1/4th Piper J-3 Cub ARF -- Wing Span- 106 in

[jrb]

Is any one doing or flying the new Hangar 9 1/4th Piper J-3 Cub ARF -- Wing Span- 106 in?
http://www.horizonhobby.com/Products/Default.aspx?ProdID=HAN4550
Recommended:
Motor: E-Flite Power 110 Brushless Outrunner
Prop: 19x8E APC Propeller (APC19080E)
Speed Control: Castle Creations 85A High Voltage ESC
Battery: 2 (8S) Thunder Power 4S 5000mAh Li-Po (THP50004SX)

Thinking of A123-10S2P with 16x9 and these:
Motor: $116 -- http://www.bphobbies.com/view.asp?id=V450327&pid=B1898548
ESC: $69 -- http://www.bphobbies.com/view.asp?id=A0780193&pid=B2632604

[staggerwing]

There is a thread on one but I think not here in giant scale---try elec conversions

[hermperez]

That setup from BP with the 10s2p A123 pack should work well, probably with a 19"-22" prop.

Most of these large 1/4 scale Cubs are seldom flown at full throttle.. 1200 watts of power would be fine for them.. you can save some weight by going with a 4130 class motor and 8s2p A123 pack. An 8S A123 pack is about equivalent to a 7s lipo pack. In terms of gas, about a zenoah g26..

This motor:
http://www.bphobbies.com/view.asp?id=V450327&pid=B2171401

with a 16*8 prop, plenty of power.

The lighter you keep the Cub the slower it will fly.. more fun.

[mediq]

If you do a search in the conversion area i did one a month ago..plus onboard video

[jrb]

Thanks for the reminder of the other thread: http://www.rcgroups.com/forums/showthread.php?t=752795 .

I'm currently flying the older H9 80"/5th Cub on A123-5S2P & AXI 4130/16 via a 16x8 -- pulls less than 30amps; so nice long flights and very fast recharge!

I've previuosly had 16xIB4200 w/15x8; would fly inverted out of site.

Shed nearly 3/4# going to A123s! Now RTF is 9#.

I like to do big props @ 30amps WOT; that's why I was looking at the lower Kv & hence larger motor.

8S would save the wieght of 4 cells since I'll do 2P; was likely going to use two DeWalt bricks straight ot of their plastic shell.

My Mastech 5020 will give me a 20amp recharge; we have AC at the feild.

TIA,

Jim

[jrb]

I was very surprised myself just using 7s i was going to increase the cell count.
But it flies very scale and has no problem taking off thick grass .


Please confrim the size prop you are using w/7S and the E-Flite 110 BL?

[Rich Ness]

Jim,

You have me interested too. Have you made any decisions about gear? What is the street price of this plane?

Rich

[jrb]

Hi Rich!

Haven't seen you in while, nice to connect up here.

Sky/Warehouse has it for $489; that's a really good deal considering all you get! It was $100 to put Robart like mains on my 1/5 H9 Cub -- the 1/4 come with them.

Worked of the list in the manual and added a Spektum module w/7ch RX for my 9303 and that's another $480.

$200 for two DeWalt packs; and still haven't settled on a motor.

Seems "cheap" to get a Tower Pro/Balsa Pro for $100 when you consider all the above?


Quality & efficeincy speak to me for this project; but not at $400, still haven't found a Neu or other that I like either.


Do you have an idea for a motor?


Jim

PS: plan to go to TVRC mid pm; will have my 1/5 Cub on A123s there, FreeStyle on A123s, and not sure what else.

[hermperez]

A Cub does not need a lot of power unless you are flying from water or towing sailplanes.. an Axi 5330 series would be a nice motor for this plane, efficiency in the mid 80s and nice european quality. With two dewalt packs you would get 16 minutes of aerobatics and much longer just put-putting around. Prop it for around 1400watts.

You could also get a 5330 clone from UH for about $45.. in looks, functionality and build quality it is the same.


Seems "cheap" to get a Tower Pro/Balsa Pro for $100 when you consider all the above?
Quality & efficeincy speak to me for this project; but not at $400, still haven't found a Neu or other that I like either.

[AEROLIPE]

how much you pay for all?!

[jrb]

Got one from Hobbytown in Brooklyn Park today Rich; $460.

Jim

[Ron]

I see Axi has redesigned one of their 5320 motors for 6 lithium cells, and it looks like it will fly this model with ease.
check with Richard at www.pacificmodels.ca
it shows in the axi motor finder on their site, but doesn't come up when you ask to see the setup. I do know that they have one or two in stock for " testing" so a call to him might clear it up for you. I think it's what I am going to try on this model.

[jrb]

The HiMaxx 6332-230 ( www.maxxprod.com ) is at the top of my list of motors – has anybody used one?

[jrb]

Have finalized my set-up; all big ticket items are on there way: two DeWalts via eBay & motor via EFM, one of local good guys. The RX, extensions, & long arms should be here soon too.

So here what the list on items not in the manual:
RX: JR R700
ESC: Kontronik 3SL40-14-32 (40amps & up to 32NiCd)
HV UBEC
Pack: A123-10S- two so fly either 1P or 2P
Motor: HC6332-230 from HiMaxx/Maxx Products
Prop: APCE 16x10

I extended the HiMaxx motor performance chart to my area of interest as shown below; have included their data sheet too.

Rather than more normal “loom” I’m thinking about adding a regular Sermos/Power Pole set of connectors to the fuse holder, all wired with 13ga.

