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Posted by A Useless Geek | Oct 16, 2017 @ 03:08 PM | 1,463 Views
Okay, I know I've fallen down on the job of keeping up this blog. I got a "life" (such as it is) to deal with, you know. Anyway, the next evolution of the Parkstar looks like this: welcome to the Parkstar Advanced.
Posted by A Useless Geek | Feb 25, 2016 @ 01:53 PM | 4,188 Views
My opinion of these things kept changing because of various results I was getting. However, after messing with three of them I have finally come to the conclusion that these pre-made frames with integrated ESCs are quite all right. They have to be assembled properly and the ESCs set up and calibrated correctly, but once that's all done they work just fine.

The "Micro Integrated PCB w/ESCs Quadcopter Frame" is a 235 sized fiberglass frame that can handle up to about 6A per motor. They spec the ESCs at 8 amps, but you are a fool to push them that hard. At 6A they work just fine. Check out the various threads where guys have changed the FETs to handle more current if you want to get radical.

I don't know the exact firmware on these guys, but they come out of the box talking to the white Turnigy programming card. You can calibrate full range on all four ESCs at once with the normal quad calibration hookup, where you take one ESC's BEC output to fire up the receiver and just pass the servo signal to the other three ESCs at the same time.

The outer arms should be bolted together with steel M3 screws instead of the plastic ones because any hard landing at all will break the screws off, leaving the stubs stuck in the plastic standoff. It's not hard to get those out, but why let the screws break in the first place? Just use steel.

The motor mount through holes are sized perfectly for Turnigy 6mm bearing tubes, so any 1811 or 2211 series motor will fit through...Continue Reading
Posted by A Useless Geek | Dec 07, 2015 @ 02:01 PM | 4,258 Views
So, I did another quad using 6mm CF square tubing notched like my Stick Simple/Woodie layout. It was okay, but the real advantage came after I added epoxy to the corners to stiffen everything up. I just put another five minutes on this thing and it works well enough that I almost think it almost has almost enough oofta to almost be almost competitive in 250 Race. (Of course, I actually know better.)

245 rotor-to-rotor
Turnigy 1811-2000 motors
Turnigy Plush 6A ESCs
Nano-tech 850 3S 25C
CF square tubing, strengthened with JB Weld and microballoons for the corners
165 grams dry -- not bad!


Okay, I'm officially done with MultiWii flight control boards. This is the third one that has stopped working after a few not-too-hard crashes. Why is it that the KK2 board handles crashes just fine but the MultiWii gives up the ghost? Whatever.
Posted by A Useless Geek | Feb 24, 2014 @ 11:23 PM | 5,931 Views
So, last summer my HK Mini quad PNP came out of the box with a KK2 board on it and all the ESCs soldered up, yada yada. The very first flight I hovered it over the driveway for a bit then tried a little rocket. I mean, just a little rocket, like I wanted it to shoot up a meter or so. The durn thing went three meters into the air and flipped over about six times before coming down hard in my neighbor's front yard. Broke one arm off at the end. Total flight time: about ten seconds.

The damage revealed some outstanding weaknesses in the HK design (which I presume they just bought off of somebody else, but who knows). For one thing, the arms are not structurally sound out at the ends where the motors mount. There is no longitudinal bracing for the arm after the point where the ESC solders on. The fiberglass of the circuit board is neither strong enough nor flexible enough to take the stresses of a less-than-perfect return to Earth.

In order to fix my unit I had to do some surgery to the outboard end of the arm and attach a pile of CF strip and square tube to make the arm both strong and stiff enough to handle the stresses of a quad. I scraped away some solder mask on the bottom side of the board and made sure the top side was ready to accept CA. Then I tacked on some CF strips on the outside of the vertical portion of the arm. Once I had the arm end positioned properly I added some square tubes on the inside. The whole mess got a substantial blast of thick CA to bind everything together and form a solid surface to spread out stresses.

This thing works now, but I'm not really happy with the performance. My MultiWii quads are outperforming it right now. Maybe I just need to do some more tuning. Whatever.
Posted by A Useless Geek | Nov 06, 2013 @ 12:23 AM | 6,073 Views
So, now I've got a UDI 816 micro, two WL Toys V929s and a Syma X1, and three scratchbuilts. It's getting crowded in Quadland, Illinois. Now I need to start ordering props in bulk from Banggood, HK, etc. I go through a lot of them.
Posted by A Useless Geek | Oct 30, 2013 @ 10:15 AM | 6,291 Views
Okay, so my littlest scratch quad wasn't behaving all that well. I started out with a HK I86 board running four Turnigy 1811-2000 10 gram motors on stock Plush 6A ESCs. The thing would spin, and roll over, and generally play dead. Not phun.

