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Old Jul 07, 2012, 10:17 PM
115 inches of 'hog
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Can't wait to see it fly Ed!!!
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Old Jul 08, 2012, 07:31 AM
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Got some more stuff done on the plane yesterday. Got all of the servos in and wired to the power distribution panel. Will finish wiring the esc to battery stuff today. Hope to have the radio programmed this afternoon and maybe do an engine runup/test this afternoon.

I had to order replacement air cylinders for the retracts as the ones I have are quite old and the "O" rings are leaking. I am a little disappointed that the retract cylinders ONLY lasted 18 years Ordered new cylinders on Friday from Clippard. Hope to have them by Friday.

Included a photo of the wiring. View is from LE of wing looking aft. I put all of the servo leads in the blue 3/8" dia. wire loom to protect them and to add some "bling"

Ed
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Old Jul 09, 2012, 03:03 PM
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Progress Update

Thought I would update the thread on the status of the Harel A-10. Got everything installed and the AUW of the plane is 54 lbs (with batts). Ran the fans (tail pipes were not installed) and here is what I got:

Rt. Eng:
RPM 26446 4300 watts 98 amps 44 volts (stabilized) this motor is brand new and this was the first run on it so I hope it will break in shortly

Lt. Eng:
RPM 26723 4500 watts 104 amps 44 volts (stabilized) this motor has 40 flts on it in my Falcon 120

Balanced the plane at 20% of MAC (this is apparently where I had it balanced previously)

Let me explain the photos
The plane will not fit in my truck so I decided I will tie it down to the top of my 280ZX and transport it to the field. My support vehicle (with batteries/generator for the chargers/etc.) will accompany me to the field.

The handsome guy in the second photo is me, however I am not that that plump ( I look that way because I am trying to keep the plane from falling over)

Expecting new higher capacity batteries and the retract cylinders this week so if I get them in time, I will maiden the plane on the weekend

Ed
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Old Jul 09, 2012, 04:35 PM
Pursuit of Happiness
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Brentwood, California
Joined Jul 2007
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that's a bid bird!! looks cool

even at 9000 watts and 54 pounds your talking 160 watts per pound.... it's going to fly but I think it may be hurting for power a bit.

lucky the A-10 has a huge wing so it may do fine.... good luck with her and I hope it goes great
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Old Jul 09, 2012, 04:54 PM
Dean
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USA, CO, Littleton
Joined Apr 2005
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Around 2000+ square inches...

It has flown on a single Dynamax-OS. 91 when one engine quit in the air. 8-10 pounds of thrust.
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Old Jul 09, 2012, 05:18 PM
EDF rules... :)
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She's big....

Good luck on the maiden.

Eric B.
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Old Jul 09, 2012, 07:41 PM
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Ron:

Dean is right. When I was flying it, I had an engine failure and it flew single engine(kinda) well enough to get it on the ground. On Dynamax/OS 91 combos it flew on between 16 and 20 lbs of thrust (total) and the EDF configuration is putting out 29 lbs so I think it should fly better. Eric is correct, it has about 2200 sq. inches and lands very easily. My hope is that with 50% more power and at the same weight as it flew with the glow system, it should fly better.We shall see.

I will keep all posted.

Ed
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Old Jul 10, 2012, 01:43 AM
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You will be closer to 10k watts once you get the thrust tubes on, I'd go 3 3/8".
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Old Jul 10, 2012, 01:48 AM
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Ed what batteries are you running now?? On 30c 5800's I get around 5000-5100 watts. 40c 5000 I'm over 5300 and 25c 8000 I am at 5700. I don't trust the motors at over 5300 but that's me. If your going to really push the scorpion you should use a temp gun to figure out what temps you are hitting. Back of the motor should be 130 or less to be safe (160 she is toast).

Thrust tube and the right batteries it's going to be a nice setup!
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Old Jul 10, 2012, 08:25 AM
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bri:
I believe you are correct in that with thrust tubes and in flight the power should go up a little. My inclination is to go with the setup I have on my Falcon 120 which is tail pipe exhaust diamater of about 3.75". I found this setup to give about 14.5 lbs of thrust. Nice thing about the A-10 is the ease of access to the fans and nacelles. I am prepared to make a few different diamater tailpipes (with different exhaust outlet diamaters) and try them on the plane for evaluation.

Currently, I am using Skylipo 5000 mah 30C packs. I have tried to order some Gens Ace but the 5300 are never in stock so last week I ordered some Turnigy 6000 mah 70C nanotechs. THey were in the U.S. warehouse but the clowns at HK have still not shipped them. I thought that buying from the U.S. warehouse would be quicker but my order from HK in China shipped sooner than the stuff from the U.S. warehouse. Go figgure?

The 40 flights I put on the Falcon 120 with this setup showed that the highest motor temp was 119* right after the flight (used IR temp unit and measured at the back of the motor). The ESC temps were always below about 120* and the batteries got above 125* only one time.

I think the motor and ESC temps will be OK. My only concern is to watch the batteries closely since they are deep inside the fuse and I have some rather long batt to ESC leads. I did install the Castle cap packs per their recommendations so I believe that I should be OK. The +/- cables from the ESC to the batteries are in the order of 36" so I ran 8 gauge high strand count cables from the Batts to the ESC to reduce the voltage drop and lower the resistance. Ripple on the left eng was 0.21 volts and ripple on the right engine was 0.14 volts so I think I am OK.

