CT4ME Posted April 1, 2015 Report Share Posted April 1, 2015 As the C4 gets closer to flight tests... the prop has been announced: http://www.aviationpros.com/press_release/12060478/hartzell-to-supply-flight-designs-new-alternative-fuel-c4-with-2-blade-swept-props Link to comment Share on other sites More sharing options...
Anticept Posted April 1, 2015 Report Share Posted April 1, 2015 I was visiting hartzell props last year. I got to see them as they developed the prop. Strange that they decided to make a two blade. The one they were developing was a three blade. Link to comment Share on other sites More sharing options...
gbigs Posted April 1, 2015 Report Share Posted April 1, 2015 As the C4 gets closer to flight tests... the prop has been announced: http://www.aviationpros.com/press_release/12060478/hartzell-to-supply-flight-designs-new-alternative-fuel-c4-with-2-blade-swept-props Well, it is clear now they are going for Euro standards for fuel, noise and low performance (145ktas). Too bad. The low $250k price target (will no doubt be $300k by the time the first planes come out next year) was gonna be great as long as they made a decent four-seater that could at least do 180ktas on the top end. And it would have been even better if they had kept the HP up and lowered the compression and made a 91E10 engine instead of the useless 94UL non ethanol we can't get in the USA widely or at all. Also, it would be nice if they get rid of the steam gauges and put in a GRT small glass backup. And it won't do them much good to have the GTN750 for IFR flight if they don't also put in lightning protection and the possibility of a de-ice option. The CD155 TCM diesel is also a useless engine turns out. It has a TBR (not TBO) of 1200 hours and a gear box that has to be overhauled every 300 hours and is a meager 155hp. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted April 2, 2015 Report Share Posted April 2, 2015 A two blade prop is more efficient than three blades. Three blades look better IMO, and they are a little quieter, but this is a change FOR efficiency, not against. Link to comment Share on other sites More sharing options...
Anticept Posted April 2, 2015 Report Share Posted April 2, 2015 Two blades are more fuel efficient and have a tiny bit higher cruise, three blades convert more torque to thrust and perform better on climb, and are quieter in the cockpit. This assumes, though, that we're talking about the same blade profiles . Link to comment Share on other sites More sharing options...
gbigs Posted April 2, 2015 Report Share Posted April 2, 2015 A two blade prop is more efficient than three blades. Three blades look better IMO, and they are a little quieter, but this is a change FOR efficiency, not against. From Hartzell: If 2-blade propellers are more efficient, then why don’t all propellers have 2 blades? The short answer is because efficiency doesn’t propel the airplane, thrust does. The most efficient propeller blade count for a particular aircraft is a function of the aircraft mission and a number of other factors. These include the amount of engine power, operating RPM for the propeller, diameter limitations, aircraft performance requirements (high speed cruise, takeoff, loiter, etc), noise requirements, and others. Depending on the combination of these parameters a 2-blade propeller may be most efficient, but as power increases additional blades are generally required to efficiently utilize the increased power. My comment: FD is going after noise reduction and forgoing increased thrust, faster climbs, and faster cruise. They detuned the engine from 195 HP to 180 HP and lowered max RPM. They are making a SLOWER aircraft which makes their price point less appealing. And that's a shame. Link to comment Share on other sites More sharing options...
Anticept Posted April 2, 2015 Report Share Posted April 2, 2015 Aircraft manufacturers always tout higher numbers than what you get at delivery. It's been that way for many many years. When I first heard about 155+ knots I was skeptical from the beginning. Link to comment Share on other sites More sharing options...
gbigs Posted April 2, 2015 Report Share Posted April 2, 2015 Aircraft manufacturers always tout higher numbers than what you get at delivery. It's been that way for many many years. When I first heard about 155+ knots I was skeptical from the beginning. What are you saying? FD is making an even slower plane? Right now, they are doing little more than making a little cheaper Cessna 172. Maybe that was their plan from the start...If they want to capture a little of the Cirrus market, where most of the sales are, they should at least offer one of the other 210HP IO-360 engines. The USA market doesn't care about noise or 94UL. Even better, fit one with an IO-550-N...the same engine the Cirrus Sr22 non turbo has, then we are talking real capability. I would pay them a premium to get the C4 with a 190ktas top cruise. Link to comment Share on other sites More sharing options...
Anticept Posted April 2, 2015 Report Share Posted April 2, 2015 I'm saying I am not surprised if they don't hit their target. Link to comment Share on other sites More sharing options...
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