Flying weight about 15 lbs
My PZL_104 Wilga aircraft ARF from Black Horse Models. This aircraft is a STOL civilian plane from Poland. I really liked the uniqueness of this model. I wanted to maintain the appearance of the cowl, so I used a motor designed for sailplanes. It’s specs are 40-30-390k 8S 2200W. The electronics are Spektrum SMART receiver, ESC, batteries and a DX9 transmitter. The pilots are removable and are secured by magnets. Here is a link for more information on the Wilga. https://en.wikipedia.org/wiki/PZL-104_Wilga
Weight 14 lbs
By Wayne Walker, SEFSD
It all started when I was given an old Multiplex AcroMaster pattern plane. I won it because I bought the late John Forester’s two model sailboats. They say never look a gift horse in the mouth, yeah right.
After I got the sailboats sorted out and ready to go sailing, I turned my attention to the AcroMaster as I wanted a rough & ready plane to practice my maneuvers & landings.
I went through it and everything seemed all right, so I found a 3S – 3000 battery for it, and put it in place, it didn’t balance at all, nose too heavy. Then I noticed it had a pretty big motor for that size plane, all the better I thought but it was obviously too heavy & why the plane didn’t balance with the battery in the location designed for it. Moved things around & added 4 ounces of lead to the battery and it now balanced.
Took it out to the field to test fly it. Roll out was good, but as soon as it was airborne it didn’t seem to have good control. I was able to make a 180 from the takeoff, but then it was all over the place! It ended up crashing over by the RotorPlex area. When I was gathering up the pieces, I noticed the right aileron was pulled out of the wing, hmmm probably what caused it to go out of control.
Later back at my shop I glued everything back together with my trusty 30 minute epoxy and paid extra attention to getting the aileron flex hinges glued in with plenty of epoxy to make sure they held in the future. I also had fun gluing the nose pieces back together and wrapping a fiberglass bandage around it all to keep it in place and hopefully straight and sound.
Back to the field to try again. Takeoff was normal & turnaround normal then as I got it about even with me where I was standing all heck broke loose and it was uncontrollable again! And it crashed.
When I was gluing things back together again, I noticed that most of the glue joints had turned brown, I just figured the builder used low grade epoxy or rubber cement. I was also mystified as to why the recently epoxied aileron joins had pulled out again. I asked around and everyone I asked said they thought the epoxy was the best way to glue Multiplex’s Elapor foam together.
Well, it turns out that epoxy & carpenters glue only proved a half-baked bond to Elapor & similar shiny skinned plastics! After getting what I term “Old Wives” tales of which glue to use I found the following on several Multiplex model airplane construction manuals:
From: MULTIPLEX Modellsport GmbH & Co. KG
“This model is not made of Styrofoam™, and it is not possible to glue the material using white glue, polyurethane glues or epoxy; these adhesives only produce a superficial bond which gives way when stressed. Use medium-viscosity cyano-acrylate glue for all joints, preferably our Zacki-ELAPOR®, # 59 2727 – the cyano glue optimized specifically for ELAPOR® particle foam. If you use Zacki-ELAPOR® you will find that you do not need cyano ‘kicker’ or activator for most joints.
However, if you wish to use a different adhesive, and are therefore obliged to use kicker / activator spray, we recommend that you apply the material in the open air as it can be injurious to health. Please be careful when working with any cyano-acrylate adhesive: these glues can harden in seconds, so do not allow them to contact your fingers or other body parts. Wear goggles to protect your eyes!”
In another Adhesives note I found the following advice on technique.
“On one surface spray on Kicker and let dry for several minutes.
On the other surface apply Medium CA as needed.
As the join will set in a very short time align the pieces carefully before letting them touch as there will only be several seconds before the CA hardens making a permanent bond.”
I found that using this procedure results in a 2-3 second flexible time, not really enough to align large pieces of work like an AcroMaster wing panel.
So with all this new information, what did I do? Of course I ran my own tests to see how well these adhesives bond Elapor. I also did a test of Formula 560 Canopy Glue.
Here’s the picture of the test samples I glued together and then 24 hours later tested for strength. All samples were on virgin Elapor foam.
