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Old Nov 23, 2010, 06:52 PM
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Canton, Michigan USA
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Originally Posted by ajbaker View Post
The Lipo - Buying a smaller 4-cell LiPo is not going to change anything except the weight. Of course, it would have to be at least a 800mah 20C LiPo to handle the 14.3A max current. Anything smaller would probably trash the LiPo.

The motor - Well, yes, that motor is a screamer, too. And, it is designed to run on a 3S at 25-30A. Then, you would need a 1500mah 3S1P 20C LiPo at a minimum to handle the increased amp draw.

Prof100 made some great suggestions that I agree with, too.

BTW-You can use a 4S on either of the above motors. The game is to not pull more than the max rated amps of the motor.

In Short, There are many "right" answers to your situation. The fun part of this hobby is finding the "perfect" combination that meets your flying needs. Naturally, part of that is staying out of trouble with Ohms law. Officer Ohm won't give you a ticket, he will burn up some/all of your components or laugh at you for carrying a lot of weight that you don't need. But, I know you have the most important tool that IMO is mandatory for power system mods -> A WattMeter. So, carry on. It looks like you are having a good time and I don't see any red flags (yet). Just my .02 worth.


Hmmmmmm.... Let me toss this one at Prof100-> Of course, in the above, if he wanted to stay with a 4S for the 2836-2200, he would still have to use the math and utilize a 4S 1500mah 20C (given that the motor is 30A max) since the amps are the same in a series arrangement.
Well, it seems we could use a 2S 1500mah 20C and re prop to get the 30A max. Then, we could save the weight. I know, of course, the flight times would be shorter but the LiPo load would be lighter thereby offsetting (a little bit) the flight time loss. I haven't played with the above theory except as required by various airplanes (like the 1-cell Vapor). In summary, it seems like it would be wiser to use a 2S LiPo in most of my planes (that have a 2s-3s rated motor) because of the lighter weight. This is not a loaded question. I have not done any solid research to support my ramblings above. So, what are your thoughts?

AJ

P.S. For those of you reading this, I strongly suggest that you purchase the Watt Meter shown above (or one just like it - the WattsUp) if you plan on experimenting in any way with the power system. IMO, that was a significant contribution to road_rascal's great success (of course, his superior flying skills are a given).
AJ,

I like saving the weight. I think it would work but I am not seeing a "normal" prop that would you could get it up to 30 amps.

On a side note I would like to try a 2800 KV Microdan outrunner. It's powerful and very light.

Bill
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Old Nov 23, 2010, 06:55 PM
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Lincoln, CA
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Originally Posted by moon12 View Post
I just watched and enjoyed Mike m2's video....sounds like he's ready to upgrade to brushless. I'm in no position to make recommendations, but If I was bored with my brushed Sky Surfer on 7.4v, and I had my new brushless motor ordered I'd probably try a 3cell lipo in that baby
What do you experts say, would doing that jeopardize his plane? would the ESC handle it?
harry
I think I sort of addressed that about 4 posts ago. But, to give you a direct IMO only answer - No, I don't think so. He is quite knowledgeable (again, IMO) about the limits of power systems and how to deal with them. Yes, the ESC would handle it (he might have to use a smaller prop, though if he goes to 3S). The whole game (of power systems) can be summed up in one statement -> Do NOT exceed the max rated amps of whatever motor (and ESC) you are using. There again, is a reason to have a Watt Meter in your tool box.
AJ
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Last edited by ajbaker; Nov 23, 2010 at 07:12 PM. Reason: clarify statement
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Old Nov 23, 2010, 06:57 PM
Argue for your limitations
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Lincoln, CA
Joined Oct 2006
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MicroDan products

Quote:
Originally Posted by Prof100 View Post
AJ,

I like saving the weight. I think it would work but I am not seeing a "normal" prop that would you could get it up to 30 amps.

On a side note I would like to try a 2800 KV Microdan outrunner. It's powerful and very light.

