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proppastie

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three minute motor runs. A manned airplane is a whole other story.
As a power launch ultra lite glider system, 3 min would be fine. 10-15 min would be great for a launch and 10 min emergency to a better landing site.
 

nerobro

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When they measure the amp hours of LiPos, do they calculate to the low voltage limit (is it around 3.5 per cell or so?) or is it calculated to zero energy left in the cell?
Lipo's have a really useful, and interesting charge curve. When you get under say.. 3.1v per cell, there's essentially no power left in the cell. Nominal voltage for a lipo is 3.6v. Full charge is 4.2, but the meat of your useful power comes between say.. 3.9 and 3.4v per cell.

To give you some idea of how little power is in a Lipo between zero and 3.0v per cell, I accidentially flattened a 6000mah pack last week. To take it from 0v to 3.2v per cell, took 250mah. To get it from 3.2v to full charge, took 6200mah.
 

Tiger Tim

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Well today I learned something then. I had no idea how the internals of a LiPo worked, I just charge them and throw them in my little planes. Thanks!
 

pictsidhe

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Lipo's have a really useful, and interesting charge curve. When you get under say.. 3.1v per cell, there's essentially no power left in the cell. Nominal voltage for a lipo is 3.6v. Full charge is 4.2, but the meat of your useful power comes between say.. 3.9 and 3.4v per cell.

To give you some idea of how little power is in a Lipo between zero and 3.0v per cell, I accidentially flattened a 6000mah pack last week. To take it from 0v to 3.2v per cell, took 250mah. To get it from 3.2v to full charge, took 6200mah.
Running a LiPo dead flat, then charging it, is a great way to form dendrites. I wouldn't recommend that you ever have that pack anywhere a sudden fire would unduly bother you.
 

Tiger Tim

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Well, it looks like it works pretty well after all:
[video=youtube_share;eNSN6qet1kE]https://youtu.be/eNSN6qet1kE[/video]

Now I want an electric Sky Pup more than ever...
 

nerobro

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I want him to try a flight with the tape removed from the wings. I suspect he'll return to a wallowing nose high flight condition. .... now I type that, I think that sounds wildly unsafe.
 

Tiger Tim

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I want him to try a flight with the tape removed from the wings. I suspect he'll return to a wallowing nose high flight condition. .... now I type that, I think that sounds wildly unsafe.
His first flight (which has since been made private on YouTube) was done without gap seals between the wing panels. In the post-flight review Peter even mentioned the enormous amount of drag caused there but never made the connection to how the plane didn't fly well on those first crow hops. I suspect it's because the region behind the power curve isn't well understood by RC pilots.
 

nerobro

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I didn't catch him mentioning it. "behind the power curve" is not a thing most modern RC Pilots ever have to deal with. Though I come from a time when "electric" was synonymous with under powered. Boy did I get familiar with that area of the power curve. :)
 

TFF

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I think I probably flies better with the tape, but when he was test hopping in the middle of the night, I'm sure flying at an unlit airport with an UL would not be good for full tests since both are not legal. He made hops and proved it. I'm sure the new batteries that were not borrowed makes it much easier not to worry about buying someone else some new batteries. The question now is , this punk kid did it and on the internet, so why are all the experienced people behind?
 

nerobro

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He's exceedingly driven. He has time. He knows what "is enough" and doesn't get hung up on "perfect". He can ignore jerks. He's confident in his abilities. He has tools, and knows how to use them.

.... Very few builders have most of that. A large number of them are limited on time. Many more are limited on their ability to make engineering decisions. Others are obsessed with perfection. Others have budget concerns. Many are not able to stay focused.

That's were your other people are at. :)
 

BJC

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He's exceedingly driven. He has time. He knows what "is enough" and doesn't get hung up on "perfect". He can ignore jerks. He's confident in his abilities. He has tools, and knows how to use them.

.... Very few builders have most of that. A large number of them are limited on time. Many more are limited on their ability to make engineering decisions. Others are obsessed with perfection. Others have budget concerns. Many are not able to stay focused.

That's were your other people are at. :)
I expect to see him at Oshkosh with a new design in a few years.


BJC
 

BBerson

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The videos are not bad either.
Good to see some of the young can navigate the new world with new and different tools.
EAA should send an invitation.
 

proppastie

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I think I probably flies better with the tape, but when he was test hopping in the middle of the night, I'm sure flying at an unlit airport with an UL would not be good for full tests since both are not legal. He made hops and proved it. I'm sure the new batteries that were not borrowed makes it much easier not to worry about buying someone else some new batteries. The question now is , this punk kid did it and on the internet, so why are all the experienced people behind?
you forgot to mention how much fun he is having.....star of his own video, a crew of supporters. I would guess he has a lot more personality than most of us.
 

Topaz

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Moderator Update: The originally offending post was off-topic, argumentative, and a generalized personal attack against pretty much everyone in the forum. I've deleted it, and then removed the following posts that referenced or replied to it. Those replies were in order, but quoted and responded to a post that's being deleted, so have no context anymore. I've only "soft" deleted the posts, so if there are further issues, the moderators can reference the original posts for background.

Thread is now re-opened for posts on the original topic.
 

Hephaestus

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I really want to see further development like this... Makerplane, and this one make me smile inside - blue and pink foams seem so attainable and cost effective in comparison to more conventional methods. Yeah not perfect but a good basic material to put something structurally better over.

I really wish makerplane had started with a j3 copy, re-enginereed in this structural build style and kept moving forward.

Start looking at RC foamie builds, bring in some CNC hotwiring, and go into a direction similar to fold-a-plane... Using carbon prepregs, even a weekend hobbiest could be completing an airplane in months not years...
 
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