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Author Topic: Half A Airforce  (Read 2293 times)

Offline Pat Johnston

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Half A Airforce
« on: April 29, 2023, 12:44:39 PM »
There were questions about good electric 1/2A setups.  I've been messing with electric 1/2A size setups for a while.  It started with the Shark 202 and a Turnigy 2730-1500 motor with a 850/3S battery.  This worked very well. and made me think about a B17 with four of these.  The result was successful and resulted in a 595 square inch, 46 ounce machine on 63" .015" lines able to do the full pattern.  The motors were the Turnigy 2730-1300 powered with a TP 2800/4S battery.  This lead me to the Twin Epiphany 327 with a couple of Race Star 2730 1300kv motors.  At 25 ounces, the performance is quite nice.  The battery is an Ovonic 1500/4S.  plenty of surplus capacity.  Lines are .012" X 55". All three of these planes use the APC 6-4E props.  Tractor blades on the right side, Pusher on the left side.  On the twin and quad, the GP factors are eliminated, so that is a cool trick for multi engine designs.
In the single motor 1/2A size designs, I also have the Magician, and Ringmaster along with an Epiphany.  All are close to 200 squares, which seems good for this size of motor, especially when coupled with my "+P" airfoil.
I thought it would be fun to show what is available in the 1/2A electric world.
Pat Johnston
1/2A Design Division
Idaho Skunk Works


Offline Tim Wescott

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Re: Half A Airforce
« Reply #1 on: April 29, 2023, 01:42:52 PM »
Kewl.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Steve Berry

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Re: Half A Airforce
« Reply #2 on: April 29, 2023, 05:28:52 PM »
Very cool, indeed.

Have anything along the lines of an electric 1/2A Patternmaster or Cardinal Evo40, or really any of the Urtknowski designs? I'm thinking scaled to about 250 squares should be about right.

I'm sort of tinkering around with scaling down the Cardinal Evolution 40 to about 250 squares to see how it would look. But that would just be a straight scaling, not adjusting any moments.

Steve

Offline Walter Hicks

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Re: Half A Airforce
« Reply #3 on: April 29, 2023, 11:01:43 PM »
Pat, What kind of a bribe would it take for you to bring the B-17 to the regionals with you?

Offline kenneth cook

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Re: Half A Airforce
« Reply #4 on: April 30, 2023, 05:04:03 AM »
           Last season, I lost my C-47 which I built 40+ years ago. It was nothing special in terms of maneuverability.  I've currently built a Sterling P-38 to replace it. Pat, I would love to build your B-17 in a glow version if you offer such a model.

Offline 944_Jim

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Re: Half A Airforce
« Reply #5 on: April 30, 2023, 07:07:52 AM »
Mr. Johnson,

Your thread nails the size-plane I prefer right on the head! Especially the multi-motor stuff. Couple this with a zero-nitro finish option makes E-power very appealing to me.

I see no timer/speed controller mentioned, nor how to gang-control the motors on the multis. Can you provide those details please?

How do you handle multiple flights during a given flying session?
Do you switch pre-charged batteries into place? Or by fast-charging between flights, or a combination of both (fly one battery, charge one battery...or fly one plane while charging the other(s))? If you do charge at the field, how do you handle that?

Thanks much.

Offline Pat Johnston

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Re: Half A Airforce
« Reply #6 on: May 01, 2023, 08:59:31 AM »
I can supply plans or even make up a kit if so desired for anything you want. Mail me at patsplans@yahoo.com.
The controls are fairly simple the battery is in the nose and powers all four esc’s each mounted on the nacelles. Four FM9 timers are mounted on the nacelles and the starting delay is set at one second apart. To start the engines, you simply hit the timer buttons starting with the leftmost motor and in one second intervals progress to the right. This makes managing the startup very easy. The power of the four engines feels equivalent to an LA46.
The Epiphany 327 Twin was so amazing that I ended up designing an Epiphany 557 Twin by simply installing a couple Cobra 2808’s in nacelles. Two 9-6 props collectively power it adequately to say the least. All up weight is 47 ounces, which is an ounce more than the single engine version. 63’ .015” lines. We have several Twins flying from CA to back East. The advent of electric power has made multi engine plane’s very easy and reliably fun. Another bonus is the opposite rotating props. Say “bu-by” to GP.
Pat

