Orion-E electric glider build blog

[David E]

Well, here's my first build blog and only my 2nd balsa build, so please bear my inexperience in mind!

 

I'm afraid I don't have any photos from the first assembly steps.

 

Here's the planned electronics set-up, which is complete except for the battery connector. I'm sure I have several of those JST connectors somewhere, but I can't think where! I might switch to Deans as they are easier to make a good connection as I don't have a proper crimp tool. The motor is one of these: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5431&pb=1 as stipulated by the rules of my club's glider duration competition. (as is the 2s 360 mAh Rhino battery)

 

edit: sorry can't get picture upload working on work PC will have to do at home!

Edited By David E on 19/10/2009 12:50:55

Edited By David E on 19/10/2009 13:05:44

Edited By David E on 19/10/2009 13:06:21

[David E]

Right, let's have another try!

 

Here's the planned electronic setup:

 

[David E]

Here is the first assembly photo i have:

 

The spar and ribs go together really nicely as they're very accurately CNC cut. In this picture the 2nd fuselage side is between the building board and the bench, being squished by the clamps while the glue dries on the reinforcing sheet that doubles up the front half.

[David E]

I've now assembled most of the fuselage, put in the snakes and begun the sheeting on both the fuselage and the wing:

 

I am fairly pleased with the finish on the rear end so far...

Although the pre-cut part to cover the top of the rear of the fuselage and support the tailplane ended up a bit narrow. Hopefully shouldn't show up to much once the tailplane is on.

 

I need to do the epoxying still to hold the snakes in place.

 

 

 

Edited By David E on 19/10/2009 20:03:39

[David E]

I haven't done the sheeting on the front part of the fuselage yet as I haven't figured out where I want to mount the servos. I think it will make it easier if I can get fingers to top and bottom while installing the servo rails. I'm expecting to mount them further forward than in the plans because the motor and battery are much lighter than those in the prototype. I'm hoping to minimise ballast as much as possible.

[David E]

One thing that puzzled me was that part of the lower wing sheeting is meant to be joined at the edge of a rib, not over the middle of it, leaving an unsupported join. I've added a couple of tiny balsa bits (and will probably add another at the LE) to make fitting the sheeting neatly easier:

 

 

Getting a suitable prop set-up has proved tricky, finding a spinner with the right combo of shaft size, spinner diameter, and accepting a prop small enough for the motor. The one I've got at the moment is designed for blades with an 8mm root and the blades I have are 5.5mm root. I was thinking of using spacers, but someone's pointed me to a spinner that Puffin models lists that will be perfect if they can get them in stock.

 

Never having used a folding prop before, I was a bit puzzled that the blades can pivot forward about 30 degrees. However, I'm assured this is normal...

 

The motor can't be front-mounted I think, so some re-designing of the motor mount will be necessary, and may lead to a slightly lengthened nose. I may increase the size of the rudder slightly as this will help keep things balanced to side gusts, and I've heard it may improve handling on this model.

 

[Emil Benson]

keep up the good work david

[David E]

Thanks, I'm just off down to the shed now....

[Simon N]

Hi David, 

 

Nice blog so far mate, looks like you are making a good job of the build  ......    

 

Following with interest ... I'm about to start a glider myself soon. Never built (or flown !! ) one before, but it will make a good winter project while I'm finishing my Flair Cub.

 

Seen a lot of different ones on youtube vids, and have decided to build the Carl Goldberg Gentle Lady kit. Supposed to be a nice steady glider, a bit of a floater, but I dont mind that. Also gonna convert it to electric for flat field, so I need to start reading up a bit more on Timbo's electrickery posts ... ( cheers Timbo   )

 

Ordered it last Friday, so waiting on the Postie ....

Keep up the good work mate ....

 

Cheers,

 

Simon. 

Edited By Simon N on 19/10/2009 22:11:48

[David E]

Had a bit of a frustrating evening trying to glue sheeting onto the bottom of the main section of the wing. It just didn't want to stick Resorted to holding the thing against the bench with lots of heavy stuff. Will have to have another go at sticking the sheet down behind the LE tomorrow as I know there's no way it'll have stay stuck.

 

Meanwhile I started on one of the outer wing sections.

 

I decided that I won't fit the leading edge until after doing the sheeting for the outer sections. I think it should be much easier to do the sheeting this way, but I'll have to be very careful to avoid warping.

