pretty-airplane

I watch many days. It works pretty much good to fly!

cdodom

hey I think you can import that file into a simulator like the G4.5 and you can fly it....or thats what I heard

Alex Voicu

Elias,
There will be a wood version anyway. A friend of mine asked me if i can design a simplified wooden version and i accepted. The design is done and i'm waiting for the lasercut parts.

For the composite version i will need a little time, but it remains my primary target. The mold plug will be made of lasercut sections and depron blocks, all covered with fiberglass in the end. The work done by our french friends at [link=http://www.f3a.fr]www.f3a.fr[/link] is really inspiring (registration is needed to view the forums). There's a thread about one of the french designs here: http://www.rcuniverse.com/forum/m_72...tm.htm#7222837
I would love to mill the mold plug and i'm sure i can find solutions for all technical difficulties, but it's just too expensive for me. Will have to do it the old fashioned way

Alex Voicu

I doubt you can import CAD surfaces in any simulator. Game graphic engines usually work with polygonal surfaces and a complete rework of the model would be needed.

AmericanSpectre505

Elias,

That is just pure AWESOME LOOKING,.......I want one,...........................


Best Regards,

Bill Holsten

Advantage Hobby Fliton Field Rep/Custom Airframes of America/Dragon Fire Customs/Duralite/Guardian America.

highfly3D

Alex,

I went though the thread & it was simply amazing....... were helpful for some one who wants to build his own F3A fiberglass fuselage.

Alex Voicu

Here's the wood version i was talking about. It was designed as electric only, but with some effort it can probably be converted for glow power. Comparing to the composite fuselage, i had to simplify the shape as much as possible for easier construction. I had only 15 days to design the whole structure, so i didn't have time for a paintscheme or pretty pictures In order to keep the costs to a minimum, i had to split each side of the central fuselage box in 3 pieces and use smaller and a lot cheaper plywood sheets. The structure will be covered with 1.5mm balsa and the canopy and motor cover will be fiberglass construction.
I got the lasercut parts and i started building the prototype yesterday, so this time you'll see a few building pictures, not just Solidworks renders

Alex Voicu

The lasercut parts look good, maybe the 2mm plywood parts are a little burned around the edges but it should be ok. I started by assembling the sides of the fuselage central box, and while waiting for the epoxy to cure, i put together the basic structure for the canopy an cowling mold plugs and started working on the motor support.

Diogo21

Alex fantastic job.

just a little note, i think you need to make something to force the air getting out of the fuselage.
in the F3a Sebart models they just open an air exit on the down part of the fuselage and cover with orocover one of the vertical parts of fuselage, or in most of oxai models they put a 45 degrees balsa sheets just a little bit before the wing tube in the fuselage.

probably you already think what i just told, but i case you don't...

Alex Voicu

I thought about it but haven't decided exactly where to cut the opening for the air exit. It will be somewhere behind the wing, on the belly but i'll try to avoid cutting any of the balsa stringers. The 45 degrees balsa sheet is a good idea.
Thanks.

Jeff Boyd 2

Just curious . .

Is the former/framework for the cowl and canopy to be used for mold making ??

Cheers, JB

Alex Voicu

Yes, that's for the canopy and cowling mold plugs. I plan to fill the spaces with foam blocks, and the plywood frames will give me a good reference how much to sand when profiling the foam blocks. The foam is too soft so i'll add a layer or two of GF to harden the surface.

Kema

Landing gear area seems a bit too lightly constructed.

Alex Voicu

The landing gear support is hidden by the battery tray in the screenshots above, but is made of 6mm hard plywood. It is glued between 2mm plywood formers, with balsa reinforcements around the perimeter. Will add some carbon fiber to the area just to make sure.

DavidMC

My Feedback: (6)

Will the wood version be available as a kit. I would love to get one.

The way you designed it with the smaller plywood sheets, you could finally get a patter plane kit that doesn't cost an arm and a leg to ship (provided you get your foam cores cut locally).

Looks really nice!!

Cheers,
Dave

dhal22

just provide a laser cut file for us and we will all build one of these beauties.

Alex Voicu

Hi Dave,

Sure, if there's enough interest i can probably provide a short kit. But first i need to build the prototype and make all the necessary adjustments. As always with a new model, there are a large number of unknowns, and weight is one of them. Will have to wait and see the result.
Most plywood sheets are 610x310mm and the rest are even smaller, so size would be quite small indeed.

Alex Voicu

Small update: added carbon fiber to the mounting plates for the motor, gear, rudder servo and tailwheel. The firewall is made of 4mm liteply and 200g glassfiber on both sides, but i'm thinking about replacing it with something stronger. I added 1.5 mm balsa sheets to the sides of the fuselage box and put it together to make sure all parts fit perfectly. So far so good.

NJRCFLYER2

My Feedback: (42)

Very impressive work on this! One suggestion for weight savings is to construct the firewall from 1/4" cross grain balsa laminated with CF cloth. I use small dowels embedded in the balsa to create the mounting hardpoints. This is very strong and much lighter than a plywood, or CF laminated plywood firewall. The firewall I did for my Integral came out to 1.6 oz. You can do the same for the landing gear mounts. If you really want to save weight in the main landing gear mounts, I recommend studying how Wistmodel designed the Vivat, Prestige and Bravo. There's nothing else out there that I know of that is so light and durable as their system.

Alex Voicu

Thanks for the suggestions. The landing gear idea is very ingenious and i'll keep it in mind for the composite version. The wood structure was designed with a hard LG mounting plate and changing it would require a major redesign of the area.

For the firewall i need something that's 4mm or 1/6" thick, so i don't have to modify other parts. Do you think CF laminated 4mm cross grain balsa will work or is it too fragile? Since i'm going to lasercut another firewall, i can test a few ideas.

f3a05

I have used CF laminated end grain 4mm balsa as a firewall in the past for 160 2-stroke F3A motors-the only addition was to anchor the captive nuts, for the motor mount, in separate little doughnuts of liteply glued to the rear face, to avoid piercing the CF skin.
200 gram cloth, or even 90 gram, works fine.
Nowadays, I use two layers of 2mm liteply, bonded together with the outer grain of the two layers at 90 degrees to each other;
and faced with any choice of 200 gram glasscloth, 200 or 90 gram Carbon fibre cloth, whichever is available.
This firewall has worked for me, for electric, 2-stroke, 4-stroke, without problems.

MTK

4 mm end grained balsa laminated with carbon cloth on both sides is very strong. For electric, 3 mm end grain is fine. Vacuum bag it as Ed showed to achieve the best contact and highest carbon to epoxy ratio.

I also think this is nice work.

MattK

Alex Voicu

I was a little busy last week, but i finally found some time to work on the fuselage the last couple of evenings. The fuselage box is now finished and the hot air deflector installed.
I am still amazed how well all the parts assembled together without sanding anything and how stiff the structure is. I made a few small mistakes though, but it's nothing serious.
I cut 2 more firewalls and i'll use carbon cloth on both sides to make it stronger.

Doug Cronkhite

My Feedback: (34)

I'd love to build one of these when you get the final version done (or even beta version done). I'm one of those crazy people that actually enjoys building my airplanes still..

Magne

I think there is quite a lot of crazy people out there...

Alex, there is a lack of good basic built up models suitable for pattern/F3A in the 2m size. (Ok, there are some, but there is room for more.)
A "short kit" consisting of milled/laser cut plywood parts, composite canopy and cowling, and possibly plywood templates for wing cutting, would probably sell quite well, and be cheap to ship. I think it would be easier for you to sell a few of these, than full composite models.

Nice work.

Regards,
Magne