Best ARF glider?
07-24-2009, 03:44 PM
#29
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RE: Best ARF glider?
Well the funny thing is that this is the model that got caught in lift, went into a cloudbase. Exceeded terminal vilocity, blew a wingtip off. Spent the night at the edge of a march. Was found the next day, thanks to a locator, then returned to me. Proving the worth of both your contact information, and electronic locators. My onbord altimiter recorded 4144ft above launch. My plans were to change the color of the wing bottoms, and add spoilers this winter. Now I can incorperate them in the repair. The fuse stuck into the soft marsh bottom, without even breacking the prop. All the electronics are fine, small crack behind the wing.
People say the ARF has a soft center section, I disagree. My wingtip folded due to speed. I was probably going 70mi/hr accross the sky looking for sink. Absolutly no fault of the BOT, simply my greed. My goal was to record 200ft. By that time the lift was to great. never thought that I would say that!
Again this is a great combination, only took me 2 days to cut, and get to flying state. Once I proved the angles, and concept. I finished it up a bit with some bondo, and painted it the next weekend. This wasn't the first time I got stuck in lift with it. It likes to fly fast, and it goes up really good. It sure is a hot gusty day glider. Don't let the 70oz scare you, but it does need spoilers.
I have been toying with the idea of doing a thread on spoiler installation to the Bird of Time, with the remaining original wing panel. This would to show people how easy a mod this is once you get past the "cutting it open" thought.
People say the ARF has a soft center section, I disagree. My wingtip folded due to speed. I was probably going 70mi/hr accross the sky looking for sink. Absolutly no fault of the BOT, simply my greed. My goal was to record 200ft. By that time the lift was to great. never thought that I would say that!
Again this is a great combination, only took me 2 days to cut, and get to flying state. Once I proved the angles, and concept. I finished it up a bit with some bondo, and painted it the next weekend. This wasn't the first time I got stuck in lift with it. It likes to fly fast, and it goes up really good. It sure is a hot gusty day glider. Don't let the 70oz scare you, but it does need spoilers.
I have been toying with the idea of doing a thread on spoiler installation to the Bird of Time, with the remaining original wing panel. This would to show people how easy a mod this is once you get past the "cutting it open" thought.
07-24-2009, 08:24 PM
#32
RE: Best ARF glider?
ORIGINAL: squeakalong
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..
)? Thanks for the help my friend!
Soft landings.
Joe
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..
)? Thanks for the help my friend!Soft landings.
Joe
Inrunners, like most motors you would think of, have the spinning part inside the can. These are usually high kV motors meaning high RPMs per volt applied. When turning propellers they can turn small props very fast. However for sailplanes, we are not looking for speed we are looking for steep climb. So we prefer big propellers. IN order to use an inruner you typically need a gearbox to step down the speed and multiply hte torque to handle the big prop.
NOTHING WRONG WITH AN INRUNNER AND A GEARBOX. They work extremely well. They also avoid any moving parts outside the casings. Finally, if you use the right gearbox, they can be quite slim and fit into narrow spaces.
Outrunners have the spinning part on the outside. They tend to be lower kV motors that can spin big props without a gearbox. Because there is not gearbox they also tend to be a bit quieter. So we eliminate the need for a gearbox, but we have to deal with the spinning can.
I prefer to do away with the gearbox and deal with the spinning can. Just a personal preference.
07-25-2009, 07:44 AM
#33
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RE: Best ARF glider?
aeajr: Thanks once again for the explanation of the differences in using one type of motor over the other. I can readily understand the need for a larger prop in this case and the outrunner does make sense. I truly appreciate your taking the time to assist!
Soft landings.
Joe
Soft landings.
Joe
07-25-2009, 10:11 AM
#34
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RE: Best ARF glider?
ORIGINAL: aeajr
We are going to talk in general terms here.
Inrunners, like most motors you would think of, have the spinning part inside the can. These are usually high kV motors meaning high RPMs per volt applied. When turning propellers they can turn small props very fast. However for sailplanes, we are not looking for speed we are looking for steep climb. So we prefer big propellers. IN order to use an inruner you typically need a gearbox to step down the speed and multiply hte torque to handle the big prop.
NOTHING WRONG WITH AN INRUNNER AND A GEARBOX. They work extremely well. They also avoid any moving parts outside the casings. Finally, if you use the right gearbox, they can be quite slim and fit into narrow spaces.
Outrunners have the spinning part on the outside. They tend to be lower kV motors that can spin big props without a gearbox. Because there is not gearbox they also tend to be a bit quieter. So we eliminate the need for a gearbox, but we have to deal with the spinning can.
I prefer to do away with the gearbox and deal with the spinning can. Just a personal preference.
ORIGINAL: squeakalong
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..)? Thanks for the help my friend!
Soft landings.
Joe
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..
)? Thanks for the help my friend!Soft landings.
Joe
Inrunners, like most motors you would think of, have the spinning part inside the can. These are usually high kV motors meaning high RPMs per volt applied. When turning propellers they can turn small props very fast. However for sailplanes, we are not looking for speed we are looking for steep climb. So we prefer big propellers. IN order to use an inruner you typically need a gearbox to step down the speed and multiply hte torque to handle the big prop.
