Category: Building

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First ever ducted fan electric for me… Alfa F-16C

The RC community is a great resource with worldwide reach and it is fantastic what you can learn and the support you can get just for the asking.  It has always been my hope that something I write here will help out someone else… beyond just entertaining.  Sort of my way of passing it on.  In this case though I got some excellent help from a member of the community who I found on another web site.

Thanks to a posting on the RCGroups web site and a quick response from a gentleman over in England, I now know that what I have here is an Alfa Models F-16C.  Alfa Models appears to be based over in the Czech Republic and available only directly from them at this point.

Someone wanted this one bad enough to order and pay some substantial shipping or perhaps a US vendor carried them for some time??  In any case I now have access to the instructions so I have information on the power systems that are recommended, though I can’t tell whether this one has one of the “stock” options or something else, plus some idea of what size battery to run, where it should be balanced etc…

As I move forward on the build and fly, I will post more here.

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First ever ducted fan electric for me… whatever it is!

An F-16 finds it way to my hangar

Went to a swap meet on Sunday and along with a few little odds and ends I ended up with this:

I’ve searched on line and can find no mention or image of this little foamy.  I’ve been wanting to try my hand with something a bit faster… If for no other reason than I’ve never flown anything with much speed and my assumption is this will likely fit the bill.  Also, I’ve never flown a ducted fan either so maybe get a couple of firsts in one!

At first glance I thought this would be a pretty plug and play, throw it in the air and go option… but after getting the plane home I’ve found a bit more of a project.

First, I was trying to get the speed controller out where I could get a good look.  Since I can’t find any info on the airplane or it’s power train, I have no way to know what battery it should use, what current it will pull, etc…  I was hoping the speed controller would give me some idea what kind of “not to exceed” numbers to look at.  Here is where the speed controller is buried.

Yep, that’s it way up there in an almost invisible location… sigh.  After pulling one nylon screw to pull out the “scoop” I was able to remove the controller, motor and inadvertently the thrust tube that guides the air stream smoothly  out the tail.   Here’s the speed controller with nary a part number, label or any other identifying mark in sight!

That being no help I looked over the motor and ducted fan unit hoping for some help but as you can see it was not much more illuminating.

I eventually took out the guide tube as well…

…and cleaned up all the parts, scraping off excess glue in some areas, re-gluing others etc…  In the process I found some suspect wiring that I intend to replace and clean up, extending some wiring a bit so that the speed controller is bit more accessible!

Here’s the wiring that needs some work.

Here you can see the access points I had to open up to get the thrust tube back in place.  You can also see the one issue I had known about… the aileron control horns seem to be missing!

 

After all that I decided to do a test run just based on size and best guesses so I tossed a 3S on the speed controller, pulled the power pin from the ESC to the servo tester and laid it out on the table top…

The initial run was promising with ear splitting, vacuum cleaner on crack sounding rpms.   That IS what an electric ducted fan is supposed to sound like, right?

After I rework that wiring a bit, next on the hit parade is to put my meter in line and measure current draw at full throttle as another data point toward picking the right battery.  Then I can get back to reassembly and installing some replacement control surface horns.

Then maybe estimating some sort of balance point/CG and installing a receiver and radio setup… This thing is practically bind and fly, right?

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Tugster Tug Boat kit by ZippKits.com

During our sojourn to Toledo, Ohio for the annual weak signals show many of us picked up some new toys.  One of the items that found its way home with us was the ZippKits “Tugster” tug boat kit, purchased by my friend Steve.  He had the idea of building up the Tugster for use in aircraft retrieval.

Now, about 6 months later, the little tug boat has been assembled and prettied up for its big debut.  I think Steve put it all together in just the last couple weeks.  Here is the big launch.

From Steve’s description, the little tug went together quickly and fairly easily. And it appears to have good power!

Steve also reported that the Hardware Kit was quite complete and had pretty much everything needed minus the radio system (receiver and transmitter needed).

Here is a side by side with my Timber out on her floats for the first time.

The little boat seems to have quite a bit of power.  Certainly it easily shoved the Timber around!  The supplied batteries (2 x 6V 4.5AH batteries) needed only 450mah to recharge to full after out poking around at the pond for the better part of an hour the other night so it is hard to imagine recharge being needed during a day at the lake.

The Tugster may see some action here in a couple days as we have our club float fly this weekend.  We’ll see how she does as a real work boat.

