Carl Goldberg (???) Giant Extra 330 Electric Conversion

[kyleservicetech]

An oldie but goodie, that Carl Goldberg ARF. I purchased this 77 inch wingspan, 1120 square inch model, brand new in the box from the Local Hobby Shop for $250 after it sat on their shelf for some five years. It was inspected at the Hobby shop before buying it.

After getting it home and really going over it, it looks to be a decent model. Power is going to be a 12S2P 2300 Mah A123 pack, 80 Amp HV ICE Castle Creations ESC, and a Hacker A60-6M motor with a 19X12 APC-E prop.

After assembling everything in the model, the first power run of the power system resulted in 6550 RPM, 68 Amperes, 34 Volts for 2300 Watts. That is with in 5% of the predicted value in www.motocalc.com.

The total weight, ready to fly comes out at exactly 17 pounds, resulting in a power level 135 Watts per pound, not to bad for a giant scale model.

Yes, Hacker only rates this motor at 45 Amps or so, but their own internet web page shows this motor running at similar power levels. This model could save perhaps a pound of weight by going to Lipos, but the zero fire hazard with A123 cells has some benefits.

Can't fly it now, Wisconsin got hit with a snow storm, so flights will be 3 - 4 months from now.

Take a look at the photos.

[kyleservicetech]

Originally Posted by kyleservicetech

.

Maiden Flight today.

I just got the first three flights on my Hacker A60-16M, 12S2P A123 pack, 19x12 APC-E prop, 78 inch wingspan, 1200 square inch Extra 330 model today.

Winds were about 12 MPH, temperature about 45 degrees.

Holy Crap, that motor has power! It hauls that 17 pound airplane up at 60 degrees and keeps on going. The Castle Creations ICE database shows that the maximum power is 2650 watts, turning that 19X12 prop at 6500 RPM. This setup had no problem flying the model running at about 600 watts while in flight. I limited my self to 4 minute flights, which took about 1300 Mah out of the batteries 4000 Mah capacity.

Maximum current pulled by that Hacker was 69.5 Amps, the motor was cold on landing. (It was only 45 degrees F though)

First flight was near disaster. Severe overcontrolling on elevator, using the recommended elevator travel. Got it back on the ground, corrected elevator travel and centering, and put two more flights on it. This really made a BIG difference, the model turned into a very nice to fly model.

This model now has 12 flights on it with mild acrobatics. Loops, rolls, spins, inverted flight, all no problem. Flights have been set to exactly 6 minutes, which pulls 2.4 Ampere Hours out of the 4.00 Ampere Hour 12S2P A123 battery pack. IMHO, its nice to have another 3 minutes flying time "Just in case", like if someone crashes on the field and you can't land.

[CHELLIE]

Congrats on the Successful Maiden Dennis

[Larry3215]

Nice job Denny!

If you ran 4 minutes and only used 1300 mahr you could almost drop down to 12S1P and save a couple of pounds. The increase in performance might be worth it. You should still be able to fly 6 minutes with some reserve.

Id put a bunch of flights on it first to get a better average of usage

[kyleservicetech]

Originally Posted by Larry3215

Nice job Denny!

If you ran 4 minutes and only used 1300 mahr you could almost drop down to 12S1P and save a couple of pounds. The increase in performance might be worth it. You should still be able to fly 6 minutes with some reserve.

Id put a bunch of flights on it first to get a better average of usage

Could do that, but running 70 amps through a 12S1P pack would really be loading down those A123 cells. Their voltage would drop to about 2.4 VDC at those currents. Per motocalc, that would also drop the power down from 2600 to about 1800 watts.

[kenchiroalpha]

Hi Dennis
Congratulations on the maiden
Shes quite sharp looking
May she bring you much joy in the years to come
Take care dear friend
Yours Hank

[kyleservicetech]

Originally Posted by kenchiroalpha

Hi Dennis
Congratulations on the maiden
Shes quite sharp looking
May she bring you much joy in the years to come
Take care dear friend
Yours Hank

Hi Hank
Thanks, it's appreciated. (Right now, its raining outside, and 44 degrees F. Guess no flying for awhile )

[kenchiroalpha]

Originally Posted by kyleservicetech

Hi Hank
Thanks, it's appreciated. (Right now, its raining outside, and 44 degrees F. Guess no flying for awhile )

Hi Dennis
Your most welcome
You need to get an micro indoor flyer or 2 or more
They surely take the edge off of a rainy day
Heres 2 examples, im able to fly them in as small a space as an 8 x 10 room
Take care dear friend
Yours Hank

[kyleservicetech]

Originally Posted by kenchiroalpha

Hi Dennis
Your most welcome
You need to get an micro indoor flyer or 2 or more
They surely take the edge off of a rainy day
Heres 2 examples, im able to fly them in as small a space as an 8 x 10 room
Take care dear friend
Yours Hank

Hi Hank
That thing looks interesting. Where can you buy it? That could be fun flying in my back yard.

Some of my club members that fly giant scale models also fly these things during our club meetings.

[Larry3215]

Originally Posted by kyleservicetech

Could do that, but running 70 amps through a 12S1P pack would really be loading down those A123 cells. Their voltage would drop to about 2.4 VDC at those currents. Per motocalc, that would also drop the power down from 2600 to about 1800 watts.

Good point. I ran into that same issue trying to use A123's in an edf project. To hold the voltage I needed to get the rpm I wanted required too many cells so I had to go back to lipo on that one.

[kyleservicetech]

Originally Posted by Larry3215

Good point. I ran into that same issue trying to use A123's in an edf project. To hold the voltage I needed to get the rpm I wanted required too many cells so I had to go back to lipo on that one.

Agreed, my experience those 2300 Mah A123 cells are best used at 30 amps or less per cell.

At any rate, IMHO those Lipos with the 45C ratings are a little questionable. Your flying time is 60 minutes divided by that "C" rating, so running any battery at a continuous 45 C gives you a flying time of 60/45 or 1.3 minutes That's only 80 seconds.

Of course that high "C" rating does suggest very low battery internal resistance for those brief full throttle surges.

[kenchiroalpha]

Originally Posted by kyleservicetech

Hi Hank
That thing looks interesting. Where can you buy it? That could be fun flying in my back yard.

Some of my club members that fly giant scale models also fly these things during our club meetings.

Hi Dennis
Sorry to say these 2 models are not in production anymore
Cant understand why as they are wonderful aircraft
Check out these
http://www.hobbyking.com/hobbyking/s...dProduct=11038
http://www.hobbyking.com/hobbyking/s...dProduct=10457
And these sites
http://www.indoorflyingmodel.com/index.html
http://smallflyingarts.com/
http://aerofred.com/
http://www.microflight.com/
If you have any questions pm me
Take care dear friend
Yours Hank

[kyleservicetech]

Originally Posted by kenchiroalpha

Hi Dennis
Sorry to say these 2 models are not in production anymore
Cant understand why as they are wonderful aircraft

Thank Hank
I'll be looking at these down the road.

Have a good day!