This will let me go to 20amps for recharge via my Mastech 5020; my 1/5 Cub loom is limited to a 10amp recharge with the 16ga wire.

Don’t know when I’ll crack the box open; will likely be worked on through the TG/weekend – maybe fly 1st part of December – my Mustang was maidened in December!

[Geoff Dryer]

Below are some statisitics on the new AXI 5320/18 motor from their website (www.modelmotors.cz)

No. of Lipol, Properler, RPM, Volt [V], Curr [A], Power [W], Effic [%]
6s APC-E 16"x8" 6900 21,6 46 994 85
6s APC-E 16"x10" 6800 21,6 48 1037 85
6s APC-E 17"x10" 6600 21,6 56 1210 83
6s APC-E 18"x8" 6550 21,6 58,5 1264 83
6s APC-E 18"x10" 6350 21,6 69 1490 80
6s APC-E 18"x12" 6200 21,6 78 1685 77

I have Hyperion 6S 5000 packs (20C). Any opinions on this motor and battery combination on the 1/4 scale Cub?

[jrb]

Should be good, though that's more amps than I want to use to get the Watts.

Want to up the charge current capability of my normal “loom” (Mustang & 1/5 Cub shown above) for my – A123-10S2P. Need both a larger gage wire and charging receptacle good for 20amps

Like the wiring simplicity of the method shown below, and Considered using the Astro Flight 3 pin connector.

But then I’d need to make some sort of tab/flange so it could be mounted in the side of the fuselage.

Stared at some Sermos/Anderson Power Pole connectors and my box of parts and ame up with the following scheme:

1st step is to make some mounting tabs for the PP.

I found that a nylon clevis nicely fits inside the shell.

So I trimmed off the connection portion, and removed the metal tab; pushed in the clevis (had two w/busted pins!) and had a way to hold the connector set up to the side of a plane.

Next I added one addition shell to my normal battery type arrangement, and turned it 90.

The jumper is made by using some 10gage solid copper wire.

As you can see now I can jump/arm and charge from the same point of the plane. The wiring is the same as the AF description.


UBEC & Switch will be added as I normally do.


This doesn’t require the heavy duty soldering for the AF connectors.

If you crimp your PPs you only need solder the jumper.

[Ron]

Geof:
That's the setup I'm going to try in my Cub...
although some may think that the amp draw is somewhat high, in my experience with larger models, it doesn't take near as much to keep them in the air as you may think...my Venus 2 draws 70 amps static, but I get really good flight times on the Evo 3700 packs. this is almost 1400 watts...you would think that it is stressing the system, but when I land after a full pattern routine, the batteries and motor are barely warm. an intermediate routine draws only 1270 mah from the batteries.( about 6 minutes for me )
Before the lithium and outrunner were popular, we used to think that 65 watts to the pound was lots for spirited performance..as long as you have between 1/3 and 1/2 the models weight for thrust, it will work just fine.
after all...this IS a cub...not an aerobatic machine.
just my opinion of course, but it's worked for me for the past dozen or so years of flying electrics.

[Geoff Dryer]

Thanks for the note Ron

We all seem to be in the habit of overpowering aircraft. There is some very un-scale like Cubs in our club.

Are you planning on purchasing the Hangar-9 1/4 scale Cub?

[Ron]

Geoff:
It should be arriving the end of this week...I ordered it from the LHS here in town. He has been really good at getting things in, and his prices are great. I talked to John M about the new motor last night, and they have not had a chance to test it yet, so next time I'm in Langley, I will go by Richard's place to have a look, and see if I can
hornswaggle one out of him.

[Ron]

Anybody know off the top of their heads what diameter a full sized Cub propellor is??

Geoff.......It arrived today ....I will have to wait till tomorrow to pick it up though....BUMMER

[KOMET 44]

Hi Ron,I beleive full scale prop is 96".

KOMET44

[jrb]

71"x44"; so 1/4th is 17.75.

[jrb]

Made my 1st A123-10S1P pack!

Got my Dewalts earlier this week; took them to a DeWalt service center and got them fully charged/checked out on their system – both passed.

Picked up my motor Thursday, so have been planning out my activities for the weekend since then – Bach’ing it, wife took her mom to the family home up north.

1st major activity was to run up the motor; needed to: solder the leads on the pack, shrink wrap the pack (Batteries Plus was the source of the 6” ST), configure and mount the motor to my run up stand.

Also needed to open up the prop for the 12mm prop adapter; and find a big washer to use with the prop plate and nut as HiMaxx just like AXI (& others) didn’t put enough threads on it for use with APC “E” prop!

Then outside for the test!

My data with the 16x10 hit right on Hi Maxx’s chat: 31.5amp, 29.7volts, 936watts, & got 6180rpm – all close to the predicted too!

Next up plane out/install battery and cabling.

[jrb]

A bit more done.

Wired up and checked out my “loom”; installed it in the under the dash, should be able to get at it with the “doors” open.

Found it easiest for to install the loom and likely the servos to have the fuselage standing vertical; keep me from banging the tail into things – a lot less space on the work table.

Also, made the motor mount block extender; put in a few hole to make it lighter – probably will find out I could use the weight!

Going to set-up the servos and TX next; will use “sub trim” to center the servos.

[jrb]

Pretty successful weekend!

Got the TX/servos set up and the tail all rigged up.

