Zero Problem is Sorted

Went and visited Paul @nitrodude yesterday to see if he could figure out why my Zero was flying like such a pig. And yes, he had a solution and yes, it worked. Before I give you the soltuion let me give you the symptoms so that people searching might come across this if it suits their needs.

When I tried to turn left, the Zero would turn in okay, but then it would self correct (war birds aren't supposed to self correct!). When I tried to turn right it would hold the angle, but would start to nose in quite badly. When I pulled a loop she would roll to the right as she pulled the loop. However, she was moderately stable in flat level flight.

All in all, a most unsatisfactory aircraft to fly.

Here are some of the things I suspected which proved to have no bearing...

• Bent prop shaft. After a few heavy nose over landings the r2212 prop shaft seemed to be a fraction bent. I straigthened it as best I could, and cut down the prop shaft so the prop adaptor sat closer to the motor (thus reducing the size of deviation).
• Bad thrust angle. Didn't make any changes as I didn't know which way to change it.
• Tail Heavy. Added lots of nose weight (about 25g) and the model was certainly balanced just fine, but it made no difference. She was still awful in the air.

So, what was the problem. A sticker. About 1cm of red circle decal on the upper side of the left hand wing at the point nearest to the leading edge was not stuck down (flapping in the wind). I taped it down, based on Paul's advice, and she suddenly went back to being her normal self.

A sticker which was 80% stuck down was the cause of all my probs with the zero over the last 2 weeks. As was explained to me, it doesn't seem like much, but the sticker was effectively acting as an airbrake, and that close to the wing tip it is going to have a significant effect on your aircraft. So, get the stickly tape out now, and make sure the leading edge of the decals on your wings are taped down.

Testing Times

I can't bear it - make the bad puns stop.

5 Flights this morning all testing something or another.

First flight on the Zero was testing the tightening and adjusting of the engine mount. All good. The plane is back to her cheerful best.

Second flight on the Zero I was trying a new battery pack - a FlightPower 3s 1200mAh battery. Is a nice low profile, that I reckon would just about fit a stock GWS warbird (without needing to hollow out the battery compartment any. I needed to use a bit of paper wadding to secure the battery so it didn't slide about. Only about 20g heavier than my model engines 3s 800mAh, but most importantly, whereas the 800mAh has a C rating of 20 (16A - more like 14A continous in actual testing and flight) the Flightpower can do 24A continous and with the ewatts motor and 7x5 provides 15.5 A steady according to the clamp metre. The battery is on loan to see if I like it from Super Toyworld in Fyshwick, who once they get to know you are often good about letting you "try" stuff out. I know I wrote about them in early posts but you probably haven't seen much about them lately. They are a good shop with true enthusiasts, they have no web site to speak of (so there is not much point mentioning it here), and their prices may seem a fraction high, but their after sales service is really really good - they want to make sure you are happy.

Anyway, back to the battery. It's amazing the difference an amp or two can make. Even though it only had another 1.5A or so the difference to the plane was actually quite interesting. Straight line speed - maybe a fraction more poke, but not enough to really notice when the plane is zooming in the blue. However, the power is enough to have increased the vertical time from 4 seconds up to 5 or 6, with maybe a possibility of going close to hovering her (I seemed to be quite close today). The extra flight time is a nice bonus, and the extra weight doesn't seem to do any harm to speak of. I reckon they have a sale there.

The other testing was trying different props on the elebee. The prop adaptor started playing up so I didn't get through all the props I wanted to test, but I tried a 5x5, 5.5x4.5 against the existing nitro 5x2.5. At the moment I still think the 5x2.5 has it. There is a 6x4 there as well which I didn't get to today.

I'm also planning to test all of these props on the Zero at some stage. I'm curious to see if the 5x5 might actually make the Zero go a fraction faster or whether there wont be enough thrust to overcome air resistance.

The Trouble with Zero

Don't worry, we aren't about to talk about division by zero, or even enter the debate about whether natural numbers should start at 0 or 1, or anything of the sort. We are talking about my Zero, a GWS Zero running an ewatts R2212 brushless outrunner.

After the loose mounting issue last week, I had the zero flying well the other day. However, this morning at Curtin (a splendid morning otherwise including a new flyer joining our morning PF "club") she was misbehaving again. I couldn't get her to fly straight and level, she half rolled whenever I used the elevator and just generally behaved like a little cow.

She had too much yaw in every corner she entered (not something she used to suffer from) and was self correcting out of corners, and rolling more steeply into others. Best I could tell this was not something I could trim out.

