speedy72vega

Well, it happened Sunday. I was making a banking pass by the runway with my Deuces Wild. It made a horrible screeching sound as it went by, as the right side motor quit. I tried all I could to keep it up in the air, and actually managed to get it turned downwind in an attempt to come around for a landing. As it came around for approach, it stalled and spiraled in.
It hit the ground in a thudding cartwheel, and all I could see was pieces flying up into the air. []
I started walking out to get it, when I noticed a pretty good cloud of smoke developing. I ran out to where it was, to find that the right ESC had exploded, and was burning. I unplugged the battery, and gathered up all the carnage.
I'm now in the process of rebuilding it, and will post progress pics if anyone's interested. I have loaded some pics of the damage, and will load some pics of the progress so far.

speedy72vega

More pics.

FallDownGoBoom

My Feedback: (1)

Bummer!

Good luck with the rebuild.

BEAR-AvHistory

Could you please give some info on the motors & ESC? What timming was set in the ESC?

speedy72vega

Thanks Fall, I will post as I progress.
Bear, I am running Turnigy Plush controllers, with Turnigy 42-50-650 motors on 5S 3000ma packs, one for each motor.
I disassembled the motor post-crash, and can't find a thing wrong with it. Magnets all ok, bearings smooth as silk. I'm pretty sure the problem was the controller.
I love the Plush series of controllers, can't be beat for the money IMHO, but I think I should have run a higher capacity controller. I was running Plush 40's. I didn't get more than 30-31 amps max at full throttle, so I figured they would be ok. I had about 14 flights on this setup before this happened, and all was great. Motors, controllers, and batteries all cool to the touch after flights. The controllers were set to medium timing.
When I rebuild it, I will be using 60 amp controllers for the added capacity.

BEAR-AvHistory

Thanks for the info, thought I recognized the ESC. [sm=what_smile.gif]

The reason I asked is one of the guys at the field, coincidently a 42-50 in a Fw-190 made a noise similar to what you described and froze on a low pass over the runway.

Turned out, we believe, that the ESC timing was set to low & the system crashed on a sudden power up from 1/8 throttle to WOT.

I run similar motors 42-60/500 on 5S but use 80amp plush units set to hi timing & so far so good. Not sure, but I have heard the the step up from 4S to 5S batteries is where these power packages get into trouble with timing.

speedy72vega

Mine seemed to run fine on medium timing up to this point, I had quite a few flights on it. I have run into those timing issues with the Super Simple controllers, just as you described, when getting back into the throttle. I had one burn up a motor on my Stinson on landing approach. I was able to land that plane with no problems, as I was already on glide. When I checked out the motor, all it would do was stutter back and forth, but not turn. I tried the ESC with a different motor and it worked, but I could hear a snapping sound at very low throttle position, and it would go away once I got about 1/4 throttle.
I don't use that controller on planes anymore, I just use it for my test stand now.

I suspect that the ESC was too small for my DW, even though I had 10 amps + to spare. I'm guessing at the higher voltage, 30 amps was too much. I had been running the plane at between 3/4 and 7/8 throttle for a bit right before the failure, and was pushing it a bit hard.
I am going with 60's this time around, hopefully i'll have better luck. I haven't tried running that motor again yet, but I couldn't find a single thing wrong with it visually after the crash, that's why I suspect the controller was at fault. The way it screeched, it sure sounded like a timing issue.

FallDownGoBoom

My Feedback: (1)

Speedy:

I'd think your Plush 40's would be plenty of ESC, especially since you've had several successful flights and are only pulling 30 amps. I run the Sentry line of Turnigy controller, not because I'm worried about monitoring the battery during flight but, at least in the case of the Sentry 40/60 amp controllers, the Hobbycity documentation says they use switching BEC's in stead of the Plush's linear BEC's. From what I've read, using a linear BEC with higher voltage batteries can lead to lower amounts of amperage going to the servos.

Which I freely admit doesn't sound like your screetching issue, but might also be a consideration with all the servos on a DW. I did play with the motor timing on my old Sentry with a smaller Rimfire motor. It didn't seem to make any difference in the power delivery. But with 5S batteries and a bigger motor, you could be on the right track.

Hope your rebuild is coming along.

Fred

BEAR-AvHistory

Meant to ask.

I have a Hangar 9 B-25J in a box that I hope to build this summer with E power most likely SK 42-60 or SK 50-55 motors. On your twin did you set-up for counter-rotating props?

speedy72vega

Fall, I'm running a separate rx battery, not the BEC's. I don't like to rely on the BEC in larger high voltage setups like this. The timing does seem to make huge differences in the larger outrunners. When I first put the DW together, I had test run one of the ESC's in a different plane, and had set the timing to medium. When I finally flew the Deuce, one of the controllers was put on 'out-of-the-box', the default is low timing. I completely forgot to set it to med. I had a 400-500ma difference in the batteries after a flight, consistently. Afther thinking about it for a bit, I realized my mistake. After resetting both to medium, the batteries were always within 40ma or so.

Bear, yes, I did set it up with counter-rotating props, 12X6E APC props. What size is the B25? I really want to build one!!!

I've made some progress on the DW, i'll post some pics as soon as I take some.

speedy72vega

Ok, here's some update pics. Lucky for me, the fuse broke in half very cleanly, right at the rear of the cockpit. I was able to repair it pretty easily, and I added some fiberglass reinforcement on the inside. The right wingtip is another story...........It was broken up pretty badly, and alot of the wood was missing. So far, I have pieced what was left back together, and will make the missing pieces from scratch. I am reinforcing the broken wing spars by laminating another piece alongside, after gluing them back together. Once I get the rest of the wing fixed and sheeted, i'll post some pics before I recover it.

