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        Discussion 48'' GRX-V1 3D Foamie(FREE PLANS)In multiple sizes and formats

#1 Get Real Apr 29, 2009 07:02 PM

48'' GRX-V1 3D Foamie(FREE PLANS)In multiple sizes and formats
22 Attachment(s)
Cant beat owens pink for big foamys,$8.00 for a 8x4 sheet. Cut this out over the weekend and put gear in it yesterday. Got two flights in today with it,doesnt need much.. probally a little expo adjustment and minor cg adjustment.

Specs: (Original Version)
48'' wingspan 51'' long
Auw 30-34 oz(could get it down to 30 oz or less on 3s set ups)
4 hs 65mg's or hs-81s or hs-85s
350-400 Watt outrunners
40-50amp esc's
Apc 12x6-13x6.5
Zippy flightmax,Turnigy etc 3s 2200 $10.00 packs

Owens pink and gorilla glue for the build.

Suggested hardware:Robart hinges.. packing tape will get you by,Still working on the rest but many will have stuff laying around or do z-bends for linkages and use standard control horns with a ply backing glued into the foam.. lots of options... i used hardware from a plane i took out of service. At some point it will have landing gear but that will increase weight and drag,for now its a belly lander in grass if your starting out(i dont suggest hand catching to anyone.. the prop can shred you).

Suggested Gear: MOTOR:350-400 watt outrunner (350 watts is plenty but some like more Power!),reaper gr-35,torque 2814-820,torque 2818-900 will all work well. LIPO: 3 to 4s 2200 lipo(cant beat $15.00-$25.00 zippys)use what ya got though,apc 12x6 to 13x6.5 prop,still want to try a xoar on this one(they sound sweet and pull good). SERVOS: Hs 65mg's work.. hs 85s would really rock(will try 3 dollar9g hxt hobbyking servos eventually). ESC: 45-60 amp esc's are plenty.

Throws And Expo:Throws in video(more than needed),elevator 60 degrees,rudder 60 degrees,ailerons 50 degrees,high rate starting point for 3d(i'll fly this soon).. 50 degrees on elevator,45 degrees on rudder and 40 degrees on ailerons.. this should work well for most 3d pilots,i'll figure out some docile low rates for more relaxed flying.

CG... Umm slightly nose heavy then adjust to your liking,need to borrow a cg stand to get a rough starting point,typically 30-33% back from the leading edge of the wing at the root.

Build Supplys: PU glue.. gorilla glue,sumo,elmers ultimate etc.. cheap,bonds well,absorbs shock and is very resilent(i'll add some tips for application.. it expands about 3 times its volume depending on ambient temps so dont over do it). A box cutter with a sharp blade works well or an exacto. A four foot straight edge. Blenderm if you dont use robart hinges. A couple 2x4s or other device to keep the fuselage and wings square while the glue drys.

GRX-V1 48'' Demo At Hobby Town USA Orland (5 min 27 sec)

Demo at the shop with yakzilla
46'' GRX Yakzilla At Hobby Town USA (Quick Demo Flight) (4 min 27 sec)

GRX 46'' Yakzilla Scratch Built 3D Foamie Trying A Couple Props! (4 min 36 sec)

Really nice video by Grnd0 with his Grx V-1(the original)
GRX V1 (6 min 8 sec)

GRX Park Jet Fun Flying! (3 min 23 sec)

#2 appleflyer Apr 29, 2009 07:06 PM

ohh nice :cool: looks like it should fly great

#3 bighead93 Apr 29, 2009 07:07 PM

That is cool!

#4 steelydan Apr 29, 2009 07:13 PM

excuse the blunt question, Where did you get the cut patterns?

#5 Get Real Apr 29, 2009 07:20 PM


Originally Posted by steelydan
excuse the blunt question, Where did you get the cut patterns?

No patterns,just cut it out :o . I did do a rough trace onto another 8x4 sheet of owens for future changes though,made some small changes from the original cut. Really wanted to do all pull pull controls but didnt have enough odds and ends,it flys pretty well as is and i might make a couple more :D .

#6 steelydan Apr 29, 2009 07:23 PM

nice job

#7 justwanttofly Apr 29, 2009 07:35 PM

is there anyway that you could post some drawings and i could PDF and tile them for everyone.and post them is scratchbuilt fourm becouse that is one beauty and i would love to have it i know a perfect cheap motor for it ..show that at scratchbuilt fourms they will love it

#8 Get Real Apr 29, 2009 07:36 PM

Flight Video
Heres the video from when i flew it earlier today. I might change the aileron taper and or tips.. i always go easy on roll rates with foamys for some reason :o .

48'' GRX-V1 3D Foamy 4-29-2009 (7 min 26 sec)

#9 Get Real Apr 29, 2009 07:42 PM


Originally Posted by justwanttofly
is there anyway that you could post some drawings and i could PDF and tile them for everyone.and post them is scratchbuilt fourm becouse that is one beauty and i would love to have it i know a perfect cheap motor for it ..show that at scratchbuilt fourms they will love it

That would be cool,ive posted a few 3d foamys ive scratchbuilt in the past and people ask but i dont have anyway to cad them for others and i usually just do one off designs without any drawings. This ones kind of rough and would need some cleaning up but your more than welcome to take a look at it to get the demensions and make some plans from it as is,the cuts would need some cleaning up. I figure with all the hardware etc ive got about 25 bucks in it,a lot of people have stuff laying around though and could put one together and just buy the foam.

#10 steelydan Apr 29, 2009 07:47 PM

that would be very generous of you to share that. I would build one for sure. after all I have repaired my T28 so many times thinking , I should just glue up my own....

#11 kevbeer Apr 29, 2009 07:48 PM

I agree with Get Real - this is a well proportioned design for a 3d profile.

nice work dude.

#12 kevbeer Apr 29, 2009 07:49 PM

where can I score this "owen's pink" or atleast check out the specs?

thanks bud

#13 Get Real Apr 29, 2009 08:05 PM

Its owens insulation sheets. Can pick it up at home centers,it sands pretty well and shapes.. i used it years ago to make scratchbuilt boats and even back then i thought i could make my own planes from it but i didnt fly rc at the time. Blucore will work as well,when i decided id do a few designs again a few weeks ago they didnt have any blucore so i used this to get things started. Owens foam info here.

#14 Get Real Apr 30, 2009 07:25 PM

If Youd Like To Build One!
Im gonna cut another one of these out next week. I'll make a short list of what kind of hardware is needed to complete one and try to get a rough cg,throws and expo settings etc. The plane will fly lighter on 3s probally at 350 watts or so but in the video its propped for 500+ watts on 4s. If anyones really interested and local that could make plans from a template of the next one they can pick it up in exchange for putting out some plans for the rest of you guys. I could also do a couple short kits for locals if they supply the sheet of foam and can pick it up.

#15 justwanttofly Apr 30, 2009 08:30 PM

i wish i lived closer mapquest tells me 4 1/2 hours away i don't want to start up a frenzy but i would buy a set of traced out plans mailed to me if you had the time .lets say 15 bucks + postage.after seeing your video.

i really want that plane you are a genus or if you send the plans to me ill have my brother draw (i dont have a cad i just have a pdf and scale and tile program my bro is a cad master) it up and ill pdf it and tile it which ever way you want just pm me.and thanks for the offer wish i lived closer. did you use the 1/2 foam?

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