Un-packing and assembly of the ultra-micro

Opening the box was exactly what I expected – the little model safely in the foam, with a spare propeller, the landing gear and manual securely taped in place too.

Interestingly, this plane looks even smaller “in the flesh” than it does on the Parkzone web site. That said, I’m not at all worried, I have big planes and this was a purchase for a small electric RC plane to fly at my local park – so fits the bill nicely!

I found the lipo battery half-charged out of the box (this prolongs the life of the battery when in long term storage), and as a result it took only 15 minutes to charge fully in the included charger (with 4x AA batteries conveniently in the box as well).

After giving a quick top-up charge of my Spektrum DX7 transmitter and binding it to the plane I was ready to set the appropriate throw rates (this model does not come with a transmitter, you need to provide your own DSM2 compatible one).

One thing you’ll notice is that the control surfaces are very generously sized – so this model is definitely equipped to do some pretty impressive aerobatics.

Although I have a few years’ experience flying low wing models, I haven’t really done a lot with 3D planes – as a result, I decided to conservatively set the control surface throws – knowing they can always be moved out in the future.

As a result, the low rates were set as 60% movement, with 35% exponential for all surfaces (ailerons, elevators and rudder).

I left the high rates at 100% movement, and with 45% exponential for all surfaces.

The undercarriage also clips neatly into the fuselage, and although feels quite sturdy, given my first landing would be on grass thought it best to detach them (a blade of grass is about the same height as the undercarriage – so this undercarriage is purely for cement/indoor landings only!)

First flight

My first pleasure I have to admit was being able to drive only a short distance to the local park, given this rc electric plane is so small! (It’s not called an ultra micro for nothing!).

I found a quiet soccer field, and in winds of only about 5 knots, throttled up to 50% and gave it a gentle throw after checking to ensure I was on low rates. Impressively, the plane did not require any trim at all – it flew perfectly, straight away.

After taking it up to about 30 feet, I did about five circuits to get a feel for the model. Even at 60% throw, I noticed the ailerons were still very responsive (with nice fast rolls) – so much so that in hindsight I’d probably drop the throws to 50% for a first flight.

Throttling up to 100% demonstrates what this parkzone ultra micro is capable of – certainly plenty of vertical performance – it’s a fast little monster actually.

One thing I did notice, although I was only in light winds, was that when it gusted the model certainly does tend to jerk around. At a guess the wind probably got up to about 8 knots – so certainly quite light, but enough to knock the little model off course.

The motor provides adequate power to charge through the gusts, and given I was at a safe height, just needed to re-orient the Sukhoi back onto its path. I suspect if I was running closer to 100% throttle (most of the time it flew around at 50% power) the gust would have had a less noticeable impact.

The only slight negative I found was that even the slightly higher capacity 150mAh battery (many parkzone ultra micro’s come with a 130mAh lipo) only gave me a flight time of about 8 minutes. I noticed that in the last two minutes of this, the top range of the throttle did tend to drop right off too (maximum appeared to fall to about 60%). For the flying I was doing this didn’t really matter, but I could imagine a more experienced pilot doing 3D manouvers may feel the flight duration is a little on the short side for an electric model.

One other side note worth a mention is that I placed battery at the most forward location to shift the centre of gravity as forward as possible. In actual fact, it appears this is pretty much the desired CofG setting as stated in the manual (3cm from the leading edge of the wing), so really it is actually quite hard to get to a very “nose heavy” settting. Even though the Parkzone promo video’s suggest the battery can be moved “up and down” to the pilot’s liking, it really should be re-worded as moving “down” to really just add more weight to the tail as the pilot gains more experience.

I know this is splitting hairs, but essentially you’re not really able to make this model more nose heavy should you wish to. Although for most hobbyists I don’t think you’ll need to do this either.

Distance wise, I flew this model up to about 100m away from me. The receiver worked perfectly and I didn’t receive any interference or loss of control. Any further than this distance and I found I’d start to lose sight of the direction of the model given its size. As a result, the space this model needs is genuinely quite small. An area the size of two basketball courts is really quite perfect.

Final comments

Horizon Hobbies claim it’s a model for intermediate to advanced pilots, and I tend to agree if you want to get the most out of it – however it is not that difficult to fly – just set the low rates to about 50% and you’ll absolutely love this model. If you’re comfortable with low-winged planes, I think you’ll find you’ll be OK with this Parkzone Sukhoi 26 xp too.

