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Old Jul 19, 2012, 03:41 PM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
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Originally Posted by CFIMEI View Post
Yes grasshopper, very wrong! Using a LiPo in a free-range glider is one degree removed from prairie land arson! Why would anyone, needing nose weight, use a dangerous battery type .....
Um, you do need to remember that there are places in the world where a spot of combustion isn't going to burn the whole place down..... Austria for example. I use LiPo's on every one of my slope planes.

Chris
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Old Jul 19, 2012, 08:35 PM
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United States, CA, Camarillo
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Originally Posted by Woodstock 1 View Post
Um, you do need to remember that there are places in the world where a spot of combustion isn't going to burn the whole place down..... Austria for example. I use LiPo's on every one of my slope planes.

Chris
Yeah, you're right about not every place being a tinderbox. I didn't look at his QTH. I'm thinking about the Western U. S. which is getting drier & hotter by the seasons. Colorado, where one of the Speedo importers is located, had a monstrous series of wild fires last month. One almost burned the U. S. Air Force Academy where the majority of the student body cannot accept the reality of global heating & related weather distortion!

Every glider I have built, except for the last one, a modified "Hybrid", has needed nose weight. So why not use a safer, heavier battery type instead of added lead to achieve balance?
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Old Jul 20, 2012, 01:25 AM
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Austria, Stmk., Graz
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Originally Posted by CFIMEI View Post
Yes grasshopper, very wrong! Using a LiPo in a free-range glider is one degree removed from prairie land arson! Why would anyone, needing nose weight, use a dangerous battery type which has a much higher power density than NiMh? When I had a 1.4 I used a long shape factor 600 maH NiMh which fit better into the confined nose but I still had to use recast fishing weight lead to fill the deepest part of the nose cone. Came in at 21 .oz with a slightly rearward cg. Used digital servos which worked well but draw about twice the current of non-digital. Got a reliable 2.5 hrs air time with this setup.
Be gentle to the newbie grasshoppers

It's my first unpowered glider so I don't wanna make anything wrong and was trying to use the equipment I already have...

So I'll use as much AAA Eneloops as needed to balance the plane right and plug my BEC (up to 23V ggg) between the batteries and the receiver. Hoping that there's no need to add any lead but there should be place for it in the nose.
CG at about 80-82mm is correct??

So I'll start up my soldering iron this afternoon and try best I can

The legend of the burning Lipos goes on ggg
Never saw one burning after a crash and believe me I had a lot of them on my beginning.

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Old Jul 20, 2012, 01:19 PM
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NiMh vs. LiPo

Hello Folks!

By accurately reading this thread I found some pics and comments from GR8FOLDED.

He's using 4 pcs of 2/3A NiMh batteries (about 96 gramms) and a lot of lead in the nose.


My favored 3S 1000mAh Lipo including the BEC has about 100 gramms - so the weight of the used batteries is nearly the same.

Both of us have to add the same mass of lead into the nose (about 110-125 gramms I think) but I'm still able to relocate the Lipo for about 2,5cm.

So I think that I'm not gonna buy any NiMh battery because it's not really making sense at all.


Cheers
Tom
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Old Jul 20, 2012, 01:42 PM
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You will always hear the argument about lipos in gliders when you have folks from drier climates. There are other issues that can be argued, but if you have a wetter climate and fly safely, take your pick.

Lipos do cost less, especially when you have gear that can handle the higher voltages without the need for a BEC.
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Old Jul 20, 2012, 01:50 PM
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United States, NY, Hamburg
Joined Aug 2011
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I have never seen nicad/nimh receiver batteries start a fire but I have seen cordless drill batteries start a fire. I suppose in the right conditions a rx battery wires could short in a crash and stat a fire. In the old days of huge nicad motor packs, they could definately start a fire.
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Old Jul 20, 2012, 09:17 PM
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NiMh vs. LiPo

The battery forum has discussed this subject all the way to the planet Kolob & back. (If you don;t know where that is Willard Romney will be happy to update you!)

The "LiPo Fires are Real" is a permanent sticky there.

My personal summary is that the LiPos, by their physical structural nature, can be dented, punctured, deformed etc. & this can lead to an explosion of the battery's electro-chemical innards in a really spectacular pyrotechnic display, with nothing substantial to contain it. Alternatively, NiMh's are encased in solid steel alloy cans & even if really mutilated & shorted internally do not self destruct in an external exothermic reaction. Sure, if some circuit supplied by the NiMh were to be culminated in some small conducting wire or whatever that was carrying the full shorted current of the battery & did not instantly "fuse out", opening the circuit, but remained red hot for a while, that could set fire to grass, balsa, etc. Rubbing two sticks together vigorously could give the same result.
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Old Jul 24, 2012, 12:55 AM
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Originally Posted by slope junkie View Post
Hey I found this:

http://www.petame.gr/forumv/showthre...=R2hobbies.com

"grew to 1.40 and for me omorfine
space of electronic clearly more comfortable http://www.r2hobbies.com/eng/proddet...pl3901006_code
Judging from its predecessor that we saw on many flights and this model should be a lot promising"

Here is the movie:

speedo (2 min 9 sec)


That' s a cool glider!
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Old Jul 25, 2012, 12:36 AM
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Greece, Attica, Athens
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Originally Posted by Moony7 View Post
Hey I found this:

http://www.petame.gr/forumv/showthre...=R2hobbies.com

"grew to 1.40 and for me omorfine
space of electronic clearly more comfortable http://www.r2hobbies.com/eng/proddet...pl3901006_code
Judging from its predecessor that we saw on many flights and this model should be a lot promising"
That was the thread I started for the 1.2m Speedo in the Greek "Petame" (WeFly) forum. The comment was about the new 1.43m Speedo...

Both are really good. I am sticking to the old 1.2m Speedos since they fit in the trunk of my car easily.
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Old Jul 25, 2012, 03:56 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
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I sold on my unbuilt kit of the 1.4; I'm sticking with the 1.2 as well.

Chris
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Old Aug 05, 2012, 12:32 PM
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Albany, CA
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I flew my Speedo Pro yesterday in 40+ mph winds w/ ~7 oz. of ballast. The wings did not come off! It's a very stable flyer. I like it more each time I fly it. I'd go for the fully molded one just because it's only $50 extra, but the built up one is still a screaming deal.
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Old Aug 14, 2012, 06:20 AM
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Wow! pretty nice "Jart-style" fuse landed )
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Old Aug 14, 2012, 09:02 PM
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I Just saw this too..... Too bad they don't just sell two versions of the kit as well.
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Old Aug 16, 2012, 09:57 PM
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Lipo Hazard

http://www.vcstar.com/news/2012/aug/...-park-anymore/

Article from the local throwaway about a (powered) model flying spot a few miles away from me that is shutting down over actual Lipo triggered brush fires & perceived future hazard.
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Old Aug 17, 2012, 02:55 AM
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Quote:
Originally Posted by CFIMEI View Post
http://www.vcstar.com/news/2012/aug/...-park-anymore/

Article from the local throwaway about a (powered) model flying spot a few miles away from me that is shutting down over actual Lipo triggered brush fires & perceived future hazard.
Worth reading though: seems there might be other motives at play...

I have still yet to see a lipo fire, and they don't call me "Crasherchris" for nothing...
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