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thomanie's blog
Posted by thomanie | Jan 07, 2014 @ 04:20 PM | 4,156 Views
The Great Planes Laser Incidence Meter is a great aid getting your incidences right when building a model. That said, it could be better!

The major drawback is that the pivoting laser pointer needs to swing freely. Mine really never did, often causing a wrong indication due to binding or other issues. It (kinda) works when you know about it, and measure trice.

With the arrival of digital angle gauges like the Wixey, I wanted to digitalize my GP Incidence Meter. I drew up this 4-piece platform, cut from scraps, and glued together. A suitably sized blind-nut, and nylon screw to hold it in place, and we have ourselves a digital incidence meter. The hole is about 0.5mm / 1/64" too big each direction to make it slide freely on the bar stock. Epoxy some washers to the base for the angle gauges magnets to hold it in place. The attached pictures should be self-explaining.

Yes - the GP meter has been discontinued, and you can buy digitalized incidence gauges ready made from H9 and a couple of others, but DIY is a lot more fun in my book

Enjoy!
Posted by thomanie | Nov 15, 2013 @ 01:53 AM | 3,878 Views
Anyone into CNC needs a good g-code converter - the utility that converts the lines and circles of a vector CAD drawing to g-code instructions for a CNC machine.

Toolchain
In my free CNC toolchain I've been using ACE Converter for conversion, and the free version of NCPlot for backplotting, or visualization. ACE Converter apparently isn't kept up to date, and NCPlot is no longer available for free. So I've been looking for alternatives. Commercial CNC software packages often offer gcode conversion functionality built in. You can open the CAD drawings directly, convert to g-code, and run the machine with the machine controller software. LinuxCNC doesn't (yet) have this functionality built in, and needs the additional conversion step done manually before loading the file in the CNC software. LinuxCNC does have decent g-code backplot functionality with its built in graphical user interface Axis.

dxf2gcode
Still needing a good converter I took a closer look at dxf2gcode. In short - it works great!

Pros:
- up to date
- backplot functionality
- configurable depth for multiple passes
- layer and shape control
- cutter compensation
- cross platform
- free

Cons:
- very limited backplot functionality (top view only)
- some minor bugs/quirks

dxf2gcode handles recent DXF specifications. It allows for complete control over what layers, even shapes, to include, and has good options for controlling the mill depth. Multiple passes are automatically created if needed. You...Continue Reading
Posted by thomanie | Nov 02, 2013 @ 07:57 AM | 4,778 Views
I've been playing around with hobby CNC stuff on the side for a while. As this is hobby, I've been trying to keep cost down for my projects.

CNC lead-screws
One of the more costly parts of any precision CNC equipment are the leadscrews and anti-backlash nuts. The leadscrews are often referred to as "acme screws", which normally describe a trapeziodal threading screw with a steep incline, and low TPI (threads per inch). This is opposite to your regular 2-56 or metric M6 screw, which have a shallow incline and high TPI. For any given number of revolutions of the threaded rod, the nut will move further on a trapeziodal lead-screw, than it would on a normal threaded rod. A low TPI gives the CNC machine greater speed - for the exact same reason.

That said, I've had good results with using plain M6 metric threaded rod for my HobbyCNC gantry router. Metric M6 normally has 1mm travel per thread revolution, which makes for easy math. But going cheap here brings some additional issues.

Backlash
With regular threads like M6 threaded rod and there is also a considerable amount (in CNC terms) of play between the threaded rod and the nut. This makes it easy to enter and turn the nut for a person, possibly without tooling, but it also introduces what is known as backlash.

When the threaded rod moves the nut along one axis, the nut is resting on the aft wall of each thread. Whenever the CNC machine reverses direction, the threaded rod moves in the nuts thread without moving...Continue Reading
Posted by thomanie | Sep 22, 2013 @ 04:01 PM | 4,534 Views
I wouldn't expect you to, but in case you have followed my blog you've already seen my earlier attempt at a 4-axis CNC foam cutter.

