Builds & Reviews

199 posts

A New Stall Warning System Based on a True Airspeed Sensor Suitable for Electric RC Models.

 

By: Stephen H. Nussbaum, SEFSD Member since 2010.

BACKGROUND:

Have you ever been caught by surprise when your model suddenly takes a dive and ends up in a heap in the middle of the runway? It’s happened to me and more than once. We probably experienced a stall due to the air flow over (and under) the wing being too slow to generate enough lift to keep the airplane flying. In all real, certified airplanes, the FAA mandates that there is a stall warning bell or buzzer that alerts the pilot when the plane is flying too close to the “stall speed”. When this alarm sounds, it’s time to take action by adding power and/or if you have enough altitude, drop the nose in order to regain the necessary air flow over the wing to generate the lift needed to maintain flight. Sometimes when the alarm sounds your wheels are just a few inches above the runway, ok land already.

In a real plane, the pilot can see his true airspeed on the airspeed indicator. He can get a good idea by monitoring this indicator that his aircraft is moving forward at a safe speed. That is, a speed that guarantees sufficient lift. RC pilots we don’t have that critical piece of information.

I set about to change that for my models and I wanted to share the results of my efforts with you guys. I have developed a stall warning system that will provide you with a true airspeed display and issues a warning tone when you’re flying too slow and are at risk of stalling. I refer to it as a “system” because it’s it’s made up of a few components although it’s not that complicated. My hardware design resides in the plane but to complete the task it also relies on the telemetry capabilities of the Spektrum radio product line. The telemetry capability is key here because this is how the measured airspeed gets transferred from the plane down to the controller for your observation. The controller also allows you to program the minimum speed threshold, unique to your model, that will be used to sound the alarm (or vibrate the controller) if the speed drops to that level. That’s how the stall warning is implemented.

This system features the new airspeed sensor and associated hardware. Along with the Spektrum telemetry and transmitter features, it provides the following benefits:

1.       True airspeed readout on the transmitter’s LCD display range is 0-35 mph.

2.       An optional voice announcement of the airspeed at 5 or 10 second intervals

3.       A selectable warning annunciation when the airspeed drops below the user programmed minimum speed threshold. The alarm can be a combination of a tone, vibration, or voice message

Putting this system together will require soldering skills. Jumper wires need to get soldered to a few through holes in a pcb. The sensor cable needs to be extended since you can’t buy one that is long enough to run from the sensor out on the wing into the fuselage center section where it terminates at the electronic module that reads it. Also, you’ll need to have basic modeling skills that include fishing the sensor cable though the wing and mounting the electronics. 

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K & A Models OV-10 Bronco Build

The CAL FIRE OV-10 Bronco.

By Steve Belknap

Back in the early 2000s, our club (SEFSD) hosted a yearly event that we called the Mid-Winter Electrics.  It was a 2-day event that showcased the latest and greatest in electric powered RC planes.  There was open flying, demonstrations, etc.  We also had vendors that would come a long way to attend.  One of the regular vendors was K & A Models of Albuquerque, NM (no longer in business).  Ken Williams would showcase his expertly crafted kits.  I bought a few of them and recently completed one, the OV-10 Bronco.

It was a pleasure to build such a well made kit.  Everything fit perfectly.  The fiberglass work was second to none.  I made many modifications to mine mainly because I wanted more power, retractible landing gear and functioning rudders.  More details about these mods later.

I chose the CAL FIRE markings because I liked the look better than the typical camouflage you see on most military aircraft.  It turns out CAL FIRE has a whole fleet of these stationed all around California.  CAL FIRE uses the OV-10s as the primary command and control platform on wildland incidents.  I found there was one stationed at the Ramona airport so I modeled mine after that one.

Please see the video of the first flight.

The specs are:

Wingspan:  43.5″
Weight:  64oz
Power:  (2) Cobra C-2808-26
Prop:  (2) APC 8x6E & 8x6EP
Battery:  4S-3000 mAh Li-Po

The power system chosen makes about 600Watts.  This gives the plane 150W/lb.  During the first flight I was mostly using less than half throttle.  Performance was excellent.

