The Depron Skyray doing a 'Vulcan'

[Simon Chaddock]

As the previous videos have shown despite being a ducted prop the Skyray is surprisingly noisy.

Tonight was absolutely still so good conditions to explore the limits of its flight envelope.

1.It has a rather alarming tendency to 'tuck under' at speed so in a high speed (relatively!) dive it is best not to get too close to the ground before starting to pull up.

2. As might be expected from a delta is doesn't really have a stall, simply at some alpha the drag exceeds the thrust and it almost stops. Motor torque then makes it roll out to the left.

3. Its thrust does not exceed it weight but is quite close so it can climb for some time at a very steep angle. If correctly positioned you can actually see right through the duct and with the prop right at the back pointing directly at you it is loud.

On the last attempt I cut the power completely at several hundred feet and let the nose gentle drop into a glide - silence!

 

It reminded me of the Vulcan (when in RAF hands) doing its party piece departure when the thunderous roar of a full power (20,000lbs each in those days) very steep climb suddenly stopped as it throttle back at altitude.

[Erfolg]

You may be interested to know that an AVRO 707 exists in the Manchester Air and Space Museum.

 

Whilst speaking to an ex B58 pilot, he mentioned that the airplane porpoised at speed, if care was not taken. Although I guess a model never gets anywhere near the speed for it being an issue for a model. Perhaps more relevant, he spoke about getting to the back edge of the drag curve, due to as is now called high alpha, or angle of attack, to us oldies. Where adding more power just pushed the aircraft forward faster, whilst it continued to sink. The answer was not to get there in the first place, as the situation was terminal whilst landing, at higher altitudes, the answer was to put the nose down.