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-   -   Everything You Wanted To Know About Electric Powered Flight (https://www.wattflyer.com/forums/showthread.php?t=31071)

Nemesiselite 06-12-2008 07:22 PM

Originally Posted by Pappy (Post 423328)
what is the max voltage you can put on a futaba 6 chanel reciver with out burning it up? Will it handle 7.4 lipo?My 6 volt flight batterys have bit the dust and about coust me a airplane Glenn

futaba 6 channel receiver - Power Requirements: 4.8 to 6.0V (shared with servos)

if u want to use a 7.4 lipo, get a bec.

I use a Align 6A External BEC, which shows the power of the lipo.
And there are meny bec's u can use.


Pappy 06-12-2008 09:03 PM

Thanks a lot thats what i needed to know..tThat's what WattFlyer is all about


AEAJR 06-13-2008 10:47 AM


even if your receiver could handle the 8.4V of the lipo, the servos likely can not. Some of the newer receivers can handle higher voltages, but they pass that voltage to the servos which can result in loss of the magic smoke. :(

Pappy 06-14-2008 04:03 AM

Don't need no smoke. Thanks


DaxFX 06-17-2008 10:03 AM

a little help here again. I have the complete gide several times I have learn lots of thing. I am trying to figure out what prop to use and mi brain just go on vacation. I have the GWS corsair with the eps400-D 3:00.1 and a 9.6v pack. I have 3 diferent props APC 9x7.5 sf GWS 9x7 3 blades and GWS 10x6 I read on a chart from GWS that for that setup the best one will be GWS 9x7 that will gave me 93 watts but instead I just ordered the 9x7.5 and 9x7 GWS but 3 blades ( I like the look) I hink i do wrong with those props the 3 blade will be fine on my SuperCub 480 9.6v but the 9x7.5 will be good for the 400-d 3.1 ? is have only half an inch more in pitch than recomended how that .5" will affect did I will get more power (wats). I will be able to use the 9x7x3 on the 400-D .... more speed and less thrust ? can any one help me here. speed controller is 15amp. if the recomended for my motor is 9x7 aht diference will cause putting a 9x7x3

how can I messure myself the watts with my props ?

AEAJR 06-17-2008 10:47 AM

Originally Posted by DaxFX (Post 426226)

how can I messure myself the watts with my props ?

You need a wattmeter. Here ae some examples.


I have this one - Watts-up the description below is taken from Tower Hobbies site.

This is the RC Electronics Watts Up Watt Meter with Blue Case.

Measures eight essential electrical values;

Captures Peak Amps, Peak Watts and Minimum Volts events as short as
a fraction of a second

Current: 0-100A Peak, 50A Continuous, .01A Resolution
Charge: 0-65535mAh, 1mAh resolution
Power: 0-6500 Watts, .1W Resolution
Voltage: 4-60V, .01 Resolution (0V min. using auxiliary
receiver battery

Energy: 0-6500 Watt Hours, .1Wh resolution
Powered by circuit-no battery to change
16 character, 2 row LCD display

INCLUDES: RC Electronics Watts Up Watt Meter, four 3.8" (96mm) length 14 gauge
stranded silicone source and load wires without connectors,

REQUIRES: Connectors depending on type of battery

DaxFX 06-17-2008 10:58 AM

WOW if my brain was in vacation !! now leaves me forever !! jajaja !! thanks for the links is something i need ..

Pappy 06-17-2008 01:27 PM

Fixd my problum with lipo chang ofer got a voltage regulator from Radio South.Thanks a lot you all


mred 06-17-2008 04:52 PM

You are still going to need a watt meter for all the times you have questions about something going one with your system. A watt meter is part of the necessary things you need to run electric power. Without it, you are running in the dark. It is sort of one of those MUST have items that everyone needs and not everyone gets. Some of them are letting the blue smoke out and wondering why, when it could have been avoided with a simple watt meter.
No matter what you get for tools, this is one you can't really live without, unless you like letting the smoke out and it is REALLY hard to put it back in again.

oscarpescador 06-27-2008 07:22 PM

speed control
my MYSTERY 60 A speed control work with 3 cell battery only. I need to make something (reprogram), or ????? for 4 cell battery? .The motor make a short yogs

mred 06-28-2008 12:38 AM

You will have to e-mail whoever you bought it from to get the program information unless someone here has it. I have the 40A and I can program it for 4 cells, but I do not know about the 60A ESC.

oscarpescador 06-28-2008 11:28 PM

speed controller mystery 60 A
Thanks Ed .I bougth it in Ebay,I think that the chinese guy who sold it to me didn't know anything about how it works:mad:

DaxFX 06-29-2008 01:29 AM

Originally Posted by oscarpescador (Post 432807)
my MYSTERY 60 A speed control work with 3 cell battery only. I need to make something (reprogram), or ????? for 4 cell battery? .The motor make a short yogs

take a look here

mred 06-29-2008 01:42 AM

There you go. Now you have to manual for it. I bought mine on E-Bay also and sent an E-Mail to the guy I bought it from and ask him for a manual. He sent it to me by return E-Mail and I have been using that. I never got anything with it. One thing I learned for buying from these guys. Most of the time you never get a manual. Take care.

AEAJR 08-28-2008 04:21 PM


Manufacturers use different wire winds to produce different Kv results.

Kv is a number that relates to how many RPMs a given motor will spin based
on applied voltage. You will see specs on motors where it says Kv=860.
That means that the motor will spin at 860 rpms if you apply one volt to it.
If you apply 7 volts it will span at 6020 rpms.

