?
what aircraft you have?xair or falcon ?
?
during initial flight testing aircraft is actually flown
to Vd which is over the Vne but that is for design approval
purposes,
Vne speed is set during loading calculations, i.e. all the
loads applied to the airframe are based on this speed,? there are safety
factors built in but this is where Vne comes from and cannot be changed without
further load testing (not flight testing)
?
?
----- Original Message -----
Sent: Friday, July 27, 2018 1:03 PM
Subject: Re: X-Air Ultralight Aircraft
Re: Indicated airspeed problem
?
? VNE is 85 knots or 98 mph, however during the original testing of type in
England, the aircraft was flown over VNE? to 95 knots or 109 mph.
Not that I would
recommend flying at 95 knots, the original test pilot had a BRS parachute
fitted, something the BMAA? won’t let me fit without retesting the whole
aircraft.
Regards,
Jon
John you mention 95knots its 95mph (83kn)
?
----- Original Message -----
From: mailto:avia1or01@...
[X-Air_Ultralight_Aircraft]
To: X-Air_Ultralight_Aircraft@...
Sent: Friday, July 27, 2018 9:25
AM
Subject: X-Air Ultralight Aircraft Re:
Indicated airspeed problem
?
?
This is all well and good, however if the aircraft has been changed
since it was built it could be that the MAAN figures used by the BMMA are
incorrect and they could potentially be asking members to fly their aircraft
significantly over VNE.
?
I solved the problems with my own aircraft and got my permit. I took
advice from various experts and then flew the VNE test again.
?
Before re-flying the the VNE test, I made a rough calibration myself to
check that I was not doing anything dangerous. I simply flew level at full
throttle into wind and then full throttle down wind and observed the GPS
speed and IAS.
?
The GPS speed was approximately in line with my expectations and so I
did the test. I actually did the VNE test twice, again into and down wind. (
there was little wind on that day ) During the test I kept an eye on the GPS
speed and ensured that it never at any time exceeded 95 knots.
?
Which is 10 knots faster than VNE and also the maximum speed achieved
by the test pilot during certification of the the aircraft. By coincidence,
my particular aircraft was the prototype used in the original testing and so
I know it has flown at 95 knots previously.
?
I am very concerned that other owners may be persuaded to fly their
aircraft at dangerous speeds and I have heard stories of X airs being pushed
to a near vertical dive to achieve the required indicated airspeed.
?
To me that suggests they may well have been flying too fast. Mine
achieved VNE with a steep dive on full throttle, it was not vertical or
anything near it. I simply opened the throttle fully and when maximum level
speed was achieved, I pushed the nose down and allowed the aircraft to
accelerate to VNE.
?
Aside from the these particular concerns, more generally I don’t see
the point of any test where the only two possible outcomes are either a pass
or a fatal accident.
?
Regards,
?
Jon
