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Prop Settings - Max Static RPM?


SkyrangerRich

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Hi SkyRanger Rich,

I, too, have a 2006 CTSW and initially, the Warp Drive prop was geared (by the then UK importer) for about 4,500 max static.  This was terrible both for take-off performance, gearbox wear and top speed.  After a few months of ownership (and reading all the posts regarding this topic on the forum) I paid 'lip service' to the BMAA TADS and set my prop a few degrees finer.  After much experimenting, I now have about 4,900 max static and 5,500 WOT straight & level at 2,000ft AMSL.  This gives me between 1000-1100 fpm climb rate with half full tanks and 2 pilots at sea level and ISO standard temp & pressure.  I find this is now the perfect setting for me - and I have to get in & out of a 250 metre farm strip with trees at both ends!  The only 'negative' was the fuel consumption which went from an average of 16-17 litres per hour to 17-18 litres per hour but I was cruising at slightly higher speeds.

Another good thing about a finer prop pitch is the throttle/performance pick-up is much more responsive when low to the ground and with a low airspeed for, say, a go-around.

Your post seems to indicate that, at first, your prop was pitched slightly too fine but the workshop have now set it slightly too coarse!  You need to set it somewhere in between.  I'm sorry but off-hand, I can't remember the exact number of degrees that I have set my prop but if my memory serves me well, I think it was 21 degrees using the Warp Drive protractor. 

After 16 years of ownership and 1200 hours of flying my CTSW, I have no issues with my current prop pitch setting and I have yet to find a strip that I can't get in or out of with regards to engine performance.  And I personally very rarely, if ever, use +30 or +40 flap!  However, as I teach pilots to fly CTSW's, I am very familiar with all the 'gotchas' and points to be aware of regarding the higher flap settings and ensure that CT owners are not unnecessarily apprehensive  about landing with +40 flap. 

 

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I did a huge one of a kind prop research project several years ago with 14 different props. Different lengths, 2 blade vs 3 and different flex-abilities. . Get rid of the Warp Drive prop. It suffers in climb no matter the setting compared to other props. I also know this because at the begining with my CTSW I had a Warp Drive. Also set the WOT rpm to 5600-5650 rpm which is the best all a round WOT rpm, but if you need better climb still set the WOT rpm to get around 5750-5800.

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Hi. 
Thanks for prompting me to update this thread. 
I only flew with the coarse prop settings for a few hours (less than 3), although I was initially amused that I could get 125 knots at 4900rpm, the aircraft was actually quite unpleasant to fly, no take off performance and extremely pitch sensitive, making it kind of porpoise through the air, it also ran warmer than before and used more fuel. 

Very strange that the importer recommended that setting, 4750rpm static. 

I’m now back to almost where I was before, 4900ish static, 5600 in the air. Speed per rpm is down (obviously), but those speeds are still available, just higher up the rev range. Take off performance is back and it’s a joy to fly. 
 

I would really like an e-prop and could justify a replacement prop as mine is starting to look a bit tired, however here in the UK the only approved props for the CT are Neuform and Warpdrive. I may investigate what it would take to get the e-prop added to the list. 

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Hi SkyRanger Rich,

I think if you wanted to go to an E-Prop, you might want to talk to Rob Mott at the BMAA and point him to the fact that other markets are using them on their CT's.  It might be classed as a Major Mod but I would think it doable.  I have just fitted a Bendix King xCruze100 (TruTrak Vizion) auto pilot to my UK CTSW and the journey was relatively easy regarding the paperwork.  I had to strengthen the 'tunnel' for the roll servo and the cockpit floor for the pitch servo as well as making all my own servo mounts, pitch servo pushrod, pitch servo protective cover and wiring loom but I got there in the end!  I would think a prop change should be a lot easier to get through. If you decide to make enquiries, keep me in the loop as I would think a lot of UK CT owners would be interested.

Regarding the importer setting my prop as he did back in 2006, I believe he was just following the advice that came from P&M Aviation and the BMAA TADS.

Paul  

Edited by gorilla
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