DJ Todd B Posted May 30 Report Share Posted May 30 Just looking to see what the E-Prop owners out there have set their pitch to and was it for more Climb or Cruise. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted May 30 Report Share Posted May 30 10 hours ago, DJ Todd B said: Just looking to see what the E-Prop owners out there have set their pitch to and was it for more Climb or Cruise. A properly set E-Prop will improve both climb and cruise over a Neuform. Pitch it to be ~5500rpm at WOT in cruise at a typical cruise altitude for you. Do a search on these forums and you should find some people posting their pitch numbers. IIRC the typical pitch ends up somewhere around 27-27.5°. Be aware that the E-prop acts a little backwards compared to other props. Most other props on a takeoff run load up and and have a slower RPM that increases as you pick up speed. The E-prop is reversed, it starts out at higher rpm and then the rpm comes down as you accelerate. My RPM is about 5700 when I first go to full power, then slows to about 5300-5400 in the steepest part of the climb, and finally creeps back up to 5500 (at WOT) once leveled out in cruise. Talking to E-props folks I gather this behavior is because the shape and twist of the blades causes different parts along the length of the blade to be more or less efficient at different loadings and blade AoA, giving what they call their "constant speed effect". Quote Link to comment Share on other sites More sharing options...
Madhatter Posted May 30 Report Share Posted May 30 5500 rpm is optimal. Anything above or below reduces performance, I have experimented with this prior to the prop being approved in the US for FD and approval was based on the data. I am hoping to do the same for the Jabiru 230. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted May 30 Report Share Posted May 30 9 minutes ago, Madhatter said: 5500 rpm is optimal. Anything above or below reduces performance, I have experimented with this prior to the prop being approved in the US for FD and approval was based on the data. I agree. Am I remembering right that that's usually around 27° blade pitch? Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted May 31 Report Share Posted May 31 9 hours ago, FlyingMonkey said: I agree. Am I remembering right that that's usually around 27° blade pitch? My last repitch was around 26 degress, but that was using the less than accurate e-props level. 11 hours ago, FlyingMonkey said: Pitch it to be ~5500rpm at WOT in cruise at a typical cruise altitude for you The latest manual now states 5500 rpm WOT at 2500 feet MSL. I ended up having to increase the pitch slightly to get that. I was at around 25.5 before that and had to increase to 26 after I saw that in the revised install manual. I originally set it for 5500 RPM at 5500 feet which is my average/normal cruise altitude. Don't think it'll make that much of a difference though, as I didn't really even notice a change overall. Quote Link to comment Share on other sites More sharing options...
shiny.ice Posted May 31 Report Share Posted May 31 my newly installed e-prop is 26.something, using the 2500ft MSL metric I'm just a touch low (5450rpm or so). I've put 14 hours on it. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted May 31 Report Share Posted May 31 11 hours ago, Garrett Gee said: My last repitch was around 26 degress, but that was using the less than accurate e-props level. The latest manual now states 5500 rpm WOT at 2500 feet MSL. I ended up having to increase the pitch slightly to get that. I was at around 25.5 before that and had to increase to 26 after I saw that in the revised install manual. I originally set it for 5500 RPM at 5500 feet which is my average/normal cruise altitude. Don't think it'll make that much of a difference though, as I didn't really even notice a change overall. Ah, thanks. Mine does 5500 at 2500ft where I usually cruise when flying locally, so I guess I just happen to be right on the current guidance. I'm sure you're right, the difference between 5500 at 2500ft and 5500ft has to be minimal, probably less than half a degree. Quote Link to comment Share on other sites More sharing options...
Madhatter Posted May 31 Report Share Posted May 31 The digital protractor that comes with the prop is only good for the first blade, it's too inaccurate for repeatability. After using it on the first blade then use a machinist bubble protractor to match all the blades. A real machinist bubble protractor has extremely accurate repeatability. Bubbles don't lie. Quote Link to comment Share on other sites More sharing options...
DJ Todd B Posted May 31 Author Report Share Posted May 31 So, trying comparing Apples to Apples... Since the aircraft, engine and blades don't really know that they are at the altitude of 2500 and 5500 MSL, shouldn't these numbers be taken and tested at the DENSITY Altitude reading instead? Today I was at 5500MSL with A density ALT of 7200. I don't see how that would be a fair comparison at 5500MSL and DENSITY ALT of 4500'. When I took at 1400' MSL, My DA was already 3500'. Your thoughts??? Quote Link to comment Share on other sites More sharing options...
Eddie Cesnalis Posted May 31 Report Share Posted May 31 4 hours ago, DJ Todd B said: So, trying comparing Apples to Apples... Since the aircraft, engine and blades don't really know that they are at the altitude of 2500 and 5500 MSL, shouldn't these numbers be taken and tested at the DENSITY Altitude reading instead? Today I was at 5500MSL with A density ALT of 7200. I don't see how that would be a fair comparison at 5500MSL and DENSITY ALT of 4500'. When I took at 1400' MSL, My DA was already 3500'. Your thoughts??? Yes the correct target is density altitude. Setting for a 'typical cruise altitude' isn't precise. East/West typical cruises vary by 1,000' for example and density altitude is ever changeing. When cruising and limited to 5,500 and you realize 5,500 @ WOT you are cruising at best speed. If your throttle is retarded at 5,500 you have partial power and are pitched for best speed at a higher DA. If you'r WOT is less than 5,500 you are pitched for best speed at a lower altitude. Quote Link to comment Share on other sites More sharing options...
