work in Festo type quick connectors. I prefer
barb type joiners, since they are a lot lighter
than a bunch of quick connects!
Lastly it’s important to ensure that no part of
the leg or wheel touches any part of the air-
frame when retracted-legs that don’t retract
can also be because they are hard against
part of the airframe. This removes the wor-
king clearance on the sliders needed to ope-
rate freely. With the gear retracted can you
freely rotate the wheel? If you can’t you either
need to relieve the area under the wheel, or
pack the unit with a thin wedge to change the
angle. It only requires a very thin shim to
move the end of the leg a few mm.CROW or Not to CROW
There seems to be lots of talk again about
whether CROW (raised ailerons with landing
flap) is needed and even good or bad.To answer the question best, it depends on
the airframe. It can even vary with the final
set up on your chosen model. Flying weights
vary massively, even on the same airframe.
Your choice of equipment and finish will
change the weight enough to affect the way a
model flies. This can change whether CROW
is needed or not.
A large aeroplane with ample wing area
would be a better candidate for CROW. If we
compare an Ultra Lightning sports jet to an
Ultra Flash, think about the fact that the turbi-
ne, and all radio equipment probably weighs
exactly the same over these two airframes.
The wing area is much larger on the Ultra
Lightning, so it is a good candidate for
CROW, it has a long flat glide slope and very
little natural drag. The UF does not need it
since the wing loading is higher and natural
descent rate increased.
The UL needs a reasonable amount of raisedaileron to be of use - I'd start at 10mm, this
removes some lift and coupled with enough
flap you will be able to pin point your lan-
dings.
I really prefer the Ultra Flash without any
CROW, it has a higher wing loading and big
flaps. If you insist in using some CROW,
3mm is as much as I would go before you
have to start reducing flap angle to replace
lost lift.
There are so many variables that can affect
the success of adding CROW, but i’d say
lighter loaded airframes that float on landing
are a reasonable candidate for it. Adding too
much to heavier loaded airframes just remo-
ves more lift and makes the stall, when it
does come, more severe.
I’ll come back to CROW another time, it
requires a lot more detail to cover all of the
things that need considering.STARTING WITH TURBINES
This Cougar can benefit from CROW as it has lots of wing area and lacks elevator authority caused by a large pitch down on full flap.This Ultra Lightning is easier to land with CROW.Articolo Dave_Layout 1 07/03/18 15.36 Pagina 5