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Author Topic: The bluefoam model, or how to build a stunt plane without a bit of balsa?  (Read 30971 times)

Offline Istvan Travnik

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Dear Friends,
Succesfully I found a new place for my photos.
Please, visit my album here:

https://www.flickr.com/photos/171504164@N04/page1

Only bluefoam (Roofmate), some plywood, glass, carbon and epoxy. No balsa.
No lyrics, but questions are welcome.
Regards: Istvan (Europe, Hungary)  :!

« Last Edit: June 19, 2019, 03:32:56 PM by Istvan Travnik »

Offline MarcusCordeiro

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Offline Steve Helmick

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I looked at all the pictures, and found some very interesting details that could be easily adapted to more conventional models. I can't say I'm enamoured by blue foam construction, but somebody with balsa allergies might do well to consider it.  H^^ Steve
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Offline PatRobinson

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Hi  Istvan,
That is a clever and well done airplane and photo presentation.
Questions:
what are the specifications ? - wing area , wing span, tail area and span, fuselage length and etc.

component weights     - wing weight , fuselage weight, tail weight , hardware weight , total weight.
                                           How does weight compare to a built up wing or white foam balsa sheeted wing.
                                           How does your fuselage weight compare to a molded or standard balsa fuselage.
                                           How does your tail components weigh compared to built-up or solid balsa
                                           components.

Finishing Method   - It is unclear what method you used to finish this plane. Did you use epoxy finishing resin , with or without lightweight fiberglass as a substrate for your finish?  Blue foam can dent fairly easily so a hard substrate would seem to be useful.  What kind of primer and paint did you use?

My questions are to give us all a frame of reference to evaluate how your clever ideas might apply to other people's building plans.  

Finally, What were your reasons or objectives or rationale for adopting this method of construction?  

Once again, This is a great photo presentation. Well Done!!
                                                                                      Pat Robinson
« Last Edit: October 28, 2012, 02:03:38 PM by PatRobinson »

Offline sleepy gomez

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Istvan, I have been building with white one pound foam for forty years.  In the last few I have not used any balsa.  I developed and published the methods in 1974 when I was doing FF.  I have a table saw that lets me cut poplar to any size needed.  Being careful to balance size with strength I come close to balsa construction at a fraction of the price.  I use commonly available birch ply, .220" thickness for doublers, sometimes fuse sides, bell cranks and control horns.  I find the white foam to be of sufficient strength once it is encapsulated with spars and the normal silk span covering.  Silk span is applied with 50/50 white glue.  It is then sealed using a hot mix of unflavored gelatin. Once sealed any paint or dope can be used.  I do not sheet foam wings or foam stabs.   A note here is that with my income being Social Security I must build cheap.  An 800 + sq in area CL biplane only cost me less than $30.00 to completely build and finish.   No mine are not front row planes but they will fly with similar designs. 

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I hit the wrong key to post the plane with the above post.

Offline sleepy gomez

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I'll try this again.

Offline Douglas Ames

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<SNIP>
Finishing Method   - It is unclear what method you used to finish this plane. Did you use epoxy finishing resin , with or without lightweight fiberglass as a substrate for your finish?  

Finally, What were your reasons or objectives or raionale for adopting this method of construction?  

Once again, This is a great photo presentation. Well Done!!
                                                                                      Pat Robinson


My questions also... Outstanding work!

I can take a guess in regards to the second question- Probably tired of the 60 yr. old construction methods on this forum.  Z@@ZZZ
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Its very cool and my guess as to why is availability of balsa there.
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Offline Istvan Travnik

