I've always wanted to do a larger scale AS350 helicopter build because the AS350 Eurocopter is one of my favorite full size helos.
As luck would have it, I found a Roban Compactor 700 size Super Scale AS350 B3 on a good sale here in Canada and could not pass it by.
It was not exactly the color scheme I would have picked if I had a choice; but once it arrived and I started getting it all put together, I really started to like that black & cream with the copper and red pin-striping color scheme. This by the way is a real color scheme that was used by Wanaka Helicopters out of New Zealand.
For those in North America, you have
likely seen these 700 size Super Scale RC helicopter kits at Motion RC (the North American Roban dealer),
but they are manufactured overseas by a company called Roban Models. There
are several other Roban dealers throughout the world, so if you are
interested in them yet don't live in North America, it would not be a
bad idea to check for dealers that may be in your area to save a fair
amount on shipping and import fees.
things a little backwards here, let's start out with the interior first
and get that out of the way. The "Super Scale" of course refers to the
full scale interior these helicopters are sporting. The detail is not
Vario Helicopter quality by any stretch, but if you put a little extra
time into it to "spruce" things up and add some more scale items, it
comes out looking not half bad.
Above for example are a few of the little extras I added to this scale AS350.
First off the entire instrument pod was shiny black and looked pretty bad so I dulled the exterior to matte black with a medium grit ScotchBright pad.
I also painted the bezels around the gauges silver and a few buttons to make them "pop" a little more and added an LED RX battery monitor (circled in green) to the radio stack.
sure if I like it there, but it's super easy to see the monitor by just peaking inside the cockpit and it does add some LED & circuit board eye-candy to the cluster.
No question, if you have the time, you could really make a nice and detailed scale instrument cluster to put in this thing.
The instrument pod is made out of fiberglass so it would be easy to cut out the molded panel and install a highly detailed custom one with back-lit instruments, detailed buttons, CRT & LED monitor displays etc.
I actually just have my instrument pod bolted in from the bottom of the floor
so I can remove it should I ever decided to go the effort of making a customized cluster. Anyways,
at a distance the included instruments look pretty good; in other words
"good from far, but far from good" :-)
The kit comes with two cyclic sticks, but no collective sticks or tail rotor pedals, so I had to make them as well. I also made a couple fire extinguishers and made seat belts for all the seats.
I added seat backs to
the two front seats and then made little pockets for maps and air
sickness bags etc. I finished off the interior by gluing down beige
carpet (faux suede fabric that my wife had left over from a sewing
project). These customized little details likely added another 30 hours
or so of time to the build but they didn't cost me a dime and were a fun escape from a traditional RC helicopter build. I can also continue to add little details here and there over the years - that's another thing I really enjoy with scale RC helicopter builds.
By the way, the glue they used around the windows was a
very ugly & noticeable yellow. So I also had to take all the doors
off and carefully paint matching grey around the windows to hide the
ugly glue. Speaking of doors, they all work. The left rear door is a
large sliding door along with a smaller swinging front door. The right
door is a single large swinging door. The handles & door hinges look good, work very well, and door fitment/alignment to the body is near perfect. Fitting working doors on scale helicopters is a true PIA, so it was super nice that fiddly and insanely time consuming step has already been done for us.
Yes, the interior is begging for a full body pilot at minimum but I'm having a hard time with that. The actual scale of this AS350 is 1:6.6 so it's kind of an odd ball scale. 1:7th is on the small side, and 1:6th is a little too big... There are some amazing full body scale pilots out there but they are not cheap. Most I have found are well over $100, and it's pretty hard to justify to the wife how a (somewhat) grown man wants to spend $150 bucks on a doll (even I can't believe I would ever do such a thing).
Oh well, the search for a "cheap" pilot and perhaps some passengers continues. Barbie's teen sister Skipper may be a contender as she is the perfect size... Yep, you get some pretty strange looks from people in the doll isle in the toy department when you are measuring all the dolls with a tape measure. By the way, if anyone has found a good size and not overly expensive pilot for Roban's 700 size AS350's, I would very much like to know :-)
I have to thank a web visitor for letting me in on his 700 size Roban AS350 "Affordable Pilot" solution. As you can see, the GI Jane helicopter pilot is a a great option.
