Parramatta Radio Control Aircraft Club

Very very nice! Are my maths right when a 12V 22amp battery should give 9-10 2200mAh 11.1V charges?

kizza42 Wrote:Very very nice! Are my maths right when a 12V 22amp battery should give 9-10 2200mAh 11.1V charges?

Dependant how flat battery is but i should get no problem at least 9 x 2200mah charges.

I saw the bag at Mitre 10 and straight away i thought how cool is this, perfect for want i wanted it for.

your bag looks great steve, its a good setup

Hi Steve

Think your bag is great, may end up doing something similar.
I've got a question for you about batteries.
I found a maintenance free battery that I used to use in the field with my computerized
telescope. As I haven't used it for awhile I'm not sure if it's still any good.
I've had it on the trickle charger now for 3 days and the led on the charger is still
flashing indicating that it's charging.
The specs of the battery are DM12-4.2 (12V 4.2AH/20Hours)
not sure if I understand this correctly but do those specs indicate that at full charge
the battery will deliver 12volts at the rate of 4.2amps every hour for 20 hours?
If so, this little beauty will do me down the field every day without the need to use my car battery.
Of course what I don't know is how good the battery is after being unused for so long.
How long do you reckon I should leave it on the trickle charge ?
Specs of the charge are Input 240V Output 12V 350mA.
Both were bought at the same time from Jaycar.

Paul

listens in with interest.... :geek:

Ok Steve now I've confused myself.
After sending the question to you I looked up a Jaycar catalogue
to see what it said about the battery and charger.

First thing I notice about the battery it said to never leave the battery in a discharged state
for more than a few months.
Now I know that the battery was in a fully charged state when I stored it but that was something like
2 years ago. I guess the battery would somehow discharge itself over that time?.

Next thing I notice was about the charger I'm using.
Catalogue says that this charger is fully automatic in as much as it will switch to
trickle charge when the battery is charged, and the led will flash when the unit is operating in a
trickle charge state.
The led has been flashing ever since I started it, so on that basis the battery is still fully charged
even after all this time.

Does this seem reasonable to you?

Paul

What model is it?

Battery is DiaMec 4.2 Amp Hour 12 Volt. Jaycar Cat No: SB-2484 (Sealed Lead Acid Battery)
Charger is 12V 350mA Jaycar Cat No: MB-3517

Paul

paulj Wrote:Battery is DiaMec 4.2 Amp Hour 12 Volt. Jaycar Cat No: SB-2484 (Sealed Lead Acid Battery)
Charger is 12V 350mA Jaycar Cat No: MB-3517

Paul

Hi Paul.

Unfortunately the way they label them is mis leading.

You will only get 4.2amps out of the battery for 1 hour if you are lucky, normally 90% thus approx 3.8 amps
The reason for the 20 amp hour label info is that they say the battery can deliver with good safe working voltage for 20 hours but at 210ma only (4.2 amps divided by 20)
EG. Alarm system only needs approx 200ma to run off battery back up but the voltage must not drop below a safe level or will cause problems.
normal battery's will deliver the amps but the voltage drop well below desirable levels.

EG. My 22AH Battery will deliver 1.1ah for 20 hours comfortable.
Therefore i could charge battery's drawing 2200ma for about 10 hours so about 10 battery charges. But i expect probably only will gives
me 9 x 2200ma battery charges

So that battery 12v 4.2amp in theory could give you two charges of 2200ma battery's and then be flat.

Some info

http://www.powerintratech.com/lead-acid-...12-4.2.gif

http://www.jaycar.com.au/images_uploaded/recharge.pdf

Thanks for that Steve.
I thought that it was too good to be true.
As it was just lying around I thought I would give it a try.

Paul

Look what i got up too in a couple of hours after dinner tonight

[youtube]http://www.youtube.com/watch?v=N0CDeMMvepw[/youtube]

All planes ready for flight this weekend even my Funjet after little mishap in the wind and the tumble landing.

Looking good for the parachute drops mate.
I'll have to give a bit of thought as to which plane
I need to modify. Somehow can't see the Electrafun as being the one
Funjet looks good is that a new airframe you have there?

Paul

Bahahahhaa,

Great job with the drop hatch mate! Will be interesting to see how much drag it generates, you might want to limit its deployment to 30 or 40 degrees. The plane could literally fall out of flight!

Quote:Great job with the drop hatch mate! Will be interesting to see how much drag it generates, you might want to limit its deployment to 30 or 40 degrees. The plane could literally fall out of flight!

Thanks Guys
Very good point, i didn't take that into consideration with the opening of hatch that much, easily adjusted though on curve settings.
Yes parachute man will want to jump out all the time with the way i fly "No Guts No Glory" :mrgreen:
Parachute man didn't even want to get in the hatch at first

lol thats awesome steve..

i have just the right little fella who would love to do some gi joe retrievel!
good work on the hatch it should be alot more acurate than having to pull inverted prior to drop..

