Author Topic: Li'l Hacker II Electric (CoreHouse) (Read 4181 times)

Richard Lewis · « **on:** May 27, 2010, 06:54:46 PM »

I am currently experimenting with a low cost E setup for 1/2A aerobatic use for mt 12 year old son to fly at the partk when we can't get to a big circle. The plane I'm experimenting with is a Li'l Hacker II, a 1/2A combat wing from CoreHouse. The plane is built pretty much stock, I added a 1" spacer behind the motor to get it further forward to get the CG more right. I also cut the tips off the wings to get it down to ~180 sq. inches after the first flight. I did a bit of research and bought the following to items to start with. Overall cost flying is about $35. With additional cost if you buy more batteries, charger, etc...

1400 Kv Outrunner Motor, $9:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=4204
10A Esc, $9:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=51432
2-Cell, 360 Mah Battery, $5:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7301
3 Cell, 360 Mah Battery, $7:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7302

Timer is the E-Flite one for $10

Flew for the first time yesterday with a GWS 8x4.3 slow-flyer prop ($0.50).

With the 2 cell battery, perfromance was lacking, just barely enough speed to stay out on the lines and zero aerobatic potential. The AUW with this battery is 7 oz. The Li'l Hacker wingtips were cutoff to give the wing area about 180 sq. in and it perfromed a little better than stock with 220+ sq. in., but still not viable for aerobatics.

With the 3 cell battery it weighs 7.2 oz and it could loop on the downwind side, but was still pretty anemic.

The amps for the 2-cell were about 5 amps and the 3-cell was around 6 amps. I used about 60Mah per minute on the 2-cell, meaning I could fly as much as 3 minute on the 360 packs. On the 3-cell, I used about 110Mah, meaning a two minute flight is about as much as I could get.

This tells me I have a little more power available in both the motor/ESC/Battery combos if I can find the righgt prop. I am going to try a APC 6x5.5e prop next and see if it gets the pitch speed up a bit, since the 8x4.3 prop had plenty of thrust, but did not cary enough speed/energy to stay out on the lines like it should.

The general goal of my setup was to be a light as a 1/2 glow setup (6-7 oz) and have moderatley aerobatic performance. If I concede a bit of weight and go to 9 or 10 oz, then it opens up a much wider range of motor/battery combinations that will give much better performance. Using a bigger battery 450 to 800 mah, allows pulling 10+ amps from the batteries, and allows the use of a more powerful motor. You end up in the $50 to $60 range...

An Alternate Motor with similar characteristics that seems better (lighter/more power) than the one I bought is:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6547

I'll try to post back with some more results when I have them...I plan to build the second plane from the double kit with few mods to lighten it up abit.

Regards,
Richard Lewis

Richard Lewis · « **Reply #1 on:** May 27, 2010, 07:02:29 PM »

We flew it again tonight...

I could not find a 6x5.5 at the LHS, but I found a 5.25x6.25...

On 3S, the pitch speed was plenty and the static thrust was low enough to need a good, firm hand launch. The amp draw was less than the 8x4.3 GWS, and once it was up to flying speed, it could easily do a wingover and loop from level flight. Neither me or my boy can do outsides or even lazy eights, so I'm not sure how it would do at them. With the amp draw being lower, the motor and batteries were very cool, so I know I'm not getting as much KW out of the motor/battery as I can...

On 2S, the pitch speed was OK to make straight and level laps once it got up to speed, but no aerobatics and needed a pretty hefty hand launch due to low static thrust.

Overall, I think the 6x5.5 is gonna be the one. I found a 7x5 pusher at the LHS and I may try reversing the motor to try it, but I suspect it will be too much load.

Last flight we pranged it and bent the motor shaft, so I will have to install my other motor (@ $9 I bought 2) before we fly it again.

Richard

Dean Pappas · « **Reply #2 on:** May 27, 2010, 08:12:31 PM »

That's right, Richard,
more pitch and/or more diameter means more power, right up until parts get too warm!
keep at it and don't be surprised if that 7X5 doesn't fly just fine.
Dean

Dennis Adamisin · « **Reply #3 on:** May 27, 2010, 08:31:36 PM »

You are off & running on the right track. Dont be afraid to try the 7x5. WIth 1400 kv I think you will have a har time getting enough RPM with 2S, stick with the 3S.

You moght also try the Brodak 2205 motor & 6x5.5 prop (they have them both) becauses it is a higher kv and should work well with 2S

Richard Lewis · « **Reply #4 on:** May 28, 2010, 08:42:31 AM »

Thanks for the encouragement, I think I'll run the 7x5 pusher next and report back on the results on both 3S and 2S....

I think you are right about the 2S setup...it will likely never produce enough pitch speed to fly a 7 oz draggy airframe with authority....higher KV might help.

Although I think I will still pursue a prop that loads the 2S setup to the max (~7A on the 360ma cells) and has enough pitch get the speed where it needs to be. Maybe I'll get another 5.25x6.25 and cobble up a 4 blade and see what happens. With the high pitch, the speed was adequate once in the air, but the static thrust was very low, making hand launches and basic aerobatics impossible.

Richard

CircuitFlyer · « **Reply #5 on:** May 28, 2010, 04:19:54 PM »

Richard,

Going back to physics class - It takes a certain amount of power to fly an airplane the way you would like. In the old days, most small 1/2a planes used the ubiquitous Cox reed valve motor. The power output of a reedie is about 55-65 watts. Electrically: Power (watts input) = amps x volts. If you load up your 2S setup to 7A then your input power would be: 7A x 7.4v = 52 watts. Our small electric motors are about 75% efficient, so your 52 watts in becomes only 39 watts output power at the prop. Probably not enough power to get the flight performance you would like. At 2S, you need more power (higher amps), a different prop isn't going to help.

