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GP Lancair wing failure

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GP Lancair wing failure

Old 12-24-2004, 12:13 AM
  #51  
Sawtooth
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Default RE: GP Lancair wing failure

YIKES!!! I have a Lancair coming!!!! Glad I happened on this this post. I was planning on putting an OS 61 as GP suggests. One post said its under powered with that combination. Maybe thats good for me. I'm still pretty new. This would be my third plane. I've fly a small Extra (.46) to do some aerobatics. Which isn't much. I still have my second plane a Four Star 60 with an OS 91 4stroke which I fly to calm my nerves. My flying would put most to sleep. But how do you learn and get more confidence unless you put in the flight time? Anyway, thanks for the info on the wing and front strut.
Old 12-25-2004, 11:28 PM
  #52  
timothy thompson
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Default RE: GP Lancair wing failure

IF YOU GLASS THE CENTER SECTION AND EPOXY THE ROOT RIBS YOU WILL HAVE NO PROBLEM GET A ROBART STRUT AND A SAITO 70-80 AND YOU WILL HAVE A BALL. THIS LONG THINWING IS NOT MEANT FOR AEROBATICS I DONT CARE WHAT THE BOX SAYS USE COMMON SENSE!]]
btw THE ROOT RIB IN THOSE PICS WAS NOT EPOXIED AT ALL IM NOT STUPID AND THEY DONT PUT qc STAMPS NOR FOLD MONOKOTE ON INSIDE RIBS . QUIT TRYING TO GET A NEW PLANE WHEN YOU SCREWED UP
Old 12-26-2004, 01:15 PM
  #53  
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Default RE: GP Lancair wing failure

i hear a lot of people complaining about gp quality and i have never seen any of these problems firts first hand or heard anybody complainiing about them in my area and alot of people around here fly arfs, i have a gp tiger moth and i fly the hell outa this thing and never had any problems whatso ever, even know someone with a lanciar and they have never had any problems with it. my personal opinion is that u cant trust these planes which they make about couple hundred a day, u cant really produce a product that is free of defaults and anybody that trust a plane made by someone who doesnt really know much about planes or kits or rc none the less just there for the 7 dollars an hour, i dont want to fly around cause they r dangerous just asking for trouble, u should always reinforce the major areas of the plane ie firewall, wing, i have seen a lot of people on the net with failures but that was because they didnt take the time to make them safe, some of u may know of all the problems with the corsair firewall from hanger 9, a buddy of mine has one, put fiberglass on the firewall and never had a prob, its a great plane, if people were not so stubborn and just make their planes safer they wud not have all this trouble with their plane. btw i built the tiger moth stock with no reinforcing and it has never had a prob, i did inspect the plane very well, i have heard of people saying that they hot glue some of the components, mine was epoxied, the root ribs were very nice, yes mine also used the sandwiched 1/8 ply wing joiners, never had a prob with HIGH G manuvers with a biplane! just my 2 cents
Old 12-30-2004, 04:51 PM
  #54  
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Default RE: GP Lancair wing failure

Racer-

More likely they are making 7 dollars a day in most of the countries where ARF's are assembled these days.

Bruce
Old 01-11-2005, 12:33 PM
  #55  
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Default RE: GP Lancair wing failure

Edh13:

I read the whole thing. People ought to read the RCU policies regarding posting. "...Please resist the urge to curse, flame, degrade.. and so on" It turns people (some people) off. Me for instance, usually just leave the entire forum and go somwhere else where I can find something to learn rather than to 'listen' to the diatribe of some off-the-wall character that probably knows absolutely nothing about RC flying.

G-bye.. as I am off to a different forum.
Old 03-02-2005, 10:14 PM
  #56  
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Default RE: GP Lancair wing failure

this happened to me on a split s, left wing just snapped off! third flight, YS 91 ac motor. plane professionally built by the book. didn't know there was such an issue with this plane!
Old 03-03-2005, 09:44 PM
  #57  
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Default RE: GP Lancair wing failure

Sorry to tell you this, but ARFs do not defy the laws of physics. Planes will break at the greatest stress point, that is where the wings are joined. If I ever bought an ARF I would do all I could to reinforce the weak points of the plane.

