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Old Mar 12, 2011, 01:28 PM
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Brentwood, California
Joined Jul 2007
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The +'s and -'s of electric retracts on large jets

Iím new to electric retracts, just bought my first set for my new Habu. This craze has been building for some time and Iíve watched from the sidelines. While I do see the benefits for smaller planes like the Habu or maybe even up to 60 sized warbirds. I wonder if pushing electric retracts into larger planes doesnít open up a whole new set of problems.

Take for instance the 1/6 scale Jet Legend Hawk Iím building. It has large heavy gear, brakes and wheels. The plane has 7 gear doors, 5 of which need actuators the other 2 attach to the mains. The plane already has 8 servos for flight controls, now you would need to add 5 servos to work the gear doors, bringing us to a total of 13 servos.

So I see several issues at this point. One being, setup would seem like more of a mess than air cylinders. If you donít have 13 channels you now have to add expanders, how do you set up end points? Next I know from experience that gear doors in general need a little pressure to stay closed tight, this could lead to power drain on your system. What if a gear door or landing gear become jammed like they often can? Now you are putting huge strain on your system that could lead to brown out. How do you work the wheel brakes that are air actuated?

I would see the need for larger RX packs that can handle the strain or isolate the landing gear and gear doors to its own power system adding more complexity to the plane.

I have been using air retracts with great success for many years, when setup right they work great. The fuel to power them is as light as you can get, air! So why the need to add complexity, increase the chance of stalled servos or gear that could suck down your flight packs? Or the need to add bigger heavy RX packs?

I guess I donít get it? Iím a missing something? Is this a craze that will pass?

Sure seems like a hot item and everyone is jumping on board.... I agree for smaller stuff, but for larger planes I don't see the benefit.

So if you plan on moving on to larger stuff don't forget your air system skills you are going to need them
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Last edited by Ron101; Mar 12, 2011 at 01:43 PM.
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