Garrett Gee Posted May 31 Report Share Posted May 31 6 hours ago, DJ Todd B said: So, trying comparing Apples to Apples... Since the aircraft, engine and blades don't really know that they are at the altitude of 2500 and 5500 MSL, shouldn't these numbers be taken and tested at the DENSITY Altitude reading instead? Today I was at 5500MSL with A density ALT of 7200. I don't see how that would be a fair comparison at 5500MSL and DENSITY ALT of 4500'. When I took at 1400' MSL, My DA was already 3500'. Your thoughts??? Fair point, should be density altitude of 2500 feet MSL. Quote Link to comment Share on other sites More sharing options...
Murray sibbeston Posted June 10 Report Share Posted June 10 I have my Ctsw on floats. I wonder if setting it with a finer pitch will actually decrease my performance? I suppose I better experiment a little rather than assuming I needed to use a bit less pitch. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted June 10 Report Share Posted June 10 Is this an Eprop? Up to 5800 at take off is acceptable with the engine and it will be a good climb prop, but you'll lose cruise speed and fuel economy. Quote Link to comment Share on other sites More sharing options...
Murray sibbeston Posted June 10 Report Share Posted June 10 Yes. An eprop. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted June 17 Report Share Posted June 17 26.5 worked for my CTLSi. It took a few tweaks to get it dialed in. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 17 Report Share Posted June 17 36 minutes ago, Bill3558 said: 26.5 worked for my CTLSi. It took a few tweaks to get it dialed in. I'm guessing the exact perfect pitch for any particular airplane is dependent on a lot of factors like engine angle and thrust line. CTs can have large variances on this. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted June 17 Report Share Posted June 17 Even depends on where you live and altitudes you fly at. Quote Link to comment Share on other sites More sharing options...
Batjac Posted June 18 Report Share Posted June 18 With my blades at 27 degrees I get 5450 at cruise, 5500 if I get it on step. Quote Link to comment Share on other sites More sharing options...
Jim Meade Posted June 18 Report Share Posted June 18 My measurements are about 63 degrees, but I measure it differently. None if it matters at all. All that matters is RPM at WOT at the desired altitude. Ah, yes. "on the step". Pass the popcorn. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 18 Report Share Posted June 18 3 minutes ago, Jim Meade said: My measurements are about 63 degrees, but I measure it differently. None if it matters at all. All that matters is RPM at WOT at the desired altitude. Ah, yes. "on the step". Pass the popcorn. Assuming you're measuring by the reciprocal of others' measurements, you are right at 27° (63 + 27 = 90). Quote Link to comment Share on other sites More sharing options...
Eddie Cesnalis Posted June 18 Report Share Posted June 18 Now that I live at sea level and still cruise at higher altitudes my 5,800 RPM limitation can be reached. My 5,500 DA is above 10,000. I can cruise above 125kts at various altitudes. My CTSW with a very flat Sensenich is crazy fast. Quote Link to comment Share on other sites More sharing options...
Towner Posted June 18 Report Share Posted June 18 Are most of you cruising near max rpm on cross country trips? I still have the neuform prop, but I tend to cruise between 5100-5200 rpm just for noise and fuel burn. My plane already seems slower than most at about 117 true at 5500 rpm, but I can’t see buying the new prop for just a little more performance. We already out perform most two seat production planes. I’m pretty happy with what I get now. I live at sea level, but it’s not uncommon to see 9000-10000 feet to travel anywhere and get over local mountains. Sorry to get off the topic of prop pitch. Maybe I’m just hoping someone can help me justify going e-prop! Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 18 Report Share Posted June 18 1 hour ago, Towner said: Are most of you cruising near max rpm on cross country trips? I still have the neuform prop, but I tend to cruise between 5100-5200 rpm just for noise and fuel burn. I like 5100rpm for traveling if I'm not in a hurry, it's quiet and still fast enough with good fuel economy. 5200-5400 is a good range if you're trying to make good time, you'll gain some speed from the higher rpm but the fuel burn will go up. Above 5400rpm you're mostly just making more heat and noise, you'll gain a knot or two but the fuel burn goes through the roof. When I'm just puttering around the local area (honestly most of my flights) I'm at 4800-5000rpm. Quote Link to comment Share on other sites More sharing options...
Anticept Posted June 18 Report Share Posted June 18 I use whatever RPM gives me Carson's Number, more if there's a decent headwind. https://www.aopa.org/news-and-media/all-news/2010/december/01/technique-cheap-speed Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 18 Report Share Posted June 18 9 minutes ago, Anticept said: I use whatever RPM gives me Carson's Number, more if there's a decent headwind. https://www.aopa.org/news-and-media/all-news/2010/december/01/technique-cheap-speed Hmm...according to that article, the number is found by best glide x 1.316. Best glide at -6° flaps is 78kt. So that number for the CT is 78 x 1.316 = 102.6kt. That is awfully slow...102kt indicated might be a good number at 10,000ft to give a good TAS cruise speed, but at lower altitudes it would not be ideal or even good. 102kt indicated at 4000ft would have me chugging along at something like 4500rpm. Maybe I'm missing something? Quote Link to comment Share on other sites More sharing options...
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