Grab yourself an extra battery and you’ll have a heap of fun – definitely the perfect model for taking a break from the office during your lunch hour!

I recently went out and purchased the Parkzone P51D to have a fun semi-scale foamie for those times where you just need to get out and back from the flying field in a short space of time, and want a super-fast model that you don’t mind bashing around a bit.

As many forum posters have noted, this is a fabulous looking foamie, however doesn’t pack quite the punch that one would hope for with a Mustang.

The main challenge I have found is that on days with wind more than 5kts this RC electric model does tend to look a bit sluggish in the air when travelling upwind.

There are really only two components you need to change out to get this plane absolutely roaring around the field, in addition to checking your battery is up for the task.

a) Upgrading the propeller.

The propeller that comes with this Parkzone P51 is a 9×6, and with a medium-low revving motor of 960kV means the top speed is somewhat limited.

So the best thing to do is add more “bite” to the prop – I swapped it with a spare Parkzone T-28′s prop (9 x 7.5) to give it theoretically 25% more speed (before aerodynamic inefficiencies etc are introduced).

b) Changing the ESC

This little model only comes with an 18A ESC, and when run on my watt-meter at wide open throttle (WOT), reads about 15A with the default prop. As a result, making the prop 25% bigger will increase the amps by approx 25%, with a likely scenario that I could damange the ESC, resulting in radio failure and a downed-model.

So I changed up to a 25A ESC to allow for this increased load on the controller.

c) Check your battery

The battery which came with my model was a 1300mAh 15C (which reportedly bursts to 20C). On WOT we are pretty much reaching the maximum discharge level for this battery (see our other article here on understanding battery C rating).

As a result, I purchased a 1500mAh 20C battery which is used for performance flying, and the 1300mAh battery is thus left for less throttle-intensive flights with this model, and for my other parkflyers.

How does it run?

The new prop pulls just on 19.5A when on WOT, which is well within the performance limits of the 25A ESC, to the point that it generally comes down cool after a typical flight.

The added weight of the 1500mAh battery is negligible and hasn’t noticabally impacted performance.

And most importantly, this plane flies like a Mustang now! It’s quick, responsive and really looks the part down at the flying field!

This upgrade is highly recommended, you’ll have a ball!

Unpacking & preparation

After receiving the Eurostar from Alex at ParkHobbies.com, I was pleased to find all parts neatly packed in sealed plastic bags and grouped for each section.

On this particular model, the aileron, elevator and rudder control surfaces were already glued into their respective positions which was a bonus, as the instructions showed this had to be done.

The surfaces were too stiff so I used a fine dremel cutting wheel held in my fingers and just dragged it through a few times on both sides of the hinges by hand. This removed the excess epoxy glue and allowed them to move freely.

The main wing is packaged as one piece not requiring two halves to be glued together like some other models which is a bonus.

Assembly

The engine mounting box is made from pre-cut ply, and care is needed before gluing together to see that it is assembled in the correct manner to give the motor a small amount of right and down thrust.

To fit the wing I deepened the hole at the front a small amount to allow the wing to sit down in place in the fuesalage and align the screw holes at the rear.

I like to test the ailerons and adjust by plugging into a spare receiver using a 4.8 volt flight battery for power coupled through an on off switch before fitting the wing. I once destroyed a small receiver by trying to plug the flight battery straight onto the battery pins on the receiver. The switch eliminates that risk.

Don’t forget to use the small pieces of plastic hose or fuel line for keepers on the aileron clevises to stop them from coming unclipped. (Further info on how to do this here).

When fitting the tailplane, I had to remove a small amount of balsa at the rear of the fuesalage to allow the elevator to move up and down freely. This and checking the rudder fit was all done along with measuring from the main wing to get the horizontal stabilizer square before glueing.

Before mounting the rudder and elevator servos, check the length of all pushrods. It may be better to mount the rudder servo the opposite way around to that shown in the instructions to better suit the supplied rudder and nose wheel pushrods. After these parts were all completed, I then mounted the motor mount to the firewall using 4’ of my own 3mm bolts, as there were already bling nuts in the firewall. This was a bit fiddly or the mount can be glued as per the instructions.

The canopy was trimmed and fitted with 4 screws and likewise the cowl after a test fit with the motor to make sure of correct clearance for prop and spinner.

