RC Groups

RC Groups
    Nurflügel
        Discussion FZ3 build: Flying wing with landing gear

#1 vincent123 Nov 03, 2012 01:04 PM

FZ3 build: Flying wing with landing gear
 
4 Attachment(s)
Hi, just finished my prototype:

Before building the FZ3, i decided to build a prototype first, as there will be a few differences with the FZ2.

The PT is build from 3mm depron, glas covered and painted wih "RC colors", 4w HET motor, 3cell. Sizing of the PT is made as such, so that the cubic wing loading is the same as for the original FZ3. Aileron and flap are resized in order to have a representative flying experience as would be with the FZ3.

I simplyfied the front wheel, it's more like a skid, not streerable, just to find out if it is possile to take off with this odd setup (cg in the center of the 3 "feet" and the winglets-feet being far behind the cg).

I made some attempts to make the skid a retract with a servo, but the forces are huge during takeoff, the frontskid itself and also the servo broke on several occasions. Decided to have a front skid without retract. This turned out fine, the wing has to make a nice speed, before it's able to takeoff. This is due to the odd setup, the wing cannot be tilted to catch more air. The skids are designed to have the wing at an angle of attack of 6° during takeoff.

Having 30° of sweep, with winglets upside down, showed me that the wing is stall prone at low speeds, especially during landing: the ailerons lack authority at low speed. In order to keep the design clean, I decided not to add top winglets, but installed fences instead. These should be a able to limit the spanwise crossflow, which induces the stall behavior. Yet to see if this change turns out as expected.

http://www.rcgroups.com/forums/member.php?u=271334

#2 potshot Nov 04, 2012 11:35 AM

Vincent, that looks so COOL! Even without the LG the lines are great. I like that underslung fuse and the dropped winglets. Actually, it would look as good inverted. DO you have any pics that show the fences?

... Oops, just saw your blog with the views I requested, so as Emily Litella would say, "Never mind." The video there indicates a beautiful build, too. This plane gets more and more interesting.

#3 vincent123 Nov 04, 2012 01:46 PM

2 Attachment(s)
Hey, thanks Potshot, nice to hear you like the design.

For now, the front skid is left as such, the retract function was great, at least it worked nice on the workbench. But during takeoff, it cracked.

I leave the premiere to the FZ3, which will get a proper retract will steerable wheel. I know it will never look as cool as with he skid....hmm perhaps i should rethink the skid.:o

The skid of the PT can be removed for landing in high grass, while being handtrowed.

#4 potshot Nov 05, 2012 11:23 AM

So were the fences as effective as you anticipated?

#5 vincent123 Nov 05, 2012 02:53 PM

don't know yet, waiting for better weather conditions

#6 potshot Nov 05, 2012 07:55 PM

Quote:

Originally Posted by vincent123 (Post 23190523)
don't know yet, waiting for better weather conditions

I know the feeling. :( Long time until Spring.

#7 vincent123 Nov 11, 2012 11:58 AM

Tested the wing fences today, it feels a bit more solid, more authority during landing. Nevertheless, ailerons seem a bit too small for a swept wing, no prop at high speed, but while landing i need more throw.

#8 vincent123 Nov 12, 2012 02:36 PM

Some footage of a takeoff:

Flying Wing With Landing Gear (1 min 48 sec)

#9 potshot Nov 12, 2012 04:15 PM

1 Attachment(s)
Very cool, Vincent. BTW, what are these?

#10 vincent123 Nov 12, 2012 04:22 PM

Just two pins to fix the front landing skid :)

#11 potshot Nov 12, 2012 07:57 PM

Ah. Thanks!

#12 vincent123 Jan 04, 2013 09:20 AM

3 Attachment(s)
Proceeding to the FZ3 build, based on the Prototype

#13 Jon Snow Jan 04, 2013 12:14 PM

:popcorn::popcorn:
Still using a skid?

#14 vincent123 Jan 04, 2013 02:20 PM

3 Attachment(s)
Nope, plan is to use a full option spring loaded retract, steerable, and hidden behind a kind of "door" (or how do you call that?).

Still having the trailing skids, which are actually the up-side down winglets.

#15 vincent123 Jan 19, 2013 12:55 PM

1 Attachment(s)
1 face sheeted, 3 to go!


All times are GMT -5. The time now is 10:02 PM.