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The Gallaudet Seaplane Project, Pt. 7

 

The Gallaudet’s First Hop off the Water.  Click below for a video of the first time on water.

By Allan Flowers

ASSEMBLY:

With this model, all the major components are separated from each other so the struts and rigging become the heart of the assembly process. It was necessary to design and construct a large wooden fixture to accurately hold things in place during this time. Rigging is multistrand .031” stainless wire from McMasters-Carr and each element had to be made and fitted individually. Sullivan rigging connectors and clevises provide adjustment – with 75 pound fishing swivels to keep the wires from being twisted. Better and much cheaper than turnbuckles.

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The Gallaudet Seaplane Project, Pt. 6

By Allan Flowers

WINGS:

The laser cut parts for ribs, etc. were the basis of the wing construction. This design has L-cut steel fittings at the strut & rigging locations. The main spars are 10mm carbon fiber tubes and there is a 3/4” wiring tube in each wing (thin wall aluminum on lowers, paper tubes on uppers).

The aileron servo housings were a special task and each one is wired with high capacity extensions and capacitors. I am using Hitec standard size servos (HS-645mg). Right hand wiring separate from left side to allow exponential throws. The wire leads eventually will be routed through junction boxes and into grooves on the insides of the cabane struts to the RX in the fuselage.

There is a triangular lifting frame on the upper wing, based on the Gallaudet D-1. Steel fittings for this were necessary in the top wing’s center area.

The Gallaudet Seaplane Project, Pt. 4

by Allan Flowers

FUSELAGE DETAILS:

The cockpit shroud was formed from aluminum sheet over a wooden form, annealed and bullied into shape with a dowel. It’s not perfect (first attempt was a failure) but the cockpit combing will hide the worst of it .

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The Gallaudet Seaplane Project, Pt. 3

by Allan Flowers

The REAR FUSELAGE:

Because of the unique power system, the rear fuselage must be supported on the central tube that the propeller hub rides on. A fiberglass tube is glued into the wooden structure to engage with the aluminum tube.


A narrow hatch gives access to the rudder and elevator servos and the linkages to two jackshafts that drive pull-pull cables to the control surfaces. It also provides a place for a bolt that prevents the rear fuselage from rotating on the tube.

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The Gallaudet Seaplane Project, Pt. 2

by Allan Flowers

Early CAD models, Etc.

There are multiblade propellers available in the size needed (e-Calc) but the hub would need drilled out for a nearly 2” diameter mechanical system. Therefore the propellers and hub would have to be hand fabricated. Not having the ability to NC mill the unit, it would have to be made largely of laser cut wood and aluminum sheet. The thing would have to hold together at up to 7000rpm without flying apart – so accurate balancing and mechanical strength were critical.


The early CAD designs were eventually married to the available components from McMasters-Car and B&B Manufacturing (maker of sprockets and belts).


The idea was to make and test the drive system before embarking on the rest of a two year’s long build.

Eventually an APC propeller was selected (22x10E) and two were purchased. These were fixed in a mold where resin collars could be cast around them. This element was cut off and finished. In the meantime, my laser cut metal and wood parts had arrived and the hub unit was assembled.

Using a crude wood test fixture, I determined the inter shaft distance between the sprocket centers. Later I was informed about a website calculator which verified my empirical test results to within .05mm.

As the hub was being created and balanced, it was necessary to design and build the forward fuselage portion, to complete the drive system. This would enable a test of the drive unit – a critical step to determine its feasibility. The system would have to produce sufficient thrust and not fly apart.

The hub unit needed to act as a fan to bring cooling air past the motor which, being located rather far back in the airplane, could be prone to overheating. The final part is designed as a centrifugal pump and should keep the motor fairly cool.