 

I noticed an error on the plan, it states upper sheeting only on these sections, which is clearly wrong from the rib profile (you can see the gap underneath) and contradicts the instructions. Oh well!

[Simon N]

Hi David,

 

What glue are you using mate to try and stick your lower wing sheeting on ?

 

I've only just built my first wing myself, but I found it much easier to glue on the sheeting with medium Cyno rather than PVA glue or similar. You dont need to mess around trying to pin it down to hold it.

 

I glued it along the length of the spar at the back first, and then when this was dry, worked along a bit at a time on each rib with the Cyno, holding it down as I went. It doesn't take long to grab, and no danger of it lifting back up. Goes on easily once you get the hang of it.

 

Apologies if you already tried this, but if not, worth a shot.

Also, I would think twice about sheeting the outer wing panels before fitting the leading edge, as there will a lot less rigidity to the structure, and more chance of things going pear shaped ....

 

Cheers,

 

Simon. 

[David E]

Simon, thanks for the tips. Guess what, I was using medium CA! Normally I find it does grab nice and fast, but for some reason last night, I put the glue in place, put the sheeting on, held it firmly against the ribs for a while, but whenever I let go, it just sprung back up

 

In the end I resorted to PVA along the edge against the spar and leaving it overnight. Hope the dried CA won't stop it sticking too much. I'll have to go back and do the front edge today, but I suspect the CA may have eventually made it stick in the wrong position The PVA will certainly have stuck to the cling film

 

The reason I'm contemplating doing the sheeting first on the outer panels is that it has been so difficult to get the sheeting to stick to the ribs properly once the LE is in place on the main section. It doesn't like to follow the curve down to the LE properly. I wonder if I glue the top while it's still pinned to the board whether it would work ok?

 

I wonder if part of the problem is that the CNC cut parts, although very accurate, don't have proper sharp internal corners, you get a radius of about 1mm, probably the radius of the cutter. You can just see this in the far right of the above picture. I took a knife to some parts so that they mated better but haven't done this with the top and bottom of the ribs.

 

Cheers,

 

David

Edited By David E on 20/10/2009 08:49:13

Edited By David E on 20/10/2009 09:10:58

[Andy Gates]

I think you will find CA prefers to stick to Cling Film and PVA will lift off easily.

 

I do agree with Simon, the leading edge does need to go on to the ribs before you put the sheet on.

 

What may be easier looking at the frame you are showing in the pictures, is to lay the lower sheeting down on your building board and weigh it into place.

Thinly coat the underside of the lower spar and the underside of the ribs with PVA glue and fit the frame to the under sheet.

Again weigh or pin it into place.

At the same time add the leading edge and weigh, pin or prop it in the correct place.

Leave the assembly to set.

 

Hopefully the under sheeting is long enough to overlap the leading edge.

 

After the assembly is set, remove the parts holding the assembly down.

 

What I would expect to happen is that the sheeting overlaps the leading edge and once both sheeting panels are added and dry, the sheeting is sanded to fair into the leading edge.

 

Another question, how are the panels joined? I assume there is a brace to be fitted so it may be better to check the fit and place the brace prior to fitting the upper sheet, which may mean propping the inner panel up to allow the outer panel to sit flat on your building board to be able to fit the upper sheeting on the outer panels.

Edited By Andy Gates on 20/10/2009 19:09:45

[David E]

You're right, it peeled right off once dry. It felt awfully gooey against it to begin with though!

 

I found a method that worked better for the other lower sheeting section - I glued the front into the corner first and let it set. I then put glue on as much of the ribs as I could reach and held it down at the back by placing the wing on the bench and weighing down. Here's a pic while the first stage was drying:

 

I've now completed the middle section of the wing I think:

Progress has been slow this week due to generally being too busy The weekend won't be much better either. Hopefully I can get some more done next week.

[Big Bandit]

David,

 

Looking good so far, I've had the kit for about 2 years and still not got around to building it. Your efforts are spurring me on a bit.

 

Cheers,

 

Chris.

[David E]

Thanks Chris. Yeah, i've read in lots of places that it's a great flier, even with little lift about, so why not make use of the dark hours now the clocks have gone back?

[David E]

Ok, I made a little more progress this morning, mainly putting the LE on the left outer wing panel, which wasn't as straightforward as it should have been!