I have built 3 GP kits and I will tell you they are well made, solid kits, I have no problem with any of them. Reinforce the wing joints with Fiberglass, it will add considerable time to the life of your plane.
Old 03-04-2005, 04:37 AM
  #58  
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Default RE: GP Lancair wing failure

I think that this thread is just going around in circles! (A bit like my Lancair with one wing!)

The basic argument is that, as supplied, the great planes Lancair is structurally weak at the wing joint IF you follow the instructions and do not add any further strengthening.

If you do add some strengthening, be it a wing bandage or whatever, the problem will probably be resolved.

However, the other argument is whether you think that an ARTF should be flyable and safe if you build it as instructed.

If I went into my local car showroom, bought a brand new car, and had to drive it home and weld a huge girder across the chassis, I wouldn't be impressed.

If Great Planes re-labelled the packaging ARTRCARWJ (ALMOST READY TO REMOVE COVERING AND REINFORCE WING JOINT) then I think that that would be fine too.

Let’s draw a line under the whole sorry episode and get on with enjoying our hobby!


Old 03-04-2005, 04:47 AM
  #59  
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Default RE: GP Lancair wing failure

Gotta agree with manks - this GP kit is the best ARF I've ever seen.

Well, the big weekend is coming... the Lancair is going out for its maiden.

Thanks to the contributions here, I've made a few tweaks:

- filled the "hollow" parts of each root rib with scrap ply. Glued in with 30 min epoxy. Gives more surface area for the wing root join.
- 3 hour epoxy wing joiner, root ribs.
- glass cloth 4 inch wide, top and bottom (re-covered the bottom with some spare monocote. Didn't bother with recovering the top - ya won't see it anyways).
- replaced nose gear with dual strut (Fultz).
- remote glo starter.
- cowl screw points extended with ply blocks (glued to firewall)
- thin aluminium plate cover over main landing gear join (I thought this was the weirdest thing about the kit. A two piece main landing gear. Why???)
- 3.75 dubro wheels all round.

Hopefully, no wing departures during flight.

Only other issue with this kit were the flap hinge slots. Someone was having a bad day at the GP factory and wasn't looking when using the slot cutting machine (they were cut near the lower edge, not upper edge).

-BK
Old 03-04-2005, 08:18 AM
  #60  
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Default RE: GP Lancair wing failure

Doesn't sound like an ARF to me. More like ARM (Almost Ready to Modify). Anyway, good luck with your plane. I hope you get many years out of it. My friend got 1 & 1/2 flights on his. Warranty denied on everything. Plane, motor and radios were all destroyed. [:@]
Old 03-09-2005, 06:58 PM
  #61  
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Default RE: GP Lancair wing failure

hey guys no matter what was said or not said this tread is helping other people like me on making sure to get a strong bond when joining the wing on our lancairs at least mine which i am putting togther this week
thanks to all
dc

www.cybul.com
Old 03-29-2005, 06:47 PM
  #62  
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Default RE: GP Lancair wing failure

Have been flying the Lancair for some time with the standard instructions - no issues. For those of you who do not like to rip holes in cowls, you might want to consider the RCV91. I used this motor as it is low profile and does not have a rocker cover. Fit's very well sideways in the Lancair - On-board glow driver, direct exhaust vent using flexible pipe - great performer all round
Old 03-31-2005, 09:30 AM
  #63  
Torqued-Up
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Default RE: GP Lancair wing failure


ORIGINAL: 8178

ORIGINAL: warren

Did you epoxy the root ribs? Looks awful dry...

Doubt if that would have helped much!

If you don't read the instructions...

You get the destructions...


Old 03-31-2005, 09:58 AM
  #64  
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Default RE: GP Lancair wing failure

hi there i decided on the os 61 fx i sert it inside the cowl and the only xtra hole is the one for the nedle extenxion

see pictures at www.cybul.com/rcguide.html

bye for now
Old 03-31-2005, 02:15 PM
  #65  
edh13
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Default RE: GP Lancair wing failure

Gees, Friesian can't we make this thing go away?
I'ts real uncomfortable having a thread resurface every couple months in which I sound like a complete fool.[&:]

I know, I know, I deserve it...
Old 03-31-2005, 03:23 PM
  #66  
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Default RE: GP Lancair wing failure

there is not such thing as fools on this hobby they are just i want to go fly now mistakes.
which help averyone else.


