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Old Oct 16, 2010, 08:49 AM
Flick lives
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beautiful, picturesque Southern New Jersey, USA
Joined Dec 2008
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Originally Posted by markarch View Post
Burt,
I hear ya. Believe me. I trust your experience. I have not flown mine since I last posted about my issue. I just pop in here now and then to stay updated. I have quite a few projects going on so I have not done the true testing that this plane deserves to sort out this issue. I only have two 30 am escs available at the moment so my plan is to order a couple 40 amp versions to test them out. I like this plane so much that it is not worth risking until I get it worked out.

By the way. I LOVE your latest creation. It is beautiful. I may need to pick up a spare airframe to do a scheme just like it.
Good, don't prang that great looking plane...It's such a temptation to go and fly it, even when you know it's acting sketchy.

Thanks about my C-47...I have yet to maiden her! I went to do it last weekend but my flying field was loaded with people having some kind of Autumn extravaganza. Today, its 40kt wind gusts. In the mean time, I've done a couple more tweaks on it. I did brendon h's battery hatch push-rod mod and that works really well. I also elected to enhance the cowl flaps by outlining them with a black paint pen. My static motor tests have been encouraging. First of all, I noticed when I plug in the lipo, both ESC's beep in tandem. In my (crashed) model #1, only the left ESC beeped on start-up. Also, the motors seem to be in sync with each other at all throttle settings. I think this is one Skybus that didn't roll out of the factory on a Friday afternoon.
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Old Oct 16, 2010, 09:05 AM
Flick lives
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beautiful, picturesque Southern New Jersey, USA
Joined Dec 2008
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Originally Posted by Tamilflyer150 View Post
Heres a new flight video of my Dynam Skybus.

Thanks for posting your vid, Tamilflyer150, it's good to see video of a Skybus actually taking off, flying well and landing without mishap.

I liked your judgment in using the go-around, and not trying to "save it" and just land like many RC pilots and some pilots with full-size airplanes strapped to them will elect to do. This really comes in handy when flying foam models that can be buffeted around by a gust of wind just prior to touch down...I always try to leave enough battery for a go-around and another shot at some smooth air.

I see your excellent battery ventilation mod also makes good finger holds to pull that hatch off. You could also try gluing in a square of nylon window screen to make them a better match with the decal windows.
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Old Oct 16, 2010, 11:34 AM
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Quote:
Originally Posted by markarch View Post
Burt,
I hear ya. Believe me. I trust your experience. I have not flown mine since I last posted about my issue. I just pop in here now and then to stay updated. I have quite a few projects going on so I have not done the true testing that this plane deserves to sort out this issue. I only have two 30 am escs available at the moment so my plan is to order a couple 40 amp versions to test them out. I like this plane so much that it is not worth risking until I get it worked out.

By the way. I LOVE your latest creation. It is beautiful. I may need to pick up a spare airframe to do a scheme just like it.
30 amp ESCs should be more than enough. I measure 13.6 amps wot draw per motor on a fresh battery with the stock props.
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Old Oct 16, 2010, 12:46 PM
The figure "9" Specialist
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A Barrier Island in New Jersey, USA
Joined Oct 2003
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Originally Posted by rperego View Post
30 amp ESCs should be more than enough. I measure 13.6 amps wot draw per motor on a fresh battery with the stock props.
WOW!, that's a lot lower than I would have imagined! I haven't built mine yet (yeah, I broke down and bought one) but I was thinking of going with a pair of CC Phoenix 36's I have laying around - if they fit. I guess I'll re-think that since the two Phoenix ESC's can easily be used in one of my SC conversions as well as an old Super Star conversion that's next.

Aeronca
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Old Oct 16, 2010, 01:33 PM
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Originally Posted by aeronca View Post
WOW!, that's a lot lower than I would have imagined! I haven't built mine yet (yeah, I broke down and bought one) but I was thinking of going with a pair of CC Phoenix 36's I have laying around - if they fit. I guess I'll re-think that since the two Phoenix ESC's can easily be used in one of my SC conversions as well as an old Super Star conversion that's next.

Aeronca
Be careful if those ESCs have switching BECs that you don't let both of them power the RX. If your's are the 3amp version, you're in good shape wiring just one to the RX.