First futile fumblings
The old design worked nicely for its purpose, but was clunky and took the opposite of sexy to the extreme... But it was a nice practice run, and proof of concept so to speak. Been wanting to do an improved build ever since.

Second attempt - CNC Compact
A while ago I came across the french CNC Compact design. It's a real gem of a design IMHO - with lots of great details. I had to modify the design slightly for what I had available. Main changes being a wider metal straight edge for the X-track, and 10mm carbon tubes for uprights. Although very nice, the green acrylic of the original design was for simplicity swapped for plywood. As always, Charlie and Vicky at Manzano Laser did excellent work with the cutfiles.

After resting on the secondary workbench for a while, I finally got around to assemble the thing this weekend.

Parts used
- NEMA17 size steppers.
- Rollerskate bearings.
- Fender washers
- M8 nuts, washers and bolts.
- M6 threaded rod, 1mm traverse per revolution for leadscrews.
- M6 furniture insert nuts
- plastic hose
- 100mm wide straightedge used for X-tracks
- 10mm carbon tubes for the uprights.
- 1/4"-6mm model aircraft propeller adapters.
- M6 connecting nuts.
- 4mm plywood.

The long M6 connecting nuts, and propadapters, are used to connect the M6 leadscrew to the 1/4" stepper motor shafts....Continue Reading
Posted by thomanie | Jun 11, 2013 @ 07:32 AM | 6,625 Views
According to modern age songwriting there might be 50 ways to leave you lover - but there's really only 3 ways to sheet a fuselage with balsa when it comes to model aircraft.

How you sheet a fuselage depends on curvature. The amount and order of curvature determines how you can, and should, sheet the fuselage for the best end result. A sheeted fuselage normally consists of a series of fuselage formers, supporting longerons - smaller and thinner sticks that conform naturally to the flow of the fuselage, as well as the fuselage sheeting itself.

1 - slab sides
Slab sided fuselage are normally found in trainer or sport style airframes such as the classic trainer, Ugly Stick, or similar designs. A single flat piece of sheeting makes up the full fuselage side, with the grain running from the firewall up front, to the tail. This is by far the simplest and fastest sheeting method. The side sheeting may well be slightly curved around a motor up front, but its general property will be flat. The sheet will have to bend at the wings trailing edge to create the taper into the tail, and since a single flat sheet cannot conform nicely to a doubly curved surface, the sides will be flat. The strength of this design is (normally) largely in the sheeting, with less need for supporting structure of underneath.

2 - sub-panels
Curved fuselage sides such as normally found in scale(r) models makes for a slightly harder and more time consuming sheeting job. The fuselage...Continue Reading
Posted by thomanie | Jun 10, 2013 @ 05:02 AM | 5,416 Views
HobbyKing just released another Hitec Minima A-FHSS compatible micro 4ch rx. Although not confirmed, from the looks of it it's apparently from the now well renowned FrSky labs.

This small, parkflyer 4ch receiver has a range of +300m making it well suited for just about any parkflyer. Weighing in at 3.4g / 0.12oz, and being a tad longer and tad narrower than 1", it will fit just about any model except the very smallest ones.

With failsafe built in, and PPM and RSSI output available, it should be a great candidate for the Hitec A-FHSS crowd...

The picture is shamelessly borrowed from the HK website.

*Disclaimer: I don't have any affiliation with FrSky - just a blogging end user of some of their products
Posted by thomanie | May 28, 2013 @ 02:47 PM | 7,044 Views
I once again had the privilege to fly as an instructor at the Norwegian Aerosport Federations national glider flight instructor course. Tryouts and part 1 of the course lasted three days. Wicked nice weather for soaring with 3-4 meter thermals. Eager, well prepared and knowledgeable aspiring instructors also add to the positive experience. Great way to spend a long weekend.

The connection to model aircraft is is a long shot - a flying buddy brought an Alpina motorized glider for some evening relaxation.

