I was thinking , the spoil of the lift was primary, plus less stress on the structure. Would the spoil of the lift still be the same?They'll be lighter, but create less drag. Probably not a significant-enough reduction in drag to actually matter for their intended use, but still.
The use of the name "spoiler" by the soaring community is a misnomer. They're drag brakes, and their primary function is to increase drag, and be able to modulate that increase by the amount of deployment. The most-common usage is during pattern work and final approach, with the same function (but inverse actuation) as a power pilot would use throttle. Sailplane pilots tend to set up an approach that's a little high, and then modulate the glideslope with the "spoilers", by adding and removing drag instead of thrust.I was thinking , the spoil of the lift was primary, plus less stress on the structure. Would the spoil of the lift still be the same?
What would you recommend?...Depends on whether you are trying to spoil lift or create drag. Any large protrusion above and in front of the thickest point of the wing will spoil a lot of lift. Drag is proportional to the amount of flat plate area facing into the airflow.
This is why there are various different devices "spoilers", "air brakes", "drag brakes", "speed brakes", and "dive brakes". We tend to use theseterms interchangably, but there are technical differences.
I am guessing that the holes will put less stresss on the structure, and thus be able to be opened at a higher speed without ripping out of the wing. But less stress on the structure ALSO means less effect on the aircraft in flight.
To address this in the design phase, you will need to first decide what type of effect you want these devices to have on the aircraft, and with what limitations in speed. Do you want them to simply give you a little help here and there when picking your landing touchdown location, or did you want to pull the lever at 10,000 feet sucked up into in a cloud and have them guarantee you will not exceed Vne coming out the bottom of the cloud vertically?
I copied the size of the Woodstock another of Jim's design, but decided my type was cleaner, with less chance of lifting in flight. The Woodstock was the forward hinged flat plate style. Woodstock is simpler less prone to binding but was worried about lifting in flight, I worry about binding of my design hence the thought about holes.Airbrakes like these have so many quirks and subtleties and gotchas that I would stick with what's in the plans until a need to deviate is demonstrated. Once they work, they work great, but making them deploy, stow, and seal properly under a wide variety of operating conditions is a bear.
What do you want to achieve?
So the as-designed Carbon Dragon doesn't have airbrakes? Hmmm...I copied the size of the Woodstock another of Jim's design, but decided my type was cleaner, with less chance of lifting in flight. The Woodstock was the forward hinged flat plate style. Woodstock is simpler less prone to binding but was worried about lifting in flight, I worry about binding of my design hence the thought about holes.
After an early pilot was not able to land until after dark and the wind died, they added a large paddle over the aft fuselage,....It has been reported that it worked but was difficult to actuate. Another builder added the Woodstock type and reported large pitch changes on actuation. Phil in Ireland has the Schempp-Hirth style and destroyed a plastic wheel the first time he actuated it. He needs to refine his actuation system before more reports may arise.So the as-designed Carbon Dragon doesn't have airbrakes? Hmmm...
I had the spoiler caps suck out and flutter up and down on those springs one beautiful day, in a near-vertical dive through the start gate at a national level contest. Please accept my sincerest assurance that you don't want this to happen to you if you can avoid it. Anything less than a brand new LBA certified German-engineered racing sailplane would likely not have gotten through that episode with just a few cracks in the gel-coat.But I would still have an overcenter mechanism to keep the airbrakes from sucking out.
that type is what was added to the Carbon Dragon when they decided to add one as an after thought. My thoughts here are that is purely drag and does not spoil the lift..... All of my glider experience has been with aircraft with "spoilers" on the wing.Look at the speed brake on Maupin\Culver's Windrose. Pops up from the top of fuselage. Probably is held down by air pressure.