Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => Building / Construction => Skywriter Scratch-build Class => Topic started by: Michael on March 14, 2014, 08:31:34 PM

Title: Michael's Skywriter build thread
Post by: Michael on March 14, 2014, 08:31:34 PM
I'm starting my own thread for my construction of the Skywriter biplane.

I'll post images as I move along, and point out deviations from the plans or instructions.

Any changes I make are for my own personal building preference, and should not be considered better or worse.

Some of these changes might be to save weight, make building easier, or maybe because I'm lazy and I found a way to do things faster.

First, the rudder and fin have been built and partially sanded. First deviation from plans: the fin is sheeted with 1/32nd balsa instead of the supplied plywood.

Starting the stabilizer /elevator.
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 14, 2014, 08:35:59 PM
Elevator and stabilizer are built, sheeted with 1/32nd" balsa instead of the supplied plywood, all sanded, the elevator halves joined with a wire, and hinged (hinges won't be glued until after the model is covered and partially assembled).

The cut 1/4" sheet parts in the stabilizer are slightly different than what is shown on the plans.

The 1/32nd sheet is delicate once glued on; I broke through it with my thumb during sanding, and then repaired the hole.

The built rudder/fin weighs 15 grams.
The built elevator/stabilizer (with wire joiner) weighs 52 grams.

I'm only posting weight because others are in other threads.
I don't normally keep track of details like that.

Title: Re: Michael's Skywriter build thread
Post by: sihinch on March 17, 2014, 08:04:11 PM
I'm worried that my elevator joiner is too flimsy.  What size/gauge or wire did you use, Michael?  Is there any flex in it?
I may be adding carbon rod to mine!
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 18, 2014, 10:16:45 AM
I used 3/32" wire.

Carbon-fiber rod, if glued on to both halves securely, would probably be OK.
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 29, 2014, 06:25:26 PM
Lower wing under construction.

I will be using an extremely simple method of mounting aileron servos; see the image.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on March 29, 2014, 07:20:42 PM
Looks great! I started mine and am upset because I think it's crooked!

Piker? Frank? Help!
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 30, 2014, 04:07:41 PM
Lower wing construction completed.

Still to do:

1. plywood wingbolts support

2. more sanding

3. aileron control horns.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on March 30, 2014, 04:14:08 PM
Hey, that's cheating! You went passed the homework assignment!
Title: Re: Michael's Skywriter build thread
Post by: piker on March 30, 2014, 05:35:30 PM
Yes he did.  He can't control himself.


He'll have to sit in the corner during next class
Title: Re: Michael's Skywriter build thread
Post by: piker on March 31, 2014, 11:33:41 AM
Hey Michael and others,

Did you guys remember to include the FORWARD wing joiner, on the front of the spar, at the center section of the wing?  I don't remember seeing it on anyone's build yet.
Title: Re: Michael's Skywriter build thread
Post by: Papa on March 31, 2014, 01:06:49 PM
I did, it was buried in that box I made for the dowel.


Also don't forget the scrap filler at the TE for the mounting bolts!


Also don't forget the 1mm ply on the bottom of the TE at the centre!


Jack.
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 31, 2014, 03:29:10 PM
My forward wing is joined by glue.

I don't know what you're talking about; I'll check the plans at home tonight.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on March 31, 2014, 03:57:21 PM
Frank will be showing us those bits this week, right Jack?
Title: Re: Michael's Skywriter build thread
Post by: Papa on March 31, 2014, 04:26:42 PM
Right Simon!


Jack.
Title: Re: Michael's Skywriter build thread
Post by: Papa on March 31, 2014, 04:35:35 PM
What Rob is referencing is a cross piece that seats the dowel and braces the wing joints.


Jack.
Title: Re: Michael's Skywriter build thread
Post by: piker on March 31, 2014, 04:40:52 PM
Yes, I'm talking about the smaller dihedral brace attached to the front of the spar.
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 01, 2014, 05:28:58 PM
OK, now that I bought the Albatross kit from Colin, I want to try to speed up this project so that I can finish it first.

As suggested by Jack, I'm building the kit as close to the plan design as possible.

One change I'll be making is to lengthen the nose by a couple inches, but other than that, I'm building the fuselage as recommended.

I decided to build the fuselage before the top wing, because I'll find it easier to put together the struts and fittings to attach to the upper wing.