I tested both “Plain”, no preparation, and Prepped with alcohol and then sanding to remove the gloss on the surface of the foam.
The Canopy Glue 560 was the weakest with only a small pressure to part the two pieces.
Using Odorless CA was almost as weak as the Canopy glue.
The high quality Epoxy joined pieces were next in strength, 1-3 pounds of pressure to break the bond.
I didn’t test White, Carpenter’s or Ambroid glues as these are seldom used in modern model construction.
The Medium CA plain & prepped samples I was not able to break apart, but my arthritic hands were only able to apply about 5-10 pounds of force to the joins, this is probably equivalent to a hard crash to the joined pieces.
When gluing Multiplex Elapor and similar shinny skinned foam use Med CA with or without Kicker, it will be the strongest join available, and no prep is needed to make a strong joint.
When gluing Styrofoam pieces use Odorless or Foam Safe CA glue, or epoxy.
As far as Hot Gun Glue goes, I’ve bought several Chinese models that have them, but don’t recommend the technique.
As an aside, I found that Du-Bro & other hardware suppliers have discontinued the line of hard plastic hinges and instead recommend the Fiberglass mat type of hinge material. I’ve now substituted this for all my flex hinges.
By Carl Murphy
One Airplane, Two Batteries, an Hour of Carefree Flying
(0) to (750) Feet At a Count Of Ten (5S) or Thirteen (4S) or Fifteen (3S)
This is an instruction by examples of electric propulsion choices for a four foot wingspan, molded from impact resisting foam, reinforced, light wing loading, semi-scale RC Piper Cub. Chronicled are testing, things gone right and wrong, and, RC flying as a whole experience. From light weight one and an eighth inch diameter outrunners, light to medium (37) mm diameter outrunners through geared competition inrunners, four combinations were selected as optimal. From relaxed to outrageous, flight times start at twenty-five minutes on just the motor and battery. Altitude gain at maximum climb for count of ten ranges from three hundred to seven hundred and fifty feet, glide back down from a seven to one ratio to fifteen to one.
Tuning Is Worth It
Where I started RC flying in Orange County, CA, back in the mid 1990s it was next to the current F5B world champion and six other current or former thermal, slope soaring and pylon RC pilots. At San Diego’s Mission Bay my company includes a former F5B world champion who manufactures the worlds best RC racing motors plus several more national and international ranking F5B, F5D and F3A precision aerobatics RC pilots. As a friend in low places (I gave up my Piper Pacer at the start of the second great depression, for ten years I was almost, but not quite, broke) though the experience with getting a RC airplane set up right was not lost on me. Significance; Nobody has ever seen a Fun Cub fly this well, when I loan my RC airplanes to other pilots they don’t get as much performance or duration. Part of that is having flown enough to be “one” with this airframe.
This article is paired with articles about The Mentor Propulsion, a larger and heavier airframe and an article about The Cost of Flight, Outrunners verses Inrunners. Continue reading
By Bob Stinson
64th Aggressor Squadron, Callie Graphics and an Eflite F-16
By Otto Dieffenbach
This is a project I started on after the first of the year. The plane is Lassi Nurila’s version of the Sensation F3a pattern competition bipe. The design originated in Germany around 2012 and has captured many titles in world competition. Last year Lassi flew his version to 5th in the World Championships. I started flying modern pattern with Bruce Brown once a week with a used 2 meter plane. I realized that I enjoyed the flying as much as classic pattern and decided to up my game. Lassi was kind enough to work with me from Finland. He layer up a fuse for me and I picked it up at LAX. I had the wing/stab cores cut by Eureka and Don did a fine job. I began actual building in mid August and maidened on the 12th of October. It flies very much like a 3D indoor foamy. Effortless knife edge and tracks beautifully.
By Steve Belknap
About 20 years ago I put a cradle on my Sig Kadet Sr. to carry gliders aloft and release them. Recently I pulled out the cradle and dusted it off. Frank G. had a freshly made Goldberg Wanderer he had not yet flown. So I rubber banded everything onto the Kadet once more. Everything worked perfectly. So far I have launched his glider 5 times. On the last flight Frank measured the radius of one of the light standards using the leading edge of the glider. All fixed now and ready to fly again.
