Turbo Timber 2M SWS – Part Six – Flying!

Turbo Timber 2M SWS – Part Six

With the Turbo Timber ready to fly I made an exception to my usual standard for maiden flying weather and  headed to the field on an exceptionally warm (72F in early March in Indiana) and rather windy day with solid 10-15mph winds with occasional gusts to probably 20-25.

I put in two flights, with each flight lasting around 7 minutes of actual wheels up air time.  I was very happy to see that both flights ended with batteries at above 60%!  Both flights were using my SMC 5900 HV packs.  I used a mix of throttle settings and manuevers with a fair amount of IMAC inspired aerobatics.  Only one real full throttle pull straight up and a couple of hover/prop hangs just to see how it handled it.  The plane did fine but my reflexes were a bit rusty with the gusty winds making things a bit more challenging.

My first impressions is that she is fairly fast.  The plane looks and feels very slick.  She picks up speed quickly and seems most comfortable to fly at a slightly higher pace than just your average trainer/high wing STOL in my experience.  She will slow down quite nicely with some flaps applied.  I’ll get a better feel for that when I can fly minus the winds at some future point.  Maintaining a comfortable speed at around 60% throttle seems to be a very economical cruise mode from what I can see in telemetry… drawing 10-30A which would result in 10 minute plus flight times if maintained!   This speed doesn’t look “slow”, nor does the plane feel sluggish if your just maintaining level flight and making standard turns.  I will add my GPS module soon and get some speed readings. She fairly jumps when you hit the throttle and is quite quick to all appearances.  Pulling straight up and rolling in throttle results in a nice steady vertical line if that is what you want.

After the first 7 minute flight, I was amazed to see my meter report a bit over 60% of capacity still in the batteries.  My timer was set for 5:30 but I flew past it, expecting the battery to end up closer to 25-30% but now I will push it up to 6:30 and try my 5300mah HV packs to see where the charge state ends on those.  Telemetry reported peak draws at 70 amps for one flight and 75 on the other while in flight so the ESC should be capable of handling that with ease. On the ground, restrained you can hit 90 or a bit more. That’s running a Xoar 15×8 E Prop which is extremely similar in shape to the supplied wood prop.  I wouldn’t be suprised if the supplied is also made by Xoar, as I understand they are a huge manufacturer in the field.

With those peak currents the ESC is reporting as high as 1400 watts and over 9000 rpm. Considering the motor is spec’d for 900W max, I wouldn’t want to hold that for a long period, but the climb rate is quite impressive so not sure why you would need to.  I see one near vertical climb I made which netted 290ft of vertical climb in 9 seconds…  so holding that for another 20 seconds is going to put you at 1000 feet and the airplane is going to be looking pretty small!  With any moderation at all, I don’t think the motor or ESC is going to have any heating issues… but we’ll see when the temps move from 72F or so to 90F here in a few months!

The receiver reported voltage stayed between 7.5 and 7.32 through both flights with the BEC temp running from 85-130F so I am happy to report that the BEC isn’t showing any strain in spite of a lack of any airflow in the area where the ESC is mounted.  I may eventually add some exit area just to encourage some modicum of air passing the ESC and maybe I’ll remount the ESC so the heat sink won’t be wrapped in hook and loop material.  I don’t understand wrapping a blanket around that to hold it when it has mounting tabs built in! 

With only 35 or so frame losses during the flying portions of each flight, the receiver seems to be getting good signal… though it occurs to me I have an extra remote or two laying around I might add just so when I do some glider tows to extreme altitude later on, I have have confidence in my control of the airplane.  Though there are two antennas, the 8360 is just one receiver so having a remote receiver I can mount elsewhere in the plane seems like cheap insurance.

Mental notes from the first flight include:

  • Possibly adding a bit more down elevator to the flap mix.
  • Bringing down the Elevator rates.  Mid rate had enough throw to cause a snap… something I normally reserve for a high rate setting.
  • Adding a remote receiver for “signal insurance”
  • Adding a GPS module (which I already own) to get some readouts on speed

That’s what I can report for now. So far she is flying well and I am enjoying it. Lots more fun and experimentation with crow, full span flaps, reverse thrust braking etc… coming during future flights!

Turbo Timber 2M SWS Part Five – Final Tweaks

Turbo Timber 2M SWS – Part Five

Having run through the majority of my checklist, I had a just a couple items left to consider. 

Originally, I had thought about making some servo/linkage covers for the TT, but on reflection I didn’t really think that was really necessary in this case.  With it being a high wing and keeping the wings somewhat cushioned from handling issues by storing them in wing bags, I am not really concerned about handling or field damage (on a low wing, sometimes the linkages would touch the ground during a less than optimal landing but not on this bird!).  Also, with the TT, I’m not expecting a lot of high speed flying so wind resistance or aerodynamic considerations are not really a factor so we will just check that box off and move on.

The next item was to add a glider tow release to the airplane.  I’ve had something similar on several planes and have a good handle on the proper placement and functionality needed.  The tow release is actually not the way you want to detach the glider from the tow plane, its simply an extra safety measure allowing the tow pilot another option in the case that the glider causes issues… release failure, erratic flight, or whatever…  and there is a need to quickly remove the connection between the two craft.

Placing the release toward the trailing edge of the wing is typically a good compromise.  Close enough to the CG of the plane to minimize the effect of the tow on the flight of the tow plane with plenty of avaialble structure to mount to and a clear path for the tow line to avoid any likely entanglement since the towed plane is typically above and behind the tow plane.  I had a nice tow release I pulled from another aircraft when I sold it, so all I had to do was create a mounting plate and assign a switch with appropriate endpoints and I was pretty much in business.  As I’ve done on other aircraft, I notched the trailing edge at the center of the wing to fit around the release.  Here are some pics of the installation.

I built the whole release mechanism out on a board cut to size to fit the bulkhead top to bottom brace dimensions and then glued and screwed it in…  Here is a shot of that installation.

