vmsguy

I've finished the conversion:

My setup:

16 x 8 APC E-Prop
E-Flite 60 (400kV) motor
CC 80 ESC
ThunderPower Pro-Lite 4200mAh battery packs. 2 3S2P packs in series.

My bright idea, added slides to the inside of the fuel area, and the batteries sat on a plate, I could then slide the batteries fore and aft to adjust CoG. A pair of servo screws held the plate in place.

All up weight, 8 pounds, 14 ounces.

Maiden flight was Saturday (June 20). I videod it. (Will post when I get it processed.) Maiden could have gone better, the pilot was coming in for initial landing when another anounced his landing as well. My pilot took a bigger swing, and was starting to line up, when power was lost. The plane went in pretty soft, but still broke off the landing gear and broke the prop.

Structural damage is almost repaired. Haven't post-modermed the power failure. THe motor seemed pretty hot. but didn't see any "magic smoke" come out if it. Maybe the ESC lost it. Even thought the ESC is rated for 6 LiPos, I remember reading somewhere that it's not a good idea.. We'll see. First order of business once the plane is repaired is building a motor test stand.

vmsguy

I posted video to you-tube.

Here's the video...

http://www.youtube.com/watch?v=SH8qhJ_JHCY

It seems to have enough "Get up and go."

The "coming down and stopping" was a little rough.

vmsguy

Since my bipe went down, I've been working on it some more.

First, I had to repair the structural damage. I opted to change over to the fiberglass DuBro landing gear. It's a little wider (left-to-right) and marginally taller. I put in new plywood attachment point, a little deeper (front-to-back) than the original, to accomodate the gear. And put in some additional reinforcement. As a result of the new gear, the wheels are probably 1/4 to 3/8 inch further forward then they originally were.

Next I decided I put off building my motor test stand long enough. It turned out pretty well. It is essentially a drawer. The motor attaches to the sliding part, a digital scale attaches to the base. Clamp the base to something big and heavy, attach wires, and you're good to go.

I ran three (3) ten-minute motor tests with the bipe's setup. Each test was at about 2/3 power, with 10 second bursts to full throttle every minute. Encouraging, After each test, the batteries needed about 3200 mAh to recharge. An 8 minute flight should be more than possible. Also, after the tests, I took temperature readings. Nothing was over heated. The motor, the hottest, was at about 140 degrees, the ESC and Batts, 105.

The Watt meter says at full throttle I was drawing 1140 watts, and 52 amps, the scale says I was pulling about 8.4 pounds of thrust. At 2/3 throttle, about 400 watts, 20 amps, and 5 pounds of thrust.

I reworked the ESC location for better cooling, my two theories are 1) that the ESC overheated and shutdown, and 2) that I had a flakey battery that died mid-flight.

I added a few pictures of my work.
Picture 1: the motor test stand.
Picture 2: the new ESC mount.
Picture 3: the battery slides within the tank area.
Picture 4: the battery mount (notice servo screw in front corner to hold in place)
Picture 5: the battery hatch.

Glacier Girl

My Feedback: (4)

Quick questions. Your running a 9S set up right? You disconnected the bec in the esc, and are using a ubec or flight pack right?

Looking at the photos it looks like the red wire is still in the lead and not disconnected.

The CC80 is only rated for 6S with the bec connected, 12 without it.

If it's as I see it, you're running the built in bec and your problem is the bec can't handle the voltage and is overheating.

Just checked the Eflite 60's specs too. Max voltage for it is 28.8 or 7 lipo cells. And you're running 9 cells?

And your set up is pulling 52 amps? Max continuous for that motor is 40 and burst of 15 seconds to 60 amps. 52 amps is what your system pulls at all throttle positons, it's just how long it pulls that, that determines the speed. Meters get tricked trying to read anything but full throttle as they tend to average their readings over a set amount of time, the pulsing of the power to the motor tends to fool the meter into a lower amp reading at lower then full throttle.

Granted I'm know for stretching the limits of stuff, but it almost sounds like you are really pushing the motor and esc's bec capabilities way past where they should be.

I run the same motor and prop on my Hangar 9 Camel on 6S, and same set up spinning a 14x13 3 blade on my old Hangar 9 P40, and both flew great on 6 cells.

