isobig
Flying officer
Posts: 8 
|
Post by isobig on Aug 12, 2014 1:28:56 GMT 1
|
|
|
|
Post by hghost on Aug 13, 2014 2:25:08 GMT 1
Have never changed to Brushless set up, so can't give you any yea or nay about it...the SC with a brushed Motor can get 7 to 10 minute flights or more depending on ones throttle management...and flying ability.
Do not think you will get more than that with a Brushless set up, perhaps more speed, less time...but why would you want the SC to fly fast anyway ?
|
|
|
|
Post by flydiver on Aug 13, 2014 2:37:59 GMT 1
What do cars with more power and better acceleration get?
Worse gas mileage.
You don't get something for nothing in this sport.
Stock SC is a pretty good compromise between power and efficiency. They are at opposite ends of the spectrum.
I didn't see a battery on your list. The SC stock battery is adequate for the stock plane but that is all. With the 10x3.8 you are going from a 12A max system to a 16A max, a noticeable jump in power. If you use the throttle much you'll hammer that battery, especially since it's likely well used.
|
|
isobig
Flying officer
Posts: 8
|
Post by isobig on Aug 14, 2014 2:36:10 GMT 1
Sorry I have the stock battery, plus a Turnigy nano-tech 1300mah 25-50c and a Venom 2100mah 20c for it. I appreciate the the responses but I was expecting a bit of support, not negativity. Correct me if I am wrong but from all the posts I read on this upgrade, all I have seen is that you get more time with the brushless setup since it is more effecient than the stock setup. Just because it has more power doesn't mean you have to make use of it. I always thought of it this way - it takes a certain amount of energy for an aircraft to fly at a certain speed. This is the same no matter what motor/engine you use (all other factors being equal of course such as weight) so if you can generate that amount of energy more effeciently then you get longer flight time. The extra power would come into play for take-off to get in the air quicker. Once in the air you reduce throttle for cruising speed. Like I said I don't intend on pushing the SC faster than it was designed to handle. Maybe I misunderstood the dozens of posts on this subject somehow.
The car reference is not a fair comparison since larger internal combustion engines are less effecient in converting energy due to larger moving masses and friction forces. It is a well known fact that brushless motors are more effecient than brushed ones. Remove the gear box and you have another bump in effeciency.
I spologize if this sounds crass as it is not meant that way. As I mentioned, I am going by many posts I have seen on this upgrade and my own knowledge of how things work. If I am wrong I will find out soon enough once I get to test the brushless setup.
|
|
|
|
Post by Knackered Sailor on Aug 14, 2014 10:56:26 GMT 1
I don't think people are trying to be negative isobig just pointing out a few things from their experience. So here's your support mate ;-) if you want to do something different to your SC and it makes you happy or you enjoy the challenge of adapting then go ahead and have fun, that's what it's all about. lol
I think the thing to remember is that the SC is a lightweight little trainer and there's not much that can be done to it other than cosmetic. As hghost said the stock battery will give up to around 10 minutes flying time and with full concentration my experience shows that's really about enough. I did hollow out mine to take a 2200mah battery which will give around half an hour in the air but to be honest I always come down well before then as I'm either getting a bit bored or a stiff neck. :-)
|
|
|
|
Post by flydiver on Aug 14, 2014 15:32:31 GMT 1
It's amazing how sensitive men are about a chunk of foam they buy...  Depending on your perspective I'm either the "info guy" the "bad news" guy, or the "reality guy".  But, I'm generally right.  You know that old saying, "not everything you read on the net is true?" That applies to a lot of RC info. Just because a motor is brushless doesn't make it more efficient, in spite of all the guys that say it is. Depends of THE motor, the COMPONENTS, and HOW it was built. You can easily get cheap brushless motors with 60% efficiency, and decent brushed motors with 80% efficiency. I rewind motors, I test motors, I have the experience to know. A lot of these $5-20 brushless motors are not made very well. OTOH the power:weight ratio is better than a brushed so they seem more efficient IF you remove weight on the plane. You can't with the SC because of the way it's made without some very deliberate modifications that just about no one ever does. They just add MORE weight. You can get sites that claim 90% efficiency from their brushless motor. In those cases you should consider ALL the info on that motor suspect as it's d**n near impossible to create an electric motor that efficient. [Note-Jeff at HURC actually TESTS his motors so his testing is reasonably accurate. OTOH, he simply passes on the specs that the his sources give him so that info isn't always reality.] Many of the specification on many of the sites are somewhat "inflated" to completely bogus. Marketing sells in this sport since the average guy can't tell one battery/motor/ESC/receiver from another. If they work, they think they are great. Most folks have no way of quantitatively testing. So a lot of anecdotal info is passed around. Electric motors are constant speed devices that operate most efficiently at higher RPM's. Propellers are most efficient at LOW RPM's. So the most EFFICIENT electric setups are high RPM motors mated to gearboxes appropriate to swing a large prop. The SC is set up that way. But