Enjoy!
Posted by thomanie | Nov 22, 2012 @ 04:31 AM | 8,664 Views
HK Canary introduction
The HK Canary is a dirt cheap pod-and-boom style hand launch glider ARF available from Hobby King. With a wingspan just north of 120cm / close to 48", simple rudder and elevator controls, and a ready to fly AUW of a mere 310g / 10.9 oz this is a real handy size airplane. Observant readers will already have noticed the similarity to the long available GP Fling.

Equpiment used
- HK Canary glider (INT / US / UK / NL / DE / AU)
- 2x HXT 900 9g servos
- Corona RC R4FA 4ch FASST compatible rx
- 4.8V 350mah square rx battery pack (ebay)

Packaging
The kit arrived in a plain brown cardboard box. No flashy white box, nor product pictures on the box. Very dull and increadibly boring, but enables cheap. My box arrived undamaged.

Contents
For a mere 40 USD plus shipping you get a complete, ready built airframe consisting of
- 2x wings
- fin and rudder
- moulded fibreglass fuselage pod
- vacuum formed plastic canopy
- precut CF tailboom
- sticker sheet
- assorted hardware

Building
Closer inspection of the parts after unpacking revealed a surprisingly nicely built model. Wings are built from correct grade balsa for the job - not too hard and heavy nor too soft and light. Being picky my only remark would be that one wing was slightly heavier than the other. Wings are joined using a thick precut carbon wing joiner at the spar, and a smaller peg at the rear. Once connected, a band of clear tape or clear covering is added to the center section joint.

Tail...Continue Reading
Posted by thomanie | Sep 28, 2012 @ 12:31 PM | 9,320 Views
Over the past months CoronaRC has released a few FASST compatible receivers. Currently, there are 4, 6, 8 and 14 channel versions available. The 4 and 6 ch rx'es are in addition available in S.BUS capable versions. I'll be taking a closer look at the 4ch R4FA non-S.BUS version here.

Packaging and features
The receiver came in a cardboard backed, plastic retail package. Design-wise the packaging has a way to go IMHO.

The receiver itself has a dark, slight transparent, plastic casing. 2x2 rows servo connectors off the end of the receiver case, and the two antennae off the opposite end. The bind and F/S button is on the "rear" face of the R4FA. The first thing that struck me was that the rx looked thinner and felt lighter than the similar rx from the competition. Weight is spec'ed at 8 grams, I didn't bother actually weighing it.

The reciever supports both high- (HS) and low-speed modes, and support both FASST Air and FASST C1 surface systems. Supported input voltage is stated at 3.6 - 10V.

Pricing
The R4FA is priced at a tad less than the competing FASST compatible rx, but being this cheap the first place the difference is only a few USD. All in all neglible for most modellers. The big price multiplier comes from stepping up to the comparable legacy, brand-name rx.

Bench-testing
The receiver bound instantly after powering up on a 4.8V square receiver pack, while pressing the bind button. Servos moved smoothly as expected, without jittering....Continue Reading
Posted by thomanie | Sep 17, 2012 @ 02:10 AM | 9,732 Views
Great news for anyone with a Hitec 2.4G radio, on a budget. Two Hitec A-FHSS compatible receivers have just hit the streets. Hitec users have long been crying out for a cheap(er), aftermarket receiver, and the have finally been heard.

First there is an 8 channel standard sized, long range receiver. With HV capability (3.5 - 16V input), >1.5km range, and PPM and RSSI output, it should plug a black hole in the Hitec segment.

Secondly, there's the 2 gram micro 5 channel receiver. With micro molex servo connectors, 3.5 - 7.2V input voltage, >300m range, as well as PPM and RSSI output, this small sibling is aimed at the indoor or micro parkflyer scene.

There is no mention of telemetry capability for neither. Nor who the manufacturer is. But looking at the casings for both units, this does seem like the handywork of FrSky. If so, they will highly likely be very dependable units. However, there was no information on the FrSky webpages on these units at time of writing, so there's a slight possibility they come out of another source. As with any new product, they will have to prove themselves over time, but the pricetags and capabilities I'm sure they will fly off the shelves. Pictures are shamelessly borrowed from HobbyKing.

