Posted by boingk |
Nov 11, 2011 @ 09:50 AM | 4,979 Views
Sitting here listening to an assortment of Boston, Kansas, BOC etc and drinking a casual beer after a shift at work, reflecting on the day. Sometimes I like to write and relax, not doing anything in particular.
I've had a bit of a repair session so have flown a few planes I haven't in a while. First I took up the HobbyKing/Lanyu J-3 Cub... yeah the yellow one in the other blog entries. Current powertrain is a 2810 1700kv outrunner on 3s 1000mAh lipos with GWS HD 8x4 props.
It flies like an absolute champ! After repairing the motor mount and other assorted areas, I babied her into the air on a lazy Friday afternoon. Took off and did rather 'scale' flying around the lot, throttling up to do a loop from level flight every now and then. Total flight time was a hair over 10 minutes, and total charge put back into the lipo was 600mAh... I think thats a new efficiency record for me with a 38"+ craft. Anyway, it was a lot of fun and very relaxing... much as typing this is.
Next up was my Artech/FMS/Whatever Mini P-40, repaired with new ESC after the stock one went south. Flying on a 3s 1000mAh pack it performed very well, but reminded me what a heavy damn pig of a thing it is to man-handle around the skies; this sans landing gear and rudder linkages/servo! It might look the part but I certainly can think of better things to fly, especially if I'm after a relaxing flight.
I will say, though, that the P-40 can take a fair bit of abuse without needing a new airframe....Continue Reading
This was initially a post to help out a fellow whos making an elaborate and very well thought out first time FPV system. His budget is also rather elaborate, at around $1000. I know that kinda cash isn't so readily available for most (myself included) so thought I'd post up my first time FPV system which is a lot more budget freindly, yet still gives you room to grow with it.
For starting out my setup is as follows:
38" HobbyKing EPS 'Old Timer' J-3 Cub
5" LCD screen / Turnigy FPV goggles
5.8Ghz 200mW Tx/Rx system
The video setup is the 5.8Ghz/200mW system HK sells, coupled to a cheap CCD caseless camera. Thats powered by a 3s 360mAh lipo pack at the wing root, easily changed and voltage checked before each flight. My viewing monitor for first flights is a small (wallet sized) LCD screen to get used to FPV - most of the flight will be ground based visual flight only. Later I plan to switch to goggles and have some cheap ($70) Turnigy ones on the way. Headplay 800x600's ($300) are what I really want to get eventually.
Control is not going to be by my DX6i - while I like it as a transmitter for ground based flying, I do know the limitations. Personally I'm getting consistent ranges of over 500m but I do know that can vary and wouldn't like to lose a plane. On the way I have a secondhand 36Mhz JR computerised transmitter and a few receivers. With a few simple modifications (longer receiver antenna, LiPo transmitter pack) this will get me...Continue Reading
Posted by boingk |
Aug 01, 2011 @ 08:38 PM | 6,600 Views
Thought I'd better make an entry on my flying wing, seeing as I've added another engine to it and all. The original plan design calls for one engine in the central position, mounted on the forward face of the battery/ESC housing box. This gave more than enough power for the airframe, even with a 1000mAh, 3oz/90g flight pack weighing it down.
I removed the central motor and streamlined the battery box, then added two motors to either side with enough clearance for a 6" prop each. They're 24g 1700kv Hextronik outrunners, each coupled to a 20A ESC. This allows a max loading of a 6x4 prop with 4-cell operation, which will give some nice speed and a whole heap of thrust. Pushing it would be to swap out to a 5.5x6 or similar and get a pitch speed of 120mph and enough thrust to pull you up with it!
So here it is:
To accomodate the larger battery needed to sustain a peak draw of 20~30A I had to removed the ESC's and receiver to the rear portion of the wing by adding some balsa platform stays inbetween the central ribs. I glued them to that and it seems fine. I'd recommend either a 1500mAh 3-cell or 1000mAh 4-cell lipo for this fellow to balance it out - the 1000mAh 3-cell packs I maidened it with didn't seem to give quite enough forward bias.
Anywho, video to come at some point so stay tuned.
Posted by boingk |
Jul 27, 2011 @ 12:32 AM | 6,487 Views
Update on the powertrain for the HobbyKing 'Ep Old Timer' night flyer project. I've decided to use a 1700kv motor seeing as it'll give some better prop options for both speed and thrust.
Preferred prop combos with this setup are 6x4 and 7x3.5 - the latter the one for slow, cruisey 'beer-and-a-deckchair' kind of flying. With 4-cell pack and a 6x4, it'd be a lot better for aerobatics and still only have a 16A max current draw.
Posted by boingk |
Jul 25, 2011 @ 12:46 AM | 6,519 Views
So winter is well and truely here in Australia and the winds are up in the highlands. At night they usually calm down so I thought I'd exploit this by building a cruisey night flyer from the HobbyKing J3 'EP Old Timer' ARF:
This is identical to the J3 'Green' I bought from them at the start of the year to learn on, and I enjoyed that very much as a trainer so figured itd be a good mount for night flying gear and perhaps as a future FPV plane given its stable flying.