Bill
Golly, it is scary how we both think alike. I have been flirting with that motor for some time now. He certainly builds the "Rolls Royce" motors IMO. I have heard nothing but positive things about him and his motors. Maybe, that would be the ideal motor to do some research go support my thoughts. Check out the specs on that motor. They suggest that maybe my thoughts are OK about the 2S and Re-Prop.
I think we both have been around the block enough times to know that a smaller Kv with a larger prop is a more efficient power system.
AJ
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Old Nov 23, 2010, 06:58 PM
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Canton, Michigan USA
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Quote:
Originally Posted by ajbaker View Post
I think I sort of addressed that about 4 posts ago. But, to give you a direct IMO only answer - No, I don't think so. He is quite knowledgeable (again, IMO) about the limits of power systems and how to deal with them. Yes, the ESC would handle it (he might have to use a smaller prop, though if he goes to 3S). The whole game can be summed up in one statement -> Do NOT exceed the max rated amps of whatever motor you are using. There again, is a reason to have a Watt Meter in your tool box.
AJ
AJ,

Agreed. For example, you can burst a 2212-06 Suppo on a 6x4 but not sustained. If you insist on flying WOT all the time the magnets with cook. Same for a 2409-12T TP. Prop it with 8x6 and run sustained WOT and you WILL discolor the wiring.

Bill
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Old Nov 23, 2010, 07:01 PM
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West Texas USA
Joined Mar 2008
662 Posts
[QUOTE=moon12;16631446]
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Originally Posted by garymcc View Post
Flew the SkyS v2 twice, once with a 3S 1500mah and once with a 3S 2200mah.
The wind was 10-12mph gusting. The plane flew about like my Clouds Fly.
CG was approximately middle of spar cover.

The stock motor seems to have adequate power with the 6x4E prop for decent climb outs. Also, the motor seems to be very smooth, no rattle noises.

garymcc....where's the vids of your maiden?
You know what Aj says....
I'd love to see where your flying, I'm freezing up here in Ontario
harry
Sorry, I didn't take the FlyCam. I was in a hurry to fly before it got dark.
Besides, there are plenty of boring videos to watch on the web, mine would just add to the count. Yes, I know what AJ says. I'll do better next time, I promise.

I'm in west Texas, USA. The high today was 79F or so. I don't envy you this time of year. The summer is a different story - Canada, what I've seen of it, is beautiful.
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Old Nov 23, 2010, 07:08 PM
Crashasaurus Dumbthumus
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USA, MN, Apple Valley
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I went ahead and ordered two 4s2200mAh lipos from Hobbypartz. I ran the setup again, this time with an APC 6x5.5e and got close to the same watts and amps using the 6x4x3 prop. Pitch speed is probably higher and the APC prop is just a bit noisier. I'm guessing 28oz AUW with this Sky Surfer. I should probably weigh my other one. AJ, what makes you think I have superior flying skills ?
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Old Nov 23, 2010, 08:05 PM
Why so serious?
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United States, FL, Cape Coral
Joined Dec 2007
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Quote:
Originally Posted by road_rascal View Post
I went ahead and ordered two 4s2200mAh lipos from Hobbypartz. I ran the setup again, this time with an APC 6x5.5e and got close to the same watts and amps using the 6x4x3 prop. Pitch speed is probably higher and the APC prop is just a bit noisier. I'm guessing 28oz AUW with this Sky Surfer. I should probably weigh my other one. AJ, what makes you think I have superior flying skills ?
With all the things you have done and the results you listed, there is only one explanation.
The motor has the wrong sticker on it. It's probably around 11-1200kv.
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Old Nov 23, 2010, 08:34 PM
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San Diego, Ca.
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Painting Sky Surfer

What is a safe way of Painting Sky Surfer?
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Old Nov 23, 2010, 08:37 PM
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Lincoln, CA
Joined Oct 2006
8,422 Posts
Flying abilities

