Wednesday, November 30, 2011

Last Mod and New Mod

The 3 blade prop was just for testing
So, as promised, I have pictures and updates on my last power train modification/update.  As I mentioned in my last post, I tried to match the motor selected for someone else's motor mod and they used a "V3" brushless outrunner.  What I came up with (that was also available at the time) was the Turnigy D2826/10 1400KV brushless outrunner.  I am not sure what the 2826 represents but I believe that the /10 refers to either the number of poles or magnets.  The 1400KV definitely revers to the number of no load RPM per volt applied.  This helps you figure out what kind of RPMs you can expect with a given battery pack.  Since the Wild Hawk runs a relatively small diameter propeller, I wanted more RPMs.  I would have preferred something in the 1800KV range, but this is what was available with the other physical features I wanted.  As I said, I selected it not only because of the electrical characteristics, but also because of the output shaft and prop shaft adapter and the bracket and mounting method.  I really like the self centering prop shaft adapter and how it attaches securely (like a drill chuck) but also would allow for slippage if the propeller were to impact the ground or some other object.  I also like the motor mount and bracket because it is very easy to work with.  I did make sure that I used Locktite to secure the screws that hold the aluminum bracket to the motor since it would not be easily accessible.

 Now on to the speed controller.  I was looking for a controller that would handle 15 to 18Amps, but again, the one I really wanted was not available (back ordered), so I found this one for more money, but  from the description and people's reports this one can easily handle long bursts to 40Amps.  It is programmable with an inexpensive programming card but can also have basic programming done with your transmitter throttle settings.  It is a little bigger than I expected, but oh well, I have it and it works very well and I don't think I will have to worry overloading it.

Finally the battery.  I was going to just use the batteries that I made from laptop batteries, but decided that they were just too inexpensive to pass up.  I found this (again) Turnigy 2200mah 3C 11.1V pack.  It was listed with a discharge range (20 to 30C), which seems a little unusual, but it was easily above what I expected I would use.  20C times 2200mah means that it could supply at least a maximum discharge rate of 44 amps.  See, plenty of performance for this setup.

The nice thing about having everything Turnigy is that all the connectors fit without any trouble or issue.

Now the new mod is a mod to keep my "high tech" camera mount from damaging the wing again.

In these two pictures you can see the damage that occurred to the trailing edge and how the tape cut into the wing under the force of the weight of the cell phone.  Of course, this would not have happened had I been able to learn how to land properly.  But, I have not, and I'm not sure when I will.

OK, before I get to much further into this, I guess I should tell you about some background on my method of this repair/mod.  So, some months ago, when I first got going into repairing my Wild Hawk and using tooth picks, foam chunks, and hot glue, I introduced my Dad to this.  He started to kind of take off with the idea of using cheep and free items to use for repairs.  My Dad told me about how he was collecting free coffee stir sticks to add to his supplies.  Now, I'm from a 100% Dutch family and predominately Dutch community and I am no stranger to the tendencies of the Dutch to be, shall we say, penny pinchers.  But my Dad collecting wooden coffee stir sticks struck even me as going a bit far and was something that I was not going to do, especially since I could get all I wanted from my work for free.  Well, now I'm looking at the issues with my wing repair and reinforcement and what comes to my mind as being the perfect item to assist with my repair?  You guessed it, a wooden coffee stir stick!  Did I have any in my supplies to assist with this repair?  No, of course not!  I'm sure my Dad had many available and could have fixed this issue on many wings, but not me.  I was not cheep forward looking enough to have stocked up an effective supply.

Well, after scowering my wife's endless craft supplies I had to settle for a tongue depressor.  If I couldn't find a wooden coffee stir stick, a wooden Popsicle stick would have been a good second choice.  Well, we did not have any of those either.  So, a wooden tongue depressor was what I was going to have to work with.

OK, on with the repair. I molded the foam back into place and started looking at how the wooden tongue depressor would be used to re-enforce the location.  I used my Exacto saw and started cutting the depressor down to size.

Soon I had a piece that I was happy enough with and was ready to hot glue it into place.
Now I strapped the phone into place to check things out.  You can see how the phone looks on the bottom side of the wing with the strapping tape holding it in place.  The photo to the right and below shows the top side of the wing with the trailing edge re-enforcement and how the strapping tape wraps around and is prevented from doing more damage.