First Flight

I used one of my Corona 2.4 gig receivers and mounted it under the canopy after cutting a small hole in the black film to bring the plugs through. By mounting the receiver in this position, I can see the red neon indicator to confirm the receiver is bound ok. After a final test and check of C of G using a 1300MA 3 cell lipo and motor and equipment as per Alex’s recommendation, she was ready for the maiden flight.

Unfortunately, several days passed by before suitable weather was available for the test flight.

Finally late one afternoon, the wind dropped a bit, so down to one of our local flying spots and away we went. After an easy take off, a couple of clicks of aileron and elevator trim had her flying straight and level, hands and feet off, no problems. I climbed up high, levelled out, eased the power back to off then kept checking back on the elevator for a stall. I was surprised to see the nose drop gently until she picked up speed then stalled again. No serious loss of height or tip stall like some of my other models. With the power back onto a bit over half throttle, she put on a good turn of speed and rolls or loops weren’t a problem.

The colour scheme of the Eurostar with stars and stripes looks great in the air and on the ground.

I was flying on dual rates with 70% +-35 expo which I usually use on my models of this size and she was precise,and easy to control. I  flicked the elevator up to 100% and chose to use this on landing which enabled me to hold her off better and make a perfect landing followed by a turn and taxi back to my feet.

All in all, the little Eurostar from Alex at  Parkhobbies.com was a pleasure to build and fly, and it certainly catches the eye at your local field.

If you’re a beginner to RC planes, tt’s really helpful to find a good RC model airplane club at the beginning of your interest in this hobby.

Here’s a list of some main associations around the world – on their sites you will find a list of local clubs:

Model Aircraft Association of Australia

Australian Electric Flight Association

British Model Flying Association

Academy of Model Aeronautics (USA)

Model Aeronautics Council of Ireland

Chatting with people who share a common interest in model aircraft will ensure you have a great afternoon! Further to this, you’ll get some very good localised tips alongside my more “macro” suggestions listed here.

RC Transmitters

One of the first things you need to do, before you start learning to fly is to decide what “mode” of transmitter you should learn on.

There’s no right or wrong, but typically the popular modes are 1 and 2. With Mode 1 transmitters, the throttle is on the right joystick. With Mode 2 transmitters, the throttle is on the left joystick. As a very general observation, North American rc pilots tend to be Mode 2 operators in the majority, while in Europe and Australia, Mode 1 pilots seem to be more common.

Rather than deciding this Mode for yourself, hunt down an instructor at your local club and find out what mode they are – that way you’ve got someone who can train you! Personally I use a Spektrum DX7 mode 1 transmitter, and would thoroughly recommend either this or the DX6i for any newcomers.

The second reason it is good to visit your local club early on is that you will more often than not have a reasonable chance of securing some good quality second-hand equipment, saving you money up front.

The final reason is plane selection – again you may be able to find a decent second hand “trainer”, but otherwise, will get some handy local advice for finding the best deal on your new airplane and radio equipment.

Perfect radio for beginners - the Spektrum DX6i

Fresh in the knowledge of the “mode” of transmitter you wish to learn on (from part one of this article series), you are now in a position to source yourself a good simulator to practice on. The key reason it’s helpful to learn on a simulator is that you’ll get good “directional co-ordination” – remember, when your plane is coming at you, leaning right on the rudder will make the plane look like it is going left!

Also you’ll be able to practice landings without having to do lots of repairs. Personally I crashed on the simulator approx 30 times before I successfully landed, so don’t be put off if it takes you a while to get the hang of RC flying, it is a skill and takes time to consistently get right. (But the simulator is heaps of fun!)

Radio Controlled Aircraft Simulators

There’s a free package called FMS, but you’ll need to be handy with computers to connect your transmitter to the USB port. Further to this, the graphics and realism are not brilliant. It’s good for free, but there are better ones around if you have the money for them.

RealFlight G5 and Phoenix

Definitely two of the better ones, both have great graphics, flight instruction lessons, and you can turn on plenty of environmental factors such as wind gusts to increase the realism and the challenge. Both are highly recommended. They also come bundled with controllers in either Mode 1 or Mode 2, so no mucking around with your computer, just plug them in, install the software and you’re ready to learn!

RealFlight has the added bonus of a healthy discussion board, where users can upload their own aircraft. You need to check the ratings to ensure the models contributed are realistic, however there are some lovely examples available (generally for free too!). Phoenix can be found here.

