Hi all,
Tests and success with a fan
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Recapitulation
Fitting a propeller to a model without a proper fuselage
has its problems, which some solve by fitting a pusher, as
it then is a little less prone to landing damage.
If you fit a tractor folder you need a long nose, so that
the blades fold properly, and so on.
I got an early Aveox 1114/4Y (now discontinued) and the first
test run, after the problems with it running backwards were solved,
it threw a blade on the little grey Graupner I attached - and the
shaft bent about 45 degrees. I straightened it as well as I could
and henceforth used it for belt drives.
My other 1114/4Y I took special care of and decided early that
it would fit very well to a small fan, which a year later was bought
in the UK. A test with eight cells on my trusted powered Zagi HTL
testbed ('Dash 01') and this little fan and a 400 was not much fun,
and bench tests with the fan combined with the Aveox wasn't that exciting!
So I decided that I'll get a bigger fan (also Graupner) and mount
the 1114/4Y in that, and them both on the Dash 01. Well, flew,
but very short endurance, and I don't dare to mount a bigger, heavier
pack on a Zagi, so I built my Mongo Jr kit that had been lying about in
the garage - that should be big enough, and I decided to use ten RC2000
cells, to get a bit more ommph!
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Now we get to today, after a first test flight with erratic power,
but excellent results a week ago. It eventually glided, powerless to
its doom - nothing worked, but just the fan pod got banged about.
Sp what was the matter: Was it a faulty Aveox ESC, a noisy enviroment
or what? After repair of the fan pod, now retained in the EPP by a
single loop of copper wire (approx. .8 mm, 0.03"). So in a crash nothing,
hopefully, will be crushed!
So first the bad news: neither another (oldish) ESC helped, with separate
battery, nor switching to a full length antenna on the tx. So it will be
a PCM reciever next time!
For the good news: The combination of a Graupner fan and an Aveox 1114/4Y
is a marriage made in heaven, these two, plus a Mongo Jr and a ten cell
RC2000 pack is near ideal. More impressive, yet innoxious, is hard to find!
I'll use this huge flying wing (over 1000 sq. in.) as a teaching tool,
no doubt!
This Mongo Combo isn't the hottest plane I've flown, far from it, but my,
what a delight! Tried loops, excellent! Tried stalls: Impossible power on!
Tried sharp turns: Effortless! I didn't try inverted flight, nor did I
try rolls, but whatever else I tried it shrugged off like it was nothing -
and this was done on a day when the waves were more foam than waves, say
20- 25 konot winds! The glide ratio, against the wind, wasn't impressive -
more like a carrier aircraft than anything else - heavy landing, but
definitely down, power off; last landing done with fan idling - no
difference!
Effective flight time was 450 seconds, aka 7.5 minutes,
and that was with the motor running full speed 90% of the time! It
climbed, against the wind, seemingly for ever. As I feared control
problems I took it easy after the aircraft passed 300 ft, I can't say
how high it will go, eventually!
Each time I had problems the rx amtenna was pointing away from me - using
a normal antenna improved matters a bit, compared to the duckie, which possibly
wasn't screwed in tight. But not altogether!
Next try will be with a dual conversion rx!
As the wind was high, turbulence was high as well, but it didn't provoke
much reaction from the Mongo Jr, just some shaking of the wings. In a full gale,
this was a bit less, a gyro could be useful! Speed was impressive, at least
60 knots!
In short, an amazingly userfriendly fan-powered aircraft! Endurance was in the
7-8 minutes range, which gives an average of 15A, which to me sounds quite
alright! I am sure I will have a lot of fun with this one - pity it is a bit too
big for the car! But it can be crammed in, with some effort from the driver's
side :-)! Let's put it like this, view isn't totally unrestricted :-)!
I'll use an antenna trailing behind the aircraft next time, as its rx range
seems to be influenced by the Cf rods in the wing! Or any better ideas?
Thanks Bill Swingle, BASH, Mr Iljescu (who carried the Mongo Jr across
the Atlantic), Tom Rust (who took care of it all) and you guys at Graupner
and Aveox that made this flying delight possible!
With a 600 the endurance would be slightly shorter, but that would be
the only difference!
No photos as yet!
Yours,
Tord,
Sweden
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Tord S. Eriksson, Ovralidsg.25:5, S-422 47 Hisings Backa, Sweden
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