Report on Mikado's Logo 20 - by Bob Johnston
I have to admit it has taken me a
very long time to get around to finishing the Logo 20 review, I did start this
months ago when I was just finishing building the Logo but lots of other things
got in the way, part of the trouble is I have done so little flying this year
and it has been spread over a number of different models and when I have not
flown the Logo 20 for a while I forget just how very very good the model is,
then I get a chance to fly it for a flight or two, go home full of enthusiasm
ready to write about how wonderful it is, then it gets late and I'm too tired to
write anything, I think I'm getting old or maybe just too busy!
Anyway enough excuses, to give a little
detail on the model, it is a fully ball raced 20 to 24 cell model which has been
designed as an electric model from the outset (unlike some models which are
modified glow models) so a huge amount of thought has gone in to making the
model as light as possible with out compromising it's strength or rigidity.
The model can be set up with either mechanical cyclic, collective pitch mixing
via a rocking servo tray or the now popular 120 degree electronic CCPM and comes
with a nice aluminium swash plate as standard.
The model is of mainly plastic construction which I think is the best
choice as a lot of aluminium would add to the weight and cost, carbon would be
nice but would really add to the cost, might not be any stronger and would
probably do nothing for the model other than make it look pretty!
The canopy comes ready assembled and is constructed from ABS, a choice of
material that some might feel is a cheap option and not as durable as
Polypropolene which is used on a lot of 30 sized models these days. While
ABS is not as durable in a crash and can suffer from fatigue cracking due to
vibration after a while, it is a lot lighter than Polypropolene and should not
suffer too much vibration damage as there is so much less vibration in a
electric model. ABS can also
be painted and repaired a lot easier than Polypropolene can.
One thing to note is the boom is very
thin walled (to save weight) there is nothing wrong with this on this type of
model and in fact the tail is actually very good, better than a lot of glow
models even, but just be careful when adjusting the tail belt tension, don't do
this by gripping the tail gearbox or you risk the gearbox slipping around on the
boom by overriding the locating cut outs in the boom, once it does this then the
gearbox can ride up the boom and so slacken the belt off.
This happened to me and it took a while to work out what was happening
but all I did to fix it was relocate the gearbox and then drip a little thin
cyano between it and the boom to lock it in place.
I am sure when the time comes to get these parts apart the cyano won't
cause a big problem as it doesn't stick that well to ali.
I did the same to my Logo 10 as a pre-emptive measure, both the Logo 10
and 16 have the same tailbox as the Logo 20!
The model is about the same size as a 50
sized glow model such as the Raptor 50 and in fact takes the same size main
blades (60cm), you have the option of using standard or mini sized servo's, for
this size model I would definitely use standard sized servo's unless you really
want to save every tiny bit of weight and only plan to fly the model around
smoothly.
I used JR DS811 servo's on the CCPM set
up and a JR 8700G tail servo coupled with a CSM 540 gyro.
The rest of the flight pack consisted of a JR 649S PCM receiver and a JR
1100ma receiver nicad (I could of used a smaller lighter receiver battery but
wanted to make sure it could keep up with demand in extreme 3D situations)
I found the standard plastic tail blades
work just fine so have not changed these for carbon ones, the kit is supplied
without main blades, this is fine with me as it leaves you free to chose your
preferred make, I used 60cm NHP Razor's as these are a very low drag blade and
so great for electric models. One
small criticism is the model like the Logo 10 and 16 uses 3mm main blade bolts
and although this has not proved a problem as I have not managed to bend a blade
bolt I would be happier to see 4mm bolts used here.
I first flew the model on 20 cells and
the performance was good with plenty of power for conventional aerobatics and
some smooth 3D, the model is nice and stable, great for sports flying with this
set up but I found the head speed a little low for my liking, because of this
the model tends to pitch back in fast forward. This happens progressively as the
speed builds up and it not really noticeable until a fair speed is reached, I
must admit I did not try different pinion gears as I happened to have a couple
of 12 cell packs with me so I thought I would try the model on 24 cells.
The difference the 4 extra cells made was
huge and the model now had a better power to weight than a number of glow models
I have flown, with 24 cells there is very little the model can't do, full on 3D
including pirouetting loops, chaos etc are all possible. Obviously this amount
of power comes at a price and full on 3D kills my 2400ma nicads in about 5.30
minutes, you can carry on flat out for about 5 minutes and then just use the
last 30 seconds or so for climbing out for a auto or two once you notice the
power drop. I would think that 7 to
8 minutes should be easily achievable for sports flying when you are not putting
such a power demand on the motor.
I should say I am still far from a expert
when it comes to electric flight and there are others out there who am sure
could stretch the flight time a fair bit by careful section of the right pinion,
number of cells etc, but for now I am very happy with the performance.
Everyone seems to get a little obsessed with the flight time of electric
models, for me it is the quality of the flight that is way more important than
how long the model can be kept in the air, after all no one really gives a
thought for how long a glow model flies for one a tank so don't make flight
times the most important concern!
The model auto's very nicely with the NHP
60cm blades, the only thing worth noting is like any electric model when you hit
the throttle hold the tail stops instantly and completely, with a glow model you
normally have a little bit of tail drive because of clutch and auto unit drag so
you get a little bit of tail control, not much but enough to help keep the tail
straight at the end of the auto. You
don't get any of this with a electric model so if you are a little rough putting
on pitch at the bottom of the auto you can have the model yaw around a bit once
all forward speed is lost, be a little smoother on the pitch or if there is any
wind at all and you won't get this effect anyway.
A really nice option would be a
constantly driven tail to improve the aerobatic auto's (it really makes you
think how far electric heli's have come when you start talking about improving
it's aerobatic auto's)