Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => Building / Construction => Topic started by: GuyOReilly on September 10, 2023, 05:32:27 PM

Title: Elder 40 Scratch build
Post by: GuyOReilly on September 10, 2023, 05:32:27 PM
Thank you @Michael for lending me the Elder 40 plans.
I will protect them with plastic wrap and hopefully nothing will get glued to the plans.

I looked at your kit build https://temac.ca/smf/index.php?topic=3785.0

Very interesting and informative.

I have few questions and I am pondering a way forward on this « winter build » aka « retirement build ».

1- Power to use.  I have an E-Flight 25 available.  Would that be marginal power?
2- Wing ribs.  The kit uses 3/32.  I plan using 1/16. Would that be adequate?
3- Fuselage uses spruce longerons.  I have poplar that I can strip to 1/4 square.  Any concern other than weight difference?
4- The kit indicates using thin plywood veneer to secure the joints on the exposed portion of the fuselage.  This allows more gluing surface between sides fuselage cross pieces.  I was thinking lacing with « dental floss » or thin thread to assist with rigidity. Any concern?
5- For balance, I was wondering cutting a hole in the firewall so that the battery could be placed far forward to assist with balance.  Any concern there with solidity and integrity of the firewall?
6- Landing gear.  I will use the wire wheels (see other building thread) and will place it further back than the kit. Here is a link to the build : https://temac.ca/smf/index.php?topic=8714.msg57913#msg57913
7- Tail section will be re-shaped as I like the look of round fin/rudder, similar to DR1 and the stab will have an increased area by rounding the leading edge.

I will post pictures soon of the work completed so far.

Thank you for your ideas.
Guy
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on September 10, 2023, 06:15:34 PM
Work completed so far:
99- Made a round Fin/Rudder
99- Made a rounder stab and elevator.
01- Tail skid
02- Pilot
03- Gun and wire post.
Title: Re: Elder 40 Scratch build
Post by: Michael on September 10, 2023, 07:05:03 PM
Quote from: GuyOReilly on September 10, 2023, 05:32:27 PM

1- Power to use.  I have an E-Flight 25 available.  Would that be marginal power?
2- Wing ribs.  The kit uses 3/32.  I plan using 1/16. Would that be adequate?
3- Fuselage uses spruce longerons.  I have poplar that I can strip to 1/4 square.  Any concern other than weight difference?
4- The kit indicates using thin plywood veneer to secure the joints on the exposed portion of the fuselage.  This allows more gluing surface between sides fuselage cross pieces.  I was thinking lacing with « dental floss » or thin thread to assist with rigidity. Any concern?
5- For balance, I was wondering cutting a hole in the firewall so that the battery could be placed far forward to assist with balance.  Any concern there with solidity and integrity of the firewall?
6- Landing gear.  I will use the wire wheels (see other building thread) and will place it further back than the kit. Here is a link to the build : https://temac.ca/smf/index.php?topic=8714.msg57913#msg57913
7- Tail section will be re-shaped as I like the look of round fin/rudder, similar to DR1 and the stab will have an increased area by rounding the leading edge.


1. An E-Flite 25 (on 4 cells with 60 amp ESC) will probably be enough for the plane to fly, but aerobatics may be difficult. You will need more weight at the nose to make up for the lighter motor.
2. 1/16" ribs should be okay.
3. I don't know which wood is lighter or stronger, but more weight at the rear (anywhere behind the wing) will make it more difficult to balance. It must balance as per the plans.
4. The small plywood plates work well to keep everything glued together. I wouldn't omit them.
5. I think that's okay.
6. Moving the wheels back may make takeoffs and landings more difficult.
7. Rob also used a rounded fin/rudder. Ir works fine.

