JHTitan, Thanks for the untiled plans. I generally scale down to 50%-66% of original and I think there should be no problem with these plans. I like to use HK 1811 2000Kv, AP05 3000Kv, or AP03 4000Kv motors with TP 250mAh 2S/3S bats. I'm able to make decent small park planes, with good scale speed. I'll post pics when I get started.

Ksqm

Thanks for plan. Mine is built. Added landing gear. It flies ok but is a little squirly in windy conditions.

Nextee, that is BEAUTIFUL!!! Great job, and I really like the intake and landing gear!! What is your wingloading coming in at? Wingspan vs weight? If you're flying a little light, it'll cause more instability in the wind. Also, with a KF wing, you might try putting wingtips on it. When I made the prototype, mine was very stable, until I hit one weird spot at the airfield. Do you have any flight video I could see?

Great work,
Tim

Originally Posted by grenadapult

Nextee, that is BEAUTIFUL!!! Great job, and I really like the intake and landing gear!! What is your wingloading coming in at? Wingspan vs weight? If you're flying a little light, it'll cause more instability in the wind. Also, with a KF wing, you might try putting wingtips on it. When I made the prototype, mine was very stable, until I hit one weird spot at the airfield. Do you have any flight video I could see?

Great work,
Tim

AUW of mine is 29 oz at this time. The wing has been a problem. I used hollow carbon fiber which isnt stiff enough. Originall tried slip ailerons and noticed ailerons were flapping so I moved servos to the wing. With the weak carbon fiber there is a lot of wing flex and I think the ailerons were allso snapping into position which made turning very sqirlly. I have added flat carbon fiber the length of the ailerons into the wing. Still need more test flights after this fix.
I am currently flying ailerons and elevators and am considering trying V-tail mix for ruddervators. Mine has the bottom rudder and steering now.
Have had issue of underpowered flying and poor performance from my cheapo batteries. This plane does not want to fly slow.

No video at this time.
Tim what do you mean exactly by adding wing tips?

Sorry to hear you are having so much trouble. Mine weighed in in the low 20 oz's I believe, so you'd need a bit more power for sure. That would also explain needing more speed. What size CF spar do you have in the wings? I used CF arrow shafts. .260" diameter.
The wingtips are just like a tiny v-stab, just big enough to cover the tip of the wing. On a KF wing, this helps prevent the vortex at the step from "washing out" the end of the wing. I usually make it big enough to cover the wingtip, with an extra 1/4" all the way around. It will take away from the look of the plane a little, but you can always take it off again later after getting everything tweaked.

I used 4mm carbon tubeing in th wing. Wanted solid but that was all the hobby shop had at the time. Might try the wing tips. Is there some documentation on this? I wonder if this "wash out" is the reason for the turns to be so different. I mean one turn might be nice and smooth the next turn will snap and the plane is upside down or spiraling towards the ground. Like a glitch in the servos.

Did a little research on washout and the use of wingtips and it explains the problems i'm having on turns.

Thought I would post some more my my Drone build. And share the technique I used for the front pod section as well as the air scoop. I recently started trying to learn to use Google Sketchup. It is very similar to a CAD program and if used correctly can produce accurate plans made from a 3D drawing.

By using Sketchup I was able to design a front Pod and using a plugin to slice the 3d drawing in 6mm sections. Perfect for bluecore since it is typically 6mm thick. In the first drawing is a 3d drawing of the pod section, showing the rear section that connects to fuselage. The second is a picture I just happened to take during experimentation with the slicer plugin. It shows all the 6mm sections stacked. The plugin will actually lay out each section side by side and numbered. Then a plan is printed out for cutting foam.

It took a little time to draw and experiment,but after printing the plan putting the sections together and shaping was easy.

I am not the best artist and I think the Pod section came out a little too bulbous or fat. But whats done is done. Here is the finished Pod. There is plenty of room for any electronics, cameras etc. All I have in mine is the antenna at the moment.
I still have wing tips to install, more tweaking and test flights then I want to add a camera to this bird.

