maukaonyx

Has there been a rash of wing failures? This is news to me. I am interested since I have one of these planes, and do love it. Jon

cmptrguy

My Feedback: (19)

Wing Failures? First time I have heard of it. Love mine also had it for 3 years

Cmptrguy

goph

hi i think it was only on some of the early ones. issues with the top wing braking in the center.
ive mine for 1 year now and love it,
how heavy is yours mine came out to 9.3kg thats with 7oogrms of lead in the nose to get it to balance
where did you set your c of g at
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maukaonyx

Mine is at 18 pounds plus 4 oz. It was right at 18 pounds when first flown, and now has an additional 4 oz of lead in the nose for a better CG. I know I am close to the CG in the manual, but can't be sure anymore since I have not finger balanced it with help in a while. When I say better CG, that is just my taste in balancing...I like the plane to fly inverted with a slight down pressure on the stick to stay level. I don't like it to climb in this attitude or the 45 degree upline inverted test either. Jon

rcpollo

My Feedback: (6)

I had mine for 3 years, and on a downline the upper wing split right down the middle. It was clear that very little glue was used to join the wing halves. Even the metal tab that screwed into the cabane slid right out. Nothing holding the two pieces together. Lots of issues with this over on Flying Giants. My suggestion is to just fly the plane in circles. Sooner or later that lack of sufficient glue will bite you.

FBaity

My Feedback: (2)

See FG thread:[TABLE="class: tborder, align: center"]
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[TD="class: navbar, colspan: 3"]Assembly of Aeroworks 50CC Ultimate ARF (Black, Red and Yellow)

For lots of broken top wings information.[/TD]
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You last visited: 01-09-2014 at 05:00 PM Private Messages: Unread 0, Total 131.

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FBaity

My Feedback: (2)

Some wing failure data for FG thread:


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[TD="class: alt1"] CAVEAT EMPTOR. ("let the buyer beware")

I could leave it at that but feel obliged to do a 'tell all' for the benefit of others. At the outset I quite happily say that the Aero Works Ultimate 50 I had for such a short time (around 30 flights) was probably the most enjoyable ownership/flying experience I have had in my short 16 year experience with RC aircraft. As I have said before I suffered the apparent top wing failure mid air which resulted in the almost total destruction of the airframe. I my case, I did not have the warning others have reported with the covering buckling.

While the fuselage was reduced to just so much confetti up to the cockpit area, the wings, apart from breaking apart at the centre, were comparatively undamaged. The right half of the top wing that remained attached to the cabane was a little more worse off. The other 3 halves floated gently to earth. AW have offered me 40% off a new kit but when the estimated $600+ freight to Melbourne Airport, Australia is added the resulting $1000+ cost makes this option untenable. I can get a new kit delivered to my door from an Australian dealer for around $850.

A fellow club member also owned an Ultimate which had had a few flights but not with him in control. After witnessing the demise of my model he completely lost confidence in his. In short, I have purchased that model. He had already separated the lower wing halves, using nothing more that a balsa knife I might add. His initial intention was to insert a carbon spar. He has purchased instead a Great Planes Pitts M-12s which has carbon fibre wing joining spars. As I have said to AW, for the sake of just a few extra dollars (and grams) they have compromised an otherwise great kit.

All this has allowed myself and others to have a close look at the construction of the wings. One of those 'others' is a heavy model inspector for the MAAA, the governing body for model aircraft operations in Australia. By way of explanation, in Australia all models weighing over 9kg must first be inspected before being allowed to fly and must be re-inspected every 3 years (if they last that long). This inspector has said that he will not allow any similar model to fly unless suitable strengthening is carried out on the wings to his satisfaction.

It has to be said that each wing half is in itself quite strong. A determined effort to break one half which was supported between the knees succeeded in only a slight deflection in the region of the servo box. It is our collective opinion that the immediately apparent top wing failure was precipitated by a similar weakness in the lower wing. The basic construction for both wings appears to be identical. The lower wing has the benefit of the added support offered by the attachment points to the fuselage. Those front dowels look rather small for the job required of them. It did concern me that there was so much deflection in the wings when carrying out the recommended balancing operation.

Imagine if you will a piece of softwood, possibly (hopefully) spruce, 13.5mm x 9mm in cross section which extends all of 60mm (2.3in) either side from the center out to the first ribs and tapered to follow the sweep back of the wing. This my friends is the only contiguous joiner between the two wing halves. The top wing does have two short aluminium tubes that do nothing more than secure the cabane lugs. In my case the top joiner snapped clean through at the center. The bottom joiner was in one piece having been torn apart from what little adhesive was used on the left side. The center ribs, made from soft 4mm balsa with the mandatory lightening holes, appear not to be glued themselves, reliance seemingly being placed on a 30mm wide bandage of very light glass fibre and resulting resin seepage to further secure the two halves . The only ply ribs that we can see are either side of the servo boxes. Over engineered? I think not!

Why am I persisting with the model? Because it was such an enjoyable plane to fly. The EME on-board electric starter completed the package although this too had its problems.

What am I doing to resolve the wing issue?

Well the top wing will have a 3 layer glass fiber bandage wrapped around the center section starting with 75mm, then 150mm of 2oz mat and at least a 200m wide 3/4oz mat to finish off. The lower wing, because it was already separated, will have a 12.5mm carbon fibre tube extending out to the servo boxes with 2mm 4 ply rib doublers. These will be themselves doubled at the center and the servo boxes. The same glass fibre bandage arrangement will be applied as for the top wing. The outer struts are being discarded to be replaced with 6mm 10ply birch ply units faced either side with carbon fibre. The construction of the supplied struts is also marginal, both snapped at the bottom on my model. The actual attachment of the struts to the wings appears to be quite strong. Yes, there will be a weight penalty but I do not care if this impedes upon the vertical or 3D performance. It will still be an enjoyable performer but without the built in 'Russian Roulette' factor. I am not into 3D stuff anyway. Too old for that caper.

