mydartswinger

Hello all,
Last week while flying the newest addition to my hangar, a Carl Goldberg Decathlon, the left side wing strut fell off in flight. I didn't notice that it was gone until I landed and went to put her in the car to go home. I checked the runway and pit areas to make sure that it didn't fall off there, but apparently it fell off while flying over the soy bean field. Does anyone know if it's OK to fly this airplane without the wing struts? The seem to be made of a light wood (not balsa or light ply) and bend fairly easy. They're only held on by clevises at the wing and a linkage rod with a "z" bend at the fuselage. To me, they don't seem to provide anything more than looks, but I may be wrong. This airplane is a joy to fly and I want to put her back in the air soon. Any insight as to wether or not the wing struts on this plane provide any structural support, and if it can be flown without them would be greatly appreciated. Thanks in advance.

Attached is a picture of the plane in question before the wing strut fell off.

Ugo Ferrari

My Feedback: (1)

I'll stick my neck out here... The struts in this case are just eye wash ! I flew my Decathlon without them (til I sold it). They were just a PITA and surved no purpose ! The wing is built like a truck anyway...Please don't fold the wings now LOL !
Ugo

mydartswinger

Thank you, Ferrari. As flimsy as they are, I figured they were just eye candy, just wanted to confirm. I knew they were trouble when I first laid eyes on them (the wing struts). I don't particularly care for the clevis attachment, I would prefer screws. I know screws would be a bit more of a PITA to assemble/disassemble the plane at the field, but would be more comfort knowing that as long as the screws are tight, the struts won't fall off in flight.

Thanks again and happy flying.

sodbuster 1

Don't be fooled.They're definitely structural. At least if you're doing any kind of aerobatics.....
It's an 80" thin airfoiled wing with only the two dowels and two wing attachment screws.Plus the wing is attached to a high not very stiff fuselage with a lot of open space due to the large windows.
I blew one off on my second flight while doing a snap roll.Just the fact that enough stress caused it to blow off told me they're structural. The reason it blew off is like you said, they are a little flimsy so I beefed mine up.
The first problem with them is the clevises they use.They're not made from spring steel they're made from stamped steel so they snap very easily.Replace them with better quality black colored Dubro's. They're made from spring steel.
Second thing is the way they secured the 2-56 rod to the strut itself. I noticed after the 3rd flight that one of the rods was seperating from the strut and also because the Chinacote covering looked so crappy I decided to strip the covering and fix the rods.
Glad I did. The struts are grooved on the outside surface in which the rods sit and are just epoxied in. The end of the rod has a 90 degree bend that goes thru a hole in the strut, but that's it. Once the epoxy seperates a little the rods peel away from the wood.
What I did to fix this was take fishing line and wrap it around the strut at either end of the rod and then thick CA'd the two ends all along the fishing line.
Instead of recovering the struts which seemed like mission impossible because of the compound curves where the two pieces of wood come together, I painted them white.
I took some clear dope mixed a little talcum powder in with it to act as grain filler applied two coats and gave a light scuff sanding afterwards to smooth it and then shot it with white spray from a can.
Then wrapped the the fishing line ends with some white electrical tape.

The whole thing took me about two hours .
That was about 30 flights ago. Haven't had a problem since and let me tell you, I bat that plane around the sky as if it were a 3D machine with a Saito 1.00 in it.

The other reason I know they're structural? I mounted a Flycam inside the fuselage for the funof it and in watching the flight when I got home everytime I did any kind of aerobatic maneuver I could see a gap opening between the top of the fuse and the wing and daylight showing thru till I came out of the maneuver.

Take it for what it's worth

mydartswinger

Ouch... The wings look beefier than my other planes, but if they're not, they're not and need some attention. Looks like I'll be placing a set of struts on order this week and beef them up before I put them on. I had every intent on ordering a new set, I was mainly asking the question to find out if she's still flyable in the meantime...Guess not. Oh, well. If my LHS can get them this week, I can get the those good DuBro clevises to beef them up, and she'll be back in the air next weekend (I won't be flying again until then anyway, was hoping to get an answer within a couple of hours of posting and I might have waited on the struts if they were aesthetic only, but made do without the Decathlon and took my Tiger Moth instead [size thing, not capabilities thing] ). Then I can get to figuring out my engine problem (looks like tuning and/or cooling [OS .91FX], but is going to take a few flights to figure out, as it runs great on the ground and for the first 3-5 minutes of the flight, then dies mid-flight on me).

Thanks for the input.

sodbuster 1

please get back to me if you're able to get parts. I need a set of landing gear badly.

As far as I'm able to tell parts aren't available as the plane's been discontinued.
Least that's what it shows on Towers and Goldbergs site

isaygen

For my Decathlon I need main landing gear and cowling , I install Magnum 160 twin

mydartswinger

After searching the web, it looks like parts are no longer available despite the fact that most CG retailers still have this plane in stock NIB. Goldberg's site shows part numbers and costs for the struts as well as other items, but they don't sell directly to the public. Their site shows part #6189 for $35.95. I'll talk to my LHS's to see if they can get them, if not, I may have to make my own. We'll see how it works out in the end. If worse comes to worse, I might have to order an ARF for parts if I can't order or make what I need.

sodbuster 1

just got off the phone with Great Planes who now owns Goldberg.
No good on parts.

