Mini Supra's build(bagged). [Archive]

ViktorF

Mar 03, 2009, 09:23 AM

For a long time I wanted to upgrade my Aegea. Now I'm ready.
I will document here two mini Supra's (2m Supra) build.
It will be basically building of the wings and tails because I already have the fuses and booms.
First I ordered two sets of the wing and tail cores from Anker.
These CNC cut cores are almost perfect. I had find only a few minor distortions.
Let say the best I ever saw.

I'll use Aegea spar system and wing/tail layup with some mods. Top surfaces be painted too.

ViktorF

Mar 03, 2009, 09:48 AM

First I has drawn the tails from data points(lots of work), then did full size templates.
Next the tails was cut to sizes and sanded.

soholingo

Mar 03, 2009, 12:07 PM

Once done I would be interested in you telling us which flies better the Supra or the Agea.

Thanks Viktor, always fun to watch your build thread.

Jay

ViktorF

Mar 04, 2009, 03:49 AM

May be Mr.Drela can tell us what a difference we can expect.

Stab balsa insert.

Berrie

Mar 04, 2009, 06:56 AM

Once done I would be interested in you telling us which flies better the Supra or the Agea.

I'm also interested. I would like to replace, some day, my Carl Coldberg Electra, for something more sophisticated. I had an electrified Aegea in mind. But if a mini-Supra is a better choice, I might consider to build me one to.

Thanks Viktor, always fun to watch your build thread.

Maybe I missed it, but how does the wingplatform from the miniSupra look like?
-Foils from the original Supra?
-al dimensions / 1.7?
-same dihedral and washout?

ViktorF

Mar 04, 2009, 07:25 AM

Here you go.

Berrie

Mar 04, 2009, 07:28 AM

That is CHARMING plane :D !!

Thanks, Viktor.

ViktorF

Mar 05, 2009, 04:03 AM

Tails ready for bagging.
1oz kevlar + 1.4oz glass for LE's.
1.4oz glass for facing.
All fabric is bias.

ViktorF

Mar 06, 2009, 02:52 AM

Kevlar cutting.
I saved enough 1.0oz kevlar scrap making DLG wings.
Four pieces for every surface. Sheared ahead and bias at rear part.
No spars indeed.

ViktorF

Mar 06, 2009, 08:54 AM

Mylars painted. May be I'll bag first tail set tomorrow.

ViktorF

Mar 06, 2009, 09:04 AM

BTW here is Sprite - 2m Supra in Vladimir's production.
Slightly enlarged wing area and kinda heavy in my opinion.
I'll beat that weight.

Specifications:
Wingspan: 2000 mm (78.7 in)
Wing area: 36.5 dm2 (3.92 ft2)
Wing airfoil: AG40, AG41, AG42, AG43.
Horiz. stabilizer airfoil: NT12-NT14
Weight (without ballast):
Sprite Thermal Glass 890 g (31.4 oz)
Ballast: 150...500 g (12...30 oz)
Control: Ailerons, flaps, rudder, movable horiz. stabilizer

PizzaHunter

Mar 06, 2009, 09:10 AM

What paint to you use? Looks like spray.

ViktorF

Mar 06, 2009, 09:17 AM

Two-comp auto paint.

Anker

Mar 06, 2009, 09:48 AM

Mylars painted. May be I'll bag first tail set tomorrow.

Viktor,

Please post weights of everything after bagging and trimming. I am very interested in comparing my weights to yours'. :)

Anker

ViktorF

Mar 06, 2009, 10:03 AM

Anker,

You'll be beat too :)

fnnwizard

Mar 06, 2009, 10:12 AM

This is definately a big help for I have this project on the to do list. Thanks much for sharing!

T.D.

Mar 06, 2009, 02:24 PM

Anker

Mar 06, 2009, 03:57 PM

"I'll beat that weight." Easily.

The mini-Supra-ish two metre I built in Spring of 2008 is flying at 646 grams (22.8oz.) with carbon capped spar and four servo wing and Drela style tail.

