Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
I had a SIG 4*120 ARF, after a few flights I noticed the wings flapping, and found that the spars were loose inside the wings, and stripped the covering off, squeezed them in position and reglued them all, using CA and Titebond, then recovered them. They appeared to be sturdy with no more flex in them, so today I flew it. Had it up for 15 minutes, gentle turns, no hotdogging, a few loops some rolls mostly half throttle flying, landed, checked the wings and they still appeared to be tight, no flex detected. I put my Kadet up for a test flight after doing the repairs fom when I had a mishap with a strong cross wind that took me by surprise that flipped it on landing and broke it in half. It flew great, but with the Magnum on it instead of the OS as I couldnt find a new motor mount that matched the old one, but the Magnum happened to be a perfect fit. It flies a little quicker with the OS, but the Magnum is still new, so give it some time.
Anyhow, after I was done with the Kadet, and very relieved it still flies well, and lands well, I restarted my 4* and took off, flying around, and had really relaxed with it and was finally comfortable with the plane where I can relax and enjoy it, and about 12 minutes into the flight, doing large loops, some rols, and few stall turns, hammer heads, etc, mostly at half throttle, and about a minute before I was planning to land, the right wing snapped off, I had just pulled up to start a loop when it went Craks, and I saw it flutter off, and the plane start its death spiral. It was done for I had no control over it, so I killed the ignition and spotted where it went into the corn field. I packed everything up and went searching. I am definately getting lost plane alarms for my planes, what a PITA. I eventually found it right about where I thought it would be, but have not found the right wing, got dark so will go looking for it tomorrow, and hopefully get it before tehy harvest the corn and hope the servo is still good. The one in the left wing appears to have been stripped, so verdict still out on that, but the rest of the gear looks OK, the ignition module got lost somewhere on the walk back through the corn field. The only part still in OK shape is the tail, but its pretty much a lost cause.
This will be my last ARF, after this I just dont trust something that I didn't build. My Kadet has been thrown around the sky much harder than I did the 4*, and has been smacked into things a few times, and not once did I ever have to worry if the wing would snap off. The construction on the ARF is not very good, the spar does not go all the way to the center, but ends at a plywood box that the aluminum joiner slides into. It looks like that is exactly where the wing snapped off. I wont know for sure until I find the wing. Now heres the weird thing, the wing that had the most cracks in it and needed the most repairs was not the wing that snapped off. The broken one just needed some reglueing at all the joints, and looked like it was fine.
I really liked flying the 4*, but after this I dont know if I will build another one, or something else, but it wont be an ARF, it will be one I build that I know wont break apart under mild aerobatics. It had a couple minor dings hitting corn stalks, once on take off and once on landing, but at very slow speeds, the first one cracked the leading edge at the last rib, the second one knocked the tail wheel off, but the wing was fine. Neither of those should have caused any damage to the spars, at least they would not have done so on my Kadet, but in any case, I am not too thrilled with this.
Posts: 638
Score: 115 Joined: 1/6/2008 Last Login: 2/26/2013 From: Birmingham, AL, USA Status: offline
Okay, thanks for the warning. Sorry to hear of your bad fortune.
Here's what I did to my ARF Telemaster.
Fuselage: I taped a cheap epoxy brush to a length of coat hanger wire. I mixed up a batch of thinned slow epoxy, 1 part each of A, B and rubbing alcohol. I then peered into the tail and painted each area where a former met a side.When I got out of the tail, the painting of formers was, of course, easier. Then I put some full strength epoxy to reinforce the firewall and LG area. I went over the stab and tail joint dripping some thin CA into the crack.
For the wings, I got some diabetic syringes from my used box. I poked in a tiny hole at each joint of main spar and rib and put in about .10 cc thin epoxy. When I went over with a medium hot iron, most of the holes disappeared.
Just not sure how well it was glued before because I discovered some glops of hot glue gun stuff inside the fuselage. But an hour of so of my time and a little bit of weight has increased my confidence a lot. I have found some thick clear tape to join the wing halves for strength and I will use the spars.