I was going to go flying, but because it was so windy and cloudy, I stayed home and built a good portion of the fuselage.

I'll stop by a hobby shop tomorrow and look for a motor, ESC, servos and maybe some landing gear to suit.

Once I have the motor, I'll figure out how to customize the fuselage front/cowl.

Title: Re: Michael's Skywriter build thread
Post by: piker on September 01, 2014, 07:53:55 PM
Wow!  You're FLYING along!  That looks great!
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 02, 2014, 09:15:15 PM
I 'cheated' and read the "end of the book".

According to the final instructions and pre-flight information, the model was tail heavy and needed nose weight, and the battery hatch was too small and had to be modified.

I had mentioned I was going to lengthen the nose a bit, and here's what I did that should help solve both those issues somewhat.

I moved the motor-mounting firewall forward until right behind the round plywood base for the cowl. This moves the motor forward about 1¾", and allows that much more room for the flight battery. The attached photo shows this, and the X-acto knife is in the position where the firewall was supposed to be.

Also, I will not use thick balsa at the rear bottom of the fuselage. I will probably put some cross beams, and a few other pieces, and leave the structure open. It will be covered with film covering anyway.

The motor shown is a 1000KV motor that can use 3 or 4 lipo cells.
I'll be using a 60 amp speed control.
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 06, 2014, 06:18:49 PM
Well, since the float flying was cancelled for today, I started charging batteries to go fly at TEMAC tomorrow, and I spent a few hours on my Skywriter.

The upper wing has been started, and I did more work on the fuselage: motor mounted, front fuselage sheeted, lower rear fuselage with 1/8" cross beams and edges, cowl started, lower wing bolts installed, upper wing aluminum supports installed, landing gear installed including steerable tail wheel.

The slightly longer nose does not seem to affect the noticeable shape of the plane.

Note the lady pilot.
Title: Re: Michael's Skywriter build thread
Post by: Papa on September 06, 2014, 06:50:00 PM
She's called the Lady Lynn EH!


Jack.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on September 06, 2014, 08:34:20 PM
Looks great. So you're not coming to class this year then?! Lol

Can I ask, have you made the wing tips flush with the underside of the wing?
Title: Re: Michael's Skywriter build thread
Post by: piker on September 06, 2014, 08:46:18 PM
Michael's an over achiever! 


I bet he made airplane noises today   ;D
Title: Re: Michael's Skywriter build thread
Post by: sihinch on September 06, 2014, 09:42:01 PM
And did you make your struts and undercarriage?
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 07, 2014, 08:24:36 AM
Simon. the wingtips run from the center of the trailing edge to the center of the leading edge, with supports on top and bottom.

The cabane struts were bent from 1/16" x 1/2" aluminum rod purchased from Loews. It was easy to do; I used a pliers to bend it nearly to perfect shape.

The undercarriage was bought at the hobby store.
I have another set that I can sell cheap, if you or anyone else wants.
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 09, 2014, 08:42:55 PM
I did a little more work on the fuselage.

Top sheeting is done, as is the large battery hatch, which is the full width of the fuselage, as opposed to the half-width shown in the instruction manual, and longer due to the longer front section I customized. (The instruction manual does show a larger modified battery hatch on one of the last pages.) The battery hatch will probably be held down with magnets.

The open cockpit sheeting is done, and the wood instrument panel is in place for the photo, but not yet glued.
The 'combing' on the cockpit sheeting/opening will be made of split black insulation from old coaxial wire.

The bottom rear of the fuselage was finished with 1/8" thick framing instead of sheeting.
In fact, if one wanted, the entire fuselage could be of openwork construction instead of sheet/slap sides.

I'll work on the tail area soon, and then finish the top wing.

Then the whole model will be sanded smooth, the radio equipment will be installed, and then covered.
I'm still undecided on colours.
Title: Re: Michael's Skywriter build thread
Post by: Papa on September 09, 2014, 09:35:46 PM
Looks Good.


Jack
Title: Re: Michael's Skywriter build thread
Post by: sihinch on September 09, 2014, 10:52:15 PM
That's beautiful, Michael.
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 18, 2014, 07:59:17 PM
More construction progress:

1. Tail fairing finished.

2. Airfoil shaped aluminum wing struts.

3. Upper wing finished.

I'm going to construct the windshield next, and make sure it can be installed more securely then simply being glued on.

