RE: Lancair Wing Failures
 

Steve,
I'm not aware if you knew or not but Sergio's Lancair wing failed this weekend in straight an level flight. He has a Super Tigre .90 on it but I understand that it was new and they were still breaking it in. It broke in half and on the one wing that was relatively intact, it looks like center ribs are not adequately glued to the stucture. Nor is there sufficient contact of the joiner. As Sergio didn't build it, I assumed the original builder failed to put it together properly. I'll have to talk to him and see if he still has the parts to send back to GP.

Now get back to work...... :D,

Mike

RE: Lancair Wing Failures
 

We did notice that. But it has also been noticed that the Lancair wing roots have limited contact area because of a large open area were the two halves come together. There have been a couple of posts were people filled in these areas to further strengthen the wing. It has also come to light that the wing may have not been assembled properly. but an ST .90 exceeds this planes design specs and we all know how Dave flies. I was watching too. [:-]

RE: Lancair Wing Failures
 

Any pics from the NTSB? Sorry to hear about another failure.

RE: Lancair Wing Failures
 

I am planning on having some good airtime on my Lancair this weekend. Hopefully things will stay together in the sky.
Out of a dozen flights I've done only two inside loops. I'm still a little apprehensive when flying this plane.
Instead of GP changing its product perhaps it should adjust it's Lancair Real Flight Simulator model so that when you fly it at full throttle and under some stress - the wing breaks off. That way the pilot can learn to fly the model - without the wing?

RE: Lancair Wing Failures
 

I think I'll park my car farther away and stand behind a barrier when I see a GP lancair in the air.

RE: Lancair Wing Failures
 

Wow! Didn't get a chance to read all the recent posts but it sounds like many are finding the same problems and Solutions.

I posted some comments on the lancair pics post but I'd like to dispel some excuses that are being made for the manufacturer.

1) It concerns me that some are starting to highlight the need to limit flying habits. To quote some "fly scale".

Lets face it, Models will virtually never fly scale but can only really look like they do. Model = Real world, Grass = Corn field, 35+mph wind = hurricane forces, rough landing = landing gear cave in etc.

Models have to be built a little stronger since for the average forces are far higher to the scale. Plus there are always rougher days where we can't always make it look like we are flying scale.

Don't get me wrong this plane is easier than most to over stress with a long thin foil wing span, so care is needed. Further Lancairs are being used in air races and are designed to slip through the air efficiently.

Still even the real ES will take a dive now and then without the expectation of the wings folding.

(See lancair site on ES: Wing Loading: 23 Lbs/Sq. Ft. G Loading: (+4.4 -2.3 G's utility), Cruise: (typical) 225 Mph @ 8,000' (with IO-550))

2) The Engines chosen by many is a manufacturers concern??? the OS.61FX (29oz with muffler) can obtain upper speeds of 90mph+ with a 2 blade 12/11. If the manufacturer allowed that kind of speed, they should not be concerned with most having used the 4strokes and the Master Screw 3 blade 11/7or8 or any props with pitches in this mid range. It would require the operators to put the plane in a dive to get up to those speeds. Even if some built heavy say 10 lbs the wing load would be up to about 33oz/sq ft. If this was too much they have built the plane far too close to its limits.

Even with most solutions brought forward, the wing construction still has some serious concerns.

The Spar often in question barely gets out beyond the fuse. There is too little support just past the fuse for the flexing expected with this wing. On close examination, the constructions details are poorly done. Check your wings down the servo bays and control cable canals for poor quality lumber between the ribs, the lack of glue and or poor jigging.

As I said, "Sounds like GP should offer a wing "kit" of better construction (long CF or Aluminum support shafts) for a very low price if not free for those who have bought their ARF's and haven't crashed yet or start recalling the wings for replacement with a better construction".

I hate havig to send things back to the manufacturer if they are going to give you more of the same and I won't be flying the wings that came in the kit without pulling them apart first and fixing the aforementioned. And this was supposed to have been an ARF.

__________________________________________________ _____________________________________
MAX

RE: RE: Lancair Wing Failures
 

I wonder if we get enough of here on RCU to put together an on line petition, If we can get GP to look into this. We the consumers have more power than one would expect. Strength in numbers. If anyone knows how we can do this, lets give it a try.

RE: RE: Lancair Wing Failures
 

Has anyone considered the possibility of aileron flutter? The recommended aileron servo mounting is not the most secure and aileron flutter on this plane would almost certainly tear the wing off.

Jim

RE: RE: Lancair Wing Failures
 

I disagree about the aileron mounting being insecure. I think that when done according to the instructions, the mounting is extremely secure. Now those who are devising their own mounting techniques, ie. super duper velcro, or double-sided foam tape, etc. would have me concerned. We totally buried our first lancair and the ail servos were still in there rock solid. When I stripped the wreck and pried the servos out of the wing, a ton of balsa sheeting came out with them. I wrap 'em in electrical tape, scuff up the tape with some 120 grit, clean with alcohol, and epoxy. Very, very solid. In fact, I like the epoxy method so much that I used it on my nose steering and throttle servos mounted to the inside walls of the main cabin area. As you may know, I have my RUD and EL servos mounted to a new servo plate in the baggage hatch area. This required an separate nose steering servo (at least for me, as I didn't want a super long control rod running from the baggage hatch area to the front end). The runs from these servos are short enough that pushrod tubes are not even required with the heavy-duty push rods supplied in the kit.