Here is what it looks like with the wings notched to fit around the release.  I’ll clean up the notches a bit… maybe harden them with some glue on the exposed wood and then paint white or cover…

Another couple of items on my list are items for another day.  Having a camera mount would be nice to grab some video, but I’m still debating location(s) and how to attach the mount(s).  I may work on a design to use the glider tow release as one mounting point…  just don’t drop it by mistake!  Another option is in cockpit but the windscreen is curved and not perfectly transparent so likely I’ll look at something underneath instead… probably attached to the landing gear in some way.  But, I’m not in a big hurry for that.  Likewise, I’d like to put floats on the TT, but I have some time for that and I haven’t decided if I can adapt some floats I have or if I’ll dole out for the standard option available from E-Flite.  Likewise, I want to paint a prop with some matching colors to the scheme on the airplane but for now, my standard Xoar 15×8 is looking pretty nice so that can wait for another day as well.

Just as I thought I was going to concede that I was ready to fly this bird, I ran into a minor issue.  I was having trouble getting the prop nut tight enough to feel safe that the prop and spinner were going to stay attached… especially if I employ reverse thrust… without the prop spinning against the spinner backplate.  With a cowled installation like this, there just isn’t access to the motor to get another gripping point.  After some discussion online, I was reminded of an old trick I had employed before and had forgotten.  Taking some sandpaper and cutting out a couple discs and then gluing them back to back I created a very high friction washer.  Sandwiching this between the prop and backplate stopped the slippage and  allowed for a nice snug connection.

Of course, this was NOT the end of the story.  As soon as I had the prop and spinner properly attached, I ran up the motor and immediately noticed that the tip of the spinner had a very small “wobble”.  I verified that the motor shaft was running true so it had to be something in the spinner itself.  I have no idea where this went wrong… maybe in trying to tighten and hold the spinner, I damaged it/warped the backplate… maybe in manufaturing… whatever.  I found an appropriate location for the spinner… (I have several trashcans in my shop) and started looking for a replacement. 

I had considered replacing the spinner early on with a slotted spinner in order to increase airflow over the motor and so this was just an opportunity to check off that item.  I quickly found a couple of vendors out there for a nice spinner that promotes air flow and in a few days I had a nice spinner from Gator RC in my hands.  That spinner (57mm/2.25″ diameter) turned out to be a perfect fit, with the metal backplate fitting the motor shaft perfectly as well as eliminating the slipping issue AND no more wobble!

All that is left at this point is to check balance and throws and get a good day to get in the first flight or two.  Eventually, I would like to consolidate my various rate switches (I always start out with Ail/Elev/Rudder throws and expo settings on individual switches) but for now I want the flexibility to switch each individually and see what setting best matches the way I want the airplane to fly.  I’ll try to post some pics and report on how that goes but I have every reason to expect it is going to be a great flying airplane.  Here’s to a successful maiden flight!

Turbo Timber 2M SWS Part Four – Radio setup, modifications and repairs??

Turbo Timber 2M SWS – Part Four

There were a few things I felt I just needed to change right out of the box with the new Turbo Timber SWS.

My first thought was that I wanted to take advantage of the electronics provided in this newest iteration of the Turbo Timber.  To that end, I started down a long list of adjustments I wanted to make.

First, I did a bit of programming on my radio.  Starting with a template I created from the program I had based on the Grand Tundra, I checked all the settings were adjusted per the manual.  Using the template gave me the voice prompts and standard switch locations I would normally use without having to manually reenter them.

 I always like to have my ailerons on separate channels when I have the channels available but in this case I also wanted to do it to allow for a bit of crow mixing.  To allow for this, I adjusted my wing type  to 2 aileron, 1 flap.  I didn’t bother to split the flaps as they are not hinged to deflect upwards anyway so there is not much to gain.  One accomplished, I removed thy Y harness and wired the ailerons each to their own channel making sure to get the correct aileron in the appropriately labeled channel.

Next up, I wanted to enable the reversing function of the ESC.  I attempted to enable this using the ESC telemetry programming screen that normally is available as the last telemetry screen you will find if you scroll through all the Telemetry screen with the airplane and radio powered up… but to no avail.  The screen just wasn’t there!  After some troubleshooting, including rebinding, upgrading my radio to the latest software, etc… I realized that the ESC was loaded with very old code.  I was a bit iritated with this, as that particular function has been out for a very long time and I would have thought by now, Horizon would have made sure all the shipping product had that code already loaded.  But apparently not.

I then pulled out my trusty ESC programmer and connected with my laptop and updated to the latest version.  Following a power cycle, “bingo” the programming screen was now available!  I adjusted the braking method to allow reverse with the laptop and programming box but inevitably realized after disconnecting and packing it away… that there was another setting or two I wanted to adjust!  For one, I wanted to move the reversing function to a higher channel to eliminate conflicts with other radio functions I might want to program on the lower channels.

No problem, I simply went in with the radio and scrolled across to the ESC programming screen and entered the menu via the indicated stick motions… or maybe not.  After a couple of attempts, I recalled that you need full channel output to get this to work so I adjuted my switches to max throw and again, things were looking up.

As I was scrolling through the options, I realized there were a few other things I wanted to adjust.  So while I was in the screen I adjusted the brake/reversing function to channel 10 as planned,  but also disabled the auto cell count function and disabled the voltage cutoff feature.  If you think that’s a bit unusual, let me give you the brief logic.  First, I like to run the new HV Lipo batteries from SMC and I have seen ESCs that will mistake an HV 6S for a 7S and if the cutoff feature is enabled, this can lead to a cutoff occuring very early in the flight.  This can be dangerous, especially to the airplane’s health!  Throttle being cut just after takeoff is not ideal. 

Second, if I have to make a choice between damaging my batteries due to overdischarging them but managing to eek out enough power to get my airplane down safely… or having the ESC protect my $90 battery at the expense of trashing my $800 airplane… I think you can guess what I pick.