Landing gear are available from TNT $38 NOT made out of cheap Chinese aluminum just ordered a set

http://www.tntlandinggear.com/

call and talk to Kathy. Even though they're not listed on the site, they can make them in one to two days.

mydartswinger

Well, I guess if one of my two LHS's doesn't already have a set in stock, I'll have to make them. Doesn't look to difficult. Just have to select the right wood for the job, measure and cut just right, epoxy, cover, and install the mounts. When I had both, I did check to see if they were the same, and apparently they are. With that being said, I should be able to make a template off of the one that I do have.

Ugo Ferrari

My Feedback: (1)

Like I said...Just a BIG PITA ! LOL !
Ugo

mydartswinger

LOL

mydartswinger

Well, just finished making a new wing strut for her. It's not quite as strong as the original. It seems like the original was made out of bass wood, while I made my new one out of light ply. Not the prettiest workmanship, but it will suffice for using it. It was my first time using iron on covering, so that's what isn't quite so pretty. I used the DuBro 4-40 black metal clevises and a clipped off piece of the rod for the bottom "Z" - bend. I also replaced the stock plastic clevises on the other strut with the same DuBro clevises. I don't want to lose another strut unless I end up crashing the plane, which I don't plan on doing until her final expiration date (which we all know all RC airplanes have one).

Next step, charge, take to the field, and figure out the problem with the engine cutting out as mentioned above. After that's done, enjoy the crap out of this beautiful, great flying airplane.

sodbuster 1

don't feel too bad about the covering job on the strut.like I said in the earlier post, it's a difficult part to cover and have come out looking good even if you're a pro.

good luck with the plane, it's my favorite from my hangar.....flys incredibly scale and will do anything pretty much aerobatically.

mydartswinger

Got a few updates to this issue.

I've got about 10 or so more flights on her. After repairing the wing strut, I made a couple of flights to try and figure out the engine tuning. Danged if the "z" bend at the bottom of the strut came out. Luckily, a club member spotted it and I was able to bring her down without losing it. Popped it back in place, tightened down the clevises, and took her up again. Then back and forth as such for a few flights, then it happened. A couple of other pilots were already on the field picking up another airplane, then the engine died on me with them on the field [:@]. In the heat of the moment, having never been in that particular situation, I decided I would cut the approach short to about halfway down the downwind to turn base. When turning for final, I turned her a bit to sharp about 3 or so feet of the ground. She tip stalled and hit the ground hard. Damage, ripped the wing strut screws right out of the wing on the right side, ripped the Ultracote on the left wingtip, busted the joints on the tip of the left wing, and bent the right landing gear (beefier than stock). The landing gear and the wingtip were no problem to fix. However, the wing strut screws were another story. When the screws ripped out, they took some of the wood with them. To repair the job, I rushed a bit of Sig's Epoxolite to fill the hole. The next time she was out, the screws came right out of the fix. I filled it back up with Epoxolite after putting some thin CA over the site, then allowed the filler to dry for about 2 weeks before messing with it again. I then added some thin CA on the top of the filler and drilled 2 small pilot holes for the screws. I took her to the field yesterday and had no problems with that side. However, I was flying the snot out of it (hovering [first successful hover outside of a simulator ], stall turns, loops, immelmans, split s's, knife edge, brief inverted flight, etc...) and the screws ripped out of the other side [:@]. I'll use the same technique with the filler that I used on the other side to get it to hold (except for the wait 2 weeks part), and tighten up the clevises the best I can to get them stiff.

As sodbuster said, this is also my favorite plane in my hangar. I thoroughly enjoy every flight with her, even the deadsticks as they are so graceful with this plane. She also handles the wind exceptionally well for the way she gets blown around on the ground. She's not difficult to transport in my little Ford Focus, and I still have room for 1-2 .40-.60 size airplanes left over (or my GP Tiger Moth, albeit very tightly with it's 2x's 71" one piece wings), as well as for 2 folding chairs and all of my field equipment. I'm determined to get these wing struts secure, then she should be good to go.

Happy flying.

EDIT:
Just figured I'd show a quick pic of her in flight on the 1st of November.

sodbuster 1

I like my Decath so much I'm trying to hunt down a 1/3 scale version of it.
Hopefully someeone's built one and wants to sell it lol.
Have a few big gas motors that would fit nicely in one.

Hey Dartswinger probably the next thing that will let go on you is the nylon control horns used to attach the struts to the wing. I changed them out with some Hangar 9 metal ones after the nylon ones tore their holes out. I'm telling you though, over the winter re-do your struts the way I told you. They'll last forever then.

By the way, ALL Decathlons will tip stall at low speeds.The trick is to not make any sharp turns on your landing especially at really low speed. Same thing applies to takeoff. Make sure you have enough speed to not tip stall on takeoff.
On mine I have the ailerons set up to also act as flaps so I do my approachs with speed so as not to tip stall. Fly it right down to a foot off the field and chop your throttle once your flying nice and level across the field and have enough room for the plane to burn off the speed once on the ground.
Deadsticks don't always give you that luxury.The trick with deadsticks is to not panic and rush to get the plane down fast.That most always ends disasterously! Look around the field,know which way the wind is blowing head into it. PLAN your landing.Don't be a victim of it.