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Extreme Flight 74″ Laser – Build nearly complete

The Extrem Flight Laser has been in the shop now for about a month and I’m finally getting close to flying status!  My final items to complete are to get the speed controller and receiver installed, do the radio setup and then go back through and do final checks on bolt tightening, gluing any joints that need it and seal all the hinge gaps.

Overall, the instructions and included hardware seem to be good quality and short of flying it, I am pretty happy with it so far.  I’m going to get a bit nit picky over the next couple of paragraphs in hopes that this will help anyone else who is working on putting together.  There are a few shortcomings in the instructions worth noting and a couple tips I can pass on as far as what to do (or not) that may prove useful.   So here is my summary of the good, the bad and the ugly of building this ARF.

First off, when installing the control horns you need to remove some covering in order to get a good glue bond.  The instructions for this are pretty good but I would recommend a couple of ways to make this easier.  First, when drawing around the control horn base in order to know where to cut, I suggest a white board marker.  They are easier to wipe off with just some alcohol or window cleaner.  Also when removing the covering I remove only to just inside the line so that the base plate actually slightly covers the edge of the material.  This helps ensure that the material will never peal up around the horn and the result looks very professional.  Secondly, not only here but pretty much anywhere you need to remove covering… I highly recommend use of a soldering iron.  With minimal practice you can move at a rate that doesn’t char the wood underneath but just melts the covering.  It also seals down the edge as you go.  I find this method far superior to use of a razor blade or Xacto knife.  Extreme Flight’s manual mentions this option in one place but then often says to use a blade in many others.  I’d stick with the Soldering iron in pretty much all cases.

While on the subject of control horns, for some reason I got two sets of of rudder horns with no explanation as to why or what I might want them for… still don’t know.  In any case, I would install these dry and mark them once you measure for proper centering.  The “barb” on one side that I thought would end up against one side of the rudder to aid in alignment… does not seem to be any such thing and I don’t know why it is even there…  Just be cautious that you get the centering correct here.

One preference/ nitpick of mine is the tail gear mounting method.  I’m used to having blind nuts embedded but this gear mounts only with wood screws.  I would love to have the blind nuts as I think they result in a stronger mount.  Hopefully this mounting method will be strong enough.

The next note I made while building was regarding the rudder pull-pull mechanism.  First, if you have never put one of these together before you should go find a step by step instruction set that will walk you through everything you need to know ’cause what is in the manual for the Laser is not that!  If you’ve done a couple you probably will have no issue with this one.  One odd note is that they specify to crimp the aluminum tube with side cutters???  If your side cutters are worth a darn and you squeeze firmly you will end up cutting that tube and probably the cables themselves clean through.  A standard pair of pliers works quite well, thank you.  Don’t use side cutters!

Next, I noted that the instructions for installing the wheel pants had a couple of shortcomings.  First, when they have you drill a hole, they do not tell you what size hole… you can figure it out of course but it would be nice if they just told you… sorry I didn’t write it down or I would have provided that here (silly me).  Also when they have you install the blind nuts it required an excessive amount of force to get the little sharp prongs to push into the wood because the back of the wood inside the wheel pant has a fairly heavy coating of fiberglass/resin which necessitated a pair of channel locks to get the prongs to penetrate!  I felt like I was risking a good amount of damage when I did this but that is what it took to get them to embed flat…  and you need it to lay flat to keep it from rubbing against the rim/tire.

One error I ran into as I mounted the motor is the stated distance from the front face of the motor box to drive washer should be 6-3/8″… My ruler says it is actually 5-3/8″!  If you extend it to 6-3/8″ the cowl will not go back far enough to mount.  Luckily, I checked before I got things mounted.

OK, that’s about it.  Everything else seemed straight forward to me and I appreciated the packaging of the parts (individual bags with labels for each set of pieces).

I’m looking forward to getting started flying soon and the real test will be flying characteristics and how well she holds up over time.  Looking forward to messing with setups, props, batteries and telemetry to see what works best.

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My Shop… Truth Revealed!