Some of the members who were around then might remember my initial attempts to use this launch cradle. They might remember when I launched a glider and the rubber bands released on only one glider wing. The other wing stayed attached to the cradle. It got ugly real quick. Finally, the glider separated from the cradle. The rubber bands did not let go but the glider snapped off the upper part of one side of the cradle. Everything landed OK and the cradle was modified to prevent the rubber bands from not releasing.
Click the pic for a short video:
By Bob Kreutzer
Locked down, but not out.
Last issue I showed my “lock down project”. A good friend lent me His Ender 2 3D printer. At ~$200 it is an absolutely great deal on an entry level 3D printer. I can recommend it. I wanted to add a full ordinance load onto my MQ-9 project. So I jumped in with both feet and learned a new skill. Like most things, once you get the hang of it, well it becomes pretty easy. Basically there are 3 steps.
1: Obtain an STL file of what you want to print.
2: Download a slicing program (more on that)
3: Put your sliced STL file into the printer and press the on button.
OK. An STL file is to a 3D printer as a PDF file is to a regular printer. Nothing more.
A slicing program (I used CURA and do recommend it highly) allows you to place the project in the proper place on the 3D printer bed. It also allows you to size it to your needs. You press the SLICE button and everything magically happens. Then tell it to copy onto a SD card.
Take the SD card and insert it into the 3D printer. Scroll through like, 2- 3 menu options and press “PRINT”. That’s pretty much it.
So here is what I did:
I finally finished the 1.9m Avanti XS (120mm EDF on 12S). Everything is ready to go except for me – I haven’t flown in two months. I thought these pilots needed kindergarten-level controls, so Bert has buttons for “Fly” and “Land.” (I don’t know why most cockpits are more complex than this, because that pretty much covers 100% of what an airplane needs to do.) Ernie is a bit more negative in his outlook.
Setting up your T-28 to race by Steve Neu.
The most important thing that many people miss when starting to race RC planes is that going fast is nothing without control! The FMS T-28 is a small plane and setting it up to race IS very different than for your basic sport flying. Getting the CG and control throws dialed in are key to getting the plane to “go fast and turn left” and keep in control. As a racer running at full throttle— the elevator and aileron travels needed are minimal. A properly setup T-28 will actually be easy to fly with only small control deflections.
The control throws suggested in the FMS instructions are intended for a plane flying much slower on a 2S battery. We are flying much faster with 3S. Here are the control deflections I have on my plane:
Ailerons: 6mm up 6mm down
Elevator: 3mm up, 3mm down
Rudder: 6mm left, 6mm right
CG measured from edge of wing at fuselage opening 71-72 mm—see picture below.
I like about 30-40% expo on both aileron and elevator—helps make the plane less sensitive around center making it easier to do fine adjustments to the plane’s track. A little nose heavy helps make the plane positively stable in pitch and the elevator less sensitive but the recommended CG in the FMS instructions is too nose heavy for my taste. Too rearward CG locations will make the plane neutral in pitch stability or even negative which will make it more difficult to find a stable track down the course. The trade offs in moving the GC is stability vs turning ability with the aft CG setup being able to turn more quickly. You need to be careful with the CG and elevator throws in that if you get too aggressive the plane will tend to snap roll in tight turns.
If you find the racing setting a little too mild for take off/landing and general sport flying I suggest setting up a dual rate switch so you can easily swap from control rate one to another.
Some of you did not read my previous article regarding the “AD” for the nose wheel strut—I learned the hard way that on our rough field the stock strut puts the nose wheel too close to the prop which will result in props getting busted when the blade hits the nose wheel rubber. The fix is easy—just turn the nose wheel around (be sure to put a flat on the shaft on the opposite side!).
Our first T-28 race will be in July!
