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Old Feb 20, 2003, 01:30 PM
Dax
There is no spoon
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Vancouver BC Canada
Joined Aug 2002
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hypethetical idea re: a never ending e-flight

I know you will all think I am crazy for this but here goes:

I am building a GWS TM and (im)patiently waiting for my 4 kokam 1020 cells from bpp to arive. I bought the TM and kokams purly because I wanted the 50 min flights that everone was talking about with their TM's

When all you have to do is wait for batteries, the mind wanders.....

acording to this thread: http://rcgroups.com/forums/showthrea...er+moth+kokams

with a triton charger it takes 40 mins to charge a pack.... and it flys for 50 mins

Perfect you think, right? I can fly all day! just have to land and change packs, fly whal the other one charges then land and change packs again!

*****But what if I don't want to land?*****

I think I have devised the first, mid air refuelable, TM!

Bear with me. Lets say I was to atach 4 neodium magnets to the to of the TM wing, 2 positive side up, and two negitive side up. Then I will run wires from the ESC to the magnets (they conduct electricity) Then I atach 4 similar magnets to the 2 cell 1020 kokam pack, with the power from the kokams flowing into the magnets. CG issues aside, this would work fine. place the battery pack on top of the plane and fly, pull it off and replace it, fly again.....

Now lets say I mount a servo atached to chanel 4 under the battery pack, so when hit it, the battery gets 'knocked off' the magnets. and I put two more magnets on the 'top' side of the battery pack, and two more magnets on the belly of another plane.

The mid air refuel goes something like this. fly the TM for 45 mins, remember the other pack takes 40 mins to charge, so you now have 5-10 mins of grace to complete the mid air refuel before the plane hits low voltage cut off. take the fresh pack off the charger atach it to the belly of the 'mother ship' with the aformentioned manets, ROG the mother ship. Now comes the tricky partyou need to line up the TM directly under the refueling plane. Eject the battery from the TM. The TM is now DEAD STICK! not just no motor, but no contol surfaces. It should hopefuly glide nicly forwards. Now with the big plane, you 'catch' the TM with the 4 magnets on the bottem of the battery pack. Now at the very least you have a hold of the TM and its not a free flight plane!

If all went well your 1st kokam pack is now floating down to earth on a small parachute of some kind and you TM now has power restored via the magnets. But the two plane are still atached right! fortunatly the batter is held onto the TM with 4 magnets and the mothership with only 2. So when the TM dives down, and the mothership pulls up, they should de-atach. And the battery should remain on the TM.

Now land the mothership and throw the first kokam on the charger. Lather, Rinse and Repeat!

If all goes well, you should be able to do this till you die from exaustion!


Now i'm not going to atempt this, but I thought I would throw it out there for everyone else to think about.

L8R
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Old Feb 20, 2003, 01:47 PM
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Please let us know the results if you try it.
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Old Feb 20, 2003, 02:00 PM
Hairy E-Pilot
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Ellensburg, Wa, USA
Joined Dec 2000
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YOU’RE CRAZY… It could never work. Next you’ll be telling us that a real plane could do the same thing with a hose hanging out the back of the bigger plane… or that you could put some guys in a rocket and send them up to walk on the moon… or that the earth is round!

Blasphemy... You should be stoned.

Gary
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Old Feb 20, 2003, 02:07 PM
Dax
There is no spoon
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Vancouver BC Canada
Joined Aug 2002
1,016 Posts
uhh, I am


What about adding a large capasitor between the battery and the esc. It wouldn't give you any juice to run the motor, but it would let you run the controll surfaces with no battery atached for a few mins.
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Last edited by Dax; Feb 20, 2003 at 02:15 PM.
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Old Feb 20, 2003, 02:40 PM
Lookin' Good. Real Good.
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London, Canada
Joined Aug 2002
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WHAT!!!!

That sounds good and fun..but I have a few questions. That;s gotta be some awfully good piloting skills, and just the littelst mistake will send you guys crashing down. How will you plug the batter(ies) in? I supose it will work through thos magnets, but I missed how it works. And the final concern....Longest flight = longest stick time = falling asleep at the sticks. I don'y suppose you could do this for more than three air to ar rejuicings. But then again, if it DOES work, then you need to contact Guiness world records for Longest R/C flight.

Try it, what do you have to lose?

You could hang on the battery until after the docking, just cut the motor out. That way you won't have to turn it into a free flight until you dock. that would make it less worrisome. Plus, if the other pilot missed you wouldn't have to walk so far cuz the plane could be returned.

My opinion!!

Cam

Good Luck Dax!!!

I agree, i think your nuts But where would R/C be without them?
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Old Feb 20, 2003, 03:44 PM
29 rods from you in western WI
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Joined Jan 2003
4,885 Posts
Hmm, I'm going in a few different directions here:

Option One
Trail a bare conductive wire from each wingtip. When juice is sagging, fly in contact with uninsulated high voltage power lines. With the proper converter you could charge your batteries before running into the next power pole, and off you go!

Option Two
Wrap miles of magnet wire (or extension cords) around the uprights of a football goal. When juice again gets low, energize the gigantic coils, creating a large magnetic field between the posts. With a proper receiving coil in the plane, you should be able to induce a current sufficient to recharge. Might need to loop several times through the uprights to complete the refueling.

Model plane: expensive.
Midair recharging: dangerous, illegal, expensive.

Wow-factor: Priceless.
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Old Feb 20, 2003, 04:11 PM
310mph Kolibri T25 Swist
henke's Avatar
Sverige, Kronobergs Län, Ljungby
Joined Jan 2001
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Dax!

that´ll be no problem!!

the real challange is if you fly both planes by your self



it would work to dock two planes and change batteri in mid air...
just think of a clever way to do the exchange... as you can´t fly that stable with two planes....


/Henke
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Old Feb 20, 2003, 04:24 PM
Professional idiot
Hampshire, UK
Joined Jun 2002
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Re: hypethetical idea re: a never ending e-flight

Quote:
Originally posted by Dax
acording to this thread: http://rcgroups.com/forums/showthrea...er+moth+kokams

with a triton charger it takes 40 mins to charge a pack.... and it flys for 50 mins
That 40 min was for a partially discharged pack. A rough calculation shows that approx 400-500mah was put in. I.E. it was already half charged.

Cool idea though.

You could have two packs on board, a small secondary pack used for the swap over.

--
Dave
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