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Dear Friends,
I try to answer in logical order:
Why this method?
Very simple: in the early '80s my conventional balsa built-up models suffered from strong resonance. I tried to detune them from the engine's useful RPM interval, but no success. Finally the long pushrod broke, killing the plane & engine.
That time the white foam+balsa (or Obechi, etc.) planking method was known already, but in lack of vacuum-technology, and self-expanding, light polyurethane glues, I did not consider to be reliable and light enough. (And technically "elegant", as well :)
So I developed my method on extruded Polystyrene foam. As I observed under microscope, the blue has approx. half a big elementary bubbles, than the pink brand. All other parameters are similar. (Material, density, strength).
I find good finishing/laminating epoxy resin (nowadays is Huntsman (CIBA) LY 5052 type), and the steps are as follows:
1. Making the foam by usual methods: hot wire (not too hot, to avoid grooves), sanding by sand-canvas (120 or 150 grade), and/or trimming by balsa-plane, using razor-blade (!!).
2. Stabilize the surface by resin: I thin the epoxy resin by methanol, adding 20-30%, plus some talc, to better sanding ability. And "paint" the surface by this mixture. Do not worry: a GOOD resin will be hardened for tomorrow, anyway...
3. Sand the surface by sandpaper, grade 280. Even by wet method: the Polystyrene foam is NOT sensitive of water: how a big advantage over any wood!
4. Cover the surfaces by light glass (25-28 grams/sqm), or carbon tissue (9 grams/sqm), or light unidirectional carbon (where extreme strength is needed: in the central part of wing, horizontal stab.) The resin can be the same, as in point #2.
Inside parts (e.g. spar, etc.) must not impregnated by thinned epoxy.
5. Sand again, as written in #3. The surface is ready to paint. (I use to order nitro-based colors from auto-paint shop, covered by two-component acrylic hard lacquer.

Tomorrow I collect the measures and weights.
Regards: Istvan

Offline Paul Smith

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #10 on: October 31, 2012, 03:43:53 AM »
I tried the blue Styrofoam (genuine Dow from Midland Michigan) when I was building combat planes.

Genuine Dow is basically twice as heavy as generic white polystryene (which is often incorrectly called Styrofoam).
Dow is much stronger than white foam.
Some weight can be recovered with thinner sections.
Dow requires a lot more energy to cut.
Myh finished model went to 18 ounces vs 16 for white foam.

You have some very nice tools.
« Last Edit: November 22, 2012, 07:19:47 PM by Paul Smith »
Paul Smith

Offline phil c

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #11 on: November 01, 2012, 03:06:03 PM »
I tried this years ago, when Hobby Poxy was the only "good" epoxy available.  The main problem I had was that a layer of light glass and epoxy is as heavy as 1/16 in. balsa.  I had problems with dings on the surface.  any kind of thing that fell on it would shatter the finish.

I can get much the same effect using the white beadboard.  Hollowed out sections need a little thicker walls, but still are lighter.  Double covering with one of the light weight plastic films(including the SLC covering I have) weighs about the same as glass/epoxy and is very ding resistant.  One coat of autobody primer(spray can or spray gun), sand most of it off, leaving a very mottled surface.  Then go to whatever final finish you want.
phil Cartier

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #12 on: November 01, 2012, 05:24:59 PM »
Dear Friends,
The static basement of bluefoam is very simple: (excuse me for using metric measures):
a light, good balsa makes approx. 110 grams per liter, while the middle density (e.g. ROOFMATE SL-E type) bluefoam makes 34 grams per liter. It means that a 2 millimeter thick balsa equals 6 (six) millimeter thick foam. There is no doubt, the balsa construction needs ribs, while foam construction does not. As you remember, the stiffness of some shell structure is commensurable to it's thickness up to cube...
 Balsa's behaviour is similar to a sponge (since structurally it is some kind of "branch of tubes" since bluefoam is a mass of closed bubbles, no sponge. Paper or silk cover on balsa (well filled and prepared to paint) is not lighter than a light, glassfibre fabric with epoxy, but far less strong.

