Ritewing Show and Tell

[a_marmot]

OK y'all. Here's some snaps from a couple of different works in progress:

1) A zephyr with unusually large motor and electronic gear. Uh, wait a sec. 30" wide? What?



That's right folks, not a zephyr at all! That's a FPVised IYF 30. Crazy, eh? Indeed, just getting the layout to work on this thing has been a challenge. And in all probability it will end up being a flying brick. But a man can't just sit around. (We'll see if it actually flies in a few weeks....)

2) Slotted flaps incorporated into the wing of 72" zephyr to-be. Had to rig my own hotwire to make them - more details in a few months.



Enjoy the pics!

[brosius85]

wow

just quietly i think "brakes" is what you can put on zephyrs... as you need up elevator to counter the down flap it is basically brakes. keep us posted though! looks like a good build. hope it goes smoothly bro

[jimmaplesong]

Lookin' good! I did some FPV with an IYF44 when I was starting. I can't wait to see how fast you have to fly the 30 to keep her in the air. Should be a blast. What size batteries are you going to use?

[GregSilver]

What kind of hinge is that on the flaps?

[a_marmot]

wow

just quietly i think "brakes" is what you can put on zephyrs... as you need up elevator to counter the down flap it is basically brakes. keep us posted though! looks like a good build. hope it goes smoothly bro

Well, yes and no. The flaps are located on the inboard side of each wing, where the c/4 point is mostly in front of the CG. Thus the increased lift actually creates an upward pitching moment to counter the downward moment around the c/4. Based on numbers from the Theory of Wing Sections, I worked out the approximate changes in lift, drag and moment. Although some upward deflection of the elevons will be needed, it's not very much. The overall increase in lift *should be* substantial (as well as improved resistance to tip stalls at low speed). We'll see if it works in practice as well as it *should* (theoretically...)! Stay tuned...

[a_marmot]

Lookin' good! I did some FPV with an IYF44 when I was starting. I can't wait to see how fast you have to fly the 30 to keep her in the air. Should be a blast. What size batteries are you going to use?

2x 2100 2s, stacked in series as 4S. This way they can lie flat, and can be put in an arrow configuration up front like a zeph. It's way overpowered (35A scorpion with 9x6 prop), static thrust is about twice the all-up weight of the plane. The plan is to take off vertically like a rocket, then level off when it approaches cruising speed (about 30 mph).

[a_marmot]

What kind of hinge is that on the flaps?

The hinges are made by Robart, and are (incorrectly) titled "Fowler flap hinges." Despite the title, the hinge action is actually that of an ordinary slotted flap, not a true Fowler flap.

[GregSilver]

wow...expensive little buggers.

[a_marmot]

wow...expensive little buggers.

$17.50 a piece on Amazon (not so bad when you consider all the electronics riding on the plane).

My biggest concern is keeping the flaps from dragging on the ground during landings, not sure how best to do that yet. Maybe just retract them before touch down? (this adds human error factor). Or maybe an additional pair of coroplast fins hanging down where the wings join the center section? Other suggestions?

[a_marmot]

Progress photo: IYF30, FPV style. Getting closer...

Note the coroplast-less equipment bays. I decided to try just laying out the equipment in individual cavities in the foam, and laminating to hold in place. The only exception will be the batteries, which will sit flush in open bays.