Now at 3S, as Dennis suggests, load up the motor with a 7 inch prop to about 6A. Now your input power is: 6A x 11.1v = 67 watts. This will result in an output power of about 50 watts at the prop. Now your in the range of decent flight performance.

I hope I didn't lose you. There's a lot of helpful posts around the site. Try this one - http://stunthanger.com/smf/index.php?topic=16993.0

Richard Lewis · « **Reply #6 on:** May 28, 2010, 09:48:48 PM »

You didn't lose me...I'm an EE by trade.....I have never had known the approximate equivalent watts for the trusty reed setups, so it really is a helpful post for me....Thanks

Richard

John Cralley · « **Reply #7 on:** May 29, 2010, 08:04:07 AM »

Step up to a Turnigy 2822 1400KV motor $12.35 with an APC thin electric 7/5 pusher prop.
https://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=4915

The minimum weight gain with the extra power (use the 3S battery) should give you the performance you want.

If you want more than a 2 minute flight go to a Rhino 3S 460 battery ($6.39).
https://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=7304

My 2 cents.

Richard Lewis · « **Reply #8 on:** June 06, 2010, 09:19:19 PM »

Flew the 7x5 Pusher today...Seems like a good combo on the 3S. Still a bit anemic on the 2S, but flyable....I took apart the 5 2S packs I had and made 3 3S packs out of them...now I have 5 3S packs....

I'm thinking of trying the 7x6E tractor since I have about one more amp I can get...we're pulling 6A and taking out 200 mah in 2 minute...since I won;t get 3 min out of the 350 packs, I'm thinking if I can get to 7A (20C) that the mah usage in 2 mins should be just about max out on the packs....

Next iteration will be the 460mah or better packs, 3S and the 2822/1400kv motor. Although the motor I have is the same weight and theoretically the same power and seems to handle the 3S with no trouble (even thought it isn't officially rated for 3S), from what I've read, the 2822 is a better motor and I would have bought it initially if I had done a little more research....

Richard

John Cralley · « **Reply #9 on:** June 06, 2010, 09:30:28 PM »

Richard,

Sounds like you are headed in the right direction with the 2822 1400KV and a 3S 360 (or larger) battery.

Keep us posted on how this is evolving.

Tight lines!!!

ChrisSarnowski · « **Reply #10 on:** July 16, 2010, 06:15:22 AM »

Hi Richard,

Any news on the Lil Hacker? I think I will be giving mine a test flight this weekend assuming I work out the battery mount.

I am using a Turnigy 2822A motor 1650kv, Turnigy plush 10a ESC, Will Hubin timer fm0c.

I didn't think the 2s460 Rhino Lipo was going to give me enough punch, so I am going with 3s500 Blue Lipo. I have weight concerns, though, so I might try the 2s anyway.

I tried to drop some weight by cutting a few circles in the wings using a heated can (before covering).

-Chris

john vlna · « **Reply #11 on:** July 17, 2010, 01:48:08 PM »

Take a look at the alpha 300-1380 from hobbypartz.com It usually sells for about $11 and they are in the USA. I've used it on 1/2A's with success. It seems to like a 6x5.5 apc, draws about 10amps on 3s.

Richard Lewis · « **Reply #12 on:** July 19, 2010, 11:50:05 AM »

Sorry, no real updates...we've only flown a couple of times since my last post...all seems pretty good with the 3S packs, 1400kv motor, and the 7x5 pusher....

Richard

ChrisSarnowski · « **Reply #13 on:** July 21, 2010, 09:04:22 PM »

Thanks John for the suggestion on the hobbypartz motor...got my 3s500 from them.
Winds still conspiring against my test flights..

-Chris

Phillip Kenney · « **Reply #14 on:** June 21, 2015, 11:59:42 AM »

Coming late to the discussion so I may or may not get and answer but I'll give it a try.
It appears that the $10 E-flite time that you mentioned in the first post has been discontinued. Is there a recommended substitute that is in the same ball park price? Or a link to the flite one that is still in stock somewhere?

John Cralley · « **Reply #15 on:** June 21, 2015, 01:27:04 PM »

Contact Will Hubin. He has inexpensive timers that should do the job for you. whubin@kent.edu

Keith Renecle · « **Reply #16 on:** June 23, 2015, 11:07:20 AM »

Hi Richard,

My 1/2A Sparky flies great on a 2 cell 450 lipo with a 1900~2000 Kv motor and an APC 6 x 5.5 E prop. have a look at my thread and see if it helps a bit.

http://stunthanger.com/smf/index.php/topic,37540.0.html

Keith R

Duke.Johnson · « **Reply #17 on:** June 24, 2015, 09:07:30 AM »

Got Pictures?

Keith Renecle · « **Reply #18 on:** June 25, 2015, 12:01:53 AM »

Hi Duke,
There are pics in that thread. If you need any more info then let me know.

Keith R

Duke.Johnson · « **Reply #19 on:** June 25, 2015, 07:44:01 AM »

Sorry Keith, I wondered about pictures of the e-hackers. I have a couple hackers built for cox engines and we didn't like them that well. They belong to my oldest son and he was going to toss them, but I saved them for such an e-conversion.

Keith Renecle · « **Reply #20 on:** June 26, 2015, 09:44:33 AM »

No problem......sorry I misunderstood!

Duke.Johnson · « **Reply #21 on:** June 26, 2015, 10:23:41 AM »

No, I just wasn't very clear, I can't believe you don't read minds.

Author Topic: Li'l Hacker II Electric (CoreHouse) (Read 4181 times)

ChrisSarnowski

ChrisSarnowski