When I get back to projects next month I'm going to install a V-tail..perhaps bringing the weight down a bit more.

T.D.

I agree,

An integral spar system and a lightweight skin is easily the best weight to strength method available. Stressed skin is heavier, but much simpler and faster. I haven't finished my ship, but expect it to be around 25 oz when done.

Anker

ViktorF

Mar 09, 2009, 04:14 AM

billwolfe

Mar 09, 2009, 05:05 AM

Victor,

From the pictures we can see that your craftsmanship is superb!

Can you tell me, is there any noticeable bump from the glass facings at the rudder hinge line, or from the overlap of the two kevlar pieces on the horizontal stab?

Also, what method do you use to cut your kevlar fabric so straight?

I am looking forward to pictures of your wing.

--Bill

ViktorF

Mar 09, 2009, 06:06 AM

Bill,

It's there more or less. An problem of all bagged things.

Waxed paper and 3M77 as usual.

Don't be hurry, I do two projects same time.

ViktorF

Mar 09, 2009, 07:59 AM

Next tail bagged.

Anker

Mar 09, 2009, 02:23 PM

First tail done.
It's a little on the heavy side. 29gr.(1.02oz).
Anyway easier than yours 1.5oz, Anker? :)
I measured 4gr. of the paint there(difference between painted/unpainted mylars).

Next one should be lighter.

My next set will come out lighter. I painted both the top and bottom Mylars by mistake! Still won't come down to 1.02 oz. Very nice! :)

Anker

Anker

Mar 09, 2009, 05:06 PM

First tail done.
It's a little on the heavy side. 29gr.(1.02oz).
Anyway easier than yours 1.5oz, Anker? :)
I measured 4gr. of the paint there(difference between painted/unpainted mylars).

Next one should be lighter.

A slightly more elaborated response.

An experienced builder like Viktor building for himself should come out quite a bit lighter than me for the following reasons:

A) My paint needs to cover completely, otherwise I have to give the customer a discount. So my paint coat is a bit heavier than yours.
B) The weave better not show through, so I have to make darn sure the layup is wet enough. I also have a layer of very light glass acting as a cosmetic layer. This is the outermost layer in the layup.
C) I use a strip of carbon cloth at the leading edge to give stiffness to the stab. Using carbon rods is lighter, but it takes more time.
D) I use 1.7 oz Kevlar instead of highly sheared 1 oz Kevlar. The weight penalty is small

If I hadn't made the mistake of painting both top and bottom the difference would have been less.

Anker

PizzaHunter

Mar 09, 2009, 05:43 PM

Bagged wings have unhidden hinge lines everywhere? I mean, ailerons and flaps... and rudder.
http://static.rcgroups.com/forums/attachments/4/8/1/8/7/a2388749-113-IMGP2923.jpg

ViktorF

Mar 10, 2009, 04:26 AM

Yup. You cannot live with that?

Well, I beat myself too.
This time less paint, less fabric overlaps and less epoxy.
24gr.(0.85oz).

That glamoure color looks so darkish, may be I should add some white pattern over the wing for this one?

PizzaHunter

Mar 10, 2009, 10:35 AM

so molded wing is aerodynamically better?

Charged

Mar 10, 2009, 11:06 AM

PizzaHunter so molded wing is aerodynamically better?

No that much .

ViktorF

Mar 10, 2009, 11:07 AM

Theoretically yes.
In real life you hardly can feel any difference.

Anker

Mar 10, 2009, 11:27 AM

so molded wing is aerodynamically better?

Not necessarily.

A foam core wing is extremely good at holding its airfoil shape.

As a molded wing bends or twists there's nothing that prevents the skin from distorting at the points where its completely unsupported. A poorly built molded wing may distort very badly under high flight loads.

Anker

ViktorF

Mar 11, 2009, 04:58 AM

V-mounts making. So far ugly pics only.

I'll move this thread slowly untill the Genie wing be done.

ViktorF

Mar 11, 2009, 08:53 AM

A few hours later...