Standing the thing on its nose for most all of the work has kept me from banging it around like a lot of other planes I’ve done.

Wanted to get the mains on; didn’t make it before Deb arrived home.

Got all the wing activities to do next.

3 things I don’t like doing; just me I guess: joining wings, gluing on stabs (V & H), and hinging!

Well only needed to do one of those; will hinge the ailerons soon.

[hermperez]

Have you done any preliminary balancing yet?

[jrb]

Not yet; haven't done a thing with the wings yet.

Form the other guys experince it seemed as though he didn't have a balance issue.

If needed I could get both packs where the tank normally goes.

[jrb]

Finished wings (only need to set throws); so I did my 1st balance – no more Swiss cheese!

Even added a ½” threaded hole on the bottom of the pipe so I can add a little more weight if needed.

Note: this is with 1 pack mounted where the tank would go; the 2nd will be the passenger!

Windows to glue in; will leave the top out till I have CG set; and may leave the port rear out for cooling – might do hole in bottom at some point.

Maybe a maiden next weekend, my wife says she’s excited to see it fly!

[Ron]

jrb....nice job...I especially like the " switch" you made...going to try one in mine too.

Are you happy with the way this model was built??? Mine looks to be very well executed. maybe not as light as some of us might think we can build ourselves, but not terribly heavy either.

[jrb]

Thanks Ron.

Its a very nice ARF; best I've ever done!

Weight seems good; definitley a long way from the past.

Laser cut sure has helped them too.

95% plus on things fitting together.

Only thing I can remember needing more than put it togther were the elevator control rods -- too long. Threaded them a bit more and cut of the extra.

Other nits: tail wheel doesn't go as far as the rudder (maybe the springs need to be tightened), the RX shelf didn't fit the shelf above it too, and the struts line up -- cut there very close.


I told my wife its the best I've ever had.

[Ron]

yes it's a long way from the old Rolls Canardly models we used to see.





( rolls down the runway, canardly fly)

[jrb]

Got into electric just as the post "RC" era was ending about 1999.

Here's my other conversions and some other models too.

[jrb]

Photos are from our Electric Club’s meeting on Monday ( www.marcee.org ); glued on windshield last night.

Will disable Aux2 switch (JR 9303), so I don’t get funny starting positions on Port Elevator!

[jrb]

Into the office @ 0630 out for the day @ 1130.

Several flights on the way home w/FreeStyle & 1/5th Cub – cold soaked A123s worked great! Plane spent last night outside in the car – in at 40F, low was 30, & near 40 for flying. Didn’t really notice any change in flight performance; but then a notch or two above normal wouldn’t be a big deal. 2nd flights just like always.

Got home and went to work on the Q Cub; main activity CG. Here you can see I did it w/o having the top window in so I could hang it from some nylon cord.

Needed just a little in the nose 1-1/2” bolt & ½” nut.

Also, checked for CG w/o wing; this weigh I can check it when I put on the skies or w/2nd pack – etc.

Ok weight:
Fuselage = 11# 4oz
Star Wing = 2# 2oz
Port = two two too!

Total RTF w/one pack = 15.5#; spec calls for 14.5 to 16.5 – right in the middle. Add another 1-10 for the 2nd pack to fly as A123-10S2P – maybe fatter than Gas?


Here’s how I store the wing panels:


Think about what I missed, etc. and then she’s ready to go!

[Ron]

looking good Jim.....it's a biggie isn't it? weight looks about right in there....
mine hopefully will be just a tad lighter from the smaller/lighter batteries..
and the motor weighs in at 10 ounces.
about 15 lbs est. wt.

[jrb]

Ron,

I went from the swiss cheese mount to solid, and also have a brass bushing on the prop.

Are you willing to mount you packs therough the firewall?

After all you packs and motpr are lighter than mine.

[Ron]

I was going to cut a slot in the firewall for the plywood tongue that sticks out from the front of the battery, but that was it...I guess final position will depend on CG.
I don't really want to add dead weight if I don't have to....ran into a minor hitch with the horizontal stab....seems the CF tube for the stab is splintered, and needs to be replaced....luckily I had to go into town on business this afternoon, and was able to pick up a new piece of CF tube. also am replacing the white plastic clevis fittings on the stays with metal ones...they're smaller in overall size, and are not so obvious.
More next time.

[jrb]

Ron,

Some photos I've collected of MaxCim mounting and having the pack span the firewall -- needed to do this on my 1/5th Cub.

I made the PCV thing when I had a MaxCim.

[Alan H. Siegel]

Which analog servos, Futaba or Hitec, do you fellows feel adequate for an airplane of this size with its large surfaces? I have to buy servos for a comparably sized plane and I suspect that I need more muscle than is provided by with the old Futaba 148s and S3001s I now have. Thanks.
Alan

[hermperez]

Alan, the old 148s and 3001s are fine.. this is a slow flying plane.

[Ron]

Herm's right...the servo requirements especially for electric models are not nearly what everyone thinks...I use HS225BB servos on most of my larger models....some of my 80" plus models have been known to fly with HS81's....since there's practically no vibration in an electric model, you can get away with a lot less in the servo department.

[jrb]

I went with everything called out for in the manual; figured it would be PnP – even bought the long servo horns & ferrite filters.

Have always found when using different servos sometime you need to do more work to get them installed and rigged right.

Still had to increase the length of the threads on the elevator rods and cut them by about ¾”.

