Upgrading Prop to get more power...?

[jancoflyer]

I have been reading the other posts on props and i cant seem to figure out which prop is the best one for me. There are so many options, it would be helpful to know which one would work for my situation. I have the Supercub Lp all stock which comes stock with the 9x6 prop. I also got the floats for the plane and those came with the 10x8 prop. The 10x8 prop at full throttle makes my engine die because it draws too much power from the battery..at least that's what i have been told...so i would like a prop that gives me more thrust and power then the stock 9x6, but not more then the 10x8 prop that came with the floats. If anyone has any suggestion that would be very great. Thanks in advance:)

[kenninny]

Im know expert, but if your motor dies because you put on the 10x8 prop, you should check your battery. the 10x8 draws more amps, the 10x8 comes with the floats because the plane needs more power to take off from water, after your in the air you should throttle back, and fly at 50%, or you risk burning up the stock motor or esc or both.

[jancoflyer]

@ kenninny

I agree with you. I know that it is most likely that my batteries(stock) dont have enough amps for the 10x8 prop, but i have only flown the battery 4 times and charged it correctly so they "should" be able to handle it. Its very difficult to take off the water when once you almost get to full throttle it dies... I was hoping that someone would be able to tell me which prop would be better then the 9x6 stock prop and which type of prop would get to more power, but not as extreme as the 10x8 prop becasue my batteries cant handle it. If i comes down to it i will just end up buying a bigger battery, but first i would like to know if i could get more speed with a simple prop upgrade without having to spend more money on a bigger battery unless thats all that i really can do.

[kenninny]

Im not sure but I think the size of the pitch determens the draw of the amps,I would not go larger than a 10" prop the larger prop will move more air. but down size on the pitch, Try a 10x6, and see what happens,

[jancoflyer]

Thanks for the help. I ended up on just going and getting a bigger battery because i figured i was going to do it anyways so why put it off. I havent had a chance to try it out yet but hopefully it works for me.

[Dillzio]

Hey guys, I can help here

the size of the pitch has little to do with the amp draw, prop diamater, and type are the two main factors. Small changes in pitch (1-2 inches) have only a negligible effect on amp draw on the bench (max amp draw), although the lower the pitch, the less amps it will draw at speed, and the lower the models top speed will be.

The stock super cub props are so light they are on the border or being a slow-flier. For this reason, you'll be extremely hard pressed to find a more efficient prop. While some slow-fly propellers may give you more thrust, they would not be rated to be used safely on a super cub lp.

I don't think you're going to find any magic answers here, the stock 10x8 is the most powerful prop you can run on the stock setup, and even that would be pushing it. The 10x8 prop is so close to the borderline that constant flying at WOT, or upgrading to a more powerful lipo (and often both) will cause the stock ESC-receiver unit to burn out.

If you are using the recommended battery and it's brand new, that will have plenty of power to spin the 10x8 prop. If someone's telling you that your battery is too weak to run the 10x8 i'd be wondering if they actually have anything to suggest there's anything wrong with the battery - you did charge it right?
You would have to have a pretty bad battery to not be able to power the stock 10x8 prop, and if the battery was that bad it would cause the battery to puff up and get hot. The weak link in the stock cub setup is always the ESC/receiver box. It's notorious for burning out as it gets quite hot in operation, and the flying bigger props at higher throttle settings makes it burn out even faster. While sometimes the windings in the motor can burn out, that's easy to check for by looking inside the cage with a torch and smelling the inside of the cage. If it looks or smells burnt there's a problem.

I'm afraid the brains trust at hobbyzone have put together the absolutely most awesome package possible which has completely maximised the potential of the crappy cheap electrical components they use in the cub. Basically if you change any one thing to increase power the weak link of the system (the esc/receiver) will tend to crap itself. Because the esc is built into the receiver, and the servos only work with that receiver, to change either the servos, the esc or the receiver for anything better means swapping out the whole system. This is probably why the cub is one of the most widely modified models around.

I invite you to join the cub builders club, and make a cub to your own specifications. A brushless motor, ESC, radio and servos may only set you back about $100. Other than that I'm afraid you're stuck with the 10x8 prop and conservative throttle management.