NOTHING WRONG WITH AN INRUNNER AND A GEARBOX. They work extremely well. They also avoid any moving parts outside the casings. Finally, if you use the right gearbox, they can be quite slim and fit into narrow spaces.
Outrunners have the spinning part on the outside. They tend to be lower kV motors that can spin big props without a gearbox. Because there is not gearbox they also tend to be a bit quieter. So we eliminate the need for a gearbox, but we have to deal with the spinning can.
I prefer to do away with the gearbox and deal with the spinning can. Just a personal preference.
I think that your post is not exactly fair to inrunners. Even if it is in general terms. I fly 1.5 and 2 meter sailplanes with inrunner brush less motors as a matter of routine. And not one of them has a gear box. They go up like rockets and have great efficiency with respect to power consumption. And they are easy to install. I do use higher end brush less inrunners. My preference is not to deal with spinning cans nor gearboxes on my sailplanes.
Note: aeajr I read most of your posts and you contribute a bunch of great information. But on inrunners at least for the smaller sailplanes you are a little off base.
Todd
07-25-2009, 12:25 PM
#35
RE: Best ARF glider?
ORIGINAL: sawdust
I think that your post is not exactly fair to inrunners. Even if it is in general terms. I fly 1.5 and 2 meter sailplanes with inrunner brush less motors as a matter of routine. And not one of them has a gear box. They go up like rockets and have great efficiency with respect to power consumption. And they are easy to install. I do use higher end brush less inrunners. My preference is not to deal with spinning cans nor gearboxes on my sailplanes.
Note: aeajr I read most of your posts and you contribute a bunch of great information. But on inrunners at least for the smaller sailplanes you are a little off base.
Todd
ORIGINAL: aeajr
We are going to talk in general terms here.
Inrunners, like most motors you would think of, have the spinning part inside the can. These are usually high kV motors meaning high RPMs per volt applied. When turning propellers they can turn small props very fast. However for sailplanes, we are not looking for speed we are looking for steep climb. So we prefer big propellers. IN order to use an inruner you typically need a gearbox to step down the speed and multiply hte torque to handle the big prop.
NOTHING WRONG WITH AN INRUNNER AND A GEARBOX. They work extremely well. They also avoid any moving parts outside the casings. Finally, if you use the right gearbox, they can be quite slim and fit into narrow spaces.
Outrunners have the spinning part on the outside. They tend to be lower kV motors that can spin big props without a gearbox. Because there is not gearbox they also tend to be a bit quieter. So we eliminate the need for a gearbox, but we have to deal with the spinning can.
I prefer to do away with the gearbox and deal with the spinning can. Just a personal preference.
ORIGINAL: squeakalong
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..)? Thanks for the help my friend!
Soft landings.
Joe
You did a fine job with lots of info to get these old grey cells going. One question: why use an outrunner type motor (remember I'm new at this..
)? Thanks for the help my friend!Soft landings.
Joe
Inrunners, like most motors you would think of, have the spinning part inside the can. These are usually high kV motors meaning high RPMs per volt applied. When turning propellers they can turn small props very fast. However for sailplanes, we are not looking for speed we are looking for steep climb. So we prefer big propellers. IN order to use an inruner you typically need a gearbox to step down the speed and multiply hte torque to handle the big prop.
NOTHING WRONG WITH AN INRUNNER AND A GEARBOX. They work extremely well. They also avoid any moving parts outside the casings. Finally, if you use the right gearbox, they can be quite slim and fit into narrow spaces.
Outrunners have the spinning part on the outside. They tend to be lower kV motors that can spin big props without a gearbox. Because there is not gearbox they also tend to be a bit quieter. So we eliminate the need for a gearbox, but we have to deal with the spinning can.
I prefer to do away with the gearbox and deal with the spinning can. Just a personal preference.
I think that your post is not exactly fair to inrunners. Even if it is in general terms. I fly 1.5 and 2 meter sailplanes with inrunner brush less motors as a matter of routine. And not one of them has a gear box. They go up like rockets and have great efficiency with respect to power consumption. And they are easy to install. I do use higher end brush less inrunners. My preference is not to deal with spinning cans nor gearboxes on my sailplanes.
Note: aeajr I read most of your posts and you contribute a bunch of great information. But on inrunners at least for the smaller sailplanes you are a little off base.
Todd
Good point Todd. You are right, what you pick is application dependent. However look at context. He is asking about putting a motor in a 3M Bird of time that weighs 60 ounces, not a 1.5M glider that may weigh 12 ounces. BIG difference.
But let's use your planes as a case study. On you 1.5M glides, what inrunner do you use. What prop and what battery? What is the rated wattage for that combo?
This will serve as a case study to demonstrate how motors are sized.
08-16-2009, 08:51 AM
#36
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RE: Best ARF glider?
I couldn't be more pleased with the converted BOT using AXI 2820-14 with 13 X 6 folder. It is a silky smooth flyer, seems to stay up on its looks. 1 hour flights are a regular event using less than 1 Ah of battery power. I inhereted this one from a club member that didn't want to repair it after an incident with a very tall pine tree. Dings in the wing, fiberglass fuselage broken in half, stabilizer joiners bent, etc. About 20 hours of TLC and I have a keeper.