happy flying
www.cybul.com/rcguide.html
regards
david


Old 03-31-2005, 03:35 PM
  #67  
friesianflyer
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Default RE: GP Lancair wing failure

edh13 I'm with you there!
I want it to go too.
Old 03-31-2005, 03:49 PM
  #68  
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Default RE: GP Lancair wing failure

hahahahah
bye guys have fun

david from san andres island where most of the flying is done fromn water at sea

how about a lancair on floats

bye
Old 04-03-2005, 12:04 PM
  #69  
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Default RE: GP Lancair wing failure

To any new guys starting out, and to all ARF fanciers likely to purchase a ready built: After 25 years in this hobby, you tend to learn a few things,[X(] and the first one I was taught in building technique, is to always, and I repeat always, fiberglass the center section of any wing panel you join. NO EXCEPTIONS AND I DONT CARE WHAT ELSE YOU ARE THINKING OF!!!! No joiner no matter what the material is made out of, will prevent wing fold over during a high "G" maneuver, without a good and proper fiberglass job! If you already own an ARF, and you assembled the wing halfs just with epoxy, fiberglass your center section NOW!!!. Put on some Nitrile or latex gloves and apply plenty of 30 minute epoxy for joining the root rib ends and associated joiners, (wipe off any excess with denatured alcohol) check and re-check then fixture the dihedral with end spacer shims and weights, let set. Failure to "set in place" the dihedral during curing can ruin your wing![&o] Remove at least a 3 inch wide strip of original covering in the case of an ARF, top and bottom of the center section, (use a brand new #11 blade and press very very lightly not to cut into the sheeting!!!!!) Now we do the bottom first: Apply a low tack painters type masking tape just at the very end of the recently removed covering, staying on the covering, not the wood, its ok if a little epoxy wicks the end of the covering by maybe 1/16 of an inch. Remember all this fiberglass work will soon be covered again with Iron on! We now are controlling where the extra epoxy will be going! [>:]Sparingly brush some well mixed 10-15% thinned out 30 minute epoxy over the newly exposed center section, (use denatured alcohol and an acid brush. Dont over thin the glue! Mix the epoxy first very well before thinning), apply the fiberglass strip (cut it an extra 4 to 6 inches long) onto the thinly applied epoxy and position it centered and parallel to the joined center seam. (Dont ever try this with medium "CA" as some instructions say to do, its way too brittle after it cures, and the fumes will lock your heart right up!!![:'(]) Tape the ends of the fiberglass tape to the opposite sides of the wing, (the top of the wing where you are not fiberglassing) with regular masking tape, wrapping over towards the top, and pulling it as tightly as possible. (Use a three inch wide strip of glass on planes weighing over 12 lbs.) Continue to now wet and cover the top of the glass sparingly with the thinned out epoxy, until the white changes to translucent. Push the glue into the weave with the brush, or try your gloved finger tips, as just a little epoxy goes a long way here. Keep the gloves cleaned off with alcohol, so you wont mess up the rest of your covering. Allow adhesion and purchase, to extend a 1/2 inch onto the end area, past the center line of the leading and trailing edge, onto the opposite side of the wing. When we do the other side, this gives us eventually a one inch over lap, and its strong as steel. [X(] You may decide to follow up with another layer while still wet, but cut it an inch wider on both sides. I personally think it's over kill at that point, and adds unwanted weight. Only a big quarter scale or third scale project demands the second layer. Get your fiberglass wing joiner cloth at an automotive body repair supply house, it's usually a heavy grade like 5 to 6 ounce cloth, and a single strip is plenty. If you purchase cloth from your LHS, specify 5 or 6 ounce cloth. Dont bother with finer weaves, they're way too weak. Now here's the big secret to a glass smooth perfect fiberglassed joint: Cover the wet glass with a 6 to 8 inch wide strip of plan protector or even better, some old discarded mono-cote plastic backing. (You can consider taking off the gloves at this point too) Spread and work the glue in and across the joint area, but don't push too hard allowing it to migrate past our low tack masking tape borders. Two seperate paper towels to smooth it with in both hands, makes it nicer. Continue to smooth it down for a while, and In about 20 to 25 minutes, try lifting one end in a quick jerk. If its still tacky at this point, rub the plastic back down, and wait 5 more minutes. (It makes a distinctive ripping sound when its ready to remove) When you can shear a corner of the plastic sheet off the epoxy without any stringy adhesion, continue to remove all the smoothing plastic, and after 45 minutes, slowly and at a sharp angle, remove the low tack masking tape. Let set overnight and do the same again for the other side. Do not allow the epoxy to cure completely with the smoothing plastic on top, you might not be able to remove it at that point! Sand off any raised fiberglass before you start the top, and repeat all the steps again. If you do a good job, you will be able to stand on the center section and it will hold a 200 lb. guy without collapsing. (but dont try it though! Duh)[sm=bananahead.gif]
"What goes up, will surely come down"
And: "Haste Makes Waste, so fiberglass your wings religiously!
Dave the Rave...
P.S.: Let me know if you liked this method......
This is Elmo in my 1/2A Herr Engineering Cherokee: Norvel Powered (smallest project so far)
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Old 09-06-2005, 07:35 PM
  #70  
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Default RE: GP Lancair wing failure