The night gear I've ordered is also from HobbyKing and is simple a few bundles of LED strips that are designed to be run directly from unused channels on your receiver. A standard 6-channel 2.4ghz receiver will have three unused Futaba/JR sockets in a 4-channel aircraft (Batt/Bind, Gear, Auxillary) and four unused socket in a 3-channel plane so these little fellows are perfect:
I've ordered sets of green, red and white lights to fit to the wingtips and tail of the J3 so I can properly orient it at night and also have a somewhat scale appearance, rather than just drape it in glowtube or LED strings.
Powertrain for the J3 will be the same as the ultimate evolution of my first HobbyKing J3 - a 24g Hextronik 1500kv outrunner with 7x4 prop (GWS EP/DD 8x4 cut down) and 3-cell 1000mAh lipo pack. This setup gave me good thrust and decent speed for aerobatic maneuvers and I've no worries with using it again.
The setup was a bit too nose-heavy with a Flightmax 350mAh 2-cell so I used a 180mAh pack instead, which is what it is flying with in the video. I managed around 8 minutes flying time - mostly at half throttle - before low voltage cutoff and the performance on tap was brilliant. Loops, rolls and Immelmans were all very snappy and the low-speed and gliding characteristics were nice, too.
Posted by boingk |
Jul 07, 2011 @ 02:16 AM | 6,395 Views
Well, following the current obsession with flying wings I've decided to modify the original 'Electric Canary' wing into one, and to hell with the plans to make a small low-wing aerobatic plane. If I feel like doing something along those lines I'll just add a tail boom and move the motor forward a few millimeters.
So, you might recognise the wing from a few posts back:
The plan is to make this an 18" flying wing with the same power system as the small 15" version in the last update, but possibly on a 3-cell lipo pack if I can accomodate a Rhino 3s 360 in it. This may also help with CG should I decide to fit a tail boom. Even if I scrap it as a flying wing and convert to a full fuselage, low winged aerobatic model I can use the dual aileron servos to program flaps.
So... thats it for the Electric Canary, but there is progress on the 15" version:
The model is now only awaiting vertical stabilisers, control links and elevons. Unfortunately I forgot to cover the wing before cutting the stringers and adding the motor box... so the covering on the top side is quite average. I may redo this as the trailing edges are pretty woeful, but then again I may not. Part of the complication arises from the fact that I'm only using a regular household iron, which is cumbersome at this scale.
Anyway, more as it happen. Maiden might not be for some time due to galeforce winds striking this side of the country but I'll keep everyone posted regardless.
This is just something which is keeping me entertained between shifts at various pubs and bottleshops around town, sometime at work as well if its quite enough at the bottle-o.
The wing design is heavily modified from the '1/8A LaStick' plans and uses 8 full wing ribs in combination with another 6 leading edge formers, making for quick cutting and assembly. Coating will be transparent iron-on covering film, and it has a wingspan of only 410mm/15".
The power system is all cheap HobbyKing gear as I build on a strict budget. Motor is a 10g Hextronik 2000kv outrunner propped with a GWS 4.5x4 prop, ESC a HobbyKing 8A 'Super Simple', receiver a 2.4ghz DSM2-compatible 6ch brick. Servos are 3.7g HK 'MiniMan' units and the batteries are going to be Flightmax 2s 350's.
AUW with the setup as fitted so far comes in at 58g/2oz and should only climb up a bit to perhaps a maximum of 65g/2.3oz once covering and control linkages are fitted. Most likely it'll be somewhere inbetween.
I start getting into a groove at about 1:20 and realise there is something wrong at around 2:45 and land as best I can. The 'something wrong' turned out to be a dead servo, leaving me with very skewed handling indeed!
Following the flight above I've flown about half a dozen packs through it and also added some more detailing to help with orientation. Heres how it looks now:
The black parts are just drawn on with a permenant marker and the white stripes on the wing and square on the motor box are done using an automotive oil-paint pen.
Since refitting with a servo, I've started trying to trim mechanically for neutral flying without transmitter trim. This has proven to be somewhat of an effort and may require fitting a matching servo to replace the one still remaining from the original build - although the new one is equivalently specified, I think it may differ in speed and thus causes some trimming problems.
Anywho, thats the lot for now. Stay tuned for more as it happens.
Posted by boingk |
Jun 30, 2011 @ 03:50 AM | 6,738 Views
Well, I'm back. And that balsa wing I've been bantering on about? Done. Finito. Flown!
I'd originally decided to fit a Cox .049 glow engine to it but figured that since the majority of my flying is done in town it'd make a bit more sense to go electric. The setup I'm using is a HExtronic 24g 1700kv outrunner wth 7x4 prop, 15A ESC (18A burst) and 3-cell 1000mAh lipo packs. It seems to fly very well, the maiden flight was more or less hassle free - apart from one issue which I'll touch on later.
Anyway enough words, here're the pictures:
The last two are post-flight, during which I discovered that the reason for my flight into terrain incident about 3 minutes in was a dead servo. For some reason one of the servos was dead on the wing, leaving me with left and up or right and down as control choices. This made for a rather unglamourous landing.