Quote:lol thats awesome steve..

i have just the right little fella who would love to do some gi joe retrievel!
good work on the hatch it should be alot more acurate than having to pull inverted prior to drop..

Thanks, Yes hoping it will all work ok, did adjust hatch to open approx 40 degrees, and did a few drops tests inside like i did on video clip, seems to work ok.
Packing the parachute man i think needs to be right to fall out and open properly as the chutes are thin plastic and rigid a bit so it could get stuck in box but i think in flight it should be ok and hopefully parachute down nicely.

On Another Note
Speed records here i come, I think this is the ultimate motor for the Funjet ( can't wait to give it a run on the weekend wih APC 7x6e prop)
Just came in the mail today cost me approx $30 delivered, hong kong supplier.
I think the kv/amps/prop size that the motor has should work a treat, considering the stryker motor that im using at the moment is only 1880kv and 7x5e prop and that is fast.
The only thing im not sure of is the actual recommended model weight for motor to push as its says below for 450 class Ele. Heli. weight ?


EMAX HL2215/450 With Fan NEW



HL2215/450 is special one for the electirc helicopter 450 class, it has the best performance for 3D fly. It will your best choice the 450 calss Heli
Specification
No. Of cells 3-4* Li-Poly
RPM/V 3700
No load current / 10 V 0,5 A
Current capacity 40 A/60 s
Dimensions 22*15 mm
Shaft diameter 2.3/3.17 mm
Weight 62 g
Recomended model weight 450 class Ele. Heli.
Recomended prop without gearbox 6"-8"

will be interesting to see how that motor goes steve..

I think this prop will be a screamer on the Funjet if the new Heli motor goes well :P

https://www.apcprop.com/ProductDetails.a...de=LP07090

A-10 Has Grown Wheels, Dual Wheels Main and Single Front.
:?: Questioning :?:
Will it take off from the ground :?:
Will the Wheels stay on when landing :?:
Should i try and make a spring back front Wheel :?:
Maybe i should of left it the way it was without Wheels :?:

What diameter are the wheels :?:

Wheels are 50mm and 12mm wide, Any Bigger and they would scrap the under wing.

Speed Testing This Weekend Just Came in mail, will be able to set up on other planes as well, quite easy

50mm should be ok for the grass, Atleast you don't have to worry about prop strikes Wether or not you rip them out will depend on how they're attached and at what angle you land... For EG. Nose in at 90deg is probably not gonna do em any good

hey nice work on the wheels steve, i think 50 mm will be ok for the strip but i reckon the landings will need to be nice and smooth..

also very interested to see how that eagletree gadget goes...

Samste - looks good!
One other option for undercarriage is a dolly which you can leave on the ground, but you're looking at a belly-landing again with an arrangement like that of course. Interesting - look forward to seeing how it goes.
Cheers,
Steve

Thanks Steve, I Hope It Goes OK I guess the worst is that the Front Wheel comes off on Hard Landing as the back ones are quite secure
Still may try Making a Spring front wheel as shop ones are huge and thick.

My other little project that i whipped together tonight was a Buddy Box System from my 36mhz radios Mode 1 and Mode 2 Compatible
As my Son and Daughter want to learn to Fly as they have been practicing on Flight Sim, and now that i have a T28 Trojan the Island Hopper Has been brought back into the Ranks as a Trainer for the Kids.
With a quick swap of receiver to Fm 36mhz and Buddy box Radios.
Tested controls, works well, was quite easy to Modify.

Very cleaver chappie....................
Well done.

Paul

I was thinking about Front Wheel on A-10 while i was packing van for tomorrows work, and i saw some of my spare alligator clips in the garage.
5 min Fix up Presto i Think this should work better and less stress on body and Wheel on landings.

hey steve thats a great idea mate , im really interested to see how that front wheel goes

also awesome work on the buddy box!

Hopefully this wind will disappear for tommorow morning flying.

I flew for a little today to test out a My Customed Built trainer wing with a V shape Wing and Ailerons for easier flying for the Island Hopper,Pictured Below the wind made it a bit awkward though trimming out..
But it flew very well if you made it go out of control the v shape brought it back to more of a stable position with a little elevator.
Ailerons were less responsive,which will be good for the kids learning.



As for the Funjet Gave that a scream to make sure the positioning of my air speed indicator was correct, and have fixed it in position on the Funjet, Pictured below the Pivot tube positioning. this wasn't really bothered by the wind as it flew.
As i have ordered spare pivot tube and tubing to be able to use unit any anyone elses plane as well as my other planes by simply unpluging computer unit and pluging in to spare pivot tube and tubing.