#27 Model Airplane Building Clinic >> Mimi DLG 1 meter polyhedral<<

[aeroknot]

Good to know, Frans. I sanded for about 5 minutes yesterday, that's the only free time I've had to build the past few days.

I started my throwing blade last week (9/13). It's a little thin and I may add two more layers. Filed in a water bucket as in Frans' web site photos.

I used 0.5mm x 10mm (edit correction 8mm wide) CF flat inside a cylindrical CF tube seems pretty durable. Currently weighs 1 g.

I tried to get the light to reflect over the embedded CF flat on the photo.

[aeroknot]

I made a second throwing blade, and added 0.5mm CF flat and thin non-directional CF to the first.

The second throwing blade has two pieces of 0.5 x 8 x 45 mm CF flat, both inside the 10mm diameter CF tube.

[aeroknot]

I'm completing my first wing. It'll be good practice.

[aeroknot]

improving from one to four. CA sometimes takes a while to harden, I found out.

[aeroknot]

I ordered some uni-directional CF and uni-directional (UD) kevlar, the kevlar to substitute for the rooving.

1" x 12 feet of each from ACP composites.

3.7 oz CF,
2.5 oz kevlar
hopefully not too thin,

2.5 oz. "Uni-Web" Unidirectional Kevlar®

3.7 oz. "Uni-Web" Unidirectional Carbon Fiber

[aeroknot]

I prepared the balsa with some thin spray polyurethane - I also have some spray clear acrylic - but used the spray polyurethane to prepare for fiberglassing the wingtips and wing panel joints.

[aeroknot]

test test measure measure test cut

used the skyshark p100

[aeroknot]

note that Frans on his web site shows a rectangular blank as the fuselage bottom, and shapes it after all the gluing, which is the preferred method, but I had already cut my fuselage bottom.

Be careful of epoxy leaking to the side of the front CF tube block when gluing the front block in - this will interfere with the fuse sides if not cleaned up.

[oswaldcroaker]

I'm enjoying your thread; thanks. One question: on the plan is shown "Template balsa 1x1mm, 1x5mm" and "Template ply 0.8". It looks like these are in reference to the wing tip piece; is that correct? It looks like you used two ply pieces instead of two balsa pieces; am I missing something here? I guess I'm not sure what "Template balsa" and "Template ply" are referring to. Any help would be appreciated. Thanks!

[Frans Bal]

The tip is a lamination of three pieces.
First 1 mm balsa
second 0.8 mm ply
third 5 mm balsa

The balsa pieces fit between the D-box and the trailing edge.
The ply piece is a bit bigger at the D-box side. The extra material fits in a slot cut in the D-box

[aeroknot]

Originally Posted by oswaldcroaker

I'm enjoying your thread; thanks. One question: on the plan is shown "Template balsa 1x1mm, 1x5mm" and "Template ply 0.8". It looks like these are in reference to the wing tip piece; is that correct? It looks like you used two ply pieces instead of two balsa pieces; am I missing something here? I guess I'm not sure what "Template balsa" and "Template ply" are referring to. Any help would be appreciated. Thanks!

Frans' web page (http://f3k.nl/) (also, email him for his plans) has very detailed and extensive step by step documentation of the Mimi build. Click on the "MiMi" link there - lots of photos organized by plane part. (There's also a link to his web page on post one.) He's posted a few of those photos here - very nice.

The wing tip I built according to his plans, with no unintentional deviations.
The only major building blunder so far was to glue the wing outer panels at the incorrect angle - therefore my current wing is a "practice" wing.

[oswaldcroaker]

Thanks. I emailed Frans and he was very helpful. He answered my questions and then directed me to his site, which, BTW, is great!

[aeroknot]

Glad to answer questions and to help! It's a great idea to review his photos before a major building step.

[aeroknot]

1 - sides - wait a little while - (using Titebond II)
2 - top - and wait 10 minutes
3 - front - wait until set
and then sand.

Not showing every detail of the build, such as forming the front block, etc - but most of those are on Frans' site. It's a good idea to check his photos.

[aeroknot]

I wasn't sure what to use on the trailing edge - I used a hardwood 3mm dowel (maybe cedar?), planed and sanded. I like the trim, though. Ply would have worked. Could probably still sand some more

[aeroknot]

and today's lunch.

shrimp, potatoes vegetables. I'll post the recipe if anyone is interested. Could substitute other for shrimp.