Then I switched to a HK MultiWii control board.

Shazam! Suddenly the Little Quad was a docile, easy to fly package, almost like those commercial brushed minis. However, the Little has a bunch more performance, like a WLToys V929 or Syma X1 on steroids or cocaine or something. I am very happy. This gives me a transitional quad on which to learn more advanced flying techniques without the expense and hassle of constantly fixing a bigger quad with more mass, more expensive props, etc. Verrrrry nice.

-- Construction --
(4) Turnigy 1811-2000 motors
(4) Plush 6A ESCs
HK MultiWii flight control board
OrangeRX R615 Spektrum-protocol receiver
HK 5x3 counter-rotating prop set, red
HK 5x3 counter-rotating prop set, black
Custom-built frameset, with tie-wrap landing skids

-- Specage --
Dry weight so far: 125 grams
AUW with nano-tech 850 2S 25C: 174 grams
Shaft-to-shaft: 270 mm
Flight time: 6 mins or so, maybe longer -- I keep crashing and doing silly stuff
Posted by A Useless Geek | Aug 15, 2013 @ 08:39 PM | 8,573 Views
So, I got a FlySky module for my Turnigy 9XR, the radio I am using to replace my Spektrum DX7s pile of scrap (POS). The 9XR is a nine channel radio with a whole lot more control capability than the seven channel DX7s could ever pretend to have, and even more than the DX8 claims.

The only thing is, in order to get the 9XR to properly control my Syma X1 mini quad I had to reassign the channels to make the 9XR look like an old 72 MHz FM radio. If you are using a 9XR to run a quad set your radio up as follows:

Page 5 [MIXER]

Channel Order: AETR

After that yer quad should respond properly. You may still have to play with servo reversing (had to reverse elevator on mine) but it will be pretty obvious. Also, on my Syma I put the mixer settings all the way up to 125% to try getting more control out of the quad, but it only has so much.
Posted by A Useless Geek | Feb 22, 2013 @ 02:24 PM | 7,719 Views
A lot of people have asked me about plans for the Longhorn. Well, I ain't gots no plans because I'm a Lazy Bumģ. However, I have some images to show the dimensions and some instruction on how to build one:


I've made some changes to the way I assemble these planes now. One thing is I eliminated the fuselage spar in the back by extending the horizontal stab with a strake. This spreads the stresses out and prevents the fuse from breaking without adding the mass of a CF or spruce spar. Another change is to go back to the laminated fuselage made from two pieces of 6mm foam with a bit of sheer nylon curtain material in between.

Of course, this depends on using the right material: Model Plane Foam. This stuff has the exact right properties to build a plane that's flexible enough to bend without breaking, but stiff enough to support the kind of crazy performance for which the Longhorn is known.

Iíve discovered a lot of phunky properties of this plane, but havenít recorded a lot of my experiences yet. Let me take some time to sort this good stuff out and Iíll eventually add everthing Iíve found to this thread. In the mean time, build a Longhorn for yer own bad sef and make your own discoveries!
Posted by A Useless Geek | Feb 22, 2013 @ 12:04 PM | 7,321 Views
So, the Barnstormers had a Fun Fly out at the dome last night, with the contest being a Balloon Break. In this case we used balloons suspended from a catenary pole held aloft between two end poles. Lots of people flying all kinds of aircraft trying to get between the end poles first, under the catenary second, and targeting the balloons last. More than a few collisions between folks going for the same balloon. General hilarity ensued. I had more phun than I've had in months, and laughed hard enough to split a seam.

But poor ol' #4 was the victim in all this frivolity. I guess 176 qualified flights (minimum five minutes, contiguous, not interrupted by damaging crash requiring other than a prop change) was enough for that airframe. I got clobbered by multiple aircraft, bounced off the poles a few times, and only popped two or three balloons. Oh, well.

My next Longhorn will be made from MPF, of course. This one will have some fairly high dihedral to promote tight spirals and wicked turning response. I still have one old unit made from PBIII and Pink, but that one doesn't get used very often. I'm thinking of giving it away.
Posted by A Useless Geek | Feb 12, 2013 @ 04:35 AM | 7,726 Views
So, I'm thinking about a stupidly fast foam plane for the summer. I've seen folks going pretty fast with Multiplex Funjets and such, but my target is 300 KPH, about 186 MPH. I'm not interested in any kind of hotliner, since those things just look too ugly to me. I want to build -- or at least assemble -- something jettery with a single motor and a single prop. Not an EDF, not a turbine. A prop.

