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Old 06-03-2012, 12:53 AM   #1
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Join Date: Aug 2010
Location: Vancouver, WA
Default New AT550-ARB-XT

Many thanks to KDE, I got a soon (early next week) to be released AT550-ARB-XT. The XT series upgrades are designated for DFC head. The AT550-ARB-XT is no exception. However, pilots with regular head can also enjoy the benefits of KDE AT550-ARB-XT provide. And it will still work perfectly after upgrading to DFC head.

The main difference between the original version and the XT version is the height. The XT version is lower and provides more clearance between the main grip arm and the top of the ARB. The original can still work with DFC head, though. I have been using the original version with DFC head over 100 flights without any issue.

This picture shows: Align ARB on the left, KDE AT550-ARB in the middle, and the new KDE AT550-ARB-XT on the right.

Here's the side view comparison. From this picture, you can clearly see one of the main design features of KDE ARB. The rail is thicker than the Align design. The extra material not only provides more strength. It also provides more surface area which means bind-free, wear-free, and smooth operation.

Here's the picture of KDE AT550-ARB-XT installed.

Another design feature of KDE ARB is the arc at the bottom of the rail and the cut of at the gyro mount. It provide more clearance for the elevator servo arm. I have read several posts on the Trex 550 forum complaining the elevator servo arm hitting the Align ARB under extreme position. This got me curious. So I did few tests.

Without powering up the servors, I moved the elevator servo arm up until it hits the gyro mount. I also moved the servo arms of the front cyclic servo to their lowest position. The RC Logger digital pitch gauge reads 21.7 degree.

Here's the picture when the servos are powered up with full positive pitch (13 degree) and full forward elevator stick (max cyclic is set at 12 degree). It still has plenty clearance.

There are few more pictures in this album

Picture worths thousand words. I will let you be the judge to decide whether this upgrade is worthwhile or just a bling.

Thanks for reading

HD750, TDR II, TDR, Logo 700, Logo 700 XXtreme, Logo 550SX V2, KDE motors on all helis
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