Anyway, I'll spend some time with her tonight to try and get her sorted.

Some new bits have arrived for my Microseether and lil squirt - batteries for both, speed controller for lil squirt and some connectors. Hopefully will cover the squirt tonight, and post some photos of her. Now just waiting for my cheap Hong Kong servos.

Oh, I have some new props for the elebee and Zero to see if I can eek a little more speed out of them.

The Tactical Approach

I wanted to try something new when it came to landing today based on something an ex RAAF member (not a pilot though) told. He told me that sometimes when the jets were coming in to land, and particularly if there were a few of them they might use what was called the "Tactical Approach".

Here's how he described it: Planes would fly, at 10,000 feet above and parrallel to the runway in the opposite direction to the landing direction. As they passed the end of the runway they would roll on their back, throttle back, engage the airbrakes and pull through a half inside loop easing out of the loop at the bottom to line up with the runway and land.

The advantage is supposedly the drastic reduction in approach distance.

It seemed like an interesting idea. Even though Curtin is big a couple of times I have been caught in situations where I either had a shortish approach over trees, or a land or hit the trees type scenario. In these situations the really tough thing is that last approach turn. If you have trees at the head of the approach and a short landing run you are between the devil and the deep blue sea. You can't fly too close to the trees for fear of becoming entangled, but if you fly too far away from them you lose some of your approach distance (which you might need). Also, you are trying to keep your altitude down so that you don't have a long approach, but against that is the fact that you need to pull a reasonably quick 90 degree turn - the sort that usually results in losing a bit of altitude.

More experienced pilots would probably be happy with making a more gentle turn with the wheels touching down very close to the completion of the turn and that is an option, but is one that takes finesse (I've managed something like that once myself) and practice.

So, I tried out the tactical approach twice with the zero today, and I have to say it shows a great deal of promise. At about 70metres distance flying directly downwind, and 30 metres altitude I flipped the zero on her back, closed the throttle and pulled through a half loop emerging at about 10 metres alitude. I held her level as she washed off some of the airspeed she picked up in the dive, and then gave her about 1/3 throttle (about the normal landing approach throttle level). She came in and landed about 10-15 metres behind me. Not bad.

Second run I had her in basically exactly the same position - maybe only 25 metres altitude as I was more confident about pulling through the loop, but this time let her wash of a little more altitude, very gently pulling her out of her dive (obviously you don't want your plane still plummeting at the ground at 10 metres - you need to almost be back to level flight by then) probably coming back to level flight around 6 metres. Once again landing speed throttle. This time I got her down about 20-30 metres in front of me, so I accomplished the landing approach from an altitude of about 25 metres in about 40 metres horizontally. Not bad methinks.

I didn't try the tactic with the RV4 because she didn't fly today. With the wind up I decided my two best wind beaters would get the nod (the RV4 is probably a good wind beater too - I'm just a little more careful as she is more fragile). However - I think she will do an even better job on the tactical approach. By engaging her flaps as she rolls over I should bleed of quite a bit more airspeed in the dive.

So - why does the tactical approach seem to work. A few things come to mind:

• Alignment. With the tactical approach you actually use the downwind leg to line the aircraft up. Once there, flip her on her back and pull through that wide loop (not too wide!!!). At this point you have effectively made your last turn. If you add the altitude to the horizontal distance you actually still have 100 metres or so of approach.
• There is no turn into the wind. If it is windy - the sort of wind that pushes aircraft into the ground when they turn into it then you really are between a rock and a hard place on that last turn. Too low, and you run the risk of being pushed into the ground by the wind, too high and you may not hit the mark. The wind may affect you in your half loop of course as well, but in a lot of ways correcting an aircraft perpendicular closeish to the ground is easier and more instinctive (pull up!) than having one on its side close to the ground (opposite aileron, pull up).
  
• Once you emerge from the bottom of your loop you have less things to worry about - the aircraft is essentially level - you may need to make some minor adjustments but probably nothing serious, and you need to remember to put the throttle back on to landing speed as your airspeed falls enough.

Having said all that the potential for disaster with this approach is definitely there, and I would certainly describe it as a tactic for pilots that know their aircraft well and find themselves in a spot of bother because of changing winds rather than something beginners should try.

Also gave the "Killer Bee" another hit out today - she is crazy. I think that high pitched whine was annoying the two guys trying to practice their golf but what the hey, I was only flying for 10 minutes or so - they can practice their silly game all day - besides which the distraction of that *noise* is good practice for shielding your mind 8-)

I got the impression the wind at altitude was a bit gusty by then. She was mainly rock solid, but she did get one or two slight nudges from the wind. Am a bit worried about the Feigao RX being flown out of range before I realise, but it seems pretty solid. Certainly more so than the one in the zero (which I switched the crystal in the other day in the hope of eliminating some of the glitch - not sure if it has worked yet).