I asked earlier about the stock wiring harness that lets both BECs power the RX. Since then I found many folks think usually linear BECs can be paralleled. I ran a test using Dimension Engineering's "Servo Sense" (now sold to Common Sense RC) and found that the stock ESC BECs in parallel in fact share the load - or at least it appears that way. A test of 2 servos being worked showed a total of .5 amps peak draw when measured in total, and .2 and .3 amps when measured individually. The Servo Sense "average" and "15 sec. average" readings also indicated the BECs were sharing the load.

That said, even the Servo Sense peak draw is derived from an average of 50 samples so it's conceivable the max draw on one side could have been higher for a very short time, hence dragging the voltage down and causing the other BEC to take over.

When I spoke with Dimension about the vailidity of my test, they mentioned that although these BECs appear to "play well together", they've found some linear BECs that don't.
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Old Oct 16, 2010, 03:01 PM
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Orange County, Ca.
Joined Jan 2009
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Finally got the 3 Blade props on it, can't wait to fly it and see if theres any difference. I'm sure the performance will drop a bit. These are GWS 7x3.5x3.

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Old Oct 17, 2010, 09:20 AM
Flick lives
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beautiful, picturesque Southern New Jersey, USA
Joined Dec 2008
473 Posts
Maiden

Maiden flight...Once again, a complete exercise in frustration. The airplane taxies beautifully with the steerable tailwheel, but as soon as I give it some throttle it cuts to the right and does the Skybus tail-chase. I checked the tightness of the props and did the ESC sync, but no difference. I tried holding the tail down during the takeoff roll with some up-elevator, used rudder, etc.

Finally, the little voice in my head said STOP! And I did. Just like I've been telling everyone in here who says they have this problem.

So, I don't know what I'm going to do next...Probably hangar it and cool off a while. I don't think I want to mess with these Dynam(n) motors and ESC's at all...I'm just not that confident in my soldering skills to get new electronics and make a new wiring harness. I'm pretty much dead in the water.

That's it...I'm going to have another coffee and sit down with the Sunday newspaper.

Burt
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Old Oct 17, 2010, 09:25 AM
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If you don't feel confident enough to do the soldering, maybe there is a club nearby with someone who is willing to do it for a fee or for free. Otherwise, check the yellow pages for computer or other repairs and find someone who will do it for a fee.

I've seen one of these fly, and it is a thing of beauty!
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Old Oct 17, 2010, 10:02 AM
The figure "9" Specialist
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A Barrier Island in New Jersey, USA
Joined Oct 2003
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Quote:
Originally Posted by BladeHead View Post
Maiden flight...Once again, a complete exercise in frustration. The airplane taxies beautifully with the steerable tailwheel, but as soon as I give it some throttle it cuts to the right and does the Skybus tail-chase. I checked the tightness of the props and did the ESC sync, but no difference. I tried holding the tail down during the takeoff roll with some up-elevator, used rudder, etc.

Finally, the little voice in my head said STOP! And I did. Just like I've been telling everyone in here who says they have this problem.

So, I don't know what I'm going to do next...Probably hangar it and cool off a while. I don't think I want to mess with these Dynam(n) motors and ESC's at all...I'm just not that confident in my soldering skills to get new electronics and make a new wiring harness. I'm pretty much dead in the water.

That's it...I'm going to have another coffee and sit down with the Sunday newspaper.

Burt
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What a bummer!, but you did the right thing to STOP! Not that many people take their own advice! Maybe over the winter you can practice your soldering. Good soldering is not difficult, it is a skill learned fairly quickly that comes with some practice. I know you can do it, but for now, just let it be.

Unfortunately, your experience really has me leaning towards building mine with after-market motors and ESC's. Too bad I bought it BEFORE they offered it as an ARF, so to speak, but since I've not started anything with it yet I plan to really test out the motors and ESC's before I make up my mind about using after-market items. A real shame that some of these Skybus RTF's are "good-to-go" right out of the box while others are subjected to what you just experienced. I am truly glad you stopped, as you have one BEAUTIFUL C-47! Chill out, have a cup of coffee for me, then logical thought shall return.

Aeronca
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Old Oct 17, 2010, 10:42 AM
Vanadu
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Canada, YT, Whitehorse
Joined Dec 2008
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Quote:
Originally Posted by BladeHead View Post
Maiden flight...Once again, a complete exercise in frustration. The airplane taxies beautifully with the steerable tailwheel, but as soon as I give it some throttle it cuts to the right and does the Skybus tail-chase. I checked the tightness of the props and did the ESC sync, but no difference. I tried holding the tail down during the takeoff roll with some up-elevator, used rudder, etc.