My servo of choice has always been the Expert SL-451 – nicest feature is that you can “center” the servo via a pot with access down the hole for the control horn screw!

These days they are sold as JR Sport 48s.

Will be off to the field in several hours!

[taildragger1589]

Will be off to the field in several hours!
Hey jrb.
thought I'd stroll over from the conversion forum to see how the maiden went. (gonna post vids?)
Thanks again for the a123 advice. I had no idea what they were, but after some research I'm starting to like the idea of going with them even tho they're heavier. (30 oz. vrs 24 oz. for the 6s2p,) and leaving them in the plane.
Have you seen this place?
http://www.modelelectronicscorp.com/view_products.php?tid=1&stid=2
they seem to have fairly good prebuilt pack prices and a good looking charger for 123's.
Thought you might like to see a pic of the first 1/4 scale cub I built back in 1980. Had a sixty turning a 12 * 6 prop at 11k and weighed 11 lb. (it was a scale model of the '43 cub I was renting at the time for $8.00 an hour and had about 35 hours in it at the time.)

[jrb]

Success!

Two flights today; got the thumbs in shape with the FreeStyel, then a “little” Cub (1/5th) flying, finally on the bigger!

Take-off was easy, very nice climb out at just a couple notches above ½ Stick.

Needed just a few clicks of down; have to hold forward on the stick to fly fast above ½ throttle.

Pretty windy – looks like she nearly stopped up high power-off.

Straight stall, tight loops – nice Cub!

Might need a tad more weight in the nose?

Maybe I’ll play around with the CG when I put in the other pack?

Used 1500mah for the two flights of about 5 minutes; everything was nice and cool not even warm post flight.

Recharged the 10S1P pack in about 8minutes starting at 20+amps via the MasTech 5020 -- it pulls 900watts when set at 36.5volts & 20.9amps. Won’t quite get that from my 850W inverter.


Anybody interested in my 1/5th?


Very nice, what ever happeden to her?

I've gotten most of my A123s from Pete @ MEC; for this project I just used them straight from the DeWalt packs -- soldered on leads and put them in heat shrink.

[taildragger1589]

Success!
Congrats!!! :D
I guess once the cub bug bites, you're infected for life.

Very nice, what ever happeden to her?
Thanks, she died of "surely the battery has one more flight in it" Flew very scale tho, had to dive for about ten sec to do a loop. climbout was in a nearly level attitude. even had a working gas guage on it (wire on a cork).

I've gotten most of my A123s from Pete @ MEC; for this project I just used them straight from the DeWalt packs -- soldered on leads and put them in heat shrink.
If I can, I try to stick with prebuilts since I'm known around here as the king of the cold solder joint. :o

I love that charge/jumper plug on the panel, that's a real keeper of an idea. really beats having the two plugs hanging out the cowl.

Looks really good in the lineup too.

[jrb]

Four great flights today; off skies with the 2nd pack in parallel too.

Snow was great and air was good too; virtually no wind and dense since the air temp was about 10F.


Flights were about 12 minutes long and I recharged in about 12 minutes – how about that virtually 1minute of flight time for 1 minute of charge!

And, I didn’t spend ½ that time between flights and charges – 84 minutes of flying and charging and was only at the field 2 hours.

A123s are great!


Loops and rolls; even got in some inverted flying.

Neither the skis or the 2nd pack was a negative impact.

[karl k]

Any pics with the skis?

Did you make them or buy them from somewhere?

Karl

[jrb]

Skis are from here ( http://www.maidenusammp.com/ ), stocked @ my LHS.

Have just sold my 1/5th shown below haning in its storage rack with a set of "large"; now being used on my EQC.

Also, have the smaller size as used on my converted .40 American Flyer.

The large work very well on the EQC, except for deep powder where a bit bigger would better.

[Alan H. Siegel]

Hi,
I plan on using a 7S2P pack of A-123's with my Sr. Telemaster conversion. The only balancers I can find are limited to 6 cells. How do you handle balancing your 10S A-123 packs? Thanks.
Alan

[jrb]

No balancing required!

Well that's not entirely accurate; you need to start with a well balanced pack and then treat them reasonably well -- not too low and fast/slight over charge (i.e. I set my MasTech to 36.6V & do 20amps).

To get my pack well balanced I put them on a DeWalt charger before tearing them a part. Even got this done @ a DeWalt place so the would warrant my pack if it was bad!

I also didn't bust up the welded tabs on my packs since I'm doing 10S; and kept the stock stuff if balancing should be needed in the future.

So to do a balanace I could do a re-assemble, or sort of re-asseble and use a DeWalt charger.

Or use the end caps to do a single cell voltage charge -- 1S10P.

In addition to all the above, I could use my TP-1010C and 210V with balance taps.

[LBJ]

Got my fuselage going pretty good, almost done. No real hurry to get finished. I decided to put the servos between the seats for ease of access and better weight balance. The Rx is up below the instrument panel. I filled in the area where the gas tank would have been. I also changed the rear seat to a more scale appearance with some balsa and a little Dremel tool work. The pull-pull cable goes under the seat structure. With the front seat in, the whole servo area will probably not be noticed.
http://img.photobucket.com/albums/v228/numskin/Kitty624.jpg
http://img.photobucket.com/albums/v228/numskin/Kitty626.jpg
http://img.photobucket.com/albums/v228/numskin/Kitty628.jpg
http://img.photobucket.com/albums/v228/numskin/Kitty629.jpg

[jrb]

Link to some video of my Cub and other planes at my club -- 5 cylinder radial is way cool!

http://www.youtube.com/watch?v=ghoiS1h3o98

http://trivalleyflyers.10.forumer.com/viewtopic.php?t=9

[johnm15141]

I just bought one of these used and had a question about ESC's. I originally posted over here:

http://www.rcgroups.com/forums/showthread.php?t=912003

but perhaps it would more on topic to ask here?