Then: sanding, radio installation and covering.
Title: Re: Michael's Skywriter build thread
Post by: Frank v B on September 18, 2014, 10:28:39 PM
Michael,  Looks great. 
You have just been promoted to instructor. :)




Frank
Title: Re: Michael's Skywriter build thread
Post by: piker on September 22, 2014, 02:19:27 PM
Yes!  Looking very good!

I was just speaking with Michael and told him to hold off covering until later, so he can bring the framed model to the next meeting.  We'll see if he can resist   ;D
Title: Re: Michael's Skywriter build thread
Post by: Wingnutz on September 22, 2014, 07:36:03 PM
Michael,
Do you ever slow down? Impressive progress!
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 24, 2014, 09:16:54 AM
Can't control myself; ready for covering!  :o


Had some fun and did the dash/control panel.



Title: Re: Michael's Skywriter build thread
Post by: piker on September 24, 2014, 09:42:06 AM
 ;D

It's a good thing you have those high tech orientation instruments.
Title: Re: Michael's Skywriter build thread
Post by: Papa on September 24, 2014, 09:45:43 AM
He needs them, he's growing more forgetful as he ages.


Jack.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on September 24, 2014, 09:49:40 AM
I think he has too much time on his hands!  ;)
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 28, 2014, 07:20:13 PM
I brought my 'almost finished' Skywriter to the Skills Challenge event today, and a few people asked me how I modified the forward fuselage section to make it longer.

1. I glued the firewall right up (forward) against the front former which was to be the base where the laminated cowl was to be glued. See photo 10. The plan position for the firewall is where the X-axto knife is sitting on the fuselage, in that photo.

2. I glued additional 1/4" pieces of balsa on the front of the fuselage sides, the length taking into consideration the length of the motor I'm using and the laminated balsa cowl. This will vary depending on the motor you choose to use. See photo/diagram 10a. I glued the cowl in place after making sure the motor and motor mount fit.

3. I used the bottom fuselage 1/4" sheet with the air cooling vents as per the plans, but added a bit more 1/4" balsa at the front to fit the longer nose to the cowl. I sheeted the fuselage as per the plans, but with longer pieces of balsa to fit. Everything was later sanded to look proportional.

Feel free to ask questions.

Title: Re: Michael's Skywriter build thread
Post by: Michael on September 28, 2014, 08:43:42 PM
More progress.

The model has been covered in white Monokote (heat-shrinkable and heat-activated adhesive plastic covering); decorations and decals will follow.

Rudder and elevator servos and linkages installed. There are supports for the flexible pushrods at every former.

Simple tail wheel and linkages at the tail. I used a commercial tail wheel mount with a set screw/collar to hold the wire lower than the rudder, and an elastic as a shock absorber to the rudder, for steering control.

Black insulation from old coaxial wire is used as combing around the cockpit. I cut out an approx. 1/8" strip from the insulation to make the fit easy.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on September 28, 2014, 08:57:06 PM
Question about the motor firewall....


Is it strong enough how it fastens to the sides of the fuse? Just some sheet and 2 horizontal rods?
Title: Re: Michael's Skywriter build thread
Post by: Michael on September 28, 2014, 09:04:57 PM
It's also glued to the back of the circular plywood piece which is also glued to the sheet sides and 2 longerons.

The upper and lower sheeting also add strength.

It seems strong enough to me.

Title: Re: Michael's Skywriter build thread
Post by: Michael on October 01, 2014, 09:37:00 PM
Aileron linkages.

I used "1/2A" control horns securely glued into/onto the ailerons, connected by Z-bend/threaded rod/clevises.

Title: Re: Michael's Skywriter build thread
Post by: Michael on October 01, 2014, 09:38:37 PM
Decals left over from other projects.

Pilot figure mostly repainted with matte acrylic paint.

Title: Re: Michael's Skywriter build thread
Post by: Michael on October 01, 2014, 09:40:46 PM
Still to do:

- windshield

- balance (needs nose weight even with battery).

- measure power draw

- adjust dual rates and exponential.

Title: Re: Michael's Skywriter build thread
Post by: piker on October 01, 2014, 10:18:45 PM
That looks GREAT, Michael!, oh and I like the aileron linkage idea.  Very solid.


Although I've given you grief for building ahead of the class,  ;D   It IS inspirational to see one of the Sky Writers finished and ready for flight.  That'll help the rest of us keep motivated to finish for the spring.