VERY NICE STUFF, nxtee!!!! Absolutely beautiful work. As for you dimensions looking too bulbous, I think I know why. When I started designing the plane, I quickly realised how easy it would be to make it a Predator A (Downward nose and v-tail) OR a Predator B (Upward nose and v-tail, like yours). I made solid foam block noses for each on the bandsaw. No matter what I tried, I just couldn't get the Predator B nose to look quite right. In researching Predators, I found nasa's "Altair". It was the first predator B, which had the Predator A nose (my favorite) and the upturned V-tail (also my favorite). I left it there....for the time being. I later realiased why I couldn't get a good look of the Pred B nose. The fuse shape is wrong. The Predator A has trapezoidal fuse profile. The widest point at the bottom, and the downward part of the nose (I call it the chin) sits below that widest point. On the Predator B, the fuse has a hexagonal fuse profile, with the widest point just below center. That follows all the way to the tip of the nose.
I will soon be adding on to the plans with my originally intended nose, (sorry, the Pred A) it will be hollow like yours, but made of flat panels that curve in. I actually traced the facets of the foam block. I would have done this with the original, but I vaporized the nose before I got around to tracing it.

Tim

Originally Posted by nxtee4509

I used 4mm carbon tubeing in th wing. Wanted solid but that was all the hobby shop had at the time. Might try the wing tips. Is there some documentation on this? I wonder if this "wash out" is the reason for the turns to be so different. I mean one turn might be nice and smooth the next turn will snap and the plane is upside down or spiraling towards the ground. Like a glitch in the servos.

Did a little research on washout and the use of wingtips and it explains the problems i'm having on turns.

My Predotor did the SAME THING a couple times. Always in a banking turn. It felt kind of like the tail was coming around the plane, but I always recovered. I too, did not have wing tips on it. My next one will be all EPP, and WILL have wingtips.

Have you read through the KF discussion threads?
https://www.rcgroups.com/forums/show....php?t=1117276

Tim

Thanks for pointing the discussion forum out I was unaware it existed.

Just an observation. There seems to be a lot of surface area in front of the center of gravity. Maybe there isn't enough tail to keep the plane pointing forward. And then compound that with the prop pushing on the tail while going around a corner. If there is not enough force holding the tail to the back it is going to get squirly.

This is something you have to watch out for in model rockets. You have to make sure the center of pressure is well behind the center of gravity so the force of the rocket engine doesn't turn the rocket over. (exciting but not desired)

An example would be pushing a pencil across a table as opposed to pulling it.

2 possible solutions: more surface area on the tail or move the wing (and center of gravity) forward. Both mess with the scale appearance but should improve stability.

So far I have added flat carbon fiber spars to just past the ailerons to decrease wing flex. i have only had 2 flights since this modification and it flew a whole lot better. There werent any snap spirals downwards on turns. It has been so windy here around Galveston that havent flown it much. So far I think it was the wing flexing causing some aileron problems. Still might try wing tips next. Just need some more fly time.

Originally Posted by grenadapult

I started out with the ever-classic 2409-12 and 20a ESC combo from hobby city. Its being powered from a 25C 1300mah 3s. The prop is an 8x6. That should be running me near 30oz and 60mph, but if you listen closely, you can hear that the motor is just about shot. I was hoping for a glorious farewell to that old friend, and I think the Predator did just that.
I plan to try a 2212-10 next, though I' having a terrible time finding good specs on what its capable of. Worst case, I still have a 2409-18 and 11x7 prop. Very similar performance to the aforementioned.

Hi, I also have completed the airframe of my predator. Entirely constructed of Elmers Foam Board. I moved the ailerons outboard to the end of the wings, and I am going to add some landing gear too. But I am really on a budget and I would like to use the power setup from my other airplane (FF-22 Elmers Foam Board also). It is a Turnigy C3530 1700kv motor, Turnigy Sentry 40A ESC, and Turnigy 11.1v 2200mAh 3S 35C Lipo. And what size prop should I use?