We shall see. The true test will be this Saturday when I fly it.

Ed
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Old Jul 10, 2012, 09:22 AM
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Ed,

Your motor temps are good and hot days be sure to do a little cool down.

I'm concerned about your battery choice. The nanotechs are pretty strong, my 25c 8000 batteries are nanotechs and I think the power is a bit to much for the motor. I have only had about 4 flights in my falcon with those batteries, the temps on the back of the motor were 130 on a cool day, the batteries were brand new and not broken in yet. My other Turnigy's went up about 300 watts after about 8 flights and I was worried about that with the nanotechs cause I would be at around 6000 watts which is just to much for that motor.

If you go nanotech I would rethink the C rating and consider ordering something in the 20c rating to not over power the motor. I feel that the 30c 5300 Zippy's are ideal for the scorpion cause the provide good flight time yet keep the watts around 5000 which the motor can run at all day long.

That sucks about the order issue, I've ordered lots off batteries from the us warehouse and I always get them within one week.

Not trying to discourage you on the batteries but after seeing what the 20c 8000 nanotechs could do I was bummed that they were just to strong for that motor.
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Old Jul 10, 2012, 10:38 AM
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how many cap packs did they recommend for 36" batt leads?..... I would think two or three
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Old Jul 10, 2012, 11:23 AM
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bri:

Thanks for the feedback. I will consider your recommendations on the batteries. My feelings are that the motor will be OK. At full power on this combo with the Skylipo's I have pulled 117 amps @ 5100 watts for a few seconds and all of the numbers looked good with regards to amps, temps. etc.

I am of the belief that while batteries with higher C ratings can produce more power than one might need or the motor might "like/tolerate" I will try to keep the motor out of the danger zone. One of my concerns is that with very long battery cable lengths, I could not afford to have some marginally capable batteries that could not keep up with the esc/motor demands and cost me an ESC or motor. Because of this concern I went with some batteries that I believe can keep up with the demand (higher capacity and higher C rating). I certainly don't know if this is the correct decision but it is the one I made so I will have to see how things go.I understand your concern and I appreciate you input. My plan is to take the laptop to the field and download the castle link info after the flight and see if it looks like I am heading for trouble.

I have had the Turnigy 5000 mah 20C packs and they lasted about five flights before they got hot and began to fail. Battery temps were 129* on the last flight. In fact, one of the batteries split a cell and began to spew the chemicals inside the Falcon fuse. These Turnigy batts were not used hard and were from my pattern plane stuff. In my pattern planes I usually pull no more than 70 amps on full throttle and usually fly at about 55 amps so the batteries were not abused. However, in the EDF I think I was asking for more than they could provide. Even though some folks have had good success with the standard Turnigy batts, I am not a fan of them for my EDF stuff. Consequently, I tried the Skylipo 30C packs ( I currently have about 32 3S and 4S Skylipo packs) and have been happy with them but I wanted more capacity for longer flight times (something above the 5000 available thru Skylipo) so I looked at Gens Ace. When the Gens Ace were unavailable, I decided to try the Nanotechs.

I certainly do not proffess to have all (I probably only have a few) of the answers but I am always learning and I suspect that the learing curve will get a little steeper onthis project. Don't mean to offend anyone or start any heated debates about my choices but I made the choices I thought were right at the time so I will just have to see how things work out.

As I said before, I appreciate all of the input and I will give it consideration.

Thanks,
Ed
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Old Jul 10, 2012, 11:29 AM
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2 should be good since they are rated for 18"s. Ed if you are not aware there is a little formula you should be using to check the ripple and confirm its correct, it is no as simple as looking at the ripple in the data, you need to do a simple short ground flight sim then box the data for just the sim flight then take the AVG Volt divided by the AVG Ripple (or vise versa cant remember off of the top of my head) but it shoudl result in a number like .02 etc.. if you are getting .05 or higher you need better batteries or another cap. If the batteries are new and you are over .05 then you need another cap but if the batteries are really old then its not the battery wires its the batteries themselves.
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Old Jul 10, 2012, 12:04 PM
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jcdfrd:
Castle recommended 2 cap packs per fan. I installed one pack between the ESC and the end of the standard wires that come out of the ESC (these are the ones going to the battery). I then installed the second pack immediately after the connectors that go on the battery cables. This setup seems to work well with the fans as my ripple voltages were very good. In fact the ripple voltages were significantly lower than the same setup on my Falcon 120 (battery wires on the Falcon were about 12"). In fact I think that the cap packs seem to work well on the A-10 so I am going to put one cap pack in the Falcon 120. While the ripple voltage on the Falcon was not bad, I think I can make it better.

I have included a couple of photos that might better convery how I set things up. the first photo is of the cap pack installed on the ESC cables.The second photo is of the cap pack I soldered to the battery cable leads. If you look carefully (sorry for the poor photo quality) just above (towards the top of the photo) the battery cable cap packs you will see the cap packs soldered to the ESC cables. Hope this explanation helps.

Ed
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