I'm going to recreate the trim stripes with self stick covering once all the repairs are done.

speedy72vega

More pics. It won't let me upload more than 2 or 3 at a time for some reason.

BEAR-AvHistory

The repairs look like they are coming along fine..that's good to see. I know you will be happy to see it fly again.

The B-25 has 81" WS by 63" OAL. Should weigh about 13.5lbs ready to fly. They recommend a pair of Power 46 & a 60amp ESC so the SK42-60's on 80amp ESC's should be a good replacement. I am putting a little more power in because I like 3 bladed props on the warbirds.

The plane is probability the smallest of the all wood B-25 ARF's, but a smaller foam B-25 (53"WS) has just been released by Hobby Lobby

BEAR-AvHistory

Fred,

The Plush ESC's from 60amp up have switching BEC.

I use the HV 7.5amp UBEC spliced into the main battery circuit on anything running a 5Sxxxx battery. If the motor or ESC go down I still have the RX/servos powered & working to try to get the plane down in one piece.

FallDownGoBoom

My Feedback: (1)

Bear:

Thanks for correcting me. Should've done a better job on my homework, but the biggest ESC I've used is 60 amps. I have two of them, which ironically enough were destined for a possible Dueces Wild.

One of the guys at our field has the H9 B-25, although his is wet powered. Says it flies pretty well. I've got a Wing Mfg Mitchell about 1/2 built, and am thinking of going electric on it.

speedy72vega

I would love to see some pics of both of your B25's, I am really considering getting one.

BEAR-AvHistory

FDGB,

The Wing B-25 is a very nice plane, I am sure you will be very happy with it. [sm=thumbs_up.gif]

Speedy,

My B-25 is still in the box. Its an ARF & will look like this when done.

http://www.seabreezeparachutes.com/b...5-10-16-08.wmv

http://www.youtube.com/watch?v=n_XND31TvpU

speedy72vega

Man I souldn't have watched those videos!!!!!!!![:@] Now i'm going to have to figure out a way to get one! Awesome.

FallDownGoBoom

My Feedback: (1)

Bear:

I'm sure it will result in a nice plane... it's just the build process! Paraphrasing Wing's construction guide: "...now install the main gear and operating gear doors, if desired..." Wow, a month's work in only 11 words! OK, that's not fair to Dan at Wing Mfg: he's been very helpful, the kit goes together pretty well, and they warn you up front: it's not a beginners kit. But I wanted a B-25, and when I got it 4 years ago, neither the H9 or Topflite ARF's existed.

Let's assume I scrap the plan to power it with dino droppings and use electrons instead. It'd be fairly difficult to mount a single power source and pair of ESC's in the fuselage and run three wires from each ESC to its respective motor out in the wing, so I think I'd opt for something like a 5000mah 5S and 60/80 amp ESC in each nacelle. Just to keep things simple, I'd power the receiver with it's own 6V pack. Now's where I get hazy: do I run a Y-connector out of the rcvr's throttle port and plug an ESC into each side of the Y? If so, do I have to disable the power lead coming out of either/both ESC's?

From what I've read/seen, the "preferred" way to power multi-engine setups is a single power source wired in parallel to 2 ESC's, with the power lead on one ESC cut. That's not practical in this case, the wing's already built and I'm not sure there's enough room in the wiring tunnel to accomodate ESC/motor leads, retract tubing, and aileron servo extensions.

Got any ideas/guidance?

Thanks in advance,

Fred

flying pastor

Fred, on my electric dual ace I use a y-lead for the throttles and isolated the power wires from each 60a ESC. I use a seperate 4.8 v receiver pack. Some people parallel their main drive lipo's or use a larger single one but I have just used 2 lipos, one for each motor. I have used this without problems for 2 years. Just check that they both take about the same amount of charge and every so often taco each motor to check they are both running at approx the same revs.
Chris.....UK.

speedy72vega

Same here Fred, in my DW I run separate batteries for the motors, and a separate RX pack. Remove the red middle wires from the ESC connectors, and tape them back.
To connect the controllers to the RX, a Y lead from the throttle port to both ESC's is the most common way to do it. Some like to run them off of separate channels and then mix them using the radio. Up to you which method you prefer.

speedy72vega

By the way, i've almost got the fuselage completely done, all I have to do is finish the striping. I like the original paint scheme, so i'm recreating it out of trim covering. Only problem is, the red is bright, and I couldn't find an exact match, so you can see a difference in the color, but i'm ok with it.
I'll post some more pics as soon as the stripes are done.

BEAR-AvHistory

Agree. I am going with two batteries & Y leads for the throttle with the ESC red leads pulled out of the plug & shrink wrapped back. The H9 B-25J is tail heavy when set up for E power & some guys run the power batteries in tandem with the receiver battery tucked all the way up in the nose.

Thing is, with retracts it runs 10 servos so I was looking for a way to run a high voltage UBEC off the main battery/batteries & lose the receiver battery. Not being an electrical engineer [sm=confused.gif] my gut says I was have to draw power from both main batteries so that they deplete evenly & not have one engine go away on landing. Still doing some research on this.

speedy72vega

Bear, run a separate LiPo up front for the UBEC. That way, you don't have to worry about the motor batteries discharging unevenly. A 2S 2200 LiPo would weigh quite a bit less than a standard NiMH pack also.

Heres a few pics of the finished Fuselage!! I only have the Canopy and nose cone taped on temporarily for now, and the red I used is a shade darker than the original red, but it came out pretty fair all in all.

BEAR-AvHistory

Looking good, nice to see it back. Thanks for the info - will take a look at a separate Lipo for the UBEC, sounds like a clean solution that will kill two birds.

I am using 3S2550mah Lipo's in my TX, they are pretty small & light but the C rating is very low. 3C IIRC. Any thoughts on what C rate the UBEC would need?