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Mar 11, 2019, 06:13 PM
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Build Log

1M DLG Build - "Δh"


Hey everyone,

After some discussion in this thread , I decided to also post a little build log about my 1m DLG project here on rcgroups. I have already been documenting it on the german rc-network, however considering how long I took to gather the information i needed I want to also post here on an english platform so that other people will have an easier time in the future should they want to build a 1m dlg whilst having little idea of what they are doing.

This is my second dlg project, and also my second non-foamboard build. Last summer i built a rcn09 according to the plans in rc-network from 2009 in around 2,5 weeks, using hm51 airfoils. The first plane ended up pretty heavy ( around 350g) partially because of me building the fuselage positive aswell. Since I still had a blast flying it I want to build another one, and take a litte more time for this build. Since the standard size model wont fit into my car assembled I wanted to try a smaller wingspan.

Whilst wanting to improve quality compared to my first build,I still wanted to keep it a low budget and low effort build. Building a perfect shiny mold is awesome, but just too time consuming. Instead I put my new 3D printer to the test, and printed a mold for the fuselage. I also want to incorporate the 3D printer in other parts throughout the build.

After some research I realized that there is relatively little info about 1m builds compared to the (obviously more common) 1.5m models. I stumbled upon the Aires threads, however since i wanted to wire cut the wings I could not make much use of the CAD files for the aires wing. I have no experience whatsoever regarding airfoils and wing design, so I wanted to keep it as simple as possible. Fortunately I got helped after asking on how I could approach the wing project:

Quote:
Originally Posted by G_T
For quick and dirty design that should fly well, I'd suggest modifying the 1.5m Synergy wing. (...)

For what to do - quick and dirty version - use the average of the "60" and "50" foil for the root airfoil. Move it out a quarter of a meter from the root of the 1.5m Synergy wing design. Use a chord that is proportional to the location between the original 60 and 50 foils. Keep the hingeline straight. That's basically it. I could tweak it a bit from there but that should be rather close.

(...)
Gerald
The attatched files are exactly what Gerald proposed: Simply put, I just chopped 25cm from each synergy wing, and interpolated the airfoils accordingly.
The overall specs ( length, boom length & fins) are based on the aires by RHX138.

The name of the plane is a reference to a little downhill skateboarding company I used to run ( "delta boards " ). I actually have most of the tools used ( vacuum pump etc) from building longboards, so I liked the idea of keeping the delta theme up. The term Δh is used in physics as a variable for a change in height, for anyone unfamiliar.
Last edited by dodo3441; Mar 19, 2019 at 10:38 AM.
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Mar 11, 2019, 06:28 PM
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build progress


Heres how far i am at this point:

Printing the fuselage mold and pressing the first fuselage was successfull. ( Using Hobbyking PLA ) Unfortunately I forgot to place the hatch in the mould, other than that it turned out pretty good. The mould was sanded slightly after printing and treated with mold release.

Layup for first fuselage:
3 x 80g/mē glass in the front
3x 80g/mē unidirectional carbon in the back
some extra reinforcements under the wing, aluminum plates for wing mounting

The fins are just standard, 25g glas finish.
Last edited by dodo3441; Mar 17, 2019 at 09:43 AM.
Mar 11, 2019, 06:31 PM
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eitanro's Avatar
Great work with the 3D printed mold.
I'm surprised that you managed to release the laminate from the mold.
What pressure do you use for the bladder?
Mar 11, 2019, 06:40 PM
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Questions:


Quote:
Originally Posted by eitanro
Great work with the 3D printed mold.
I'm surprised that you managed to release the laminate from the mold.
What pressure do you use for the bladder?
Yeah i was surprised how well it worked. I only sanded it with 240grit or so, and then gave it three coats of the "High-Gloss Release Agent | HP-HGR5" from hp-textiles. No waxing, no polishing etc. Note that I sprayed the mold with some silver paint to better see where I was sanding, and some of the paint actually stuck to the fuselage making the surface look worse than it is. You wont get a high gloss finish like this, but going from CAD to fuselage over the weekend is pretty cool.

Pressure was only 3 bar, I was scared of wrecking my mold . Ill see if I can go higher for the second fuselage.







The wing cores should arrive in a few days, so the first flights are not too far away. However I still have some questions:

1. Horizontal Stabilizer

I am unsure wether I should build a normal elevator, or full flying one.
The weights of the printed pylons are both around 0,95g.

2. Peg

Would you reccomend a normal, or a t-peg ? ( I havent tried building a T peg, but I guess it should be doable with a printed mold)

3. Wing layup

The first wing will be built using 80g/mē glassfibre +-45° since i still have some of that lying around. Basically a low budget practice wing. Do you recon this will be enough by itself or do I need extra reinforcements?

I used the same layup for the 1.5m wing + some rovings as spars and it holds up well. However the synergy is thinner than the hm51 as far as I understand, so im not sure if I need to reinforce the flaperons.
Last edited by dodo3441; Mar 12, 2019 at 08:13 AM.
Mar 12, 2019, 06:38 AM
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cbarnes0061's Avatar
Looks good. For the stab I would say just you a normal elevator. Full flying stab would require absolutely zero slop in you servo and linkages to keep from having flutter during a launch.
Mar 12, 2019, 07:42 AM
I build what I fly.
ibnjmn's Avatar
I love your 3D-printed fuse mold! I have had the same idea, but didn't have the courage to try it. Since I'm also in the process of trying to make a better pod, I'd like to hear more about how you designed the fuse, especially the size and shape of the pod.