It's fairly easy to get small stuff to go relatively fast. I built a perversion of a Pinkstar with a Blue Wonder 3000kV motor that does in the 60 MPH range (haven't instrumented it yet), and that's not even trying very hard. (60 MPH doesn't seem very fast outside, but in the golf dome it's at the limit of my abilities.) Lots of folks have pushed scratch Funjet clones of various types to the 200-250 KPH range. What does it take to get over the cliff and hit 300?

Suggestions welcome.
Posted by A Useless Geek | Nov 08, 2012 @ 04:36 PM | 7,845 Views
Okay, so I've been playing with that WLToys ICopter for a while now. Yesterday I managed to "land" the thing upside down on the driveway hard enough to crack the bug shell in half. Uh, oh. Gonna hafta add some protection to the board on the top side now.

But I've got enough quad time under my belt that I want to move up to something a little bigger and better. To that end I have a few multi frames that I'm building up. Only two flight controllers right now, but that'll change with my next Hobby King order. Of everything else I have plenty, but the flight management is hard to come by.

The three quads are a Holybro Hobby X-230, a Hobby King CF Talon, and a Hobby King fiberglass X666. The tri is from Scott Hall, aka Hall Effects. [cough]

(As a side note, those two frames are only modified by Hobby King. They are not the OEM.)

We'll see how this goes.
Posted by A Useless Geek | Oct 22, 2012 @ 06:25 PM | 7,770 Views
'Nuff said.
Posted by A Useless Geek | Sep 15, 2012 @ 02:12 AM | 8,180 Views
sr71fan, one of my R/C heroes, has been flying a lot of symmetricals lately. Now, Gary can fly anything and make it look like phun regardless of how well it flies, but these symmetrical jobs have always appealed to me anyhow. Maybe it's the rocket-like shape that harkens back to my rocket daze. Whatever. I love the cool presentation of these planes; the way they look the same along any axis; and the way they can flip-flop from up to down to sideways and just cruise along regardless. Far too cool.

So, I started my own symmetrical build last year. [cough] Haven't finished it yet, but at least it looks like something that's actually in process. Note that this plane got started before MPF was available, so it's made from FFF and not Adams. The next one for sure, eh?
Posted by A Useless Geek | Jun 13, 2012 @ 02:47 PM | 8,185 Views
So, I realized that my box of sub-100 gram motors was getting pretty full. Okay, some of these are committed to upcoming planes, both mine and others', but the bulk of them aren't dedicated to anything in particular. Keep in mind that this is only about four years' accumulation. What's going to happen over the next twenty?
Posted by A Useless Geek | Jun 13, 2012 @ 02:02 PM | 8,453 Views
So, I finally finished my first plane made exclusively from Adams material through Model Plane Foam. The plane came out as 154 grams dry, right in line with the rest of them. I went back to a doubled-up fuselage with a piece of shear nylon curtain fabric in between the two layers. Instead of using a CF or bamboo brace in the back I went with a strake on the horizontal stab. We'll see how this one holds up.

I made a couple of boo-boos when constructing this plane, so it isn't as great as the rest of them. For instance, when using a flame thrower (cigarette lighter) to shrink the tubing for the control rod ends I managed to melt some foam. Twice. Don't accuse me of being overly smart.

But even with the screwups in construction and layout the plane performs well. It's a Longhorn, and it's kinda hard to make one of these not perform well.
Posted by A Useless Geek | Feb 10, 2012 @ 12:23 PM | 8,887 Views
I finally got my Hobby King Quattro to add to a couple of Accucell-6s that I already had. (The older one had a phunky phan, so I took the cover off for cooling.) Now I can charge six packs at a time with fully programmable convenience. I also have a handful of fixed-current chargers that I can use for some other packs, but those aren't very accurate nor reliable. 'Sokay, six at a time is prolly all I'll need. Heh.
Posted by A Useless Geek | Dec 29, 2011 @ 03:11 PM | 9,082 Views
Yeah, well, I keep shifting around the planes hanging on my wall. Planes come and go as they get built, go downstairs for repair, get destroyed, go on a long-term storage shelf, or whatever.

