ufale
Flying officer
Posts: 2
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Post by ufale on Sept 27, 2010 10:19:15 GMT 1
I have a spektrum 6dxi,and I would like to upgrade my supercub lp's radio system. What servos, receiver, and esc are good for this goal. I am not afraid to spend a few bucks, but I would like to keep it under the cost of a new Supercub. Thanks.
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Post by iflyforfun on Sept 27, 2010 12:13:13 GMT 1
I have a spektrum 6dxi,and I would like to upgrade my supercub lp's radio system. What servos, receiver, and esc are good for this goal. I am not afraid to spend a few bucks, but I would like to keep it under the cost of a new Supercub. Thanks. DX6i was a great Choice for a TX. I also have One And Love it!! I use the AR6110e Receiver and am very happy with it. It is tiny and weighs only 3.9 grams. Using the range test feature on the DX6i it works perfectly. I fly at a old closed airport in New Jersey with a 1900 foot runway. Last time I was flying I had my brother hold the plane over his head and I drove to the other end of the runway and still had full control of the plane. ( I could not see the dam thing, just my brother holding something over his head). Fantastic range. Only $50 dollars!!!! www.horizonhobby.com/Products/Default.aspx?ProdID=SPMAR6110EI kept the original servos in my SC and they work fine. When I added ailerons and flaps I used the HXT900 from Hobby King. They seem to be the choice for many flyers and I have not had any problems with them. hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=662&Product_Name=HXT900_9g_/_1.6kg_/_.12sec_Micro_ServoThe HXT servos have been out of stock for weeks now and I would not wait for them. This is another choice. www.headsuprc.com/servlet/the-1410/SERVO--dsh---9g/DetailI have these servos for another build that I am doing and have never flown with them but I was told that they are great servos and work just fine. If you read about them you will see that HURC recommends them for the SC. They have $2:00 shipping and you'll have them in 3 days. Ifly |
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Post by iflyforfun on Sept 27, 2010 12:20:31 GMT 1
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Post by chinaclipper on Oct 20, 2010 17:51:03 GMT 1
I am going to also upgrade. I am using the HXT900 for ALL four servos, ie rudder, elevator and ailerons (2).
Will the HXT900 be OK (have enough torque at 1.6kg/cm) for the rudder and elevator servos?
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Post by flydiver on Oct 21, 2010 1:04:45 GMT 1
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Post by killioughtta on Oct 21, 2010 10:37:38 GMT 1
lol. That thread should be under some kind of "Extra Sticky" mode. It gets passed around here more than any other. It seems to find its way into the semi-weekly "Brushless Upgrade Help" threads. Seriously, ufale, you need to read it; SLOWLY. Take your time to understand it and read the discussion. If you have further questions, ask here and we shall deliver. |
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Post by leisureshoot on Oct 21, 2010 14:53:29 GMT 1
Doing some searches for "Current Draw Amp Standard Servo" I found some claims of .250-.500 by people posting on forums for park flyer sized standard servos. Is this number a pipe dream? Has anyone here measured servo currents? If under .500 mA is reasonable, that is a much better scenario for our use.
I have Parkzone SV80's in my SC and will try to measure the current on them tonight.
I just ordered a standard 43 oz stall @ 4.8v servo from HeadsUpRC, and I'll also test it for reference while installing it in my other plane.
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Post by flydiver on Oct 21, 2010 17:00:33 GMT 1
You saw that link in the above link I posted for servo draw? I've seen very little definitive data on servo draw at all. Most folks don't have the tools.
A wattmeter is not a sufficient tool for getting this info as it averages over too long a time frame. If that was being used the data is not terribly useful and the person gathering it doesn't know what they are doing.
If you find some other decent sources (links please), I'd sure like to know.
