EDF Predator UCAV. It Flies!

Posted on 12/6/2009 12:19:21 AM
Author: Chip

It Flies!  

A continuation of the build post.

I must say, this is a REALLY nice and easy flying jet.  I forgot to have someone radar gun it, but I *think* it's around 100mph.  My thrust tube exit diameter is about 1/2inch smaller than the diameter of the hole in the back of the jet and measured at 81mm coming from the 96mm Himaxx fan.  Not sure where that falls in terms of thrust to speed, but it felt like it had more thrust than actual top speed.  Take-offs into the wind were pretty uneventful, just wait for it to have enough speed and pull up gently.  On my third flight I hit an undulation in the grass and it lifted prematurely (actually BOUNCED into the sky about 6 feet).  I lowered the nose and just kept the throttle on it and it picked up enough speed without falling back to the ground.  

The first flight video did not come out unfortunately - a little confusion over when the camera was recording and when it was in standby, but the take off and landing was....interesting.  The take off started out normal, but required more ground than any other plane I've flown (this is the biggest I've flown to date).  I pulled up once it felt like it had enough speed and it shot right up into the air perfectly.  It started to bank to the right...an angle so far right, Fox News would have been embarassed.  I gave it some left aileron, only to have it whip over to the left as if I just over corrected!?!  I should note, I don't fly any of my aircraft with expo, I don't like the non-linear feel at all.  However, this was more of a case of the high rates being WAY too high.  I clicked over to low rates on the ailerons and immediately this bird transformed into an angel.  It was like a whole new experience. It required 9 (out of a possible 20) clicks of trim on the elevator to keep the nose up and 4 clicks of left aileron to keep it level, but once those were dialed in, the jet flew perfectly level.  I'm 99% sure I didn't breath at all during the flight, so my recollection is a little hazy, but I do remember noticing the plane likes to climb, and not drop, in a turn.  I should note, I the V-Tail is setup for elevator only, I couldn't figure out how to properly set it up to do rudder as well - and have it control the nosewheel.  So I think if I had control over the rudder, the turns would have been a lot more coordinated.

After a few circuits, I decided I better bring it in.  What felt like an hour of butt-cheek clenching flying was actually only two minutes of airborne flight.  I set the plane up on the downwind leg and cut power at about 150 feet AGL, had it glide forward about 100 feet, banked left for about 200 feet and then lined it up with the runway (read: the strip of grass where it's mostly burnt out). I had traveled about 350 feet, but had only dropped about 25 feet in altitude by the time I crossed the beginning of the "runway".  No worries, I have about 500 feet to work with......man this plane looks cool flying by, power off, 75 feet in the air, with no intention of it coming down any time soon....

Well, I thought...this is going to be a long walk to go pick it.......oh crap, there's a wooden fence, followed by a swingset, followed by a house, approaching RAPIDLY....and I'm still 20 feet off the ground!  I was either about to answer the age old question, what happens when an immovable object hits an unstoppable object, or I was going to have to plant this plane into the ground manually.  I opted for the latter to avoid some sort of black-hole, anti-matter sucking, nuclear explosion and provided a little down elevator to coax it down.  What insued was quite possibly one of my best landings - I mean, it was greased.  However, this 8 pound bohemeth first touched down about 50 feet from the fence, on a downhill roll and now I had to worry about crashing through the bottom of the fence as it still had a lot of momentum.  Luckily, my laziness in not reaming out the holes on the wheels to properly fit the axles paid off, and the built-in "brakes" brought the plane to a stop in a Ferrari pouncing 35 feet; leaving a full 15 feet from a very embarassing crash and a Saturday afternoon full of Home Depot runs and fence fixing.  Good fences make good neighbors?  Well, good brakes mean you can keep on living without introducing yourself to your neighbors.  Perhaps a lesson for Tiger Woods too.

Overall, I'd say it was a fantastic flight for a plane I truely did not expect to have a controlled landing with.  It was a pain in the ass to build, nothing fit right, CG was WAY off in the manual, and it was my first venture into "big" jets.  I swore I'd never buy another plane from NitroPlanes, but after this experience, when all is said and done, they actually don't ship a terrible product.


rafe on 12/6/2009 8:26:06 AM wrote:
Impressive plane, Chip. And impressive flying. Must admit, when I first hefted that airframe last weekend, I was skeptical, but I'm a wimp. This much I knew from the get go: if anyone in our group was gonna pull this off, it was going to be you. Bravo!

Alex on 12/6/2009 5:32:48 PM wrote:
I was waiting for the pilot's report. Well done!

Fettah on 12/7/2009 11:41:00 PM wrote:
This is a whole new level of flying at Mitre folks. This one is going to be a though one to outdo. Super job Chip? What is next to wow us?

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