Berrie

Mar 11, 2009, 08:59 AM

A few hours later... + some carbon in your fingertips... ;)

They look very nice!

ViktorF

Mar 11, 2009, 10:50 AM

Not only :)

Anker

Mar 11, 2009, 12:37 PM

I am very intrigued by the molds you have for the V mount. Did you have them machined yourself? If you did, do you have the CAD files?

Anker

ViktorF

Mar 11, 2009, 01:47 PM

Anker,

Nope, that's hand machining. Thanks to my friends, they do that work for me time to time.Do you want one?(I mean mold :))

Anker

Mar 11, 2009, 03:42 PM

Anker,

Nope, that's hand machining. Thanks to my friends, they do that work for me time to time.Do you want one?(I mean mold :))

I'd love a V mount mold. Tell me what I have to do to get one!

Thanks/Anker

BMtech

Mar 13, 2009, 06:23 AM

Hi ViktorF,

In post 31, the last photo with the wood,do you use a piece of tube & rap the carbon around it or is there a mandrel that forms the tube?

Excellent work by the way.

Rick

ViktorF

Mar 13, 2009, 07:01 AM

Hi Rick,
That's clear?

jihlein

Mar 13, 2009, 08:44 AM

Are there 3 views or coordinates available for the 2 meter Supra fuselage pod? Does it use the Allegro boom?

John Ihlein
Albuquerque, NM

ViktorF

Mar 13, 2009, 09:43 AM

John,
I believe no. Ask Mark Drela or Vladimir Gavrilko if you want.
Or may be Anker have it?
You can use anyone 2M pod and boom though. I do that.

Wing-span

Mar 13, 2009, 11:00 AM

Are there many after market Boom and Pod fuselages available, apart from the Ava?

ViktorF

Mar 13, 2009, 11:05 AM

WS,

It's a question for me?
Personally I can get any boom size from manufacturer.

Anker

Mar 13, 2009, 11:45 AM

Are there 3 views or coordinates available for the 2 meter Supra fuselage pod? Does it use the Allegro boom?

John Ihlein
Albuquerque, NM

Here is a 3 view.

You can get pods from Mike Lachowski. Troy Lawicki has both pods and booms.

Anker

BMtech

Mar 13, 2009, 05:50 PM

V-F

That's what I needed ,a pic is worth a thousand words

R

ViktorF

Mar 16, 2009, 05:18 AM

Alternative joiners boxes try.
They turned heavyer than usual end grain balsa and it was not easier for making.

ViktorF

Mar 20, 2009, 07:02 AM

Some pics of midpanels spars making. Of course weight down when epoxy cure.

will_newton

Mar 20, 2009, 09:47 AM

Viktor, this is a really nice thread! Thanks for showing us all your work.

What weight unicarbon are you using to make the spar caps and kevlar tube for the joiner box?

ViktorF

Mar 20, 2009, 11:15 AM

Welcome to a board.
For the tubes 1.7oz kevlar+light glass. 3 wraps.
As about UD - I dont know. It's 0.1mm thick Russian UD carbon. May be around 80gr/sq.m.
It work well in my Supra spar.

cn0rris

Mar 20, 2009, 04:24 PM

Victor, you are an incredibly prolific builder. For those of you who aren't aware, Victor is simultaneously building a Genie, documenting it in a build log (http://www.rcgroups.com/forums/showthread.php?t=1000012) here on RCGroups as well.

ViktorF

Mar 23, 2009, 05:09 AM

More spars pics.

soholingo

Mar 23, 2009, 11:58 AM

Viktor,

How do you find the time to build so much? I would love to be able to put this much time in the workshop.

J

Anker

Mar 23, 2009, 12:35 PM

Viktor,

How do you find the time to build so much? I would love to be able to put this much time in the workshop.

J

My "solution" was to get laid off and not be able to find another job. Now I build all day, but for other people. But I really enjoy getting better and better at it.

