gp lancair wings snapping
 

what's left of a great planes lancair. this guy was flying this one in a slight climb at medium speed and the wing snapped just short of the center section. this is the 2nd one these i seen do this in the last 6 months!. the 1st one i witnessed several months ago ,the flyer was doing a inside loop and when he pulled out the wing did the same thing this one did. anyone else heard of gp lancair's doing this?. hope the pictures uploaded

RE: gp lancair wings snapping
 

I've got one of these and so far (knock on wood) I haven't had any problems. There's a pretty good Lancair thread here on RCU somewhere and one of the first things recommended is to get the wings halves epoxied together and then take off about 1.5" on either side of the root and glass the whole center section of the wing with 3" fiberglass, top and bottom. From the sounds of the type of flying that was being done it was more scale than acrobatic, and that's one thing with this plane you've just to keep in mind, it's not for hard aerobatics. The only thing that concerns me about the pictures posted though is the fact that it looks like it busted right on the outside of what would be the edge of my fiberglass job [X(]. The Lancair thread is either in the ARF of Scale forum. Sorry for the loss of such a beautiful plane.

RE: gp lancair wings snapping
 

its common sense to glass the center section . Experienced modelers know this. I think GP has amended the instructions and mention glassing. I do rolls and loops but im very careful on the power.

RE: gp lancair wings snapping
 

This plane has long slender wings ... best to glass them or even put a metal bracket to hold both sides of the UC together. Mine was glassed and she was ok. I did not pull any high G maneuvers at all. Was not flying slow but did not try any nonsense. Just you easy rolls and loops.

RE: gp lancair wings snapping
 

Well, it is not so Great Job of the Great Planes; flying it and wandering when it will colaps ...
That doesn't sound like a Great Pleasure and in addition one should fly only when the Wind
is too low speed because the gusts will do their Best to make lot of more G indeed.

Here is one link about Lancair where we were speculating on this issue.

http://www.rcuniverse.com/forum/m_63...tm.htm#6400441

It seems covering the whole(!) wing and also tail with Glass Fiber and do what comes to mind
with this plane is not so bad idea, what do you think ? For example placing even 26cc Engine
and fly it to the hell of speed and sharp turns - it is too speedy plane to fly it like a desk-top
plane... and feel sitting on needles... After seeing those pictures I am more and more convinced
that adding 10-15% weight and 1 week more work is worthed. Any other ideas ? Maybe
someone will produce better Lancair after all those accidents.

Sorry for the poor guys who got their beautiful birds in pieces; might be feeling too bad ...

RE: gp lancair wings snapping
 

My personal take on this is very simple. If you fly her slightly faster than scale then its still ok ... this is not a pylon racer for sure. Still, its true, this GP plane has too many failures to say it was the fault of your average hobbyist. Its the same situation with the H9 Funtana 90, problems are there but they sell like hot cakes.

RE: gp lancair wings snapping
 

Happened to a club member last year. Looks like about the same spot. He was just pulling through a turn when it snapped In two.
Great Planes/ Hobbico sent him a new ARF no charge. I would have your buddy contact them and get a new kit.

RE: gp lancair wings snapping
 

Tianci,

There is the "trick" - to fly it like a Pylon-Racer and to think that we are in Reno circle ;)
Well, as I wrote you last time in that forum, I came to conclusion that almost any ARF is
worth "fortifying" well so the number of the maintenance "repairs" after all is lot less and
the plane "wears-off" after many more years. Surely it is a self teasing exercise instead to
put the things together and fly after a day or two it takes week or more but then it is very
long time pleasure. Of course someone could still mention that "pleasure" means different
things to different people...[sm=spinnyeyes.gif]

Cheers,
Nikolay

RE: gp lancair wings snapping
 

Hey, someone beat me to it!:D [8D] I was going to post it on the big Lancair photos thread
but stumbled upon this.

I am/was the said owner of this model. I believe an earlier wing strike might have lead to the
beginning of the end here. I was doing my normal approach, full flaps, steep approach when the
plane ballooned on the flare and tip stalled causing the wing to hit the ground. Very ugly
landing!:eek: Now it didn't hit hard (just bent that high quality nose gear a bit;)) but, I guess
it doesn't take much with the long wings. In retrospect, I should have checked the integrity
of that wing before I flew it again but in my haste to achieve the pretty landing, I flew her
again, climbed to about 100 ft.and "pop"! Flew straight down.