I also set the BEC output to 7.4V instead of the default 6.0V.  The servos in this bird are high voltage and the vast majority of Spektrum receivers (including the 8360T provided) are capable of working with a wide range of voltage inputs.  With this equipment I would always favor a higher voltage setup.  For reference, volts times amps equal watts (which measures power).  So you can provide the same amount of power supplying a higher voltage with less current draw and high current often exposes any flaws in the electrical system.  For instance, many connectors can easily handle a higher voltage than we require but when they have to pass higher current they begin to heat up and the excess heat causes failures.  So as strange as it might sound, if the electronics are designed for it, I believe using higher voltage is easier on the system.  High current causes problems that an appropriately high voltage does not.  Also pulling less current to do the same work means longer flight times, assuming the extra battery weight to get the higher voltage isn’t prohibitive.

On a related note; I am always torn between using separate flight pack batteries (usually a 2S LiPo) or letting the ESC provide the power on 6S powered aircraft.  At the typical size/weight range of a 6S bird, you are approaching airplanes that can typically handle the excess weight of a separate battery pack to provide power to the servos and radio gear without noticable effect on wing loading.   Also, separating this function relieves some of the load on the ESC as well as providing a level of fault tolerance if the ESC should fail or the main fligsht pack gets disconnected, etc…  That’s the positives of using separate receiver packs.  On the downside, it adds weight to the airplane, adds expense to the setup (additional packs, switches, etc…) and adds a bit of complication which weighs in against reliability.  Complicated things just fail more often.  When I move up to higher cell counts I default to a seperate power pack (or two) but 6S is right on the border for this setup, in my mind anyway.  For the TT SWS I do not plan on a separate pack, so setting the ESC to high voltage is what I believe is the best option.

Once finished, I moved on to wiring up my multi-connectors to make the wings easier to attach and detach along with cleaning up a bit of wiring.  This presented a bit more of a problem than I anticipated.  First, I made the connections between the three servo wires exiting the bottom of the wing and then wired up the other side of the multi-connector to the receiver.  Doing a trial fit I realized that there is a bulkhead that touches the bottom of the wing in between the wire for the lighting and the wires for the servos.  I thought about notching the bulkhead but I didn’t like that idea so I went to plan B and pulled the lighting wire back up to the flap servo hatch and then fished it down along side the servo wires to make them all emerge at the same exit.  Here’s a couple of pics of the process.

Here’s the original routing with my multiconnect already plugged into the flap and aiileron wires.

 

I used a wire to snag the lighting wire from the front portion of the wing back into the flap servo pocket.  I then pulled the servo connector end of the wire back to this point.

Following that I looped the wire through large nut (a convenient heavy weight to help with the process) and lowered and shook the wing to get the wire to drop down to where I could snag it and bring it out to the wing root.

 

At this point I removed the nut and fed the wire through the same hole in the bottom of the wing that the servo wires emerge from.  Problem solved.

Once I got those connectors in place, I remembered a problem I had with the smaller Tundra’s and which will be amplified by the size in this case.  That is, when assembling the wings and plugging in the wiring, you must hold the wing up out of the way and even with only two connections to make, this can be a bit tedious… especially if there is wind trying to grab that big wing and throw it on the ground!  I’d seen a few approaches to fix the problem and I liked the idea of attaching the connectors inside the airplane so that I could connect each connector with one hand.  After a few measurements, I created a bracket that holds the connectors in place in the airplane and can be disassembled if needed for any sort of repair.  I used my trusty 3D printer to create this bracket and used some canopy glue (which can be removed in a pinch but holds plenty tight for my purposes) to help hold it in place.  Here’s a pic of the installation.

At this point, I recalled that I wanted to have a way to switch the landing lights (these are located in the cowl) off and on.  I had this on my Grand Tundra, and enjoyed it.  So I moved on to connecting up a small in-line switch (the PERS v2 from Hansen Hobbies) to allow me to switch that output.  After inserting the PERS, I noticed the landing lights were flickering and soon one and then the other winked out.

To me that seemed… to use a technical term… BAD!  I pulled the PERS back out and connected back to the standard wiring… no go.  I then got a separate battery… nope.  OK, so what the heck… then I recalled that ESC voltage setting… 7.4V… instead of 6… hmmm.  I guess the LED circuit wasn’t designed for the higher voltage… even though every other component of the airplane is!  Even though every other LED seems fine!  Yes, Horizon Hobby didn’t tell me to do that… or that I even could.  But, I still think they could have done better on this one.   

It was a bit of a job to replace the LEDs… They were glued in very well.  I ended up crushing them with pliers to break them up and then drilled out the remains before gluing in replacements.  With an appropriate resistor in line with each to limit current appropriately at the higher voltage, things brightened up nicely and putting the switch in line was easily accomplished without issue.

At this point, I was getting pretty close to finishing up with all of my setup for the TT SWS.  Next time, I’ll try to wrap up this series with my final few items before she has to sit in corner and wait for some nice weather.

Turbo Timber 2M SWS Part Three – Assembly and modifications

Turbo Timber 2M SWS – Part Three

Assembly has begun after a good read through of the manual.  I am proceeding in an order that does NOT follow the manual but just as my fancy strikes me and the time available allows.  So here we go.

The first step I tackled was assembly and install of the landing gear.  This went pretty much according to plan until I went to mount the gear on the bottom of the airplane.  At that point I noticed that the landing gear cover that sits over the landing gear and acts as a large washer could not sit flat… it seemed to be to thick/long to fit.  This shows the gap.

Then I figured out that there was a layer of ply that apparently is held in with double sided tape…  very strongly in my example… still attached to that cover!  Once I realized it was there I pried the plate loose and everything fell into place.  The manual doesn’t mention removal of the landing gear cover at all, it just jumps to mounting the landing gear and attaching the cover.  Here is the cover and the excess plate you want to remove.  I marked the front as I was working as the body of the plane is tapering gently at the point where this mounts.

