I did a barrel roll in in a 737-700

Originally Posted by teookie

This thing is cool.

I like this, someone know what it is / are their planes for it?

Originally Posted by joesmith285

I was once told that a plane ejected its battery and on a fast dowline the prop spun very fast and back fed electricity into the system allowing for a quick flare to landing. I have no idea if this is true but would be fun to experiment with. I was told that if you use a starter for like nitro engines you could spin an electric motor and it would power the plane.

I highly doubt this is possible, just a rumor that I heard.

It worked for UTjason in a 68 velox. Confirmed with electric nitro starter after a safe no-battery and too-good-to-be-true landing.....at House Mountain.

Lucky I suppose...but if there'd been a separate RX pack, it would've never been required.

So all this brings up some interesting ideas... what happens then when you are in say a power off dive and the prop is spinning madly all by itself? Does the electricity generated by this backfeed the power produced by the ESC and risk causing problems to aircraft's power system?

Originally Posted by ryan_m

So all this brings up some interesting ideas... what happens then when you are in say a power off dive and the prop is spinning madly all by itself? Does the electricity generated by this backfeed the power produced by the ESC and risk causing problems to aircraft's power system?

I seem to recall that a similar situation killed the esc of a certain vr-1. The one rocket launched at Ohio huckfest a few years back. The prop was spinning so quickly on the upline, that the each no longer worked. Luckily, there was still power for the servos. I believe the plan had been to rocket launch it, then fly it with the lipo on board, but they ended up just gliding it down.

Originally Posted by ryan_m

So all this brings up some interesting ideas... what happens then when you are in say a power off dive and the prop is spinning madly all by itself? Does the electricity generated by this backfeed the power produced by the ESC and risk causing problems to aircraft's power system?

Someone needs to set up a data logger and test? Mike will do it.

The thing that baffles me with this, is that I thought the esc had a bunch of MOSFET's in it to turn power on and off to the different windings of the motor. How the heck to these things work in reverse? I guess there's a way...

Also, based on what I've read, back EMF is opposite to input voltage.

I was told by castle with rc car escs that when you hit the breaks it back feeds the electricity from the motor to the battery as the esc can not dissipate that much power at one time with out dumping it to the battery. A spinning motor is a generator.

If I move a servo back and forth with a capacitor plugged into the RX I can get the spektrum RX to flicker and light up if I have the TX on for it to connect to. The servo acts like a generator powering the RX and the capacitor makes it easier since its holds some of the charge like a temporary battery.

I plugged in a voltmeter to the RX and I could generate 4 volts by moving the servo back and forth. Its easy experiment on an rc car since they usually only have one servo and a capacitor plugged in

Originally Posted by DaOldGuy

I like this, someone know what it is / are their planes for it?

It's something I got bored and made, no plans. Sizing was more "hey this looks about right" than anything else. There are lot of videos & tips if you go to the "Foamies (Scratchbuilt)" forum and then look in the "Foamboard Scratchbuild University" thread. You buy a couple sheets of dollar tree foam board, covert them in packing tape, and hot glue them together. If you really want more info about the plane, send me a PM.

Originally Posted by Ace4

It's something I got bored and made, no plans. Sizing was more "hey this looks about right" than anything else. There are lot of videos & tips if you go to the "Foamies (Scratchbuilt)" forum and then look in the "Foamboard Scratchbuild University" thread. You buy a couple sheets of dollar tree foam board, covert them in packing tape, and hot glue them together. If you really want more info about the plane, send me a PM.

Thanks,... I will look around the thread and see what I can sort out. There is nothing wrong with winging it.

Originally Posted by losifanatic

I was told by castle with rc car escs that when you hit the breaks it back feeds the electricity from the motor to the battery as the esc can not dissipate that much power at one time with out dumping it to the battery. A spinning motor is a generator.

It's like Dynamic Braking or Regenerative Braking:

http://en.wikipedia.org/wiki/Regenerative_braking

It's the brushless aspect of airplane motors that confuses me. I understand how a brushed motor acts as a generator.

I guess that ESC's can work in reverse. They are such complicated little bits of tech that it surprises me.

Originally Posted by DaOldGuy

I like this, someone know what it is / are their planes for it?

It looks like the fuselage is made from a piece of ABS plastic gutter drain pipe. There used to be a couple of planes that were made from the stuff called the Duraplane, and the Durabat. The Duraplane was a sport trainer, and the Duabat was a more aerobatic version.....

Edit....I guess they are still made......Duraplane However, it seems the Durabat is now called the "Aerobat"...

SteveT

Originally Posted by SteveT.

It looks like the fuselage is made from a piece of ABS plastic gutter drain pipe. There used to be a couple of planes that were made from the stuff called the Duraplane, and the Durabat. The Duraplane was a sport trainer, and the Duabat was a more aerobatic version.....

Edit....I guess they are still made......Duraplane However, it seems the Durabat is now called the "Aerobat"...

SteveT

Hey, that was my first plane ever...I had the Taildragger version of the old Dura-plane...K&B .20 Sportster and 3 channel...