Glacier Girl

My Feedback: (4)

And you static tested the system for ten minutes at a time? I'm just amazed the whole set up didn't go up in smoke. I gotta be missing something here. Most folks agree a static run up should be to full throttle, and only long enough to take a meter reading. The lack of airflow on a static run(the motor and esc are sitting where airflow is at it's lowest on a prop) usually is a recipe for disaster when a system is run that long. I'm simply amazed the temps listed were real.

WOW, that's just boggles my mind.

vmsguy

Sorry, I had some typos in my previous post. I went back and edited them.

I'm running two (2) 3S packs in series. So 6S.

I have the BEC wire pulled from the connector. So that's disabled. I pull the red wire, but then place it outside the connector, then heatshrink the connector and the extension together. The extension was needed to reach the receiver. But by carefully removing the red wire, it allows me to change my mind later. Heat-shrinking the connection together keeps it all nice and neet, and prevents it from falling apart.

The pictures have wires disconnected for safety purposes.

I'm seeing 50-52amps, 1100-1140 Watts only during full throttle bursts. At 2/3 throttle I'm seeing about 20Amps and 400 watts.

jollyroger

My Feedback: (6)

You didn't say if you were using a separate BEC. If not the money spent will be well worth it. A CC Phoenix 80 with a 6S pack is at its limit as far as the BEC is concerned. I always use a separate BEC when using even a 5S pack. It does sound as though the motor is being pushed too hard. I would check out some of the Scorpions or Hyperions for more power and efficiency. with an 8 Lb.+ plane the power output looks a bit weak taking into consideration the motor efficiency which is not all that great in the E-Flight line.
I just ran your plane through my Ecalc with a Scorpion S-4020-14, 6S, and 14X7 APCE prop: This motor is rated to 80A/1500W.
50A
1131 watts created
886 prop watts
110 watts/Lb.
144 oz. thrust
At this current draw, the motor is not even breaking a sweat and still provides plenty of power at very good efficiency.
You can tell I'm somewhat biased towards these motors but I have been very impressed by the quality of workmanship and performance at the pricepoint htye are sold at.http://www.innov8tivedesigns.com/
Hmmmm, I may just have to build one of these myself.
cheers

vmsguy

I am not using a BEC. It is disabled.

I have a separate battery pack for the receiver.

I've got the plane ready to fly again (just have to re-check the balance) I'm going to have to take it to the airfield again, and see if I can talk someone into flying it. Hopefully get a few minutes a flight time, and a successful landing, so I can take more measurements.

I want to try a short flight, and get temps, and then figure out if things are good/bad/in-between.

beau0090_99

Hey Lyndon,
Good luck with the re-maiden. Your system seems to be fine. The 52Amps looks fine. It won't be pulling 52A at anything but full throttle regardless of what GG thinks. Not sure where her theory says that it is pulled at all throttle positions.

Still a little puzzled about that crash. Were you running an Rx battery then, or did you have the BEC in use at that time? I wonder if it was overheated, how many servos do you have in the plane? Did you see where your LVC is set to?

Have fun. We'll have to get together again sometime to fly, I just finished up my Giles202 that I converted to E-power. Should be a fun little flyer.
Curtis

rc_man1

Very nice plane you have there!!! I'm still flying mine for a year now and it is one of my favarite planes to fly.. I have the building thread over at RCgroups.. [link=http://www.rcgroups.com/forums/showthread.php?t=669122&highlight=hog+bipe]Check it out[/link]Check it out

vmsguy

I was running a receiver battery on the maiden. I'm running 4 servos. 1 for each aileron, 1 rudder, 1 elevator. Ailerons are 3152s, a 3152 and a 9202 for rudder and elevator. I can't remember which did what.


Nope, not running the BEC.. Not ever... Never had it set up. Disabled it from the get-go.. whatever cliche you want to use.. (hee hee)


My best theory, is that the ESC overheated and shut down. I had it a little bit buried behind the motor. It's been moved for better airflow.
My Second theory is one of the batteries was faulty and died.
My Third theory, is that Mike was flying it harder than he thought he was, and overheated/maxed out the power without realizing it.

beau0090_99

Anything is possible. I have rerun that scene in me head a few times. It wasn't clear in the video that he lost power, but it looked like it stalled out of the sky. I wonder if it hit the LVC at the end and there was no time to reset it.
Let us know how round two goes.
C