Nice and fast work so far!
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on September 10, 2023, 11:04:09 PM
Thank you @Michael for confirming some of my thoughts.
Building light will be key.
I researched the performance of the E-Flight 25 and found the following.
Key Features
    Equivalent to a 25-size glow engine for sport and scale airplanes weighing 3–5.5 lb (1.4–2.5 kg)
    Ideal for 15-size 3D airplanes up to 3.5 pounds (1.6 kilograms)
    Ideal for models requiring up to 600 watts of power

I will need to source the 1/16 ply for the fuselage construction.
The nose weight should be taken care of by the placement of the battery extending through the firewall.
Additionally, the wing structure will be redesigned and based on the Carl Goldberg Eagle 2, using a dowel for the rounded leading edge and no capstrips.
The covering (and so many other things) remains to be decided, but I was inclined to go with dope and fabric covering.  My concern is the potential for warping the wing when covering.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on November 28, 2023, 10:37:44 PM
Cutting ribs using the stack method proved less than successful.  :-X
A template was produced (3D printed by John Dutkowski) and in less than 5 minutes, 5 perfect ribs!!   ;D
The project continues, 25 or so more ribs to go....  ::)
I will need some more 3/32 balsa sheets...
Title: Re: Elder 40 Scratch build
Post by: msatin on November 28, 2023, 11:44:51 PM
I understand you have the template, but when cutting the ribs are you doing them one at a time "manually", or are using a bandsaw (or some other type of machine)?
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on November 29, 2023, 08:43:19 AM
Quote from: msatin on November 28, 2023, 11:44:51 PM
I understand you have the template, but when cutting the ribs are you doing them one at a time "manually", or are using a bandsaw (or some other type of machine)?

Good Morning Mark;
One by one, tracing with a trusty and new #11 blade.
I think that the scroll saw would vibrate too much and rip the balsa up.
The template needs to be held in place; I used 2 nails in small holes because a small clamp would not allow cutting all around.
Once all cut, a punch will be made from aluminium tubing (1/2 inch or so) to make room for servo wires.
The notches for spars will be added top and bottom with a small saw by stacking the ribs.
More to come.
Guy 
Title: Re: Elder 40 Scratch build
Post by: octagon on November 29, 2023, 10:36:55 AM
I did the same building my Elder Guy. A nice little trick is to glue a piece of sandpaper to the bottom of the rib you are using as the pattern. Stops it from slipping on the balsa shee.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on November 29, 2023, 02:02:42 PM
Quote from: octagon on November 29, 2023, 10:36:55 AM
I did the same building my Elder Guy. A nice little trick is to glue a piece of sandpaper to the bottom of the rib you are using as the pattern. Stops it from slipping on the balsa sheet.

Great idea!! And it works.
Just done 6 more ribs in 4 minutes!
Progress.... but back to work now...
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on November 29, 2023, 07:36:33 PM
Rib and half-rib blanks all cut, remains the holes for servo leads, L/E cut-out and slots for the top and bottom spars.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on December 02, 2023, 12:42:13 PM
Wing construction advances.
Made myself a jig to punch holes for the L/E dowel and for alignment.
Trial fit and a bit of sanding with Duragrit.
Quite pleased with the result.
Next cutting for the spars.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on December 04, 2023, 01:59:52 PM
Plan laid down and protected (Thank you @Michael )
Some trial fitting and trying to figure out the spars and trailing edge etc.
Also, I will have capstrips approximately 1/8 by 1/16 on all ribs and half-ribs.
Center section will be covered with 1/16 and fiberglass/epoxy for strength.
Need to source some 1/4 square spruce spars.

QUESTION: Should the capstrips be placed only after the wing is off the building board?

Guy
Title: Re: Elder 40 Scratch build
Post by: msatin on December 04, 2023, 09:57:04 PM
Great progress Guy!
Title: Re: Elder 40 Scratch build
Post by: Frank v B on December 05, 2023, 03:03:05 PM
Guy,

Just so the TEMAC building world will not think I ignored your request for help.... I called you with some clarifying questions and gave you my opinion.
This is important so that if it works, it is your victory. 
If it doesn't work it allows you to say again  "It is Frank's fault".  ;)

Happy building... and keep building.