RE: RE: Lancair Wing Failures
 

I agree the servos if mounted per instructions would leave something to be desired.
I have the Lancair and I changed the aileron servo mounting. I installed hardwood blocks and installed the servos on them.

RE: RE: Lancair Wing Failures
 

Maybe we can take the same approached that the FAA uses to investigates:

If we could get better crash details from all who have lost their Lancairs would be helpful.

How is your Lancair Configured:
Engine
Prop
Weight
Method of Wing Servo Install
Modifications to wing joint
Were any wing fracture repairs required?

At the time of failure:
How fast approximately was the plane flying?
What was the maneuvers being performed?
Flight surface configuration (Flaps)?
Were there any odd noises heard?

Post Mortem:
Where does it appear that the wing had failed in flight?
Does there appear to be any construction defects from the wreck?
Are the Aileron, Servo links etc. still in tact?
Does the balsa skin of the wings show signs of fracture?
If so in what direction (root-tip or LE-TE)?
What was the condition of the bulkheads (at the Nylon Bolt and dowel)?

__________________________________________________ ________
MAX

RE: RE: Lancair Wing Failures
 

Odd thing: here’s some more maybe’s

I haven't put my wing together yet because of the problems reported and the fractures to the skin and tip out of the box. Minor in my opinion not enough to bother GP when I originally purchased but they did requiring repair. I’ve since mounted one wing at a time to the fuse and slightly flexed the tip to examine the flex characteristics. Now I say flexed slightly. The nylon bolt blind nut and wedge fractured off from the rear bulk head with little effort. I tried the next wing and though it did not come off entirely it too loosened up as well. In both cases this increased the amount of wobble or movement in the wing.

Naturally the structure is stronger once the wings are joined but I'm wondering with a bit of resonance induced by wing tip rotational flexing, minor amounts of flutter etc. I wondering if this may be the start of the failure?

I mean though we hear wings have failed at the Root, it’s not the epoxy or spar that’s failing but something moving the wing back and forth enough to fracture these????? Where is so much movement coming from? and what gives way first?

__________________________________________________ ____________
Max

RE: RE: Lancair Wing Failures
 

What would really be helpful, is if someone with a decent half of a busted wing could uncover and remove to top wing sheeting and take a few pics.
This way, we can see what's going on inside the wing and figure out the best course of action on reinforcement.
Yeah, yeah, I know...the best "course of action" is for GP to remedy the problem. But, there are those, like myself, who enjoy rippin' stuff apart and bashing to our liking. Besides, people just want to fly theses planes, with confidence, NOW. Not wait for a remedy that's likely not to happen.
Quite frankly, the rest of this plane is such a beautiful piece of work (at least the two that I've had are) that a little extra time spent reinforcing the wings' center section by applying rib doublers, shear webbing, cf spars, etc., is worth it. This added strength could probably support a more "scale" main landing gear also (mounted on The rear edge of the wing and angle forward). The landing gear are the least scale part of this plane, other than the leading edge wing step that occurs on the 1:1.

The main issue is that this is supposed to be fun. It's not fun if you are worried about wing parts fluttering from the sky as fiberglass and dirt say "hello" to each other. But it is fun, and rewarding to rework something til' you've satisfied your mind and fly with the confidence of knowing it is thoroughly capable of handling it.

It appears that wing was designed to just get the job done, and in testing, none of their wings failed. So they did the job. I wonder if they push the wings to failure to determine just how much the wing can take?
Unfortunately, or fortunately, when I had scrap wings from our first Lancairs' crash, the wing destruction discussion was relatively a "freak occurance". Consequently, I didn't strip and reveal what was really going on in there.

Whatchawl think?
Paul

RE: RE: Lancair Wing Failures
 

It looks like some are reading far to deep into this. The planes are made by Humans and to err is human. No 2 are goint to be built alike from the factory. In my experience wth ARF's is reiforce the joints you see that need it and be beary about the ones you dont. If it comes apart in the air then either your flying habits are outflying your airplane and loading in excess of allowable tolerances or, you bought a piece of crap built on a Monday.
An ARF is intended to get the pilot in the air as fast as possible and eliminate the building. If you want it better , build it or rebuild it yourself. I have had questionable construction on ARF,s and took the preventative measure to assure that that assembly of mine cause it to come apart.
If the model companies took the time and lengthst we would go to than ARF's prices would exceed the the industry standards. What you would have is a company that makes really high quality ARF's and cant sell enough to pay the rent because the are to darn expensive.
So in conclusion, follow these steps:

1 Assemble
2 Fly
3 Keep clean
4 Repeat step 2 and 3 for as long as it lasts.

RE: RE: Lancair Wing Failures
 

Your simple 4 steps are not gonna work for someone who put 60 hrs. into the plane BEFORE step 1.
SOMEbody rip a wing open for me ;-).

