"Bug" DLG

[Craftydan]

Tex,

About Torsion-springs . . . the longer the twisting section of wire, the more the same twist is spread across it's length, the less spring force it generates.

I can't see the rudder spring from your pics, but the elevator looks like it's at most an 1/8 of the span. While that would be a reasonable spring size for my larger DLGs, they also need more force than the bug and have tails built for the extra punishment. while the longer spring adds more weight, it's far less than the matching pushrod.

One other thing to consider . . . Instead of a "U" shaped spring, how about a "L" shaped? effectively take a longer U shape. then bend it in half. so long as the wire doesn't break on the sharp bend (it shouldn't . . . the first time) you'll get the spring force associated with the longer piece of wire, form a smaller assembly . . . with NO twist warping the surface.

They're a touch harder to do than the U-springs and if you're not careful about how you cut the pocket they lean out . . . but they work.

 

[TexMechsRobot]

The "L" shaped spring is interesting. I think my biggest issue is the flex in the surface (the pictures don't show it) when I hook it up to a servo with the string. There is about a 1/4" wave (crest to trough) running lengthwise. I think I'm going to stick with the pushrod for now since it's already installed and it should be easy to revert back to spring-pull in the future if I decide to. I have a feeling that I'll be rebuilding most if not all of this at some point since this is my first DLG style build and it seems unlikely that everything is perfect the first time

 

[Dumitru Ivanov]

Love the yellow model, mate. Did you buy the blade?
_____________________________________________
Dumitru
Customs broker Montreal

 

[TexMechsRobot]

Love the yellow model, mate. Did you buy the blade?
_____________________________________________
Dumitru
Customs broker Montreal

Thanks! No I made the blade from two strips of carbon fiber, kevlar thread, and CA glue. I'm not sure yet if it'll hold up to launches though since I haven't had the weather to maiden it. I'll post here when that happens and I have something to report and some video to show.

 

[FAI-F1D]

I'm not sure yet if it'll hold up to launches though since I haven't had the weather to maiden it.

If you manage to break that peg, it's time to take up competitive DLG flying. Seriously, .018 carbon is pretty stout stuff.

I think my biggest issue is the flex in the surface (the pictures don't show it) when I hook it up to a servo with the string. There is about a 1/4" wave (crest to trough) running lengthwise.

Sounds like your spring is too stiff. A finer gauge wire would be the solution. Honestly, I'm using .010" wire in my springs on DLG's these days. For 1.5m gliders I'm using two springs from .010, each about 2" long. For 1m gliders, one such spring is usually sufficient.

For what it's worth, my Bug and Superbug used pushrods, but I could have saved a lot of weight by going to pull springs, and would have had less slop in the controls to boot.

 

[TexMechsRobot]

I finally got a few throws in today. It was a little rainy and windy but I felt the conditions were enough that I could still test the balance and flight characteristics. I am VERY glad the ground was soaking wet. I literally lawn darted it a few times and it just sunk into the lose, wet dirt a few inches.

I've posted the video below of a few throws. I probably did about 10 HLG tosses and about 10 small DLG tosses. I'm only showing a few here. Based on what I saw, I have two diagnosis.

One: It is tail heavy. This is evident by its tendency to flip onto its back when I initiate up elevator. I think it is very tail heavy in fact. I plan to add about 7-10 grams right up on the nose to bring the balance forward.

Two: The throws may be a little too drastic. My radio doesn't have the capability of limiting the throws or adding expo so it was a little tough to control at high speed right after throwing it. Once the speed dropped and I got control of the tail heavy tendency, I could get a few seconds of semi-controlled flight at the end of a glide.

I think adding nose weight first is the best solution. Then I'll adjust the throws if needed.

 

[David J]

Looks cool! Got some pretty good flight time.

 

[Craftydan]

Swapping out the pushrods for strings will move the balance forward, but you may still be looking at adding a touch of ballast. If you haven't considered a light-glass job on the pod, now's a good time -- you'll pick up strength and ballast where you need it. In the mean time, slipping a penny in the nose may be enough to get a good glide -- 3.1g/ea before '82, 2.5g/ea after, and cheap Load up the ballast dry (laying in the fuse, not glued in) to get a feel for how much the CG moves. probably won't be by much, but really doesn't have to be. with as reasonably behaved she is (despite being unhappy) you're pretty close now to neutral, so you're within a small fraction of an inch. Tape it in when you're happy with the new CG point, and go fly

If you can, move in a hole on your servo horn, or cut a new hole farther out on your control horn. either of those should reduce the throw mechanically. Creating mechanical expo . . . that's a bit more complicated -- best to wait for a new radio for that.

For a maiden, great job!

You've got a sweetheart in the making

 

[nhk750]

Looks good, ya I would say tail heavy too.

 

[FAI-F1D]

yeah, that's waaaay tailheavy. And I think the control throws are excessive too. But, it's still in one piece, and you flew it.

 

[TexMechsRobot]

yeah, that's waaaay tailheavy. And I think the control throws are excessive too. But, it's still in one piece, and you flew it.

"Flew" is going a bit to far lol.

 

[paulshort]

Thats exactly what my first one did. Add some nose weight and reduce the throws waaay down

 

[flyboa]

First try at a balsa DLG. 36" wing built from salvaged balsa no plans.

 

[Pijje1]

hi newbie here

hi there to you all what a great thread I am thinking of building a bug here in the southwest of the uk lol

I have a couple of questions and a thought for the future lol

1. I have downloaded the plans and files for the bug thanks for that but I was wondering how do I print them do I just print then as they appear in the pdf or do I need to scale then at all ?

2. was thinking of using a spectrum brick rx and 2 servo is this a good idea or better to get proper servos and rx ?

3. can I build this to hand launch as have back problems so cant do the discus launch ?

4. had a though could I put a motor in the front of the bug ? was thinking this
motor ap05-3000kv-brushless-micro-motor-5-4g
and esc is a Oversky XP-7A ESC
battery wise are 300mAh 1S lithium polymer with E-flite micro connector 3.7v
props I have are GWS 5030 5x3

was a thought as have these all spare from some microace planes I have and fly

hope you guys can help as thinking of starting soon

cheers

Paul

 

[TexMechsRobot]

The original Bug was a hand launch with the launching peg being horizontally placed just aft of the bulkhead that separates the battery/RX from the servos.

 

[Pijje1]

hi there

hi there

oh right ok that is cool so that is no prob then how about the plans do I print straight from the pdf ? and is my choose of electrics any good ? or even to add a motor lol

cheers

Paul

 

[TexMechsRobot]

I haven't tried or even thought about adding a motor so I can't really help you there. Concerning the PDF's, that depends on your file. However, I suspect you can just print it at 100%. I got mine from Outerzone and they were 1:1 scale.

 

[Pijje1]

hi

hi all

oh right ok thanks for that will print a few off at 1:1 and go from there and also did download the on from Outerzone so see how it goes and maybe someone on here can give me there thoughts on the electrics and about putting a motor on it

cheers

Paul

 

[Craftydan]

Personally, I side with the "shes amazing without it", but if you're looking to put a motor on it, I wouldn't go with much more punch than what you'd find on a champ or vapor.

The airframe can take it, but the balance and weight of a motor much bigger will probably leave her . . . unhappy. Champ guts, IMO, would be perfect.