Predator "Two flights to disaster"
 

Hi Guys,

I flew the Predator for the first and last time today.
After reading a thread on here I decided the Predator was the plane for me.
I wanted to try combat for the first time this Summer so I bought the kit.
I took my time to build it right, per the instructions.
Norvel .25 BB engine
HS225 MG for Elevons
HS81 MG Throttle
6 OZ fuel tank
250 Mah Battery
Ultracote covering
A whole can of 3M 77 spray adhesive!

I mounted the Elevon servo in the center of it's length.
Battery under the fuel tank
Receiver beside the fuel tank

I put the engine all the way to the end of the mounting rails and it was still tail heavy for the recommended C/G
I put on an aluminum prop and taped weights to it until it balanced. I needed 66.3 grams (2.3 oz.) more weight to get the proper balance. I took the calculations to work and turned a brass prop nut. It weighed 107.9 grams (3.8 oz.), just right to allow the engine to be moved back a 1/2 inch or so.

Aileron throws 1/2" LO 5/8 HI
Elevator throws 3/16 LO 5/16 HI

Well, now to the good stuff.
This being my first flight for this type of plane, I figured the first launch wouldn't be pretty.
I Set the rates on low, run the throttle up to about 3/4 and it felt like it had good pull.
I gave it a gentle toss into the 10 to 15 mph. wind. It took off at a nice climb rate and gained altitude quickly. I gave it a few clicks of down elevator and a couple of left aileron to get full power level flight.
Man, I thought, this thing flies great! I'm about 4 or 5 minutes into the flight now, the engine seems a little lean, so I cut the throttle, kill the engine, and head for the runway. The plane touches down and slides to a gentle stop about 20 feet from my feet. I get a nice round of applause from guys watching and I'm thinking, is this great or what.
A 1/4 turn richer on the needle valve, fire it up, and were off again. This take off is better than the first since it is trimmed now.
I make a couple of high speed passes down the runway, less than 5 feet off the deck at some points and I'm thinking, this thing flies nice. Now let's try some loops, they aren't very tight, no problem, switch to high rate, thats much better. Now I do a string of outside loops followed by 6 or 8 inside loops with no snap tendencies. By now I have gained a pretty good altitude, so I throw it into a power dive, it looks like a hawk diving for a rabbit. A couple of seconds of dive, now this baby is cooking.
All what the heck, lets try full up elevator, big mistake. I heard a big flutter and it looked like it was trying to tie its self up into a pretzel. Now what, this doesn't look good at all, chop the throttle, were about 50 feet from the ground, then it straightens out and starts flying again. Now it is all out of wack and I have to fight the sticks just to keep it in the air. I better land, so I cut the throttle, but it won't go less than 1/2. After 20 to 30 sec. the engine quits and it slams into the ground.

Total flight time, less than Ten minutes.

Well, better go survey the damage. The engine is about 25 ft. from the plane, it looks o.k. but the throttle barrel won't close.
The plane has crease through the top of the wing and the elevon and trailing are broken in half about 4'' from the center. The foam is broken in half from the leading edge to the spar and open on the bottom.
If I tried to fix it to fly again it would always be in the back of my mind, how much can it take before it happens again.
With that thought, I ripped out the radio equipment, cut it up in little pieces and threw it in the trash can.

There was no warning is the instructions that this could happen!

Is this some thing that has happened to other people, or is this a rare occurence.

Maybe the guys at tufflight will feel sorry for me and give me another one, He He.

Any other suggestions? whats tougher than a Predator?

Gary V.
(Combat pilot wanabe)

Predator "Two flights to disaster"
 

From the sounds of it...do you think ANY plane would walk away from that without a scratch? Tougher than a predator? Good luck. As tough as a predator AND one that is as competitive and as inexpensive as a predator? Good luck. They are Very sensitive to too much elevator throw as is any flying wing. I set mine up with a high rate just below what will make the plane snap out of a loop, and low rates at 15-20% less than that. C/G is extremely critical and making it nose heavy, even a little bit won't help matters, just make it nose in when the throttle is cut (bad thing).