Anker

PizzaHunter

Mar 23, 2009, 02:23 PM

Anker, one philosopher said, that it doesn't matter what's your job, only the way, how you perform it, really matters!

Viktor, could you show us some photos of spar caps construction? If you have such photos.... I think it would be interresting for everyone here.

ViktorF

Mar 24, 2009, 04:13 AM

Jay,
I don't know. :)

PH,
It's quite simple. All you need is glass surface, polythene film, peel ply and vac equipment.
You can see a UD strip for tip caps at the pic #1 and bagged sample at the pic #2 .

ViktorF

Mar 24, 2009, 04:51 AM

Kevlar and glass wrap.
First midpanel spar are bagged.

ViktorF

Mar 25, 2009, 10:47 AM

First mid spar done and one set of the tip spars bagged.

ViktorF

Mar 27, 2009, 06:25 AM

Finally both spars finished. One 69(70?)gr., other 79gr.
Heavier contains thicker midpanel caps for TD capable.
Lighter one for electric version.
Really doing the spars this way is more difficult than tube spars in commercials wings.

Drela's Aegea II spar weight 116gr. Not sure about the weight of the main bolt plate - it's included or not.

Anyway my much lighter. Most reason - foam webs instead of end grain balsa and a bit undersized spar caps.
For the joiners I use 6mm carbon rods(10gr) instead of 8mm carbon tubes(15gr).

Knowing that the original spar has double safety factor, some weight reduction should not be a problem.

Wing-span

Mar 27, 2009, 07:34 AM

This is a lesson for us all. Well done.

VHO

Mar 28, 2009, 03:13 AM

Hello again Viktor,

Very good work as always. Do my eyes deceive me or have you omitted the dihedral in the center panel?

If so, why?

Hutton

ViktorF

Mar 28, 2009, 05:55 PM

Ha :) Your eyes don't deceive you.
0 degree midpanel, 7 degree each tip. I just want to try that.

T.D.

Mar 28, 2009, 08:16 PM

I used a flat centre panel on my Supra-ish two metre with 6.5 degrees on the tips (EDA = 5.2) and it is rock solid stable in the turns...it turns quite well on rudder and elevator only as well so when cored in a thermal I rarely ever touch the ailerons.

T.D.

Anker

Mar 28, 2009, 09:22 PM

Ha :) Your eyes don't deceive you.
0 degree midpanel, 7 degree each tip. I just want to try that.

Flat center and 7 degree tips is how I build both 2M and 134" Supras. Perfect combination.

Anker

StevenatorLTFO

Mar 28, 2009, 09:53 PM

My "solution" was to get laid off and not be able to find another job. Now I build all day, but for other people. But I really enjoy getting better and better at it.

Anker

Anker,

Well, from the looks of the wing I just got, you've gotten very good at it. I am most pleased!!!

Steve

Anker

Mar 28, 2009, 09:57 PM

Anker,

Well, from the looks of the wing I just got, you've gotten very good at it. I am most pleased!!!

Steve

Steve,

I can't yell you how pleased I am that you are happy with the wing. Many happy flights with it!

Anker

ViktorF

Mar 30, 2009, 02:49 AM

Time for the cores.

ViktorF

Mar 30, 2009, 03:04 AM

Cutting the spar slot and wire channel making.

ViktorF

Mar 31, 2009, 10:15 AM

Next...

ViktorF

Mar 31, 2009, 03:06 PM

Anker

Mar 31, 2009, 05:23 PM

Some remarks.
I have hurried with the cores joining. Because of it I had some problem with removing foam from wire channel. Unwanted hole covered with the glass.
Also I have found that the midpanel are to much sweeped back. So I cut the rear cores apart to avoid wing platform distortion. The last picture shown that. The gap will be filled later with foam wedge.
Not disaster at all.
Just too much builds...

Viktor,

The cores are cut a tiny amount too large because CNC foam cutting creates exactly the problem you ran into. Because of the heat the trailing edges will shrink or melt back a bit. If you want the plan form exactly right you need to sand the ends of the cores a tiny bit to get them back into shape. If you had built dihedral into the centers you would have done that automatically.