I did a mixture of gliding, 1/2 and WOT with the elebee - she is still remarkably stable at slow speeds, and still has a really good glide angle (not surprising I spose as the weight of the new power setup is quite similar once removing the nose weight to allow for the heavier battery is taken into consideration). Oh - I didn't tactically approach the elebee either - I'm not sure how it would work with something with a really slick airfoil like that. It may just be too good at translating altitude into velocity. Maybe next time.

Also needing to mention that I found the cause of the Zero's bad behavior on the weekend - the base of the engine was not secured firmly against the firewall and so the slightest deviation in balance was making the engine shake around when running. Tightened up, and also gave the zero a little more downthrust. She is flying much the same way she did - perhaps a little bit better.

And the final note - in preparation for the indoor night on the 25th of Feb I bought a StevenAero "liddle squirt" from Nitro yesterday. I was told a 20 minute build - I was skeptical - I was right. I got the whole fuselage together last night - took about 2 hours of pretty easy modelling. Guessing the wing will take much the same tonight. She's not posted in the hangar yet but will be soon.

The Elebee Project Phase II

The Goal

If you've read earlier posts that you may know that the goal of the elebee project was to make my elebee fly faster than a Parkzone Stryker C (which is an awesome plane - my ambition is based out of respect, not out of any sense of dispargement).

The Power Plant

Although some have expressed doubts about the ability of the elebee airframe to handle this speed I wasn't terribly worried. I thought the main problem was getting enough power at a reasonable price. To that end I settled on an align brushless engine and speedie.

So, the final parts for the Elebee Project (or at least I hoped they were the last parts) were an Align 430L Brushless Motor 2800kv (I think they use them for their T-Rex helicopters) and 35A Align speed controller. Kit came from nitrodude. All up damage - $133. That seems pretty cheap given the result I got, but more on that later.

The 430L is an outrunner in a can design (meaning the outer shell doesn't rotate), making it easier to mount, with similar dimensions to a 400 speed brushed. It can handle 23A continous and up to 260 watts. Because I am running a 4s I cannot push 23A through, as that would be about 340 watts.

I bought a 35A speedie because I wanted to make sure that I had enough headroom to abuse stuff a bit if necessary to reach the speed I needed to.

The motor was secured in the tail of the elebee using cable ties - exactly the same mounting method as the stock brushed 400 speed motor. Although I was somewhat concerned about the motor slipping the ties, when you think about it the motor will drive a small prop, and although it will have significant thrust, it wont be have a lot of torque, and the thrust will not be that much more than say the weight of the aircraft twice.


The previous motor managed to actually slightly melt the "canopy" (a brushed 380 that really wasn't up to the job - rest in piece). So, I went for the simple choice and used just a little bit of balsa to prop the engine up (I don't like making things more complicated than I need to).

Given I was planning to run the motor pretty hard (at least at the 260 watts previously mentioned) I was keen to give the engine (and speedie) as much help in cooling as possible.

To this end I bought a motor heat sink. However, to make good contact with the engine I had to trim it so it fit between the cable ties (so it is only about 2/3 as long). Also, to fit in the space in the canopy I had to trim the bottom fin of each side of the heat sink.






With this done I turned my attention to the canopy. I extended the V in front of the motor mount (to allow greater airflow) and also cut holes in the motor mount section to allow the canopy to fit over the heatsink.





Once this was done the canopy fitted over the heatsinks on the engine. The heatsink of the speedie was also positioned in the v slot so that it could benefit from the airflow.

The prop was fitted using a 3.17mm prop adaptor and is an APC 5x2.5.

With the prop fitted I busted out the clamp meter to check how many amps she was drawing. Initially I didn't want to exceed the engine's ratings so figured the maximum amp draw was about 17.3A (~260w/14.8v). I tuned the JR TX on the up throttle throw so that at top position it drew about 17A. This translated to limiting the up throttle throw to 50%. Needless to say I had someone (Paul from nitrodude) holding the model for me whilst I was configuring the throttle throw. A few moments of me tuning convinced me that this was going to be a weapon, and that it was too loud to hang around for long.

Like all home built world speed record kit, the canopy is of course secured with tape...