Offline Chuck_Smith

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #13 on: November 23, 2012, 09:48:02 AM »
I Like it! Very cool.
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Offline John KruziK

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #14 on: November 29, 2012, 04:12:07 PM »
Thats cool!!
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Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #15 on: January 01, 2013, 11:44:27 AM »
Wishing Happy New Year to every kind colleagues & visitors in 2013!
Istvan

Offline kenneth cook

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #16 on: January 03, 2013, 08:45:04 PM »
                      Truly amazing, fine work sir. Happy New year  Ken

Offline John Sunderland

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #17 on: January 12, 2013, 05:12:41 AM »
The Wart Hog was my favorite airplane from the cold war. I was a young American soldier that called in air strikes and artillery in the 1980'. My father built a version of a previous stunt design we did together. I was surprised he did that because he never really liked twin rudder designs when I was a child. He was however, checked out in the Air Coupe in the 1950's. If you have been a PAMPA member since 1999 you may have seen his twin rudder Chevelle. We published a single rudder designed based on Fancher/ Rabe numbers in Flying Models in 1998. Very nice work my friend. Your pictures and workmanship are superb!

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #18 on: October 21, 2014, 04:00:14 AM »
Dear Friends,
Some added info's abut usability and repairability of this technology. This August, in Poland, was organized a training competition, named "Kujawia Cup",  right before the World Championships. In the strong wind, by first corner of first inverted loop in the first flight, the model touched the ground: the complete split tail rolled after the slipping plane on the grass...
... and in the evening, right before midnight the model was reborn: some 5 minutes Epoxy to put together the foam parts plus glassfibered tape on the surface was enough, to fly again. So I did not lost the participation on the WCh's.
See photos from Claudia Kehnen's super album:
https://www.flickr.com/photos/fesselflug/14691155259/in/set-72157645923341020
https://www.flickr.com/photos/fesselflug/14875349204/in/set-72157645923341020

(Well, the WCh was organized so austerely, on rough grass for stunt)

Offline Avaiojet

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #19 on: October 21, 2014, 08:10:06 AM »
Istvan,

Nice, I like it. Outstanding modeling! We need more of this different kind of building.

There's this guy in Canada that builds that same way. Has been for years. He's on U-Tube. I've made graphics for him.

Only he builds large R/C models. I believe his TWA Constellation is 16' in span.

Keep up the good work.

Really nice model you have there!

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Offline Howard Rush

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #20 on: October 23, 2014, 05:34:15 PM »
It was my pleasure to meet Istvan and see his plane in August.  I showed pictures of it at the WC presentation at the Golden State contest last weekend.  It also has an Expocrank mechanism, viewable through the canopy.

I think Istvan looks like a lightweight version of Bill Rich, a concept I had difficulty communicating with Istvan.  Sorry, Istvan. 

The second picture below shows the broken fuselage, which was easily repaired. 
The Jive Combat Team
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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #21 on: October 23, 2014, 05:54:55 PM »
Dear Friends,
Visit my album:

https://plus.google.com/photos/117790355930193335731/albums/5715088163776972593

Only bluefoam (Roofmate), some plywood, glass, carbon and epoxy. No balsa.
No lyrics, but questions are welcome.
Regards: Istvan (Europe, Hungary)  :!

You do very nice work!
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Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #22 on: October 25, 2014, 06:26:04 PM »
Dear Howard,
Thank you very-very much for the photo of broken fuselage!
I would like to add some informations what we can see: the pushrod is carbon tube, bondaged at the end with some Kevlar string, fixed with Epoxy glue, and it has 5 mmm (1/5") thread in it, for the adjustability, with the broken part of the homemade pushrod fork. Its material is "ZX-100":the plastic, what  practically never wears out. I used this material for the bellcrank and the arm of the exponential mechanism, too.

Offline Howard Rush

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #23 on: October 25, 2014, 06:45:38 PM »
Here is the lowdown on ZX-100: http://www.zedex.de/ZX-100_Family.344.0.html?&L=2 .   
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Offline FLOYD CARTER

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #24 on: October 26, 2014, 04:58:07 PM »
I don't think anyone has mentioned the use of blue styrofoam for making molds for balsa skins.  Certainly easier to shape than pine, which I used to use!  I have styro molds for wing leading edge sheeting, fuselage balsa turtledecks, fuselage tops and bottoms.

Still use balsa for planes, though.  Wood is easy to repair (when necessary).