Definitely check the wing after any strike of any kind. Even if you glassed the wing like I did.
Here's a few photos of where the wing broke...

I will truly miss it. It's a nice flying aircraft with scale landings and approaches.
Hope to have another soon as I have no other home for an FX.61 and TF in-cowl
muffler.

RE: gp lancair wings snapping
 

Nikolay - well you are right, its worth investing in some extra work, sometimes it might not just meet Earth but rather someone or some child.

Sportflyr - that's sad, looks like this plane is a good looking one and the wing is not that solid. Anyways, I sold mine to a friend and I got another in my hobby room that belongs to someone else. Sure looks good for an EP conversion project!

RE: gp lancair wings snapping
 

Tianci...

Definitely a gorgeous airplane but just a tad under built in the wing area. I became hooked
after my first smooth crosswind landing. There's just no other airplane like a Lance and this model
really captures it's spirit.

This is a laminar flow wing just like it's full-scale bretheren and unfortunately with a fully sheeted wing,
there's no way to really check for damage by just peeling covering. The one thing I REALLY dislike
is the fact that the grain in the webbing of the box-spar run up and down...this is really
a terrible practice when building wings and I think GP should really correct this.

I would love to see this model fly electric but, I've got to utillize the nitro stuff laying around!

RE: gp lancair wings snapping
 

Ahhh... Sportflyer:

The grain is supposed to run up and down. The purpose of the shear web is to keep the spars from coming together. The stress on the webs is diagonal and it shifts 90 degrees when the wing goes from positive to negative G. The best compromise, to align the grain with the direction of the average stress, is to put the grain vertical.

Jim

RE: gp lancair wings snapping
 

sportflyr - go to RCG and you will find one Lancair in EP and its totally overpowered. That baby has 2,000+W ...powered by a Neu motor too. Mad bugger ... running on only a 13 or 14" prop. Not heard that she has crashed yet. :) EP is the way to go ... planes last longer but lesser flight duration and the kids' college fund will also be low! Hehehehe ...

RE: gp lancair wings snapping
 

Still, the price you pay per hour flight on batteries might be as much as 10-20 or lot more times higher
than on methanol, isn't it, those batteries do not last more than 20-30 times and cost about at least
200-300 if not over 500 USD per pack. I will stick to the mathanol+castor till the batteries get about
10 times cheaper ... that is maybe after 3-5 years ...

RE: gp lancair wings snapping
 

LiPo batts should last about 200-300 flights, so divide the batt cost by that to get your cost per flight to compare with fuel costs. Problem is, if you damage your battery pack in a crash, or by over-charging or over-discharging before the 200-300 flight lifetime, your cost per flight goes up accordingly.

Basically, buying LiPo packs for your planes is like buying fuel for 200-300 flights up front, and that's quite a bit of nitro!

RE: gp lancair wings snapping
 

You are too optimistic but you still need to supply some convincing specific numbers.

I wander where do you get from those 200-300 cycles batteries and how much they cost ?
LiPo at high currents seldom lasts more than 30-50 flights... Please post the type of the batteries,
their price and the currents you are draining from them, as well the www-page one can get them
from. Sure, LiPo last in my LapTop up to more that 1000 cycles but that is a very different story.

Meanhile lets calculate what the real (!) case is in the following size of engine i.e. to get our
talk to a real case, then we can see if we are talking about the same thing:
- If I suppose to replace my OS.91FX with electric, I would be in fact replacing 0.5 liter of fuel
per flight with electric charge/discharge. In favor of your suggestion I would think the cost of
the electricity is 0.0. Then for half liter Methanol with 20% Castor in it I am paying in total about
less than 0.45 USD, lets take it to be even 0.5 USD. Then for 300 flights it will cost me about
150 USD. Do you think electric can get even near that and also how much the Hardware will
cost compared to the 200 USD for .91FX, assuming that it should deliver prety similar power ?

RE: gp lancair wings snapping
 

This old wives tail just won't go away. Glassing the center section of properly joined wing halves does nothing...
All you're doing is reinforcing the sheeting. If the wing is so poorly designed or joined that the sheeting is sharing the load than it's going to fail somewhere else anyway, unless you glass the whole thing. Case in point, look at the pictures of this wing. It was glassed, and broke at the edge of the fues! You will have a hard time finding a picture of an epoxied joint where the epoxy failed and not the wood.