The Test Flight

At Curtin this morning DJ watched with a mixture of bemusement and interest as I did the awkward running throw to get "Santa's Little Helper" airborne. I got a nice wing level launch, and opened the throttle. She quickly began building speed as dog walkers and golf putters looked up to see what that high pitched rackets was.

Once she had speed she was just phenomenal - trully unlimited vertical - a lack of rudder means she will normally fall of straight up, but it seemed like when I put her on her tail from level flight she put on 100metres altitude in no time at all.

DJ's bemusement was gone. Two giggling little boys (DJ and yours trully) watched as the elebee screamed, figuratively, and literally, around the field. Surprisingly, despite the speed she felt so solid in the air, responding perfectly and quickly to instructions. I pulled a wide 25 metre diametre loop - no problems.

I didn't want to use too much of the battery as there was more flying to do at Lyneham, so I brought her in after just a few minutes. Given the change has been weight neutral she still glides exceptionally well with a nice long slow speed glide curve.

Even after a couple of minutes of stuffing around, mostly at full throttle she had only used 400mAh or so, so I knew that I would get decent flight time out of the 2200mAh battery.

The Race

So we headed of the Lyneham for the usual "club" get together for non-club park flyers. Fortunately not only did we have a Stryker C there, but also a custom Stryker with 400w of power.

After generating some interest with the first elebee flight at Lyneham we put all the deltas up at once.

Of course, at altitude it is really hard to tell what speed is, but urging the other pilots for WOT we got all the Delta's running in the same direction at once.

Here is the result...

The elebee ("Santa's little helper") is faster than a Stryker C in stock trim.
It's velocity was indistinguisable from the custom stryker.

Wow - I didn't think it would be quite that easy, given the Elebee's heavier airframe. We seem to have hit a sweet combo with the 5x2.5 prop although we will try some others later.

So..., would you like to see the video. There are three options - a .mov version (quicktime - about 800k), a small avi version (should play on anything - about 8MB) and a larger avi version (13MB). The video isn't great, being taken from my digital camera, but it should give you some idea of the sound and speed of this plane. I'm stoked - this has worked out so well.

.mov (800K)
Small .avi (8MB)
.avi (13MB)

Final Note on Heat

The cooling and working within the engine's limits seems to work quite well. Even after a couple of full throttle runs the engine was cool enough to hold within about 60 seconds of landing.

Introspection

Those of you that spend too much time reading this blog (just as I spend way too much time writing it) will probably recall my post about the Bermuda Triangle which amongst a few nice pictures also discussed my somewhat troubling day at the field last Saturday.

I lost two planes (one of them not mine!) at the far end of the field. At the time I put at least part of it down to radio interference, and I still have some belief that that played a part, but there are other factors which are worth discussing because it is very important in life to try and learn from things that happen to you. In the end, it is not about who's fault it was. In the end it is about trying to make sure it doesn't happen again.

Many of you may not know that I ride a motorcycle and I try to apply the same principle there. I haven't yet had a close call (or an accident - only a couple of minor scrapes touch wood) which hasn't, on reflection, taught me something and or given me some new technique to avoid future incidents. I just want to talk about motorcycling to make a point of a mindset that you must avoid if you are trying to learn to fly RC.

Amongst the short termers (motorcyclists who are in the "sport" for 5 years or less) there is often a flaw in the rider's mental approach where after an incident they look for who or what to blame, rather than considering what actions they might have taken to prevent the situation arising. To want to blame someone or something when things go wrong is a natural human emotion - it protects our egos (which frankly we need, whether it is to ride a motorcycle, or to fly a $300-400 rc aircraft that might represent hours of our own effort), and it also has tie ins to our fight/flight response in situations of high stress (which is not so useful in the modern world unfortunately). However, it is easy to overcompensate, and once the emotional high of the anger dissipates, not spend the time to be honest with yourself.

This is a mental discipline that I think many people could benefit from. It is not about self flagellation. It is about accepting an imperfect world, and figuring out what you need to do to work with it.

So, with the sermon done 8-) here are my thoughts on some of the things that contributed to my RC accidents on Saturday:

• I was too low and too far away. If everything had run to plan it would have been fine, but this is the real world and things don't always run to plan.
• Recovery of an aircraft at a long distance is extraordinarily difficult. It is easy to lose perspective on a model at distance, particularly if that model is affected by inputs that aren't yours (wind shear, radio interference, etc).
• The decision to try and land the RV4 at distance, before trying to recover the engine, was a mistake. I should have done my engine stop drill - close throttle, open throttle, to see if power could be restored - there was plenty of juice in the battery so it was just a matter of busting through whatever caused the engine shutdown.
• Letting an unknown plane - the Extrafun, get that far away from me, on radio gear I'm not thrilled about (an Awesome RC 27Mhz TX - same model as the Electrafun) was a mistake. I was balancing that against the fact that the plane had a high stall speed, and I wanted plenty of room for the landing run up. Next time I'll keep in mind that range needs to get more weight in that consideration.

