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Old Mar 29, 2012, 01:17 AM
Mark Harrison
USA, CA, Piedmont
Joined Jun 2010
2,174 Posts
Quote:
Originally Posted by AmishLou View Post
How do you test how much voltage per cell is left in a battery after a flight? What are some recommendations for a good piece of equipment to do this?
Here's a nifty one that shows all the cells at once with a nice OLED display.
Not bad for $11.

http://eastbay-rc.blogspot.com/2012/...ed-screen.html
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Old Mar 29, 2012, 01:53 AM
Argue for your limitations
ajbaker's Avatar
Lincoln, CA
Joined Oct 2006
8,421 Posts
Timing

Quote:
Originally Posted by CPMBOY View Post
sorry for asking this maybe-already-been-asked question. What is the ESC setting for the Bixler with stock motor, 2200 mah batt. Im using EMAX 40a ESC with programming card....the settings are:
Ok..the settings are:
1. brake type: Off/soft/hard
2. timming mode: low/mid/hi
3. cut off mode: soft cut/cut off
4. start mode: fast/soft/very soft
5. gov mode: OFF/gov-low/gov-hi
6. Li-XX cells: auto/2 cells/3cells/XX cells
7. cut off voltage: low/mid/hi
Quote:
Originally Posted by CPMBOY View Post
stock motor
Ok. Got it. A stock motor could be brushed or brushless, though. But, your EMAX ESC confirms that you have a brushless (9-pole motor).
Given that conclusion. Here are my suggestions:
1. Off. Although, both settings are "right"
2. High. *see note later
3. Soft cutoff.
4. Fast (always - the others are used for helicopters)
5. Off
6. Auto
7. High
*Here is how most ESC programming instructions read-
Timing Low/Medium/High:
In normal cases, low timing can be used for most motors, But for high efficiency, we recommend the Low timing for 2 pole motors and medim timing for 6 pole motors and above. For higher, High timing can be chosen.

Having quoted that, I use High timing for ALL outrunner motors. The reason for this is to gain better performance (at the cost of some flying time). That is just my opinion.
FWIW, you ask 10 modelers about how they set the above 7 settings and you will get 10 different answers. I have purposely not given any reasons for the other 6 settings because it would definitely launch an OT discussion that I doubt would benefit many folks. If you want more in depth information, you might want to search RCG for ESC programming.

AJ
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Old Mar 29, 2012, 02:04 AM
Argue for your limitations
ajbaker's Avatar
Lincoln, CA
Joined Oct 2006
8,421 Posts
Quote:
Originally Posted by taz101 View Post
Forgive my ignorance but wouldn't setting the brake to hard slow it down MORE. Wouldn't it be like throwing out an anker instead of just turning off the motor. If you set the brake to soft the prop will slow down to a stop, instead of the prop stopping straight away like an air brake or air spoiler!!

LURCH
You are correct.
AJ
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Old Mar 29, 2012, 02:13 AM
Argue for your limitations
ajbaker's Avatar
Lincoln, CA
Joined Oct 2006
8,421 Posts
soft or hard brake

Quote:
Originally Posted by Dkumagai View Post
Just a quick question on the brake function. I assumed that brakes lock the bell in place by pumping a constant low current into the stator coils rather than sequencing them to induce rotation. If that's the case, does having brakes on draw a significant amount of current? I also wonder how much drag a prop generates spinning around in the wind. When I'm gliding the prop almost never stops moving even at low speed and it takes a fair amount of force to advance the bell on my motor. Haha guess that answers my question.
So, what is your answer? I am not clear on what your conclusion is. It is generally accepted that a free wheeling prop induces more drag than one that is stopped. Yes. It does require more current to hold the prop stopped although I have never measured it. My assumption is that a stopped prop would use slightly more current while stopped in the air than when it is on a motor that is mounted to the bench. Again, I have not tested that theory. In any case, I doubt that we are talking about a great deal of battery life involved. Like many other things, it is a matter of preference. For me, I prefer the brake function to be active.
AJ
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Old Mar 29, 2012, 02:30 AM
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Joined Mar 2012
12 Posts
Hello Guys! I was able to fly my plane. But after 4 times of taking off and landing. On the 4th flight the wings went off. Should I put glue on the wings? I deciding whether to put some packing tape on it for the meantime. There's a small damage on my wing prolly around 3/4 inch on the back part of it. I just put some tape on it.

