http://www.hux.net.au

I took the boat out again last weekend and we did some more tinkering to get more speed.  The trim tabs did not improve performance, they hindered if anything so I pulled them off the boat.

It was flowing nicely, the copper pipe helped with the heat in the coupler but i’m going to change it for something a little smaller to get more surface area contacting the header pipe.

The level in the pond is getting really low now, too many shallow spots etc.  It’s probably time to either find another spot or possibly shelve it for now.  Might still see maybe one more installment but i think i’ll end up waiting for some more rain to fill the pond rather than going back to the salty river.  Time will tell.

So we took the boat back down the pond for another shot.  It went superb!  I would have to say that it was the fastest it has run yet.  With no real problems causing us to take it home it gave us the opportunity to give it a bit of a tune and get some more speed out of it.  The latest video shows it going significantly faster and now on 98 octane fuel and a different plug there is no missfire.  It was truly singing!

The water level was getting a bit low in the pond now uncovering 2 ‘islands’ in the middle.  It proved to be a little hard to negotiate between them so i stayed in the bigger area.  It looks like i’m just doing circles but infact the back run is quite straight.

The boat flipped a couple of times, the last one got caught on video but the first one was much more spectacular.  The boat held up well tho and once the water was out of the engine it started fine.

So, on to the coupler.  Well, i would say that it’s still the best solution so far but it’s still not quite up to the task.  After a full tank of juice (first time!) it was a bit melted. The problem is that most gas powered boats have water cooling the exhaust header so any product that i get is likely to only take 200 deg or so.  Mine does not have any cooling at the moment.  So, what i have decided to do is wrap some 1/4″ copper pipe around the header about 4 times.  I am going to run cooling water through it from the rudder and see what that does.  Hopefully this will help reduce the temp of the pipe and therefore preserve the coupling.

I have also got some stainless sheet to put on the back of the boat as trim tabs to help get it out the water a bit better.

I’m working on trying to get an onboard cam going too

With the leg now complete, i moved back to the exhaust.  This has been a problematic area from day 1.  The problem is associated with the poor balance and vibration in the motor.  Basically, the exhaust is shaking itself to death…

Originally it was solid all the way through but the thinner stainless of the pipe fatigued and cracked from vibration.  So, in the last run i tried a silicone coupling i got from rcboatbitz but it only lasted the previous run before splitting and that’s what caused the boat to stall at the end.  It was not really good for the job as it is designed for much smaller pipe and it was stretched to go over the 1″ pipe of my setup.

I’ve now just fitted a product that is made by octura.  This one is still silicone but it’s reinforced with 4 layers of fibre as well.  This one was 7/8″ so it’s still a slight strech over the pipe but not as bad as the other one.  I have since found that octura do the same part in 1″ as well so if this one splits i’ll order one of them.

The bigest problem is the heat - it’s classed as a ‘high temp’ coupler but i have no idea on the actual rating of it.  I tried to find some specs via the oracle that we know as google but it turned up nothing so far. With any luck it will actually hold up…

So after the last run I saw the need to redesign the bush/bearing setup in the leg.  the original design simply used 2 collars of teflon around the shaft.  After visiting a few sites and seeing how some other ‘DIY’ designs were done i settled on one developed by the guys over at Oxford County based on some K&S brass tubing.

The outside is 5/16″ and the inner is 9/32″.  The 1/4″  shaft perfectly slides inside the 9/32 and that slides perfectly inside the 5/16 tube.  The smaller of the 2 tubes is cross drilled to allow for lubrication between the shaft and larger tube.

The bearing holder is a little bigger as well as now going for a stainless ferrule.  No real advantage here but the only reason i went for brass on the original one is because the tradition is to solder the flex shaft in.  Instead, i ended up using Loctite shaft lock.  This is super strong stuff and never even hinted at breaking loose uner the torque of the ryobi.  So, to keep it looking nice this time, i used stainless.  Also, this time i have used a roll pin to atttach it to the shaft rather than grub screws (which were a little problematic last time).

Almost ready to rock…

I’ve been getting all my RC toys back in working order over the last couple of weeks.  One being my Traxxas T-Maxx monster truck and the other is the boat.  I sorta stripped the radio from the Maxx to put in the boat so i got another RX and a couple of servo’s to get the maxx running again.

The boat also needed a new radio box and some other minor repairs.  With a little work and some help from Tim, i got it back up and running.  I also found a new/better site to run the boat.  It’s the old (now abandoned) Lakeside Leisure park site.  There’s a nice little pond in the middle to run the boat on.  It has a couple of downsides like limited access to the bank and a shallow spot in the middle but the huge plus of it being FRESH water and not salty onkaparinga river water far outweighs them.  It’s not all festy and stagnant either like one might suspect.