As the CAD design progressed, other components were being finalized for fabrication. One item was the nosecone which was a challenging part to make. Ultimately a 3D printed part was made by Thomas White, a prominent scale modeler on the East coast who has large scale 3D printing capability.


The fuselage was built around the aluminum tube upon which the propeller would run. The forward part was completed and the tube, motor and drive system installed for testing. I needed a “test sled” to hold everything and allow thrust measurements to be made.



The laser cutting included the floats and rear fuselage parts so I moved ahead with those things while finishing the front fuse. Used extensively throughout was a .01” resin composite sheet (brand name – Fliteskin). This is a waterproof, very strong sheet material assembled with expanding Gorilla Glue. It is light enough and nearly bulletproof. I tried to economize on the wood structure but the weights are still a bit more than desired.

 



One necessary study involved how to transport a finished RC airplane in my little car. After making a rough model of its interior, I could digitally maneuver the plane model into the “car”.

Allan

T-28 Front Landing Gear Repair Buletin 05-12-2023

You are probably not like me. You can probably land one of these T-28’s without buggering up the nose gear.  I re-glued it a few times .  It was beyond re-gluing as the foam gets a bit soft after repeated beatings with terra firma.  The plastic insert was fractured in 2 places as well.

 

The red arrows show fracture stress points at sharp edges of the plastic molding.  Note also, the oil  covered belly.  These round engines ALL leak  😉

 

So I made a scarf plate out of .063″ 6061-T6 aluminum as I did not have any 2024-T3 around.  Hey, it’s what I had!  It’s pretty small so it does not weigh much.  Kind of a hack job but, it does the job of spreading the loads out to undamaged airframe foam.  Note the screw hole.  This helps couple the load from the plastic molding.

 

Scarf plate attached.  Note I cut away some foam on the starboard side to match the port side.  Note the screw.  I used a bead of silicone around the perimeter to spread the load from the flat aluminum to the uneven foam.

 

The back lighting made this picture difficult. Note that there is a gap between the nose strut and the aluminum scarf plate.  I’m sure this will be bumped into on landings and take the load off of the broken, glued, beat up plastic molding.  If you zoom in you can see the bead of silicon glue.

So, we’ll see how well this holds up and hopefully it won’t form any more stress concentration points. 

See you at the field,

Bob K

The Gallaudet Seaplane Project, Pt. 1

 

By Allan Flowers

This project started almost a year ago on a Google Image search when I discovered a very strange and interesting airplane. Having been thinking of starting a new project, I was intrigued by this odd challenge.

The Gallaudet was powered by a mid fuselage propeller driven by a ring gear – by no less than twin Duesenberg engines. The first version of this design, the D-1, actually flew in 1916 and was a proposal for the US Navy, which subsequently commissioned the Gallaudet Company (Connecticut) to build two more, the D-4s. One later crashed when the propeller failed, killing the test pilot. The other flew for several years, ending its life as a Schneider Cup racing plane. These were quite large planes, with wingspans of about 48 feet.

My first design was to be 1/6th scale at 96” WS. Along with the issue of the unusual drive mechanism, the ability of the single main float to provide sufficient buoyancy for a 20lb model was a concern. My CAD program has a mass properties function but it wouldn’t give me consistent answers so I solicited some help from fellow modelers on RCSB where I had started a “build thread”. Based on their calculations, combined with measurements of my Scion (which had to be used to transport this thing), I decided to consider a different scale. Around this time, a gentlemen who had seen the build thread, sent me some info from WW-1 Aero Magazine, which showed a drawing of a smaller Gallaudet proposal for a “hydro scout” (also from 2016). It had a 28 ft WS and larger a tail-fin and ailerons. This plane could be made in quarter scale with a larger float but smaller wingspan than the D-1.

The United States was soon involved in WW-1 and lost interest in the hydro scout programs. Thus the Scout was never made but the drawing had enough detail to interest me in a build.