So by way of a confession of sorts…

I consider myself a moderately skilled assembler and occasional builder of RC airplanes.  I know a couple guys who are true craftsmen.  Guys who build scale aircraft that the Smithsonian would be proud to display… I’m NOT that guy.  However, I strive to build a safe to fly, low maintenance flying machine and for the most part the results seem to have few “avoidable” issues.  I enjoy working on my aircraft in the shop (usually) and when we moved a few months back, one of the primary considerations was shop space available OR a lower price space to build an appropriate shop if none was part of the package.  This eliminated a bunch of homes that just didn’t have anything appropriate.  The final purchase was a bit of a compromise (what isn’t) but I am now working in approximately 350sq feet of 2nd floor/converted attic space inside the house.

I had to forego most of the power tools and carrying larger craft up and down the stairs can be a challenge but not having to go outside to reach the shop is pleasant and walking the stairs is good exercise, right!  In the center of this space is my 12′ conference table re-purposed for RC work.

At this point, most folks proudly post their picture of the shop with beautifully laid out peg boards, immaculate clean tools, perfect lighting and a completely clean benchtop…  well, honestly mine usually looks like this:

You can see the tail of the 50cc powered P-51 (it needs some engine mount tightening and is a recent donor of a receiver to the Extreme Flight 74″ Laser project which is currently underway).  Most of the rest is part of the Laser project or some random stuff I needed or used in the last week or two on other projects that have come and gone.

See, I am of the opinion that a clean workbench is one in need of a project… or five and any open space is good place to start another one!

Realistically I came up to the shop the other night and saw this and snapped the pic… It really is pretty representative of day to day life in my shop.  I immediately started to picking up and putting away some of the tools etc…  My usual breaking point is typically when I come to the shop and realize that I have some of my more recent projects literally piled on top of earlier projects.  At that point I know I need to clean up a bit and will put away a majority of the tools, do a little cleaning where needed and get at least some open tabletop space cleared so I can start a new project!  I don’t really try to have all the space cleaned up at any one time.  It’s more of a rotation system.

 I rarely work on only one project from start to finish without interrupting that project to work on several others.  When one gets close to completion I usually get enthused and buckle down and finish it up depending on my enthusiasm level for it by that point.  Besides, several of my flying buddies are frequent visitors to the shop, typically with their latest RC airplane that needs some TLC and those “quick fixes” will of necessity preempt whatever longer term project I have going.

So there you have it.  This is my reality.  Ain’t it great!?

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Freewing 80mm Super Scorpion EDF Jet

Recently, My flying buddy Martin has decided to branch out into some ducted fan electric craft and one of his first is the Freewing  80m Super Scorpion from Motion RC.  Martin had the new aircraft shipped to my shop and today he came by and we did most of the assembly.  

The first observation I would make is that we spent about 4 hours today doing assembly and we got to the point where all we need to do is plug in the receiver and set the throws and it will be ready to roll.  Maybe we could have cut it back a bit but don’t believe the place on the website that says assembly time is 30 minutes!  Just scroll on down where it says 3 hours and you are in the ballpark.  The other specs listed on the site seem to be accurate, even down to the ready to fly weight.  Measured with a 4500 6S on board, we measured Martin’s aircraft as just a couple of ounces over 5 lbs just as the web site reports.

Similar to the manual for the P-38s that I recently got from Motion RC, there is a lot of “stuff” in this document that describes assembly that is already done out of the box.  This is distracting and it sometimes makes it hard to figure out what the next “required” step is in the assembly process.  Unlike the P-38 this model however does not have a full assembly video on the web site and luckily it isn’t needed as there just aren’t that many pieces and assembly is not all that complicated.  Just walk through the manual and keep skipping forward when you read the parts that are unneeded and you’ll have little trouble.

There are only a couple of places where I can give you some advice that might not be obvious. 

  • When you put the screws in to attach the wings to the body, be careful to route the wires appropriately then be very careful that the screws are actually going into the holes in the plastic.  The best way to avoid this is to just start each before you fully tighten any.  A simple thing, but easily overlooked.
  • When you attach the vertical fin, insert the front screw first but only a couple turns.  Then do the side screw and tighten both down before installing the screw from the top.  Otherwise it is very difficult to get the top screw to hit the pre-drilled hole in the wood plate that it attaches to.

And a critique or two for the manufacturer and distributor.

