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Graupner Terry

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Old 04-01-2003, 12:31 AM
  #1
Chachi639
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Default Graupner Terry

Okay, so maybe it's my own fault.

I bought a Graupner Terry weekend before last, and spent a few hours over the weeknights last week doing the little bit of work it takes to fit it out. I had a 7.2V Speed 400 motor left over from a previous project, and a 8.4V battery. When I got done, the all up weight was 490 grams and the plane was nose heavy, probably because the design expects a 6 cell battery and mine was 7 cells. I added weight to the tail, and came up with a balanced plane that weighed a little less than the 520 grams that is listed on the box.

I thought, okay, that's fine.

I went out to fly on Friday. It was a little windy but I figured I'd go easy and everything would be fine. I launched it and it climbed fine, I took a turn downwind and came back around and decided to land because the conditions were a little too peppy for me. I got it on the ground just fine, and decided to pack it up for the day.

But then the little devil on my shoulder said, "what's the fun in that?"

I think you know what happens next, but maybe it's not exactly what you'd expect.

I launched it again, and climbed to about 100 feet of altitude. Then I figured, well, the reviews say this baby loops easily, let's give it a try.

My first attempt I hadn't enough airspeed and the model stalled in a completely vertical nose-up attitude. The plane flopped back to a nose down attitude and there was no problem with the recovery. I climbed a little more to gain some room for error, and tried again but this time with more of a dive.

Well, maybe too much of a dive. I ended up basically in a vertical dive, and said, "whoops, better pull up!" I pulled full up elevator, and the wings promptly folded. Half of the wing joined the fuselage in its imitation of a lawn dart, and the other fluttered downwind. I chased down the wing half that was flying away in the hopes that I'd be able to patch things back together, but as you can imagine, a 30mph vertical impact isn't good for any airframe, even "durable" foam. The plane is a total loss, and my speed 400 motor is gone as well. At least the rest of my radio is okay.

Has anyone else had a problem with the durability of the wing on the Terry? Given that I'm seeing other posts here (too late for me) showing strapping tape under the wing, I'm thinking maybe so?

Remember, now, that the model was within it's spec weight. Also, the elevator control throws were not excessive: we're talking less than +/- 3mm. Am I being unreasonable in expecting that I wouldn't fold the wings on the first flight?

Hal
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Old 04-01-2003, 12:45 AM
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flyinrog
 
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Default Graupner Terry

happened to me with a GWS plane,not on the first flight but I was about 200 feet up and diving for a loop (apparently one of the more stressful manuvers) and the wing folded and it came down hard ruining the wing and motor too...so foam planes arent made for aerobatics, well not diving for loops anyway..Rog
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Old 04-01-2003, 06:35 AM
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Default Graupner Terry

A plane without a spar to take the tension and compression loads is bound to fail.

--Paul
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Old 04-01-2003, 04:51 PM
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Default Graupner Terry

I have pulled a similar stunt with my foam Piper - yes, I can hear the wing groan under the strain, although I haven't outright snapped one in half yet (well, not while doing a loop anyway :^)

I'm using a different battery, too. I borrowed a six-pack out of a Firebird XL, when I think the plane was built for a four-cell.

Do you still have the Terry? You might make a go of salvaging it. I was absolutely amazed when I brought the Piper home looking like styrofoam packing peanuts one day, but with a little care and puzzle work (lots of plain white glue, too) it went back together almost as good as new. You're right - foam planes can be less than "fully aerobatic"!

If you can get a working motor, you might as well give it a try. What have you got to lose?

Dan.
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Old 04-01-2003, 11:02 PM
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Default graupner terry

it happened to me second time up also doing a loop. just glued pieces back together with 5 minute epoxy and then put piece of strapping tape on the bottom of wing with a little tension and worked great. this plane is a great fun plane i learned to fly with it was glued together so many times the fuselog looked like a cork screw and probably weighed twice as much as when i started , just from all the glue, i even used chunks of styrofoam cooler to fill in the gaps when i couldn't find the pieces. after i finally learned to fly somewhat i ordered a new fuse and i still fly it even though i've got other planes now, but i'm still using the original wing, WHAT FUN IT IS!!!!!
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Old 04-02-2003, 12:36 AM
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Default Graupner Terry

yeah I fixed my first one with ca and strips I cut off a 2L cola bottle, so after the umteenth crash it was looking pretty tired and motor was going too, so I just got another one (stick FD)..Rog
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Old 04-02-2003, 04:24 PM
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Matt Kirsch
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Default Graupner Terry

It certainly doesn't sound like a manufacturing defect. That plane is not designed to withstand high-G maneuvers, such as abrupt pull-outs from full-power vertical dives. You might've stood a chance if you cut power and tried to ease the plane back to level.
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Old 04-03-2003, 07:54 PM
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Default Graupner Terry

I've got a Terry which does not have a spar implanted in the wing or even packing tape, but I did cover it in low temp Black Baron film. Do you guys think that the film will help, or should I maybe implant a spar? I have not flown yet due to the weather here in Canada. Hobby Lobby shows movie clips of the Terry doing inside and outside loops, so I assumed that it would be structurally sound as designed.
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Old 04-04-2003, 01:35 AM
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Chachi639
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Default Graupner Terry

As did I, for the same reasons. I guess that I've been tought an $80 lesson otherwise (the Terry plus the motor cost).
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Old 04-09-2003, 09:29 PM
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Default motor cost to high?