The early CAD designs established the parameters of the drive mechanism and enabled a search for components, mostly from McMasters-Carr – which provides CAD models to download and pop into my system. The main parts were the roller bearing and sleeve which could be slid over an aluminum tube which would join the front and rear fuselage sections. Also important were some thrust bearings and seals to complete the drive.

Next was finding sprockets and belts to power the thing, and a suitable electic motor of small enough diameter to fit in under the main aluminum tube. That boiled down primarily to a few Hackers and Neumotors. The final choice was a Neumotor driving 13 and 44 tooth sprockets through a 15mm belt. Because of the gear ratio, a high KV motor was a necessity. E-calc was very helpful in researching the motors, ESCs and propellers. The later was a big challenge because there are no multiblade props that would work with the unusual hub design.

Jovi’s DC-3 Build Project: Chapter 3, Building the Wing

By Jovi Murek

Hello again, well I’m back at it and building up the DC-3 Wing for this chapter. In this step, we will build up the center section of the wing. This aircraft was designed for nitro engines and, as you know, I am going to convert to electric.

Building the center section required a few modifications needed to be done first. W3 rips required cut out for the retracts, Firewalls got completed with the blind nuts installed. Other changes were needed, but just not now. So, I laid out the Center Spar and glued on the Ply Center Spar together once it cured. Next was to test fit the four plywood ribs and fit it to the building plans. From here I fitted the remaining ribs and fitted the wing mount block and the blocks for the retracts. Next was to fit the TE, (Trailing Edge). In the next few photos, you can see how it was all done.

 

Now that it all fit correctly and was flat on the building board, I was ready to glue, however, now that I see how it fits, I took it all apart and was ready to modify the main spar to except the retracts. Close to the outer ends of the main spar, I had to remove a section of the spar on both sides. This allowed the mechanics of the retracts to fit. The Top and Bottom spruce spar would be the strength to hold the cut-out section of the main spar. Alone with two strips of 1/16 plywood attached to the spar over the area of the modification to the spar.

DC-3 Fact:
The DC-3 was not only larger than the DC-2, but also much easier and safer to fly. An automatic pilot was installed as standard equipment. The overall design of the DC-3 was so successful that its basic specifications were never changed. Once the first DC-3’s entered service, the speed at which the entire industry converted over was limited only by the rate at which Douglas could produce them.

It was time to put it all back together and test fit all the pieces to make up the center section of the wing. Once I looked it over, and everything was just perfect, I started to glue the parts together with CA glue. Let it sit for a while, (just to make sure) I then added the TE and added some rails to the wing. I also added the dowel pins in place, motor mounts for the retracts. Ok, center section was coming together, as shown:

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A Multiplex Mentor Testbed for Year 2020

A Forty Size (Test Bed) Standard Electric RC Airplane

By Carl Murphy

Introduction

This article begins where all the rest of the articles, tests of as specified by the manufacturer and flown only a few flights, ended.  Real world flying, where parts fail, break, wear out, fly off or don’t match the specifications.  Not shiny new hopes with failures censored out, and, what it costs, the net cost per hour of flight.  Follow along and try these easily available combinations for yourself.  And why I have been declared a bad example where ever I fly by Radio Control.

Before ever starting make sure the airframe is set up right, with components that last, then begin the tuning of the propulsion.  The setup of of the airframe follows.

By propulsion we are describing the whole package, motor, propeller carrier, propeller, motor-controller (to include any internal programming) and battery.  They have to match a specific RC airframe, location and flying style.  Ten motors were flown, seven direct drive outrunners, three geared inrunners, varying the input voltage from 3S LiPos through 5S and matching the propellers.  Several more motors, some defective, some obsolete, were rejected after bench tests.

Some combinations were later flown in more suitable airframes, see the parallel Fun Cub and the economic comparison of outrunners verses inrunners articles.