Posted by boingk |
Jun 25, 2011 @ 02:30 AM | 6,684 Views
Hey guys, hows it going? All is good here, and lately I've been thinking about making a micro balsa and covering model. I was thinking about this for a while in nitro-powered guise (Cox .049) but that got earmarked for another project and I'm going electric for this one. It'll be called the 'Electric Canary', and is based on the popular '1/8A LaStick' plans here on the site - draw up by Dave Fritzke and Gene Rock.
There will be a few main differences in this model from the one that they designed. Notably, mine will not be a high-wing plane. It will have a low wing for sportsplane type control and agility. The other main change is that it will be roughly an 80% scale version of the LaStick, with an 18"/450mm wingspan in lieu of the Stick's 21.5"/550mm span. This should make for a lively little parkflyer thats a bit different from the usual small balsa model.
The thing that remains the least changed is the wing, although thats not particularly saying much.
It still has the same basic construction, although the stringers are very much simplified and are from the same stock for leading/trailing edges and the top and bottom, too. Some formers were left leading edge only to save weight, and at this scale the leading sections are uneccassary. The airfoil is the same as the original and the chord/span ratio is also the same. One other change I made was to put profiled tips on as it was as simple as cutting some extra foils, and lends a much classier look to...Continue Reading
Posted by boingk |
Jun 06, 2011 @ 01:40 AM | 7,267 Views
Latest efforts here have been on the 3D Gee Bee kit I got from HobbyKing a few months ago. I've been holding off completing it because I honestly didn't think I could handle a fragile 3D balsa plane until now. Well, the time has come (the Walrus said, to go fly other things!) and I reckon I'm ready:
These photos are taken after the maiden. I kept it on 3-channel only (aileron, elevator, throttle) and it didn't seem to need any trim at all. The 2s/C20/8x4 powertrain has more than enough thrust for the little beastie, loads of fun. All control are very touchy even at low speeds because they've got large surface areas and throws, a bit challenging on a non-computerised radio but it survived!
Worst thing to happen on the maiden was a rough landing. I damaged the prop tips but thats all. This looks like its gonna be a blast, I'll try and get some video of it up.
For those interested in the setup its as follows:
C20 motor w/3mm adaptor & 8x4 GWS prop
12A Blue Series ESC
Rhino 2s 20C 750mAh lipo
HK 2.4ghz DSM2 compatible receiver
HK15168 servo for ailerons
TGY-1440A servos for rudder and elevator
The programming settings for the ESC are high timing, instant startup, no rpm limit, sharp throttle response and power decreased once 3.2v/cell is reached. This gives smooth running for the motor and very responsive, punchy performance.
I have not programmed my controller for any expo or dual rates or anything like that as I just use a basic DX5e and...Continue Reading
Posted by boingk |
May 30, 2011 @ 11:27 PM | 7,250 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 rcfoamfighters.com 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.
Posted by boingk |
May 24, 2011 @ 09:52 PM | 6,572 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.
Posted by boingk |
May 23, 2011 @ 02:51 AM | 6,675 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.
The latest and greatest is my rcfoamfighters.com 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:
Posted by boingk |
May 09, 2011 @ 10:37 PM | 7,294 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:
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.
Posted by boingk |
May 06, 2011 @ 04:22 AM | 6,690 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.
With the HK GeeBee complete and awaiting pushrod material, I thought it'd be a good time to start another model. I've been interested in IC engines for a while and after ordering a Cox .049 and an AP .061 I started to build a wing from scratch.
Plans are here and materials used were 6 & 3mm square sticks, trailing edge section balsa stick and 3mm balsa sheet for the ribs. The fins are 1.5mm balsa layered up to 3mm, with an third part-layer on the outside. I left out the shear inserts because I didn't think they were neccessary. Heres the progress:
Made a few posts about this a couple weeks ago in the 3D and Sport Planes forums, and the other day the package showed up. Its a new offering from HobbyKing and their first true balsa kit. I got stuck in and heres where I am now:
The HK 3D GeeBee is dead easy to put together and takes me back to when I was a kid, making an Osprey (sic?) from a balsa kit and finishing with a tissue/dope covering. Only needed a sharp knife to trim pieces from the sheets, CA to adhere them and covering film & an iron to finish. No problems with fit at all, although I'd recommend using a 9g servo in the wing instead of the 5g they recommend as it a) fits better and b) will be better able to withstand the aileron flight loadings. 5g are fine for the elevator and rudder.
I've still got to fit all the electronics properly but linkages etc are ready to install after plugging some horns into the control surfaces. The recommended C20 motor fits well once you trim the fibreglass base at the inside edge of the mounting holes, and should deliver over 400g of thrust with an 8 inch prop on 2-cell drawing 10 amps... massive overkill seeing as it'll weigh 220g or so ready to fly.
The plan at the moment is to use this as a regular sport-plane and 3D trainer, as I have no experience with 3D flight except for some mild vertical and prop-hangers on my L4. I mean, I'm alright with loops, rolls (axial/barrel), stall-turns, inverted flight and other sporting maneuvers, but am yet to properly hover and so on. Hopefully I don't wreck the plane up too much learning, any advise would be much appreciated.