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Gino CP's blog
Posted by Gino CP | May 08, 2009 @ 03:21 AM | 11,240 Views
Anyone who has built and tuned a heli knows he has one tool he can't do without. And for noobies, it is a must have. It's called a main blade pitch gauge.

We've seen these in an assortment of shapes and sizes. Often they are made from plastic. You clamp these on the blades, level out the flybar and eyeball the gauge's top edge with the flybar. Not an easy task for someone with "four" eyes. Then you manipulate the swing arm with one hand then hold the flybar level with the other. An easy task... if you are an octopus!

Thankfully grnbrg (an RCG member) thought of this paper pitch gauge. The grnbrg's Universal Paper Blade Pitch Gauge can be downloaded here.

I printed one out on office paper and cut it out with a box cutter. Once folded, clipped on with paper clips, and strung with a weighted (old ball bearing) string, I was good to go.

Prep work was easy. I checked my work table with a bubble level and found it to be level. I laid my 450 heli on the table and used a right triangle to verify that the main shaft was perpendicular to the table. I was all set.

Pitch readings was easy. Easier actually than a plastic gauge. I just kept the flybar level. I proceeded to program my transmitter to get zero pitch at midstick. I did some work with the swash mix , endpoints, and trim to get a balanced cyclic and correct collective range. Done.

Compared to my plastic gauge, I saw a few anomalies in my settings. The grnbrg's Universal Paper Blade Pitch Gauge offered better resolution because of the longer radius of the meter swing. You can actually see in between degrees.

Now my heli is better than ever. What started as a curiosity turned out to be a new member of my tool box.
Posted by Gino CP | Feb 20, 2009 @ 09:46 PM | 12,386 Views
My previous diy pack did not work very well. It was a mix of 2 sets of nimh with different capacities. Yes, I should have known better. I thought I could just use up the capacity of the weakest cells. Well, it wasn't so. Initially it received 1000mah charge. Lately I just consume 250mah until it requires charging.

I ditched that and assembled a pack from GP Recyco nimh AA batteries. These 1.2v 2150mah nimh cells are much like the new generation Sanyo Eneloop nimh batteries. They keep a charge even during long storage. Up to 90% charge in a 6 months and 80% charge in a year. For rc use, it will practically keep all its charge between flights.

This time I used 8 cells of identical capacities. Initial charge took in 500mah. I guess the cells were quite old since they were on sale. So it had about 75% charge left. They must have been sitting in the shelves for a year.

All topped up, I used it on my DX7. 4 4min flights, daily sim for 12 days and it still registered 10.2v. The pack doesn't drop its voltage in tx off condition. It only decreases with normal use. I am impressed. If I fly until the low batt alarm (about 9.8v) sounds off then this should last me a long time between charging.
Posted by Gino CP | Feb 09, 2009 @ 09:02 PM | 11,523 Views
It is no secret that I am on a budget run. I like good value for my money. I had splurged a hefty sum on my Revolectrix 3S 2200mah 25C lipos. I enjoyed their power. The lipos lived a good powerful life. Now, they have aged gracefully. They have set the standard.

A few weeks ago when I was toying the idea of owning a Dragonus, I was referred to www.chaosrc.com. The Dragonus boys were a wicked bunch and hard core 3D guys. On the site I saw a white lipo that sells for $25. The Dragonus 3D demo video was very compelling. Needless to say, I hit the Buy Now button

Initial Impression:

The lipo arrived in an oversized box with adequate stuffing. The lipo was black LOL. But very noticeable was how compact it was compared to the Revolectrix. It weighed 162g. That is significantly lighter. the Revolectrix weighed 180g.

A voltage check showed some imbalance across cells. A quick session on my balancer evened things out it less than 2 min. So on to the charger it went. I charged at a conservative 1.4amps. I wanted to try less than my usual of 1C just to see if it will prolong the total life of pack. The pack peaked at 4.16v across all cells. Not the 4.2v I was expecting but acceptable and well below the safe limits of proper charging.

Field Day:

First encounter with the pack was a big surprise. I was punching skyward each time I flip inverted. This was too much power. I have gotten used to something less and now I had to adjust to the power. I'm not complaining....Continue Reading
Posted by Gino CP | Jan 16, 2009 @ 06:56 AM | 12,080 Views
Ever since I got my CopterX Black Angel heli, Iíve been on a budget equipment run. I found some gems along the way. While the Fusonic digital servos werenít exactly budget items, they proved to be good value units. Perhaps the biggest find was the XMHobbies G401B gyro. Itís a $35 gyro unheard of until now. And we know how that went.

I was on a high with my new heli until my Revolectrix 3S 25C lipos decided to go on retirement. One by one, they lost their oomph. Excellent and consistent lipos. They had a great run.

So the hunt began for budget lipos. I donít know if you have noticed but there above our screens was a small banner for the $19 EZ Fly lipos from www.aero-nuts.com. This couldnít have come at better time. I am no stranger to www.aero-nuts.com. Iíve used their black 3S 1000mah 15C lipos for my Honeybee CP2. Excellent lipos. Up until I sold my CP2, the lipos were delivering good power.

To cut a long story short, I pushed the BUY button and now I have my brand new EZ Fly 3S 2150mah 25C lipos! The lipos were sent by 2nd class air mail and yet, they arrived from Hong Kong in a record 1.3 weeks. Packaging was robust and the lipo survived the journey.