If you read a vast majority of magazines articles and their Internet equals, with the exception of competition machines, matching propulsion to the airframe is a neglected art.  You get an entirely false interpretation that the author chose, and demonstrated, the best, on the first try.  It becomes a form of censorship by omission not comparing equipment.  And the tests don’t go long enough to demonstrate stuff wearing out.  I haven’t even decided on the center of gravity or control surface throws at three flights, they are publishing everything is great at that much/little experience?  Which has led to the current acceptance that cheap equipment is just as good a real, no risking a quality/efficiency comparison.  Although many can set a motor-controller for braking the propeller to a stop when in-flight with the motor off, as for setting the motor-controller timing, it’s which-craft (zu Deutsch Wechseleri) to most.

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Bill’s Deltas

Bill Allen has been a club member since the 90s and loves delta wing jets.  He’s made the coolest jets from some of the most mundane materials.  His early jets were made from Dow Blue Foam and the recent jets are now made from $1 Foam Poster Board.  Below are some of his creations from the last 20+ years:

 

Blue Foam A4, 2004

 

How some of them were launched in 2001.  Piggy backed on my Sig Kadet Sr. (Big Red).

 

Late 90s Skyray delta pushers.

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JR Models Cessna Skymaster Build

This will be a brief description of my JR Models ARF Cessna Skymaster build.  Although the kit was made in the mid-90s, in the Czech Republic, I only built it in 2021.  I bought it from Fred Harris many years ago at one of our club swap meets, along with the JR Models Mosquito I built and wrote about previously.

I took no pictures during the build so I’ll supplement with pictures from the finished plane.

The entire instructions.

First, I present the highly detailed and thoroughly informative instructions.  Yup, that’s it, all you get.  Much creativity was needed putting this plane together.  Although the instructions were minimal, the fiberglass work and wing builds were exceptional.  The equipment placements shown are a mere suggestion which I mostly ignored.

The main fiberglass parts of the kit are shown on the drawing near the title box.  You can see a fuselage with stub wings and two tail booms with rudders.  The wings and horizontal stab are prebuilt out of balsa and covered.  A hardware package was included.  Formed windows and landing gear were also supplied.

Wingspan:  49″
Length:  36″
Weight w/LiPo:  3lb 11oz

Wings

Wing Joiners: Original brass tube replaced by a longer carbon tube.

This plane was designed to be powered by two Speed 400 brushed motors.  That would only give the plane about 100 Watts of total power.  I wanted to use more like 300-400 Watts of brushless motors.  The wings did not have any kind of spar, just ribs and balsa sheeting.  This required more substantial wing joiners than the short pieces of brass tube supplied.  I used much longer carbon tubes.  To get them further into the wing structure, I needed make holes in two more of the ribs.  I sawed teeth on the end of the carbon tube and used it like a hole saw to drill through the ribs.  Slow going but it worked.  The longer joiners also made it possible to have the wings removable.  Tape was wrapped around the carbon joiners in a couple places since they were too small for the holes in the fuselage.

The wing servos were a simple job to install.  Hinge tape was used to attach the ailerons.

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Brian’s Huge Amazing 95″ Spitfire

The wait for my dream Spitfire is over.

After having and flying my 80” Phoenix Model P47 for a few months (my biggest warbird at the time), in May 2021, I decided to try something bigger, I ordered a 1:4.75 scale Spitfire (95”). It is also Phoenix Model and distributed by Tower Hobby. Unfortunately, it was on back order and estimated to be shipped in a couple of months. But they have been changing the shipping status month after month, and it is still on back order now.

While waiting for the Spitty to come, I spent time to collect all the electronics and power components for it. I also bought an 80” Black Horse Spitfire from MotionRC (it is still in boxes, a backup plan if I don’t ever get the 1:4.75 scale one).

Then, in mid-September this year, as I almost gave up waiting for the 95” Spitty, and was about to start on the Black Horse. I found on RCGroups, someone in Riverside who had 5 flights on a 95” Spitty ready to fly for sale. I was so excited and, after exchanging texts and messages, the wait is over! I went to Temecula and brought my dream Spitty home.

