My new 1/2A electric stunter

[Keith Renecle]

Hi All,
I've been trying to make a small stunter like a Babe Bee size for some time with an electric system that did not look like a "plumber's nightmare"! I also wanted nothing bigger than a 6" prop because of the ground clearance story. I therefore built a quick test model with a foam wing covered with tissue and white glue. I initially started designing a .15 size version and called it "Sparky"......with no reference to our web host!  Seeing that I scaled it down I called it the Baby Sparky. The nose holds the timer and esc very neatly with strips of Velcro that go right through and hold both parts. The battery is in the bottom of the outboard wing. I wanted it to fly for a similar time to a long tank Cox .049 that runs for around 3,5 minutes and I worked out that a 450 mAh 2-cell lipo should be fine.

The first motor I used is the one in the photo's and that is an E-Max GT2205/22 with a 1660 Kv. It did not work out well with the APC 6 x 5.5 e-prop with a maximum rpm of around 9300, so I tried my older Techone C-20 motor with a 2050 Kv and this gave me 10300 rpm on the same prop. I tested this yesterday in some strong wind that was blowing at around 16 mph or so, and it flew very well with nice loops either way and good inverted flight as well. After a 3 minute test flight my Hyperion battery checker showed that 31% of the charge was still left in the battery, so I guess I could fly even longer. Mmmm......I was happy with 3 minutes......I was rather dizzy from the short lines. I flew it on 10 metres (32.8 ft.) of 10 lb. Spiderwire. The performance was really good so I guess that I could push up the line length to 40 or 42 ft.

I would say that I've achieved my goal and the small Sparky is nice to fly. The foam wing with the medium tissue and glue is a bit heavy, so it could be made lighter with a conventional ribbed wing and light plastic covering. Overall though I'm happy with the project. Now for the .15 size model!

Keith R

[Horby]

Looks like a cool project, I was toying with making an electric 1/2 A pathfinder myself.


Warren

[Keith Renecle]

Hi Warren,
The 1/2A Pathfinder is a nice model and a little bigger as well. Dennis Adamisin did one for the Brodak stuff so the system is listed on this forum. My Sparky's wingspan is 24" and t weighs 174 grams or 6.14 oz. with the 2s 450 mAh lipo. I've added a few pics below to show how I mounted my Compact timer. You can see in the photo without the plug in switch, how the Velcro hold the time in place, then the switch simply pushes on and is easy to remove if you need any programming changes.

At first I thought that maybe a governor system is an overkill for such a small model, but it works so well and of course the shut-down feature is an added bonus when it gets pranged or when someone gets a finger in the prop. Even these tiny motors can inflict quite a lot of damage and if kids fly these models this is bound to happen sometime. I can remember this problem when I was a kid (well..........a smaller one) when playing with the Babe Bee engines.

The photo of the bare fuselage shows how I made the nose to hold everything. I use 1/6" ply and the slots are for the Velcro. The square hole lightens it up and allows for the wires between the esc and timer. I actually like these flat motors so I need to source one like that with a higher Kv. They look like a 12 cylinder radial engine to me so maybe I'll do a small Yak or something!

Keith R

[Crist Rigotti]

Looks nice Keith.

[Keith Renecle]

Thanks Christ, it was really a fun project so far, and I hope that the .15 size works out as well.

[Theo Kleynhans]

I was with Keith when he tested the plane, and I must say it flies really nice. Even with the strong wind, it looked easy.

Great plane Keith!

Hope to see the 15 size soon.

Theo

[John Rist]

Will they be kitted?

[eric rule]

Keith, you obviously have way too much time on your hands. You should have been working on KR Governor improvements like making the RPM decrease when the motor goes downhill or creating something that gives out the engine sound for those traditional modelers who insist on noise when they fly instead of wasting your time creating superior performing control line models (LOL) Next thing we know you will be competing at the World Championships (Oops, you've already done that haven't you?).

In all seriousness, Keith, the 1/2A looks like a great model. Good Job my friend!!!!

[Keith Renecle]

Hi Eric,

Yup......way too much time! Now......if RSM would just get some Black Tiger BT 2206C 1900 Kv motors, then I would not have to battle to find the right motor!  (is this a subtle hint or what??) Just by the way, my .15 size model will be using the BT 3530C motor as this looks perfect for the job. This is what I'm playing with right now. The tiny models are fun but are more difficult to fly than a .15 size stunter. Theo was there on Saturday, like he said and he also flew the Baby Sparky in the wind and managed very well. The strong wind was a good test and I look forward to flying it in good conditions.......one day when the wind stops out here in Darkest Africa!

Keith R

[Tim Wescott]

Keith, you obviously have way too much time on your hands. You should have been working on KR Governor improvements like making the RPM decrease when the motor goes downhill ...

If I'm not mistaken about the chip market, he'd have to learn how to solder surface-mount parts -- and not ones in the easy packages, either.

[Horby]

Hi Eric,

Yup......way too much time! Now......if RSM would just get some Black Tiger BT 2206C 1900 Kv motors, then I would not have to battle to find the right motor!  (is this a subtle hint or what??) Just by the way, my .15 size model will be using the BT 3530C motor as this looks perfect for the job. This is what I'm playing with right now. The tiny models are fun but are more difficult to fly than a .15 size stunter. Theo was there on Saturday, like he said and he also flew the Baby Sparky in the wind and managed very well. The strong wind was a good test and I look forward to flying it in good conditions.......one day when the wind stops out here in Darkest Africa!

Keith R

Just be thankful that you don't get the wind and weather we get here in the Calgary area. We fly in gusty 15 kmh regularly because if we don't we won't fly at all. Good work with the new plane. :-)

Warren