Til next time...

Gear Reviews

Introduction

The purpose of this page is to do reviews on various components that I have bought for RC Flying, and give you my thoughts on them. For each component I will try and tell you what application I am using it in, an overall rating, and why it is good, bad or neutral.

If you want to see what I think of planes instead of components take a look in the hangar.

Index

Batteries

• Elegance 3s 1500mAh 12C LiPo
  
• FlightPower EVO 20 3s 1200mAh LiPo
• Model Engines 3s 800mAh 20C LiPo

Electric Motors

• Align BL430L Brushless Outrunner in a Can (2800kv)
• Eflite 480 Brushless Outrunner (890kv)
  
• Ewatts 2212 Brushless Outrunner (1500kv)
• Towerpro 2408-21 Brushless Outrunner (& Towerpro MAG 8 ESC)

Receivers and Crystals

• MKS Receiver Crystal (single conversion)
  

Servos

• JP EnErG Micro 7.5g Servo (Cheap Servo)

Speed Controller

• Align 35A Speed Controller
  

Elegance 3s 1500mAh 12C LiPo

Date: April 2007
Supplier: North Queensland Radio Control
Application: I bought this battery originally for my Ultrafly P51, but now I use it for either my Tucano (ewatts R2212 brushless - 16A burst) or my GWS Tigermoth (400 brushed engine).
Price: 49.00
Notes: At about 120grams this battery is quite light given capacity, and bang for buck is a good deal. The only limiting factor is it is only rated for 12C continues, so 18 Amps. My application only draws 16A and although it is working if I fly the plane at WOT a lot, it is doesn't appear to be stressed. I've done about 10 cycles with mine so far and it seems to be holding up just fine.
If you don't need a higher C rating (and lots of applications don't ) then why pay for it both in terms of dollars and grams. Compared to my Model Engines 3s 1500mAh 20C the 12C Elegance is about 25 gram lighter and $20 cheaper.
Overall Impression: Provided you have an application that suits a lower C battery this is a great way to save money and reduce flying weight.

Back to top


FlightPower EVO20 3s 1200mAh

Supplier: Super Toyworld
Application: I use this battery in my GWS Zero teamed with an ewatts R2212 brushless motor. There are not many 3s LiPos that will fit a GWS warbird battery compartment, but this is one of them along with the model engines battery below (although my battery compartment was slightly cut before the fuse halves were glued together).
Price: 85.00
Notes: At about 104grams the battery is very light, given capacity, and unlike the model engines battery below is able to sustain the 16A that the Zero's ewatts r2212 draws at WOT from fresh to almost fully discharged. The battery is very thin and might even fit an unmodified GWS warbird battery compartment.
I get good flight endurance from this battery - 6-8 minutes at mostly WOT, or 12-15 minutes if I try to loiter.
Overall Impression: Although quite a bit more expensive than the model engines battery below this is a much better battery - it gives the sustained current, weights only a fraction more, and even seems to fully live up to it's capacity rating.

Back to top


Model Engines 3s 800mAh 20C LiPo

Supplier: Nitrodude
Application: I use this battery in my GWS Zero teamed with an ewatts R2212 brushless motor. There are not many 3s LiPos that will fit a GWS warbird battery compartment, but this is one of them (although my battery compartment was slightly cut before the fuse halves were glued together).
Price: 46.50
Notes: At about 80grams the battery is reasonably light, and gives good bang for buck as a value proposition although it is possible to get LiPos with more capacity for only a litte more weight but quite a few more dollars.
Battery's 20C rating is slightly exaggerated IMO - I haven't been able to draw more than 14.5A (should be 16A) from the battery when fresh which very quickly degrades to around 13.5A
Overall Impression: A good cheap upgrade for your GWS warbird even if you are still on Brushed power.