Floyd
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Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #25 on: October 26, 2014, 06:57:40 PM »
I remember, when I broke wooden airplanes, in most cases there were some elements or fragments to be replaced, since the broken surface was "bony", crushed, not plain.
A bluefoam structure is more "grateful": it is enough to put together the parts, and cover the line of braking by thin glass.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #26 on: January 01, 2015, 03:01:08 PM »
Dear Friends,
I wish you a Happy New year in 2015!
(and nice models, hundreds of perfect flights, best results...) H^^
Istvan

Offline frank mccune

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #27 on: January 02, 2015, 03:27:08 PM »
       Hello Istvan:

       Great work!

       What engine was in the airplane?

       How did you get your cat's eyes to glow so brightly? What food does the cat eat?

                                                                          Stay well,

                                                                          Frank McCune

Offline Howard Rush

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #28 on: January 03, 2015, 12:45:23 PM »
How did you get your cat's eyes to glow so brightly? What food does the cat eat?

Nitro.  Light's 'em right up.
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Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #29 on: January 07, 2015, 04:03:01 PM »
Dear Frank,
The engine is MOKI-M10 type, named in export terminology to MOKI-51.
Built still in 1987, and I have some 5-6 pieces. I used the first one from 2000 to 2009 (ten years, approx. 2000 flights).
Chromed steel sleeve, ringed plain piston, 3-channel Schnuerle scaveging, two-part housing.
And many-many modifications by me. (outlet 130° to 140°, bypass 115° to 110°, cooling fins off from cylinderhead, steel deflector in combustion chamber, and the conventional venturi + spraybar combo changed to HP-40 -type (one side nozzle and needle for self-cleaning).
Own designed tangential inlet silencer, soldered by Technoweld.
Weight, power and behaviour is very similar to the old ST-60, however a bit less vibration.

The photo with the cat was made with flashlight in a dark room, and he looked direct on me :)

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #30 on: December 31, 2015, 07:51:32 PM »
Dear Friends,
I wish you a Happy New year in 2016!
Some news happened with the model in 2015: I tried two types of very good quality Czech 3-blade props, designed for electric motors. The bigger, 12.3" dia, well undercambered type made for the stronger MVVS motor, and I had to run it between slow and maximum RPM, in two-stroke style.
The smaller one 11,5" dia. made for AXI motor, not undercambered, and I could run it in 4-2-4 style, comfortably.
Undoubtedly, I liked the bigger more, (maybe the engine did not...:):) )
Istvan

Offline Avaiojet

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #31 on: January 01, 2016, 06:35:31 PM »
Istvan,

I just noticed your number on the wing. 0077.

Interesting and a great number!

Charles
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Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #32 on: January 02, 2016, 03:38:47 PM »
Dear Charles,
You can call me "Agent 0077", similarly to Mr. James Bond, if you want to :)
However, I got this number absolute at random, from the Hungarian Association of Modellers, when FAI ordered to use standardized form of listing of models, country by country, in the early '90s.
I am glad with it, because in the old pre-christian mythology of Hungarians (take 1100 years, or more), the "7" figure bears specially lucky meaning...
Istvan


Offline Igor Burger

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #33 on: January 13, 2016, 11:22:03 PM »
Istvan, I hope you use those full carbon props, not those for electric ... those light could be danger if used on piston engine.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #34 on: January 14, 2016, 03:48:48 PM »
Dear Igor,
That bigger, light, undercambered prop was the best - for the model and me, but not for the engine...
Since my engine is a ringed piston type, not ABC, I did not presumed it to be dangerous.
Attila Morotz has seen it, many times, wished it and tried it - and gave it back immediately, since that prop generated 30% more electric energy consumption, and some 20 centigrades higher temperature for his ESC...

Offline Igor Burger

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #35 on: January 14, 2016, 08:27:26 PM »
I am not surprised, yes that prop needs more power than those others, they are in use with large MVVS 8 motors.