I don't own a Hitec radio, so I won't be able to test these - but stay tuned for online field reports on these units if Hitec is your game!


*Disclaimer: I don't have any affiliation with FrSky, or whomever the mfgr is - just a blogging end user of related products
Posted by thomanie | Aug 25, 2012 @ 07:30 AM | 9,704 Views
My kids are growing up fast - which is in a ways both a sad thing and a good thing. Conversing with your kids is one of a parents great joys. But, lets not derail completely...

Kids growing up often means all that baby stuff gets sold, given away, or in this particular case about to be thrown out. The IKEA Sniglar changing table had played its part, and the missus wanted it gone. Great! Finally! I'd eyeballed that changing table for a while.

Upper tray bottom was quickly pulled out, and my new low cost balsa storage bin was born. I still use some cardboard boxes as compartments in the bin, but this new bin sure beats the worn out cardboard box. I kept the wheels we mounted to aid moving it around when it served on the bathroom floor.

Additional modifications might be coming up as I see fit. One idea is to drill out the upper side frames and add wooden floral sticks in a criss-cross pattern to compartmentalize the bin to ease location of exact sized wood. There are also different changing tables available, that can also be modified in similar fashion.

So grab that chanigng table if it's getting thrown out. And if you don't have small kids, but still like the idea - the bin is about 30 USD at IKEA...
Posted by thomanie | Aug 15, 2012 @ 04:27 PM | 10,261 Views
If you've followed the EDF scene since its early days, you've most certainly made acquaintance with Andy Telzers Minx Mk2 EDF design. Cunningly similar to a Alpha Jet or Pampa, I dare say it was a design ahead of its time.

The Minx Mk2 was the 29" wingspan, smaller forerunner of the later 70mm Sport Jet ARFs coming out of China. The Minx Mk2 was designed for a brushed s300 running off a 7 cell NiMH pack. Yes, brushed. Not brushless. The original build article even had pointers to the homemade fan. Real old-school in other words. Why revisited? I built one back when brushed was starting to become cheap, and brushless was the expensive way of having fun.

Fast forward to today, and the brushed motors, heavy-as-concrete "round cells", and homemade fans are gone. Left are high power 50mm fans, hot wound brushless motors, high power brushless ESCs, and lipo packs packing serious power. Lastly let's not forget 2.4GHz radio systems. All this probably for less than the price of the original battery pack. But the airframe design still remains the same - the Minx Mk2.

Well almost, the same. Truth be told. I deviated from the plans with a fattened fuselage to fit the 3S lipo and 30A ESC, as well a built the powerpod using balsa and ply instead of the foam called for on the plans. Adding modern electronics from the parts bin resulted in the following setup:

- WeMoTec 50mm Microfan
- Hyperion Y22L 6000kv motor
- Turnigy Plush 30A ESC
- Turnigy NanoTec 3S 1300 mAh
- ...Continue Reading
Posted by thomanie | Aug 01, 2012 @ 04:55 AM | 10,885 Views
Hot on the heels of the newly released FASST compatible rx lineup from Corona RC, are two new S.BUS capable additions - one 4ch and one 6ch receiver. Sadly, once again there is no information on the Corona RC webpages about these offerings.

The latest two S.BUS additions are the 4ch R4FA-SB and the 6ch R6FA-SB. These work as normal FASST capable 4ch and 6ch receivers, but both effectively become 14ch receivers in S.BUS mode (12 ch + 2 DG channels). This puts some additional competitive pressure on FrSky and Futaba in the S.BUS space, which will eventually benefit us modellers as end users.

I still haven't seen many field reports on the Corona RC FASST capable rx lineup, but neither any catastrophic reports. So they look like an option to consider if you are in the market for a S.BUS capable FASST compatible receiver.

As there are is info nor pictures on the Corona RC webpages, the attached pics are shamlessly borrowed from the HK webpage.

Disclaimer: I have no affiliation with Corona RC, except being a blogging end-user.
Posted by thomanie | Jul 08, 2012 @ 09:02 AM | 10,384 Views
Corona RC has apparently been catching up fast on their 2.4G FASST compatible lineup lately. Sadly the Corona webpages are lacking info on most of this lineup.