It seems that flying the real thing is harder compare to simulator I need to practice more. I dont feel so comfortable flying this SS.
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Old Mar 29, 2012, 03:03 AM
Registered User
United States, WA, Seattle
Joined Oct 2011
286 Posts
Quote:
Originally Posted by ajbaker View Post
So, what is your answer? I am not clear on what your conclusion is. It is generally accepted that a free wheeling prop induces more drag than one that is stopped. Yes. It does require more current to hold the prop stopped although I have never measured it. My assumption is that a stopped prop would use slightly more current while stopped in the air than when it is on a motor that is mounted to the bench. Again, I have not tested that theory. In any case, I doubt that we are talking about a great deal of battery life involved. Like many other things, it is a matter of preference. For me, I prefer the brake function to be active.
AJ
My conclusion was that given the amount of force that is required to turn the propeller and given the fact that it whizzes pretty fast when merely gliding means that it's catching a lot of wind. It just made me realize that the spinning prop was a visualization of the drag doing work in a sense.

However, I'm having a hard time seeing why a free spinning prop induces significantly more drag that a stationary one. If I were to guess why this is is that a moving prop might make contact with more air molecules than a stationary one given a constant airspeed. Kind of like how it's said that you get wetter by running in the rain than walking.

In any case I'll give brakes a try and see how that affects my gliding.
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Old Mar 29, 2012, 03:13 AM
Registered User
United States, WA, Seattle
Joined Oct 2011
286 Posts
Quote:
Originally Posted by zaai View Post
Hello Guys! I was able to fly my plane. But after 4 times of taking off and landing. On the 4th flight the wings went off. Should I put glue on the wings? I deciding whether to put some packing tape on it for the meantime. There's a small damage on my wing prolly around 3/4 inch on the back part of it. I just put some tape on it.

It seems that flying the real thing is harder compare to simulator I need to practice more. I dont feel so comfortable flying this SS.
I highly recommend you do not glue your wings on. First, the plane is almost 5 feet in wingspan so that would make it very cumbersome to transport or store. Also, it's simply not necessary. Some sort of restraint is needed, but not a whole lot. I use high strength neodymium magnets. I feel that a nonpermanent wing retention solution would allow for more give in a crash and make them less likely to break. And in the event that you needed to replace a wing, it would be a lot easier if you didn't glue them in.
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Old Mar 29, 2012, 09:16 AM
Row 0, Seat A
G550Ted's Avatar
Savannah, GA
Joined Jan 2008
2,705 Posts
Quote:
Originally Posted by Dkumagai View Post
My conclusion was that given the amount of force that is required to turn the propeller and given the fact that it whizzes pretty fast when merely gliding means that it's catching a lot of wind. It just made me realize that the spinning prop was a visualization of the drag doing work in a sense.

However, I'm having a hard time seeing why a free spinning prop induces significantly more drag that a stationary one. If I were to guess why this is is that a moving prop might make contact with more air molecules than a stationary one given a constant airspeed. Kind of like how it's said that you get wetter by running in the rain than walking.

In any case I'll give brakes a try and see how that affects my gliding.
Your assumption and analogy aren't quite correct but the bottom line is that a windmilling prop creates more drag than one which is stopped. For a somewhat better glide you should set the ESC to Brake - ON. How much current any given motor uses to accomplish the brake function can only be determined by using a watt meter.

Ted
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Old Mar 29, 2012, 09:42 AM
Registered User
jeeper1977's Avatar
Lake Havasu City AZ
Joined Feb 2009
165 Posts
Quote:
Originally Posted by ajbaker View Post
Ok. Got it. A stock motor could be brushed or brushless, though. But, your EMAX ESC confirms that you have a brushless (9-pole motor).
Given that conclusion. Here are my suggestions:
1. Off. Although, both settings are "right"
2. High. *see note later
3. Soft cutoff.
4. Fast (always - the others are used for helicopters)
5. Off
6. Auto
7. High
*Here is how most ESC programming instructions read-
Timing Low/Medium/High:
In normal cases, low timing can be used for most motors, But for high efficiency, we recommend the Low timing for 2 pole motors and medim timing for 6 pole motors and above. For higher, High timing can be chosen.