RE: RE: Lancair Wing Failures
 

One of the guys at our field has a Lancair and flies the snot out of it. He has an OS .91 FS on it and built it according to the instructions. He didn't add anything to strengthen the wing. I've seen him fly it a number of times, and yesterday was with him as he was flying. I told him about the concerns many people have here about wing failures and he was surprised. He said he must of recieved "one of the good ones..."

He then went on to show me a few snap rolls, knife edges, high speed dives and high G turns with it. No problem, the plane handled it all very well. His favorite thing is long sweeping low level turns into final on touch and goes. It looked awesome. He said if he lost the plane, he'd buy another in a heartbeat.

Maybe it's a quality control issue, like others here have said. I for one will be looking inside the wing through the servo mount holes and the open center rib before joining the wings. I may even gravity feed some epoxy inside where I can if it looks like mine had a 4:30pm assembly.

RE: RE: Lancair Wing Failures
 

You seem to be confusing the ES with the Columbia. The ES gear is mounted in the center of the wing and has no angle, and the ES leading edge has no step. Sorry to pick nits, but you're knocking a plane that doesn't deserve it.

Jim

RE: RE: Lancair Wing Failures
 

SDCrashmaster:

I can't send an actual picture but I can give you a quick line drawing of how mine is built:

As I said the skin (balsa) on my wings had a few cracks out of the box. I had to take the monokote off to get to the 6 sizable cracks. While doing so i held it up to my office lamp and recorded how the wings were made incase I wanted to make changesor a rebulid was necessary.

I found on both wings glue was missing in several areas. On the rear spar I can see at least on mine was spliced together right wear the fuse and wing would be seated. And as I said the wedge that mounts or holds the nylon wing bolt came off a little too easy for my liking with very little glue visible. ONce this was free the wing movement increased. Even a well constructed wing mounted loosely may vibrate and fail.

For me to fix this won't be too difficult since my windshield came busted and they sent replacements. It makes very easy to get inside the fuse when I need to.

Hope this helps.


Max

RE: RE: Lancair Wing Failures
 

Sorry everyone That was obviously way too small. I'm working on cleaning up that image:)

MAX

RE: RE: Lancair Wing Failures
 

Having a hard time with enlarging this. jpg Filesize is too large.

Generally I found the biggest concern on my wing is the ply that forms the spar on the 3rd rib in from the root is barely glued to anything at the top. There is a 1/8" gap from the top of the ply to the strap of 1/4 X 1/8 wood that makes up the spar. Its visible from the Flap servo bay and is rectangle rather than tapered to the shape of the wing. The same is true for the next chamber in toward the root with a 1/16th"gap on one side.

This is poor construction as though whoever built it was using scrap ply not cut from an actual plan!!!!! I may end up sending this wing back.

This may not be the case with everyone elses wing construction but if I fly this as is, I could see the wing bolt coming loose as i described and or as the wing was stressed, I could see it failing right at the section of sparthat i mentioned without question.

I'll be filling these gaps with milled fiber & epoxy, glassing the root and even putting lite glass on the wing to where the flap & aileron meet. That should hold it be now the weight???



MAX

RE: RE: Lancair Wing Failures
 

Its really sad to see such a lovely plane with so many wing failures when the box states all the manouevers that the plane can do. I got the plane on impulse, it looked really good but my tummy felt funny when I read all the postings about the wing failure, true that the plane is not a acrobatic 3D plane but still, too many faulires. At least I know now how to fix my wing up, glass it and add on the aluminium bracket for the UC.

RE: RE: Lancair Wing Failures
 

Thanks Max

RE: Lancair Wing Failures
 

Actually I don't want to discourage the intent of this model. If they built these right during production you would have a great plane ;) . The wing seems that it should if constructed correctly, handle basic model flying with the occassional aggressive manuever.

But the production line seems to be doing a poor job that hopefully GP will address for future modelsand with model owners.

Remeber, when these first came out fuses had cracks in them, parts were missing, the wrong parts were placed in the kit etc.
The wing problem is just less visible to everyone, until it crashes that is.

I'll see what GP has to say.

MAX

RE: Lancair Wing Failures
 

Its kinda hard to see but here's the gap I was speaking of that makes up the spar on the two inside ribs beside the Flap bay. Its about an 1/8" gap wider on one side and I can move it meaning the glue didn't set on the inside of the spar.
Glad i saw it now rather than busted wide open.

RE: Lancair Wing Failures
 

Have seen several comments about wing failures on the Lancair ES but have not seen any specifics. Exactly where are the failures occurring? If failure occurs at the wing joiner then a better dihedral brace and fiberglassing the center section would definitely help. However, if failure occurs where the fuselage meets the wing, then wing center section beefing would be of no value. Just looking at the wing, I would have guessed that the weakest area would be slightly outboard of the fuselage; from the corner of the 2”x5” leading edge cut out section to the corner of the flap cut out. This would be outboard of the dihedral brace so beefing that up would not help. I am about to start assembling the Lancair ES and would greatly appreciate learning from the experiences of others. Thanks.