Thread Tools
Aug 23, 2019, 11:23 PM
always something to learn...
metalguy's Avatar
I maidened mine last week. I found that when the battery comes out in flight, it's self landing feature is a plus.
Big Navy NE-1 Cub maiden (4 min 23 sec)
Sign up now
to remove ads between posts
Aug 24, 2019, 08:22 AM
Head NEAT geek
Tom Hunt's Avatar
You just found out that even with a BEC, the freewheeling prop/motor acts like a generator and provides enough voltage to keep the RX alive. prop slows down to much, RX goes offline!

I watched a guy do this twice in as many weeks with an FMS P-40!
Last edited by Tom Hunt; Aug 26, 2019 at 07:21 AM.
Aug 25, 2019, 04:14 AM
what goes up, must come down..
AussieHoppy's Avatar
Quote:
Originally Posted by Tom Hunt
You just found out that even with a BEC, the frewheeling prop/motor acts like a generator and provides enough voltage to keep the RX alive. prop slows down to much, RX goes offline!

I watch a guy do this twice in as many weeks with an FMS P-40!
A freewheeling prop will generate up to 5v? And the esc will allow motor generated voltage to be back fed through to the bec? Does it convert 3 phase to dc, I guess? I would never have thought! Thanks for that, learn something new every day
Aug 25, 2019, 06:28 AM
Head NEAT geek
Tom Hunt's Avatar
Quote:
Originally Posted by AussieHoppy
A freewheeling prop will generate up to 5v? And the esc will allow motor generated voltage to be back fed through to the bec? Does it convert 3 phase to dc, I guess? I would never have thought! Thanks for that, learn something new every day
First the motor kv must be high enough to generate about 4v (most Rxs even the cheap ones can work at <4v) with a big enough prop windmilling at enough rpm. Some ESC's have built in diodes to not allow this to happen but many do not.

lastly, one must keep the speed up by using the energy of the weight of the model to fly steeply down to landing as at some point the prop will slow below creating enough voltage.

when my friend lost his battery for a second time in a week, he was plenty high and I told him to dive the airplane and wiggly the wings back and forth intentionally so that we could all see he was in control. he made a beautiful belly landing in the grass at a fairly low speed before the rx gave out.

Tom
Last edited by Tom Hunt; Aug 26, 2019 at 07:22 AM.
Aug 25, 2019, 06:48 AM
what goes up, must come down..
AussieHoppy's Avatar
Quote:
Originally Posted by Tom Hunt
First the motor kv must be high enough to generate about 4v (most Rxs even the cheap ones can work at <4v) with a big enough prop windmilling at enough rpm. Some ESC's have built in diodes to not allow this to happen but many do not.

lastly, one much keep the speed up by using the energy of the weight of the model to fly steeply down to landing as at some point the prop will slow below creating enough voltage.

when my friend lost his battery for a second time in a week, he was plenty high and I told him to dive the airplane and wiggly the wings back and forth intentionally so that we could all see he was in control. he made a beautiful belly landing in the grass at a fairly low speed before the rx gave out.

Tom
Thanks so much for explaining this Tom, I never knew this was possible. Another significant advantage over gassers lol
Aug 25, 2019, 07:24 AM
Head NEAT geek
Tom Hunt's Avatar
Quote:
Originally Posted by AussieHoppy
Thanks so much for explaining this Tom, I never knew this was possible. Another significant advantage over gassers lol
yes, but like practicing auto-rotation in a heli, I don't recommend doing this intentionally!
Aug 25, 2019, 07:39 AM
what goes up, must come down..
AussieHoppy's Avatar
Quote:
Originally Posted by Tom Hunt
yes, but like practicing auto-rotation in a heli, I don't recommend doing this intentionally!
Ha ha! I concur!
Aug 25, 2019, 09:23 PM
always something to learn...
metalguy's Avatar
Well that explains a lot. But the plane was pretty mild handling with the sudden CG change. I had to have it all the way forward to balance properly, so with it gone, it should have n
been falling like a leaf! At any rate, I am happy the damage is minimal, and will secure the battery better in future flights!--------Metalguy
Sep 01, 2019, 10:01 PM
always something to learn...
metalguy's Avatar
Two more flights today. Great flying plane, hardest part is transporting it! -----Metalguy
Sep 03, 2019, 10:18 AM
JohnVHRC
JohnVH's Avatar
Its a big boy!
Latest blog entry: 94,5" Navy Cub
Sep 03, 2019, 04:52 PM
Dont forget the velcro straps
corsair nut's Avatar
looks like a hoot!


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product H-King J3 Navy Cub (NE-1) 1400mm (PnP) TiredIronGRB Electric Warbirds 115 Oct 07, 2019 09:23 PM
Discussion 2400mm Navy Cub from Hobby King Kmot Scale ARF/RTF 6 Jun 27, 2019 01:29 PM
Discussion Phoenix Models Super Cub PA-18 GP/EP/Gas ARF 90.5" ode guy Scale ARF/RTF 1 Jun 27, 2018 12:59 PM
Discussion Tower Hobbies - Phoenix Model Piper J-3 Cub GP/EP/Gas ARF 90.5" easyrider604 Scale ARF/RTF 12 May 24, 2018 12:45 AM
Build Log Sig 1/5 Cub, built as U.S. Navy NE-1 Luftweenie Giant Scale Airplanes 3 Dec 16, 2014 03:19 PM