You can find them in the $30 dollar range on eBay.
She is 11" tall, but I did have to shorten her legs by about 1.5" so they would rest on the tail rotor pedals correctly. Once inside the heli however, you really can't notice her "newly shortened" legs so it's a workable solution. All the photos of her outside where taken before I performed leg surgery ;-)
As seen above, her hands very realistically grip the control sticks. The plastic is quite soft so it's easy to bend her thumbs back a little bit to slide her hands over the sticks and then she grips them quite well.
I'm also very glad I glued my seats in from under the floor with hot glue instead of epoxy or CA. I could not have fit her without removing the front seat so with the help of the heat gun on the back side of the floor to soften the glue, the seat came out super easy for pilot fitment. I had to custom make another set of 4-point seat belts for her as well and again, seat removal made that a 10 minute job.
Out of box, the components in the kit spread out do take up a fair amount of real-estate.The fuselage is huge when you first look at it.
likely the most impressive dimension on the Roban 700 super scale AS350
helicopter when you open the box is its width at 355mm. Pictures just
don't do that dimension justice.
The mechanics are of course custom designed for these 700 super scale bodies. They use a belt drive from the motor pinion to a larger belt gear, then one more stage of gear reduction to the main mast gear very similar to SAB's Goblin's. I could not find the final gear ratio listed anywhere in the instructions which is a pretty important specification to leave out! I had to manually do the calculation and it worked out to 14:1. Tensioning the toothed drive belt is easy by way of a sliding motor mount, but it's hard to get to the locking bolts afterwards. No you can't access them once the mechanics are in the fuselage so it's best to test fly before hand (more on that later)...
As you can see, the tail
boom actually sits near the bottom of the mechanics so that is
certainly a different departure from what most of us are used to. The frames by the
way are made from 2mm G10 fiberglass and have nice clean cut lines and
are of good quality. The entire set of mechanics come all assembled but
nothing is tight for the simple reason you have to take it all apart to
properly build it. It's an interesting design and is of course perfectly
suited to these large scale bodies with most of the mechanics sitting
up high in the helicopter & doghouse, just like the full size
You would think how big this thing is, there would be ample room, but the mechanical layout is actually fairly tight, as much of it sits up in the dog house so it has to remain fairly skinny. This is most apparent when looking at the servo and control linkages/bellcrank placement all being sandwiched between the frames as see in the photo below.
Notice the red arrows on all the servo wheels where the balls & links are mounted... I actually had to drill & tap those new locations for the balls. There is an excessive amount of mechanical gain due to the bell crank geometry from the servo pushrods up to the swashplate. I had to reduce that mechanical gain by moving the links in on the servo wheels because when I was configuring the flybarless system, I had to have overly low travel limit settings well outside the recommendations when they were mounted on the factory hole settings.
I figured this was a good compromise to the problem because it also means the servos won't experience as much load tension with the links closer in on the wheels. You can't see it well in the photo, but the
elevator arm doubles as the swashplate anti-rotation so no unsightly
anti-rotation bracket sticking like a sore thumb out the top of the dog
These kits don't come with any electronics so you have to pair your own which can blow the budget fairly quickly on a 12S powered 700 size helicopter. Even though you are not going be flying a big heavy scale AS350 helicopter like this that hard, you certainly don't want to cheap out on the electronics due the already high cost of the kit and no doubt, it's a heavy bugger at near 20 lbs, so it will be pulling some high rotor loads regardless.
didn't pile anything overly special in it, but I didn't go bottom line
either. Yes, I would have liked to put high voltage Futaba or Outrage brushless servos in
but I just didn't feel parting with $600 bucks for servos was necessary
so I stuck with decent bang for the buck coreless digital Align DS615's
on cyclic and a DS655 for the tail and they have been working great. I
already had a brand new Align 700MX 470 KV motor here I picked up at a
clearance sale a year or so ago so that was a no brainier, and I had a
brand new Castle HV ICE2 120 Amp ESC in the spares box as well.
All that was left was the FBL unit and receiver. The FBL unit was really no decision, I've been so happy with my Bavarian Demon 3X's so why mess with what works. Lastly I had a spare Spektrum AR8000 in the parts box so a little more money was saved there. I'm powering it all unregulated off a 2S 3000 mAh LiFe pack for a bullet proof onboard power source.