The plane was equipped with all Hitec HS-645MGs which are analog servos. I changed them to digital D-645MWs except for the rudder, I used JX PDI-6221MG for more torque and less expense.

I also custom made 9 pins quick connectors for the wings and fuselage (picture below).

Here are the specification and setup of the Spitty:

Length:                86” (2184mm)

Wingspan:            95” (2413 mm)

Motor :                 Rimfire 65cc

ESC:                    Castle Phoenix Edge HV160A

Propeller:             Xoar 23x14x2

Spinner:               Falcon 6”

(I will change them to Biela 24x10x3 and also Falcon 6” spinner for more scale)

Battery:                 2x 6S 5000MAh 55C in series (12S)

                             2x 2S 2200MAh LiFE for receiver

                             1x 2S 1000MAh for retracts

Servo:                    6x Hitec D-645MW (2 Aileron, 2 Elevator, 2 Flap) and 1x JX PDI-6221MG for Rudder.

Radio:                    Tx: FrSky X10S Express (2.4GHz) + R9M 2019 ACCESS module (900MHz)

                             RX: Archer SR10 Pro (2.4GHz) + R9 Stab OTA (900MHz) in redundancy

(In case the main RX browns out, the long range R9 will take over)

I went over and double checked everything.  Then came the exciting and also scary Sunday! The maiden day!!!         

Compared to the weight and location of the batteries (8000MAh) from the previous owner, I use much lighter batteries, but it was still nose heavy (picture below, thanks to Fredrick and Brad!). I decided to maiden it with nose heavy since the weight of the nose was reduced quite significant compared to the original setup from the first owner.

Thanks to Fredrick Lorenz for helping as a wingman in my maiden flight, and also so sorry to folks down the runway, as the Spitty created a big cloud of dust when I tested the power before takeoff.

When the plane lifted off the ground, as expected, up elevator trim was needed, also right aileron. After less than a couple laps of adjusting, it flew straight. Although, I had too much throw for elevator and ailerons so I had to adjust my thumbs movement during the maiden flight.

After the maiden flight, I moved the batteries further back and achieved the CG marked by manufacture, and reduced the throws. The Spitty seems to be happy with that. It almost flies inverted without down elevator.

Thanks to Lewis Dotson for perfectly captured both of my flight videos! Links of videos below.

Also pictures from Tom Gluggio, Pete Kwei and help from other friends!

Happy flying!
Brian Zhuang

Maiden flight:        https://youtu.be/LbpRA-AB4gw

Flight #6:              https://youtu.be/UQSIbAmVGgw

Spitfire landing:     https://youtu.be/6Tv2MEfOHlk

P47 landing:         https://youtu.be/DOhqsAPyBTc

Mark’s Big Beautiful Jet

The plane is from HSD Jets, and runs on four 90mm fans.  I fly with 4 batteries of 6S x 5000mah. The length is 118 inches, and scale is 1:23.  For comparison, attached is a photo of me standing next to the fuselage.
This plane is easy to control in the air, but difficult on the ground.  The nosewheel has very little steering authority, and there are brakes on only two of the 18 wheels.  So that’s pretty close to not having brakes.  I first flew it up at Hemet, and even there I over-ran the end of the runway.
Then I took it up to the “Best in the West” jet rally.  This takes place on a 3300ft runway, so I was able to complete many flights with no problems.  It was super popular there, even though it is not particularly large or expensive by BITW standards.   The first BITW flight was captured in this video:
I ended up winning two trophies at BITW, “Best EDF” and “Best Civilian Jet” (photo attached).  I would like to bring it to SEFSD sometime, but I think it requires some modification to do that.  Thrust reversing on two nacelles would do the trick, but I’m not sure I will get around to it any time soon.
Mostly I just flew docile flights, although after a few I got a little braver and did several banked passes (45-degree-ish partial knife-edge) along the flight line.  And on the final flight, I managed to sneak in a barrel roll.  
Thanks to Bob Stinson for helping me schlep it up to Hemet for the first flight, thanks to Victor Shamulus for the video, and thanks to Andy Davis at HSDJETSUSA who fedex’d a replacement servo to me the week of the event, which enabled me to fly it at Best in the West.
Thanks,
-Mark

Otto Steals the Show with his RC Loon!

