Red Tailed Hawk glider

[teflyer]

Everything looks good! The only things that worries me is that even though there is a tail, the tail is so close to the CG that basically it probably could be considered a flying wing. The KFm3 tries to mimic a real airfoil and flying wings with standard airfoils need reflex to fly properly. Therefore, flying wings with KFm3 needs reflex to fly properly. The reason for that, in my opinion, is that with an airfoil, air is directed down. This pushes the back of the wing up. Without reflex, the wing would go straight down as was seen in my testing. The reason why the KFm2 does not have that problem is that the supposed vortex already ends before the wing ends and the airlow straightens out so that the air at the end of the wing is not deflected down. So, in my opinion, I would either make more room on the bottom sheet of the wing for the air to stabilise or have some uptrim on your elevator when you fly.

Also, I agree with colorex that elevons would probably be better.

Also, where are you going to put the vertical stabilizer? If it is going to fool the birds into thinking the plane is also a hawk, I would use a V tail as colorex suggested or a vertical stabilizer made of clear material such as plastic.

 

[earthsciteach]

I don't have confidence that using the tail as elevons will provide enough authority in turning.

And, yes, placing servos far enough back to attach directly to the servo arm will move the cg rearward. But, I want to eliminate control rods because they could injure the hawks if they do attack the glider. I'm considering using fishing line with a bell crank type arm/control horn.

The CG is going to be a huge challenge with this glider.

 

[earthsciteach]

I can overcome the pitching moment of the airfoil by trimming the tail up. For a rudder, I plan on attaching a vertical stab on the underside of the glider. It will be as small and light as possible. From videos I've seen, birds attack from above, so it shouldn't be a turn off for them.

 

[teflyer]

I believe colorex and I mean elevons on the wings themselves.

also, since you do have a fuselage on the bottom of the plane, you could put the servos and music wire on the bottom of the wing/fuselage... and the servos probably will not get stripped because the fuselage protects the servos.

 

[colorex]

The only point to consider is that we are talking about a glider, and if it needs to be uptrimmed by huge amounts, it's only going to cause drag, which you don't want on a glider.

 

[earthsciteach]

A full grown hawk will rip through this thing like its wet toilet paper. And we have a couple of BIG ones! I'm not worried about the electronics. Any hard, sharp objects, such as control rods, pose a big threat to the birds.

 

[teflyer]

Also, another point to consider is if the flying bird can be considered a flying wing.

if it is worth anything, I would suggest slightly a KFm2 over a KFm3. just had a better experience with it. A KFm2 is also lenient on the CG placement I believe.

Must be really cool to see those birds soaring. We have a couple of hawks down here that show up whenever it is warm and windy. Pretty awesome creatures.

so, are you going to do something such as a pull pull system with the fishing line?

 

[flylow]

you should bling it out with feathers

 

[earthsciteach]

Ha ha! Tar and feather it! It will get a good paint job to make it look like a hawk.

Yes, going with the pull-pull system.

 

[teflyer]

Have you decided on which airfoil you are going to use? Have you decide to use High start or use a tow plane?

 

[earthsciteach]

Still putting it together. I have a set of KFM-3 wings made. We're at my parents house in Delaware for a few days over spring break. Chilling at the beach and generally relaxing. I won't get back to the RTH glider until Tuesday.

 

[teflyer]

Nice! Have fun over at the beach!

Friendly notice: Can you clear some messages from your PM inbox? I am not able to send any PMs to you because of that. Thanks!

 

[earthsciteach]

Will do!

 

[anthonykoeslag]

I've been interested in this idea for a while now, but I only found a few videos on RC bird gliders (without a vertical tail)
You might find some inspiration from these:

and