Hmmmm.... All I've done is framed up the tail feathers.... Time to get back at it!  The next build class is on Monday   :o
Title: Re: Michael's Skywriter build thread
Post by: sihinch on October 01, 2014, 11:03:03 PM
That looks AWESOME! Congratulations. Definitely motivation for us class mates.

And I may copy the aileron idea!
Title: Re: Michael's Skywriter build thread
Post by: Michael on October 02, 2014, 08:52:20 AM
Just remember, despite my efforts to build lighter at the tail, and the longer nose, my model is still slightly tail heavy.


Build accordingly.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on October 02, 2014, 09:46:57 AM
Or go 5S  ;D
Title: Re: Michael's Skywriter build thread
Post by: Papa on October 02, 2014, 09:55:38 AM
5S, that would guarantee a built in smoke unit. @Michael


How much weight did it need?


Jack.
Title: Re: Michael's Skywriter build thread
Post by: Michael on October 02, 2014, 10:17:45 AM
IMO, the plane will fly just fine on 3 cells, and very well on 4 cells.


IMO, a 5-cell lipo battery pack would be redundant.


My plane balances almost perfectly with a 4S 5000mah pack, but it's too tight.


It will need about 5 ounces in the nose with a 4-cell 3850 pack.


I'll verify within a day or two.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on November 25, 2014, 10:05:31 AM
Hey Michael, would love some help.


I'm just finalising my motor choice and want to get an idea of what a finished Skywriter weighs, ready to fly.  So all-up-weight with battery.  Can you help, please?


Want to know how many watts to plan for....
Title: Re: Michael's Skywriter build thread
Post by: Michael on November 25, 2014, 10:14:40 AM
I'll weigh it tonight.
Title: Re: Michael's Skywriter build thread
Post by: Michael on November 26, 2014, 07:23:35 PM
Somewhere between 5 pounds and 5.4 pounds, with battery and balancing lead.
Title: Re: Michael's Skywriter build thread
Post by: sihinch on November 26, 2014, 09:11:13 PM
You're a gem! Thank you.

So somewhere around 500-600watts is required!
Title: Re: Michael's Skywriter build thread
Post by: Michael on March 25, 2015, 06:43:53 PM
Spinner added for looks!  ;D
Title: Re: Michael's Skywriter build thread
Post by: Papa on March 26, 2015, 07:57:40 AM
Looks great. I'm going to do the same with mine.


Jack.
Title: Re: Michael's Skywriter build thread
Post by: piker on March 26, 2015, 11:34:20 AM
I assumed, when I saw a fresh post about Michael's Skywrtter, that he was going to say the test flight went well!   ;D  The weather there must be getting nice for flying!

It's really nice here in San Diego.  I wish I had a seaplane with me...
Title: Re: Michael's Skywriter build thread
Post by: Michael on May 09, 2015, 05:14:15 PM
The test flight went well!

;D
Title: Re: Michael's Skywriter build thread
Post by: piker on May 09, 2015, 05:58:53 PM
That's it!  That's all we get?  What happened?  Who else flew?  How did they fly?

Title: Re: Michael's Skywriter build thread
Post by: Michael on May 09, 2015, 06:31:55 PM
Out of respect for Jack, I'll wait for the tickler.
Title: Re: Michael's Skywriter build thread
Post by: Wingnutz on May 09, 2015, 08:11:38 PM
With God (actually Glenn, but he's pretty close) as my witness, "Yes...the test flight went well"...did require several clicks of down and didn't happen 'til 5:00 o'clock......sorry, at 2:00 I was still fabricating interplane struts!"
Don't know if my flight(s) will make the Tickler, but Mike Sierra Tango survived my attempts to make it defy gravity...twice...I am not yet a candidate for crash of the year 2015!
( I did wimp out before the maiden and stuck 1 oz of ballast in the cowling :-\ )
Title: Re: Michael's Skywriter build thread
Post by: sihinch on May 09, 2015, 08:23:12 PM
Congrats Bill! Sorry we missed you.
Title: Re: Michael's Skywriter build thread
Post by: Papa on May 09, 2015, 11:10:40 PM
Congratulations Bill.


Jack.
Title: Re: Michael's Skywriter build thread
Post by: Michael on May 13, 2015, 04:44:15 PM
Just adding a photo from Bobby.