Does anyone have the UFO plans?

Thanks, Tim

What's your pleasure - wood or glass? I have plans for the full size wood UFO plus full & 1/2 size for the glass UFO. It won't let me post them here because they are very large but I can email them to you. I also have a PDF of the original RCM building article. Let me know.

Jim

Yes.

Going to build a UFO?

Brian

Wood please, but I'd like the glass for extra resources. It's actually for a local modeler. He of course had one in the day and I'm trying to get him interested in pattern. I was supposed to make a DB for him and I just got it done and he said he bought an ARF already (I know, not the same) but he'd like to build a UFO. He's a big scale competitor so I know he knows how to build. That's how I came to owe him a DB, I bought a Jerry Bates (I think) Bearcat with GT80 in it from him and he made me a good deal and I said I'd make the DB. Ok, over-share!!!

Anyway, between the SPA events and the CPA event I'm hoping for on November 2 maybe he'll come on out and have some fun.

Do you guys have them scanned already?

Tim

He could just buy the wood kit from Bridiairplanes for the UFO.

http://www.bridiairplanes.com/hangar/ufo.html


Jim

That would work. I may be making the wings and stabs from foam for him but the fuselage he may build.
I'd still like the plans for my comparison on the DB though.

Thanks,
Tim

Yup - PM me your email address and I'll send them along. I'm leaving town Friday morning for the Chattanooga SPA contest, so get the addy to me before then or it'll have to wait until next week.

I emailed you,

Thanks Jim.

pm'd you.

Brian

Brian/David you have PMs.

Let me know if you were able to work with the files.

Brian

p.s. I sent you a download attachment from Adobe. I think that will work better.

Thanks Brian, everything came out great.

Tim

Tim,

Email Replied.

Thank Jim

The guy building it doesn't post on forums but I'll sneak over and get some pics if he starts building.

Tim

For those curious here's the comparison of the DB and UFO.

I am always interested in these things.

Tim,

Show the differences in the wing with the sweep and dihedral, and horizontal with the anhedral verses flat stab....

Then compare the UFO fuse to the XLT...



Brian

The horizontal looks the same other than it's anhedral on the UFO. The elevators are cut away a bit more which is what we were already doing with the DB.

The wing is 1" longer and swept back on the UFO

Edit: the dihedral on the UFO is 1.317 per side and the DB is .67 degrees per side. This is all measured from the wing tips which is odd because if you round them off like the plans show they don't touch the table.

Looks like the stab has been raised on the UFO to just above the thrust line. That may be the reason for the anhedral stab???

Anything else I'm missing?

The airfoil on the horizontal is substantially larger.. imo. But you pretty much got it. Slight changes, but tell the tale of the change in flight demands.

I am thinking the anhedral might offset the roll coupling caused by the dihedral in the wing. I have to wonder if the purpose of the anhedral was more to do with the genre than the demands of physics. I could be wrong. It would be cool to hear Bridi's explanation.

I saw the XLT fuse layered over the UFO once... It might have been one of Roguedog's posts... I was amazed that the fuse and stabs were virtually the same on both airplanes.

Thanks!

Fun stuff.

Brian

Looks like the UFO stab is thicker. I know the P7 and Atlas as well as others had thicker stabs than the DB.

I think you're right about the anhedral and the wing incidence issue. But I've been told it might have been phooey.

Tim

Any classic design that had pronounced stab anhedral, also had significantly more wing dihedral. Absent that, the model would not knife edge very well. Anhedral designs also typically have stabs placed at a higher draft because the anhedral lowers the "effective" position. The prime example of these extreme angles in di/anhedral design is Hanno's Magic. The counter design concept would be Naruke's Aurora (thin flat stab and rather thin flattish wing coincident and close to the thrust line).

Bridi's idea behind the thicker stab airfoils as the tail moments increased (UFO, XLT, Escape) was to lower the stall speed on the surface allowing it to produce lift at slower air speeds. I guess the concept was to have the model fly on the wing and the distant stab.

At least this is my understanding.

David

Edited for fuzzy math. The UFO has about 2.65 degrees of dihedral and the DB is around 1.35. I was cutting a wedge for the new DB and it was too big when my band saw was set at 2 degrees and I found the error. :-)
The photo I showed is showing the anhedral stab of the UFO and the dihedral wing of the DB.