Discussion - Hacker MASTER 90-O-Acro controller is a JETI?

I just bought a used Hanger 9 1/4 scale cub with a power 110 motor and servos installed. The manual calls for the Castle 85HV ESC. The seller must have needed it for somethig else but he included a brand new Hacker MASTER 90-O-Acro controller like this:

http://www.aeromicro.com/catalog/ha...0oa_5396477.htm

It looks very similar to the Advance PLUS 90 Amp Opto Brushless Motor
Controller at hobby-lobby: http://www.hobby-lobby.com/jetiblue.htm

Does anybody know if the Jeti programming card will work with the hacker? (I have the card for my Axi/Jeti's.)

Is the Hacker a descent ESC? I'm only familiar with the Castle line. Should I sell this ESC and buy the recommended Castle?

[jrb]

I just bought one of these used and had a question about ESC's. I originally posted over here:

http://www.rcgroups.com/forums/showthread.php?t=912003

but perhaps it would more on topic to ask here?


Might be best to ask in the Power System forum: http://www.rcgroups.com/power-systems-13/ .

[johnm15141]

I'm installing the electronics for a Power 110 with the Hacker ESC (Turns out its an outstanding ESC!) I'm using a Spektrum AR6200 powered by a Castle BEC. There's a switch harness under the back seat. The manual (for a GAS setup) says to plug the reciever and battery into it. I would like to use the switch under the seat in my electric conversion. Is anyone familiar with the switch layout? Can I plug the ESC and the BEC into it and plug the switch into the throttle port of my AR6200? Or should I use the switch to isolate the throttle lead from the ESC so that after my Lipos are plugged the Rx is powered but without throttle input?

[jrb]

My RX switch is between the BEC and the Pack!

Its alos mounted near my charging/arming point on the dash; versus under the seat.

Its a lot eaiser to get to!

here's some photos:

[johnm15141]

I can't ask for a better answer than that!

Thank you.

I'm also using powerpole conectors. After looking at your schematic I have decided I will also do both: use the seat switch on the Bec and make a powerpole arming key between the ESC and battery.

[johnm15141]

Whoops bad news! I followed the schematic, hooked everything up and went to bind my Rx. All went well, I powered down removed the bind plug and powered up. I couldn't get both elevators to work with my Spektrum DX6i. So I powered down and went to read the manual. Came back with some ideas, powered up and there was a loud pop. I fried my Castle 10Amp BEC. Crap! After I did that I looked at the specs and the "durn" thing is only rated to 6S. Its charred and I'm red faced! I should have looked at the specs but I assumed that BEC's where for this type of application. Time to start searching for a BEC that can handle 8S I guess...

PS I hope you don't tell me that "Everyone Knows you can't use BECs over 6S(Like this Castle BEC) then I feel even lower... :o )

[jrb]

Mine's a UBEC from Koolflight Systems: http://www.koolflightsystems.com/ .

[johnm15141]

As soon as I read your post I remembered that I had installed a Koolflight Ubec in one of my planes that had 6 Servos installed. I'm going to cut that out and install it in the Cub this afternoon.

Then I can get back to solving the real hard problem of finding the proper settings for the Hacker ESC to work with an E-flite Power 110 (the default ones don't work, I tried when I first hooked it up.)

My Plan is to fly it with two Evo 30 4S 4500mAh in series and a 17x10 APC prop. Once I get it working I will what this setup to make sure its safe and sufficient to fly the Cub.

I wish I had paid closer attention to the little details, I would have used swapped the BEC's instead of learning a $20 lesson about maximum input voltages on BEC's :p

[johnm15141]

Ok, I'm ready! I just watted it with my two Evo 30 4S 4500mAh in series and a 17x10 APC prop. It came out at 1350 Watts, 50 Amps, 28volts.

This works out to about 90-100 watts per pound. I believe I will get very nice performance with those numbers...

At 50 Amps, I think I can add another inch to my prop diameter. The Hacker opto-90 can handle 90 amps, so an 18x10 would be fine, maybe even a 19x10, which is the max recommended size for the Power 110.

I'm going to load it up tomorrow and head out to the field, winds are forecast at around 10 Mph. Perfect!!!


(Update: Actual Winds are over 20 Mph, probably gonna postpone.)

[johnm15141]

Update.

I've been out of town for awhile and haven't had a chance to maiden this plane yet. But, I did get my 19x10 prop. Todays winds where 25+ MPH, I think it can handle that but I'd rather first flight on a calm day.