Hey, those motors are only 5 bucks on ebay all the time. I bought two brand new ones that had "zagi" stickers on 'em for 8 bucks plus shipping. Just search for "speed 400" and you will get a complete list of dozens of 'em.
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Old 04-09-2003, 11:06 PM
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Default Old School Balsa Flyers Rule!

Hey Hal,

I'm sorry about your folding wing problem - I blame it on the "make 'em cheap, make 'em poorly, make 'em out of foam" syndrome. It should not happen, but unfortunately too many of the manufacturers these days don't care about a quality product -it is clear that far too many "ARF R/C trainer aircraft" are too heavy and/or way-underpowered and too delicate for their intended purpose - I begin to doubt whether they ever test fly any of them! I must say that I am surprised that your "catastrophic failure" occurred with a Graupner product because I have always had respect for their craftsmanship and I've seen very good reviews of the Terry!

As an old C/L diesel (Oliver Tiger 2.5cc) combat flyer from years ago - we used to make our planes from balsa with nylon covering - they would fly at 90mph and pile into the ground at the same speed, without any damage - even the props didn't break (I actually still have a couple of, admittedly worn and bent, 8x8 nylon props from 1963 which I've used as test-bench props on my PAW .19, and a year or so ago I made a C/L combat wing "Unlimited" from a plan I'd kept from that era)! It is a different world now and flimsy ARF's are in vogue - obviously, though, electric R/C planes could never be as bullet proof as our flying bricks - so there has to some compromise!

If you get upset with foam products, why don't you build a "real" plane - balsa and carbon fiber tube spars, and Solite covering - you'll have a strong, light machine which can readily be repaired even if (when) you crash it!

Well, that's off my chest!

Cheers, Phil
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Old 04-16-2003, 07:59 PM
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Default Graupner Terry

I too have had a less than happy experience with my new Terry, I am an experienced flier who after a layoff of 10 years decided to get something simple to get reacquainted and see if I could still twiddle the sticks. It was it's first session and I had 5 good flights, steady climb outs, two BIG loops(power off) and just cruising around then I did a high speed straight and level pass pulled back stick in to another climb for altitude and the wing folded. I was totally gutted, surprised and disappointed. I am still of the opinion that I did nothing wrong and it is inherently weak. I read all the reviews, watched the video of it doing an inside loop and felt that for all it was foam it was at least able to take some knocks. On close inspection the foam core where it broke is not as dense as I feel it should be (air holes) and feel it is possibly a duff wing, anyway it's epoxied together, have to get a new motor and prop then we will have another go. My advice is treat it as it looks..........delicately........
Jon
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Old 04-16-2003, 10:40 PM
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Default here's what I did

O.K. so I'm no expert but I read what happened to the other guy's wing and I decided to "implant" a spar in the bottom of my Terry wing. I used a wooden dowel that was a bit thinner than a pencil and cut a slot in the bottom of the wing. Then I cut the dowel in the center half way through, and bent it to fit the angle of the wing. Then I glued it in the slot and sanded the whole issue flat. The spar stops about 4 inches from the wing tip on each side. I have only flown it three times - so far so good, I got loops, big and small, and pulled out of a moderate dive with no trouble. I have my fingers crossed.....
zilla
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Old 05-02-2003, 10:41 PM
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Default Re: motor cost to high?

Quote:
Originally posted by Chachi639
As did I, for the same reasons. I guess that I've been tought an $80 lesson otherwise (the Terry plus the motor cost).
Quote:
Originally posted by dadzilla-5
Hey, those motors are only 5 bucks on ebay all the time. I bought two brand new ones that had "zagi" stickers on 'em for 8 bucks plus shipping. Just search for "speed 400" and you will get a complete list of dozens of 'em.
I don't know which ebay you're looking on, but from what I'm seeing, by the time you put a speed 400 together with a folding prop, you're at about 14 or 15 bucks. Shipping puts it at 18 total. My cost for the Terry was 62 bucks including tax.

I'm out $80, why try to sugar-coat it?
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Old 05-03-2003, 01:59 AM
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Default Graupner Terry

You even toasted the prop? I meant the ebay at *********....you know a different one? There are 5 dollar speed 400 engines there all the time. But hey, I agree it hurts to lose an airplane, and it doesn't seem right that the wing would fold up on you like that. What are you gonna build next?
zilla
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