Dynaflight Super Decathlon giant scale

[Art Horne]

Just finished my electric conversion of Dynaflights Super Decathlon. WS is 89", Weight with batteries RTF is 14lbs. With APC18X8E prop, AXI5320/28 motor, Phoenix CC HV85 ESC, and 10S1P Tanic packs lipoly (5000MAH) it pulls 45 amps at about 1800 watts and it is SWEET! Only one flight on it so far but only minor changes needed. Added some down thrust, aileron to rudder coupling and a little more throw on the ailerons and rudder. My first giant scale. The rolls are so pretty. I'll attach a few photos.

Regards,

Art

[Larry3215]

Nice!

How do you get to the packs?

Larry

[Art Horne]

Hi Larry,

Piece of cake. The batteries are right behind the firewall, and the windshield and the top of the fuse from the cowling back to the instrument panel is all one piece and is removable. The front edge of that fits under the rear edge of the cowling. The batteries all fit crosswise in the nose. They are actually three packs, two 3-cell and one 4-cell connected in series with Sermos connectors. They had to go there to get it to balance. The cabin space is all empty.

Hope that helps. If not clear I could take some more pictures.

Regards,

Art

[Art Horne]

Hi again, Larry.

Just noticed that you live in Gig Harbor. I used to live in Auburn, Woodinville, and Everett. I sold a car to a guy in Gig Harbor. Have you ever seen a black Jaguar XJS with real wide flared fenders running around there? I sold it around 1990 and I know it was there for a while.

Just curious.

Art

[Larry3215]

That sounds like an easy install Art. Sometimes battery placement and access are the trickiest things about a conversion!

Dont recall any black Jags in particular Art, but Im not into cars so I probably wouldnt have noticed one even if it parked next door :)

Larry

[Art Horne]

Here's a couple more pictures to show the battery access.

[8kasl]

Art,Beautiful Decathlon!That's the most sensible way to access batts I've ever seen---so simple and easy.Can you get some video of it flying?
Rich

[Art Horne]

Hi Rich,

Sorry, but I don't have a video camera. I got some time on it yesterday. It really flies nice. It's so big I can easily see it even when it is a long ways out. I flew it for 3 five minute flights. I'm recharging now to see how many MAH's it took. I flew most of the time at half throttle as it didn't need more for good performance. I used 3900 MAH out of 5000.
Regards,

Art

[8kasl]

Sounds like you timed the flight and throttle management just right.
Rich

[Greg D]

I had that kit all framed up a couple years ago with a converted Ryobi on the nose, sold it. I wondered about an E conversion while I was building it, thought it was too heavy. The reason I sold it unfinished , it was the only non E power plane I had. You did a great job on it!

[hermperez]

Art, was thinking of getting one of these. How did you place the components for it to balance?, there are some notes in the manual regarding servo placement to balance a large gas engine.

Did you build stock?, any changes?, how did you mount the motor?

and finally, how is the performace at 1800watts?, good vertical?.. get ready for more questions :)

[Art Horne]

Hi Hermperez,
Balance wasn't a big problem. The rudder and elevator servo went in as shown in the plans, however, they were GWS2MGBB small sized servos. They have 75 oz-in torque and are lighter than the full size ones. The aileron servos were the same. The battery was made up of two 3-cell packs and one 4-cell pack connected in series. They were Tannic 5000 mah packs. They were a tight fit placed crossways up against the firewall. There was almost nothing located in the cabin area of the plane. The CC Phoenix85HV was located under the box the motor bolted to. Total weight was 14 lbs, ready to fly. To mount the motor I made a cube out of 1/8th. inch plywood and bolted that to the firewall and then bolted the motor to the box. The box was about 3" on a side. It got a little tight next to the cowling and I had to round off the two front upper corners of the box. The box was needed to space the motor far enough forward to fit the cowl.

Unfortunately, I let it get too far out last week and lost orientation and put it straight into the ground. Lost one cell of the battery, the speed control and the airframe. The servos, motor, receiver and most of the battery were ok. After seeing the battery codition after the crash I wouldn't mount them crossways if I were to do it again. They stayed attached to the board they were strapped to but they were pretty badly distorted by the G-forces at impact. I removed the one dead cell (it didn't die for 2 days) and watched all the cells very carefully for several days before I tried to charge them. I charged them outdoors the first time. All surviving cells are still perfectly matched, both before charging and after. I have always charged my packs at 1/2C and never discharge over 9C and they are rated to 20C. I've flown then in another plane since the crash with no problems. I will check them before every charge for balance to be sure nothing is unbalanced. None of the cells were punctured and there was no smell of a ruptured pack.

Hope you have better luck.

Regards,

Art

[hermperez]

sorry about that Art, no plans to rebuild?

[Larry3215]

deleted - see my blog
Larry

[Art Horne]

Nothing left to rebuild. It went straight in. Already got a reply from CC that it was not under waranty and it's $70 to replace it. I went ahead and did that. I've got two other HV85's so it isn't stopping me from flying others.

Thanks for the sympathy.

Art