Thanks for reminding me of that. I am about to write a document that I will throw in with cores that I ship.

Anker

target

Mar 31, 2009, 05:26 PM

Hi, Viktor.

Are the servos mounting ahead of the spar or behind it, with or without RDS?

Also, what fixture are you using to cut out the taped over triangle at the surfaces hinge line on the wings?

Does anyone produce for sale that pivoting stab mount for a reasonable fee?
I like to bag wings and tails but so far have only done slopers. It might be time for a 2M warmup before a 3m for me.....

Thanks. Looks great!

Target

ViktorF

Apr 01, 2009, 02:41 AM

Anker,

I know about TE shrinking and just has missed the alignment checking because of a plenty of work.

Target,

One plane are for me and it'll with RDS. Of course servos behind the spar.
Second plane is for sale and so far no decision about that.

Sorry I haven't understood your next question. What do you mean?

ViktorF

Apr 01, 2009, 02:46 AM

Top spar epoxy/microballons filled.

will_newton

Apr 01, 2009, 11:03 AM

Does anyone produce for sale that pivoting stab mount for a reasonable fee?
TargetI would contact Bud Elder. He makes stab mounts for the Supra 3M and Allegro 2M. If you do a search here or on the Yahoo Allegro Lite group, you can find his e-mail address.

target

Apr 01, 2009, 11:43 AM

Target,

Sorry I haven't understood your next question. What do you mean?

Hi, Viktor-

I wonder if you know of anyone that sells the carbon stab mount that you made? Maybe Anker if he gets a mold? I would like to think of building one of these planes, but that one part seems painfull to produce one time. I would rather buy one than make one...

Thanks,
Target

target

Apr 01, 2009, 11:45 AM

I would contact Bud Elder. He makes stab mounts for the Supra 3M and Allegro 2M. If you do a search here or on the Yahoo Allegro Lite group, you can find his e-mail address.

Thanks, Will!

Target

ViktorF

Apr 02, 2009, 02:31 AM

Target,
Anker still not have the mould for V-mount(at least from me).
And I haven't understood this question:
Also, what fixture are you using to cut out the taped over triangle at the surfaces hinge line on the wings?

ViktorF

Apr 02, 2009, 03:45 AM

Top sanded and bottom filled.

target

Apr 02, 2009, 02:32 PM

Target,
Anker still not have the mould for V-mount(at least from me).
And I haven't understood this question:

Viktor-

Hello.
I will find out shortly by keeping my eyes on your build thread.

Please post pictures of cutting off the flaps and ailerons from the wing cores, and also facing the flaps and ailerons with fiberglass for me, that is what I am unsure about.

Thank you. :)

Target

aitor_ol

Apr 02, 2009, 05:45 PM

Hi Viktor,

first of all, great manufacturing !!

my question, how do you sand the epoxy/microballon once cured ?? isn`t it very hard compared with surrounding foam.

regard,

aitor

ViktorF

Apr 03, 2009, 03:13 AM

Target,
I'll show what you asked after approx one week. Be patient please.

Aitor,
Really not so easy and I hate this step a bit. Masking tape for protection, sanding bar, pair of the hands and a pair of the eyes.
Foam dents, if any, under masking tape can be corrected with the hot water when all sanding done.

aitor_ol

Apr 03, 2009, 04:51 AM

Although i´m not an experimented builder,

could the epoxi / microballon be vacum bagged under a mylar strip slightly wider than the spar ?

Regards and congratulations once more.

ViktorF

Apr 03, 2009, 05:01 AM

Thanks.
I wouldn't like to try it for the several reasons. :)

aitor_ol

Apr 03, 2009, 05:04 AM

what are those reasons ?

