wrote in :

Bertie the Bunyip wrote:
es330td wrote in news:5a4af2c5-b74c-4e6f-be32-
:

Last weekend while doing my hour of going around the pattern in
preparation to solo my airfield was visited by a Dyke Delta home
built (link to a picture of one below.) I did a little research on
it and learned that it truly is a delta wing aircraft with a single
horizontal surface (some of these have a small T-tail but this one
did not.) Seeing it made me a little curious about the mechanics
of flying it. It has a vertical stabilizer and a rudder so I
assume the plane has pedals but with only one horizontal surface
the movable parts serve as both elevators and ailerons. I'm also
guessing that it doesn't have flaps, just as the main wings on
canards don't have flaps as additional lift that far aft would
result in a rapid descent.

Does anyone have any kind of experience with an aircraft like this
that can enlighten me on their flight characteristics?



I know a bit. They fly pretty much just like an airplane. The biggest
difference is that they don't stall in the same way as a
"conventional" airplane in that in most of them the flow doesn't
seperate from the top of the wing. What happens is as the airplane
slows the drag rises but so does the lift. When the drag rises to the
point that thrust is overcome they start to decelerate and the game
is over. So, given enough thrust, you can fly them at ridiculous
anges of attack and insanely low airspeeds.

OK, so then what happens?

Do they then tend to just decend level like an Ercoupe, tend to tumble
out of the sky in a totally uncontrolled fashion, or something else?


Well, depending on the power, it will get to a such a nose high attitude
that you'll nearly start going backwards! But seriously, it would depend
on the design, but it would just start losing altitude slwoly and then
more quickly as AoA and dra increased. the Concorde accidnent in Paris
is a good example of how deltas work, though. the power available to
that airplane required a given speed (V2) to keep the airplnae on the
correct side of that poser curve n the event of the loss of a single
engine. Since the FE shutdown a second engine just past V1, it was
unable to accelerate to V2 in the runway available, and it was tooo late
to stop, so the captain rotated below V2, on the back side of the drag
curve. The airplane was able to fly OK, but only at the expense of a
constant airsped tradeoff for lift. he kept bleeding speed off to get it
to climb, but only by increasing AoA and drag. Eventaully the drag ws
too much and it began to sink and with all that asymetric power he lost
directional control. A conventional airplane never would have got as far
as it did. Point is, he had a large surplus of lift available even
though he took off at too low an airspeed.


I have a friend who used to fly the Avro Vulcan. He told me the airplane
would fly to very low speeds indeed and could turn in extrmely small
radii because of it's ability to fly so slowly. Roll rate was almost
fighter like and the airplane was apparently a joy to fly in every way.
They're pretty impressive to watch ( and hear) fly..


Bertie