Mike_Mc

I don’t know what the etiquette is in the 1/2A forum for construction articles so put me in line if I’m not. For lack of a better name I’m calling it Baby Grub for now.

- Type: Flying wing with single rudder
- Span: 24 inches
- Area: 216 inches^2
- Root cord: 11 inches
- Tip cord: 7 inches
- Engine: Norvel 0.061 AME

End of night 1. I found a couple micro servos (I’ll buy one more) so the radio layout has change from the photo and I think I can fit everything or almost everything in the main compartment. Maybe go with a fixed throttle if there’s an issue with fitting everything.

Lynn S

Looks good so far.

matchlessaero

The etiquette is that you must post more photos!

Looks like a pretty cool little project. What kind of airfoil are you using on it?

BMatthews

Oh yes, I like what I see so far. This is giving me some ideas for my compact "motorcycle" airplane. I need something that I can put on the back of my motorcycle so I can do TWO sports on those nice sunny Sunday mornings.

I'm wondering about this one though. The engine is meant to be back in that notch in the wing? With the radio gear behind it I think you're going to have some serious issues with getting the balance where it should be. Flying wings want their balance at about 23 to 25% of the MAC. On your simple tapered model the MAC will be the wing chord at the mid span point. That means your balance point is going to want to be pretty much right on the firewall. With the gear and the rest of the model behind that I think you'll need a LOT more space between the balance point and the engine. I'm thinking that you should not have put that notch in there at all and just put the firewall on the leading edge with no notch.

You've got enough model now that you can tape or rubber band all the stuff in place and get an idea of where it'll balance now before it's too late. I'd have a go at that and proceed based on what you find out.

And yes, more pics please....[sm=thumbup.gif]

Mike_Mc

The airfoil is a simple 12% symetrical and any reflex That's needed will be done with the elevators.

For the CG I knew it would be a problem figuring it out so I'm not using a standard engine mount. I'm going to be adding ply rails. The engine doesn't have to be right on the firewall and I'll actually be able to more it about 3/4 inch forward. I'll also put the reciever and batter back in the front of the wing if I need to.

I have a question you guys can help me with. How long will a Norvel .061 AME run at full throttle on 3/4 once of fuel?

Dukester

My Feedback: (31)

I'll have to hook mine up with a measure fuel amount, but a rough guess is maybe 4 minutes based on my times with a 2 oz tank. Depends on how you have it tuned and how well your clunk gets that last 1/8 of an ounce out.

But

Andrew

I'm getting 7 to 8+ minutes on a 1 oz. sullivan tank running flat out all the time.

Andrew

Mike_Mc

BMatthews is right. Ballance is an issue. Not a problem... yet... the firewall came off and was moved forward about an inch. This will give more room for radio gear. I've always loved non-standard designs and this is turning out to be a fun challange. More info later.

PS Baby Grub is a stupid name. More thought required.

colmo-RCU

Hehe, probably right on that one. I`d think you`ll get a dit more than 4 min, maybe 6 or 7. Anyway, why don`t you make flight easy and set up a throttle? I`m sure a little micro servo won`t make much of a space problem, and the advantages are endless. It will also give a lot more versatility to the plane.

Just an idea,
colmo

Mike_Mc

End of night 2:
- Firewall 7/8 inch forward and rails installed.
- Wing sheeted... mostly
- Fin built.

CrazyHerb

My Feedback: (1)

One concern before flight....if you haven't already flown it.
I balance ALL my flying wings at 16% then move back from there....
Standard practice for a flying wing CG is 16-20%
The farthest I have heard is 28%...but that was using a computer with optical stabilized active control.

As they always say..."Better nose heavy than tail heavy".
Wings have a tendency to be VERY pitch sensitive with aft CG's and you have PLENTY of surface area for "elevator" control on those elevons.

I have posted a simple CG diagram for wings on my page here:
[link=http://home.comcast.net/~crazyherb-rc/]CG on Wings[/link]

Check out some of my other sucessful projects and good luck...it looks like going to be a hoot to fly!

PS - I could have built that plane in 2 hrs out of foam...

CrazyHerb

soarrich

My Feedback: (98)

Yea, but it would be a foamy, I'd rather have a woody anytime! Looks really nice. He may be off on the foam, but he's right about the CG. My flying wings balanced at 21%, and I like them touchy.

Mike_Mc

CG, not an issue. Everything (Radio, battery, servos) will be infornt of the main spar. Still waiting on the servos.

I could have made it out of cardboard in 30 minutes. but it will stink more this way if it doesn't fly.