The final part of the landing gear is attaching the “fairing” to the outside surface of the landing gear.  The manual calls for simply gluing this in place but I’ve seen several examples already of those disappearing during the first flight or two so I was wondering how well this was going to work.  So the first thing I did was to glue it on as directed and give it time to set up.  It lasted about 8 hours until I accidently contacted it during a later work session before I knocked one of them off!  So I reapplied the glue and clamped and let set once more.  Then I went back and drilled and tapped the landing gear (on each side) for a single 3mm bolt.  I put a washer undel the head of the screw and after tightening added a nut on the reverse side just as a jam or lock nut.  I am hoping that this will help the fairing stay in place.

Another task I took on early on was to mount the Propeller Adapter to the motor.  As I was working on this I checked the bolts holding the motor box to the front of the firewall as well as those holding the X-mount to the motor box.  I noticed several needed a bit of tightening so I took the time to pull each and put some lock tight on before a final snug up.

 

Another step in the build manual was applying velcro in the battery tray and setting up the battery straps.  I varied from the method in the manual and went with some shelf liner and a couple of straps but the method outlined in the manual will work as well.

Next, I mounted the cowl.  With predrilled holes this was pretty painless.  Of course I decided to add the additional cooling scoop which requires a bit more modeling skills than most of the build and risks your Cowl if you cut in the wrong place… but it went on easily and I’m always a fan of better cooling to keep my expensive electronics working well.  I have my doubts about the glue holding this on, so I may revisit the attachment a bit later.

Finally, I turn to assembly of the tail section of the airplane.  You put the horizontal in place and then slot the vertical down into the top of the plane… part of which extends through the horizontal, creating a solid connection.  long studs extend through to the bottom of the airplane.  It was a bit difficult to work the vertical into place, but I eventually slotted it in with a little wiggling and a small amount of profanity.  I actually like how tightly it fits and while my first instinct was to add some glue, I’m resisting that idea with the thought that removal of the tail surfaces is possible in the future should the need ever arise.  Also, have a 5.5mm nut driver or deep well socket handy for this part as the nuts that hold all this together go down in a bit of a hole!

There is not a lot more to talk about that falls into the category of assembly.  Pretty much all the other steps in the manual were self explanatory and went without any real need for modification or comment.

Next, I’ll tackle all the electronics and radio setup work I’ve been doing.

Turbo Timber 2M SWS – Part Two (Inspection and Possible Modifications)

Turbo Timber 2M SWS – Part 2

As I was ordering, unboxing and just enjoying looking over the new addition to the fleet, I was reading and thinking and starting to make lists of possible updates, upgrades, modifications and accessories that I wanted/needed for the new airframe.

Its pretty cold and windy here in Indiana in the wintertime (Jan-Feb) so my available hobby time was in the shop or attending swap meets when possible.  Often I was going to the swap meets and selling stuff to pay for the TT SWS!

While I was doing all that I started compiling a list of things to consider changing/adding as I assembled the airplane.  Some came from reading about it on line, some from my experience with similar airplanes and what I knew about this new one and some came up during my unpacking, inspection and assembly.  So here is my list, in no particular order along with a few notes.

  1. How to attach the landing gear “spats” to the aluminum gear.  – I’ve already seen videos where they fell off on the first flight or landing or both.  I don’t think glue is going to handle this by itself.
  2. Install a light switch? – I had one in line with the landing lights on my Grand Tundra and it was nice to be able to switch those off and on separate from all the other lights.
  3. Crow?  – If I separate the two ailerons onto individual channels I could have full span flaps and crow if I wanted them… there’s some other mixes this enables as well.  Of course this plane doesn’t need any of that… but I could.
  4. Replace the ugly yellow wing bolts. – The yellow bolts just stick out like a sore thumb against the pristine white covering.  Black would look more in keeping with the color scheme as it exists so if I don’t have some whiter nylon bolts available I can go that way.
  5. The wood prop that it comes with is labeled 15×8 and looks remarkable like, other than being a tad shorter and not as shiny a finish, a Xoar E prop.  I happen to have a Xoar 15×8 in the drawer brand new so I could swap and maybe paint the stock prop to look nicer.
  6. Replace the wheels/tires.  – I’ve seen complaints on the tires being to hard but I’m not a fan of the inflatable types on this size/type of plane because they are hugely heavier than these.  If I have any other options laying around or if the new tires are really hard I can look around for a good light replacement.
  7. Servo Covers  – I’ve had a plane or two that had little 1/4 of an egg shaped covers or cowlings that shield the servo arm/linkage.  They look nice and are nicely aerodynamic.  I also like the protection they give the linkage/servo when the plane is in transit…
  8. Floats – I’v sure the TT makes a great float plane.  I love flying on floats and I have 3 or 4 sets around the house in dusty crannies… If I can find some that are a good fit I might adapt those.  Could always spring for new ones too…
  9. Add lights (interior).  – I would like to light this thing up internally to make it easier to fly at dusk and beyond.  
  10. Multi-connectors for the wings.  – I have some hanging around already and have the ability to tools to make more.  I know how much easier it is to connect/diconnect the wings when you only have one or two keyed connectors to plug in.
  11.  Spinner  – I had another plane recently that used a slotted spinner to increase airflow to the motor and love the idea of keeping the motor as cool as possible for long life and good performance.  Need to see where I can get one and at what price.
  12. Wing bags  – There are no wing bags with the airplane and a good set is really needed to keep things looking and functioning like new for a long period.  I need to see what I have around and if not, will probably order something.
  13. Identification  – Just a reminder to make sure I add my FAA registration as well as my AMA number.  Don’t want to run afoul of any regulations that will keep me from focusing on having fun when I’m out to fly.
  14. Personalization  – I pretty much always do something to separate my bird from the flock and this one will be no different.  Intially I’m thinking of stripping anything that is an actual decal and then add some stripes/pin striping or something similar made from vinyl or RC covering rather than water slides.
  15. Camera Mount  – Sooner or later I will want to put a GoPro or two on the plane and get some video so need to start planning location and method of attachment.
  16. Clean and Wax  – I have found that, especially on foamies but on covered aircraft a well, if you give the plane a good coat of wax… something like a good map on floor wax… less dirt clings to the airplane and it is easier to keep clean.
  17. Glider Tow  – Towing gliders is great fun and this plane looks like it would server very well for this.  I just need to figure out a mounting plate I can put near the trailing edge of the wing (top) and get that in place and controllable from a switch.