gearboxes are noisy and complicated so people avoid them since you can now buy brushless motors that will run at lower RPM's, AND they believe that they are inherently more efficient because everyone says they are. That's ONLY true if you compare identical size, weight, and RPM motors, which is almost never the case. The statement [It is a well known fact that brushless motors are more efficient than brushed ones. Remove the gear box and you have another bump in efficiency.] is very common but has so many contingencies that it's hard to support. For instance, a decent gearbox only removes a few % of the power through friction. OTOH it may contribute a whole lot by allowing a high RPM motor, a smaller+lighter motor, and a larger prop to be used because of gearing. Effectively, in your case, you are buying MORE motor with MORE power AND less weight. Will you like it? Absolutely. Will you get better 'battery mileage'. I kind of doubt it. You will get better performance (read that as acceleration with that prop) most likely. I won't even try to get into motor+battery compatibility and the so-called C-rating and the associate mire. That is a whole encyclopedia by itself. I will direct you to this site to expand your knowledge base a lot more. It's way better than the 'rumors' you get off these kind of forums. I suggest you book mark it and spend some quality time there. It takes about 6 months of reading a LOT to get a handle on the electrics. sites.google.com/site/tjinguytech/charging-how-tos/Flying is easy, the electrics are hard. |
|
|
|
Post by sham on Aug 14, 2014 18:38:13 GMT 1
I really don't understand why people mod the Supercub so much that it's a different plane. I mean, each to their own and everyone should follow their own path to enjoyment... And I don't want you to get all upset again.. But.
Its not a very well built machine. Oh, for what it is its great.. But the quality of the more powerful planes is much higher. It's not designed for power or speed. It's not designed for ailerons and tricks. It's a slow, lightweight, stable trainer that's so relaxing to fly that it's a real joy.
To make it do what you want and survive you have to spend and strengthen. As standard, it's tough enough but won't survive brushless power long without added weight.
Personally I would, and have, kept the Supercub standard and bought a second plane for similar cost to the modifications and I now have the plane you are trying to make AND a Supercub.
I love my Supercub. Which is why I've mostly left it alone.
|
|
|
|
Post by hghost on Aug 15, 2014 0:26:50 GMT 1
As I stated I have no experience changing the SC to Brushless set up ( nor do I really want to ) But the idea and expectations to achieve a goal is Ok, as long as it is a realistic one .
If you gain a few minutes that is Ok, but what's the difference ? If I flew in the clouds as many do, I could keep the Cub there for a half hour or more and I know that to be a fact. ( others here already know cause they do it all the time )
But I do not fly that way...and even when I am buzzing around, I can get 8-10+ minutes....and that is flying less than 15 feet from the ground
If I had a brushed motor doing the same I would not expect any longer flight times, a few seconds a few minutes ? who knows, but nothing I would get excited about.
And I am afraid you are going to learn that as well .
But Hey , Tinker with what you have, and enjoy as Sailor stated and have fun doing it....believe me I am all for experimenting and trying new things and seeing what will happen, just have fun. I have way to many projects going on and I have no clue about what I am doing sometimes.( But I am learning more )
But do not get upset if someone tells you the truth. No one here intentionally sets out to degrade or berate anyone.
Everyone gives Honest, open opinions and tries to give you information to help and to allow you to see facts from fiction mostly.
We all have to learn (some of us the hard way), but we learn nonetheless.
You soon find out before you jump and do, you ask those who know and have been there and than you make a rational decision based on facts , not speculations.
I say all the time on most all subjects..ask 10 people you will get 10 different answers most of the time. It is rare Two agree on one thing.
there are those here who know from experience and have a wealth of information and they gladly share it. It may not be what you wanted to hear, but it will be the truth.
Flydiver is the one most ask, ( including me ) to find out the facts . Experience speaks volumes. I can't tell you how i have learned just by asking and reading what he has given me to read and learn. I suggest you read the links they help 100%
But I agree with Sham as well, I don't get it either ? Why change out a SC from being what it is ? If you want a Cub with Ailerons,brushless,flaps,etc etc..Sport Cub is an alternative. But if you just want to see what it will do that's Ok to , But....be realistic in expectations...and don't get disappointed . Just have FUN....and do what you want to do....everyone is for that.
WE supply honest support...sorry you took it as a negative, because None of it as I read it, reads that way .
|
|
|
|
Post by flydiver on Aug 15, 2014 2:11:16 GMT 1
Addendum - generally you get more time from a brushless upgrade because by then you also give up on the stock battery, the lousy battery box, mod that also for more space, and go to a 2200mA battery. That's why people get more time > way more battery.
The stock SC battery is a low performer. If you demand too much with a higher power system it will degrade the battery and it fails sooner than a stock setup.
|
|
But, I'm generally right. 