RE: gp lancair wings snapping
 

Actually your laptop most likely has Li-Ion, not LiPo, and I doubt you get anywhere near 1000 cycles out of it.

A friend of mine flies large 120 size electric 3D planes, and he gets ~300 cycles out of his packs before the performance degrades. I believe he uses Thunder Power packs. Unfortunately, you get what you pay for with LiPo packs, the bargain-basement packs will probably die out after 30-50 flights, so your best sticking with the well-known name-brands.

Nitro fuel is anywhere from $12 to $20 a gallon here in the US (depending on if you can buy it in bulk or have to pay hobby shop prices), so half a litre of fuel costs $1.59 - $2.76, and 300 flights would cost $477 - $828.

I'd sure like to know how you get nitro fuel for $0.90 a litre, that's $3.40 a gallon! I find it hard to believe that it's that much cheaper in Finland!

RE: gp lancair wings snapping
 

If you check the books and manuals for Li-Ion and LiPoly the authors will tell that both have
a theoretical limit of up to even 20,000 cycles and no memory-effect etc, but then they explain
how those numbers get down to 100 or less and talk a lot how the wear-off occurs, calling it or
not memory-effect. Capacity of every battery goes down faster with the higher currents you use.
Surely there might be some capacity even after 500 cycles but the duration fo the flight might be
about 1/10 of the first flight duration. I guess your friend does not just decide like that to stop
using those batteries after 300 cycles, isn't it. ;) He is forced to stop using them because they
have no more capacity of any use.

You did not mention a price, but here is what I see to be very discouraging even after several
years of Li-euforia:

http://www.hobby-lobby.com/katana50.htm

That thing needs Two - PQ33003 PolyQuest "Twenty-Five" 3 Cell 3300 mAh 11.1V LiPo Battery
Pack @ $ 119.90 ea., which makes $ 239.80 and that is for 0.5 engine similar performance.
Thus for 0.91 perfoamnce the price might come badly to about 500 USD or more.

And even if we say that the Controller and motor jointly are similar to price of OS.91 then the
price of the smart charger is comming on top with about 200 USD more; any fuel pump is only
below 20 USD.

One liter of methanol is about 0.6 Euro and one liter of castor is about 2 Euro per liter all from companies
which use them to make their main prodictions. Surely it is case without Nitrometan and I do not want to
put money to the pockets of the RC-Shops for fuel. It is lot cheaper outside of them.

RE: gp lancair wings snapping
 

Makes sense but, having not built for a while, that was
one of the first things that came to mind AND an old timer
at the field wondered why the grain was running "the wrong way" but,
I'm sure there are arguments supporting his theories too.
I tend not to argue with veterans in the sport and now that you explained
it so clearly, I can definitely see benefits of running the grain vertically...

Thanks for the clarification![8D]

RE: gp lancair wings snapping
 

Sorry for triple posts...having trouble with the site.

RE: gp lancair wings snapping
 

Tianci..

I'll agree with the college fund theory. I basically reserve electric for the
smaller parkflyers as they are cheaper and anything beyond a .40 size electric
just doesn't make sense to me right now. I am also waiting for the lipos
to be reduced. Then maybe.

I'm certainly not knocking electric though...Zebe from Esprit Model flies some of the most
incredibly performing airplanes I've ever seen! Here's just two examples.

I'll have to check out that E-Lance though as I just love these
airplanes.[8D]

RE: gp lancair wings snapping
 

And I thought that only happened to World models T-34's on a regular basis

RE: gp lancair wings snapping
 

glassing the center adds tremendous shear strength. the wood undulates as a sine wave in fligt. the glass helps hold it together

i have gp lanc and never had a problem. hitting a wing on landing will cause damage. the wing spar could have been damaged. the wing can be fixed as well as the fuse. might need new windows

RE: gp lancair wings snapping
 

I don't own one of these models, but from what I can see from the posted photos is that it would appear that the wing joiner was not glued to the main spar....that's why you have that lateral "slice" taken out of the bottom of the wing sheeting. If that's the case, then the wing joiner was merely aligning the wing halves and added no structural integrity to the entire wing.

Glassing the center section of a wing---- I'd do it for a balsa sheeted foam core wing but not neccesarily for a built up wing.

Saginaw......Cool! 1/2 of my genetics are from the Owendale/Cass City area:D