|
Gary Clemans-Gibbon
reviews the
Luna 400TM
from Flying
Wings
|
Flying Wings is a Norwegian business specialising in the
manufacture of simple, inexpensive foam flying wings. The range includes
the V-tronic (slow flyer, indoor, electric), the Tempra2
combat model (slope sailplane) featuring an EPP leading edge and the Luna
400 which is the subject of this review. The Luna can be built as a
slow fly or fast (depending on motor/battery size). It also makes a good
self- launching thermal soarer and if built really light could be used
indoors (although the V-Tronic is specifically designed for indoors!).
The business is owned by Kjell-Arne Fjelde who says of the indoor
version "The winters here in Norway are too dark, too cold, too
long and too windy to fly outside."
Here we concentrate on the Luna 400. This very simple white foam flying
wing uses a standard (or Speed) 400 sized electric motor, a 14-20 amp
speed controller and the recommended flight pack is anything from
8x700mAh, 8x800mAh to the brand new CP1300SCR cells from sanyo (these
weigh 2 grams more pr cell than the 800mAh cells, but give 60% more
duration).
Being a flying wing there is no fuselage, making it simple, fast and
cheap to build. It needs three radio channels (elevons and throttle) and
requires a mixer to mix the elevator and aileron to give elevons. Any
computer radio will provide this function. For non-computer radio users
a cheap electronic mixer can be purchased for around £10 from a model
shop.
Read on for building tips and the results of the flight tests.
What you get
Picture courtesy Flying Wings
The wings are very accurately cut from white foam using a CNC cutter and
come packed in their foam block outers. The surface is already pretty
smooth and requires only a very light sanding before covering.
Unfortunately I had already joined them (with copydex type contact
adhesive) before I thought to get my digi-cam out.
The elevons (ailevators?) are simple sheet balsa, the spar is a hollow
6mm carbon rod and all the necessary pushrods and horns are supplied as
are the corex winglets (not shown).
You need to supply two (preferably micro) servos, receiver, 400 size
motor, flight pack (I used a small and lightweight 7x500mAh cell pack),
a 20 amp speed controller, coloured covering tape (I also used glass
weave tape for added bounceability).
Building
Picture courtesy Flying Wings
At the time of the review the instructions were only available in
Norwegian so I rather "winged it" (pun intended) through the
construction process. Nothing here is cast in stone, if it looks right -
it is right!
Mark the positions for the spar and propeller cutout as shown.
As I mentioned before, the kit comes with a hollow rod 6mm carbon spar
but I managed to lose mine so here you can see an improvised thin
(approx 1.5mm) ply spar. Note the taper to save weight and to keep from
protruding from the slim wing's surface.
The balsa spar I made up seen lying along the right hand leading edge
was discarded in favour of the ply one.
Here you can see the spar sunk into a groove cut into the underside of
the wing. Also cut two reinforcing plates from 1/8th balsa as shown.
Picture courtesy Flying Wings
With the wing upside down position the servos in front of the spar
(equal distance from the centerline) and mark the position. Make sure
you allow enough servo lead to meet in the center for the receiver! When
happy cut out the rectangle for each servo.
Top view of the wing with the reinforcing plates glued on. Note the
small balsa ridges which will help to support the motor. All gluing of
foam to foam and foam to wood was done with contact adhesive. A thin
smear is applied to both surfaces to be glued and left for ten minutes
or so (or until clear) before bringing together. Wood to wood gluing was
done with cyano.
Next the elevons are top hinged using glass weave tape. Using a razor
plane or a sanding block the lower leading edge corner of the elevons
was shaved off so that full down movement could be achieved. A useful
tip here is to apply the tape to the top of the wing first and then lay
a thin spacer along the trailing edge before bringing the elevon up to
the tape. I used my steel rule for this. The elevon is then folded over
to lay flat on the top of the wing while the bottom strip of tape is
applied.
Top view of the wing with one servo installed. Note the shallow groove
to accommodate the servo lead. Apply some reinforcing tape to the
leading edges as shown.
Here you can see the lovely mess I had made of the kitchen!