Luckily it lists the HS-55 and the HXT900, and several other favorite servo choices.
ufale - The HeadsUPRC link is full of great info. Jeff is a wonderful guy....but-don't bother with the TowerPro Motors and Mag8 ESC. They are bottom of the bucket stuff. Look at the EMAX ESC (hobbywing) and his 'better' motors as reasonable options.
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Post by chinaclipper on Oct 21, 2010 17:57:22 GMT 1
So I read all I can about the BEC and HXT900 servo problem (Low amps, servo dies, plane follows!) Got it, will remedy. Stupid question alert!!!  : Do I use a different battery, then, ie, one for the BEC and one for the ESC for the motor? I looked, and this was not made clear to me.... |
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Post by flydiver on Oct 21, 2010 18:28:53 GMT 1
Using a separate receiver battery is one of the options but not necessary for this application.
I used to wonder what the RX battery (those little 4-5 cell NiXX jobs) were for.
Think about nitro planes. They don't have a motor battery but they do have servos and an RX. You plug the RX battery into the [battery slot] in the RX and > power!
Or think about unpowered gliders and slope planes-same thing. Electronics get power from the RX battery.
What we think of as a conventional ESC is really 2 devices: an ESC + BEC
The [battery eliminator circuit] was invented when someone thought, 'Hey, I have a battery. What if I step the voltage down and power my electronics with that?" Brilliant. It works but it has some flaws = can't handle high current and is often too small for more complex applications.
So, you disable the on-board BEC (pull the red wire) and add a superior aftermarket one that can handle the job better. It still gets it's power from the main battery.
SERV0 POWER ALERT! HK is selling some Turnigy 9gm servos for even cheaper than the HXT900. They draw almost 2x the power the HXT's do. They are not a good buy.
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Post by chinaclipper on Oct 21, 2010 22:28:39 GMT 1
Thanks Flydriver. I think i get it now.
The aftermarket BEC will connect to the usual flight battery, but will replace the "stock" BEC on-board the ESC with a much better one.
Now, off to the hobby store!
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Post by leisureshoot on Oct 21, 2010 23:49:21 GMT 1
You saw that link in the above link I posted for servo draw? I've seen very little definitive data on servo draw at all. Most folks don't have the tools. A wattmeter is not a sufficient tool for getting this info as it averages over too long a time frame. If that was being used the data is not terribly useful and the person gathering it doesn't know what they are doing. What about a multimeter, amp setting? |
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Post by flydiver on Oct 22, 2010 6:54:54 GMT 1
Note as far as I know unless you have something special.
An oscilloscope or special servo measuring mechanisms. Take a look at the oscilloscope graph in the link.
I was maybe a tad harsh in the last statement. Using a wattmeter is not entirely useless for servo testing. For motor testing it is almost essential. If you have a stuck or binding servo it can short the motor and make a prolonged amp draw spike which can be quite useful to see and very good to find. A binding servo is very bad.
Rapidly cycling ALL the servos to full travel very rapidly for a couple minutes, no motor running, fully charged battery stresses the BEC fully and you may see the ESC/BEC heat up or the servos begin to bog down as the BEC becomes stressed. You can also get an average of all the servos working full tilt. If the servos do start to fail you know you could be in trouble flying that setup.
What you can't see is the peak draw on a wattmeter.
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Post by leisureshoot on Oct 22, 2010 14:55:13 GMT 1
I kept the original servos in my SC and they work fine. When I added ailerons and flaps I used the HXT900 from Hobby King. They seem to be the choice for many flyers and I have not had any problems with them. Ifly Did your SC have the 5-wire servos? How did you keep those? |
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Post by leisureshoot on Oct 22, 2010 14:57:43 GMT 1
You saw that link in the above link I posted for servo draw? I've seen very little definitive data on servo draw at all. Most folks don't have the tools. If you find some other decent sources (links please), I'd sure like to know. No definitive data. I only saw anecdotal comments on rcuniverse or rcgroups threads, which is why I was asking if those numbers are reasonable, or overly optimistic. |
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