F1 Evo -
Preliminary Performance Assessment
Team Rocket, in collaboration with HPAI, has begun the
flight test program on the F1 Evo
(evolutionary new wing design).
The new airfoil is an MS(1)-313. This airfoil series, along
with the LS(1)-xxx series, and the NLF series, were
developed by NASA in the seventies. Their testing shows a
potential 20% decrease in wing drag through use of these
air foils. A secondary positive side of these air foils is
that surface degradation through rain, or insect leading
edge contamination, does not cause a significant problems:
a contaminated airfoil still provides drag equal to our
current air foil, the NACA 23013.5.
As with any other experimental modifications, one change
begets multiple others. Of course, who can understand all
associated changes which will be required, until some
initial evaluation and testing is launched. And, as it
turns out, we have some further refinements to develop in
order to complete the testing with a resulting marketable
product.
Early test flight results indicate a slight cruise airspeed
increase, and an impressive stall speed decrease. Computer
modeling predicts a potential 5+% cruise speed increase,
and preliminary flight testing confirms this.
The cruise speed measurements are not final, by any means.
It turns out that the flaps will not fully retract –
they remain extended about 3-4 deg. This adds some amount
of drag due to the flap extension, but it also introduces a
significant amount of trim drag. Previous adjustments to
flying F1s showed a 5-7KT increase in speed when the
horizontal tail is properly adjusted, and it may be that
our cruise speed is affected in a similar manner. A new set
of flaps, with re-designed bracketry, will be installed,
and the horizontal tail will be adjusted to match the
resulting angle of incidence.
In addition, the flaps are a slotted design, and the
associated large hinge brackets will need to be faired in.
NASA testing of these air foils also indicated possible
high control system pressures, due to the heavy aft camber
associated with these air foils. High pressures are less of
a consideration in aircraft configured for cruising flight,
but high control system pressures are generally
unacceptable for aircraft whose missions include
maneuvering flight. NASA addressed these high control
system pressures by equipping their test aircraft with
spoilers instead of ailerons. From a marketing perspective,
adding spoilers to our aircraft is not an option. As a
first step, the control system pressures will need to be
addressed by internal system ratio adjustments, and servo
assist tabs as a secondary option.
We expect the new parts to be shipped to us and installed
for further testing in early February. We will post another
update after the second round of test flights.
Observations:
Preliminary stall speed ~50mph, 43.5KT
Preliminary cruise speed increase +2KT
Take off distance approximately -15%
Open Items (to be addressed):
Control system pressures – adjust internal ratios
Flaps do not fully retract – fabricate and install
new flaps
Install root fairings
Install wing tips
Install flap bracket fairings
Complete flap actuator redesign
Paint new wings