View Single Post
Old Dec 04, 2012, 01:21 PM
DanL is offline
Find More Posts by DanL
Registered User
DanL's Avatar
United States, MN, Brainerd
Joined Oct 2004
2,499 Posts
Sliding Servo Test Video

Pretty much confirmed the paper excercizes with a test mock-up of the forecourse geometry..
Mounted the sliding servo on a test base with a "yard" attached per the dimensions of the forecourse yard width and the onboard length of the braces.

- Transmitter: J&R 2.4GH 9ch. Channel set to +114% / -114% to get 4 full servo turns.
- Servo: HITech HS785HB, 6V nom., spec rotation = 3.5 turns, drum dia. = 1.53"
- Calculated brace pull per 2 rev's (2 stbd, 2 port) = 9.6"
- Actual brace pull per 2 revs = 10.75" (likely due to inreased dia. due to the "stacking" of brace line on the drum)
- Yard width, brace-to-brace = 24"
- Brace L, yard to drum, with yard squared = 32"
- Brace change in L, yard to drum, full rotation (64deg) = 10.75"
- Servo slide travel, squared yard to fully braced = 1.5" (slide has 2" travel max.)
- Tension: more than adequate retraction provided by 1/16" single strand of bungee on each side of servo.

See the clip for operation.
Rotation of 64deg was achieved. Onboard, due to shroud location, only a bit over 50deg rotation is possible. Having a bit of extra capacity in the hardware is probably a good thing, but the new drums will probably be a bit smaller in diameter than the current drums.
Servo setup did not have line guides installed.
Test did not factor in the vertical portion of the onboard brace run, but that should have little effect on yard rotation geometry.

Net assessment - worked very slick, smooth. No need for any bungee aloft, including the pendants. Very stable and repeatable positioniong.

Syren Brace Servo Test Setup (1 min 6 sec)
DanL is offline Find More Posts by DanL
Last edited by DanL; Dec 04, 2012 at 01:41 PM.
Reply With Quote