Clearview is another airplane simulator which is reasonably popular in the radio control community – it’s a great option to consider if funds are tight but you’d like something a little more advanced than FMS.

I’ll continue with the next few steps in my next post!

Realflight G5 - perfect simulator for beginners to RC planes

]]> http://www.parkhobbies.com/2010/04/28/rc-planes-for-beginners-tip-two/feed/ 110 http://www.parkhobbies.com/2010/04/27/rc-planes-for-beginners-tip-three/ http://www.parkhobbies.com/2010/04/27/rc-planes-for-beginners-tip-three/#comments Tue, 27 Apr 2010 10:38:05 +0000 Alexander http://www.parkhobbies.com/?p=597 The Parkzone Radian, a great first RC plane

Although it may seem strange that I’m about to recommend this, given we sell parkflyer electric rc models on this site, I do encourage you to start with a larger plane as your first, ideally with at least a 55″ wingspan to begin with. The parkzone Radian is a great way to start (even though it’s a glider it is a good flyer), as is the eflite Apprentice.

My reason is simple – the bigger the better. They’re more stable in the air (less susceptible to being knocked around in wind gusts) and are generally more sturdy as a result of components being bigger. It is definitely possible to start with a simple high wing “parkie”, such as a Cessna 172, however they’re a bit trickier to get a handle of, purely because they are smaller, and you don’t really want to crash a nice model do you?

The eflite Apprentice is a good example of an electric “trainer”. Trainers are built specifically for learner pilots, and they have wide wings mounted above the fuselage, making them fly slowly and steadily. You’ll also find you can re-use many of the components with your park flyer, particularly the battery charger as these aren’t particularly cheap.

If you’re lucky, your club will have a “club trainer” that you will be able to use – a great way to cost effectively enter the hobby!

There’s no problem with your second plane being an 40″ wing span electric model, but ideally for your first, get a bigger one which you’ll fly only at your club.

The Parkzone Radian - perfect RC plane for beginners to learn on

Wow – so many things to do before we’ve even flown! OK, so here is where it all comes together. Tee up a time with your instructor and meet him/her at your flying field. They’ll do a pre-flight inspection of your plane, and then take it to the skies and trim it out for you.

After this, your instructor will be able to “buddy” up with you – most modern transmitters are able to be “buddied” up with another transmitter of the same brand with a simple lead. This way they will be able to hand control to you so you can learn to fly, and then easily take control back with the flick of a switch if you run into a little trouble.

After a few weeks and a bit more practice on the simulator, you’ll be ready to fly solo! You may need to pass a test (such as your “Bronze Wings” in Australia with the MAAA) before you are properly insured, and your instructor will be there to help you out here too, quite possibly being the person who will be testing you as well.

Your local RC flying field - plenty of people to talk with and airplanes to look at

As with your first trainer, although not absolutely necessary, try starting with a high winged plane, so you can ease into the smaller size of parkflyers. You can definitely have a little more choice about what you’d like to purchase, a semi-scale ARF (“Almost Ready to Fly”)  Cessna 172 might take your fancy for example, and they look great down at the park.

If you do wish to go for a low winged plane, do try to get a slower one (not an Edge or an Extra). I’ve regularly fly my EuroStar SL and it’s a great first low-wing park flyer to try out, as is the RC Cirrus SR-22. You’ll notice low winged planes don’t tend to “right themselves” like high winged RC planes do – so just be aware you’ll need to flick the ailerons in the opposite direction to your turn to help you straighten the plane back out.

Before I begin – credit for a lot of my learning must go to the wattflyer forums specialising in providing great info on radio controlled planes and in particular this thread http://www.wattflyer.com/forums/showthread.php?t=24238 , it really is a great place to start if you are new to the world of electrics and I encourage you to take a look at it.

There are really just four steps you need to follow to select the right bits for your rc plane if you wish to do this yourself. A bit of research IS required, but if you follow the rules I’ve set below you’ll find it makes it very easy to get the right setup for your electric parkflyer.

1. How much power is required?

A good rule of thumb to follow is an RC model trainer needs approx 50-100W per pound, a sporty model needs approx 100-150W per pound, with more powerful 3D models requiring 150W to 200W per pound (and more!).

