Thread Tools
Jul 28, 2020, 02:58 PM
Spychalla Aircraft LLC
Thread OP
Build Log

XF-85 Goblin, 64mm EDF, "The Flying Egg"


Resurrected this 12 year old project. 1/11th scale XF-85 Goblin. I need something entertaining. I have never seen a scale version fly successfully. Maybe Petronio had success? I decided stability could be enhanced by using a flying wing airfoil. The Selig 5010. Placed it on the fuse at +1.7 deg. Power will be a 64mm EDF on 3S 1300 mah. Going for elevons like a Zagi. Just stationary fins on the fuse. We will see!
Sign up now
to remove ads between posts
Jul 28, 2020, 03:06 PM
Spychalla Aircraft LLC
Thread OP

XF-85 EDF Mounted


XF-85 Progress. Glued wing halves together and mounted EDF at 0 deg., wing is +1.7 deg. X tail surfaces are at 40 deg. angles. So strange! Everything on this "Flying Egg" is odd. The 4.7 deg. anhederal just seems like a bad idea. Why would they do that? It is madness.
Jul 28, 2020, 03:08 PM
Spychalla Aircraft LLC
Thread OP

XF-85 Vac Formed Fuse, 1st attempt


XF-85. Did some quick vac-form pulls as a quick trial. I need to get my styrene sheet hotter and space the plug up so the radii on the split line disappear. It is a Goblin! Ordered a new AURA 8. My son Zach is doing the programming and first test flights. Hmm, balance point calculations are coming soon.
Jul 28, 2020, 03:18 PM
Classic jets rule
AIR SALLY's Avatar
Cool project. Seen a vid of a glow powered version , seemed pitch sensitive. Good luck
Jul 28, 2020, 03:52 PM
Spychalla Aircraft LLC
Thread OP

John Boren Comments on XF-85


Air Sally, That YouTube Video was of the ducted fan version of the XF-85 that John Boren built and attempted to fly back in about 2005. Here are his comments regarding it:

You can see a video of mine flying and crashing here. http://www.johnboren.com/html/goblin.html I believe the reason it didn't fly is because I only used to two upper ruddervators for pitch control. The real one used the bottom control surfaces for pitch control as well. I believe at any angle of attack the upper surfaces were being planketed by the fuselage. Turning it into basically a flying wing should work for you.
Goblin
JOHNBOREN.COM
Goblin
Jul 28, 2020, 05:29 PM
Pro Hoarder
turbonut's Avatar
Cool project...lots of technical challenges to over come
Latest blog entry: In flight
Jul 28, 2020, 06:32 PM
Onward and Upward.
CatManDu's Avatar
Neat project. How will it be recovered? Belly landing?
Jul 28, 2020, 11:39 PM
Registered User
AntiArf's Avatar
Great subject and good to see you taking it on. Researched it for hours as a potential build subject in recent times. Johns build/video showed that it certainly is doable.
Jul 29, 2020, 11:20 AM
Mike
i12flyrc's Avatar
Jul 31, 2020, 05:41 AM
Spychalla Aircraft LLC
Thread OP

XF-85 Goblin Fin Location on Plugs


XF-85 Project. Located all the tail feathers on the Egg at 0 deg. incidence. Not easy as everything is curved. I had to think about it for a while. I sacrificed a vac formed shell to use as a template. Then transferred raised areas to the vac form plugs to locate the fins. Built a canopy plug. Added 3/8" spacers behind the plugs to get a good straight edge on center line. Should be able to pull some new parts today.

Yes, it will be belly landed. Just like the real one when it didn't successfully re-hook the trapeze.
Aug 07, 2020, 11:17 PM
Need 4 Speed!
pdawg's Avatar
Very cool. Watching with interest!
Latest blog entry: original Y/A F-18 Kit
Aug 15, 2020, 10:27 PM
Beer is proof that God exists
FoamFlyingJoe's Avatar
Oh, I’m definitely subscribing for this one!
Aug 18, 2020, 06:01 AM
Spychalla Aircraft LLC
Thread OP

XF-85 Goblin


I have been struggling to get the tail fins on the egg shaped plug at 0 degrees incidence. I did not have them right. It finally dawned on me that I could mount the plug on a spit located through the centerline and rotate it in front of a laser level. Ahh, I now have them located with confidence. I don't need those tail feathers driving me up or down.
Aug 18, 2020, 05:00 PM
Classic jets rule
AIR SALLY's Avatar
Great idea....might as well use technology when you can. They use it for fullscale stuff. Theoitlite amazing how accurate those are and the operters are like mathematical wizards
Sep 20, 2020, 08:00 AM
Spychalla Aircraft LLC
Thread OP

XF-85 Goblin Gets a Canopy and Aura 8


XF-85 Goblin update. I vac formed some new fuse sides with confidence the empennage fins are now at 0 deg. Vac formed a canopy. Now working on the guts which will be all based around an Aura 8.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
XF 85 Goblin Crash John Boren Crash Discussion 36 Mar 06, 2019 03:52 PM
Video XF-85 Goblin EDF-40 Maiden sudovod Electric Plane Talk 10 Jun 10, 2010 12:41 AM
Question XF-85 Goblin for EDF40? david_r2ese Foamy EDFs 8 Mar 27, 2006 01:24 PM
Jet design contest XF-85 Goblin kennypinkerton Electric Ducted Fan Jet Talk 13 Mar 02, 2006 11:59 AM
MDD XF-85 Goblin??? Axel Electric Ducted Fan Jet Talk 6 Mar 02, 2006 11:50 AM