If your motor is cutting out when you run it at WOT on a stock 10x8 prop with a stock battery then I'd suggest your ESC/receiver unit is faulty and needs to be replaced. Hobbyking's warranty policy is usually really good so contact them and they should be able to fix it up for you.

[jancoflyer]

Thanks for all the help guys. I talked to hobbyzone and they said they have been having the problem and they would look into finding a solution. After waiting for weeks with no reply i called back and they told me they never figured out why it was happening for sure, so they sent me a new ESC/reciever and it works now!!

[flydiver]

Same battery that was not seeming to perform well and the 10x8 prop?
Now it works? Or are there some other changes, like the larger battery?

[crashkopter]

How do I go about changing the prop from a 9x6 to a 10x8. There is a black cone then the prop how do I remove them and put the bigger prop on pease help

[hounddog]

The motor provided the power, the prop provides thrust and in doing so, drag.

Any propeller is a compromise and as in all things, it depends what you want.

A smaller pitch prop will perform more efficiently at low speeds and a higher pitch at higher speeds, albeit at the expense of takeoff and low speed performance.

If you are going for speed, bear in mind that drag increases as a square of velocity so for double the speed you require four times the power.
Increasing the pitch of the prop above that of the capability of your motor to provide enough power for the required airspeed will stop your motor reaching its rated RPM and result in overloading.

For better takeoff performance you would be better with a larger prop and a smaller pitch size, but as said, high speed performance would be out the window.

Until the RC world comes up with tiny variable pitch props, then you have to know what you want from it. Excellence in one area always comes at the expense of another,

[spindeepster]

Dec 31, 2012 13:00:31 GMT 1 hounddog said:

..... Excellence in one area always comes at the expense of another,

simply put!

[flydiver]

Dec 30, 2012 5:36:48 GMT 1 crashkopter said:

How do I go about changing the prop from a 9x6 to a 10x8. There is a black cone then the prop how do I remove them and put the bigger prop on pease help

Pull the stupid rubber thing off with pliers. Undo the nut. Put on the new prop. Now watch your ESC fry if you aren't careful. Read Dilzio's post again carefully.

[iandhunt]

Dec 31, 2012 17:09:50 GMT 1 flydiver said:

Dec 30, 2012 5:36:48 GMT 1 crashkopter said:

How do I go about changing the prop from a 9x6 to a 10x8. There is a black cone then the prop how do I remove them and put the bigger prop on pease help

Pull the stupid rubber thing off with pliers. Undo the nut. Put on the new prop. Now watch your ESC fry if you aren't careful. Read Dilzio's post again carefully.

Now watch your ESC fry?!?! Lol! Love it! Best response I have seen in a looooong time!

[flydiver]

I wish it was more funny. Pilots having a $50 ESC+RX die generally are puzzled and upset. Horizon would only give them proper guidance, right? .......NOT
Think about ACT. NO ONE but Horizon thinks it's a good product. It sells planes on the promise of saving you from crashing. Then it sells parts.

People not understanding the relation between motor+battery+prop would benefit from a careful read of this post:

Stock motor/prop/thread - Lets get it straight
supercubclub.proboards.com/index.cgi?action=display&board=motors&thread=4624

In electric there is no 'free power'. You need to work toward a balanced system. Each part affects the other parts in the power pack. You can't simply change one without thinking about the ramifications to the others.

Can you get away with the 'float prop/10x8'? Some do, some don't. Depends on the particular quality of YOUR plane and HOW you fly it.
Some of them die almost immediately. Some do OK. I can just about guarantee you that it will die if you like that extra power and find you have a heavy thumb. Unfortunately when if it does croak you have no control at all, generally meaning a crash of some sort.

[iandhunt]

I agree. The pilot and his/her style of flying are the two greatest factors in the survival of the electronics. That balancing act, for me personally, was a little bit tricky to get the hang of initially. New I feel better knowing I replaced the crappy electronics with a system I put together, soldered, and modified to suit my easy going flying style. My cub went from a blank canvas to an LED lighted piece of artwork. Thanks primarily going to these boards and people who learned the hard way and shared their misfortunes.