The counterbalances are huge on the elevators and there is a great stress concentration right where your last hinge ends. During 3D like waterfalls with huge elevator throws and lots of power the propwash hits the counterbalance and wants to tear it off (due to the deflection the elevator presents a big cross section to the airflow and the elevator wants to bend back right where the last hinge stops). My first elevators were built entirely stock and did not last long because of this. My elevators now have less counterbalance and more corner gussets at this weakpoint and hold up fine.

Iflyit: I fiberglassed the center section of the wing with 3" wide strip of fiberglass and thin CA and this also greatly improved the strength of the holddown section.

all the way around top and bottom?

Yes, I just have a habit of doing this since it adds a lot of strength.

Glassing the center section is usally a good idea but in this case I must disagree. Other than the elevator counter-balances which are weak and need carbon reinforcement, the weak link on a Laser 3D is the fuselage. It is weak in the area right in front of the canopy where the ply fuse sides are at their most narrow. Use your glass cloth or kevlar to reinforce between the fuse side and the doubler in that area, actually the whole doubler could use that sandwich. I can speak from experience, I broke my fuse in half doing a vertical "wall", ( straight down and pushing at idle)it was quite a shock. I was asking for trouble and am not blaming anybody but myself but it did expose a weak area.

Rob

I'm using the stock setup on mine, with an OS 50SX and it's just fine. Never had a concern with it at all! I think some people just worry too much about these things.

I don't know what you guys are doing to break your Lasers, but I've done just about everything but crash mine, and it's just fine. I put NO reinforcements in other than what is specified, and it's just fine. I've ripped the one side of the elevator off 3 times now, but each time I would have rather have it rip off than destroy the whole tail! I've done more parachutes than most people have seen. Every flight I do at least one and one wall, and the elevators have NEVER failed. I touch the rudder to the ground, and as long as I don't try to drag it or something, it's just fine! If you're breaking the fuse, you MUST be doing something differently than I am. I saw one guy fly one in level flight at full throttle, and that certainly did shed an elevator, along with both ailerons. If you're adding extra weight, you're not doing yourself any favors. The lighter this plane is, the less strength it needs. The more strength you add, the more weight, and the more strenght you need. You'll find yourself in a losing battle and a plane that doesn't fly nearly as well as it might.

Icebird, glad your having good luck. I put mine through the ringer also and it was built bone stock with an OS .50 and the fuse broke in two. That's a fact and I have a couple of hundred airplanes under my belt and this one was built right. My comment was aimed toward not needing wing center section reenforcement but if you want to beef something up make it the fuse. No more than 1/2 oz of reenforcement needs to be added to the fuse to make it bullet proof by way of some 1oz. glass cloth and some CA between fuse side and doubler. Try your parachutes with a push and report back, it could be spectacular!

Happy flying,
Rob

I've done many into a negative attitude, and had no problems at all. I'm using the same motor you are, so I can't explain the difference. Perhaps there was a bit of a defect in the plywood right there on yours, anything's possible.

Has anyone thought about not installing the strips that go on the tops of all the wing ribs? Parts B6-21 I think. They don't seem like they're going to any strength. My best guess it that they're there for Monokoting. Any thoughts on that? If they are just for the Monokote, they don't need to be. My pizazz wing is set up just like this. The ultracote adheres to the sheeted leading edge and the sheeted trailing edge and thats it. No wing ribs (except of course the outermost ribs). Seems like a good place to save some weight. Any thoughts on their reason for being?

Thanks!
Reid

The cap strips do add strength! If the ribs can deform, they can cause the wing to fail. That's what happened on 2 Fun Tiger Extras that I had. The wings literally fell apart because there was nothing to hold the leading edge, spars and trailing edge in place. The amount of weight you would save would be negligible in any case, so why bother?

Ok, I'll add them in then. Just wanted to ask. Did you have to cut them? In the manual they show the guy cutting them, but this seems odd in such a nicely laser cut kit. I don't know why they wouldn't just make them shorter. They're not supposed to fit under the last 1/4" of sheeting are they? I'm having trouble seeing where they go.

Thanks!
Reid

No, they go on top of the ribs, between the LE and TE sheeting. Since there can be differences, they can't really be laser cut, as the length won't always be exactly the same. It's a simple matter to put it against the LE sheeting, and us a razor saw to cut it off even with the TE sheeting. I usually cut it a touch long, then trim it with my sanding bar to get it exactly the right length.

Gotcha. Will do!

Thanks!
Reid

Wo! I just fiberglassed the joint between the two fuse pieces. You can see my thread for my process. I tried the joint first with just expoxy and it was very very weak. It broke under my moderate hand pressure. So then I layed a small piece of fiberglass cloth over the joint and wow! It's significantly stronger. I'd recommend all who are building this kit to glass this joint.

Reid

What glues have people been using to glue together the fuselage sides, radio board and that 1 former behind the engine mount? Epoxy? I feel like I've already used so much epoxy (wing joint, fuse joint, engine mount). The step I'm talking about is the first step where you actually join the fuse sides.

Thanks!
Reid

The joint are so tight on mine that I just used Medium CA, and then when over with Fast CA.

My framing is all done, I just pick-up my engine it was back-order for a couple weeks, just sanding and covering left after installing the engine.

Daniel D.

Yeah, my joints are pretty tight too. There are a few small gaps though. I think what I'll do is use alphatic resin and some good clamping. Thanks for the suggestion!

Reid

Well, I just removed my wingtips! I've heard a lot of comments both ways, so I decided to find out once and for all which is better, or if there really is a major difference. Since I have over 400 flights on my Laser 3D, I know pretty well how it flies. I'm planning to try it out tomorrow, and I'll let you all know if I find any differences, and what they are. Hopefully, this will settle the issue once and for all.

Hello Icebird , anxious to see how it goes w/o the tips.
We have our all framed up now and decided to cut our tips in 1/2 to keep it lookin good. Here is a pic. What engine are using ? How well does it perform , IE - pul out of hovers and T/R's etc... ?
Thanks much , Rod & Chris in PA.

Well, the results are in! If you want your Laser 3D to be more responsive, have less coupling in knife edge, faster roll rate, and better hi alpha, then leave the tips off!!! I can't believe the difference! It will even do a blender after a fashion now! Elevators lock right in, with no wobble at all, harriers are so much less work, they're almost trivial now. It's not quite as stable as it was with the tips on, and lands a little bit faster, but that's not really an issue. I'm running an OS 50SX in it, and it's about 4 pounds 10 ounces now. We're at almost 4000 feet here, so performance is not nearly as good as sea level, however, the colder air today made it a bit better than usual. It hovered today at about 1/3 throttle, and full throttle from a hover starts it accelerating quite quickly. Full throttle climbs quickly go faster than I want the plane to go. In other words, I'm VERY happy with the power I have. I use an APC 12.25 X 3.75 prop on it.

Finally, after about of month of trying to make my E-streak fly; i'm back to build my laser!! i have just finished off the ailos. i heard of fiberglassing the fuse sides from one of you. is this necessary? if so; how do you do it so i tdoesn't interfere with the inside formers/shelves/trays etc.??
Good to Be Back!!

Mike

Icebird - That's what I found as well. Much better plane without the tips!

Chuck

In my opinion, it's not necessary. It's not just the fuselage sides there, several other components add to the strength at that point, and the fiberglass is just extra weight. Your mileage may vary, but I've done everything that people say will cause the sides to break, and I have had zero problems with that.

ok thanx guys; i guess i will just epoxy them then.

actually; there is a little more work on the electric; just trim though