Now I'm waiting for my free time to align with good weather to try this out and see if it really works as expected.

Thanks for stopping by my blog and please post comments, good or bad.  Be sure to come back and check for future posts.

Power Play and Photo Phun

If you saw my last post you know that I completely revamped the Wild Hawk's power system; new motor, new speed controller, and new LiPO battery.  It was hard waiting and I finally had a chance to get out and fly it.  I have to mention here that I also had a plan to take video from the plane using an old cell phone (still waiting for the shipment of the cheap mini DVRs to come in at Hobby King).  So, I went out to kill two birds with one stone.

The first item on my list was to just fly the plane and make sure all was well and to see what the performance was.  After making sure the speed controller emitted the appropriate beeps, I was set to go.  I powered up to full throttle and hand launched the plane into the air.  It flew very nice, but was not the rocket that I expected.  I had seen others mod their planes similarly and they seemed to go vertical until out of site.  Although I could tell I had more power, it would not "go vertical."  At first I was a little disappointed as i had done a lot of motor research to match a similar motor as, the Dutchman that I am, I was not going to pay the $40 for the motor recommended (I got mine for less than $20).

Any way, the newly powered Wild Hawk flew very nice.  I did notice that I could throttle way back and still not loose altitude.

So, that done, it was time to strap on the camera (and I do mean strap on).  I pulled out the cell phone camera and got it ready.  This was actually quite the ordeal as the phone is an early touch screen model LG and the touch part has been failing.  I found out from Google searching my issue that if I pealed off the top clear layer of the screen I could regain some of the functionality.  I did find out through trial and error that I also had to hold down the, now visible, connector area to regain functionality of the whole screen.  Also, going back a bit further in this part of the story, since this phone is no longer used and I do not have a valid SIM card for it, I had to set it up in, fittingly enough, "airplane mode".  This disabled the cell portion of the phone while still allowing for use of the rest of the phones functions.  I was not able to accomplish this until I resolved the touch screen issue.  OK, the last thing I did was to make sure that the phones video camera feature recorded to the internal micro SD card.  This last item would make it much easier to access the videos taken (I never had the special USB cord for the phone and I didn't want to deal with Bluetooth).

OK, now I was ready to strap on the cell phone camera and take some video.  The plane was still on from the last flight and ready to go.  I took out the roll of strapping tape (see, I really mean "strapped on") and cut off a long strip, about a foot.  I carefully placed this across the camera side of the phone leaving the rest evenly hung over either end.  Then I started the video camera and placed the phone on the underside of the wing and pulled the tape around the front and tail of the wing.  I made a last minute check of the controls, hit the throttle and launched it into the air.

It flew great!  The added weight of the phone (not insignificant) made not difference other than a slight trim of the ailerons.  I let it fly in circles slowly gaining altitude.  The day was a bit cloudy and pretty soon the Wild Hawk was fading in and out as it passed through some of them.  "Awsome" was my thought as I thought of what video I might be getting.  I continued to fly around and took the plane over some nearby homes and then back again.  As far as the power goes, I was able to cut back to 1/4 - 1/3 throttle and maintain altitude with ease.  This is certainly an improvement over the old power train especially with the added payload.  I flew for at least 5 minutes and struggled to bring it down to make a few practice landing passes.  This plane really wanted to stay up in the air.

A few seconds of air time video!

A bit of a rough landing and the plane was back on the ground without any real damage.  I did notice that the trailing edge of the wing with the tape had torn the edge a little, but not enough to worry about.  I was too eager to view the video to think too much about it anyway.  I unstrapped the cell phone and pushed the side button to reactivate the screen.  It was not still taking video!  I opened the list of videos and found the one it had taken.  For some reason it was only 43 seconds long!  Barely enough time to get the plane into the air let alone into the clouds.  Now I bummed.  I thought maybe I had made some sort of mistake in setting things up so I decided to try taking a sample video.  Sure enough, it stopped at 43 seconds again!  What's up with that?  I know that early cell cameras could only take short duration videos and thought this one might have a similar limitation based on resolution, memory, etc.