If the manufacturer takes the same motor he can wind it so that it will
have a lower Kv rating, which typically produces more torque, so these are
typically used with large propellers that will be turned slower. These are
very popular on gliders, for example, where climb angle and climb rate is
much more important than top speed.

Take the same motor and wind it differently and it will have a higher Kv
rating producing higher speeds for a given voltage. These are typically
used with smaller props for higher top speeds. Or they can be used with gear
boxes to handle those big props, providing a similar result to low KV
motors. Sometimes a gear box works better in the installation.

You would also take KV into consideration based on what battery you plan to

If you look here you will see that a given motor is offered in several Kv
ratings. They make suggestions as to which motor is best matched with which
prop and which battery packs. If you click on a given motor you can see what
kinds of power is drawn based on which pack and which prop. If you click on
each of the motors within a model you can see the very different power
curves produced by the different battery/prop combos. Here you see the same
motor with a different wind producing a different Kv result, each optimized
for a different purpose.

So, how does this add to other information about motors?

I first set a watts/pound target for my plane depending on the performance I
want. I typically target between 70 and 100 watts per pound for sport
planes and gliders. I don't fly 3D.

Then I consider whether I am looking for high speed or high climb rate. A
glider or a 3D plane would be optimized more toward the climb rate side of
this discussion. A pylon racer would be optimized more for speed. A
plane might be somewhere in the middle.

Now I get down to prop and battery. Wider prop for better climb, narrower
deeper prop for higher speed. Now look at the motor character based on
either battery target or prop target and choose the motor/battery/prop combo
that meets your objectives.

That is kind of high level but you get the idea.

Arkitexas 10-12-2008 12:42 AM


I wrote a short essay on antennas you might consider.
post #14


AEAJR 10-12-2008 03:54 AM

Good article Rick. Thanks for posting the link.

mred 10-12-2008 02:55 PM

Originally Posted by Arkitexas (Post 488774)
I wrote a short essay on antennas you might consider.
post #14


I read your essay on antennas and overall, it was very interesting. The one thing I didn't see you mention was anything about reflection. Any object, especially metal, will reflect the signal from the transmitter and if picked up by the receiver, can cause the receiver to try and read both signals at the same time. This can cause the signal strength to be reduced and in some cases cancel each other out. Now a reduced signal strength won't normally hurt the reception and the receiver will keep working and while the receiver is seeing an effective loss of the signal, it is still strong enough for the plane to keep flying and you may never notice the loss in signal strength. However, if the signal bouncing off an object happens to reach the receiver at 180 degrees to the transmitted signal, they will cancel each other out. This effect can cause the receiver to totally loose the signal and "go nuts" to the point of either doing something really unexpected, or can lead to a total loss of control and a resounding crash.

I used to fly at an AFB on the flight line and we had one area that was dangerous to stand because of the reflection off the hangers. They still fly there today and in fact hold a big race meet there every year. The race is held out on the runway however and the problem with reflection is not encountered there, but get a little closer to the hangers and you are going down.

The same thing can happen at other flying fields if there is some sort of building that happens to be in the right spot. If it is a wooden building there is no problem, but if that building happens to be a metal shed like I have seen on a couple of flying fields, you may just encounter this effect. If your airplanes are doing something unexpected in the same area of the field, you are probably getting some reflection and should avoid this area. Normally just moving over a few feet puts the reflection into an area that no one is effected by and you can continue to fly with no problems.


Arkitexas 10-13-2008 11:33 PM


I agree, reflection is a very pertinent subject and will look at adding it to the essay. The difficulty is in describing how to find buildings and surfaces to beware of. Sometimes the only way to find those spots is from listening to all the flyers who have been shot down by the interference. Like your AFB example, you can fly there, just not at that end of the flight line.


mred 10-13-2008 11:59 PM

Really it wasn't that big of an area. I never did find the exact cause of the reflections, but the area has hangars all the way down the flight line. There was only one small area we had to avoid and that was about 50 feet long. We finally drew a line in that area and marked it keep out. From then on we had no problems with it.

Before that, we had several crashes that caused a lot of people to scratch their heads a lot. Trying to figure that one out took a little time, but we finally started seeing problems with anyone standing in that one area and not all planes bit the dust. Some were fast enough that they got through it before they hit the ground and we regained control again. We started doing a few fly-bys in that area moving around a little to see what would happen. We found that as the reflections moved, we could safely fly through that area, but move over a few feet and the plane went nuts again.

Reflections are a strange thing. They can be caused by a simple small shed, or a big hanger, but the size of the building is not always what determines where or how big the area will be.


AEAJR 10-14-2008 11:15 AM


I suggest you take any further discussion about antennas into the tread on antennas. A post or two here is fine but I don't want to turn this into a discussion on antennas.


sleddog 10-27-2008 02:34 AM



Another great article with great timing for this new flier...Thanks


AEAJR 10-27-2008 04:45 AM


Originally Posted by AEAJR (Post 464791)


Another great article with great timing for this new flier...Thanks


We do it all for you. ;)

f4you 11-16-2008 02:24 AM

Can I put two brushless motors on one ESC (assuming the ESC is rated high enough to handle the loads)?

OOps, never mind, dug deeper and got my answer. Castle crrations' site has an article discussing the question.

Larry3215 11-16-2008 03:00 AM

Originally Posted by f4you (Post 505967)
Can I put two brushless motors on one ESC (assuming the ESC is rated high enough to handle the loads)?

OOps, never mind, dug deeper and got my answer. Castle crrations' site has an article discussing the question.

In rare cases it works, but generally speaking - no :)

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