Yea, it's obvious that I am a fan of the predator, but you will be hard pressed to find anything BETTER for the price/performance/toughness/speed of one. (I bet I'll get slammed for these comments). It's equal? maybe. But better?

Sorry to hear of it's untimely demise.

Predator "Two flights to disaster"
 

Hi Ti Guy,

The structural damage wasn't done when the plane hit the ground, it was done when the wing folded in flight.

At 5/16" elevator throw it didn't snap out of a loop.

I'm sure that the full throttle dive and full up elevator was a
recipe for disaster.

I am curious to hear if the wing folding in flight has happened to other predator owners.

It broke where the receive hole was cut, about 4" to the left of center.
Maybe I didn't have the covering tight enough.

If I come to find out that the wing folding was a rare ocurrence,
I may get another one.

It really was a blast to fly, even if it did only last 10 min. or less.

Predator "Two flights to disaster"
 

The only time that I have folded the wing on a Predator was after it went through 8+ midairs. The spar apparently cracked on one of the midairs and it folded itself up into a neat little ball.

I've built 9 Predators over the past couple of years and I have nothing but good things to say about them and TufFlight. The TufFlight guys stand behind their products. Drop them a line and I'm sure that they will make it right.

Just from the sounds of it, perhaps the lexan spar was not sufficiently adhered to the EPP foam. Liberal doses of spray adhesive on both the spar and foam are necessary for a good bond. On top of that, it is a good idea to run strapping tape over the spar joint top and bottom of the wing.

You didn't mention what type of covering you used. Was it ultracote or oracover? That covering is more elastic than Monokote.

Did you take a picture of it before it blew up? :cool:

Predator "Two flights to disaster"
 

Gary,

Did you get the bi-directional strapping tape and apply per the instructions? I recently built a Predator and have been very impressed with its performance. I think it took too much work to build for a model with a short life expectency, but that may just be my opinion...

I too suggest that you call the guys at TufFlight. They were more than helpful when I called with building questions.

Cheers!

Galen

Predator "Two flights to disaster"
 

Yes,

I used ultracoat covering and bidirectional strapping tape.
Full length of the span top and bottom, and over the leading edges. I also used it over the receiver.

the strapping tape didn't break it folded with the wing.

I took a couple of photos with a disposable camera just before the flight, but I don't know how to get it from the scanner to this forum.

Predator "Two flights to disaster"
 

I had the same thing happen to my Version 1 Predator (There have been a few revisions to the kit since then). I put it into a powered dive (big Mistake!) and it did it's best impression of a seagull trying to take off and then snap! It broke in two and fluttered down nice and soft! I was so enthralled with the oscillations of the wing that I never backed off the throttle. My wing snapped in exactly the same spot as you described. I shrugged my shoulders picked up the pieces, went on-line that night and ordered another kit, I Love a challenge so I was not about to give up on the kit! I built the second one in 1/2 the time it took me to build the first one and now I absolutely love this plane!!! I actually use it more as a sport plane than a combat plane (this is probably because I am still not very good at thewhole "Combat" thing yet) I love just showing up at the filed taking the plane out of the car, starting her up and flying long before most people have their plane assembled! you might want to give the plane another chance before giving up on it!