So hopefully it will fly without shucking off a piece.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
If you notice the silver covering, that was where I removed the covering and opened up the wing to repair the main spars, and did it to both wings, Thought I had nipped it in the bud, and solved the problem, but I guess not. I really enjoyed flying that beast too. I had done pretty much the same thing you did, reglued everything I could see and reach, so the fuse was strong, but there was only so much I could do with the wing.
Posts: 805
Score: 219 Joined: 1/18/2012 Last Login: 5/21/2013 From: Grand Prairie,
TX, USA Status: offline
This isn't the first time I've seen this happen. But what can you do? It would be nice if they , the manufacturer, would just put the parts in a box and let us build them.
I get so tired of going to the field and most everyone has planes that all look alike.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
I did some examination of the wing and found the cause of the failure. The main spars are attached to the center rib, and rib #4, in between C and 4 are two plywood sides that ribs 2 & 3 attach to, Neither of them were glued to the main spars. The plywood and spars make a box for the aluminum joiner bar to slip into and I can see where the joiner was pressing against the top and bottom spars and pushed them away from the ribs. There is NO glue whatsoever on either of the plywood pieces where it met the spars, so this is clearly a manufacturing issue, and a major weak spot in the wings, especially a plane that is designed to be a sport plane where wing strength is critical.
Going to contact SIG on this and see what they will do about it. I don't want another ARF, that's for sure, but a replacement kit would be acceptable. It wont pay for the damaged servo and engine, but it would replace the destroyed plane.
Posts: 961
Score: 159 Joined: 6/28/2008 Last Login: 5/21/2013 From: Westerly,
RI, USA Status: online
A guy at my field was flying a 4* 60 ARF a couple weeks ago, same thing. It was brand new and he was just flying around at normal speeds, pulled out of a shallow dive and snapped the wing in half. Looking at it afterwards it was clearly a manufacturing defect. I might not remember 100% correctly, but I think the joiner that he epoxied in between the wing halves was still strongly glued to the plywood box, so he did his job. The plywood box inside the wing let go, that was Sig's fault.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
I have been contemplating picking up a 4*40 ARF that the LHS still has one each or, red and yellow, but after this incident, totally glad I passed it up. I sent the email to Sig, and was very cordial, and explained the whole thing, along with the above photos and asked that they replace the ARF with the same plane in a kt with the covering. It seems like a fair enough deal to me considering it clearly states in the manual on page 19,
quote:
SIG MFG. CO's obligation shall be to replace those parts of the kit proven to be defective or missing
Since this is clearly the result of a defect, they are obligated to replace the plane. Also considering that the defect is internal to the wing and not something that can be seen, they have no recourse on this to lay the blame on me as if I should have known and not flown the plane.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
Two thumbs up for SIG, they came through and will replace it with a kit and covering. I just have to dig up the receipt for it.
Please note I have nothing bad to say about SIG, or the 4*, just an FYI if you have one of these ARF's CHECK YOUR WINGS! I am done buying ARF's though after this, if I dont build it, I cant trust it.
I was looking at the Sig website a while back, didn't see many kits on it. I have a 4*star 120 kit that I bought probably 18 years ago, started to build it, then ended up moving and and quit flying for 14 years. I recently started working on it again as I took up flying once more. Used koverall on it and just in the process of painting it with dope. I have an OS 120 surpass pumped engine that I bought in 1994 and is still in the box to power it. Should be ready to go in a month or so.
Posts: 1191
Score: 178 Joined: 12/26/2005 Last Login: 5/21/2013 From: kempton,
PA, USA Status: offline
Kudos for SIG for standing up to their issue. Unfortunate that they have had to resort to paying Chinese to build arfs so they can survive. I wonder why they don't use CA instead of hot glue on these things, afterall they make that too.
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Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
They should have used SOME glue, whether hot melt or CA, but chose not to use ANY glue for the box, and that is why it failed. There were two things they could have done to make the box solid, and that would be to make the plywood piece go all the way to the top and bottom of the spars and glued them in place, and there would have not been any failures. Instead the plywood comes up to the bottom of the top spar and top of the bottom spar, doesn't touch them and no glue joint to secure them. This is most likely the reason the kits were discontinued in the first place.