I watt'd it with the new 19x10 prop using the following config:

E-Flite Power 110
APC 19X10E Prop
Hacker Opto 90 ESC
Spektrum AR7000
5 Hitec HS-422BB Servos
Flight Power EVO 30 4S 4500 mAH Lipos X2

This gives me an AUW of 15lbs 2ozs

I tested it on a Medusa Power Analyzer II from Hobby-Lobby (http://www.hobby-lobby.com/testequipment.htm)

The results where:
32 Volts unloaded
26 Volts Loaded
72 Amps
1940 Watts

That works out to 128.2 watts per pound and according to e-flite that is for advanced aerobatic and high-speed models from the following table that came in the manual to the motor:

• 50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
• 70-90 watts per pound; Trainer and slow flying scale models
• 90-110 watts per pound; Sport aerobatic and fast flying scale models
• 110-130 watts per pound; Advanced aerobatic and high-speed models
• 130-150 watts per pound; Lightly loaded 3D models and ducted fans
• 150-200+ watts per pound; Unlimited performance 3D models

Of course using the power consumption formula 4500mAh at 72 Amps gives me about 4 minutes of runtime at WOT. So I'm looking at about 8-10 minutes of endurance at normal throttle settings. When I do put this in the air someday (This sunday I hope!) I will set a 3 minute timer to measure the power consumption.

I spent this "windy" day marking the CG and setting the high and low rates per the manual. No mention of expo so I set 30 for the Elevator and Ailerons and 40 for the rudder in both high and low rates, which are keyed to the rudder switch on my Spektrum DX7.

I have one channel left over for a possible camera mount on this plane, but people are asking me if I can set it up as a tow plane for gliders, maybe I'll use that channel for a quick release....

[BARNESJONR]

Fly it over my way and I'll get some video and photos of it! It should be large enough that you'll still be able to see it from LVRC as it passes over NBRC! :p

Looking forward to your maiden John. I sure would like to get one of those 1/4 scale Cubs!

[johnm15141]

I finally got it in the air today. It flew superbly!

I cracked it open a quarter throttle to take it easy for the first flight. Instead it rolled 2 feet and was airborne. I also set it up with low and high rates but quickly abandon the low rates as unnecessary. It lands at a very slow speed. It flew so well it made me look like a good pilot, my secrets' safe with this plane!

I got six minutes on my battery setup of 8S-4500 mAh. As I learn better throttle management and the batteries break in, I think I can get it to 10 or more on this setup. I flew it each and every time the batteries where done charging, it was so much fun.

Only odd thing was it had a slight negative dihedral on the wing that I did not notice till it was airborne. I'll fix that along with the various dings and pokes the coating took. Its so big I've got to be doubly careful while transporting and storing it. Now, out to the garage to patch that tiny hole in the wing after that incident putting it in my car at the field :o (Oh yeah, and mow the lawn too, I promised...)

[BARNESJONR]

Sorry I missed the flight! I had intended to be there but when I first cracked an eye open this morning, the clock reported 8:17! I haven't slept in THAT late in a while! :D

[johnm15141]

Got in some more flights today. I'm still flying around 6 minutes. Each time I fly the batteries are less discharged, my last flight today had about 30% use-able charge remaining in the batteries. I'm getting better at throttle management and the batteries seem more efficient now that they have been cycled 5 or 6 times. My last fight also included a high altitude climb for the fun of it...a huge waste of energy, but fun!

I will change my timer to 7 minutes on my next outing.

Also, each time I transport it, I do something to the wings. I'm going to have to look seriously at a wing bag or something.

Anybody have any experience with these wingtotes from Horizon Hobby:

http://www.horizonhobby.com/Products/Default.aspx?ProdID=WGT101

[61ahs]

I have the 82" WingTote bag and it works very well to protect the wings during transport and storage. I made a double pocket sleeve thingie out of soft felt so that both wing halves can be put in the bag. The wings are inserted wingtip-to-wingtip and they overlap up to the strut mounts. The pocket thingie holds them in place and keeps the wings from touching. Kind of hard to describe, but it works great.

Rick

[johnm15141]

Thanks for the info! I'm going to start shopping for the WingTote.

I flew several times this weekend, and was able to move my timer to 7 minutes and still land with 30% charge remaining. I'm getting better at not using the throttle when not needed, and executing an acceptable takeoff and slow climbout. I can tell there's room for more improvement on my throttle management. My goal is to reach 10 minute flights on 8S-4500mAh.

I haven't been able to remove the negative dihedral from the wings, prior to each session I put one full turn in each strut and lock it down. Its getting better.

I'm amazed how quickly the cub assembles and dissembles in the field, most of my smaller airplanes are a real hassle removing the wings that I don't even bother. I've heard comments about how fast it was ready to go from when I pulled it out of the back of my car.

[johnm15141]

I found a perfectly suitable set of wing bags! $10 each, 60"x29" perfect!

I was at my local mega discount store and spotted some children's sleeping bags on sale for $10 each. The wings will fit perfect, and if I put velcro on the end where you stuff the kid in, it will seal them and they are plenty padded

:cool: course' all the other kids with 1/4 scale cubs will make fun of me for the Sponge Bob Squarepants wing bags but at least they'll be well protected :D

[BARNESJONR]

Heck. I'd pay extra for wing bags with Sponge Bob and Patrick on them! :p

BTW, thanks for giving me a turn at the sticks last weekend. That was SO cool, getting to fly a 1/4 scale Cub.

Are you brining it to the Funfly this weekend? I think my co-author and buddie in Stockton is coming over with his, so there could be a pair of them on site. A great opportunity for some Cub formation flying! :eek::D

[johnm15141]

I sure am!

Now I just gotta figure out how to get it and my kids into the car, I thinks it against the law to carry kids on the roof rack so I gotta come up with another idea....