Their latest addition is the R14FA is a 14ch FASST compatible rx. With a street price well below 40 USD, or less than 1/5th of the similarly spec'ed brand name rx, this looks very interesting for anyone looking for a 14ch FASST compatible receiver. To my knowledge this is the first true 14ch FASST compatible rx. Earlier the only option was to pair up 2 of the FrSky/OrangeRX 8 channel FASST compatible receviers to get 14ch reception. With the R14FA selling for about the same as the 8ch FrSky, the 14ch reception price was just cut in half!

Corona also has a 4ch R4FA, a 6ch R6FA, an 8ch R8FA. The R4FA and R6FA are apparently compatible with FASST surface radios too. Pricing is - not surpisingly - very close to the similar FrSky lineup. As the competition is turning up the heat, I wouldn't be surprised if we soon also see FrSky releasing a 14ch FASST compatible rx. And speaking of FrSky FASST compatible rx'es - it seems FrSky is releasing an end-pin version of their TFR6, the TFR6-A.

I haven't tried any of Coronas FASST compatible rx'es - at least not yet - so I cannot comment on their ability and reliability. The FrSkys have been rock solid, so if the Corona lineup are anything like the FrSkys they will also be excellent value!

*Disclaimer: I don't have any affiliation with neither FrSky or Corona - just a blogging end user of some of their products.
Posted by thomanie | Jun 13, 2012 @ 03:00 AM | 13,798 Views
FrSky has once again stepped up to the plate, listened to their customers, and taken another major step in providing decently priced alternatives to the brand name FASST receivers.

This time around FrSky has released the TFR8SB - a S.Bus capable, FASST compatible rx. Its basically a S.Bus capable version of their existing TFR8(S) FASST compatible receiver, although the circuitry seems to have undergone a revision as seen from the antenna positions. The major difference is that, in being a S.Bus capable rx, it's really only limited to the number of channels on your transmitter, and not the number of pins on the receiver. S.Bus systems wire differently than "old-school" receivers, as they fan out like a tree with branches, smaller branches, and leaves, with the rx being the trunk, and servos the leaves on the end of the trees branches - as opposed to each servo connected to a fixed set of parallel pins directly off the receiver.

The TFR8SB has already hit the street, and is available at HobbyKing for one. The really good news is that the TFR8SB is only a tad more expensive than its older, non S.Bus sibling, the TFR8S. With FrSkys FASST compatible TF-series receivers already having proven themselves as very reliable, and trustworthy - I see no reason why the TFR8SB should not follow suit. There's even a FrSky S.Bus servo about to be released, in case you don't want to shell big $$$ for brand name ones. The attached TFR8SB pic is shamelessly borrowed from the FrSky website.

Kudos to FrSky - well deserved. And please keep the good stuff coming!

Disclaimer: I have no affiliation with FrSky other than being a very satisfied user of their products...
Posted by thomanie | Jun 03, 2012 @ 02:53 AM | 12,295 Views
The NATO TigerMeet is currently underway at Ørland MAS in Norway. Saturday June 2nd the RNoAF hosted the 2012 TigerMeet Airshow as part of their 100-years of airpower anniversary.

The list of participating aircraft was quite extensive - including F16s, F18s, Rafales, JAS Gripens, Tornados, KC135, P3 Orion, AWACS, a Catalina, 2x DH Vampires, Safir, Safaris. Rotorheads could also drool over a Sea King, NH90, or a Super Puma.

Friday featured SpottersDay where the aviation nerds could get real close on the action, while saturday was open to the general public.

Altough the weather wasn't too nice, there were lots of people, and the brave aviators put on a good show.

*** UPDATE ***
Short Airforce video from the meet
Posted by thomanie | May 31, 2012 @ 03:19 PM | 12,235 Views
I had the privilege of flying as an instructor at the Norwegian Airsports Federation glider instructor bootcamp last weekend. We had an oval weekend with 3 days of flying - and lots(!) of fun. With temperatures reaching an unusually high 28C for late May, we had some pretty decent thermal activity.