Once you have this performance figure, add another 50%. My reason is that anywhere between 10% and 30% efficiency appears to be lost throughout all the components in the system, so this helps ensure you won’t have an underpowered model.

Brushless motors tend to run anywhere between 80% and 95% efficiency, there’s resistance within the lipo battery, the ESC (electronic speed controller), each connection, cables and (in)efficiency associated with the propeller too.

Using a newly-purchased Decathlon parkflyer, I estimated it would weigh approx 1.0kg (2¼ pounds) ready to fly with a generously sized battery in it, and I selected 110W per pound for “sporty” performance. The power system thus needed to provide 248W to the prop (110W x 2.25lb). Adding 50% this number reaches a system target of 372W.

So – I was looking for a system that pulled around 370W on full throttle, delivering a useable 260W (with 30% efficiency loss).

2. Pick the battery

Take a look through your battery choices, which will help you determine what sort of ESC you will need. In the case of the Decathlon:

1 cell LiPo: 370W divided by 3.7V = 100A required current

2 cell LiPo: 370W divided by 7.4V = 50A required current

3 cell LiPo: 370W divided by 11.1V = 33A required current

4 cell LiPo: 370W divided by 14.8V = 25A required current

So a 3 cell or 4 cell LiPo battery seems like the right choice for this electric rc plane – that way flight times can remain reasonable, and component costs stay down too (a useful rule of thumb – higher amps cost bigger dollars!). I ended up selecting a Zippy Flightmax 4400mAh 3S battery – on full throttle I predicted the model would fly for 8 minutes (4.4Ah / 33A x 60 to put in mins).

Zippy FightMax LiPo Battery

Please find the next post where this article is continued…

In this final section you’re shown how to select the correct RC plane speed controller (ESC) for your park flyer, in addition to finding an appropriate brushless motor and propeller, as well as the actual results from our R/C Decathlon.

3. Select the RC Plane Speed Controller

This step is actually pretty easy – just determine how many amps your power your system will require and then get an ESC that can handle this.

The Decathlon’s system was estimated to run at up to 33A (max) on a 3S battery (look at the table from part one of this post for a 3-cell battery). Thus I picked an ESC that will support 40A, and would burst to 55A for short periods – allowing a wide safety margin for the requirements of my electronics and a good amount of power for this parkflyer.

See, I told you this step was easy!

Turnigy 40A Speed Controller

4. Finally, select the motor and prop

There are plenty to choose from – so it’s best to just read up on some reviews before making your final decision. www.bungymania.com is a good place to access a wide library of test results from different motor/prop combo’s.

For the radio controlled Decathlon, I selected the Turnigy 3536C motor, and matched it with a 10×7 wooden prop, again my research suggested this combo would draw about 30A at full power, and the motor was able to take the required 3S battery (11.1V).

Once I had everything, I secured the motor, ESC and lipo battery in my ARF (almost ready to fly) model kit and got ready to run some tests. I completed it with a Spektrum AR500 full range receiver, and some Parkzone and HXT servo’s I had on hand.

Turnigy 3536C 1100kV Motor - a great fit for larger parkflyers

So how does it perform?

At full throttle my watt meter reads 34A – so pretty in line with what I wanted, and thus I am really satisfied with this result for this RC model plane. Notice even after increasing the required power by 50% I found the motor was a perfect fit, in line with the Amps expected.

When flying the model, there is a good amount of power available but not excessive, it takes off steadily at 2/3 throttle, and it will fly around for about 15 minutes at just over half throttle thanks to the big 4400mAh battery.

The park flyer runs for about 9 minutes when I push the power a little more, and comes down with, at most, a warm battery, with each cell hovering around the 3.80V mark. The electronic speed controller comes down cool as well.

I’ve handed the controls around a little at the MARCS club in Melbourne, Australia, and the comments I have received are consistently positive – not excessively powerful but certainly with enough “oomph” when needed. It certainly manages spins, rolls and loops easily, so very much in line with the sportiness you would expect of a Decathlon.

So there you have it – four steps to pick the correct electronics system for your plane. I hope you’ve found this useful – and feel free to add any comments / questions below that you may have on this methodology.

There are some wonderful details and smart design elements in this RC model plane, which we’re sure you’ll love. It comes “almost ready to fly” – the built-up balsa wings connect to the aircraft via aluminium formers, and they can be released easily for transport and storage using a rubber band / hook combination.