There are bound to be other things that pop up as I walk through the assembly so I’ll be back in the next part to talk about my assembly process as it proceeds and also comment on the above items as I address them or decide not to… as well as resolving any of those discovered issues.

 

 

Turbo Timber 2M SWS – Part One (Buying and Unboxing)

Turbo Timber 2M SWS – P1

I have long been a fan of versatility in an airplane.  I love aircraft that have a wide flight envelope, can fly for a good while if you keep out of the throttle, can tow a glider, haul a payload, fly off grass, snow and/or water, and look pretty good doing it!  For that reason, I have had many planes that to some extent fit that description.  I had my Telemaster 40 rigged with a bomb drop, glider tow release, floats, etc… over the course of serveral years and had several of the Timber line of aircraft, as well as the Grand Tundra and some others…  The Grand Tundra was my everyday airplane filling that role for a good while, but it was never a partiuclarly attractive aircraft and it is foam… I know a lot of folks thing that is great, claim they are easier to repair, etc… but I am in the opposite camp.  I would always prefer to work on a wood airplane.  Once its broken/bent/scraped and battered, I find it much harder to get a foam plane back in shape.  I know partly that is because I hate the sanding and finishing work it takes to make a foam plane look good.  Without a huge amount of work, a foam plane just looks like… well… foam… and once you compress it and tear it… lots of work involved to get it back looking decent… flying maybe but no exactly straight or pretty without a lot more work than I want to do.

So, when E-Flite dropped the Turbo Timber 2.0 SWS it caught my attention.  It is almost the perfect plane, on paper. 

I prefer Electric power to anything else these days (check).  I love anything that uses 3S, 6S, 8S or 12S as I have the appropriate batteries for most of these already in hand.  6S aircraft in particular often fall into a sweet spot of large enough to fly well, easy to haul and inexpensive to operate with high quality 6S batteries being easy to get at good prices these day.

I have been using more and more of the Spektrum electronics in my planes.  The ESCs have all the features I want, including some useful telemetry when combined with the Spektrum receivers I’m already choosing.  They also have some good servo lines and what seem to be good motors and this has all of that as part of the package.

Wood construction covered in good quality iron on covering with a nicely visible scheme.  This means the airplane just looks better than most foamies ever will.  Plus a wood airplane is often just stiffer with less material involved so ends up holding its shape better under G loads… at least that is what I believe.

Thus began my determination to get one…  Several planes went up for sale, along with assundry other items laying about the shop… bye-bye Grand Tundra and hello TT SWS

First of all, I know some folks are going to say… “The price is to high!”  and I get that.  But, my feeling is… aside from I’m getting old and everything seems high to me… the price actually seems very fair.  Especially when you buy the ARF like I did.  The electronics that they chose in this airplane seem to be pretty high end.  The Spektrum line of ESCs, Servos and Motors all seem to be good quality.  My experience so far with their ESCs has been nothing but positive and I have several.  I especially enjoy the programmability right from my transmitter and the available telemetry is something I consider to be a must in an electric aircraft.  You have to combine them with the compatible receivers to get all of this but I would have bought that or a very similar receiver anyway!   I will point out that I do not have, nor want the Spektrum batteries and chargers and don’t see the value to justify the cost of that part of the Spektrum product line.  I have done a lot of study on LiPo batteries and I have a couple of favorite brands I purchase from at a much lower price and better performance than anything Spektrum has produced so I don’t expect that to change anytime soon.  The servos have great specs for the price and while I’ve only had a few, so far so good.  I don’t think I’ve owned any of their motors yet, but they appear to be well built and I’ve not seen anything that would give me pause… so the ARF comes with equipment I would likely chose for myself so all in all the bundle makes sense to me financially.

So a few days ago I figured out how to get a 10% off coupon which aligned well with the balance in my “RC fund” as a result of some sales at a couple of swap meets and Facebook marketplace adds and the order was placed.  I also got lucky and caught it in stock for what I understand was about a one day window on Tower Hobbies web site.  I think this was the second shipment they received and the ARFs didn’t last long!  I settled in to wait the predicted 2 weeks or so for free shipping and started looking for any discussion groups or video reviews that I hadn’t already read.  That lasted for about a day when suddenly I got an update saying it was shipped via Fedex!  Being only 100 or so miles from Champaign, IL where Tower is based has some advantages and the predicted arrival was 1 day!  It got confusing for a bit as Fedex seemed to decide it hadn’t shipped after all then changed the expected arrival day two or three times until finally it actually showed up after only 2 work days!  Yahoo!

I was a bit concerned when I saw the box had a corner torn out…

It turned out the outer corrugated box had done its job and protected the contents and even the inner box with all the pretty graphics was in like new condition! 

Work got in the way and it took me the better part of 2 days to unpack the box and another to unwrap all the parts and lay them out on the bench.  It may have taken a few hours just to clean the bench and make room to do this but much of that was done while I attended to some conference calls with my headset on.  Having a new airplane all layed out on the table right behind you can be distracting but I managed to at least do my cleaning chores and some unwrapping while paying sufficient attention so a few business calls!

Here’s some pics of that process to give you some idea how well the packaging worked out… Everything seems intact with nothing beyond a scuff or two… that’s about as good as can be expected for a shipment from (I presume) China all the way to the midwest US.

Just taking off the lid…

Wings out and down to the tail sections… everything taped down to minimize shifting/scuffing.

Tires, LG, all the hardware… bags in bags to keep things separated.

Notice the wings have guards over the servo linkages to keep those from digging into anything else… nice.

Front and back of fuse are embedded in foam to keep it away from box sides…

With tail pieces removed we find the cowl (fiberglass) nicely protected/wrapped and secured in place.