By Steve Neu – email@example.com
After busting several of the rather fragile 3 bladed FMS 7×6 props I decided to come up with a clean solution to mount an APC 7x6E prop without having to resort to stacks of washers, as the motor does not have an adapter that will work with “normal” props. I designed some parts and thanks to the fact that my business has both a Haas CNC lathe and mill it was easy to get some of the adapters made. No mods of the motor or plane are needed—simply remove the old prop and plastic adapter and put the slotted drive plate in it’s place. Install the smallest hole reducer that comes with the APC prop and balance the prop and slip it over the shaft—then install and tighten the spinner nut and you are done—ready to go race again. I made enough so others who need them can get them—I will keep some in the car so if you need one let me know when you see me at the field. I am optimistic that we will be in a position that T-28 racing can get going again in July.
Here are my May projects: the Ryan STA is a 57” Great Planes ARF from Tower. Needed a smallish wheeled plane as we just got a new site at the school near my house available Wednesday evenings. Nice paved play area leading into a large soccer field. The Skyray was inspired by a foamy project in last months model aviation magazine.
Odie sent in the pics below showing some of his 3D printed projects. The blue plane is a GB R3. This is a scratch build using mainly plastic 3D printed parts. Like many models of full size planes there were compromises such as increasing the wing area to reduce the wing loading. The chord was increased to 120% and the area increased to 160%. Other challenges include making the plane light but also stiff and strong. Wall thicknesses are alway in mind and must be kept thin as possible. He says one needs a good printer to maintain the structural integrity of thin components.
He started with an imported drawing of the plane and created the segmented parts in a professional version of Solidworks.
To keep the tail light he uses balsa for the stabilizers. This also helps with balance. He uses a slicing program, along with Solidworks, to help calculate the weight and balance on the computer before printing the parts.
Printing time is proportional to the amount of plastic used (mass). The GB took about 16 hours of printer time. As with most 3D printed planes, the parts are printed in sections and glued or snapped together.
I just put together the FMS T-28 Trojan. I painted to fuselage this morning. This went together way to easy. Still deciding on sticker numbers or make a stencil. My number is #00. See you on the course. – Carl Cox.
I’m using quarantine to work on a Sebart Avanti XS. It has a 120mm fan running on 12S. The fuse is fiberglass, the wings are wood, and it has a wingspan of 1.8m. For comparison, the plane in my hand is the Freewing foam Avanti S (wingspan 1236mm) that many of us have. I chose a carbon-fiber 17-blade fan (optimized more for thrust than for top speed). – Mark Davis
Hi, Fellow COVID Exiles.
Since I can not fly at either the electric field or the Chula Vista club, I have spent time on a new foamy from Motion RC. This is a FlightLine FW-190 44” model, a bit smaller than I like (due to my old eyes). The model is a reboot of an older design which now has added flaps – but not the proper “scale” split flaps : ( I guess the days when I would spend 1500 hours on an over-the-top scale project are probably over anyway.)
This plane runs on a four-cell, which is one of the reasons I got it, since I have several batteries that can be used in it. The battery bay is extremely tight and required some surgery to get everything in. The model is spectacular in detail and fairly good in terms of scale fidelity. I did it in the optional Heinz Bar #13 scheme, adding my own Photoshopped swastika which was missing on the tail (PC reigns). I decided to try some weathering which I have really never done before. My attempt is terrible compared to the incredible models I see on the internet – but I had fun and it isn’t too bad after all. A little black to hit the panel lines, ocher for oil leaks and where the guns dirty the wing, and blotched silver to look like chipped paint on metal… Everything on the model has been coated with some acrylic floor finish, which pulls it together – as well as sealing down the stickers which, on this model, were not good. The colors and detail was great but they really didn’t stick very well at all – especially the small/thin ones.
Today was spent binding the new RX and setting the throws, etc. Hopefully I will be able to handle this fast little plane, once the field is open again.