Flyguy Promotions received a contract from Wide Angle Group in early June to produce a 10 foot flying Loon based on the Minnesota United Loon logo. The Loon was flown as part of the Major League Soccer (MLS) pregame covered by ESPN. Mike Frandsen, Bob Simon, Dave Encinas and Otto Dieffenbach built the Loon in 5 weeks with first flight on July 10. Emily DeJoode, Manager of Ampdraw Hobbies in Encinitas joined Otto as his far corner spotter for the performance. Three rehearsals and the performance flights were flown on August 8, 9 and 10. FAA and FBI approvals were obtained prior to flight operations.

The performance and project were considered great successes by ESPN, MLS and Minnesota United. 

Jovi’s DC-3 Build Project: Chapter 3, Building the Lower Section of the Fuselage

Now that I have completed the top section it is time to move to building up the lower section of the fuselage.  In this process we will also be making a change to the build.  That is moving the servos back to the original position (behind F5 to F7) which was just over the wing, where I had made the hatch for the access to the battery.  You can see that in the drawing.

Ok, let’s get started in building the bottom section.  The first thing I did was to install the formers into place, making sure all were 90 degrees from the top stringers which were pinned down to the board when building the top section. The wing saddles were also installed at this time too.

At the same time, I installed the push rods guide tube into place.  I installed the servos and worked on the push rods to the correct length.  Once that was completed, I placed the tail wheel support plate in place for a dry fit and made sure that I did have the correct length. As always it was perfect. 

To make sure that it was correct, I connected the servos to my receiver and made sure the control arms were center.  I then completed the rudder and glued in the rudder block to the control rod and again made sure that all was center so I would not have to do it at a later time.   The elevator was done the same way, but I have not glued it yet into position.  If adjustments need to be made, I can do that on the radio.

DC-3 Fact:

The one and only DC-1 served a full career with TWA, then was sold to Howard Hughes.  Hughes sold the airplane to the Spanish government, but the DC-1 met its demise after an engine failure during takeoff in the 1940.   (Guess they didn’t read the “Engine Out” section in the manual)

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Jovi’s DC-3 Build Project: Chapter 2, Building the Top Section

Framing the fuselage Top:  Fun part about building Top Flite kits is that you build right off the drawings. Got wax paper, laid it down and I grabbed all the formers including grooved main stringers.  These two stringers I soaked them in water to create the fit of the curve for the nose of the aircraft.  Pinned it to the board and let it sit.  I also installed the cabin crutch to help form the main stringers.  Once that was done, I then completed pinning down the stringers to fit the drawing.   Next was to place the formers into place just to fit, but not yet glued in place.  Here is where I had to create a hatch for the battery, instead of taking the wings off like I have to do with my Cessna. I replaced two formers.  The formers that come with the kit are 1/8” So I will be replacing them with a ¼ “thick.  These two formers will be used for the opening of the hatch.  The formers that came with the kit are going to be used for the hatch as you will see in this process.

DC-3 Fact:

Without a modern passenger plane.  TWA was not about to let United Air Lines corner the entire market with Boeing’s 247.  TWA initiated a program of their own to develop a modern airliner.  Douglas responded with the most advanced and the most controversial design, namely DC-1.  TWA ordered one unit and in 1933 the first DC-1 rolled off the assembly line in Santa Monica, California.  The DC-1 was bigger and sleeker than any other liner in the industry, including Boeings Model 247!

