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Another Tiny Trainer Build “Foamasaurus Wreck”

PoorManRC

Well-known member
#41
I would definitely recommend LiFePo4!! Much more stable, don't have to worry about keeping a "storage charge" until you're ready to use it, and they DON'T catch Fire!! Something much more important with something that you're holding in your hands!! :eek:
 

d8veh

Well-known member
#42
I would definitely recommend LiFePo4!! Much more stable, don't have to worry about keeping a "storage charge" until you're ready to use it, and they DON'T catch Fire!! Something much more important with something that you're holding in your hands!! :eek:
Unfortunately, there's a bit more to it than that. If LiFePO4 was a viable option, we'd all be using them, but they're not. There are too many practical limitations that make them less suitable than lipos. They're probably OK for an RC truck or boat, but I wouldn't recommend them for aircraft.
 

CarolineTyler

Well-known member
#43
Unfortunately, there's a bit more to it than that. If LiFePO4 was a viable option, we'd all be using them, but they're not. There are too many practical limitations that make them less suitable than lipos. They're probably OK for an RC truck or boat, but I wouldn't recommend them for aircraft.
But REALLY good for transmitters where the higher internal resistance and lower C rating is not a problem! They have low leakage and no storage voltage hassle.
 

d8veh

Well-known member
#44
But REALLY good for transmitters where the higher internal resistance and lower C rating is not a problem! They have low leakage and no storage voltage hassle.
Here's how I see it: C-rating isn't a problem for the transmitter battery, but the sudden voltage collapse is a bit dodgy. A lipo or nihm goes down more or less linearly so you can see what state of charge you have, but LiFePO4 goes down very slowly, then suddenly drops off a cliff. Personally, for the small advantage you get from LiFePO4, I wouldn't want to run the higher risk of my plane suddenly dropping out of the sky. You could mitigate the risk by careful charging procedures, but why would you want all that hassle and worry to solve a problem that doesn't exist. How many guys do you know who had their transmitter catch fire because they had a lipo in it?
 

PoorManRC

Well-known member
#47
Unfortunately, there's a bit more to it than that. If LiFePO4 was a viable option, we'd all be using them, but they're not. There are too many practical limitations that make them less suitable than lipos. They're probably OK for an RC truck or boat, but I wouldn't recommend them for aircraft.
Just FYI, they'd be terrible for RC Trucks!! My average Batteries to run my vehicles have a 75-100C Discharge Rating.
I use LiFePo4 in my Transmitters with great success! ;)
 

PoorManRC

Well-known member
#48
In other news I did some more mods. I added landing gear and a belly camera. I used 2mm wire for the undercarriage and the lightest wheels I had. Camera is a cheap one that was 11g.
Back on subject..... That looks GREAT!!! The Landing Gear looks good and sturdy too. How did you attach it to the Fuse??

...... I had to clear my point up above. Didn't want anyone thinking.... :cool:
 

FDS

Well-known member
#49
It’s slotted inside, like in the Scout. There’s a double skin there which is ideal. It didn’t hit the CG too hard as the camera can be moved on its mount forward or back to help and I had space to mount the battery backwards.
 

d8veh

Well-known member
#50
Just FYI, they'd be terrible for RC Trucks!! My average Batteries to run my vehicles have a 75-100C Discharge Rating.
I use LiFePo4 in my Transmitters with great success! ;)
I was referring more to using them for transmitters and receivers rather than motors. With a truck, if your transmitter battery goes flat, your truck goes failsafe, which is a lot safer than it would be for an aeroplane.
 

PoorManRC

Well-known member
#51
........ if your transmitter battery goes flat, your truck goes failsafe, which is a lot safer than it would be for an aeroplane.
You could not be more correct on that one!! (Although I DID once have a truck lose Transmitter signal - and that Rig fired straight into the Colorado River!!!) :oops::eek::mad:

That was still running AA Alkaline Batteries.
Since being exposed to LiFePo4 Batteries, I've NEVER had an issue. I also with Ground RC, run a Futaba 3PV and 4PX - BOTH with alarms, triggered by lower discharge as well as lower voltage! (I USED to have money).....

I have an older Flysky GT-T6 Radio for my budding Aircraft Hobby. I can't tell you if it has ANY Alarm at all!!! I can't get past the horrible Chinglish. :p:(

I've also seen that C ratings on LiFePo4 Batteries have increased in recent years. I still wouldn't power a Vehicle..... But when you get into the larger, 8+ Channel Radios, does C rating matter as much?
Are they going to draw THAT much current, that a Lipo is necessary?
 

buzzbomb

I know nothing!
#54
That was intense! So many "No Crash" zones over the hedgerows. Fixed wing FPV is pretty scary to me anyway. That was crazy. Your soundtrack just didn't do it justice. Wagner's "Flight of the Valkyries" would have been more fitting! Thank you, man. That was awesome. (y)
 

FDS

Well-known member
#55
The field isn’t very large by US standards, but it’s the nearest spot to home.
I usually fly higher there to give me options should something go wrong. The camera is not FPV, I will get round to sone FPV flying eventually but not there.
I got an invite to a local guys private flying field this week, to see some 1/4 scale gassers and fly on their farm.
 

buzzbomb

I know nothing!
#56
The field isn’t very large by US standards, but it’s the nearest spot to home.
I usually fly higher there to give me options should something go wrong. The camera is not FPV, I will get round to sone FPV flying eventually but not there.
I got an invite to a local guys private flying field this week, to see some 1/4 scale gassers and fly on their farm.
Got it. Nose cam. Not FPV. Still pretty scary. It's kind of weird how flying higher is more scary, but flying lower is more dangerous. Darn but I love this hobby!

Yeah, given an AMA license, which I'm willing to do, I can go fly with my local versions of those guys here. I've got two accessible clubs actually. From the pictures on the web, they all fly the big, gas birds and to me it is extremely intimidating.

My little DTFB plane, with my little flying skills, trying to get time on the field with the Old Schoolers? Them all showing off their skills while I'm just trying to fly? Nah. I'll pass. I just need an open field and good weather to fly in. Then I'm happy.
 

FDS

Well-known member
#57
I am just about ready not to embarrass myself too badly. I can now land pretty cleanly and fly tidy circuits.
This video seems to be the only one I am going to get, I have tried 4 times to get more but the camera hasn’t recorded anything. I need to get better at operating it, the small size means the controls are really tiny and it doesn’t have a light to say it’s recording, which is really unhelpful.
 

FDS

Well-known member
#58
Here is a detailed look at my Tiny Trainer undercarriage, a few people have asked about it. The top is a C fold of two pieces of 5mm foamboard, wrapped around the undercarriage wire like the Sportster wheels are made. Wheel collars are zip ties held in with CA glue, as the hot glue kept falling off. Wire is 2mm music wire from K&S metals.
Here is the hole in the fuselage, under that is a vertical 12mm wide 50mm high slot in the inner skin of the nose, the gear slots in.
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Position of the slot.
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Wire gear and foamboard mounting block.
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Leg length
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Width. You could go a bit wider, mine came out a little narrow. It works but wider would be more stable. There’s a few degrees toe in on the wheels to help track straight.
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Wheels are 45mm x 18mm foam wheels, for 2mm wire. eBay supplied these.