There are balsa winglets integrated completely into the main wings, and in addition the pre-formed wheel pants, and the bolt-in canopy with shaded windows all add further to the semi scale realism of this radio controlled Cirrus while making it really convenient down at the flying field.

With a 36.6″ wingspan this is a really practical parkflyer sized model to have, and coupled with a 180W electric motor it zips around the park.

You’ll notice in the photo’s there’s heaps of space to locate your rudder and elevator servo’s, in addition to a LiPo battery and receiver, so you won’t need to worry about having to have little fingers for this one!

It’s lovely to fly as well – and is well suited to the hobbyist who is onto their 3rd model, with its straight forward and predictable handling. The separate servo’s for each aileron give direct control for more responsive handling and aerobatics. Being an electric ARF plane this R/C Cirrus is pretty quick to build too, and you’ll probably only need an evening or two to have it ready to fly.

We’re sure you’re going to love this one!

Sporting a 112cm wingspan, this ARF (almost ready to fly) balsa/ply model features the classic Cessna lines to replicate its unmistakable appearance on the flying field. Complete with coloured wheel pants, a shrouded undercarriage and pre-formed cowl it faithfully represents the original 172.

Inside the Cessna’s fuselage you’ll find there is plenty of room to place your servo’s, speed controller and battery, and direct top-down access via the bolt-on wing makes it simple to connect up the ailerons and conduct battery swaps.

To complete the realism of this model you may also choose to place a pilot / co-pilot into the cockpit as well, taking advantage of the space available, although we didn’t at the time of taking these photos.

One of the things I liked about this RC air plane are the servo connections to the rudder and ailerons. In many park flyers, due to space requirements, the linkages are often visible at the rear of the tailplane. Not with this Cessna 172. If you look very carefully, you’ll see the servo horns are present on the rudder and stabiliser, however are underneath and very well hidden from view.

It’s a great element of the design and really helps make this parkflyer look like a real scale Cessna.

There’s a couple of other elements in this 172 parkflyer which are worth mentioning as well:

Anyway, being a high wing it’s fairly straight-forward to fly, so even if you’re a beginner to the word of radio controlled planes I think you’ll enjoy this one.

ps: You may notice some construction in the background , the location is Albert Park, Melbourne, and they are assembling the stands for the 2010 Australian Grand Prix… anyway on to the photos…

An iconic aircraft, with it’s curved rudder and wide fuselage – it’s often seen skipping over the lakes or being used as a utility plane in Canada and North America, and this model is a great semi-scale representation, conveniently Almost Ready to Fly.

Unpacking the box you’ll find every component of the model plane wrapped in clear plastic bags for protection. The seven page manual takes you through the 24 steps for final assembly, each including a photo or drawing of the park flyer for clarity.

This radio controlled DHC-2 will take two to three evenings for you to complete, including adding your desired electronic components and running final bench tests.

To ensure glue sets well on your radio controlled Beaver, we recommend you use PVA on the key fittings (eg connecting the wings together, building the motor mount) and leave these overnight. PVA is great for wood – it provides a strong and clear bond and your patience is always rewarded with a well-built and unrushed aircraft at the end.

The TowerPro 2409-18 bundle which includes a 25A ESC is well suited to this aircraft (available from HobbyKing.com), and to this add an APC 9×6 prop and 3S 1500mAh battery. At full throttle our tests showed this combination will draw about 17A of current, so well within the required spec’s of this equipment. Three HXT900 servo’s were used for the ailerons, rudder and elevator, and as per usual we added a Spektrum AR500 receiver to go with our DX7 transmitter.

We had to wait till early last Sunday morning before the Beaver could be flown, but with almost no wind, plenty of sun this was the best morning one could ask for on our maiden flight.

Although the manual states the centre of gravity is 50mm to 55mm distance from the leading edges of the wing, it is always better to shift it forward a litle more for the first flight - and then gradually move the battery back over progressive flights until you reach the best setting for your particular build. We set it to 40mm, and after a final radio check and once-over of all the critical connections, the Beaver was ready for its first R/C flight!

Positioning the airplane on the runway, we gradually throttled up and were pleased to find this electric Beaver takes off at around 2/3rds throttle, so I then took it up nice and high to check the trims. Nothing bad to report here, a few clicks of down elevator and it settled in nicely.

