boingk's blog archive for May, 2011 - RC Groups
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Archive for May, 2011
Posted by boingk | May 31, 2011 @ 12:27 AM | 12,398 Views
Seeing as I had some foam left over from the sheet I bought for the F-15, I decided to use it for a small YF-22 Raptor. Its made from the plans at but scaled down to 75%. This makes it only 460mm wide and 720mm long when finished, using a very small amount of foamboard. Cheif worry was what electronics to use in it...

Its powered by a HobbyKing 'Fixed Wing' 20A ESC and OrangeRx 2.4ghx 6ch receiver. HK-15168 servos are used for ailerons and elevator. The power comes from a 600 to 1000mAh 3-cell lipoly, giving more than enough power for the Hextronik 3000kv 24g outrunner to turn its APC 4.75x4.75 prop. Seriously, this thing hoots along!

The linkages themselves are made out of an interesting combination of bamboo skewers, .020" music wire and heatshrink, secured with a few drops of thin CA. They seem to have held up well, despite high roll rates and fast turns at speed. The HobbyKing brand servos also seem to work very well - despite their price - with no flutter or singing and good responsiveness.

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Posted by boingk | May 24, 2011 @ 10:52 PM | 10,929 Views
So, the F-15 I built the other day? Here it is:

I finished it off with bamboo-skewer control links and painted it grey, then drew on some simple insignia to mirror the RAAF painting of F/A-18 Hornets... because Australia doesn't actually have any F-15's. Mechanical trim is neutral all round except for a small amount of 'up' elevator.

Anyway, I got to the field and threw it up into the air on about half throttle. It went very well, climbed straight up with only a minor roll to the left. I fixed that with some controller trim for right aileron and got about flying. It seemed to be very maneuverable and have great presence on the air, but top speed isn't exactly shattering - about 45mph. A broken motor mount forced me to dead-stick it down, which it seemed to do just fine.

A quick repair and I was back up... this time experimenting with props on the little 1700kv Blue Wonder / 3s 25C 1000 combo. I was using a GWS 8x6 cut down to a 6x6, and that seemed the pick of the lot for both thrust and speed. APC 6x4 & 4.75x4.75 were tried and both were average.

Today I plan to swap out the 1700kv for a 3000kv Blue Wonder motor and prop with a 5x3 before trying a 4.75x4.75.

Lastly, heres the Blue Wonder Bipe that I've been bantering on about:

Its not exactly a biplane anymore after its maiden incident, but with the lower wing strengthened with a 2mm carbon rod it certainly handles well enough now. Loops, stall turns... all snappy and tight. It'll be donating its 3000kv motor to the F-15, taking the 1700kv unit in its place. I'll most likely fit a 7x4 on this for some 3D capability.

Stay tuned for more as it happens.

Cheers - boingk
Posted by boingk | May 23, 2011 @ 03:51 AM | 11,224 Views
As the title implies, my latest efforts have been in the foamie direction.

The Blue Wonder Bipe got a transformation into a monoplane with full-house 4ch control. It flew very erratically until I aligned the thrust and trimmed correctly, but now is a nice plane to fly. Despite its flat airfoil it will happily romp around the skies on part throttle and thanks to its large tail surface throws it'll loop and stall-turn on a dime. Lots of fun... except the ailerons need some work, I reckon about 3 times the size they are now should see it performing well. Pictures/video another time.

Now, the StevensAero QuickOats 100! Lovely little plane I completed about a week ago and maidened a few days ago. Very forgiving and light in the air, and efficient on power as well. Landings are easy on almost any surface and it still has enough power to loop (with a runup) and turn quickly.

Well, heres the video:

Stevens Aero 'QuickOats 100' - Sunsent Flyer (2 min 11 sec)

And a (dodgy phone camera) picture:

The latest and greatest is my inspired F-15:

Its made out of simple 6mm/.25" posterboard and hotglued together. The construction is fairly heavy-duty, and seems to hold together well. I reckon high-g loads for this baby wont be a problem. It'll be powered by the following:

Hextronik 24g 1700kv brushless outrunner
HobbyKing 'Super Simple' 25A ESC
Zippy 3s 1000mAh 25C lipoly
OrangeRx 2.4ghz receiver
HXT900 servos
GWS...Continue Reading
Posted by boingk | May 10, 2011 @ 01:19 AM | 10,760 Views
So, the Bluw Wonder Bipe got maidened just then.

Resounding failure, wings off and struts broken. Should be able to repair but to be honest I don't think I could be bothered. Might've looked impressive in the air but it was a pain in the ass to fly.

I think I will stick to more traditional builds from now on, or at least simpler ones until I get used to building with sheet foam.

Cheers - boingk
Posted by boingk | May 09, 2011 @ 11:37 PM | 12,207 Views
Heres the Pitts Special I've been working on, plans courtesy of the Back Yard Outdoor Bipe thread.

This is for the tech heads. Wingspan is 32.5"/825mm and area of 28.5dmsq. AUW is 308 grams/10.85 ounces. Max power at 17A is 150W output, with a static thrust of 20+ ounces and a pitch speed of 125kmh/78mph. Dynamic thrust at pitch speed should be around 6 ounces. Gnarly.

All that mumbo-jumbo translates into this thing looking like it should fly pretty well to say the least. For the more practical people, heres the running gear you can see in the above picture:

Hextronik 24g 3000kv outrunner
HobbyKing SS 15/18A ESC
OrangeRx 2.4ghz receiver
Zippy 3s 1000mAh lipo
HK15168 (9g) servo (elevator)
HXT900 (9g) servo (rudder)
APC 5x3 prop

I've fitted some landing gear for the maiden as I prefer to get a feel for what the aeroplane wants to do while its taxiing, rather than hand-launch and hope for the best. Usually the latter results in at least one crash before you sort things out. I don't particularly want to do that so landing gear it is for the maiden. They'll most likely be removed afetrwards and the CG noted so I can adjust accordingly.

It'll most likely stay RET (Rudder Elevator Throttle) controlled until I work out any and all bugs and trim correctly. After that I'll go about adding some ailerons to the top wing, controlled via a single central HK15178 (10g) servo.

One last comment before I go maidening this thing is that it'll definitely not stay white. I'd like to paint it red or perhaps green, with some white line patterns on the underside of the wings. If anyone can suggest a good paint/marker etc for this Depron type foam it'd be much appreciated.

Cheers - boingk
Posted by boingk | May 06, 2011 @ 05:22 AM | 11,070 Views
Today there was a large package waiting for me at the postoffice. Looked like that F9F Panther I'd ordered, so I eagerly got it home... and on opening it started building that F9F.

It went together in the quoted time of about an hour, but there were a few things I though needed doing before the first flight. One of them was that the battery compartment wasn't just big... it was huge! My Zippy 3s 1000's would fit well, but would slide forward and aft during aerobatics or speed changes, altering the centre of gravity. THis was fixed with takeaway container plastic sut to size and glued into place as battery compartment firewalls, limiting its movement to only a few millimetres fore and aft.

The receiver was velcroed to the underside of the canopy insert as there was no oher spot. This proved adequate for flight out to visual limits.

On inspecting the control horns, I though they could use a bit mroe glue, so tacked them up with some 5 minute epoxy that I'd used for the assembly of the airframe.

The last modification wasn't neccessary, but I do it to all my belly-landers to keep them looking presentable. Its simply an addition of clear packing tape to any surface that will touch down during landing - in this case the lower fuselage and wingtip fuel pods.

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