|Mar 12, 2014, 07:23 PM|
Balsafactory.com 1M balsa DLG build
I've long been wanting to get on the DLG craze but could never really afford the big splash on a proper model. Last May I came across some postings done by balsafactory.com here in RCG showing of a cheap 1m DLG balsa kit at a very reasonable $30.
After a few emails going back and forth I had placed an order for one of these kits. Turned out shipping was more than the kit itself ;-). Kit arrived and got put on the todo list with so many other projects, and stayed there till about last week as the flying season is about to start again after a long, wet and windy winter.
The nice lady who took my order also sent me updates along the way on issues that they had discovered since the release of the kit. Luckily it was only two minor issues:
The kit contains nearly all you need apart from glue, covering and electronics. A 1:2 size plan and an A3 instruction sheet with pictures and some descriptions shows you how to go about building this kit. The instruction sheet could be better and the text is a typical translation from chinese to english where half of the info seems to be lost in translation. But if one has a bit of kit bashing experience its' not exactly rocket science to put this together.
The model should hopefully look similar to this picture once the kit has been glued together. If you end up with a duck instead you used the wrong parts
The kit content with plan. Note the white bits in the plastic bag which is the included fiberglass sheets. Would have been better with some carbon fiber..
The right wing has been started. The wing is built very traditionally starting with the wing ribs and the TE. The wing ribs have support tabs which makes it easy to get a straight looking wing. The carbon strip is glued to the front bottom sheeting. This process was a bit tricky as it wasn't really possible to glue the carbon before slotting the sheet in. I ended up slotting both the sheet and the carbon strip in place and then glue using ZAP. I lifted the carbon strip from the sheet using the tip of a small flat screwdriver to be able to get the glue to flow between the two parts.
Here one can see the two carbon fiber strips which follows the full length of the wing panel and is glued to both the bottom and top sheeting (top sheeting to follow). This should make the wing strong enough I hope. Not so sure about the wing joining area, but that's for another day...
I'll post some more info of the build again tomorrow time permitting. Now its time for some shut eye.
|Mar 13, 2014, 03:24 AM|
I believe they are. Not sure why they don't have them on their website at www.balsafactory.com, but drop mildred (at) balsafactory (dot) com an email and ask. She sent me some pictures of their kits about two weeks ago, so I would think they still sell them.
Update: I see they sell them on http://balsa.en.alibaba.com/product/...sa_glider.html
|Mar 13, 2014, 07:14 PM|
Left wing has been started. Here one can easily see the support tabs on th wing ribs as well as the slow in which one drops the lower front sheeting into. This makes it very easy to get a clean and straight wing.
Before gluing the bottom sheeting I also dropped in the spar to make sure the spacing of each wing rib was correct.
When doing the second wing panel and before gluing the bottom sheeting to the wing ribs I made sure the angle of innermost ribs matched up with the already glued left wing panel.
These are the wing joiners. Made up of 2 sets of 4 2mm plywood parts. They're on the smallish side so time will tell if they can provide enough strength.
At the tip of the right wing panel there is a full balsa block. I decided to make sure the top and bottom carbon strips that is glued to the spar also entered as much as possible into the balsa block which will hold the throwing peg.
Right wing tip glued in place....
Two wing panels getting near completion. Next step is to add some carbon sheets to the right wing tip.
|Mar 13, 2014, 07:18 PM|
As the kit only contained fiberglass sheets to strengthen the wing tips I ended up using some of my own stock of carbon sheeting. It's not very thick but a quick comparison between a balsa piece with the fiberglass sheeting and my own carbon sheeting did show a slight stiffer result with the carbon, so that's what I ended up using.
Here one can also see the small area of the wing joiners...
|Mar 15, 2014, 10:38 AM|
Started on the fuselage. The fuse sides are blasa with plywood support. It is marked out where each part goes so you cant' really go wrong. (Sorry about the lack of focus on this picture)
Next step was to glue up the wing mounting formers. Two blind nuts are pressed and glued into two layers of plywood which is the fitted in the slot between the formers.
Both fuselage sides are glued on. I have left out the front former and servo tray to be glued in later in order to be able to insert the tail boom.
The wing will be resting on two plywood parts which are glued into the recess in the fuselage formers. A bit of sanding was needed to get a good fit. Once glued in place the bolt hole for the blind nuts was re-drilled.
|Mar 15, 2014, 11:13 AM|
Wing panels glued together.
With wings balanced and a bit of catbon added to the wing joint area the total wight is currently 48.9 grams / 1.7 oz. Once convering has been added I guess it will add another 10-15 grams to the total wight ending up at around 65 grams /2.2 oz or thereabouts.
Getting the holes drilled for the wing bolts is always interesting. This time I first drilled the front hole. Once that was complete I made a small tap of a 3mm bolt which I then fitted to the read mount and made sure it only came up above the wing seating ever so slightly. Then it was just a mapper of mounting the wing using the front bolt, measure the correct distance from the tail boom to each wing tip and press the rear of the wing down onto the tap. Worked like a charm.