So it goes.
Posted by A Useless Geek | Oct 22, 2011 @ 03:12 PM | 9,535 Views
Well, okay, I do seem to make an awful lot of these "loaner" planes, but I keep running into people who need something like this to learn how to fly. This is something I whipped together from cutoffs from other planes. I wanted to make something pretty light without resorting to "exotic" parts and materials.

To that end I used standard 6 mm Pink, 14.5 mm Pink Foamular (the old, light, soft stuff) for the fuse, a bamboo shish kebab skewer to keep the back end from breaking off, and some other standard junk. The light ply for the motor mount plate and backing plate are cutoffs from bigger planes. The piece of EPP for the motor shock mount is just plain scrap, it's so small. I heated up some used Velcro to make it stick to various places on the airframe, but used new stuff for the battery mount. 0.032" piano wire through coffee stirs forms the control setup.

The tail surfaces are held on with Beacon Fabri-Tac. The main wing is held together with foamed-up yellow Gorilla Glue in the center. The wing is held to the fuse with toothpicks and CA. The bottom of the fuse is taped with 3M Extreme tape to keep it stiff and to prevent landing rash. (The 1/2" Pink stuff is really, really soft.)

This plane came out a little heavier than I really wanted, but that's what happens when you use standard materials rather than 3 mm Depron, CF, and other stuff that costs a bunch of money. I'm trying to get some building techniques down for the use of those...Continue Reading
Posted by A Useless Geek | Sep 27, 2011 @ 02:45 PM | 10,478 Views
So, I was cutting out wings for a pile of Pinkstars and ended up with these two cutoffs that looked like moth wings. Instant "brain" (as I like to call it) storm: a slow flyer that uses big, fat wings. How original. Here's what I ended up with:

Span: 880 mm
O/A length: 784 mm
Mass: 168 grams
Motor: Turnigy 2204-14T (19 gram, 1400 KV)
Prop: GWS 8x4.3 EP slow (EP-0843)
Servos: hexTronik HXT500 x 2
Rx: OrangeRX 6 channel, minus useless plastic casket dead weight

The surfaces are almost completely 6 mm Dow Protection Board III. The fuse is 1/2" (actually 14 mm) Pink Foamular. 3M Extreme tape holds the whole airplane together, particularly in the back where I used no spar embedded in the fuse and paid the price for that. I actually broke the plane in half by holding it up from the tail surfaces. After using foamed-up yellow Gorilla Glue to put it back together I added tape to hold the tail end stiffly into place. Duh!

So, now I've got another plane to loan out to people trying to learn to fly. I'm not really happy with the stall characteristics of this plane, so I can do one of two things to fix that; either add a KFm2 step on the top side to make it fly slower and have gentler stall, or cut the wings back to a Skinny Boy configuration (there's plenty of meat on the wings to achieve that shape) and have the plane actually fly a little bit faster, but with easier handling characteristics. I don't know which approach I prefer. In either case I ain't gonna be the one flying this plane a whole lot.
Posted by A Useless Geek | Jun 05, 2011 @ 11:18 AM | 9,875 Views
This thread may get a lot of traffic, or none. Who knows? I'll keep updating as I get more photos made of assemblies on which I'm working.

To start with, let's take a look at how I build wing assemblies for the Skinny Boy, Eluder, Longhorn, Lunatic, etc. These are flat pan wings with a dihedral in the middle. The wing roots are cut at an angle so that they meet in a vertical line when the halves are put together. The underside of the assembly gets support from balsa trailing edge wedges cut down to size. After the wedges are put in place the entire underside of the wing root is sanded flat to meet with the flat top of the airframe.

Put the wings top down on a flat surface, then use blue tape down the centerline to hold the assembly together. Flip the wing over and apply puffed up Gorilla Glue to the seam. Weigh down one wing and prop the other one and the correct angle. Prevent the GG from puffing up too much on the top side by applying blue painter's tape. (The cat isn't necessary, but may help relieve tension.) The extra GG puff on the top side of the wing supports the wing during high G maneuvering.

Balsa trailing edge wedges are available at the LHS in long strips. Use a slitter to cut them down to size. You only need enough width to make contact with the top of the airframe, typically 10-16mm wide depending on what you are using. Glue the wedges along the underside of the center seam. The thin edge goes toward the center. The idea is to make a flat surface so that you can glue the wing to the airframe without gaps.

After the glue is cured you can sand the underside of the wing root to get a completely flat surface that can then be glued to the top of the airframe. You gots a basic airplane!