After removing the cowl and body… down to the bototm of the box where we find the prop and wing tube.  Prop looks like a copy of a Xoar (or maybe made by them??)  Finish on the prop is not quite up to Xoar standards and the length of the blades is a few mm short of my actual Xoar but the basic shape and profile is very close.

All the parts on the table… awaiting unwrapping.

Now free of all the plastic wrap… not a lot of parts.  If I was in a rush maybe a 2-4 hours and I could have it done??  But I am being meticulous on this one so it will take much longer.

I’ll break this up at this point and start on my next steps with the following disclaimer:

I’ve seen enough on the lists and video reviews and such that I am confident in saying that you could easily (if you have much experience at all) just go through the directions provided in a few hours and come out the other side with a perfectly serviceable and good flying, completely stock, Timber 2.0 SWS…. but that is just not how I roll!  I’m not big on doing modifications just to do them, but I like to do what I think will result in the airplane having a long life… no silly crashes because someone didn’t tighten a bolt… and I want it to be just a little distinct from every other similar airplane at the field.  I also want to do what I can to make it run efficiently with adequate power and flight time, and as easy to transport and assemble as I can without to much effort.  So next up will be an inspection and a list of what I see that I might check/change or modify to make this airplane uniquely mine and to help make it last (I hope).  Some other setup/changes will be to suit my intended purpose(s) without getting to drastic.  And I’ll be picky and try to fix anything I see that jumps out at me as being “not to my standard”.

Fully 3D Printed Airplane – Part 5: Pit accident, reprint and removable wing

Well “Wolf #2” fell prey to another pilot’s RC airplane that got away from its owner and chewed the tail off of my Wolf. 

So I immediately started planning for Wolf #3!

A couple things I learned from Wolf #2.

  1. One bit of fine print I had never noticed in my builds of Wolf 1 and 2 was the recommendation for differential aileron.  Rudder is often used to make up for adverse yaw but often the best solution (short of a different airfoil) is to implement differential aileron.    This lead me to the discovery that once implemented I no longer had the need for rudder to get turns absent the adverse yaw I had experienced in previous flights.  
  2. After flying with a 2200 3s and a 1350 3s, I soon realized the 1350 provided for better performance with more than adequate flight times.  I finally tested an even smaller battery pushed forward to maintain proper balance led to even better glide characteristics and less need to maintain speed.  I settled on an 850mah for adequate flight time combined with just enough weight to get a proper balance.

So with all that in mind, I decided I could afford to drop the rudder modifications.  Along with the lighter battery this meant I saved enough weight that I could make modifications to allow for a removable wing without worrying about making her to heavy.  I had found having the wing permanently attached made the Wolf unnecessarily difficult to transport and more easily damaged than necessary so I planned to remedy that.

In order to accomplish this I had to create some new strut attachment brackets and provide for some reinforcemment, both in the wing and where it mates to the top of the fuselage.to make me comfortable that the wing would stay attached., to be sure the wing would stay attached!  For the struts it was just a matter of creating some small blocks to attach to the body and wing with an inset to capture a nut.  That looks something like this.

Wing end

And fuselage end

Then I used the Cura Slicer program to add a support blocker to the part during the slicing process.  By doing this,  I could then add an ioption to modify the settings for the overlap that allows for adjusting the infill as well as the number of walls.  By doing this I was able to create areas in the wing and on the top several millimeters of the wing saddle area that are much more dense/strong.  This accomodates the threaded insert installation (melting those into the saddle area) as well as increased support for the bolt head and washer to hold the wing securely.

You can see the denser area as a darker triangle in the wing…

and on the top of the fuselage

The result of this is something a bit easier to transport

The sharp eyed (pretty much anyone who can see color… at all) may have noticed some color variations in the new version of the Wolf.  This was another option I went for when I had to reprint.  I am not a big fan of painting/sanding etc… so to make the airplane highly visible and keep from having to do any painting I printed with pause commands inserted at carefully calculated layer levels to allow me to change filament color and create the banding effect you see.

I have only had 3 or 4 flights on the latest iteration of this aircraft but so far it seems to be structurally sound and flies pretty well.  With it getting cold here in the mid-west part of the US, this one will be going on the shelf for a while but I’m looking forward to more time with it in the air this spring.

 

1.2M P47… The latest addition

E-Flite has been updating a number of their existing warbirds in this size class to include the latest round of upgraded electronics, including 3 and 4S capable power systems, upgraded digital servos and often a livery change and/or some tweeks in response to past user feedback.

It was inevitable that they would eventually get around to one that I could not resist and of course the the P47 is the one for me.  I consider it the ultimate WWII aircraft.  Showcasing all that allowed America to come out on top in that epic struggle, it was powerful, fast, tough and reliable, heavily armed and armored and we made a bunch of them!  (15,000+ I believe)  Many were assisted down the assembly line by my Grandfather in Evansville, Indiana!  How can I not love the Thunderbolt?

P-47 Razorback 1.2m BNF Basic with AS3X & SAFE Select

So, as soon as they started rolling out the newest version, I put one on order with my local hobby store.

After about 10 flights with mine.  Here is my list of what I really like and dislike about the new bird.

Good:

The new electronics are great.

Upgrading to a 4 cell power setup gives the bird the power it needs to perform like a warbird

The new SMART ESC and AS3X receiver allows for plenty of data to keep an eye on battery usage, temperature, etc… to insure she continues to fly well. 

The servo upgrades seem to work with precision and the plane just overall flys nicely as a result.

Weight.

The plane is actually pretty light, especially considering the available power, even when you load all the armarments on board.  It keeps the airplane relatively light on the wing which results in easier takeoffs and landings.

Livery.

I’m sure there are some who were hoping for somethin different but the Kansas Tornado is a reasonably easy to see and, at least to my eye, attractive scheme.

Prop.

It seems to be almost imposssible to fit a large enough 4 blade prop on a model P47 to look really scale but at least we got a 4 blade with a somewhat appropriate shape!

Bad:

Retracts.