[aeroknot]

...a minor modification. I used 10mm wide balsa for the elevator support, glued then sanded from about 7mm at the CF tube to 10mm at the elevator side.

Other than that, I don't plan on any modifications.

When I'm finished buildings - and I can see it from here - I'll post a list of unplanned deviations from the plan - blunders, oops, gaffes etc.

Again, note that how I'm building (beginning balsa builder) and order of building may differ than what's better

[aeroknot]

the front block is the original 6mm balsa support that I did not use. I'm using it to make sure the elevator support is parallel to the CF tube fuselage.

I also tried to make sure it was level right to left.

The tape is to protect the portion that I do not want to sand. Learned from Fran's photos.

[aeroknot]

Balancing the wing left to right

I'm glad this is my practice build wing, because I've learned -
1. how to CA - with thin non-directional CF, lay the thin CF down and use a tiny needle to limit the amount of CA, use kicker or make sure the CA is hardened
2. in general, use tiny needles or nozzles for the CA, and store upside down.
3. I still have a 'heavy' hand with the epoxy.

[aeroknot]

I placed the front peg of the wing against the front former, marked where the hole should be, then hand drilled it starting with a thin drill bit and progressing to the proper size. So, the fuselage and front former are all glued before drilling the hole, so the hole ends up in the right place.

For the retaining screw further back, I measured the distance from the front former to the block in back, placed the wing peg in a hole with the wing upright - photo - then marked the previous distance.

Then, 3rd photo, I double checked the mark - looked about right - before drilling.

[aeroknot]

I used a drill bit one size smaller than the recommended drill bit size for the tap I'm using, since the tap is through wood and not metal.

I tapped the threads through the fuselage block and through the top of the CF tube but not through the bottom. My screw will of course not enter the CF tube, since that is where the control kevlar fishing line runs, but I wanted to get a good tap through the wood. Thought about squirting some CA in the hole to firm up the wood, but I don't want to make the taped hole threads brittle.

the retaining screw tap is specified on the plans as M3 - 3mm.

I have on hand a 4-40 English size tap, which is about 2.8 mm diameter and a selection of 4-40 nylon screws. I also have I think an 8-32 tap, whatever, which is 4mm and no corresponding screws.. so I used the 4-40 tap.

Photos - no tap photos, but maybe the tap hole is visible on the fuselage - the wing photo is pre-tap, I think.

[aeroknot]

First (first two photos), I checked the fuselage aft wing section fuselage sides height and angle - the bottom of the wing should line up and be parallel to the bottom of the horizontal stabilizer, otherwise, the fuselage sides need sanding. On first check, looks like it will be good. I'll recheck after the horizontal stabilizer is glued on.

[I beveled the vertical stabilizer so that the hinge line trough for the rudder will be on the right, for a right side control arm, for a right handed thrower. Maybe should be opposite for a left handed thrower? So looking from the top, the rudder hinge line will look like this l< . I'll post a photo of the hinge later, when hinged.]

I drew some guide lines, slid the vertical stabilizer - it was a tight fit but not too tight. So I used some non-stretching fishing line for the two wraps, then CA'ed it all at once.

I'll use the same fishing line for the control lines to the control horns from the servos. The fishing line is some type of kevlar dacron type material and does not stretch.

Next, I'll drill the hole for the tiny tube for the control line for the rudder, and install the tube and then on to the horizontal stabilizer.

Learning by doing.

[aeroknot]

Tape to protect the CF tube.

Used thin hard wall fuel line tube, probably outer diameter 3/32 inches, just over 1/16.

Used the power drill at about 30 revolutions per minute straight down using a 1/16 inch bit followed by a 3/32 inch bit.

Then drilled an angled hole - 1/16 inch bit followed by the 3/32 inch bit. I drilled the angled hole through the vertical stabilizer.

Then placed the thin hard wall fuel line tube into the hole, a tight fit so no need for CA. May need to tie it down. Tested with the kevlar fishing line I posted a photo of before and no binding.

[aeroknot]

Gluing the horizontal stabilizer on -
Used the magnets again to hold everything in place. Used Titebond II again.

The horizontal stabilizer was moved forward after the third photo.

Angles to make sure the horizontal stabilizer is perpendicular to the vertical stabilizer.

[aeroknot]

Was going to skip the kevlar strip on the horizontal stabilizer, but realized that the kevlar strip also protects the CF tube at the control line tube hole.