The front of all the ribs lined up exactly except for the one where the wing section joins to the centre one. Now this gets me wondering what will happen when I mate the two wing sections together. It looks like the thick rib on the right of the picture above has somehow ended up a bit short at the back (spar to TE) but the right length at the front. Perhaps I sanded it a little to heavily at the TE while putting a sharp corner into it to mate to the TE properly. Anyway, this seems to have introduced a tiny bend into the main spar (the TE is very stiff in this dimension due to shape.)

 

The only solution I can find to this is to sand down the front of the rest of the ribs until everything lines up, and then sand out the misalignment between the wing sections at the trailing edge once assembled. it's only a couple of mm.

 

While looking at this, however, I realised that the second glue joint I made, way back at the start, was wrong.

 

Step 2 suggested to me at the time that the dihedral brace was meant to be aligned with the bottom of the spar. Turns out it would be much better if it had been spaced 1.5mm up from the bottom. That would have saved having to cut a step for it in the bottom wing panel, as visible in the far left of this earlier photo, before I had glued the sheeting down:

 

This photo shows that the rib is cut with plenty of room for spacing it up from the bottom of the spar:

 

This would have made the wing sheeting a lot simpler to do, and probably resulted in a slightly stronger wing. Oh well. I chalk that up as a minor instruction boo-boo.

 

[David E]

Actually, the first photo in my post dated 23/10/2009 18:44:34 shows the cut out in the skin for the dihedral brace much more clearly!

[Norman Wyatt]

David

 

What a stroke of luck.  Bought myself an Orion yesterday and found your build this morning.  Never built anything before, so your build is going to be very useful.

 

Task for this morning is to clear the garage and make up a workstation.

 

Norman.

[David E]

Glad it's of use

 

Progress is still slow due to lack of time, but I got some more done at the end of last week. I decided to glue one of the outer wing panels on before doing any of the sheeting, as it allowed me to clamp it better while it was drying, specifically, it allowed me to clamp the dihedral brace to the spar better. The instructions say to pack the dihedral brace with scrap wood, but it's such a small angle, and as it's quite flexible in that dimension, I'm not sure it's worth it really.

 

 I glued the other (half sheeted) outer wing panel on last night too.

 

 

Note to self: must sort out some shelves so I can tidy up the workshop!!

 

It's a bit cold in the workshop, so I'm a bit concerned about how well the araldite on the wing joins will be setting. Will leave them for 48 hours just in case.

[David E]

Oh, btw, I worked out what the problem that caused the misaligned ribs at the LE was. The slot for the main spar in the thick rib needed sanding slightly on the rear edge. I did this with the other side and it lined up perfectly.

[Norman Wyatt]

David.

 

If you get 5 minutes, could you list the electrical components that you show in your photograph.  I followed the link and the motor seems very cheap.

 

Having prepped the garage I will be making a start by the weekend........

 

Many thanks.

 

Norman

[David E]

 

Sure, from the top right going clockwise:

 

- 2x Turnigy TG9 servos

- Spektrum AR500 receiver

- Motor as per first post

- Turnigy Plush 10A ESC

- Rhino 260mAh 2S battery

The prop is a Graupner Cam 6x3 folder. I'm still trying to sort out a spinner that fits properly. I'm hoping to get one of these when they're in stock.

 

Be warned that this may be a far-from ideal combo! I am pretty new to all this myself and I haven't tested it yet. The motor is not perfect for the airframe but I didn't have a choice about that! The connectors I got (top right) turned out to be a bit small for the motor leads so I need to find some different ones I'm also wondering whether better quality servos would be a good idea. A bigger battery would be good if that wasn't fixed by the competition rules also.

[Andy Gates]

That sort of looks OK to me at first glance although a 10A ESC may be a little close but tests prior to flight should prove it.

 

Servos should be fine, they are not going to carry much of a load in that machine or any other thermal glider.

 

Bigger battery would weigh more taking the edge off of flight performance, so the small battery should be fine.

 

Just my opinion of course.

[David E]

Thanks Andy. Do you think I'd be better off using these 5.1x3.1 blades? I don't imagine the change from 3 to 3.1 in pitch would be significant? I want to keep the current under 7A as I'm looking for maximum efficiency from the motor not maximum power. Another option might be these 4.7x2.4 blades. I suppose I'm not looking for a hugely high speed when climbing, so the lower pitch might be ok, but wonder if that might be a bit under-propped being under the recommended size in both pitch and diameter. Would that cause any problems or reduce efficiency?

 

I suppose as I'm using a larger spinner than the blades are probably designed for, I'll have a larger effective diameter?