I do not understand why E-Flite wouldn’t have put a few dollars into the retracts to give them working Oleo struts.  As light as the bird is, they would not have had to take much abuse but it sure would be nice to have something to take a little of the shock in the case of a poor landing.

Tires.

Combine the lack of functional struts with these rock hard tires and you have zero shock absorption in the landing gear.  Are decent foam tires with “any” give whatsoever so hard to source?  Add to that the pressed in diamond pattern on the tread which looks just silly…  OK, maybe I’m being overly dramatic, but it seems so easy to have done it right!

Prop.

While I like the general idea of a 4 blade and I get that properly sizing one for scale looks is difficult, I don’t trust any airplane where they claim you can run 3 or 4 cells without a prop change.  I mess with prop changes frequently on my aircraft to get the performance I want so I’m very aware that adding 33% more input voltage to the same prop means you have made huge sacrifices somewhere.  Likely its just a compromise that is mediocre for either.  It would have been nice to get 2 props with the aircraft… each actually matched to a 3S or 4S setup.  My observation so far is the prop is probably overloading the 4S setup a touch and pulling more current than it needs to and likely underloading the 3S setup and therefore not getting as much power out of the system as would be possible with a correctly sized unit.

Fuel Tank.

I like the removable rockets and bombs, but why is the centerline fuel tank fixed?  I took care of that issue, but my solution is a bit more permanent… involving some side cuts.  The plane flys even better without any of the extra drag and that is how I fly it most often.

Overall I am enjoying the P-47 very much and I am already keeping an eye out for some replacement struts and/or tires… even if I have to turn to my 3D printer to solve the latter.  She flys very nicely and with the AS3X in the background, is especially stable even with some adverse meteorological conditions.

I have been flying more and more on my 4S 2800 LiHV packs and with proper throttle management, nice 6 minute flights are the norm.  I’m just getting comfortable enough to be working on nice scale takeoff and landings as well as experimenting with making the manuevers more scale like as well.  She can certainly fly like a sport plane if desired so making scale manuevers is something you have to be intentional about.

As I get more flights on it and make any modifications, I’ll be back to report but overall I expect this bird will remain in my fleet for some time to come.

Fully 3D Printed Airplane – Part 4: Flying, Crashing and Rebirth

Well after a short 4 flights, the original 3D printed Wolf is no more….

RIP

For reasons unexplained (I have theories but no real proof of what caused it) the plane crashed and is no more.  Luckily most all of the non-printed parts are fine and ready to grace Wolf 2.

So flights 3 and 4 were both very nice until the fatal dive that ended flight 4.  The wolf has plenty of power with my current setup using my 3S 1300 batteries, was balanced nicely with proper battery placement, and tracked super.  Gliding was very limited, but I figured out that I didn’t have the speed controller set to brake, thus the folding prop didn’t and caused a lot of drag when the motor was shut down.  So problem fixed for Wolf 2!  Flaperons worked but more testing will be done on those and a rudder needs to be fitted.

After experimentation a bit with materials and printer settings I settled on constructing Wolf 2 with the following materials and modifications.

For the body I’m using Poly Light LW pre-foamed PLA in orange.  It is ~35% lighter than standard PLA but still heavier than the eSun foaming LW that my first Wolf was printed from.  It is easy to print as it uses settings akin to standard PLA but a bit stronger than the LW if both are done correctly.  I’m also using this for the control surface just because I want that same color there to give some contrast to the white that I’ll use for the wings proper.

For the wings, horizontal stabilizer and vertical fin I’m using Colorfab LW PLA.  This is very similar to the eSun I used for the first Wolf but it is much brighter white, which I prefer if I am not going to paint, which is the plan.

All parts that need to have more strength, I’ve used eSun PLA+ in either white or orange, which isn’t a terrible color match to the Poly Light.

Next I needed to do some CAD work to create a workable rudder.  Here are my diagrams to create the rudder versus the standard fixed vertical fin.  I cut apart the existing fin and added some bevels to create each new piece then added a simple control arm on the moveable part.

Fixed Fin

Moveable Rudder

My biggest issue with this was that the structure at the hinge point was, perhaps, going to end up being a little weak.  I think I need to improve these with some hinge pockets and reinforcing in that area but for Wolf 2 all I did was manipulate the vertical fin in the slicer program to do a fairly dense infill on the leading edge of the fixed fin.

I didn’t even do that on the rudder proper, instead opting for some Gorilla Glue that expands a bit as it dries to help the hinges grab to the inside of the rudder.  If I ever build another I’ll probably go steal the aileron hinge pocket design and put a couple of those in the rudder and fin rather than mess with filling that area.  Maybe with a small bit of bracing.

I also had to add a second servo holder in the body… easily done by just printing another servo mount and gluing to the wall under the cockpit area… and add a control rod tube extending back inside the body to the right point.  That took some measuring/CAD manipulation and just good old fashion TLAR (pronounced Teelar… That Looks About Right) to get the rod guide tube in place without causing any binding.

Printed parts soon began to fill the table

And before long I had this

Pretty much ready to fly…

And here’s my rudder… working well.

The next thing I decided is that if the prop folded it could conceivably catch on the square hatch latch that protrudes upward from the hatch cover.  If it did, the motor would not be able to start up again and could cause some issues.  Even if it didn’t catch a direct shot to the side of the latch could cause some problems so I designed this hatch latch cover and prop deflector.

Here it is glued to the latch.

If you do something like this make sure you only glue it to the latch and not the hatch or your hatch may no longer be removable!

After all this the aircraft seems to only weigh about 2 ounces heavier than Wolf 1 and I can now report that after 2 additional flights, Wolf flys really well.  With the folding prop working correctly and the use of rudder to make slow flat turns, glide capacity seems to be increased and with a few more flights and possibly trying some smaller batteries I’m hoping to catch enough of a thermal along the way to do more than just “slow the fall”!

I’ve thought about making a removable wing version of this but I don’t want to add the weight I think that would require with all the reinforcement and mounting hardware etc…  For now, as long as she behaves and I don’t do anything stupid I expect this one will transition from 3D printer experiment to just another member of the flying model fleet.  What more could you really want after all?