Quote:
Originally Posted by road_rascal View Post
I went ahead and ordered two 4s2200mAh lipos from Hobbypartz. I ran the setup again, this time with an APC 6x5.5e and got close to the same watts and amps using the 6x4x3 prop. Pitch speed is probably higher and the APC prop is just a bit noisier. I'm guessing 28oz AUW with this Sky Surfer. I should probably weigh my other one. AJ, what makes you think I have superior flying skills ?
Your posts and articulation of RC flying. If you said you were brand new at RC flying, I would not believe you. Can you please measure the Kv of the motors that you intend to use? I am curious about the most recent two motors.
AJ
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Old Nov 23, 2010, 08:40 PM
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Lincoln, CA
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WELCOME to the THREAD!!!

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Originally Posted by the man View Post
What is a safe way of Painting Sky Surfer?
I am sure you will get a lot of "right" answers to this one. If you want to add almost 0 g to the AUW, then use magic markers to slowly paint/stain the colors in place. Otherwise, you can use rattle can paint if you desire. Using water based paints will potentially add a lot of weight to the plane. Just my .02 worth. Again, welcome to the thread. There are a lot of very nice and knowledgeable folks here to help you if you need it. So, kick back, relax, and have a great time here.
AJ
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Old Nov 23, 2010, 09:05 PM
Crashasaurus Dumbthumus
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USA, MN, Apple Valley
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Quote:
Originally Posted by ajbaker View Post
Your posts and articulation of RC flying. If you said you were brand new at RC flying, I would not believe you. Can you please measure the Kv of the motors that you intend to use? I am curious about the most recent two motors.
AJ
Thanks for the kind words. The inrunner I ordered is 2200kv. That's the only one I'm sure about (from the Heads Up RC specs). I have no idea what the stock SS motor is rated and the current one on my second SS is stated to be 2810kv which is obviously wrong. I don't have a clue on how to figure out the kv on brushless motors.
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Old Nov 23, 2010, 09:09 PM
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What kind of rattle can paint?
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Old Nov 23, 2010, 09:48 PM
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Canton, Michigan USA
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Quote:
Originally Posted by the man View Post
What is a safe way of Painting Sky Surfer?
I use automotive acrylic enamal paint made by Duplicolor. It dries with matte finish and then I topcoat with clear, water based acrylic (Future).

Here is what an elapor (proprietary epo / epp from Multiplex) looks like with chrome yellow. It is very important to clean the foam with rubbing alcohol to remove any mold release agent.
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Old Nov 23, 2010, 10:25 PM
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Lincoln, CA
Joined Oct 2006
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Paint stuff

Quote:
Originally Posted by the man View Post
What kind of rattle can paint?
Read Prof100's post. He made an excellent suggestion and one that is quite popular. Oh, I will add my .02 worth. He referred to "Future" which is a floor polish available in most grocery stores. You will see WBPU referred to a lot also. It stands for Water Based PolyUrethane. Therefore, it would be OK to call "Future" a WBPU.
Rattle can paint is the old standard paint in a can with a ball-bearing inside to help "stir up" the paint when you shake it. Neat name, Huh?
Rustoleum paint from Home Depot is also popular. There is some other acrylic paint from Home Depot that is popular, too. I can't remember the name of it just now. Anyone else remember the name of it? I sure there are many other paints that work equally as well. Also, you might try an air brush. They are very cheap at Harbor Freight. There are a couple cheaper than the one I suggested (which I use often). But, they are not as good IMO.
Hey you guys - Any other suggestions that you think will help him?
AJ
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Last edited by ajbaker; Nov 23, 2010 at 11:52 PM. Reason: typos
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Old Nov 23, 2010, 10:25 PM
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West Texas USA
Joined Mar 2008
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Quote:
I use automotive acrylic enamal paint made by Duplicolor. It dries with matte finish and then I topcoat with clear, water based acrylic (Future).
Wow. That looks good for rattle can painting. I've been brushing on the art type acrylic stuff with a foam brush but it doesn't look that good.
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