Well, I thought I would try one more time and see what I could get in 43 seconds.  I cut another piece of tape and got the phone ready to go, started the video recorder and strapped it on.  A quick check of the controls and tossed it into the air!  It flew great and for another 5 minutes or so.  No sense in cutting the flight short just to check the video and so I went back up into the clouds and enjoyed the flying.

I thought I would be able to make a better landing, especially since I had made two great practice passes.  This would not be the case as I made a typical knee jerk response a foot off of the ground and cart wheeled the plane.  There was no real damage to the plane as it was going slow and was so close to the ground, but the force did pull the strapping tape further into the trailing edge of the wing.  So, no more flying today.

I pulled of the cell phone and checked the video.  I knew that I was only going to get 43 seconds, but I had hoped to get more air time.  Well, even though I thought I had rushed and gotten into the air faster than the first time, I had actually done worse and did not get any air time at all.  So much for my first time out trying to get video.

The good news is that I really liked how the plane flew with the new power train.  Even though I can't go vertical, I still like the gain in power and I got significant flying time off of the new LiPO pack.  I do have a three blade prop that I might check the next time out.  We'll see if that makes any difference.

 I guess next time along with the fixes needed from this time, I'll include some actual details on the motor, speed controller, and LiPO pack I added.

Thanks for stopping by my blog and please post comments, good or bad.  Be sure to come back and check for future posts.

Sunday, November 27, 2011

Even More Power!

OK, I decided that I need more power.  I went online to my favorite hobby store site and purchased a new battery (2200mah, 3C), brush-less outrunner motor, and speed controller.  They actually came in some time ago but I just got around to installing and setting everything up.  A few things I had to take care of first like charging the battery and figuring out how to setup the speed controller.  I connected the battery to my charger and topped it off.  Then I checked the battery with my voltage checker and each cell read out very close, just the way I like to see it.  Now I needed to check out the speed controller as it usually requires a programmer to set it up.  I found out the speed controller could also be programmed to the default setting (which happen to be what I want) by using the transmitter.  This is done by powering up with the throttle in the full position and waiting for a certain number of beeps, returning the throttle to the off position and waiting for the required beeps, and then putting the throttle back to full and waiting for beeps again and then put the throttle back to the off position.  After all of this, it works just fine.  So, I setup the receiver, speed controller, battery, and  motor and checked everything out with the transmitter.  All worked as expected.

Now it was time to figure out how I was going to mount everything on the plane.  I started by removing the old motor and speed controller.  This required loosening the hot glue I had added to the motor, cutting the wires, and pulling on it until it came out.  Then I pulled out the wires from the speed controller, removed the power switch, disconnected from the receiver, and then completely removed it.  Now everything is out of the way and I can see how it will all fit.

I had already held the motor up in position next to the original and marked the nacelle.  I mounted a three blade prop that I had on hand just for reference.  So now was the time to start cutting.
I cut out a big chunk of the nacelle and made sure the surface was level.  I cut out a piece of hardwood to use for a firewall.
I marked the piece to find the center for mounting the motor.

 Next I tried the fit and found I needed a notch for the firewall to fit better.  I also figured it would give more stability since so much foam was cut out.

Now it was  time to dry fit all the motor pieces before permanently installing anything.  Everything was laid out to make sure I have everything I needed.  Since the screws to attach the motor to the aluminum mount would be hidden and not easily accessible, I made sure they were locktited in (reddish purple tube).  I decided to use wood screws with lock washers on the firewall since I would not be able to get to the back side if I used bolts with nuts once all was glued in place.

Here is the aluminum mount with the locktited screws, and to the right, mounted to the firewall with wood screws and lock washers.

Now that I was happy with everything, I decided to trim the wood down for a more aerodynamic profile.  I did this by holding the firewall in place and then tracing the nacelle outline on the back side.  Then I used a belt sander to trim it down to the profile I marked out.  Next I glued it in place with hot glue.  I made sure that the perimeter and slot were glued well.  I also added a vertical line to use to align the firewall with the seams in the foam (this helped a lot for centering).

I noticed that there was still a little flex in the new nacelle and so used some tooth picks to stiffen things up.  I ran two strait down on either side of the seam and then two more at an angle from just behind the wood to the front of the nacelle.