Nope - it's got nothing to do with modelling, apart from being airplanes...

Enjoy!
Posted by thomanie | May 02, 2012 @ 02:23 PM | 16,921 Views
Introduction
I needed a set of rotating retracts for a 65" scratch built P40 I'm building over in the Scale Electrics section - and preferably electric retracts. The RCLander 90-120 size rotating electric retracts caught my attention.

Rotational retract choices
At time of purchase there weren't really a lot of choices available, although this situation has improved somewhat over the last year since I bought mine. Wanting electric retracts, to avoid any air leaks too often accompanying pneumatic retracts, limited my choices even further.

Robarts weren't electric, I was not keen on doing a electric modification myself. Add to that some mixed reports, and they were quickly ruled out. ESM had an electric set (their v1) which was out of the question with their +30 sec cycle time. There was also some expensive Sierra penumatics, as well as electric Lados and Gizendanners. And there was the E-flite 25-46 size 100 degree rotating ones, for thier new 50 sized Corsair. Needing everything else for the airframe too, I had to put a cap on the budget. I decided on the RCLanders as they were just north of 100 USD including oleos, and put my order in.

Packaging
The retracts arrived in a transparent plastic box, along with its set of oleos and wheels. They didn't look too bad for the price.

First inspection and cycles
First inspection showed some slop. Not too much, but there was some. Both forward and aft, as well as sideways. At the axle I had about 10mm or 3/8" slop. In no...Continue Reading
Posted by thomanie | Mar 15, 2012 @ 07:27 AM | 17,471 Views
Here's the latest off the building board - a 1/7th scale P-40E Aleutian Tiger

The model is built from Mark Rittinger 42" P-40 plans, enlarged to 156% to produce a 1/7th scale model with a 65" wingspan. I tweaked the original fuselage construction slightly, and designed my own built up wing with retracts and flaps. I believe you could build her per plans, and she'd work equally well.

Specs and gear used:
65" WS
Turnigy 50-65A 400kV outrunner
HobbyKing SS Series 90-100A BL ESC
TGS 16x8E 3-blade prop
Turnigy 3S 5000mAh x2 in series for 6S
6 channel control, incl retracts and flaps
6x HobbyKing standard servos (2 aileron, 2 flaps, rudder, elevator)
FrSky 7ch FASST compatible rx
4" alu spinner

She still hasn't flown, but will as soon as weather and schedule permits.

Enjoy!
Posted by thomanie | Feb 27, 2012 @ 04:46 PM | 19,112 Views
FrSky TFR4-B
I've already done mini-reviews of the recently released additions to FrSkys TF-lineup of receivers, the FrSky TFR6 and its smaller brother TFR4. Next up is the TFR4s twin - the FrSky TFR4-B.

FASST compatible?
The TFR4-B is a 4ch FASST compatible receiver. It's not a genuine FASST receiver, but works nicely with both Futaba FASST air and surface system transmitters. FrSky adressed two slight concerns raised by users with its twin TFR4
  • TFR4-B ditched the plastic casing for even lighter weight
  • TFR4-B has a horizontal pin configuration
For my testing I've again used my trusted 10C. I still don't have a Futaba surface system to test with, nor am I into multicopters or telemetry, so I haven't tested the surface capabilities nor CPPM/PWM output. CPPM/PWM output from the receiver is essential for automated flight control circuitry used in multicopters, and can be put to good use in some telemetry solutions.

Size, weight and pricing
The TFR4-B is physically very similar to its twin TFR4, both being smaller than the TFR6 - by a hair. At only 4g it weighs a staggering 30% less than its hard-cased twin TFR4. I must admit at these weights my kitchen scale isn't very precise. However, the actual weght reduction probably isn't noticeable unless you're into ultra lightweight stuff. Its small physical size makes the TFR4-B ideal for smaller models. Added bonus is it being a full-range receiver. With the pins horizontal off the rx, not vertical like the non-B version,...Continue Reading