  • Somehow there were only 2 of the 2:1 servo connectors and 1 3:1 servo connector included in the kit, even though the manual clearly indicates there should be 3 of the 2:1 connectors.
  • On the website it is implied that you can remove the wings and elevators and the vertical stabs (presumably) in order to carry it to/from the flying field.  “Removable wings and vertical stabilizers for convenient transport”.  Perhaps this could be done a few times in order to ship the aircraft from place to place, but these self tapping screws and plastic and wood into which they are screwed are not what I would expect if this were actually the case.  I would expect most folks are only going to take these screws back out if a repair is needed.  Anyone who needs to take this aircraft apart in order to get it to and from their flying field should look for a better alternative.

Since the high today in our area was 38 degrees (about 20 degrees below my minimum standard for comfortable flying) we don’t yet know how it flies but here are some pictures of how it looks.  Some highlights I would point out are the nice shock absorbing struts, the cockpit detail and the attractive and hopefully easy to see color scheme.  Though the aircraft is not quite as large as Martin had assumed, I think he is still fairly happy with the overall look and build quality of the aircraft.

Here is the nose gear showing the nice shock absorbing strut

 

Here’s a shot of the actual functioning inlet that feeds air to the ducted fan

  

And the finished product.

Looking forward to see how it flies.

 

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Motion RC P-38 – outboard flap issue resolved

So, the silver P-38 sitting on my bench has one flap servo that appears to have the servo arm incorrectly installed.  See my previous post on this topic for details.  Motion RC P-38 – outboard flap issue

I was gathering the necessary tools to slice into the plane as described but decided to do a bit more research and found that others had pulled other servos out of the P-38 and reported that they were glued to the paint, not directly to the foam.  This gave me a bit more confidence that it would come out without tearing up the foam.

My first thought was that I would have glued the servo in directly to the foam…  which would have made this worse… so good thing no one asked me!  So with this new information I went back to the shop and made a careful incision all around the edges of the servo where any glue might be holding it and then with a pair of pliers I just grabbed on and started yanking and wiggling…

As advertised… the paint stuck to the glue and thus to the servo but the foam is largely undamaged.  With this I was easily able to then remove and replace the arm into the correct position and things then lined up nicely!!  Another hurdled cleared.  Glad I didn’t get in a rush about cutting into that wing!

We are now much closer to flight on these two birds and I’m starting to get back closer to the initial excitement to fly them that I had when we placed the order.  Just another session or two at the bench to get all the throws and rates set up and we should finally be in a flight worthy status… just in time to wait on the weather…

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Motion RC Pacific Green P-38 progress – near flight worthy

After an email exchange with Motion about the sheared screw in the back plate of one of the spinners, they shipped me replacement spinners and screws.  While I still dislike this setup, I’m going to give it a try for at least a few flights.  To replace these with something more appropriate in a two blade, as discussed in an earlier post, is just more than I want to spend at this point on this airplane.

Moving forward with replacing the screw led to applying the wire covers on the bottom of the plane.  I deviated a bit here and just used some clear packing tape to hold these in place.  I’m not entirely sure how well that will hold up but we shall see.  I hesitate to glue those in case I need to get back in there and rerun any wires or the like.  This was followed by adding the antenna on the nose as well as the counterbalances on the elevator and the “decals”.

The decals seem to be a mixed bag on this bird.  First, the good news.  Many of the decals seem to be vinyl or something very similar and they seem to adhere well and look fairly good.  If you haven’t dealt with vinyl before, these are not peal and stick decals.  You do not float them off the backing like the plastic models of old.  Nor are they applied by just peeling them off the backing and rubbing them on.  You do that, but then you peel the top, clear plastic looking material back off the plane and leave the vinyl behind.  This can be a bit tricky at first.  My tip is to use something like a pencil eraser of the round screwdriver handle end to rub with a bit of force in order to get the vinyl adhered to the airplane and then be careful how you peal the carrier off.  Watch for the vinyl to lift back off.  If it starts to do that you need to rub some more!

The vinyl parts are the majority but there are some of each of the others as well.  This is very odd.  The decals for the props seem to be the old water float decals and in my opinion they are the worst of the group.  The props are not perfectly smooth with a fine grained surface and this makes it that much harder to get a good adherence with these water slide type decals.  These are the worst of the group and I really don’t understand this choice as these are the most likely to fall off I would think.

Finally the stars and bars seem to be just a peel and stick type.  I would much have preferred vinyl for these as well but they look decent.  I just question their longevity.

