 3 version that is electric

 

They have a manual version coming but it is for the 912 IS and the 915 IS...i think because the hole in the gearbox maybe different

 

https://aircraft.e-props.fr/GL_CS/#tit04

 

 

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