Back to top


Align BL430L Brushless "Outrunner in a can" 2800kv

Supplier: Nitrodude
Application: This motor is powering my "killer bee" elebee teamed with a model engines 4s 2200mAh LiPo, 35A Align Speed Controller and an APC 5.5 x 2.5 Propellor.
Price: $60
Notes: The outrunner in a can design means that this engine can just be mounted like a 400 class burshed electric which greatly simplifies that part of your project. If you follow the link to the killer bee above you will see I just mounted it using cable ties. You can also front mount it using screw holes. The motor is rated for 23A continous, but only 260watts, which I have taken to mean 23A on 3s continous. Currently I have the up part of my throttle on the elebee limited to 60% to stop too much juice going into the motor, but it seems to handle that little bit of abuse okay (clamp meter says it is doing about 300-320 watts at that position). These align motors are not repairable so if you bend a prop shaft you need to throw the motor away - one thing to be aware of.
Overall Impression: I'm certainly happy with the way this motor moves my elebee around the field, and the noise it makes is just to die for. This seems to be really good bang for buck for $60, but at this stage I don't know how much abuse it will take, which is apparently something the more expensive motors tend to handle.

Back to top

Eflite 480 Brushless Outrunner 890kv

Supplier: Nitrodude
Application: This motor is powering my Eflite Mini Pulse XT and is teamed with an Align 35A ESC, 3s 2200mAh Elegance LiPos and an APC 11x7 prop.
Price: $75
Notes: This is my first "expensive" electric motor and I am surprised at the difference it makes. For example - this motor can sustain 250watts comfortably which is about 50% more than the Ewatts below but seems to give more than 50% thrust. The MPXT is a monster on this motor with basically unlimited vertical which in an 800gram plane is quite an achievement. Mounting may be an issue depending on your application. For example - it doesn't fit the MPXT all that well, but with some dubro 4-40 1.25 inch bolts, and spacing with the included washers it just mounts. To get the best out of this low kv motor you really need to swing at least an 11 inch prop so be aware of that.
Overall Impression: A great motor that has buckets of power, thrust and very respectable pitch speed provided you can swing a big enough prop due to the low rpmv. The inclusion of a high quality hardware kit including a prop adaptor with the motor is a nice finishing touch.

Back to top



Ewatts R2212 Brushless Outrunner 1500kv

Supplier: Nitrodude
Application: I'm using this little outrunner in my GWS Zero and am planning to use one in my Phoenix Tucano.
Price: You can get just the motor for $15-20. The nitrodude pack includes an 18A speed controller for $55
Notes: This motor is cheap and fast. I'm running a 7x5 for the Zero, and she is probably doing an easy 70km/hr and has 4 seconds or so of vertical performance from WOT. The motor can do 16A for 60 secs, which is about what she pulls at WOT on the 7x5. One issue I have across is keeping the motor shaft running straight relative to the base - make sure you tighten the nuts that hold the shaft into the flight before your first flight.
Overall Impression: For $15 this is a great motor. Mounting options for GWS Warbirds are not great - I built a special firewall setup, but your bird will zoom around the sky leaving a smile on the dial.

Back to top


Towerpro 2408-21 Brushless Motor and Towerpro MAG 8 Speed Controller

Supplier: EP Planes (ebay store)
Application: This little cheap outrunner and speed controller are currently powering my Stevens Aero RV4 teamed with a Model Engines 3s 1500mAh 20C LiPo
Price: approximately $43 including postage.
Notes: This is a cheap and cheerful little motor that runs my plane beautifully. I get about 3 seconds vertical performance at WOT from level flight using an 8x4 GWS prop. Performance is better than a 400 geared brushed motor, maybe not quite as good as a 480 direct drive, but motor combo is quite a lot lighter and you are burning less amps. The MAG 8 has a few programmable options, and is straightforward.
Overall Impression: Provided you don't ask it to do too much this motor can help deliver solid performance to your sub 600g parkflyers.

Looking for programming instructions for the MAG8? Here are the ones that came with mine.

Back to top

MKS Receiver Crystal (Single Conversion)

Supplier: Taiwa (Wattsuprc)
Application: I've stopped using these crystals in anything I value. Maybe okay for indoor models at close range, plus fairly disposable models.
Price: $6.00.
Notes: Maybe all of my crystals came from the same faulty batch - three were bought together, the other seperately. I've taken a long time to reach this opinion cause I don't like to discount stuff when it might just be how I am using it but I get glitches - way too many, which dissapear as soon as I switch to other single conversion crystals. Don't read this as a reflection on Taiwa - they are a top shop with top customer service.
Overall Impression: Don't use these receivers crystals in any model if you can avoid it.