Important safety tip: clean it all up before the wife gets home!
The position of the elevons doesn't seem to be critical other than it is
symmetrical. Here you can see how I positioned them. This contributes to
a unique and rather pretty plan form in flight.
View of the underside. OK so I went a little mad with the glass weave
tape - but each individual strip felt soooo light! Later I was to be
glad I had wrapped it up so well.
Another view of the underside. This time the two tie wraps used to hold
the motor in place are visible.
Now add the corex winglets using thin strips of - guess what - glass
weave tape top and bottom. This also provides an aerodynamic fillet to
reduce drag. (Right!)
Next, flip her over (ohh err Mr Grimsdale) and go colour crazy with the
colouring tape (available with your Luna here.
As well as helping with visual orientation in the air, this protects the
glass tape from UV sun damage. I left the underside alone.
Here you can see the position of the NiCad. It is simply stuck in place
with tape. The final position can be determined after a few test
flights.
The finished article complete with push rods (note they are at 90
degrees to the hinge-line at the expense of a tiny amount of drag) and
showing the slight hollow I carved to seat the battery pack in.
The receiver and speed controller are simply stuck on to the wing
between the motor and the battery with double sided tape. The receiver
aerial is carefully routed around the prop cutout and taped along the
trailing edge of one elevon. Any excess left over can either be left to
dangle in the breeze or threaded forwards and backwards through the
holes in the corex winglets. I prefer not to have too much dangling to
prevent stepping on the dangling aerial. A final strip of tape over the
electronics keeps any servo/power leads wires from fouling the
propeller.
Trimming, balancing and flying.
I took the setting up very seriously and did it while my tranny was on
charge! I lifted up the elevons by about 3mm at the trailing edge and
hooking my first and second fingers up and around either side of the
motor from underneath gave it a nice firm push forward at a slight
downward angle. Perfect. I would only recommend this method if you used
as much glass tape as I did though!
Transmitter charged and on, elevons programmed and flight pack charged
it was time for the off. Using the afore mentioned lobbing technique
(throttle OFF!) I launched it. The glide is so good that you have plenty
of time to get your hand to the throttle stick to give it some power and
off she goes. The climb rate is good and with maxi throws on the elevons
rolls are fast and easy. In fact it is easy to do a roll from the launch
BEFORE adding power!
Conclusion
This is a super fun model which takes around two to three hours to
construct (depending on how much tape you use and how fast you are). If
built for use as a slow fly or indoor model I would recommend that the
weight really be kept down - minimal glass tape (just wing join, elevon
hinges and leading edges), a 270 motor and tiny NiCad. In the
configuration I chose it is a superb general fun model, aerobatic and
capable of handling a medium breeze (more than my Twinstar). What's more
it is a very efficient glider with good penetration.
I have a couple of 1300 mAh NiMh packs that I use in my Pico Jet and I'm
looking forward to trying one of those out in the Luna.
With the small battery I used I was getting flights of six to seven
minutes with power on (but if you find a thermal this can easily be
extended). This is one for those summer days thermalling and without the
launch hassles of a regular glider. Due to the low investment in time
and money this is a real fun machine and if you do get it wrong it is
surprisingly bouncable. A must have model!
Prices
The following prices are in British Pounds (other currencies and postage
costs available on request).
| Luna standard version |
£23.00 |
| Luna EPP version (EPP LE) |
£27.00 |
| Tempra2 |
£23.00 |
| Coloured tape 3"wide, 55 Yards Long |
£4.50 |
| V-Tronic wing |
£12.00 |
P&P from Norway to the UK is around £12.00. (Packages over 5 wings
is around £5.00 more expensive)
Get further details and see some videos and pictures of the wings in
action at the Flying
Wings Website
Send Flying Wings an E-mail E-mail
©Gary Clemans-Gibbon
2 July 2001 All rights reserved
|
| Air
space is here
for anything you might like to write up of model flight interest. Tell
us about your particular branch of the hobby, d-i-y projects, review a
kit, or pass on your modelling hints and tips for instance. Have a go and get your work on the
web! |
|