I have not tried a full-flying stab yet, but I like the concept. I decided that the standard, hinged design was simpler for myself to execute. Ideally, you would also choose the airfoil of your stab based on whether it will be hinged or full-flying.

For the peg, if you're going for simplicity, then a standard straight peg is the simplest. That's all I have used, so far. If you want to mold a peg, though, that sounds fun, too, and there's some good information about it here on the groups!

I built my ZoneV2 wing last year out of 47gsm fiberglass with doublers at the root and on the flaperons, top and bottom, and unidirectional carbon fiber ribbon spars. It's holding up fine, so far! I think the Synergy wing should be very similar, or even easier, to build than the ZoneV2.

80gsm fabric will turn out a little heavy, but it should still be fine for a practice wing, and should still fly pretty well. Practice is a really good thing, especially when you're not using expensive fabric to learn how not to make mistakes!
Mar 12, 2019, 08:10 AM
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Quote:
Originally Posted by ibnjmn
I love your 3D-printed fuse mold! I have had the same idea, but didn't have the courage to try it. Since I'm also in the process of trying to make a better pod, I'd like to hear more about how you designed the fuse, especially the size and shape of the pod.
Theres not that much to it designwise. I just took pictures of other 1m gliders i could find ( aires, strike, mini fireworks ) and used those as a reference for my design. Having those rough measurements I just made it in a way that i thought looks good and fits my servos.

I also just realized that i forgot to add the cad & print files, editet the first post.
Last edited by dodo3441; Mar 12, 2019 at 08:20 AM.
Mar 12, 2019, 05:02 PM
Aurora Builder
Quote:
Originally Posted by ibnjmn
I love your 3D-printed fuse mold! I have had the same idea, but didn't have the courage to try it. Since I'm also in the process of trying to make a better pod, I'd like to hear more about how you designed the fuse, especially the size and shape of the pod.

I have not tried a full-flying stab yet, but I like the concept. I decided that the standard, hinged design was simpler for myself to execute. Ideally, you would also choose the airfoil of your stab based on whether it will be hinged or full-flying.

For the peg, if you're going for simplicity, then a standard straight peg is the simplest. That's all I have used, so far. If you want to mold a peg, though, that sounds fun, too, and there's some good information about it here on the groups!

I built my ZoneV2 wing last year out of 47gsm fiberglass with doublers at the root and on the flaperons, top and bottom, and unidirectional carbon fiber ribbon spars. It's holding up fine, so far! I think the Synergy wing should be very similar, or even easier, to build than the ZoneV2.

80gsm fabric will turn out a little heavy, but it should still be fine for a practice wing, and should still fly pretty well. Practice is a really good thing, especially when you're not using expensive fabric to learn how not to make mistakes!
Synergy is thinner than Zone-V2 (ZV2). It needs more reinforcements, specifically in the spar and the flaperon (prefaced) than ZV2 to get a reasonably rigid wing.

I too find that fuselage mold quite nice for a quick approach with reasonable quality! The method should also work for a wing mold really; the only problem there is getting a core sorted out, but hollow molding is an option. I also wonder how a geodesick 3D printed wing would work out with some carbon reinforcements in the wing spar and going to a carbon reinforced filament.

I'll keep following along as I get my Ender 3 up to speed. I assume that is the CR-10 in full action?
Mar 12, 2019, 10:14 PM
G_T
G_T
Registered User
Synergy is generally a little thicker than Zone V2. Part of the goal was to make it easier to make. You might be thinking of Synergy-II.

Just a note - as long as your hingeline gap isn't large, don't use a gap seal. It will fly better without one. That is, if your gap looks like what you would expect for a bagged plane, that is good as-is.

Flaperons should always be faced. The difference in torsional stiffness is considerable.

Gerald
Mar 13, 2019, 08:42 AM
Aurora Builder
Yes, I was thinking of Synergy-II.
Mar 13, 2019, 10:41 AM
Bel Prince of Fresh Air
This is fantastic. My friend, Magicmanyyc, did a 1m last year and a big part of the work was the fuse plug and mold. Short circuiting that process is very appealing.

Is there any reason you didn't design in registration bumps/dimples?
Mar 13, 2019, 11:51 AM
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Thread OP
Quote:
Originally Posted by Hill_Smith
Is there any reason you didn't design in registration bumps/dimples?
Most likely because I dont know what they are, care to explain?
Last edited by dodo3441; Mar 13, 2019 at 03:20 PM.
Mar 13, 2019, 11:52 AM
Registered User
Love the 3D printed mold. I've been trying to do something like this too I love your thin wall mould with epoxy filler! Can you tell us more about the bladder? I'll check the thread you reference too.
Mar 13, 2019, 12:00 PM
Flying Low
cbarnes0061's Avatar
Quote:
Originally Posted by dodo3441
Most likely becasue i dont know what they are, care to explain?
I believe he is referring to having alignment pins molded into to it so the mold halves line up the same every time.
Mar 13, 2019, 01:05 PM
Registered User
Quote:
Originally Posted by cbarnes0061
I believe he is referring to having alignment pins molded into to it so the mold halves line up the same every time.
This ^. The other thing I've done with 3d printed molds, is make a hole through both side when they're still in cad. The get some 5mm stainless dowel pins and a 5mm reamer. You can get a tight fit on the pins and they won't stick to the epoxy.


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