After a few circuits we throttled up to full, and pulled up on the elevator. Given its light weight, the DHC2 was able to go vertical for approx 4 seconds before losing air speed (and it covers a lot of height in that time!).

It handles spins well, ours settled out nicely after letting go of the joysticks. Loops and inverted flight are no problem either for this model.

Something to be aware of is this RC plane really does want to stay up in the air, to the point you really do need to drop the throttle right back quite early on the final turn, and then pretty much glide it in to a landing.

The steerable tail wheel is quite handy for ground handling, and the large front wheels will help you easily navigate some of the larger bumps if you’ve got a dirt/grass runway.

This plane will happily track around for 10 mins plus on a gentle flight, and if you push it harder, will go for 6-7 minutes without any problems of discharging the battery too deep if you’re running a 1500mAh unit.

All in all, a very pleasing aircraft to build and command! Highly recommended, this park flyer Beaver looks great and flies great, so get your hands on one before they’re all sold out!.

Some final specs of the model:

• 102cm wingspan, 4 channels radio controlled park flyer
• balsa / ply construction
• vacuum formed cowl and traditional Beaver rudder shape for scale looks
• fully integrated & tapered winglets on main wings
• pre-formed tinted windscreen
• tough landing gear – built to take a few hard landings
• main wing is easily unbolts for simple storage, transport and battery access
• clear side windows
• heaps of space internally for servo’s, battery placement etc
• elevator/rudder pushrod guides are pre-installed for easy setup
• traditional artwork for iconic “Beaver” appearance
• wing support spars included
• white wheel leg covers included
• limited dihedral on wing for fun performance

Although it’s not covered off in all manuals, a very handy thing for the ARF plane owner to do is to ensure your servo push rods maintain firmly connected to your control surface horns (for obvious reason!).

The simplest way to achieve this is to cut off a small 3mm length of silicon fuel tubing that our nitro friends use (here’s an example), and stretch this over the clevis. This way you’ll prevent the clevis disconnecting, and you may have a much longer-lasting (and far safer) radio controlled model airplane as a result!

Below you’ll see a photo of the aileron linkage found on the underside of my 48″ electric Decathlon’s main wing and the fuel tubing wrapped around the clevis.

Till next time – happy landings!

Alex

Note the silicon fuel line around the clevis.

For us electric RC fans, the C rating is simply the measure of maximum safe dischange a battery can take over a sustained period of time.

As you’re probably aware, RC planes and helicopters draw significant amounts of current when we’re using them so this is an important concept to be aware of.

In simple terms, “C” acts as a multiplier of the mAh capacity of the battery. Here’s a quick table I’ve put together:

Discharge Rate    Time to Discharge   
     1C                1 hour
     2C                30 mins
     4C                15 mins     
     8C                7.5 mins
     20C               3mins
     etc...

As you can see, the higher the discharge rate (or current, or throttle position), the quicker it takes to discharge a battery… common sense really

A Park Flyer example

When on WOT (wide open throttle) our DHC Beaver rc plane draws approx 18A*. Depending on the battery capacity and “C” rating will depend on whether we are causing damage to the battery discharging at these Amps.

Radio Controlled Beaver

In this case, I use a 1500mAh LiPo battery, rated to 20C (just like this one).

So let’s work out if we’re causing too much stress on the battery:

• We know that this airplane draws 18A on full throttle (with the 3 bladed 8×6 prop I’ve fitted)
• We know my battery has a 1500mAh capacity (or 1.5Ah)
• Dividing 18A by 1.5A gives us 12…  this is the discharge rate “C”

Maximum current draw at WOT    /     mAh battery capacity    =   actual discharge rate in “C”

As the battery is rated to 20C, if I’m only discharging at 60% of it’s maximum (12C) when at full throttle, we can be sure I won’t be causing damage to my battery. And that’s assuming I fly around the flying field  at full throttle the whole time (which I don’t given it’s such a light model).

At a glance – determining the maximum discharge rate of a battery

“C” rating    x     mAh capacity    =    max Amp draw

A simple way to determine the maximum Amp draw a battery can take is to multiply its capacity by its C rating. So using my 1500mAh LiPo as an example again, discharging at 20C would draw 30A of current. So that is the maximum safe amount of draw the battery can take, assuming the manufacturer isn’t overstating anything!

Again, 18A is only 60% of 30A so we’re not stressing the battery. In reality it comes down cool after most flights, generally not even warm, so all is good here!