The kit contained two lookalike carbon sheets to be used for the wing center. However, these two bits of plastic is only useful for decoration and will add nothing but weight to the model. I ended up using my own stock of carbon sheets to do the wing center.
The canopy for the fuselage is made up of three bits of balsa. As can be seen from this picture a small sheet of balsa is to be glued between the wing seating and the canopy lid. I might just extend the canopy to cover this bit as well to make it a bit easier to get to the rear servos mounting lug.
|Mar 24, 2014, 03:10 PM|
Progress has be a bit slow the last week or so, but then I've never been one to rush things.
The fuselage boom fairings have been glued in place. I managed to forget skip this step as I glued the horizontal stab support to the boom first which is a bit stupid. Luckily it's only basla so after splitting the fairing pieces in two it was a quick job to glue then in place. A bit of sanding is needed, but using a dremel will speed the process immensely.
In the kit, the horizontal stab support consists of 4 pieces of balsa wood and two pieces of plywood, which according to the plans are to be glued together with each of the plywood pieces at top and bottom. I left one of the balsa and and plywood pieces out as it looked like the tail would just be a bit too high and too fragile. 3 levels of 5 mm balsa should be enough. I have later also strengthened the area by adding a piece of glass fiber cloth and epoxy . Before gluing ,the shape of the piece to be glued to the boom was sanded by wrapping a bit of sandpaper around the boom.
The boom also had to be slotted to fit the vertical stab. An easy job with the dremel.
Nose cone consists of 6 pieces of 5mm balsa of which the two middle pieces are somewhat hollowed out.
Wing has finally been covered using SoLite yellow transparent film. Weight before covering was 46.9 grams / 1.65 oz . Once complete this part now weights 54.5 grams / 1.9 oz. Just need to glue in the throwing peg and its done.
|Mar 24, 2014, 03:35 PM|
To strengthen the vertical stab somewhat I added a bit of 0.5mm flat carbon strip on both sides of the area which slots into the boom. I also glued a strip of fiberglass to the lower front part of the vertical stab to protect it against "hard landings".
Horizontal stab, elevator and rudders have been covered. The vertical stab has also since got its covering done.
Stabs have been glued and secured. Horizontal stab is secured by two screws into the ply/balsa support block.
Now comes the difficult part which is why I have also left the bottom sheeting for the fuselage to be done later. How should I do the pushrods on this model. The kit comes with 0.39mm / 0.0153" piano wire and sleeve. However the sleeve is very flimsy and will have to be supported every few inches. Another complicating factor is that there is no easy way to route the sleeve outside of fuselage due to the tight area where the boom is glued to the fuselage. I'm leaning towards trying to fit the sleeve for rudder/elevator into the boom and try and secure it by making a couple of support that will fit inside the boom every few inches. I won't be easy but I can't see it being done any other way. Anyone got any other suggestions on how I should do this?
|Mar 30, 2014, 03:24 PM|
Managed to get some more work done. The build is now nearly completed.
After a bit for searching around on RCG I came across this thread (http://www.rcgroups.com/forums/showthread.php?t=1374442)where magnets was used to help with keeping the pushrod sleeves to the inside of the boom while the glue was curing. Inside the fuselage I supported the sleeves with two pieces of depron.
Once the pushrod dilemma was resolved I fixed the servos and made the connector ends for the pushrods. At the moment I have only done Z-bend at both ends of the pushrod as a temporary fix. I will be ordering some T-Rex 250 ball links and balls to get an adjustable connector at the elevator and rudder end. But to get it in the air the Z-bends will do,even if there is a bit of slop in the linkage.
Once the fuselage was sanded down and covered, elevator and rudder installed the weight of the model ended up at 137.4 gram / 4.83 oz with the servos installed. I didn't weigh the servos but they're both BMS-306BB ones and according to their specs weight around 7gram each making the model with 123.4 grams / 4.35 oz.
I'll be using an FrSky D4R-II receiver with a 360mAh 2S LiPo pack to power the RX. But since servos are not 6+ volt servos I either have to reduce the voltage to the receiver or to the servos. I ended up ordering two regulators which are supposed to be used between RX and servo. http://www.hyperflight.co.uk/product...=mks-1-5a-sbec. With these installed I will be able to get an accurate reading of the LiPo pack via the FrSky telemetry.
I could also have gone for a 1S pack but that would have left me unable to use a openXvario which requires at least 5v to work.
Hopefully there will be room to fit all the electronics in the bay. There is quite a lot of space available dor a DLG so it should hopefully be ok. :-)
So now I just have to wait for the servo regulators to arrive from the UK before I can get a test flight - which I hope will happen this coming week since the weather is on the "superb" side at the moment. I also have to figure out the CG as the included plans/instructions doesn't mention anything about it.
|Mar 30, 2014, 11:35 PM|
It may be just the camera angle, but the wing appears to have little or no dihedral.
Rudder/Elevator planes without ailerons require quite a bit of dihedral to make a turn.
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