I’ve got a couple ideas for the next model I will print and a couple other ideas for smaller 3D printed RC aircraft related projects to get started on as well so hopefully more on this type of thing will show up here soon.

New Freewing JAS-39 Gripen… Good, but not my cup of tea.

I recently aquired a Freewing JAS-39 Gripen. 

Up until recently, I have never been particularly interested in flying EDF aircraft but with the latest updates in battery technology allowing for more and more energy per ounce of battery and the shift toward more and more of these type of aircraft being available in ARF or RTF foam bodied airplanes I have begun to consider having one or two in the fleet.  I did some research into available A10s and didn’t find one that really met my personal requirements.  Same for a couple other models.  In the end it came down to an impulse buy from another club member at a nearby swap meet.  He had an airplane that had always interested me and it was essentially new and at a good price.  Not least of all, there is going to be an EDF only event at the field this summer so I wanted to have something nice for the event!

As with most warbirds that I purchase, I did some research on both the real airplane and the model.  First, about the real airplane.

The Gripen is a swedish multi-role fighter that is largely considered to be one of the top two most capable fighters in the world (the late model F-16 is the other and they stack up very well against each other) if you exclude stealth aircraft.  By most accounts it is one of the best gen 4 jets ever built and it continues to be upgraded.  Its distinctive canard design and power to weight ratio make it a very capable dog fighter and the advanced electronics packages and flexibility of weapons payloads make it an extremely dangerous opponent in BVM (Beyond Visual Range) combat.  The F16 is also a very nimble and highly powered platform with similar capabilities… it just gets there by having more thrust to offset its heavier and larger chassis.

As far as the model goes, research says this airplane has a lot of capability depending on how you set it up and fly it.  There seem to be three common complaints from those who own the airplane.

  1.  It is rather large as compared to other aircraft running a similar power system which leads to complaints that this results in it being a bit heavy for this system and therefore not as high a thrust to weight ratio as some would like.
  2. Using the recommended battery size and capacity results in an aircraft that is nose heavy compared to the recommended, which results in an inability to perform certain manuevers.  A select few who seem to be well respected say even the recommended balance point leaves the plane significantly nose heavy.
  3. Using the recommended battery also results in short flight times… perhaps even compared to most EDFs which are somewhat notorious for short flight times to start with.

I’m not as concerned about the first issue as I haven’t done much EDF flying and am not all that fond of high speed so while I wouldn’t mind to have some extra punch available to me, I’m not looking for a lot more speed than is necessary to make the airplane fly well… and it seems to be capable enough by that measure.

Items 2 and 3 are somewhat of a concern and are of course intertwined.  In most electric aircraft, you have the option to add a bit of battery capacity if want to extend flight time, but with this airplane, adding a larger capacity and therefore heavier battery will just exacerbate the nose heavy condition as the battery is in front of the balance point and can not practically be moved rearward to compensate.  I don’t like extremely short flight times and I would like to explore some high alpha flight which requires a proper balance point to perform.  In addition, since the airplane is already a bit on the heavy end of things, I don’t really want to add dead weight to the tail to force the balance rearward.  There was no apparent solution…  Welcome to the world of EDFs and aircraft design I guess… Everything is a compromise.

Further research along with some fortuitous timing led me to what I hoped would be some improvements.  I won’t go into a lot of long winded discussion… maybe another post… but the answer seemed to be to use a battery that housed a bit more energy with minimal weight penalty.  The best thing available looked to be the SMC LiHv packs so I ordered a couple 6S 5300s.  They are no heavier than many other 4500-5000mah packs and pack a bit more punch than standard LiPos due to the HV cells.  Best I can tell, they are the bomb!

I flew the Gripen for just 2 flights.  It took off beautifully from our Geotex runway and tracked nicely in the air as long as you kept a good amount of power on it.  You could slow down pretty well and the plane would continue to fly but it starts doing a bit of rocking which indicates you are approaching stall.  That is a good thing compared to many jets who (as I understand it) just drop a wingtip and stall with less warning.  Credit to the aerodynamics of that big delta wing I suppose.  Visibility leaves a lot to be desired between the gray and the arrowhead body shape, there isn’t much to keep me oriented aside from keeping it close.  I added some extra markings between flights 1 and 2 which helped but to get much better I’d really have to do some thing drastic.

And then I had to land it.  I probably carried more speed than I had to but again the big delta wing makes itself known during the flare as you can really get into a fairly nose high attitude as you land which results in smooth landings with little load on the gear.  Both flights the landings were really pretty.

I didn’t really get a chance to do much trimming or playing with rates and mixes as the flights were by necessity short as the power system is typical from what I understand… which is to say inefficient and power hungry!  The good news is it apparently needed little to no trim so I didn’t need much trim time!  By the time I got a bit comfortable with it I was on approach.

I flew the first time for 3.5 minutes before landing with a decent battery margin and the second time with a bit more crosswind and holding a bit more speed during the flight for only 3 minutes.  The first time I had a decent margin of capacity left but not a ton and the second it was a bit lower than where I normally like to land.  This is just far to short for me.  I couldn’t get the plane up and comfortable with enough time to actually explore much of the flight envelope and I also didn’t like how fast it has to fly in order to fly well.  That also left me no time to try out different mixes, play with high alpha manuevers etc…

Maybe I could adjust to it eventually… but I don’t think I’d ever be really happy with flying it.  Having a fast flight regime is great, but I also want to be able to fly slow and gentle.  I have planes that can do both but I don’t this is ever going to get there.  I’m also concerned that if I try to push it to do what I want it to do I’ll find the hard edge of control one to many times and crash the plane.  There are just to many other planes I would rather fly and/or want to own to hold on to this one.  This one flys to much like its scale counterpart… fast, powerful and heavy.  I don’t think EDF fighters are for me.  For those who like these type of airplanes, I suspect there will be some folks who will love it.  Just not me.

Maybe an A10 or L39 someday…  In the meantime, anyone interested in a low mileage fighter?