There have been hundreds, I am told, of these kits sold. The fact that there have been a relatively small number of wing failures reported, I repeat 'reported', seems to me to indicate that the construction is marginal and any variation in construction workmanship in the factory can tilt the odds toward failure. I wonder if the construction of the reported wing replacements is different or is it just that more care is taken with them?

The AW Limited Warranty places full responsibility on the purchaser for 'any and all structural or mechanical failures'. Are we therefore also seen to be responsible for the basic design inadequacies and/or factory construction which are/is completely beyond our control? Are we to blame for buying the kit in the first place?

AW is expecting a new shipment of kits late April/early May. We can hardly expect them to openly say that the wings in this new shipment are stronger. This would be admitting a weakness in the current batch. I do hope that they have made an improvement to what is an otherwise great kit.

In my association with RC aircraft I have had my share of mishaps, some might say more than my share. I can understand a manufacturer's point of view that some of our group are reluctant to take the blame for the loss of an aircraft and try to put it on the manufacturer for a replacement. In most if not all but this last incident I fully accept that my losses have been caused by my own lack of talent or preparation. This is different. The Ultimate was half way through a very lazy reverse cuban eight, second flight for the day, when the wings folded. Completely unexpected. I believe that this is a clear case of basic structural failure in the airframe as supplied and feel that AW should supply a new kit, without any charge. To myself and Frank Baity. At least I was able to salvage the servos and batteries. The DLE55 now has a new crankshaft and bearings. Frank lost the lot.

I can supply photos if necessary. I did so for AW and was told that their tech bod could see no reason for the wing failure. Yes Frank, I know just how you feel.

David
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speedracerntrixie

My Feedback: (29)

The more things change the more they stay the same. When AW first came out with the 42% Extra 260 it too had wing failures. They did however do the right thing and issued a recall. I had received one of those airplanes as partial payment for a build job I did. It had been dead sticked and the gear torn off. I had the replacement wings that had been damaged but I also had the original recalled set. I called Aeroworks and during the conversation I had learned they were " fixing " the wings in house. I asked what was being done and was told to remove the balsa sheeting from the bottom side of the wing exposing the wing socket. The fix was to install shear webbing that tied the spars to the wing socket. I did this and recovered the bottom of the wings. After the airplanes 3rd outting while taking the wings off I noticed the right wing was badly damaged. What happened was the the LE sheeting had split top and bottom just in front of the spar. All the ribs were split forward of the spar. A call to AW to let them know that because I did their recommended fix and the wings still failed IMO they now had some responsibility. Dennis told me to send in pictures and he would talk to Rocco. A week later I was told I was on my own as AW only warranties original purchaser. The end result was that I peeled all the sheeting off the wings bottom. This was quite an easy task as it took just a little heat to make the glue fail. I then repaired all the ribs and added a secon row of vertical grained shear web between the spar and LE. This boxed in every rib bay and made the wing incredibly strong. A final call to AW was placed to let them know my findings and that IMO they still had a possible issue. Information was not received at the level of attention I had hoped. In the end I flew the airplane enough to know it was safe and promptly sold it and resolved to never own another AW product.

FBaity

My Feedback: (2)

Are there any further flying reports?

Frank Baity
Contest Director
Leader Member Admin & Scientific
Turbine Waiver Fixed & Rotary
AMA 38026

jcrider

Is there anymore info about these wing failures? I have one of these planes I bought back in 2011 and am just now getting around to finishing it. When I do the finger tip balance you can see the wings deflect slightly not in the center but about where the first open bay starts. To me this seems normal since I'm supporting 18+ pounds only by the wing tips. It would be nice to hear from an Aeroworks rep before I fly this thing.

FBaity

My Feedback: (2)

As stated previously in this thread I lost a 50cc AW Ultimate due to upper wing failure in flight some time ago. AW eventually discounted a new kit and I built another one with promise from AW that wing design had been "beefed up". After 20 flights or so I noticed evidence of separation of upper wing at center joint of the two wing half's. I removed the center covering on upper wing, covering and fairing structure on lower wing and glassed the exterior of center wing structure like an old pattern plane was built years ago. Since this modification the Ultimate has been rock solid after extensive inside and outside maneuvers. I would not trust the wings without modification.

Aero-Works

Hello jcrider,

We have increased the strength of the wing center section on the latest productions. Because yours is an older model I would recommend reinforcing the center section with fiberglass as FBaity has suggested.

Please give us a call we would be happy to answer any questions you might have.

Thank you,
Rocco
303-371-4222

jcrider

Thanks for the replies guys. Had to order some glass cloth but I'll definitely wrap the center sections of both wings before I fly this baby. Heck, its only been 4 years no need to hurry!!

Aero-Works

Let us know if you have any questions.........

Thanks
Rocco

jcrider

Okay I have glassed both wing center sections and finished the airplane. My concern is it weighs ready to fly 19lb 4oz. This is with all recommended servos, 2 1100ma A123packs on receiver, and a 2200 ma LiIon with a regulator for ignition. It balances pretty close to the recommended CG with the batteries as far forward as I can get them so I'm not sure I can remove any weight up front and the options for removing any significant weight behind the CG are limited. I'm sure it will fly at this weight but that seems awfully heavy. What do you guys think??

daveopam

My Feedback: (9)

I think you will be surprised how well it will fly at that weight. Back in the day I flew many a Goldberg with a Enya 1.20 and smoke that pushed 12 lbs. It was still a joy to fly as long as remembered to land it like a bipe.

David