[Bill Hawthorne]

Many...many...years ago (how about the mid 80's) knew a club member with a Balsa USA 1/4-scale J-3 Cub..all he owned was a small Ford wagon. He used to fasten the fuselage to the roof rack and stuff the wings in the back..got a lot of funny looks going down the road but always made the 25 mile trip to the club field without any trouble.

[BARNESJONR]

Two trips!? :p

My daughter will be THRILLED if there are other kids there. I told her there probably would be anyway.

[Geoff Dryer]

Can someone tell me the length and diameter of the wing strut pins (pin and keeper). I am thinking of using them for another project. They can be ordered as a separate part HAN4563. - Thanks

[CrashCaley]

First of all, I wish to posting on the thread started by the originator. I'e struggled to find a thread that relates to what I have.

Gentlemen, Thank you for this thread. It has given me a little more information as to how to convert my newly acquired 108" wingspan 1/4 scale Balsa USA J-3 Cub Kit. A friend surprised me with the gift yesterday, which had been given to him by one of his friends. My friend already has one, so he thought of me and my electric airplane craziness. This kit is probably 1/4 built already. The fuse seems to be nearly framed out, and one wing panel started.
My biggest problems are going to be choosing proper covering. I am just starting to learn how to cover with plastic type coverings. I had for my first few years just purchased BARF's and flown them. Only since I've been building free flight airplanes, have I attempted to build radio controlled ones also. So, if anyone has suggestions on what I should use for covering, I would appreciated your comments and suggestions.
This airframe with .90 sized 2-stroke glow engine is supposed to weigh in around 15-17 pounds. The fuse is 39 ounces as it is.
What would be a good electric motor system to use? I thought an E-Flite 110 outrunner might be ok, with a CC 85HV esc, and a six cell 5000mAh lipo pack. This is just a guess, and I really don't know if it is a good setup. I
will not do any kind of aerobatics with this airplane. I just want to takeoff, fly for about six minutes and land. Maybe do that twice in a flying day. Doesn't take much to make me happy. :)
As I said, I appreciate all your suggestions and comments. I am new to giant scale. I'm used to flying things less than half this size. I've been told that I will be very happy with this, as it is very easy to fly. I sure hope so. Caley

PS I've removed the cheek blocks from the nose section, as suggested by my friend. My friend provided me with an ABS cowling and fake motor stuff, as well as the landing wires and wheels

[jrb]

IIRC someone is flying the 1/4 H9 J-3 on 6S LiPo; if you keep the weight down you should be ok.

[CrashCaley]

JTB, You've got me thinking now. I believe I shouldn't worry about the power train until I get the airplane built with servos and receiver in it. Then, at least I will know the dry weight.
I guess the only valid question at this point is, what kind of covering should I use for an airplane this size? Will Monokote work, or should I use something like Coverite 21st Century Fabric? I really don't want to use silk or similar that needs doping and painting. I can't stand the smell of either very well. Caley

[steve1814]

JTB, You've got me thinking now. I believe I shouldn't worry about the power train until I get the airplane built with servos and receiver in it. Then, at least I will know the dry weight.
I guess the only valid question at this point is, what kind of covering should I use for an airplane this size? Will Monokote work, or should I use something like Coverite 21st Century Fabric? I really don't want to use silk or similar that needs doping and painting. I can't stand the smell of either very well. Caley

I really like WorldTex (solartex by another name) fabric as I find it easy to use, covers quite well, and comes in a ton of colors. I admit though, I have never tried 21st Century (like their iron though!) I know wholesale trains (http://www.wholesaletrains.com/Search2.asp?Search=world+tex&scale=%25&Submit2=++Search++) has the best price (that I have found) for it.

As far as getting your power train setup: It is a good idea to sort out what type of batteries you are going to use for the model and prepare the airframe to accept the type you want to use (i.e. hatches and trays). You also should consider how C/G is going to be affected. Normally the batteries wind up in the cowl area or just behind the firewall, so good egress to the batteries is a must. Whether you leave them in the airframe for charging (I'd only recommend that for A123's!), or take them out, there is nothing more frustrating that to have to disassemble the plane to get your batteries out -ask me how I know this:o

Hangar 9 recommends a Power 110 on 8 cells for their J-3, but I concur with JRB, you can get some great flights (scale) on 6s and a Power 65/90. Of course I power my 1/4 scale H9 SC with this (http://www.hobbycity.com/hobbycity/store/uh_viewitem.asp?idproduct=4572) :D.

Keep us posted on your build!

Cheers,
Steve

[CrashCaley]

Steve, I've never heard of Solartex. I will have to look into it.
Definitely a good idea to put the batteries in the cowling area. I'm not familiar with A123 batteries. I would have to research them to understand them.
I use Lipos exclusively. I never charge at the field, so that isn't a problem. The door on this model opens for access to the interior for bolting on the wings, so I would probably install the battery pack into the tray at home. Then just before putting on the wings and struts, connect the pack to the speed control.
I have to get used to an airplane this size. I've got a Pat Trittle designed
60" wingspan J-3 Cub, I scratch built from his kit that weighs in at 24 ounces AUW. The darn body of this weighs 39 ounces already. I just hope this big one flys nice and slow. I don't want to overpower it. Just want to have enough power to get out of trouble, and to fly scale like. Caley
Just noticed that link to United Hobbies. That definitely is a good price for the motor, and very close to what I estimated this puppy should have. I may have to get that. What speed control did you decide on?