Back to top

JP EnErG Micro 7.5g Servo (Cheap Servo)

Supplier: Super Toyworld Fyshwick
Application: I'm using two of these cheap servos in my GWS Zero (rudder and elevator) and two in my Phoenix Tucano (wing servos)
Price: $9.95.
Notes: With over a 100 flights under their belts the servos in the GWS Zero are not showing any problems whatsoever. It was these little servos that convinced me that you don't need to spend $22/pop on Hitech servos, particulalry in cheap foam based parkflyers. Best I can tell, the odds of the airframe outlasting the servos doesn't seem that high and on that basis I'm only using high quality servos in aircraft I *really* value like the RV4.
Overall Impression: In the air these servos seem to be indistinguishable from Hitech HS55s. Maybe they wont have as a long a service life, and they will be thrown out rather than recycled at the end of it, but I fly a lot and these servos dont' seem to mind the work at all. Buying $10 servos rather than $20+ saves reduces your avionics bill for fitting out a new aircraft by about 30% which is nothing to be sneezed at.

Back to top

Align 35A Brushless Speed Controller

Supplier: Nitrodude (and also Taiwa/wattsuprc)
Application: I'm using one in my killerbee flying wing and one in the Eflite Mini Pulse XT. For the killerbee is teamed with a Align 430L Brushless, for MPXT is teamed with Eflite 480. Maximum power for either setup is around 280watts, and maximum current is around 24 Amps. Killerbee has 4s battery, MPXT has 3s.
Price: $73.
Notes: This ESC is really built for helicopters (the T Rex) range, but seems to do a pretty good job in my planes. This 35A ESC is the price of a lot of other 25A ESC, and although I haven't tested it in the 35A range it certainly seems to handle the roles I have it in just fine. Lots of programmable options - includes instructions. However I've just used mine straight from the pack and haven't had any issues.
Overall Impression: Good bang for buck. Seems like a pretty reliable ESC.

Back to top

Rumours of her death...

Have been greatly exaggerated. Some of the greener flyers not familiar with balsa were a bit worried the RV4 was kaput. Not so.

She has gone back together quite quickly. About 2 hours was required to get her all glued back together. One side of her needs to be recovered (I removed the covering to get everything glue back together on that side).

If you build a balsa kit plane make sure you don't throw out the scrap balsa at the end!

Unfortunately I wont be flying her tomorrow. Although she is basically ready to go I need a new wing bolt for her - the head of one of the ones supplied snapped of in the crash. I haven't re-covered the right hand side yet either. Shouldn't take long though.

Hopefully I might have her flying again by Monday.

The Bermuda Triangle

When a post about remote control flying starts with a title like "The Bermuda Triangle" you just know that tales of woe are sure to follow.

The day started well at 7:30am at Curtin.

We (a friend and I) took the opportunity to get a few photos of our aircraft in flight.




The Zero, with her new brushless engine tearing up the sky.








DJ's Tiger Moth buzzing about.











And the RV4 stretching her wings.











DJ gave his Electrafun XP a buzz as well, but you all know what they look like in flight so I shant bother with photos of that.

It looked like a great day for flying. By 9am the wind was still low and we headed out to Lyneham in anticipation of some more great flying. You can see where all of this is going right - it's all running too well.

Out at Lyneham I was trying to assist Canberra-Crasher (his handle from rcuniverse.com) getting his Extrafun (not Electrafun) going. After testing the battery and amp draw we figured out why his Extrafun wasn't making any thrust - the prop was on back to front (a mistake I have made myself when I went to maiden my Tiger Moth all that time ago).

With that sorted we got him to try and taxi out the Extrafun - it needs a lot of airspeed and in the end he ran out of space and touched a wing tip trying to turn out. We got the plane back - no damage, and I agreed a little reluctantly to take it off and get it trimmed out for him.

The extrafun is no beginner's plane. With the throws set way down it might be a reasonable second aileron plane, but unfortunately this one had full throws, and you didn't want to really move the control sticks more than 1/4 the travel they had on the TX. After giving some observers a slight scare I finally got the plane turned in a safe direction and trimmed out.

I dared not bring down the airspeed because of how violently she seemed to stall, although once I had her trimmed I rolled back around 2/3 throttle. Getting her trimmed, I asked CC if he wanted to take over, and with the plane headed in one direction handed across the TX.

He took it and flew some wide circuits around the field. He was being very delicate on the controls, and seemed to have command of her okay. However, we agreed somehow that I was going to land her.

So, I took the TX back and sent her down towards the far end of the field to get the approach right (wind from behind). I'll be honest - I was worried because I thought with the stall speed of this thing I was going to have to land her quite hot.

