fockewulf37

My Feedback: (102)

Well I guess I have been bitten by the electric bug. I am converting my Wellington to Electric. I have been flying it om Zenoah G-26 motors and it really been over powered. So After My 109 did so well I decided to change my Wellington electric. Lipos are so expensive I decided to try the A123 Batteries. I have been taking a crash course on the A123 Batteries and hope I am up to speed.

The Wellington weighed 31 LBS dry before. Each Motor weighed 4 lbs with muffler and then I had 16 oz tanks which would bring the take off weight to 5 lbs each side. The total weight of the electric power system is going to be 5.7lbs each side. That is a reasonable increase.

I plan on using 2 Eflite 110's for power and 2 10s1p packs per side

I had a chance to run the Eflite 110. I am using an 18x6 APC wide blade. There are many different props but I am use to using this on on my 3 cylinder radials. On the Saito 170 I turn about 7400 rpm with this 18x6 prop. With the 110 I am able to turn about 7200 rpm for an intial burts for about 1 minute . The Wellington has a light wing loading in my opnion. So 7200 is more than enough for takeoff. Well I was able to run the 110 with 2 sets of Batteries in pararell and get a 12 mintue run time.

I was averaging 6000rpm with frequent burst to 6900 rpms throughout the run except for the last 2 minutes the burst were to about 6000-6500...

This is plenty of power for the Wellington. almost no vibration and no holes needed in the cowls.. I really like this set up and can wait to fly it...

jumper666

A video of its flying would be interesting.

fockewulf37

My Feedback: (102)

Here is one of it with gas...I'll take another when I fly it on electric power...

http://rcuvideos.com/item/KSG9MH0TWHC05B2S

ty

normgoyer

Great looking model and make sure that you have a Li-Ion dedicated charger. I also use A 123 M-1 cells and I have a Li Ion Astro 109 to get a proper charge into them. A regular Astro 109 won't work, it undercharges them. Norm

fockewulf37

My Feedback: (102)

Norm,

Thanks for the comments,

I am Using a Zip line to charge right now but I plan to go to a Astroflight 112D and maybe use the Dapter from SLK.

Ty

MBLAKECC

NICE PLANE AND VIDEO. CAN YOU FLY IT CLOSER TO GROUND NEXT TIME? DO YOU HAVE A WAY OF CHARGING THE MAIN BATTERES WHILE THERE IN THE PLANE.

fockewulf37

My Feedback: (102)

I do touch and goes with the gear up. Its really a stable platform. I usually have to recover the bombay doors after each meet i go to... Its not a scale maneuver but its fun..

Ty

fockewulf37

My Feedback: (102)

I am still working on my final set up. I should be able to reach in the cowl and charge directly in the plane. I am also makeing the motor where it comes off very easily. So if I ned to get to theebatteries It can be done in just minutes...
3 wing nuts and the motor is off....
Ty

fockewulf37

My Feedback: (102)

I just finished up my 4 10S packs for my Wellington I am converting to electric. I even added 2 sets of balancing plugs so I could balance using a Astro flight 123 blinky. It appears to work really well. Also I am using the Astroflight 112D charger and it charges well...I made my balancing plug using standard male plugs from MPI and also 22 gauge servo wire.

Here are my pic's

Ty

fockewulf37

My Feedback: (102)

sorry double posted

didiwatt

My Feedback: (38)

Ty:
Since you have been "bitten", I would suggest a couple things. You did not say what size of speed controller you are using?

I would suggest that you put a "Watts UP" meter between your speed controller and battery source to determing exactly what is going on. It will show maximum amps pulled so you can determine that you speed controller is adequate. It also tells you the watts you are putting out which is extremely important. And also shows the mah's used which determines how long you can fly to keep from using more than the recommended 80% of available mah's.

In my opinion you need 100 watts per pound to "sport fly". If you look at the E-flight information on the 110, it is capable of 2000 watts x 2 motors equals 4000 watts divided by say 35lbs of airplane get you 114 watts per pound which is more than enough.