As you can
see in the above photo (circled in green), I've mounted that RX battery as far forward in the body to get the
CG somewhat in line. Like most scale builds, this thing is tail heavy
but I didn't have to use a single ounce of nose ballast.
All in all, I only spent about $500USD for the electronics but if I would have also had to get the motor, the ESC, and the receiver, the total cost for electronics alone would have topped out at over $1000USD! No question, electronics, even when you get fairly modest stuff adds up very fast on any larger RC helicopter - not just scale.
The Rotor Head
some of you may know, I'm not a fan of multi-bladed heads due to the
added BS, but there is no denying it looks great. The head uses solid
axles so there is no dampening per se, but the blade grips are plastic
and have a fair amount of flex as do the scale non-symmetrical rotor
blades. The head was all put together with thread locker, but two of the
blade grips were very tight & notchy feeling so I had to take them
off and investigate. The brass blade grip spacer washers on the two
grips were just a tad too thick and pre-loading the thrust bearings too
much. I had to wet stone them a tad thinner and that took care of over
The really cool thing with this head as you can see are the interestingly shaped DFC arms.
I'm no stranger to phasing multi bladed heads, but there is no phasing to worry about with this head.
The arms are already shaped to
account for the 90 degree gyroscopic precession phase angle of each
blade in relation to the swashplate. If blade phasing was all that was
keeping you away from multi-blade before, no worries in that respect
Getting back to those non-symmetrical scale blades, they are pretty decent looking and are full carbon blades. Balancing however is not great.
With my tri set of blades, two were perfectly balanced and the other was lighter by a fair amount (more than I would normally be happy with).
The only good thing is the one that was out was the light one so it was fairly easy to add some tape to it to bring it up to the other two. If it would have been the other way around, I would have had to add tape to the two balanced ones to bring them up to the heavy one.
In fact, this is
exactly what a friend of mine had to deal with on his Roban 700 Super
Scale Bell 429. He's also got 4 blades to balance and some of them are
out by the weight of a quarter - completely unacceptable! Roban has to
get this sorted out as I have read others with these same issues. In
fact, it almost seems so common, people see it as normal on these
models. Normal maybe, but certainly not acceptable when you are paying
this much money.
At the back end, there is a standard aluminum torque tube driven open right angle gear box with standard pitch slider mechanism and plastic tail blade grips.
What is different however are the umbrella gears both in the tail box and up front in the frame are full metal and not nylon like seen on most modern day RC helicopters.
I'm not 100% sure why this is, but the tail is working hard
on this thing as I will talk about later so that is the likely reason I
think. I made sure to apply an adequate amount of high pressure grease
to these little metal umbrella gears both up front and in the back.
I also had a sticking tail blade grip but this one was not due to bearing preload. Whoever assembled it got a little carried away with the thread locker and it had saturated the bearings so they were shot. Luckily they use the same size tail blade grip bearings as most 600 & 700 size helicopters so I had spares on hand.
All in all the build went fairly well and the instructions were adequate for an experienced builder. That said, for the money these things cost, there really should have been no such issues and I would have certainly been more upset if I paid full retail for this kit and had the same issues.
With the interior and mechanics out of the way let's "look" at the fuselage. I have to tell you, I was not overly impressed with the quality. The fiberglass work on the inside is pretty crude, the paint lines are not crisp & sharp, and the paint actually is fairly easily chipped. I have talked to others with Roban super scale helicopters and these are all common concerns.
Now I have to put all that in context. First off, the paint job/quality is at least an order of magnitude better than anything I could have pulled off (I'm a terrible painter). There are also plenty of worse pre-finished scale fuselages out there on the market, but I'm comparing this to
any of FunKey's fuselages. I still can't get over just how good FunKey
does scale bodies. The firberglass is near art work, and the paint is
damn near automotive quality - not so with Roban.
course all the little rivets do add a lot to the overall impact and
from just a few feet away, you can't even see the little paint imperfections. All in all, not bad...
Additionally nice as seen above, is all the plywood mounting spacers for mechanics attachment are all glued in place so there is no messing around with building custom spacing blocks
and taking several hours to perfectly align the mechanics inside the
fuselage. Just slide the mechanics in, a couple M3 bolts, and you're done! That alone is likely worth a few paint chips - LOL.
is separate from the main body and that helps further in the mechanical
install. It takes maybe 15 minutes to fit the mechanics once you have
done it a few times.