Frank

Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on December 21, 2023, 04:13:20 PM
Back into the build.
Tackling the fuselage and trying to understand why the fuselage sides do not go to the firewall.   ???
The fuse sides stop at F2, then the bottom and top doublers as well as the landing gear support doubler are added and they go to F1.
This is a confusing plan and building sequence.
I am planning on changing the fuselage side to go all the way to F1, retaining the doublers as they add rigidity.
Another change I will be making is the design of the "U-SHAPED" formers and the use of tabs.
I will not be cutting tabs and slots in the fuselage sides; butt glued will be ample strong.    :-\

Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on December 28, 2023, 01:13:57 PM
Back into building the Elder 40.
I needed to confirm the right thrust angle.
There was an 1/8 inch gap from vertical at a distance at 3.5 inches.

Given a=.125 and b=3.5,
c = 3.50223
∠α = 2.045° = 2°2'43" = 0.035699 rad
∠β = 87.955° = 87°57'17" = 1.5351 rad

Long calculation:
c =   √a2 + b2
=   √.1252 + 3.52
=   √12.265625
=   3.50223
∠α =   arcsin(a)
c= arcsin(   .125   )
3.5022314315305
= arcsin(0.035691530512412)
= 0.035699 rad = 2.045° = 2°2'43"

So who said they were never going to use trigonometry?
Yes, I have time on my hand now...

Title: Re: Elder 40 Scratch build
Post by: Frank v B on December 29, 2023, 04:27:44 AM
Guy,

Why all the math?
If you put in "just enough" right trust you will be fine.  ;)
Also "some" is better than "none".

Frank  (who else?) 8)
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 06, 2024, 01:44:52 PM
Back from the Christmas and New Year's parties, now time to build.
Two identical (almost) fuselage sides, next add the cross members.
Trial fitting landing gear block attachment and battery compartment floor.
Need to source 4 regular size servos; mini servos would probably not be strong enough.
The rudder will be pull-pull, all the cables and clevises were purchased during my Montreal trip at https://amr-rc.com/
Title: Re: Elder 40 Scratch build
Post by: Frank v B on January 06, 2024, 03:14:36 PM
Guy,

Will dig up 4 servos for you.
Happy retirement.  8)

Frank

Update: found them.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 11, 2024, 02:37:52 PM
One coat of walnut stain.
Not as pretty as Mark's Minuette, but it will do. :-X
The tape was to prevent staining the area where the stab will be glued.  The stain seeped under...
There is no varnish yet, maybe in a couple of days.
The receiver, servos and ESC/motor tested, all working well.  ;D 
Now moving onto the wings.
Guy
Title: Re: Elder 40 Scratch build
Post by: Michael on January 11, 2024, 04:48:03 PM
Looks great!
Title: Re: Elder 40 Scratch build
Post by: msatin on January 11, 2024, 10:21:42 PM
Looking fantastic Guy!
Title: Re: Elder 40 Scratch build
Post by: Frank v B on January 12, 2024, 11:42:42 PM
re:staining: getting the right colour

When repairing a scratched wood floor we use the stain in the varnish product.  The reason: you can darken the wood with each successive coat until you are happy.
If you use stain only, you cannot darken it once you put on the first coat of varnish. 
The trick is to always approach it from the light side and darken it until it matches or you achieve the colour you like.  Once it is too dark you cannot lighten the colour.  Point of no return.

Before and after photos of a wood floor repair.  Dipped a folded paper towel into the stain/varnish product and wiped it once.  Colour too light.  The second wipe was the final product  Total repair time- 5 minutes.