Now I screwed the motor back on being careful to make sure the wood screws went right back into the threads they cut during the dry fitting.  This I know will ensure the best performance and least chance of failure.  I also made sure that the screws were torqued down just enough to collapse the lock washers.

Now I need to get the battery in place.  I noticed that it was not going to fit at all unless I started cutting things up.  I really wanted it to be as far forward as reasonable to maintain the C. G.  I bit the bullet and opted for major surgery and sliced off the top of the nose.  This allowed for full access to the battery compartment.  I laid the battery where I wanted it and marked what needed to be cleared away.  I then used my soldering iron with a nail in place of the soldering tip and melted the foam until there was enough room.  I like to melt the foam instead of cutting it out as I feel that it helps to retain structural integrity.  Any way, once I was happy with the space, I hot glued the top back on.  I did not use any tooth picks for support as this section will be well taped with strapping tape.

Finally I'm getting to the speed controller.  It seemed to fit well just laying it out from the motor to the cockpit opening.  The two power wires were just far enough apart (being on either side of the controller circuit board) that the cover tab fits right in between them.  Instead of gluing it down, I opted for just taping it in place with strapping tape.  There were two reasons for mounting it the way I did.  One is that this was way easier than threading the wires through the foam, and two, it would provide for better cooling if needed.  So this configuration worked great other than the power connectors having to make an awkward loop to connect.  A little tucking of wires and rubber bands to hold down the canopy and no one is the wiser.

I powered up my radio then plugged the battery in (I no longer have an on/off switch) and everything worked as expected.  I am very happy with this and cannot wait to get out and fly this thing.

Thanks for stopping by my blog and please post comments, good or bad.  Be sure to come back and check for future posts.

Tuesday, November 8, 2011

Almost Lost

Well, this with this post I started with a new transmitter.  I needed something with more controls than the 3 channels that came with the Wild Hawk.  Especially since I added ailerons.  I was not satisfied with losing my rudder, as I found that I really needed it for making landings with cross winds like I seem to always have.

What did I do?  I headed off to my favorite hobby shop, Hobby King.  I looked through their transmitter options and realized that I did not want to spend a whole lot of money on a name brand system especially as I am still new to this hobby.  So I looked at their shop brand selection.  I found they had several transmitters ranging from sub $30 4 channel to just over $50 6 channel and all using 2.4GHz spread spectrum technology.  Interestingly enough there was only a few dollars difference between the 4 channel and 6 channel low end systems and I opted for the extra channels.

I received my 6 channel transmitter along with the USB cable to program it.  I love this transmitter and was looking forward to installing it and trying it out.

It took a little work to get the old receiver out and keep all of the connections strait but I did it and got the new and smaller receiver in.

It took a while but I finally made it to my Dad's place for some flying.  My first flight was in his back yard which is about 50 feet by 150 feet surrounded by fence but with orchards and clear views all around.  So after a few falls starts, I made it up into the air and really had fun flying around and getting used to the new radio.  I made one test pass and made good use of the rudder in lining up a test landing pass.  On my landing pass I did not account for the thermal conditions.  You see, my Dad's back yard is half grass and half pea gravel.  I started my pass coming in over the grass toward myself standing at the far end of the gravel.  Everything was fine until I crossed over onto the gravel and his the updraft.  This pitched the plane over and into some equipment off to the side as I lost control.

It took a bit of work but I got the plane fixed up again and ready for another flight.  By now the wind was picking up and I new I would have to the open field next door.  Out we go.  I get launched and am flying fine but I realize I am starting to fight the wind.  While I'm playing with the new radio and extra channels, I stray too close to Dad's orchard just behind me.  With my battery a bit low and the wind, I find that I can't bring it back and lose the plane behind me.  I just let the controls go neutral and shut off the power.
We finally found the plane lodged in the upper branches of a tree on the far side of the orchard.  It took my daughter climbing the tree and using a pruning pole to shake it loose.  Up in the tree the plane didn't look to bad.  Once down, wow, it was really messed up.  Both wing leading edges were gouged, the nose was gouged, one wing was bent up and the bamboo spar broken.  Lot's of work is going to be needed to fix it this time.
Next update hopefully all will have been repaired.

Thanks for stopping by my blog and please post comments, good or bad.  Be sure to come back and check for future posts.