[steve1814]

[QUOTE=CrashCaleyThat definitely is a good price for the motor, and very close to what I estimated this puppy should have. I may have to get that. What speed control did you decide on?[/QUOTE]

At the price for the ESC's I always get this one (http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4691&Product_Name=TURNIGY_Sentilon100A_HV_5-12S_BESC_%28Ver4%29) for anything larger than 5S. It works great with larger inrunners and A123's. Look up everydayflyer in the member list and read his A123 posts for info on this battery - I don't use anything else on models this size.

Cheers,
Steve

[CrashCaley]

It took me a while to figure out what the chemistry of A123 batteries are. I do have a charger that will charge 6 cells at a time. So, depending on the need for nose weight, I can choose between Lipolys and A123's.
I was hoping to fly this with just six cells, which means using that large motor you mentioned would be out the window. I found this at Hobby City
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7709
which might do the job. The Sentillion v4 speed control I happened to pick from their lineup. Looks very much like the Jeti Advance 90 OPTO. Wonder if one company makes both?
I guess that if I were going to fly with A123's, I would probably need two sets of 7 cells in order to have 4600mAh. The seventh cell I figure makes up for the loss of voltage from being .3 volts less powerful than a lipoly cell.
Caley

[jrb]

Note: 16xNiXx = 5S-LiPo = 6S-A123 -- I've got four 40/50 sized planes flying on A123-6S! (FreeStyle, P-51, AT-6, & SD-50)

My H9 Qtr Cub is A123-10S2P; older 1/5th (80") on A123-5S2P -- both do near 20minutes.

YMMV; but, w/A123s I'd stick to 10S and a low Kv motor!

Lower amps, near mid 30s will let you fly nicely on 1P, or longer on 2P; my 2P pack sits like a passenger! Maiden was on 1P.

[CrashCaley]

Thanks for your help and suggestions. I've done a cost analysis, and have come to the conclusion that I cannot afford to do this electric conversion. Just don't have the funds to do it. If nothing else, it will be a great conversation piece. I've already had a comment about it being a viable lumber yard. :eek: Really wish I could afford to do this, but it just isn't feasible. Again. thanks for all the leads and help. Caley :(

[Alan H. Siegel]

21st Century fabric is beautiful to look at and would be my choice if the wing structure is sufficiently strong so as not to rely on the covering for strength...it provides little or no tortional strength. For strength I'd go with the Monocote. Doped surfaces, which you can't use, shrink and provide structural strength...not so 21st Century fabric. This is the voice of experience speaking :-).
Alan

[CrashCaley]

Alan, Thank you for bringing that up to me. I will forget about 21st Century fabric. I guess the others like Solotex are much the same.
I am not sure how strong this models structure is. Wonder if anyone here has built a 1/4 scale Balsa USA J-3 Cub? Would like to know. I definitely don't want this thing falling from the sky because covering failed.
I would have thought that Monokote would be the worst to use, but then I have little experience with plastic covering. I've only covered three models, and it has been a chore learning how. Found that it takes tons of patience.
I am beginning to think that real fabric covering is the only best way to cover an airplane of this size, which of course, entails using nitrate dope.
Alan, what do you truly recommend I use for this airplane. Forget that I said I hate dope and paint. I guess I would have to learn how. Are there tutorials or threads concerning your favoured method of covering?
I really wish to do the covering right on this. The kit is a gift, and I wish to make sure it looks really nice to show John.
The instructions recommend at least 80 ounces of torque for the control surface servos. Would getting something much stronger be fine? There are some very strong digital ball bearing servos over at United Hobbies that looks almost like Hitec clones.
I would appreciate suggestions on servos, as they are the first item I am going to purchase. Those have to go in before I can cover the structure. I would prefer to build and install those as I do so. Easier than trying to reach around and through things.
My apologies for being a pain. I am just not experienced in these super sized airplanes. This is so big I could fly a small dog in it. :p Caley

[CrashCaley]

Guys, Thanks for your help, but I had to decide that going electric cannot be done on my budget. I am going to put in a 23cc gas engine, which will be a first for me. I like the sound of a gas engine though. And it is a little cleaner than glow. Again, thanks for your help. Caley

[Alan H. Siegel]

I do have, what I think is a solution for you. Cover the plane with Sig Koverall which is a heat shrinkable fabric and paint it with exterior latex paint which your paint dealer can mix to a perfect Cub Yellow. I used this on my Sr. Telemaster and it worked out very well. I built my Telemaster many years before I painted it and I had applied a few coats of nitrate. I suspect that you could do without the nitrate but I'd run a test first. Roy vaillencourt pioneered the use of latex. He has a paper on the process on his site. Google, "Vailly Aviation." Also Google "Sig Koverall" to learn its application and proprties. I know it is very strong and easy to apply. It does not have a coating so you have to paint the frame with Sig Stix-it before ironing it on but that is not difficult. I'm attaching a few pictures of my latexed Telemaster,

[jrb]

Found some flight video of my Cub; posted it here: http://www.rcgroups.com/forums/showthread.php?t=1004650 .

[jrb]

Wind was 10ish and it was pretty cold (15F) -- smacked you on the left side of the kisser; hand were warm though!

Snow was a bit soft so you didn’t want to be on it too long – take-off ski marks were 20 to 25 feet. Landing was 25 to 30.

[jrb]

Need just a hub for my Cub (inside); H9 list a whole wheel set :( ?