Meesh

My Feedback: (135)

Rick,

Not that I can think of. After all, it should be able to fly the plane inverted and keep running. You can mount a single upright or inverted no problem.

Bob

RickVB

My Feedback: (24)

Meesh, yeah I know, but I didn't know if there was something special about the twin carb setup. Shouldn't be, as far as I know, but then again what do I know?

Meesh

My Feedback: (135)

Rick,

Only difference with twin carbs........a little harder to set up.

scottfl78

You all still flying these Lancairs? I have always liked the looks but after reading all the wing buckling stuff I am kind of shying away from it.. Have they redesigned the wing by chance? Also the cause seems to me to be the lack of of strengh at the 25% mark going outboard from the center of the wings.. Isn't that where they are breaking? Everyone seens to think they need to glass the center section but that does nothing to the rest of the wing.. wish they would have gone with a sheeted foam core wing.. These are some wide wings to be built so cheaply..

mimoore67

My Feedback: (51)

Scott,

Look under scale forum, as there is a ton of information on how to improve on this awesome model.

I had the folks at www.tntlandinggear.com make up a single piece landing gear, which reduces stress on the wing. In addition I removed the covering and fiberglassed the center section of the wing for added strength.

Read all you can on this model andyou be suprised of the minor modificatins you can make to have a very cool airplane

iFLYrc_Vic

My Feedback: (6)

I've got two of these planes and have not had a wing failure yet. However, I am not one to "put it through the paces" as some RC flyers do. I perform "mild aerobatics" and limit the high stress maneuvers as I do with ALL of my planes. I've got over 40 flights combined on my two birds and I love them both.

Unless you are p-lanning to perform high stress maneuvers, glass the wing joint and you will be fine....

dave_rose69

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, 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 halves 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! 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. (Don’t 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 won’t 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. 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 separate 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......

chrisdev01

Add me to the list of Lancair owners that have experienced wing failure:

http://www.rcuniverse.com/forum/m_65...tm.htm#6624766

casniffer

My Feedback: (1)

Hi,
Here are the modificaitions I did to combat any potential wing failures. Its a thin wing and any additional strength is advantageous.
I didn't like the light ply joiner that came with the kit. It wasn't thick enough and wobbled front-to-back and up-and-down in the joiner socket. I believe this has a lot to do with the wing failures...no solid mechanical bond. I decided to fabricate my own out of aircraft ply. I sandwiched three layers of carbon fiber, the middle layer at a bias to the outer layers, between aircraft ply with 30 minute epoxy and clamped overnight. I traced the outline of the original joiner and cut out the new joiner. I sanded it to snug fit the joiner box with just enough room for epoxy.
Also, if the covering is not removed from the wing roots, they won't make solid contact with each other during epoxying. There isn't much surface area to begin with since the ribs have lightening holes. A razor plane made quick work of this. I estimate 1/4 of the wing root surface has covering on it. I used rubber bands around the leading edge dowels and around the flap openings at the trailing edge to clamp the wing together during epoxying.
The split landing gear also contributes to wing failures. A hard landing directs all force to the wing root. I made some straps out of aluminum to connect the two gear sections together. Now all I have to do is fly it. Hope this information keeps other Lancairs from suffering wing failures.
Thanks
CAsniffer

iFLYrc_Vic

My Feedback: (6)

Casniffer, you have made some very good mods that don't require a lot of work or extra expense. They should increase the strength of the wing joiner joint. I lost one of my Lancairs due to pilot error on landing (got her too slow with too much flaps - stalled - power on recovery resulted in a snap). If is build another one, I will certainly use your mods, however, my Lancair is built exactly as the directions indicate - no problems with well over 40 flights.

SDCrashmaster

I suggest we start a couple more new threads on "Lancair wing failures".
That way, we can have four of them running simultaneously

What's the deal here guys?[:@]

Gerac7

My Feedback: (271)

My wing split in two first fight! Very depressing! P.S. I am an excellent builder.

iFLYrc_Vic

My Feedback: (6)

Wow! Did it split in the air or when landing? Did it separate at the joint?

