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View Full Version : Spoiler deployment angle - too low!


fprintf
Nov 02, 2004, 07:33 AM
When I set up my spoilers via strings on my Marauder I can only get about 25 degrees of deployment when fully open. The single spoiler servo is a Hitech HS-85 with a full size arm on it, and there is (was) no binding of the arrangement.

I got so frustrated with trying to figure out why they weren't deploying that in my haste to get the plane flying again after a crash I just covered over the spoilers. Now that winter is here I have some time to fix these things.

Something tells me that I must have the geometry incorrect *or* I am not getting enough throw from the servo. But with a full size arm (fixed to slightly forward of perpendicular to the servo strings when closed) and the strings mounted to the outermost hold I think I cannot possibly get less leverage and more distance pulled at the servo end. The holes in the spoiler horns were pre-cut in the kit and are at the end of the horn.

Has anyone had to troubleshoot spoilers that did not open sufficiently before? If so, what did you do to get them to open at 45 or more degrees? As I had them set up the spoilers on my plane were marginally efficient.

John Ruff
Nov 02, 2004, 09:04 AM
Couldn't you put the servo arm all the way forward when the spoiler is closed , or did I miss something ?
John

solo6796
Nov 02, 2004, 09:58 AM
Try drilling another hole on the spoiler arm closer to the hinge line. That may help...

AJ

Al M
Nov 02, 2004, 10:26 AM
The hole in the spoiler horn wants to be forward of the hinge line. As far forward as possible.

Sparky Paul
Nov 02, 2004, 12:15 PM
A typical spoiler arrangement...
The pull cable attachment as far forward as possible.

SoCalGliderFlyr
Nov 02, 2004, 07:41 PM
Putting spoilers in an old BoT (possibly one of the Thornberg hand cut kits):

solo6796
Nov 07, 2004, 07:38 AM
SoCal,

Take care when installing your 1/8" balsa servo mounting. Do it with the servo attached, and adjust it so the spoiler will just about rest on the servo case when closed. It will give you better extension.

AJ

SoCalGliderFlyr
Nov 07, 2004, 11:47 AM
Thanks AJ. I haven't had time to actually play with the install other than to frame in the spoiler opening. Been busy laying out parts sheets for laser cutting. Still not certain if I will use the ply-balsa blades or dig some TE stock out of the scrap boxes. Suggestions?

Sure wish I could pin point this BoT. That is if this is one of Dave's hand cut kits or built from the plans or one of Mark's first production kits. The ribs are 3/32" thick and capped only on the top. The stabilator used the modified servo arm bell crank and square brass tube extension. The fuse sides are diagonally joined a few inches in front of the rudder.

solo6796
Nov 07, 2004, 02:17 PM
The TE stock seems easier...Might be lighter, and I think is plenty strong.

AJ

staggerwing
Nov 07, 2004, 02:34 PM
SO CAL
Sent you an e-mail about your installation as I'm planning on putting spoilers in a BOT

Bob

SoCalGliderFlyr
Nov 07, 2004, 06:10 PM
Bob, Replied to your e-mail. Have you looked at the other BoT threads here? AJ has one as well as ejett. Several different ways to install the servo(s) for spoilers depending on your build.

flyingdogtwo
Nov 10, 2004, 07:18 PM
Not a BOT, but here's one way to install with pull strings.