What’s the Burst figure?

You may see that some LiPo’s actually have two C ratings – the “burst” and the “constant”. Often the burst figure is not labelled on the battery, but is rather in the sales literature (example).

The manufacturer is essentially stating that for periods of no longer than 30 seconds, the battery can discharge at the “burst” C rating. Personally I don’t like to discharge any more than approx 60% of the stated “constant” figure, as doing high rates of discharge repeatedly tends to shorten the life of your battery.

Furthermore, by buying getting a higher voltage battery, you can drop the Amps required to achieve the same wattage, which is generally a more cost-effective solution (a lesson for another day perhaps – for now just remember from your high school lessons that Amps x Voltage = Watts).

So – even though you may see burst figures, my preference is to ignore them, and do all your calculations based on the “constant” maximum discharge rate – you’ll be financially better off in the long run.

And finally, what’s the difference between LiFePO4 and LiPo Batteries?

Without going into the chemistry, LiFePO4 batteries, also known as A123, allow much higher discharge rates than lithium-polymer batteries. RC heli pilots who require serious amounts of discharge (40C and higher) are starting to look at these, and as the price comes down it is likely these will become more mainstream.

I hope this all makes sense – and please feel free to comment on this post, or drop in some examples of your own for us to work with!

* we measured this with this watt meter, connected it between the battery and ESC .

Zippy Flightmax LiPo Battery

It is very easy to change connectors, but before you do that, you need to decide which one to standardise on – and this is the tricky part.

I’ve recently been forced to make this decision, as one of my favourite sources for LiPo batteries (HobbyKing), recently changed all their battery connectors to their own proprietary standard.

Up until this point, I have been happy running Deans connectors, but now had the choice of either paying $5 per connector (about 10 times more than I was previously), or to find an alternative. So my choices are thus:

• stay with the Deans connectors and find another source to buy them from, as HobbyKing are not stocking them anymore.
• change all my ESC and battery connectors over to the HobbyKing format (XT60).
• change all my ESC and battery connectors over to Horizon Hobbies’ format (EC3).
• find another connector.

I hadn’t been entirely comfortable with the Deans’ connectors (they spark a lot, and I found them a bit too hard to disconnect quickly), so these were discluded. Even though I like HobbyKing gear, I don’t like the idea of moving to a completely new format which is not widely used – although I admit they do look great.

So I decided on EC3 connectors for the following reasons:

• they are very easy to connect and disconnect, and very few sparks are present.
• they are easy to solder and attach to ESC’s etc.
• they are used in ParkZone aircraft – so if  I do buy their new P-51 foamie I won’t need to resolder any connectors.
• I can buy a packet of 10 from HobbyKing for around $6.00.

So that settles it then, not particularly scientific but EC3 it is! I bought 3 bags to ensure I don’t run out any time soon.

We use LiPo (Lithium Polymer) batteries for two main reasons – they’re light, and they’re powerful. More often than not we’ll be discharging our batteries at 15Amps or more, and with the more powerful aircraft (such as the Pitts), this figure will be closer to 30A.

Although they are stable, these Lipo batteries do pack quite a punch, and as such, care needs to be taken when storing them.

Check out this video to see what happens when you treat your LiPo’s badly:

[youtube=http://www.youtube.com/watch?v=SQ0SNESIkWk]

So here are a couple of precautions to ensure your don’t burn down your house, or your car when you’re charging or storing your packs:

a) charge them in a fireproof bag, such as one of these

b) don’t charge them too quickly (never more than 1C – the mAh rating of the battery).

c) store them uncharged in the same fireproof bag (at between 3.7V and 3.8V per cell)

This way you’ll keep your property safe, and your batteries lasting for plenty of time to fly your planes!

Until next time, blue skies!

Alex

LiPo storage gone bad (image from RC Universe)

Park Flyers are wonderful examples of model flight – nice and small, fully functioning radio controlled aircraft – and a great way to learn, meet people, and have a whole lot of fun, regardless of what stage of life you may be in.

Over the coming months we’ll discuss everything from building tips, aerobatic manouvers, may touch on some of the safety aspects of the hobby, as well as the electronics behind it and “how it all works”.

So please check in once or twice a month, and feel free to comment on what we have to say.

Until next time – enjoy your flying!

Alex (on behalf of the team at parkhobbies.com)