I guess I built my Lancair very strong, fly it very gentle, make smooth landings OR all of the above.

casniffer

My Feedback: (1)

Gerac7,
Did the wing fail at the joint or outside the joint? Did you remove the covering on the face of the ribs? Did you test-fit and notice if the wing joiner was loose in the joiner box? Did you use 30 minute or 6 minute epoxy when you joined the wing? Was your first landing a little hard? I know this sounds like an interrogation, but all these things are valid, important questions.
About 1/4 of the glueing surface area of the wing root is lost because of the covering...and since its on the outside of the root makes it even worse. The manual doesn't mention removing the covering. I re-read the section on joining the wing. If the wing joiner does not fit snug in the joiner box, you are depending on the epoxy alone for strength. As soon as the joiner is subjected to enough stress, the epoxy fails causing the joiner to slip, resulting in the covering peeling away from the wing root. The rest is academic. 6 minute epoxy doesn't penetrate the wood like 30 minute. If the joiner is snug, it should not move and the wing should be able to withstand more stress. Fiberglassing the center section would increase the wing's strength as well.
Whenever I buy an ARF, I do some research out here on RCU and RCGroups. I learn what others have experienced and apply whatever I think will correct.

Thanks
CAsniffer

edh13

My Feedback: (9)

CAsniffer's assy mods make sense. His wing will never fail at the center and he didn't have to glass it. Unfortunately it looks like these wings have a tendency to break outboard of the joiner also. Not much you can do there without reengineering the whole wing.

tIANci

I am definately NOT going to maiden my friend's new Lancair! Hehehehe ... he's on his own.

casniffer

My Feedback: (1)

tIANci
I wouldn't worry about maidening your friend's Lancair. Just don't make pylon turns, snap rolls or tight loops and make a soft landing. check the CG and all the other pre-flight checks you would do with your new plane. Go with the recommended throws. I don't like flying other peoples' planes, although I do all the time. The owner assumes a measure of responsibility by offering or allowing you to fly their planes...unless you make some bone-head mistake.

CAsniffer

tIANci

CAsniffer - know what you mean about flying other people's plane, I don't like it. For me its ok to smash up my own plane but to damage someone elses is just bad. My Lancair had no issues at all, never did try to pylon race her. I still say she is a lovely plane. Purteee ... really purtee ...

casniffer

My Feedback: (1)

tIANci,
I woudn't worry about the maiden. I should be making the maiden flight of my Lancair this Saturday or Sunday. I have a Saito 91 with Slimline pitts muffler and 13-8 three blade prop. I will try to make some on-board video of a flight in the next week or so. I have the video system, but need to work up a mount for the Lancair. I've flown my Cub with on-board video and its fantastic...especially flying the plane while looking at the screen on the camcorder. There is a servo that pivots the camera view from the forward to down.

CAsniffer

casniffer

My Feedback: (1)

WooHoo!
I flew my Lancair this morning for the first time and it was fantastic. Had to put some down trim and a couple of clicks of right. It had about 25 degrees of flap and lifted off sooner than I expected. Tracked very well. With full flaps, landings are slow and require a bit of power until you're on the ground. Looks like my mods held up. I would like to make the wingtips removable...I have a good idea on how to do that. I'll put the wheel pants on this week to see if I like them. We fly off grass.
Love it!

CAsniffer

timothy thompson

My Feedback: (1)

fly it scale and it will be around for a long time mine is going on 5 years and i fly it alot! just scale power management and no hard aerobatics. i cant believe any of these failures happened in those flight constraints. Had to be a high G maneuver. Being a full scale pilot also helps in seeing the limitations of a model.

casniffer

My Feedback: (1)

Hello all. I have 8 flights on my Lancair. The last 4 carried an on-board video camera with a video downlink. I fluffed up the video a little bit so I wouldn't have to cut the music short. Here is the las

t video. No issues with respect to my mods.
Hope you all like it.

[link=http://www.trentonrcflyers.com/videos/lancairvid.wmv]Lancair Video[/link]

NM2K

My Feedback: (14)

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I understand your thinking. But one must realize that there are folks (me!) that love to fly planes like Cubs, etc., in a most unscale-like manner. Seriously.

Also, the design characteristics that cause a full size plane to perform a certain way seldom directly translate to the flight characteristics of a much smaller model airplane replica of the full size subject airplane.

Certainly, there is no engineering transfer at all regarding airframe strength, power-to-weight ratio, etc.

Model manufacturers should design/assemble model aircraft to withstand the worst kind of abuse possible, other than outright bashing the model into a hard surface. It doesn't cost that much to utilize an adequate piece of plywood for the firewall and the wing dihedral brace. Ditto landing gear blocks.

I see nothing inherently wrong with a two-piece main landing gear assembly, as long as it is designed properly and built with adequately strong materials consistently.


Ed Cregger

jrf

My Feedback: (551)

Casniffer: One of the best in-flight videos I have seen. Thanks for posting it.

Jim

casniffer

My Feedback: (1)

Thanks!
I'm getting some glare and reflections on the inside of the windshield from the tank and other light-colored parts inside. I'm going to put some black felt or other flat black material inside so the glare won't be so bad. I'll have some more videos to share soon.

Thanks
CAsniffer