I hope all is well with all of you,
I have a plane that was featured in the latest April 2020 Model Aviation magazine. – Randy Mann
A co-worker kindly lent me his Ender 3 3d printer. I have taught myself to use it and am now printing missiles and bombs. In particular, Hell Fire missiles and GBU -12 Paveway laser guided smart bombs for my MQ-9 project. So am learning new skills and moving the MQ=9 project forward in these difficult times. I can recommend the Ender 3d printer as a nice and economical beginner’s printer as it is producing a fine product(s). – Bob Kruetzer
Like most everyone I have done some repairs to my airplanes. But here is something a little different. It’s flying related but not an airplane. In a prior life I had a video business where I would record various events and provide DVD’s and/or downloads. For this purpose I purchased a Servocity Pan and Tilt device (picture below). I would mount my video camera on it and using a hand held wired remote I could move the camera both left to right and up and down. – George Sullivan
Taking video of RC aircraft is a pain in the …. I always hoped I could use this device but aiming it was a problem. So the project I have is in 2 phases. The first phase is to convert the controls from the hand held wired controller to a wireless receiver and my Spektrum transmitter. This was surprisingly easier than I expected. I now have a 4 channel receiver mounted on the device and can control the pan and tilt motions using the right stick of my Spektrum transmitter. I will output the video from the camera to either a small monitor or perhaps a pair of goggles. Here is a short video showing the Pan and Tilt mechanism controlled by the Spektrum transmitter. (https://www.youtube.com/watch?v=TpZS2jtaciw )
The second phase is to solve the problem with aiming the camera. My plan is to put a “headtracker” on the output display (monitor or goggles) and input that into my Spektrum transmitter. So at least in theory the camera should point where I’m looking.
The first phase is completed . Phase 2 is waiting on the delivery of the electronics for the headtracker. I hope to get the electronics by 4/15. If all goes well, an update for next months newsletter.
Like the rest of us, I’ve been “hunkered down” in my case at Casa Gagliardi trying to keep my brain from going to sleep with way too much TV ! So let’s build something…..First it was the Wanderer Glider that Mike Morgan so graciously laser cut for me as it was my first glider back in ’75 after going to Torrey Pines and watching the action there. I had just been transferred here after Recruiting Duty with the Marine Corps in Indiana (can you say FLAT?)
I bought this FD 421 Cessna at Weedwackers and I’m just about done with it. – David Pothier
The stock mechanical retracts that came with the Hurricane were underperforming. I replaced them with the main retracts that normally come with the Freewing Avanti Jet. They fit pretty well with only moderate fiddling and fussing with the mounts. One of the great things about these retracts is they are very inexpensive. Only $50 for the set!
If you are looking for retracts for a project, check out MotionRC.com. They sell the retracts for nearly all their models. You can find all sorts of sizes, configurations and styles. – Steve B.
By Steve B.
Last year I bought the Avanti S from MotionRC.com. Although this is an excellent jet, I wanted it to go faster. The modification required replacing the entire fan assembly, the motor and the speed control. It was all pretty simple to do because al the new parts fit right in where the old ones were. No foam cutting, just a slight change to the ESC mount.
The test flights went perfectly. It is significantly faster than the stock setup. The flights are shorter due to the higher currents. Unfortunately, I forgot to get video.
In order to get the correct motor and fan, I took the easy route and went to our very own ‘motor master’, Steve Neu of Neutronics and asked him. If anyone knows how to make airplanes go fast. . . well, you’ve seen him fly, enough said. Steve created a special wind motor just for this application: NeuMotor inrunner 1412/2D/S/5mm with a Kv of 2400. In this application the motor is using 2700 Watts. The stock motor’s Kv was 1900.
The stock fan that comes with the Avanti is plastic and specially made to mount on their outrunner motor that itself mounts from the rear. The motor and fan are cantilevered off the back of the motor. Seems crazy but it works. This fan cannot accept a motor that mounts from the front. Turns out they have fan housing made of metal and it fits a front mounting inrunner (p/n P0806). I used the fan housing but the fan that comes with it cannot mount to a standard motor shaft. So I purchased a Jetfan 80 V3 from eJets in France. It is made to fit the NeuMotor 5mm shaft.
I bought a Castle Phoenix Edge 130Amp ESC to replace the stock 100 Amp ESC. Current at full throttle is 135Amps. The battery is the stock 6S 5000mAh Li-Po.
I’ll take you through a pictorial explanation of the conversion process:
Below you can see how I took off the motor hatch. The screw eyes made it easy to lift it off (after you remove the screws). Otherwise it is a pain.