However, that hub is not prepared to withstand periodical compression/expansion of single piston IC engine, so it is not good choice, be carefull.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #36 on: January 16, 2016, 12:35:33 PM »
Dear Igor,
I think I shall ask Mr. Sandor Havran, to make me some copies of maple. I hope, the the shape, airfoil etc. is not copyrighted by nobody :)

Offline Igor Burger

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #37 on: January 16, 2016, 09:12:37 PM »
no, it is not copyrighted, but I am not sure if Sandor can make so thin blade, may be better solution will be full carbon version, it is heavier, but safer

or what about classic underchambered prop for IC engines? may you can find some props from guys converted to electric

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #38 on: January 21, 2016, 04:10:31 PM »
Good idea, Igor!
I will ask them, to bring that props to Hradec Králové, in this May...

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #39 on: November 07, 2016, 08:08:38 AM »
I sent some questions to Istvan regarding his use of carbon and fiberglass on this airplane.  He requested that I post my questions and his responses so that others can learn from his alternative material use and building methods.
---------------------------------------------------------------------------------------------------------------------------------------


Q: What weight of fiberglass cloth did you use for that?

A: The fibergalass is very light: around 23 grams / sqm that means approx. 2/3 ounces / sq yd.  It is essential that warp/weft is approx 2:1, so we can play with the strength, by proper positioning.

Q: Did you use the same variety of fiberglass on the flaps?

 A: Yes, the wing body & flaps got the same cloth on. Only the centerwing front wears some 9 grams/sqm carbon tissue to reinforce, under the glass, where we take the wing by hand, and the landing gear needs it. The "spar" is double unidirectional carbon, covered by japanese paper by the phase of laminating. (uni. carbon has almost no weft and very easy to destroy it with the brush. Afterwards I sand the paper off.)


Q:Did you use fiberglass over or under the carbon fiber on the stabilizer/elevator?

A: Stabilizer got unidirectional carbon, with the same technology: it is extremely stiff and strong: the model has fallen 2 or 3 times onto concrete surface, onto back, and got no damage. Elevator covered only by glass.


Q: What type of glue or resin did you use with the fiberglass?

A: I used professional brand of aerospace industry: Huntsman (CIBA) LY 5052 resin and its hardener. It is very thin itself and and for the outside surfaces I thinned it by 20-30% Methanol. It was essential for the easy work and weight. I know, most of the epoxies won't get hardened properly in such a thin coat, or thinned by methanol. (maybe it is an effect of water vapour from the air)    


Q: What types of glues and resins did you use throughout the entire build?

A: Glue for most tasks: simple 5-minute transparent epoxy. You can put together the sections of fuselage in hand.
Serious places: engine bed and section, bellcrank support, and fuselage pockets: 24 hours transparent epoxy and heatgun.



Q: What type of paint did you use on the plane?

A: I ordered the colors in Nitro from an autopaint shop, and for covering cote, some 2-component Acrylic lacquer.
Maybe I will return to Polyurethane -based paints, that is more durable, and resistant of Methanol.


« Last Edit: November 07, 2016, 09:48:21 AM by Brent Williams »
Laser-cut, "Ted Fancher Precision-Pro" Hard Point Handle Kits are available again.  PM for info.
https://stunthanger.com/smf/brent-williams'-fancher-handles-and-cl-parts/ted-fancher's-precision-pro-handle-kit-by-brent-williams-information/

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #40 on: January 01, 2017, 06:19:18 PM »
Dear Friends,
First of all I wish you Happy New Year in 2017!
With new models and best results, without cracking.

 :! I found a special sanding tool, which can be very-very useful, in this bluefoam-technology.
If we have no computerized hotwire cutting equipment, we need to use significantly low temperature hotwire, not to melt some grooves into the surface. A "cold" wire (I use standard .35mm dia FAI teamracing steel wires) needs significant longitudinal push and pull "sawing"  movement for the good quality surface. This leaves many "hairy" residue on the surface. To sand it off needs very-very skillful hand, to avoid possible damage of the surface.
But, if yo use not some sanding canvas, but the good old Sandplate, it will easily "harvest" all the hairs.
« Last Edit: August 06, 2020, 06:14:26 AM by Istvan Travnik »

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #41 on: January 01, 2017, 06:21:20 PM »
Here is some photo of original Swedish Sandplate: it is very thin, pliable steel plate, even for concave surfaces (e.g. at flaps)

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #42 on: January 01, 2017, 06:25:00 PM »
...and two more photos:
I am sure, this is available in the States still, maybe under other brandname and  different vendor.

