Old School Model Works: Raven ducted fan jet

[Michael]

The model is assembled, the radio and power system installed, and the nose steering system has been set up. These all took some time, but nothing was too difficult.

I still have to balance the model (it'll need some nose weight), and I have to set up dual rates and exponential servo travel.

The wing tips I designed look nice. My opinion.

[msatin]

Looks great!
Looking forward to the maiden

[davidk]

Beautiful... what a unique EDF.

[Michael]

Successful maiden. A few issues, all mine; not the plane.

Details and a few photos later.

[Michael]

I set up the moving surfaces' dual rates and the stabilization at the field. Although the V-tail was functioning properly, the stabilization system wasn't. It was correcting the 2 moving surfaces in opposite directions. I simply reduced the stabilization on the rudder-vaters to zero. No stabilization on the tail, but fully flyable nonetheless.

I did check the CG, but still added 3½ ounces of lead at the front. MISTAKE!

On the first take-off attempt, the model kept diving into the ground, whacking the nose wheel several times. Take-off was aborted.

I took out the lead, and tried taking off again. No problem. Nice take off.

Some light trim and reduction in throws was necessary, but within a minute I had it flying nice and straight. It was windy, with substantial cross-wind, but it was flying very smoothly.

With reduced throttle, it still stayed up and level, so in order to lower altitude, I had to lower throttle and add a bit of down elevator.

The bright yellow and red colours make it easy to see in the sky. The fan-shroud stayed on, just with the magnets.

I did a nice roll on high rates. It was fast, so next time I'll try it on medium rates.

I misjudged on landing, and landed about 10 feet before the runway/grass. The plane seemed fine, but the nose wheel was smashed back/in a bit. It's possible the difficulties from the first take-off attempt caused this damage, and only showed itself after the landing.

It's not a difficult repair, and I'll show it in the next post.

Overall, I think this is a good and stable flyer, and I plan to enjoy it.

Mark took the images.

[GuyOReilly]

CONGRATULATIONS!!!
Does this mean the CG on the plan is incorrect?
I assume you added weight to match the indicated CG location.
Inquiring minds wondering.

[Michael]

The plan was right. I was wrong.

[Michael]

Repair.

The nose gear mount and some plywood got damaged.

I cut sheeting from the bottom to expose the area, and cleaned up and cut out wood shreds. Then I glued the plywood former back in place.

Next step was to glue in some strong balsa square stock on the front and rear corners where the former meets the fuselage sides, and one across the front of the former, and 2 as braces to the front inside of the fuselage.

Then I glued the sheeting pieces back in place, and added another layer of covering to make it look nicer.

I may fiddle around with the V-tail mixing to try to get the stabilization gyro (black box) working at the tail.

Other wise, ready to fly again!

[davidk]

I've built more printed planes than balsa.  The printed parts all go into 1 box.  When the box is full of parts it's always a bit intimidating.  But, as I take out 1 part at a time from the box, the parts transition from pieces of plastic to wings, tails... you know.  As I start using the last of the parts I get this melancholy feeling.  I do see a plane but, as with the box, I feel a bit empty.

When I opened the Raven box and was met with 20+ sheets of balsa all nicely aligned, laser cut and labelled I felt the same apprehension.  And now, seeing the leftover bare bones of empty balsa shells I'm sad again.  The build is over.  I'm going to term this feeling FMS.  Finished Model Syndrome.

[Michael]

3rd, 4th and 5th flights today for my Raven.

I got my stabilization system working on ailerons and elevator last evening, and dialed rudder stabilization down to 0.

My plane balanced perfectly with a 4 cell 5000mah lipo battery pack.

Each flight was excellent. Good takeoffs, smooth flying, low passes, rolls, loops, nice slow and medium flight speeds, excellent gliding, and very nice landings. I was unable to stall the plane; it simply slowed down and glided forward.

[Michael]

For those interested, Dave figured out how to get all stabilization surfaces working correctly, with Corona brand servos. If you're using servos that rotate in a different orientation, then this may not work.

1. The port servo (left side from the back) must be plugged into the Elevator pins on the black box gyro stabilizer. The other servo starboard (right side from the back) is plugged into the Rudder pins. The steering servo is placed on a Y-connector with the rudder servo, preferably before the black box is plugged in; the Y-connector plugs into the receiver.

2. The rudder-vaters must have the servo outputs forward to the front of the plane, and the pushrods connected to the servo-arms oriented away from the rudder-vaters. See photos.

3. The black box gyro-stabilizer cannot be upside down. It must be facing up (pins and switches and pots up), pins to the rear of the aircraft. If mounted upside-down, or pins forward, the stabilization will not work with the V-tail or the nose-wheel steering.

4. The black box can be mounted with Velcro, on the plywood shelf, just behind the battery area (former F3).

5. The transmitter is set at normal; no V-tail setting, or anything. In my transmitter, the elevator function is reversed.

6. The black box stabilization direction switches are all down, except V-Tail and aileron.

7. The pots are set at approx. 40%.

Adjust dual rates as it suits the pilot.