- JK

Wing
 

Your mistake was proably due to A LONG, power dive, just to much air speed most of the combat i have done is in a box in front of the runway so you don't build up that kind of speed, i have a floyd and I really like them, I carbon fiber the leading and tailing edges top and bottom, as well as laminating the spare , use the straping tape with out covering I glassed the fuse front to back double up front on the glass, v blocked the tail on with ca for plastic, I use mini metal gear servos, mini Rx and 270 mah battery, all this to cover the extra weight added with the carbon and glue, I have had several mid airs and never got knocked down I slamed it in to the ground almost full bore with out any airframe damage, ( broke the eng. Mount)My point to this is you can reinfoce things to be almost indestrutable, so I wuld try it again , I buy short kits so I can buy the wood of my likeing, also once you build one the next one is a breeze, or heck build to at once DON'T GIVE UP its to much fun , Fastlash

Predator "Two flights to disaster"
 

Ditto JK,

Had no problems with mine, but the wing isn't as stiff as i would like it to be. i am thinking i would like to use a spar doubler, or get some cap strips over and under the spar, so it acts like an I-beam.

Same thing
 

I had the same thing happen to one of my first Predators. Flying it while on vacation just for fun and did essentially the same thing you did. Took it up to about 300' and put her into a full throttle power dive. About 100' off the deck I seen the wings start to flap and about the time I cut the throttle SNAP the wing broke in two. The key is like the other gentleman said. You'll never see that scenario in combat and if you want to power them up a little you can add a CF rod top/bottom along the center spar to give it some rigidity.

Predator "Two flights to disaster"
 

I am down to one predator now. Last one got chewed up real good by a T Rex in Havoc Over Hamilton. I have found them to be extremely tough with many dirt naps and HARD mid airs. Bi-dirctional tape on the bottom is a must, and I used RSN on both to gaurd against prop cuts, which worked out well. I have flown both into full power dives and pulled up close to the ground with no problem. Balance is extremely critical--build the plane and balance per directions by balancing gear on plane before cutting the foam. It will save lots of heart burn. Both of mine were tail heavy using the supplied drawings.

I have found the Tuff Flight guys to be very understanding and responsive.

Good luck and give the Predator another try.

Greg

Predator "Two flights to disaster"
 

I folded the wing on one of my Predators, but I had to work at it. I was getting ready for NE Nats, a C class event. So I pulled my .25 and put on an OS .32F with a mousse can that I had handy. What a monster that created.

On the first test flight, I did a full power dive, and the wing started flapping like crazy on pullout. I chopped the throttle and landed in the tall grass. I acutally had fairly good control, all things considered.

This predator had been hit from above in a previous contest, so the spar might have been weakened, I'm not sure.

The spar didn't break, it just folded sideways and buckled badly. I mounted my servo's sideways for CG reasons, and clost to the center to make rolls crisper. The spar buckled in to both servo compartments, and the foam tore some though the receiver area.

I think the problem was not having enough foam along the spars in the center of the wing. If I do another predator, I will make sure everything is mounted farther outboard, and farther from the spar where possible, so the spar can't flex front to back. Basically, make sure the spar is well supported on both sides, espeically in the middle.

Oh, and I fixed the Predator in question in two nights, test flew it in the rain the next day, then fought 5 rounds of combat with it that weekend. The fix was epoxing some carbon fiber doublers to the front and back of the spar.

Predator + OS .32 + KY mousse can + APC 10x5 = fast turning rocket ship. One hell of a class C ship.

Here is the predator in question, with the origional .25 engine, before folding the wing.

http://www.wheek.org/airplanes/predatorred4.jpg

Predator "Two flights to disaster"
 

Nice looking Predator Monty. Here is mine (right) after a couple of rough heats.

Predator "Two flights to disaster"
 

Thanks. In the picture you can see the wingtip of my backup predator, it's done the same way, but blue instead of red. I know it's a fairly plain looking scheme, but it shows up really well in the air.

Your predators look like they've seen better days. The term "war weary" comes to mind.

I don't have any pictures of my red predator after the midair or the wing folding, but at a distance it looks the same, it's only up close can you see all the seams in the covering, and the patches covering up the holes that were put in it.

I really love how the predators fly, espeically at slow speeds and high angle of attack. I don't know about other people's but mine always give a little yaw "wiggle" when I yank in too much elevator, giving me a split second to avoid rolling out of loops or turns.