Offline Target

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #43 on: January 02, 2017, 12:41:10 AM »
Sometimes I've used white foam (2 lb density) to remove the hot wire hairs. It works ok. I sand all edges of my white foam block with a small bevel first.
I love the work you are doing with the foam!
Happy New Year,
Chris
Regards,
Chris
AMA 5956

Offline Avaiojet

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #44 on: January 04, 2017, 09:07:56 PM »
Dear Charles,
You can call me "Agent 0077", similarly to Mr. James Bond, if you want to :)
However, I got this number absolute at random, from the Hungarian Association of Modellers, when FAI ordered to use standardized form of listing of models, country by country, in the early '90s.
I am glad with it, because in the old pre-christian mythology of Hungarians (take 1100 years, or more), the "7" figure bears specially lucky meaning...
Istvan

Istvan,

Nice to see you back in the Forum.

Blue foam. What is the weight for one cubic foot?

I'm thinking of using pink foam for a project but not sure of the weight. I can find out.

Happy New year to you also.

007.  ;) ;)

Charles
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #45 on: January 06, 2017, 05:26:18 PM »
Dear Charles,
The blue and the pink brand is chemically the same: extruded Polystyrene foam. Blue's brandname is Roofmate, Floormate, Styrofoam. Original producer is DOW Chemical, and it is licenced worldwide. (E. g. by us, Hungary, in Europe.)
Pink is from Corning Glass originally, and that is licenced woldwide,too. (e.g. In Austria, near us, and named Austrotherm.)
There are different density and different compression strength variations.
e.g., a middle, universal variant,  Roofmate SL-E has 34 grams per litre density. (It takes right 34ozs / cu.ft)
The pink brand is the same, however I found approx half a big elementary bubbles under microscope, by blue brand. It can come from technology, the expanding gas, etc. Maybe the blue one takes up a little bit less resin, when we build up the surface.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #46 on: December 31, 2017, 06:49:16 PM »
Dear Friends,
I wish you Happy New Year in 2018!
Somewhere I found some characteristic photos on this model, from previous years, see below.
Istvan.

Offline Avaiojet

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #47 on: December 31, 2017, 07:03:37 PM »
Dear Friends,
I wish you Happy New Year in 2018!
Somewhere I found some characteristic photos on this model, from previous years, see below.
Istvan.

Istvan!

Hey! Agent 0077.

Been a while.

You won't believe this. Just a while back I thought of you and your foam constructed models.

I designed this biplane pusher and gave great consideration to your foam technique.

I didn't have the courage to tackle it. Not just yet. Balsa and ply. Boring.

Bring the Forum up to date.

Any new models or Builds in the works?

Charles

007   
Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #48 on: December 31, 2017, 07:32:50 PM »
Dear Charles,
We are in 2018 now, in Europe. (it's round 03 a.m.)
You can find me under "Steve Grassfield" nickname at facebook. (I have bad feelings about that kind of media, but it was a must, so I did that).
2017 mostly spent with building works of a new grass circle for our club, and no serious model building works. However new mechanism and main lines of a new model are on paper. This year I shall meet and compete with your national trio in Landres, France, at WChs :)
I would like to encourage you and all comrades to start a nice friendship with blue/pink foam, with this "sculpture-like" technology; I think, when some Sandplate and good Epoxy got in hand, there won't be serious problem. 
All questions will be answered here, if raise any.
Happy new year, again!
Istvan

« Last Edit: November 10, 2018, 04:02:24 PM by Istvan Travnik »

Offline Istvan Travnik

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Re: The bluefoam model, or how to build a stunt plane without a bit of balsa?
« Reply #49 on: January 01, 2019, 01:05:43 PM »
Dear Friends & Visitors,
I wish you Happy New Year in 2019!
Istvan


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