INITIAL IMPRESSIONS

Part of my s.o.p. with new lipos was to inspect each cellís voltage. Any cell below 3v and it went back to the sender. The EZ Fly lipo registered 3.86v per cell across all 3 cells. This was a good omen. A quick session on my dedicated balancer revealed a perfectly balanced pack. Almost as...Continue Reading
Posted by Gino CP | Dec 31, 2008 @ 12:00 AM | 13,188 Views
DX7 SETUP FOR BELT TAIL HELI Updated Jan. 25, 2009
* Applicable to 120 degree (3 servo) cyclic helis

* Before setting up, bind your receiver to the transmitter. This is done by plugging the bind plug into the BATT socket in the receiver. Then plug the battery to the esc and/or bec. Then press the transmitter bind button at the back as you turn on the transmitter. Wait for the flashing receiver lights stabilize. When it has bound, the esc will arm. You can release the bind button. Turn off the transmitter and unplug the heliís battery. Remove the bind plug from the receiver.

* Keep the flybar level with the main gear (or perpendicular to the main shaft) when checking pitch values.

I. System Setup Mode

1. Enter the System Setup Menu by pressing Scroll Down and Select keys while turning on the transmitter.

2. Press UP or Down keys to navigate.

3. Go to [TYPE SELECT] and choose HELI for your model.

4. Go to [MODEL SELECT] and assign a model number for your heli. Use the Increase or Decrease keys to toggle between choices.

5. Go to [MODEL NAME] to assign a custom name. Use Increase or Decrease to select letter. Press Select key to move to next letter.

6. Then press the Down key to go to [SWASH TYPE] menu. Use Increase or Decrease key to toggle to 3 SERVOS 120ļ.

7. Next go to [INPUT SELECT] menu by toggling UP or Down keys. It should be
AUX2>AUX2 and GEAR>GEAR.

II. Function Mode

1. Enter the Function Mode...Continue Reading
Posted by Gino CP | Nov 18, 2008 @ 08:28 PM | 12,204 Views
I inadvertently used the wrong holes to mount my tail servo on my heli. Since the holes weren't aligned, the stress cracked to tabs. Just when I had given up the servo for dead, I remembered how we used servo tape to mount servos on rc cars. So I made a custom servo mount from an angled piece of Kydex plastic from my old rc bin. I then cut off the servo mounting tabs.I installed that on the mount using 3M automotive trim tape. The result is a sturdy mount that allows me to use 4 screws previously not possible.
Posted by Gino CP | Sep 03, 2008 @ 08:36 PM | 12,792 Views
I had a Cxarge M1 lipo only charger and I wanted to fool it into charging my DX7's 8-cell nimh transmitter pack. My charger had a temperature probe and a high temperature safety cutoff. Borrowing temperature charging techniques from my nicd days, I rigged it up to see if it will do the job.

I set the charger to charge a 3S lipo. The 8-cell nimh pack was well within the voltage range of a 3S lipo. I set temperature cutoff to 35 deg C. Our ambient temperature was 30-31 deg C. So that was a significant temperature rise. Of course when weather changes I may need to adjust that cutoff.

So I set the charger at 0.2 amps and taped the temperature probe to the pack. Charging went very well. Charging alarm went off at exactly 35 deg C. I had used a thermometer to validate this. Charging stopped.The pack had peaked nicely.
Posted by Gino CP | Aug 30, 2008 @ 09:59 PM | 12,839 Views
Grass cutting used to be my Holy Grail in this hobby. But after weeks of practice, it has become just plain hovering to me. The journey was certainly exciting. The first 40-foot flip took weeks of convincing to execute. Then one day, I said, heck, let's do this. 3 tries was all it took for me to get my daily dose of adrenaline. I barely used the pack and I went home with a 2 hour long grin.

For a few weeks, I tried sustaining the hover. I was unsuccessful. It just didn't click. I've mastered inverted flight in all orientations on the sim but it just wouldn't work for real. The breakthrough was a conscious command to "push the elevator" once I was inverted. That did the trick and I achieved my first sustained inverted hover.

The next few weeks was spent on controlling the hover. In a few weeks, I got comfortable hovering low. These last two weeks, I was cutting grass. It seemed I felt more comfortable with the heli this close. I could see what the heli was doing.

So what's next? Move on to tail in hovering. I've done inverted funnels on the sim. But I still get butterflies in my tummy everytime I turn that tail for real. Well, something to look forward to.
Posted by Gino CP | Jun 24, 2008 @ 10:22 PM | 13,767 Views
I flew the CopterX 450 with an AKE 480R38 motor with 11T. Power was good. Minimal bogging. At 3800kv, collective wasn't mind blowing but torque was impressive. Equally amazing was how efficient it was. Motor was cool. Thanks to its centrifugal fan. Lipo was just warm. Way cooler than with my 430L setup. ESC was hot. I was just pitch pumping and hovering in the yard so no cooling air or translational lift to reduce loads. 5 min brought down each cell voltage to a healthy 3.8v. This was far better than with my 430L setup which averaged 3.76v per cell. It used up 1285 mah. Average draw is just 15.42 amps.
Posted by Gino CP | Jun 13, 2008 @ 09:43 AM | 14,160 Views
After rebuilding my CopterX 450, I had massive tail vibrations. Anything that should be straight had been replaced. Main blades had been balanced. Still the vibrations on the tail fin persisted.

After much thought and hair pulling, I realized that vibrations can only be caused by an imbalance on a rotating part. Picking up on this thought, it was obvious that it was either the main rotor or the tail rotor was at fault. By rotor I mean everything that were attached to the main shaft or tail shaft. That includes the blades. So I figured, why not balance the rotor as a single unit? Ultimately it behaves as one anyway.

So I removed the main and auto gears to allow the main rotor to free spin. I removed any balancing tape on the blades. Then holding the heli on its side, the aligned main blades see sawed. I proceeded to apply tape on the lighter blade until the rotor leveled nicely.

Test hovering time! To my amazement, what was once a fin with a double image and audible vibration sound was now one image and vibration free. Phew! Full rotor balancing worked. Next up will be my tail rotor.