The key to the E-flight information is "capable of". You still would be wise to find out exactly how many watts you are putting out with "your set-up". With a meter you can play with different props and number of cells to get the efficiency needed.

Another thing to consider is using a single power source for both motors. All battery packs do not drain equally causing rpm difference between the motors, paticularly should you happen to be end up getting into the last 20% of battery mah's .

Using a single source elimates this problem. Even using 4 packs, you can series 2 sets and then parralel them. I saw your build thread on this plane which was excellent but I can't remember is you had room in the fuselage for such an arrangement.

I am working on a 140" AeroCommander now and am considering going to electric. Estimated weight is in the 40 to 50lb range so I am doing all the calculations.

Hoped this helped.............
Paul

fockewulf37

My Feedback: (102)

Paul,
Thanks for the info.
I have tested the setup. I am using a CC 85 HV. I an pulling about about 1500 watts at full throttle and about 45amps. With the G-26's the plane was way over powered. So now I am able to turn a 18x6 at about 6900 rpms and that is plenty for this plane. I am still planning on keeping the batteries seperated. One set per motor. I've flown twins for a good while and rpm differences for up to 500-700 rpms really does not make much difference to me .
I plans on keeping my flight time down to about 6-7 minutes and that should give me a good cushion for power...If this one works out well I may do my Savoia Marchetti S79 with electrics....

Thanks Ty

fockewulf37

My Feedback: (102)

The thrust calculator says I should have about 12.5 lbs of thrust at 6500 rpms and I know I can hold that for the 7 minutes I plan to fly plane . With a burst to 7000 rpm's i would have 14.25 lbs of thrust per motor. I would be just under 1:1 Thrust for the plane...

ty

didiwatt

My Feedback: (38)

Great, you did your homework. That calculates to about 86 watts per pound. I will await with anticipation to see what you think.

By the way, what is your wing loading?

Here is a picture of a 337 I am just finishing up on. DA-50's. Wing loading =58oz. uuuugggghhhh..... wish it were lower.

Best of luck
Paul

normgoyer

Hi Paul, that is a Cessna 336. The 337 had retractable gears, the 336 was the first one they built and it was not succwssful due to the fixed gear. So they changed it. All of the military ones were 337 configured for military use. In civilian life the 337 was changed many times to turbo charged engines and even a pressurized conversion. Norm

didiwatt

My Feedback: (38)

Norm, yes you are right. Slip of the keyboard. Thanks

fockewulf37

My Feedback: (102)

Paul great looking Cessna. The Wellington has 2112 square Inches . It is mostly a flat bottom airfoil and I am still at about 32lbs for the weight... So doesn't that put my wing loading about 35oz ??

Ty

didiwatt

My Feedback: (38)

Well, lets see. The constant is 2304. So 32lbs x 2304 = 73728 then 73728 divided by 2112 square inches = 34.91 oz.

This is very low for twins, you lucky dog. No wonder it flies so nice and predictable. I have seen P-38's at 80 ozs. and still fly. (very fast though) From what I have read, 50 0zs is normal for twins.........

Paul

fockewulf37

My Feedback: (102)

I ran the Wellington yesterday for the first time with both motors. here is the video:

http://www.youtube.com/watch?v=3F7NL3YsP-Q

Ty

feathermerchant

That looks great. I have run the Castle 45HV to 65A in bursts. No problems. Be careful running long periods of time in the ground. The system is most stressed at WOT sitting still. Things may get hot but probably not in Canada this time of year. Good luck and be sure to shoot us a video.

fockewulf37

My Feedback: (102)

Here is the first video of my Wellington's first flight on the E-flite 110's and A123 Batteries. Great power and could easily get a 10 minute flight...

http://www.youtube.com/watch?v=xst-WJjlONc

fockewulf37

My Feedback: (102)

Hey everyone,
I just got back from the SEFF meet yesterday. I had a great time. I was able to fly the Wellington about 12 or more time over the four days. My flights averaged 8 minutes and when I went back to charge the batteries I was replacing about 2700 mahs per set of batteries (20 cells) . I was cahrging with my Astro flight D112 charger and it took about 25 minutes per nacelle at about 6 amp rate....

Ty