Here is what I find interesting, the ARF is not built the same as the kit, so who made the ARF parts? Are they based loosely on the design of the SIG kit? Does SIG make the parts?
Posts: 59
Score: 101 Joined: 8/15/2011 Last Login: 5/21/2013 From: Dubuque, IA, USA Status: offline
I will never understand why a lot of ARFs are built using hot glue when CA dries just as fast anyway. It must be a cost thing.
Acdii. I built a four * kit 16 years ago and it still flies today. The advantage of this plane is that it builds very quickly. (probably as quickly as some arfs) Good to see a company do the right thing too.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
Of all the receipts I have, you would think I could find this one, but NOOOO, I found all the other receipts for the rest of the parts I bought for this plane, but not the one I need. I also know which day I bought it and what I paid, but cant find the damned receipt. Going to give the hobbyshop a call tomorrow and see if they can print up another receipt, I have the info on my credit card statement.
Posts: 1961
Score: 153 Joined: 9/7/2006 Last Login: 5/21/2013 From: White Oak,
TX, USA Status: offline
I recently assembled my second Ultra Stick Lite and contemplated following what another had done with his Ultra Stick making it a two piece wing by not gluing the spar joiner. After some thought, it occurred to me the pressure that would be pushing the spars away from the ribs and that force had to rely on the plywood box holding the spars from spreading. I opted not to do it... and glued the spar joiner in to make the wing a one piece, with the result that the spar joiner is now integral to the spars rather than allowed to be a force pushing the spars apart.
One option for 4* builds then would be to glue a hardwood joiner in and make the wing one piece if such is manageable for transportation. I think doing so would strengthen the wing considerably.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
Well, if the plywood they used for the box actually extended to the top and bottom of hte wing and was actually glued to the spars, then it would be a non issue. I found the wing that broke off last night and discovered that not only was the plywood not glued to the spars, the spars were not glued to each other. The spars consist of two long pieces on both the top and bottom, and I can see no glue at all between the two pieces. I can also see that the wing snapped right off at the fuse, spars and all, and since there were no pieces of spar at the crash site, proves that the spars weren't glued in well at all to the center fuse nor the plywood sheeting. Funny thing is, aside from ribs 4 & 5 being cracked, the rest of the wing is fully intact.
Posts: 1627
Score: 185 Joined: 2/22/2007 Last Login: 5/21/2013 From: Dearborn,
MI, USA Status: offline
Sorry about your loss. I know Sig is a good company. 5 years ago I crashed my 4*40 ARF into a tree and broke the wing at the root. I had epoxied the joiner and filled the box with epoxy. The center section was so strong, that I had to saw off the 2 inner rib bays and rebuild the wing a bit shorter because the spars broke off where the joiner box ended.
I think companies like SIG contract out the ARFs to be made overseas with some oversight. But I think that is where a company contracting out the ARFs should have very tight control of the manufacturing process to ensure good quality control. In my case, the ARF was very well built, but in your case, not. That is a quality control issue. It may be that your ARF was made during the time they were having issues between SIG and the manufacturer.
I had called Sig to see if they had ARF wings available, but they didn't. I ordered the kit wing plans and then realized that the kit wing is different than the ARF. So, I think you're right, the original kit design is not the same as the copied ARF design. Factories re-design the plane to make it easier to manufacture.
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Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
Definitely! I looked at the wing I retrieved, it lost almost all the top covering when it came off and I can see how it was built. The pieces are all laser cut, and snap together, then they use a glue gun to glue it all up. Very little glue is used on them. The webs have no fillets of glue, looks like they were stuck in after some glue was applied. The Shear webs would have helped keep the wing spars together had they been glued in correctly, heck that all the wing needed was to be glued correctly. Except for the fuse being totally smashed up to the cockpit, the plane may be rebuildable. The wings are, thats for sure, 90% of the ribs are intact. Looks like if I were to strip the covering, I could replace the spars, and a few broken stringers, rebuild the box correctly, and replace the few broken ribs, and make the wing one piece. The fuse needs to be totally rebuilt from behind the cockpit though, and not much is recognizable for use as a template. The tail however is totally intact and in perfect condition.