All in all, the mechanics fit very well into the fuselage and were in near perfect alignment. I did have to grind the tail rotor opening in the end of the tail boom a little lower with a Dremel sanding drum for pushrod/linkage clearance, but that was about it for fitment headaches. Certainly a welcome departure from what I'm used to on most scale builds.
Oh, the foam dampening doughnut that fits around the metal tail boom inside the body's boom was more or less useless.
It was so thin and flimsy, the mechanical boom
inside was "floating" more than being dampened. So I had to get a piece
of thicker foam rubber and make my own dampening boom doughnut. Not as pretty, but it works a hell of a lot better!
The dog house
dampening foam blocks are also pretty flimsy, but they work and they do
make it a little easier to slide the mechanics in & out.
The landing struts/skids are very nice and mount super easy to the body with hardware already in place (basically a 2 minute job). The kit also comes with the scale AS350 helicopter step plates and they are fairly well done. Once you stick some anti-skid tape over them, they look almost like the real deal. The other little external scale items that come with the kit are not that great.
The paint basically peels off the
antenna's the first time you flex them, and the cable cutters are made
from a very soft and brittle material. It would be well worth a persons
while to trace them out and build a set from 2.0 or 2.5 mm carbon sheet IMO. The two
step bars on the front of the tail boom are decent and strong.
Lastly, I really like how the entire scale interior section comes off the rest of the fuselage as it makes LiPo battery access so fast and simple. The interior section is held onto the body with very strong magnets. You also have the option to screw the interior section on, but I have found no need to as the magnets hold strong. Speaking of the batteries, both slide on plywood plates into compartments under the mechanics in the "bowels of the bird".
The instructions call for Velcro straps to hold both battery trays in place. This was a pain in the rear end I
found; so I just made a little plate out of carbon that keeps the trays
from sliding forward. I made a little easy to turn spindle (circled in green in the photo below) with an M3 bolt epoxied in the end to tighten this little anchor plate in place. This is working so much better than fiddling around with
one main concern I did have with this model, even before I got it was
the fact it's more or less meant to be flown off the bench with the
fuselage attached. Anyone who knows me or has seen my scale RC
helicopter page knows I would never-ever put a scale body over brand new
untested mechanics. I figured I would have to break my cardinal rule
with this scale build, but then I realized there is no reason I had to risk the fuse. I
could just build a test platform for it which is exactly what I did.
A friend of mine nick-named it the "Flintstone Flyer", and it's likely the ugliest thing I have ever flown in my life! Thing is, it was super easy to build and I was able to work out all the little bugs before subjecting the fuselage to the first wave of test flights.
I have to say, it flew very well off the bench with no real surprises - except one, the insanely long flight times. I was getting 14 minutes to a 75% discharged state. After downloading the ESC data, I could not believe how little current this thing was sipping. No question those three non-symmetrical rotor blades were responsible for some pretty efficient lift.
Head speed at this point was 1050 RPM and it
seemed fine. A full power climb-out however would cause the tail to lose
the torque battle of the huge drag created by the three bladed head.
Even if I held in full right tail before jamming the collective, the
heli would soon start pirouetting left. The tail rotor is only a two
blade, so that might have something to with it when used in conjunction
with a 3 bladed head with all that added drag. This is where I feel
having those metal tail gears is a good idea as the tail is working
I dialed the head speed up to 1100 to get the tail spinning faster and things got better; I was still getting about 14 minutes taking the packs down to 80%. I tried 1200 as well, and things got fairly lively, but not what I would like in scale and the rotor noise wasn't as nice as it was at 1100. Blade tracking was off a bit, but with three different colored tapes on the tips, it was fairly easy to set. I had to tweak a few settings on the Bavarian Demon, but other than that, the Flintstone Flyer was smooth as glass just like any large RC helicopter.
Time to fit the fuselage...
I initially set the 3 governed speeds in the Castle ICE2 to 1100 RPM, 1150 RPM, & 1200 RPM. Unfortunately, with all the extra weight of the fuselage, 1100 was just too slow. There was even more torque now off the main rotor hauling all that weight skyward and even a mild collective increase would induce a left yaw. 1150 was not much better. 1200 however is very acceptable I find.