I started to turn her back towards me - she snap rolled onto her back (or that is what it seemed like). She was only at about 10 metres. I quickly rolled her back over. She rolled straight over onto her back again and started to nose in. This time it couldn't have been a snap roll - the physics weren't right. I fought to roll her over and get her back, but it was too late, and she nosed in. So there I was... holding the TX for someone else's plane which had just crashed into the ground. On the plus side CC was very good about it. The plane wasn't badly damaged (kind of tough) although there was a punctured LiPo which ended up in a Hungry Jacks cup with water, and it looks like the 480 motor was seized up.

So, what caused that crash - interference perhaps? I really don't think it was pilot error. Anyway, the day was not done and worse was to come.

The RV4 went up for a flight - the first time I've flown it at this field with so many people, but the airspace wasn't too busy. She was flying just fine, no problems whatsoever. However, down the other end of the field I seemed to lose power half way through a banked turn (yes very close to where the other plane crashed). Fearing the LiPo was discharged (although it would have been very early) I turned her back towards me to try and get her back for a landing. She twitched about in the air also (with a PCM RX!). I did my best to control her, and bring her down easy, but she ended up touching a wing tip as she came down at a distance where I could not easily discern her attitude.

Believe it or not, the damage is not as bad as it seems. Less serious than what I have repaired on this plane previously. All the same, it was a blow to confidence.

Shortly there after two of the more experienced pilots both crashed planes in the same area. One was a stryker C - no damage. The other was a big scale decathlon - which fortunately was upright when she lost power, and just snapped of her undercarriage when she came down hard.

Four planes seemingly brought down by interference. Like all crashes you do wonder whether there was pilot error, but particularly when it came to the RV4 I know that I did nothing wrong, the plane was well balanced, and testing on the ground revealed the LiPo still had heaps of go. A JR Proprietary SPCM receiver is on that plane - those things are almost bullet proof when it comes to interference.

Am left wondering whether Lyneham is a good place to be or not for flying. Anyway, the RV4 will be repaired, and I'll be flying again tomorrow (although maybe not the RV4).

Oh, a final note - DJ almost busted another wing on his Electrafun XP. I don't think this has anything to do with the Bermuda Triangle - just his obsession with high G manuveurs. He managed to bring it in for quite a decent landing regardless.

GWS Tiger Moth 400 Undercarriage Mod

Been a bit slow on the blog this week. Only a couple of mornings flying, and nothing in particular to report. But there is something I wanted to share. A mate has himself a GWS Tiger Moth 400. I warned him about the snap happy landing carriage. He landed - the undercarriage snapped off, and he decided to "fix it".

Next time I saw his TM he had done this interesting mod on the undercarriage which has made it very strong. The one time I have seen it land with this arrangement there was no landing gear folding - he nosed it over instead... 8-) But I mustn't be too cruel cause he has very kindly agreed to share it with us.

Letting him describe it in his own words:

The plastic bits I slotted into the wing were on the black snap-off sheet which came with the TM. They're the bits used for the landing gear on a GWS Warbird. With the bottom wing off, cut holes right through the wing so that the black plastic bits end about 1cm behind the reinforcing rod. You've gotta make sure you don't accidentally cut near either the servo hole, or the aileron guides.

Then epoxy the black plastic bits in, with the LG wire poke-through holes closest to the front of the wing. Let that set strong, because there's a fair bit of working to get the wire through supporting holes later.

2mm tie-wire (fencing stuff, from the hardware store) was used for the extra struts, and wrapped in 3mm heat-shrink tube. Basically, you cut a nice long bit and straighten it roughly. Cut a piece of heat-shrink the distance between the original LG wheels, and centre that on the wire. You then make two 270 degree twists, measuring out from the middle of the tie-wire, to as close as possible to the ~1cm vertical section at the bottom of the original LG. I used the end of a pair of needle nose pliers to guide that turn.

With the wheels off, you can thread the LG through the loops you've just made in the reinforcing piece. Then put the original LG in its place, with the straight edge of the tie-wire supporting the tail-end of the LG. Roughly bend and measure the wire to where it will go down into the new wing supports, and bend the wire there so it will go up into the wing/fuse. You want this bend to actually put a tiny bit of forwards pressure on the original LG, so it's pre-tensioned prior to landing. Cut the ends off to about the depth of the wing, thread some more appropriate length heat-shrink on each rearwards section, and you're nearly done.

With the LG off the plane again, shrink the heat-shrink tight around the wire. I at first did this on the plane, and both the engine cowl and yellow paint don't like heat. Then back on goes the LG, first in the original slot, then work the new struts into their respective rear holes.