F.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 13, 2024, 05:13:43 PM
Wing starting to take shape.
First step, clean the bench.   ;D
Second arrange the parts and try to figure out where they belong using the plan as a guide.  ;)
I determined that the ribs should be evenly spaced at 3 inches with half-ribs in between.
Third, disregard the plan.   ::)
Mark the spar for ribs and half-ribs locations.
Next gluing and keep everything as square as possible while drying.  :-X
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 15, 2024, 01:46:31 PM
Wings assembled and joined epoxy drying.
I decided against capstrips.
The trailing edge will be feathered into the ribs; just a bit more sanding.
I am quite pleased with the addition of the 1/2 ribs (similar to what Micheal did on his Elder).
Next, ailerons and servo set-up and a million other things.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 15, 2024, 03:35:12 PM
I just could not resist assembling it.
The cowling is from Eric Adam's Estate.  see: https://temac.ca/smf/index.php?topic=8888.0
This is not as per the plans, but then again...
The project is 1/2 way there, with 3/4 of the work remaining.  ;)
It will be ready for a Maiden Flight in the spring.



Title: Re: Elder 40 Scratch build
Post by: octagon on January 16, 2024, 02:10:34 PM
Looks fantastic Guy. Good work. Love the cowl
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 16, 2024, 05:25:49 PM
Rudder control will be pull/pull.
I understand that the control horns should be the same length to help ensure adequate geometry and functioning.
Any advice on how to rectify the variance would be appreciated.
The standard Futaba servo output arm is shown and the rudder horns are temporarily installed.
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 19, 2024, 01:14:15 PM
Decals ordered on January 10, 2024 arrived yesterday.
They look fantastic and are quite reasonably priced, see https://www.ebay.ca/itm/265067576215
Next more building.
Guy
Title: Re: Elder 40 Scratch build
Post by: electroflyer on January 20, 2024, 12:07:45 PM
  Beautiful work Guy!

  Hope you are going to join Rob, Michael, Dave, Simon and myself for our "Elder" flights when we take over the sky with.....Elders!

   Glenn
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 21, 2024, 03:54:55 PM
Almost finished.
Needs:
 - 3C battery
 - pull/pull cables to be installed
 - Elevator pushrod to be sourced
 - Ailerons to be fabricated.
Then Maiden flight.
It weighs 3 pounds 12 ounces (without the battery).
For the elevator I have a flexible cable type of pushrod.  I am afrain that this may be too flimsy to ensure positive elevator control.
The hobby shop near me (Advanced Hobbies on 7th Ave. and Woodbine) had no nyrods in stock.
Anybody can spare one of these?

Next on the agenda: sanding and shaping ailerons.
Title: Re: Elder 40 Scratch build
Post by: Frank v B on January 21, 2024, 09:05:29 PM
Guy,

..Du-Bro 48" red Lazer Rod on its way to you tomorrow via MarkUber. ;)

Frank
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on January 24, 2024, 04:08:26 PM
FINISHED!!!   ;D
Ready for Maiden Flight as soon as the ground is green.
I am quite happy with the result.
The Canadian decals were ordered from the US, others were on hand. 
The rigging is not functional but adds a lot to the model.
Weight with battery 4 lbs 14 oz.
Should be able to perform some basic manoeuvres with the E-Flite 25 on 3 cells.
Title: Re: Elder 40 Scratch build
Post by: Michael on January 24, 2024, 09:51:35 PM
Looks great!

What is that now? ... 6 electric Elders in the club?
Title: Re: Elder 40 Scratch build
Post by: GuyOReilly on February 03, 2024, 12:51:03 PM
Too nice a day not to go for a Maiden Flight.
Winds 300 @ 3 knots.
A few up trim, left wing heavier (needs to be corrected).
Flew 10 circuits at 50%-75% power.
Rock solid; expo to be added to smooth things out.
Extremely happy with the flight characteristics and performance of the E-flite power 25.
Title: Re: Elder 40 Scratch build
Post by: msatin on February 04, 2024, 09:33:35 PM
Looks Fantastic Guy!
Congrats on the maiden