Yes, if you perform an overly
aggressive climb-out, the tail may lose its battle, but if you fly true
scale style, it has no issues. So I reset my governed speeds to
1150,1200,1250. I mostly fly at 1200, but if I want to throw it around
just a little bit harder, I'll switch to 1250. One thing for sure is the
extra weight of the fuselage is certainly draining the LiPo's faster
now. At 1200 RPM, I'm getting a very safe 10 minutes going down to about
a 75% discharged state.
No question, the tail is working hard on this Roban Super Scale AS350 helicopter, so I wonder if a 3 bladed tail would work better or to increase the size of the tail rotor blades? You can't go any longer with the tail blades because the horizontal stabilizer fin is right there. So increasing cord width would be the only "size increase" option. If anyone with Roban 700 AS350 experience has tried this & it did in-fact improve tail authority, I would very much like to know.
March 2017 maintenance update including possible tail fix video below.
I had a couple flights today with the new asymmetrical tail blades I mentioned in the above video. Thoughts? Not overly impressed to be honest. No question, it's better, but not by leaps and bounds. Still, it was so bad before, anything is a welcome improvement and you can hear the tail is not working as hard, so I'm holding high hopes the gears last longer now. It flew great & I had a ball flying it again. Those are the main and only things that matter.
Also, I'm able to get grease to those front umbrella gears through the front of the mechanics using a long flat bladed screwdriver with a nice dollop of grease on the end. No need to cut an access hole in the side of the fuselage - phew! Think I will re-lube them every 10 flights or so from now on, when I do the tail rotor umbrellas.
Lastly, the Align DS655 tail servo gears were fine upon inspection. Reason for the grinding... there was almost no grease on them??? I lubed them up, along with the servo output shaft bearing and it became smooth as glass. First time I've run into that on an Align servo - weird.
I've been flying this scale AS350 helicopter now throughout the winter and into the spring and I can honestly say I'm super impressed. It looks and behaves so real and is just a pleasure to fly. I've had no mechanical hiccups at all and have more or less forgot about the initial issues I had during the build.
You do have to be careful with it however as it is a heavy
bugger and that along with the multi bladed head make it fairly easy to
get caught in your downwash (vortex ring state in the full size
world), and if that happens close to the ground, it could get really
ugly, really fast. It is also a bear to fly in the wind because of the poor tail authority. The video below shows just how smooth this big rascal
Would I get another Roban 700 Super Scale RC helicopter? Yes, but only when they go on sale (a good sale)! Paying full retail is too steep in my opinion considering some of the issues I and others have with them. Still, if you want a big scale RC helicopter with a full interior and don't want to pay near double for a Vario; Roban offers good value in that respect and there really is no denying just how great this thing looks and sounds in the air.
Paint and fibreglass quality are not near
what FunKey offers, but FK don't have the rivet details or the scale intriors so it's somewhat six
of one, half a dozen of the other depending on what you're after in a scale RC helicopter. If Roban however could get their
fiberglass and paint quality to approach FunKey's or FunKey could do a
700 size super scale - oh boy would they both be spectacular, jaw
dropping machines! The poor tail authority naturally rounds out the "misses" list.
I personally don't consider this super scale AS350 helicopter a good "first" scale build. I actually would have had fair amount of trouble with it if I hadn't already built some other large FunKey scale birds first.
That said, out of the many super scale helicopter models that Roban offers, the AS350 is definitely one of the easier ones to start with.
Battery access is super easy, there are no complicated angled tail
boom drives to deal with, there are only 3 main blades to contend with
along with a conventional two bladed tail, and it's fairly easy to put
The other nice thing with having only three blades is you can still fold them all back into a blade holder and don't have to remove them for transport.
That personally has been one of the things I didn't care for with most multi bladed heads, so I was pretty happy when I realized I could still leave all the blades on as I heaved this heavyweight behemoth into the back of the vehicle.
To finish off of this Roban Super Scale AS350 helicopter review, here are two great full size AS350 Eurocopter videos. One warning however; after watching, you'll likely want to build a scale AS350 helicopter of your very own ;-) Enjoy!