Airmaster Prop question

[SNOW JW]

For those of you with the 914 or turbo Rotax im curious if you thought the in flight adjustable airmaster is worth it for the STI wing.

[Kitfox Pilot]

915is and Airmaster here. It is great! Wouldn't want anything else for the way I fly. Climb out at 2k and cruise at 100mph on 5.5gal. Down side if the budget is tight I wouldn't have one cause they are pricey.

[efwd]

Trent Palmer recently posted a YouTube video where he explained how he came to replace his in flight adjustable for a ground adjustable prop. He is enjoying his ground adjustable. FWIW. It seems to be all in your mission. I for one can't wait to get an adjustable prop. Hopefully the light sport rules change soon and I can acquire the new prop that adjusts itself.

[tracstarr]

I've got a 912iS, normal wing and the airmaster. I've never flown without and never would. If it's in the budget it's absolutely a must have. You select take off/climb/cruise - it's that simple. You have the option to manually adjust in flight as well - but there's no need. They will setup the software to match the engine. On take off wheels up at about 37kts no flaps, I climb out normally at about 62 kts. Yesterday during my max weight (1550 lbs) testing I was climbing out at 708 ft/min average. Started at a density altitude of 1300 ft. I can likely do better as I was seeing 900 ft/min at some points. Switching to cruise IAS average was 72 kts @ 5000 rpms.

[P Johnson]

Interesting numbers as I am building the same set up with a 70” propeller, what do you have? I was expecting a higher cruise, what was the manifold pressure at that weight? as I believe it would have to be high to get you on the step.

[Shadowrider]

IMO on a STI wing (draggy and doesn’t like to go over 100mph) it depends on what you are looking for. We bought a NR props 79” 3 blade and planned on running them while we learned how to fly and then go to a constant speed. Well…..we never went to the constant speed. I can takeoff under 100’ climb at 2k cruise at 105mph at 5200. 5400 and I can go 110mph but it burns more fuel. You hit a drag wall at 100 and your fuel goes up a lot trying to go faster. You can fly high also if you like. I have been to 17500’ multiple times and haven’t ran out of prop yet. I routinely fly cross country at 14-15k. (With o2) This really only applies to a turbo engine though. Basically you pitch for cruise and on takeoff HP makes up for the lack of rpm’s. (5400rpm wot static) The lighter weight also makes up for the lower rpm’s.

What a constant speed would give us is you don’t have to constantly have to mess with throttle. We run vernier throttles so you are constantly twisting the throttle to maintain the rpm’s you are looking for. You can have max power on takeoff and always be dialed on rpm’s. If you are looking at flying cross country and not really concerned about weight then airmaster is the route I would go. As far as I know it’s the lightest option and the feather feature will really improve your glide ratio on an engine out.

[tracstarr]

Interesting numbers as I am building the same set up with a 70” propeller, what do you have? I was expecting a higher cruise, what was the manifold pressure at that weight? as I believe it would have to be high to get you on the step.

Mine is a 75". I do get higher cruise and can be closer to 80. That just happened to be the average I pulled off my debrief. MAP was between 14 and 22 during that flight.