- May 30, 2020
- Reaction score
I prefer vertical rudders, as I've tried the "tilted rudders" (aka V-tail) and they needed to be larger than a vertical rudder to provide the same amount of yaw control. That being said, if a design could benefit from more aft weight, I believe a larger V-tail would add dihedral. For example, the Holverson Swinger's wings have zero dihedral; the only dihedral is provided by the large V-tail, and it glides fine.For future ideas, wondering if, in situations where you need extra tail weight with or without additional rudder surface area, replacing vertical rudders with larger rudders tilted vertically laterally may help.
The larger rudders will increase your tail weight as needed, the tilt gives you an bit of effective diehedral and maybe a bit of lift even when glide is level.
How much pod downthrust would be required to compensate, an amount equal to the flap angle? If the flap's angle is 1.5°, would a pod angle of -1° be enough? Or would that be too much? I built in a -1° angle in my pylon but if it's insufficient I could always remove and resand the pylon in a spare moment to salvage this "trial run" version.Eric,
Since you added a "flap", it might cause a tendency to loop during Boost.
The cure for that would be slightly more Downthrust Angle on the Pop-Pod.
The Swinger in that video "glides like a brick" . . .For example, the Holverson Swinger's wings have zero dihedral; the only dihedral is provided by the large V-tail, and it glides fine.
The Swinger was simply an example of apparently using dihedral in the stab vs the wings in answer to BABAR'S question.The Swinger in that video "glides like a brick" . . .
The "Glide Circle" was way too tight and Glide Speed was quite high ( I suspect a Forward CG location ) . . . The result was more of a "Spiral" than a flat glide.
When you see a real "free-flight" Competition B/G or R/G in flight, you will instantly see the difference !
The video's below show a "high-performance glide" by comparison . . . Yes, the mass would be higher for a rocket-powered glider, but the comparison is valid.
Remember that these flights are INDOORS with ZERO thermal activity ! ( The last video is a world record flight of nearly 2 minutes ! )
Having the same problem with my clone. Fortunately I acquired an original in- the-bag kit and I'm looking forward to building and flying it to see if it flies any better, and if so, why?Eric,
I've seen Holverson Swinger's turn in some very good flights. The glider in that video appeared to be the victim of bad trimming.
Per your first article: "The designer has typically arrived at a design by the built it, fly it and then build another one with some small improvements". I'm strongly considering doing just that with this build and the Icarus build to get both gliders as close to optimum as possible. Call it curiosity (or maybe obsessive-compulsive lol).Eric,
Here are a couple of interesting articles . . .
I like the idea of the high-temp paint ( probably less Mass than Tape ).Suggestion on what I can do on the version 2 model since the fuselage runs above the wing surface?
High-heat paint? Trying to manhandle that sticky tape would be a nightmare; it wrinkles with the slightest bend and once any part touches the surface it sticks tenaciously and is almost impossible to pull up without damaging the surface. I pretty much only get one shot at it and I’d really hate if it ended up looking like a piece of crumpled aluminum foil was just stuck down to that fuse spine.
No worries, deltas don't require dihedral.Eric,
Looking at the photo with Version #1 & #2 got me thinking about something that may not "crop up", until Flight Testing.
I am concerned that this design, both Version #1 & #2, might either "choose" to Invert or to remain inverted, if it happens to get into that flight orientation . . . I think this might, most likely, occur at Transition, or if the Glider were to Stall.
My hypothesis is based on :
(1) Zero Wing Dihedral.
(2) Upright Vertical Rudders ( as opposed to "under-slung" ones ) may tend to act as a "pendulum", if the Glider "inverts".
(3) Canard Dihedral - The Canard, even with Dihedral, might not create sufficient force to "right" the Glider, if it "inverts".
(4) The Angle of Attack of the Canard might induce a "Dive", if the Glider "inverts".
Just a "concern", hopefully unjustified !
I was thinking that "dihedral effect" might encourage an inverted glider to right itself . . .
What is the source of info for delta wings not requiring dihedral ?
I would like to read more about that.
Thanks for the info . . .Excerpt:
"An additional reason for using swept or delta wings is that they exhibit a beneficial dihedral effect. When an airplane is in a roll, it tends to side-slip to the inside. Dihedral creates a rolling moment, tending to roll the airplane upright. Swept and delta wings exhibit this characteristic. For example; the wing on my canard has no dihedral, but the 35-degree sweepback provides dihedral effect. An advantage in using a swept or delta wing and no dihedral is that the airplane will exhibit the same dihedral effect when upright or inverted. Still another advantage is a beneficial effect added to the airplane's directional stability. "
I never bothered to download the math/formulas and aerodynamic physics behind why, they were too much for me to deal with, but I'm sure you can find additional tech articles with them online.
Also mentioned in attached pdfs:
IDK, maybe the physics of a plane that much larger isn't quite the same?Thanks for the info . . .
I was thinking back to when the REAL XB-70 Valkyrie crash happened . . . The F-104 stuck the Right Wing and got caught in the Tip Vortex from the Drooped Wingtips and was flipped across the top of the Valkyrie, shearing off both Vertical Rudders in the process.
I wonder why the "dihedral effect" of the Delta wing did not permit an emergency landing, especially since the Wingtips were "drooped" at the time ?
I suspect that other forces may have been at work, as it was under power versus being a glider. Airspeed, torque from the engines, the fact the part of the right Rudder remained, after impact . . . The fact that the Pilot was, initially, unaware there was a problem . . . Probably others, too !IDK, maybe the physics of a plane that much larger isn't quite the same?
Great hinge material, but unfortunately I found out the hard way that it can't stand up to the heat of motor exhaust (it's basically plastic with a super thin layer of aluminum on its surface).Mylar tape?