Hi Guys
I fanally finished the lancair , i flew it to barranquilla for its maiden flight which will be this coming weekend.
i reinforced the wing mildly i guess since i did not fiberglassed it totatlly just a 2 inch by 3 inch patch in the center above the joiner
and put an aluminum joiner to make the landing gear feel like a one piece landing gear.
I will see and comment later on

regars
david

ps I also put 1.25 oz of lead in the rear aluminun joner pipe, the one at the back feathers

bye now

www.cybul.com


Old 09-09-2005, 12:00 AM
  #71  
Balsa Master
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Default RE: GP Lancair wing failure


ORIGINAL: friesianflyer

Just as an update, it has taken about 7 weeks, but I have now received a full refund on the model.

Its such a beautiful model, and really drew a lot of attention, but I just can't feel confident in flying another one.

Sort out that wing joiner Great Planes!

theres this great stuff... carbon fiber... fixes all those problems
glad you got your refund though
Old 10-05-2005, 10:20 AM
  #72  
EBHolmes
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Default RE: GP Lancair wing failure

I'm sorry for the guys who lost their Lancairs due to wing center joint failures. I've been building kits for over 30 yrs and this was my first ARF. My experiences with GP kits have all been very positive. Overall, I was very impressed by the quality of fabrication and construction. Because of my building experience, I did glass the wing center section without a second thought. It SIGNIFICANTLY increases the strength of the wing center section at a very low weight penalty. It adds very little to the overall building time and can also compensate somewhat for a less than perfect mating of the root ribs. I can understand those who believe that an ARF should be safe to fly if built per the instructions. I think that GP should instruct builders to glass the wing center section. However, my overall experience is that this is a fine product. I've been flying mine for about 2 years with no problems. I will replace the nose gear because it is too soft. The O.S. .61 FX powers the model well and allows for a completely cowled in engine and exhaust system. It performs in a very scale like manner and is not underpowered. While I still prefer building from kits or plans (for me building is at least half the fun of this hobby), this ARF is a fine semi-scale rendition of a beautiful aircraft. I hope that this thread doesn't deter people from building and flying this product.
Old 10-05-2005, 01:21 PM
  #73  
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Default RE: GP Lancair wing failure

Hi EB
My lancair also has a .61 fx but ithink is over heating can oi see picture of the cowling where the air comes out after it comes trough the cowling and out the bottom.

i think i made mine a bit small but dont know

it gives me better rpm uncowled than cowled

regards
david
Old 10-05-2005, 10:07 PM
  #74  
EBHolmes
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Default RE: GP Lancair wing failure

David,

Did you put the baffle in the cowl and install the exhaust air panel in the fuselage? I did and I haven't had any problems over heating. I also run fuel with a castor/synthetic blend. Castor oil has better heat transfer properties than synthetic lubricants. I don't have any photos of the details.

-Eric
Old 10-06-2005, 09:36 AM
  #75  
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Default RE: GP Lancair wing failure

Hi Eric

Yes I did put the baffle and the exhaust tray on the fuselage i did not open enough the bottom of the cowling i think i made it precise around the gear strut and the exhaust extension so that the area for the air to go out is smaller than the one come in from the front of teh cowling, yesterday i increase`this so thatthe area is at least the same as the one coming in will let you know as soon as i try it some time later today.

regards

david

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