As you can see in the above photo how the formers were fitted into position.  Starting with the nose of the aircraft is where I started to glue the formers in position.  For the hatch section as I mentioned I am changing the formers with ¼ “thick.  I then cut the two original formers and glued the lower section to the replacement ¼ “formers.  The top half will make up the hatch.  In between the two ¼” formers I cut the middle former to match the hatch and the bottom part, I cut out the middle and only used the sides, also show in the photo.

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Jovi’s DC-3 Build Project, Chapter 1: Stabilizer, Fin and Rudder

By Jovi Murek

Hello Club members, Here I am getting ready to start to build the DC-3.  Starting off with the tail section of the aircraft.  The first part was to make the skins.  Here I took two sheets of 1/16 x 3 x 30 and glued the two sheets to together so the outcome would be 1/16 x 6 x 30.  I created three sheets, two for the stab and one for the fin and rudder.  Now starts the fun part, building!   Now that we have gotten the skins ready, I’m starting to build the Stabilizer.  As show in the picture I have all the parts laid out on the building board and preassembled them before gluing them into position.

DC-3 Fact:

After presiding over various projects including the Matin MB-2 bomber at the Glenn L. Martin aircraft company, Donald W. Douglas Jr, born April 6, 1892, co-founder the Davis-Douglas Aircraft Company in the spring of 1920 with help from David Davis, a millionaire with a great desire to fly.  By the mid 20’s Douglas designs were well known throughout both the civilian and military aircraft industry.

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RC Kites

By Rob Jahnke,
“I have another RC kite I was planning to bring this year. I call it the RC Eagle which is the Revolution Eagle kite created by Joe Hadzicki of Revolution Kites. It has an 8ft wingspan and is powered with a 3S 1500mah Lipo but packs up into a kite bag. You can see the first test flight here: https://www.youtube.com/watch?v=NYhJ2Ij3mDw&t=75s
For the Revolution Eagle kite story check it out here:
The details of the RC Eagle Build are shown in this photo album. 
I make good use of the 3D printer for this project. I am happy to share the stl files.

Scaling and Comparing Performances of Aircraft Models (2D/3D Wing Loading)

[This article was borrowed from the April issue of the Ampeer.  Thanks to their Editor: Ken Myers]

By Andrej Marinsek

1. Introduction

Many years ago (Model Airplane News, Dec. 1997) an article was published in this magazine titled “3D Wing Loadings” (Three dimensional wing loadings) by Larry Renger; it was recently published again on the internet in a slightly cleaned up version. Its different approach to a specific modeling subject is interesting but, as it will be shown later, has some problems. The concept of the 3DWL, though correct in one respect, has otherwise rather limited reach and leads to some vague interpretations and questionable conclusions. The 3DWL persists around in different forms and publications and seems to be, nowadays, the most advertised and supposedly even the only appropriate approach for estimation and comparison of some model performances. This is somehow surprising, so it needs to be addressed in some way.

2. General remarks

Coherent units from the International System of Units (SI) are used in calculations as they are clearer. In most cases only one unit is attributed to a certain physical property and numerical transformations are simpler or not needed at all.

Instead of the term weight (W), which is strictly speaking, a kind of force, the expression mass is used (designated by the letter m), which is the proper name for the physical property measured in kg (lb., oz., etc), and is employed in all calculations here.

3. Agility of models

The motion of models in the air can be on one side described by the words like “agile” or “hot” or “docile” or “flyable” or whatever expression is used to appreciate the performance of models in flight. However this can be pretty undetermined and subjective.

On the other hand, some objective (given by numbers) performance parameters exist. With regard to the lateral axis of models, some performances directly depend on the lift force. These are the minimal speed in horizontal flight vm (stall speed), the minimal absolute turning (or circling) radius Rm and the minimal relative turning radius (RTm), which will be defined and discussed a bit later.

Also, some settings (such as the center of gravity) and a number of model properties, for instance wing profile, low/high wing, aspect ratio, tail (distance from the wing, area, position), the size of rudders, propulsion, thrust vectoring, etc. considerably affect certain performance parameters.

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