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adding spoilers to my butterfly

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Old 10-17-2012, 02:26 PM
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Default adding spoilers to my butterfly

As suggested I will leave this powered glider rudder only as it was designed..( no ailerons ) I do want to add spoilers as our field is rather small.

Is the best place to put them on the inner wing panel on the TE just like they were ailerons?

I've seen where they put something on top of the wing that pops up? are these " speed bakes "?

thanks

Steve



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Old 10-17-2012, 03:01 PM
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Default RE: adding spoilers to my butterfly

Anything that sticks out into the airstream is a speed brake of sorts.

My gliders equipped with spoilers are on the top of the wing just at the spar location. When deployed, they kill lift and speed but also an abrupt trim change you have to be ready for.

Too close inboard, they may blank out the fin rudder, elevator so let those parts have some good clean air.

Mounted on the TE may give you lots of trim change as they are further aft of the lift polars. Besides lots of flutter of your flaps won't do you any good performance wise.

Ray W.
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Old 10-17-2012, 04:46 PM
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Default RE: adding spoilers to my butterfly

I experimented a lot on spoiler placement. I would place the spoilers LE at 50%, it would be 1 1/2" tall, 3 bays per side, and outboard of the stab.
Here's a picture of my scratch-built 120", the LE of the spoilers are at 55%. When the spoilers are deployed the plane pitch's up about 2°, slows a little, and sinks. If you want no pitch change go with the 50°. I like the slight pitch change and slowing, so I when with the 55%. If you want pitch-down and speeding up like is normally associated with spoilers go with the spoilers at the rear of the spar. The center-spoiler location only works with a computer radio, you need to compensate out the terrible pitching down that the center-spoiler causes, doing it by feel is just too hard.
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Old 10-18-2012, 12:36 PM
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Default RE: adding spoilers to my butterfly

The Butterfly wing is the same as the Windrifter glider wing. Built the Windrifter with spoilers according to the plans/instructions and they are 3/4" trailing edge stock, each 10" in length, and placed in the inner panels aft of the wing spars, with the outer ends of the spoilers next to the inner/outer wing panel junctions. Worked nicely with a single servo in the fuse and cord to each of the spoilers. No tiny servos in those days to place them within the wing next to each spoiler.
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Old 10-18-2012, 02:07 PM
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Default RE: adding spoilers to my butterfly

I would do as soarrich suggest. Out of the stream for the tail and moved back to a more efficient placement. You are flying for fun and not under rules like AMA. I have a Craft Air kit, and spoilers would be minimum, yet I would prefer flaps.
Another opton, could be dual spoilers, top n bottom, like some do on the M&M Marauder as these reduce the pitch change, plus can drop her like a rock if desired.
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Old 10-19-2012, 01:52 AM
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Default RE: adding spoilers to my butterfly


THANKS FOR The pic soarich, I like the location of your spoilers, any info on linkage/set up/hinging? I,
've never set anything like that up. Like to try something different.

Steve




Quote:
ORIGINAL: soarrich

I experimented a lot on spoiler placement. I would place the spoilers LE at 50%, it would be 1 1/2'' tall, 3 bays per side, and outboard of the stab.
Here's a picture of my scratch-built 120'', the LE of the spoilers are at 55%. When the spoilers are deployed the plane pitch's up about 2°, slows a little, and sinks. If you want no pitch change go with the 50°. I like the slight pitch change and slowing, so I when with the 55%. If you want pitch-down and speeding up like is normally associated with spoilers go with the spoilers at the rear of the spar. The center-spoiler location only works with a computer radio, you need to compensate out the terrible pitching down that the center-spoiler causes, doing it by feel is just too hard.
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Old 10-19-2012, 08:06 AM
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Default RE: adding spoilers to my butterfly

The hinging is just stick Monokote, from the 4"x36" sheets they sell.
The spoiler is a piece of balsa 3/16" x 1 1/4" x slightly less than 3 bays long, then a piece of 1x64" x 1 1/2" x slightly more than 3 bays long ply. The ply is flush with the edge of the balsa at the forward edge, then hangs over the other three edges to seal the spoiler bay.
The servo was a small servo that mounts through one of the ribs, then is connected to the control horn with a metal push-rod. I molded my CF control horn, but any small horn will work.
The picture of the foamy shows an easy way of making small push-rods with "Z" bends on both ends. You take an make 2 short lengths with a "Z" bend on the opposite ends, slide them into a length of shrink-tubing, adjust the length to what you need then shrink the tubing and apply CA for a permanent fixed length rod.
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Old 10-20-2012, 09:04 AM
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Default RE: adding spoilers to my butterfly



As noted above, spoilers are usually just behind the spar. Some swing up, called barn door spoilers. Some come up like blades. You can make them out of trailing edge stock, flat stock or buy comercially made spoilers that drop in.

If you have a computer radio with Flap to elevator mixing, set up the spoilers as if the were flaps. Normally as you engage the spoiler the wing will drop as you are killing the lift. You want the glider to continue in a more or less flat glide rather than dive, so you usually add up elevator in the mix.

Now when you add the spoilers the glider does not dive, it simply comes down at a steeper angle of glide. That is why these are called glide path controls.

spoiler kit
http://www.hobbyking.com/hobbyking/s...ight_Pair.html

These are the blade types
http://www.hobbyking.com/hobbyking/s...ated_2pc_.html

In the photos below you see my AVA and my Spirit (red and white) There is a shot of the servo in the wing to operate the spoiler. On the AVAthe spoilers are in the center section. They are the yellow sections.

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Old 10-20-2012, 01:39 PM
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Default RE: adding spoilers to my butterfly

thanks, servo shot helps allot. tape hing in the front?



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ORIGINAL: aeajr



As noted above, spoilers are usually just behind the spar. Some swing up, called barn door spoilers. Some come up like blades. You can make them out of trailing edge stock, flat stock or buy comercially made spoilers that drop in.

If you have a computer radio with Flap to elevator mixing, set up the spoilers as if the were flaps. Normally as you engage the spoiler the wing will drop as you are killing the lift. You want the glider to continue in a more or less flat glide rather than dive, so you usually add up elevator in the mix.

Now when you add the spoilers the glider does not dive, it simply comes down at a steeper angle of glide. That is why these are called glide path controls.

spoiler kit
http://www.hobbyking.com/hobbyking/s...ight_Pair.html

These are the blade types
http://www.hobbyking.com/hobbyking/s...ated_2pc_.html

In the photos below you see my AVA and my Spirit (red and white) There is a shot of the servo in the wing to operate the spoiler. On the AVA the spoilers are in the center section. They are the yellow sections.

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Old 10-20-2012, 02:02 PM
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Default RE: adding spoilers to my butterfly

I use clear packing tape or monokote.
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