Anker

Apr 03, 2009, 07:35 AM

Hi Viktor,

first of all, great manufacturing !!

my question, how do you sand the epoxy/microballon once cured ?? isn`t it very hard compared with surrounding foam.

regard,

aitor

I found, by accident, that epoxy penetrates light spackle to some extent and creates a much stronger compound than pure spackle. This suggest that it is possible to intentionally make the thickened epoxy layer slightly lower than the top of the foam (I am talking 100's of an inch), and then use spackle to bring it up to the foam level and sand it completely smooth. Then, just before placing the core between the mylars, roll a thin layer of epoxy on the spackle.

Anker

ViktorF

Apr 03, 2009, 10:03 AM

what are those reasons ?
That will cause to much messy.

Filling and sansing midpanel spar done.
Now to tips. I'm sorry, some pics are missed.

PizzaHunter

Apr 04, 2009, 04:01 AM

Does your Supra wing have any washout twist?

Charged

Apr 04, 2009, 06:33 AM

The spar in the tip panel is quite unneccessary . I would have gone without a spar in the last tip panel .Could save some weight from it .

ViktorF

Apr 04, 2009, 08:02 AM

PH,
Yes. Washout are inbuilt in bigger tip panel if Anker didn't ignore that :)

Charged ,
Weight saving almost nothing.
I feel myself better whit the full span spar at tip landings(happen sometime).

ViktorF

Apr 04, 2009, 08:12 AM

Top sanded and bottom filled. Was used flat and airfoiled sanding "tools".

Now I'm gonna fly. Finally.

ViktorF

Apr 06, 2009, 12:13 PM

Sanding, trimming and cleaning of the first wing is done.
At this stage the wing weight is 235gr. Hope for 400gr finished.

ViktorF

Apr 06, 2009, 12:18 PM

With the next one I'll do capping after bonding the spar to the cores.
Each time something different.

PizzaHunter

Apr 06, 2009, 03:51 PM

Are you going to use the same fuse as your Aegea has, or miniSupra will have it's own?

ViktorF

Apr 07, 2009, 02:39 AM

No reasons for doing a new fuse for two planes or so. And no time too.

ViktorF

Apr 08, 2009, 09:03 AM

Wire channel. More comfortable making without balsa caps.

Anker

Apr 08, 2009, 09:33 AM

Wire channel. More comfortable making without balsa caps.

I love your cutting jig, Viktor. When cutting the cores, I can also cut the channels, but the access slot will be from the bottom.

Anker

ViktorF

Apr 08, 2009, 09:42 AM

Why you can't cut wire channel through spar channel?

Anker

Apr 08, 2009, 11:46 AM

Why you can't cut wire channel through spar channel?

I can if I cut the spar out on the CNC cutter. I have to add that to my cutting program, but its pretty simple.

When I wrote the reply I was thinking of not cutting the spar out and just cutting the wiring channel. Its better to do both the spar and wiring channel.

Its actually quite interesting how its done, so I'll do a quick description.

The foam block is held down by a vacuum chuck so its both held flat and so it can't move. The cutter starts with the top of the airfoil and cuts all the way to the leading edge and out of the foam with a lead-in. The program pauses here and prompts you to remove the top core. The wire then comes back over the top and makes the two vertical spar cuts down through where the bottom of the airfoil will be cut out. When cutting out the back of the spar it will make a detour and cut the wiring channel. After making the vertical spar cuts, plus the wiring channel detour, the wire moves back to the leading edge and proceeds to cut out the bottom of the airfoil. The point is to always have the foam being cut held firmly by the vacuum chuck so the cut becomes accurate.

Anker

ViktorF

Apr 08, 2009, 02:13 PM

Anker,

I meant that you can(or why you can't?) do cutting the wire channel when the hot wire are in your tube spar channel.
Cut as usual. When 3/4 diameter of the tube spar channel is done just run hotwire for making wire channel, then go back(really forward) to finish the rest 1/4 of the spar channel and further the rest of the bottom airfoil up to TE as usual you do.
This way you'll have both channels interconnected. As you use the rods to prevent filling the wire channel with epoxy that shouldn't be problem. Just wax the rods well.

Anker

Apr 08, 2009, 06:07 PM