I’m not 100% sure on the legalities of using the pond since it is infact private land but there are no signs up telling me to stay away and i did not even have to jump a fence or anything- just walk straight in.  Not only that, other locals seem to be using it extensively for riding motorbikes on. I don’t think i’m going to have too much to worry about.  That is, until the land gets sold off and subdivided as the land is for sale…

So, we got the boat in the water and even remebered the camera this time!  There’s a couple of problems with it after the run.  Mainly the fact that the rubber/silicone header -> pipe joiner split which caused it to stall (no back pressure).  I’m going to have to find something else to do the job. The engine also seems to either detonate or misfire every now and then - you can hear it in the video.  I think with 98 octane fuel and a bit more oil it should go away tho.  I’ve also made up a stand for it now.  Makes transport and use so much easier.

I’ve also now decided to make up a new skeg.  The current one is not ideal, it uses teflon as the bearing and wears too quickly.  I’m changing it to use brass and to have more bulk. More on that later.

In the mean time, enjoy the vid…

So now i’ve been bitten by the heli bug it seems that every time i look outside and there is no wind, by the time i get outside with the heli there is crappy gusty wind.

So, being a bit of a DIY person with some skills in fabricating, electronics and programming i decided to have a shot at making an Anemometer!

The process began by looking at some other DIY designs for the actual wind vane but that’s pretty much where the similarities ended.

Nothing was purchased for this project other than the PIC chip (AUD$10). - it was all stuff i had laying around home.

Mechanical:
I started with a PVC ‘T’ joint and worked from there.  I turned down a chunk of aluminium to plug one end and bored a hole through it to support a bearing.  The bearing i sourced from an old hard drive.  It was the bearing that the head mechanism pivoted on.

I then turned down the end of some delrin rod to use as a shaft for the unit. This slides through the bearing and is drilled and tapped on the end to support the vane assembly.

The vane assembly is made up of a disk of aluminium, carbon fibre rods and 1/2 ping-pong balls.

Mounted on the shaft is a delrin disk with the magnet from a PC case fan glued around it (more on this later)

Electrical:
The actual sensing of the revolutions is performed by a hall sensor salvaged from a PC case fan.  Being brushless motors, they rely on a hall sensor to take care of energizing the coils to spin the motor.  I pulled the hall sensor and the circular magnet from the fan.  The magnet was glued to a disk mounted on the main shaft.  The hall sensor was then mounted up near the magnet.

With the sensor taken care of, I needed to be able to time the duration of the pulses to give me some feedback.  Ths is where the pic chip comes in.  Now, i am fairly new to PIC’s but with datasheet in hand and using the Proton Development Suite Lite edition i was underway.  The code was the hardest part.  This is the first time i have used an LCD on a PIC and it took a while to get the code right but i got there in the end.

Basically, the PIC waits for a pin to go high and then low again and times the duration.  It then calculates the speed based on the diameter of the vane.  These vanes generally spin at about 1/3 of the actual wind speed, that is also accounted for. The hall sensor inverts signal every 90 deg so the duration of the high signal is only 1/4 of a rotation.  This means we can get 2 readings per rev.  If i really wanted to, i could make this 4 but it gives some time for writing to the LCD and calculations while the signal is low.

The hall sensor runs from 3-30v or something like that - a really wide range.  It’s a 4 pin device, Vcc, Vdd and 2 ’signal’ pins.  The signal pins simply toggle to ground depending on the magnet orientation.  I am only using one of the signal pins.  It is connected to a pin on the PIC which is pulled high via pullup resistor and then the hall sensor pulls it low.  Other than this, the LCD is basically directly connected to 6 pins of the pic as well as power, ground and LCD contrast.  I am currently powering the setup from USB so it has a stable 5v supply without a voltage regulator.  The final revision will likely have a VREG.

The prgram in the pic simply initialises the LCD and waits for the pin to go high, it then starts a timer and waits for the pin to go low.  It then stops the timer and does the calculations for speed and displays them on the LCD.  It contains a ‘timeout’ of 10s.  i.e if the signal does not invert for more than 10 seconds, it assumes wind speed is 0 and resets the timer.

the electrics are just on a proto board at the moment and there is still more work to be done, this is just the start.  I hope to have a programmable ‘diameter’ for the vane and also RS232 output of the speed so it can be logged to a PC.

Pics:

Ok, so i’ve been getting into the King2 and really enjoy flying it but what do you do when the weather outside is not all that great?