There is a full page diagram included that shows where to put all the small vinyl decals and the opposite side shows the relevant parts of the aircraft from various angles in order to allow for positioning of the nose art, kill marks etc…  It has been noted that there are some minor errors with the placement of the small decals for things like hatch cover markings, no step and similar items.  I don’t plan on applying all of them as most are invisible at more than 3 paces anyway.  If we get a lot of snow and I’m stuck at home for a full day in the next month or so I may go back and apply a few more but in my opinion they don’t add much.  I did the nose art and fuel cap markings, kill marks and few other larger markings and stopped at that.  The rest seem to be diminishing returns in my book.

I also had the displeasure of applying the slide on decals to the props.  I hate that these hardly seem to stick at all and appear to be the lowest quality of the markings as they are also some of the most visible when the plane is sitting idle and add a nice look to the props.  Unfortunately one of mine has already fallen off and I’ll be surprised if they last past flight 3.  Oh well, as we say at the field: “50 feet and 50 miles an hour”  If you can’t see it in that condition it isn’t worth worrying about!

After a batch of other sundry tiding up, labeling the wires etc… I’m pretty close to flight worthy.  Here’s what she looks like sitting in the new “up stairs” shop.

She’s looking pretty good.  Still not sure what to do about adding some invasion stripes on the wing and booms… I think it will need it for better visibility but I hope to get a few flights in before I get involved in that.  I’ve never been much of a painter so not looking forward to applying those but it may become a necessity.  Unfortunately there are no decals or vinyl for those included with the plane.

I think about all that is necessary before the first flight is possible is to set and double check the throws on the primary flight surfaces and check the speed controllers are calibrated/coordinated.  Beyond that there might be a few tweaks toward getting the telemetry set up the way I would prefer and checking balance with various battery options and it will be as ready as I know how to make it.  With a pair of 3300mah batteries on board it weighs in at 8lb 6ozs…  I’m expecting very war bird like performance but hoping (maybe wishing) for a bit lighter feel than my 24lb Mustang!  ðŸ™‚

I’m taking a break from this one for a bit and working on getting the Pacific Silver version ready for Kelly.  We are having some issues getting his Graupner radio to do what we need and I keep missing out on making contact with Graupner support to iron it out so it has (pardon the unintended pun) stalled out for the moment.

 

 

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Motion RC Flightline P-38 – Hinge fix

After some communication with the tech support folks at Flightline, I embarked on a plan to repair the poorly glued aileron hinges.  To better explain the issue, here is a short video showing the undesirable motion of the aileron on Kelly’s silver P-38:

The Motion RC folks explained that the hinge in these planes is basically a rod that runs through the aileron with tabs that pivot around that rod extending into and glued (ideally) into the wing.  It’s these tabs that are apparently not secured very well in the two P-38s we received.  They suggested that I carefully drip some glue down into the pockets in the wing.  The following is how I carried that suggestion out:

This was unfortunately not unique.  At least half of the aileron hinges across both aircraft were found to be loose to varying degrees.  This is disappointingly poor quality assembly by Flightline.  Of course, the fix was not terribly onerous but I wonder how many folks have assembled the airplane and only found out this was an issue when the airplane shed an aileron or worse??

In any case, if you build or have built and are flying one of these I highly recommend you check your aileron hinges before you fly.  This could easily cause a loss of control with serious ramifications.

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Motion RC / Flightline P-38 assembly… more issues crop up!

As my buddy Kelly and I worked yesterday on the latter stages of assembly, we came upon yet another issue with these birds.  As he was assembling the linkages and connecting them up, he noticed that there was some slop in the movement of the ailerons.  Here is what we found:

Above is the Aileron with the aileron centered and the servo holding the center position.  I am applying very light pressure to maintain this position.

Here I am applying a small amount of opposite pressure.  Again the servo is holding center position and the linkage has almost zero slop.  All of this motion comes from the hinges sliding around in the pockets (I think inside the aileron versus the wing…)

In this case, both of the hinge points (I think that is what they are) on the inboard end of this wing panel seem to be completely unattached on the aileron end.  I am rapidly becoming very disappointed with the quality issues on this airplane.  This is my first FlightLine and Motion RC purchase and I’m not exactly encouraged to spend more money with them at this point.  Still, I have had some issues with other manufacturers aircraft “out of the box”… and some of those have become my favorite planes.  Often this is based on a combination of flight performance and support from the manufacturer so I will withhold any final judgement until I get some response from Motion RC and I have a few flights on the bird under my belt.

Hoping for better things…

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