Finally, the little voice in my head said STOP! And I did. Just like I've been telling everyone in here who says they have this problem.

So, I don't know what I'm going to do next...Probably hangar it and cool off a while. I don't think I want to mess with these Dynam(n) motors and ESC's at all...I'm just not that confident in my soldering skills to get new electronics and make a new wiring harness. I'm pretty much dead in the water.

That's it...I'm going to have another coffee and sit down with the Sunday newspaper.

Burt
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Good call on not sending it up, that's the mark of a wise man

Why don't you get wiring and practice your soldering. It really isn't that hard; flux is great stuff too! It's like a magnet for the solder. You could solder wires together for hits and giggles or you could solder an LED light circuit of a sort.

Take your time, go for it! You've done a really nice job on your plane. Go fly something else to fill the void, that's what I do in these situations.
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Old Oct 17, 2010, 10:43 AM
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O.K., here's the deal: I'm on the West coast, and retired. If you want to take the time, I'll solder it for you free. All I need are the specifications.
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Old Oct 17, 2010, 10:55 AM
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Originally Posted by angelfood View Post
O.K., here's the deal: I'm on the West coast, and retired. If you want to take the time, I'll solder it for you free. All I need are the specifications.
His location says, "New Jersey". Nebraska would be meeting in the middle.
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Old Oct 17, 2010, 11:14 AM
The figure "9" Specialist
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A Barrier Island in New Jersey, USA
Joined Oct 2003
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Originally Posted by angelfood View Post
O.K., here's the deal: I'm on the West coast, and retired. If you want to take the time, I'll solder it for you free. All I need are the specifications.
That is really very nice of you, and I am sure there are others willing to make the same offer - that's what's great about this forum. However, IMHO I believe it is in BladeHead's best interest to let him learn to fish than to give him a fish. No offense meant, but sooner or later in this hobby, conquering the task of soldering is a MUST, and it really isn't that difficult to learn. BladeHead obviously has fantastic modeling skills and I KNOW he will be able to solder with proficiency with some practice.

Aeronca
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Old Oct 17, 2010, 11:26 AM
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Bladehead - couple of suggestions:

Do you have a LHS or flying club where someone can help you learn to solder? Or, try web instruction videos.

Have you determined by swapping the motors around whether it's the motor or ESC causing the problem? Any chance you have one prop on backwards?

Even an inexpensive tach is worth having - like http://www.hobbycity.com/hobbyking/s...dProduct=10783

Also, cheap to build is a thrust stand. These are invaluable for playing around with different props. Mine, pictured here is shown with the motor mounter as a pusher, which Dr. KIWI thinks is a little more accurate than a tractor mount. Another type is even easier to build where the whole affair sits on the scale with the motor trying to push it towards the scale.
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Old Oct 17, 2010, 01:48 PM
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Hemet,CA
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Quote:
Originally Posted by BladeHead View Post
Maiden flight...Once again, a complete exercise in frustration. The airplane taxies beautifully with the steerable tailwheel, but as soon as I give it some throttle it cuts to the right and does the Skybus tail-chase. I checked the tightness of the props and did the ESC sync, but no difference. I tried holding the tail down during the takeoff roll with some up-elevator, used rudder, etc.

Finally, the little voice in my head said STOP! And I did. Just like I've been telling everyone in here who says they have this problem.

So, I don't know what I'm going to do next...Probably hangar it and cool off a while. I don't think I want to mess with these Dynam(n) motors and ESC's at all...I'm just not that confident in my soldering skills to get new electronics and make a new wiring harness. I'm pretty much dead in the water.

That's it...I'm going to have another coffee and sit down with the Sunday newspaper.

Burt
Attachment 3540494
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Dang you guys sure do jump to conclusion quickly, didn't you guys ever think that perhaps the esc programming is off or in a wrong mode?
Well i just made this video, the issue that Bladehead and all the others are having are most likely that their ESC's may have been accidently put into High Timing which isn't good you want to have Low timing. And after i made that video i once more programmed the esc's into high timing to see what they would do at full throttle and yes it seems like the left motor starts up and spools up quicker than than the right which is probably what makes your planes yaw to the right on takeoff.
http://www.youtube.com/watch?v=b3LK3sWhSSQ
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