The answer is here!
I’ve purchased a couple more helis over the last couple of months.  The first being an Esky Llama 4 2.4Ghz.  This is seriously easy to fly and great for indoors.  Great for learning nose in and relaxing!  The only problem i have with it is that it is a little too subtle for my liking.  It does not like hard banking turns very much - The upper and lower blades tend to flex and touch each  other and will cause a crash.  Sure, there are extended shafts and things like that but rather than put my money in to a heap of mods for it i decided to try a different model…

Along comes the Walkera 4#3B 2.4Ghz Metal version
This thing is SERIOUSLY tiny!  At only about 20cm long (head to tail, excluding blades).  It runs off of a single cell 400mah lipo for about 7-10 minutes.  It is extremely nimble and FAST!  This little thing can be thrown around and performs really well.  I am very happy with it.  It’s not really for the beginner however, It takes quite a lot of skill to fly it.

Don’t let the apparent size of the pic fool you, here is a comparision of all 3 of my helis

Here is a clip of me flying the king 2 for the first time in about 9 months.  All blinged up now and flies much more stable.

Some time ago (back in september last year) I decided to try my skills as a helicopter pilot.  Having never flown any model, i knew it was going to be a bit of a challenge.

After looking at what sort of model i should buy, i settled on an E_Sky Honey bee king 2.  It’s a 6 channel CCPM helicopter.  It is capable of doing inverted flight and ‘3D’ monouvers so is a bit more advanced than the coaxial heli’s around the place.  I did not want something that i was going to outgrow in a hurry either.

There were a few reasons that i chose this model at the time but given the choice again i’m not sure that’s what i would have bought. It does have some distinct advantages however:

•   It’s CHEAP - ~$150 can get you a complete working King II and about $100 can get you a ‘barebones’ kit which is basically the whole thing minus the electrics.  
• Parts are plentiful and cheap in online stores like ebay.
• It’s more like a real heli with propper swash and variable pitch on the blades.

The downsides are that it’s not as fine tuned as one would hope. 

• The (brushed) motor that it comes with is useless.  It only lasts a few flights.  For me, that was about 10.  Luckily i had ordered a brushless motor and ESC when i bought it.  I really wonder why E_Sky even bother with the brushed motor as it is just not up to the task. 
• The tail authority is quite dismal.  It requires some mods to the tail box to get full slider movement and is still not overly responsive without changing the belt drive gear to a higher tooth one from a 3rd party company.
• The head develops slop quite quickly which makes it harder to fly.  Sure, you can replace parts but the design of the plastic head is not overly good to start with.  You do have the option for aluminium parts tho.
• When the battery is in the battery compartment the heli is not properly balanced.  You need to hang the battery out the front a lot to get it to balance right.
• The top frame is poorly designed and tends to be overly fragile.  There is a distinct weak point just behind the motor, this leads to flex in the frame which also affects gear mesh.  Not something you want
• The tail belt has a habit of coming off it’s guide rollers mid flight.  This compunds the tail problems and can cause the heli to rotate on it’s pilot.  New pilots get disorientated and will soon crash a heli that is not ‘tail in’ to them.
• The stock radio is ok but is not overly reliable.  I flew for some months with the stock radio but i found it to be ‘glitchy’.  Twice, it twitched causing the heli to rotate on me causing a crash.  Not expensive but annoying.

All of these problems can be overcome but not without spending some decent $$ to bring it up to scratch.  It makes the $150 pricetag sort of irrelevant since you would likely spend that again in upgrades and that is not including a new radio.

That said, i have found it to be a reasonable heli to learn with and i HAVE gone through most of these upgrades. It’s been shelved for a little while now since a blade exploded on me and ripped the heli to bits (darn wooden blades!),  then I got distracted with the boat but i’m hoping to have it in the air again soon.

Moving on from the King II i would be looking at a CopterX 450SE which is a copy of the more expensive Align T-rex 450SE.  It can be had for about $150-$200 off ebay, just add your own electrics.  It’s a much more stable and bigger heli.

Ok so over the last couple of weeks i’ve been tinkering with the boat trying to get some more speed out of it.  With the 280 prop and some luck we got a really good run out of it with some decent speeds.  Unfortunately on that run the exhaust cracked from vibration for the second time.  I decided that i’d take the oppotunity to now make a new pipe that was tuned for this engine’s port timings as well as reduce the power band for the pipe by about 1500 revs (bringing it to about 8500 rpm).  I also decided on a flexible silicone coupling.  The new pipe is all stainless too.

The first vid is slightly older and it was getting along better than in the second one…

 The radio box keeps getting water in it so i’ve got to make a new one of them too.  Hopefully soon i’ll be giving it a shot with the new pipe and some more tinkering it should get moving nicely..