Posts: 1627
Score: 185 Joined: 2/22/2007 Last Login: 5/21/2013 From: Dearborn,
MI, USA Status: offline
Even though the kit implementation is different than the ARF, you could buy the kit plans from SIG and rebuild the fuse. Heck, if you get re-imbursed with a kit from SIG, you can use the plans from the kit and re-build your ARF fuse as well. You will end up with 2 4*'s, double the fun!!!
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Posts: 1329
Score: 118 Joined: 7/25/2002 Last Login: 5/21/2013 From: Barstow,
CA, USA Status: offline
I stopped building from kits when the quality of the material provided became unuseable. ARFs from China are not perfect but they allowed the average modeler to enjoy areas of this hobby that were not obtainable. I'm refering too scale models of various sizes and interest. Your experience is not the first and will not be the last however the only thing that will detere the modeler from buying an ARF will be the price.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
quote:
ORIGINAL: hsukaria
Even though the kit implementation is different than the ARF, you could buy the kit plans from SIG and rebuild the fuse. Heck, if you get re-imbursed with a kit from SIG, you can use the plans from the kit and re-build your ARF fuse as well. You will end up with 2 4*'s, double the fun!!!
That is EXACTLY what I plan to do!
BTW, any one have issues posting after using caps? What I typed exactly in caps, my cursor jumped to the beginning of the sentence, and when I moved it to the end, all text disappeared, then reappeared with my cursor back at the beginning. Happened a couple times now.
Posts: 2293
Score: 155 Joined: 1/31/2011 Last Login: 5/20/2013 From: Capron,
IL, USA Status: offline
The problem is, with the influx of ARF, many of the kits have disappeared, making it difficult for us kit builders to find anything anymore to build, so we have to then resort to plan builds, which not many of us have means to do where you need certain tools to cut the parts out with, or room to use them. Thankfully I have a large workshop and bandsaw, and other tools from my wood working days, but not everyone has that luxury.
Just remember, you get what you pay for, most of the time.
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Score: 100 Joined: 1/10/2004 Last Login: 5/15/2013 From: Jonesboro,
AR, USA Status: offline
I certainly understand the frustration ACDii has with ARFs and I sympathize with him and those who have had similiar ARF airframe failures. Sometimes there is just not the access to all parts of an airframe for inspection without stripping it down, inspecting it, fixing it, and then recovering it. That's not cost effective and should not be necessary. I am reluctant to buy an expensive ARF only to have it come apart at the stress points.
Are there ARF flyers who are satisfied with the sturdyness, longevity, and confidence in the ARF products they buy? It would be interesting to see how many flyers are content with their purchase, quality of airframe, and flight performance of ARFs. Perhaps it is just a few importers who sell inferior ARFs.
Posts: 1627
Score: 185 Joined: 2/22/2007 Last Login: 5/21/2013 From: Dearborn,
MI, USA Status: offline
I have several ARF's that I am totally satisfied (and happy) with. Only one ARF was structurally weak, it typically sells for $100 and I got it for $50 new. So, I guess I had to expect some compromises for that price.
After reading about ARF tragedies, I think a good compromise is ARC's. The structure is exposed for the modeler to goop all the glue he wants and then cover it to his liking. There are very few ARC's though.
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Posts: 3879
Score: 177 Joined: 3/9/2005 Last Login: 5/21/2013 From: ankeny,
IA, USA Status: offline
acdii , don't give up on arfs just be aware of the issues.. It sounds like you are now.. the first thing I do when I get an arf is look inside every servo mounting hole, the ends of the wings etc. than I take a long thin paint brush.. often I will tape a dowel onto the wood handle. next drip some white glue, or gorilla glue down into dry joints, paint it into the seams with the brush. it can be a pain. but many arfs allow you to get at a lot of the internal structure this way.. I do the same thing inside the fuse.. with special attention to the back of the firewall, and the landing hard mount areas.
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