Offline Mike Scholtes

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Re: Half A Airforce
« Reply #7 on: May 03, 2023, 11:23:15 AM »
Here's what Pat's Epiphany 557 Twin looks like. Will Hubin makes a timer for it that runs both motors, rather than using multiple timers. Shameless plug, this is an excellent kit with very good wood supplied by Pat and perfect fit of laser cut parts. Waiting for our NorCal weather to return to sanity before first flights.

Offline 944_Jim

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Re: Half A Airforce
« Reply #8 on: May 03, 2023, 04:19:43 PM »
Hubba hubba hubba, Mr. Mike! I think I've just been pushed towards E-power. Does the Hubi timer also include a retractable landing gear control? I guess I need to revisit that thread.

Mr. Pat, I'll add you to my vendors list. I may not buy now, but I will be in the market some time for a full bodied twin between 32"-38". Do you re-engineer/cut on the fly, or do you have a catalog?
My Hobby Closet can't realistically support much bigger, nor can the trunk of my car.

I'm still watching for how to handle back-to-back flights.

Thanks for letting me piggy-back/expand my horizons based on y'all's experiences.

Offline Mike Scholtes

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Re: Half A Airforce
« Reply #9 on: May 03, 2023, 04:59:06 PM »
I believe the Hubin timer can be ordered with a retract function. However on a model this size, or the much smaller ones you mention being interested in, that would add a lot of weight and complexity. But it does up the "cool" factor. Pat offers a full-fuselage and full-nacelle version of the 557 Twin, as well as many of his stunt designs. The full fuse version came out after I had started building this one (profile fuse and nacelles) and had it been available, I would have built that instead. Whatever, its an excellent kit and I can highly recommend it.

Offline Fred Cronenwett

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Re: Half A Airforce
« Reply #10 on: May 04, 2023, 10:34:39 AM »
Where did you put the battery on the B-17? Do you have one battery for all four motors? What is the span of the B-17?
Fred Cronenwett
AMA CLSCALE7 - CL Scale
Model Aviation CL Scale columnist

Offline Fred Cronenwett

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Re: Half A Airforce
« Reply #11 on: May 04, 2023, 10:36:23 AM »
Replace the timer with a 2.4Ghz reciever and you could fly with throttle control!

Fred
Fred Cronenwett
AMA CLSCALE7 - CL Scale
Model Aviation CL Scale columnist

Offline Pat Johnston

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Re: Half A Airforce
« Reply #12 on: May 04, 2023, 12:54:22 PM »
Jim,
Send me a regular email and I’ll send you the plans list. patsplans@yahoo. com.
Fred,
B17 span is 64”. 595 squares. The battery is in the nose, loaded in the left side so it is not noticeable from the outside of the circle. It is a TP 2800/4S. It runs all four motors with wiring through a ductwork in the front of the wing airfoil. Works very easily with four Hubin timers.
Pat Johnston
Idaho Skunk Works

Offline Fred Cronenwett

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Re: Half A Airforce
« Reply #13 on: May 04, 2023, 02:17:14 PM »
I did the math to size up a B-29 and came up with similar span.

Fred
Fred Cronenwett
AMA CLSCALE7 - CL Scale
Model Aviation CL Scale columnist

Offline Pat Johnston

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Re: Half A Airforce
« Reply #14 on: May 04, 2023, 07:50:33 PM »
Problem with a 64” B29 is the aspect ratio is kind of high compared to a B17.  Your wing area is likely be reduced to under 500 squares, demanding an under 40 ounces flying weight. Just a little more difficult. Of course, I have a tendency to think in terms of stunt performance. Word to the wise. Consider stretching the nacelles a little to reduce nose weight demands. My B17 is carrying 4 ounces of lead in the nose. The next one would have some changes a little away from scale, but not enough to be noticeable other than with a ruler.
Pat


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