Having quoted that, I use High timing for ALL outrunner motors. The reason for this is to gain better performance (at the cost of some flying time). That is just my opinion.
FWIW, you ask 10 modelers about how they set the above 7 settings and you will get 10 different answers. I have purposely not given any reasons for the other 6 settings because it would definitely launch an OT discussion that I doubt would benefit many folks. If you want more in depth information, you might want to search RCG for ESC programming.

AJ
How about function #8 on some ESC's, what music to play
And yes I have that turned off on my ESC's.
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Old Mar 29, 2012, 10:08 AM
Registered User
United States, WA, Seattle
Joined Oct 2011
286 Posts
Quote:
Originally Posted by G550Ted View Post
Your assumption and analogy aren't quite correct but the bottom line is that a windmilling prop creates more drag than one which is stopped. For a somewhat better glide you should set the ESC to Brake - ON. How much current any given motor uses to accomplish the brake function can only be determined by using a watt meter.

Ted
Haha, well maybe that's why I'm a software and not aerospace engineer. I only touched on principles like drag in my year of calc physics. I would like to hear your explanation though.
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Old Mar 29, 2012, 10:57 AM
Suspended Account
Joined Feb 2012
123 Posts
Quote:
Originally Posted by taz101 View Post
Forgive my ignorance but wouldn't setting the brake to hard slow it down MORE. Wouldn't it be like throwing out an anker instead of just turning off the motor. If you set the brake to soft the prop will slow down to a stop, instead of the prop stopping straight away like an air brake or air spoiler!!

LURCH
It seems counter intuitive but the propeller creates less drag if it is stopped so the quicker it stops the faster drag goes down. Letting the prop continue to windmill creates secondary drag from friction, it takes energy to spin the prop and the plane slows down.
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Old Mar 29, 2012, 11:01 AM
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Eagle202's Avatar
United States, FL, Clearwater
Joined Aug 2011
1,595 Posts
Quote:
Originally Posted by zaai View Post
Hello Guys! I was able to fly my plane. But after 4 times of taking off and landing. On the 4th flight the wings went off. Should I put glue on the wings? I deciding whether to put some packing tape on it for the meantime. There's a small damage on my wing prolly around 3/4 inch on the back part of it. I just put some tape on it.

It seems that flying the real thing is harder compare to simulator I need to practice more. I dont feel so comfortable flying this SS.
zaai

Don't glue your wings. Check out page 1 of this thread. AJ has put together a number of ways to hold the wings in place so they won't fall off the fuse. There is even a modification for the elevator wing that allows removal yet is strong when attached.

Read the notes. Ask questions. Try out your plane. Above all have fun.

Vince
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Old Mar 29, 2012, 11:30 AM
Registered User
United States, OH, Dayton
Joined Feb 2012
34 Posts
SkyS PNP fuselage

Sorry if this is an already beaten, dead horse but I did do a quick cursory search!

I recently bought a SkyS PNP brushless and it has arrived in great condition. However I've come to the realization that I'll be adding a boatload of components for FPV. The problem with the PNP is that the fuselage is already glued together and I'm not sure if I can get to all of that real estate through the canopy hole.

Should I try to cut the fuselage in half, cut a little access panel, or exchange it for the SkyS kit?

I appreciate any advice!!!
Brian
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Old Mar 29, 2012, 11:35 AM
Limited flyer
Limited flyer's Avatar
Joined Dec 2011
412 Posts
Don't you mean to sayAJ has put togeather many different wing attatchment meathods from many different flyers. Tthe way you say it would suggest he thought of them all.
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Old Mar 29, 2012, 11:46 AM
Suspended Account
Joined Feb 2012
123 Posts
Quote:
Originally Posted by bgarber View Post
Sorry if this is an already beaten, dead horse but I did do a quick cursory search!

I recently bought a SkyS PNP brushless and it has arrived in great condition. However I've come to the realization that I'll be adding a boatload of components for FPV. The problem with the PNP is that the fuselage is already glued together and I'm not sure if I can get to all of that real estate through the canopy hole.

Should I try to cut the fuselage in half, cut a little access panel, or exchange it for the SkyS kit?

I appreciate any advice!!!
Brian
You can cut an access panel in the bottom or the sides and then glue them back with CA once you have put all of your components in place. If you use a sharp Exacto knife and are careful it will not be very noticeable. Most FPV planes require some modification.
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