SE5a - dogfight double

[Dad_flyer]

Well, Dad_flyer has not yet learnt enough to be able to fly one, but Child_nonflyer likes the look of it. It will live in Child_nonflyer's room.
So, it is build time with a cast iron "but it's not for me", and no storage implications. What is not to like? It will fly, just not yet by me.
I have finally selected a brushless setup that I think will do for a replacement of the 400 setup of the plan, and Christmas brought me a bundle of balsa, so let's get started.

Edited By Dad_flyer on 30/12/2018 15:32:12

[Dad_flyer]

Original prop recommendation is 8x6 APC-E. That is the small end of scale diameter, so might go to 9" if ground clearance is ok - the motor is rather low kv.
Motor planned is Airmax 2826 1000kv on 3s. 18A max. That will go together all being well.
I had to design up a mount to fit and put the prop in the right place.

Fuselage coming together. Plan suggests opening outformer (4) like (5), but that is a square hole, leaving the former thin at the corners. Instead I used the rounded opening from (14)

This is the motor mount, just slotted together for now. Looks ok, but will it fit? Former (2) is opened out as I think the lighter motor and battery than the design will mean that the battery needs to go further forward. The plan warns it may be tail heavy anyway.

Also, the prop shaft is short, so the front radiator (16) needs a depression in the back. Used two 1/8" instead of a 1/4" to give the big hole at the back and less at the front. Also gives something behind to hold the louvres with.

[Dad_flyer]

Rolled decking now on and cowl started.

The front panel is not glued yet, just in for looks!

[Dad_flyer]

Cockpit cutout made and rear deck fitted but not shaped.

The pilot seems to be happy with it. I shall need to work out a removable deck for him to sit on soon, that is the battery access.

I did not like the idea of fitting the cockpit sides (11) to the rolled decking, so I made the rolled decking all the way back to the rear of the cockpit and cut the cockpit afterwards.

[Dad_flyer]

Motor mount glued in. Had to be pushed a little to the left as the right thrust angle was an afterthought and I had not allowed for the amount that this moved the spinner.

Everything fits and the spinner is central.

Put in a couple of extra air holes behind where the louvres will be.

Very much looking the part now. 30 wing ribs also cut to shape.

[Former Member]

[This posting has been removed]

[Dad_flyer]

Thank you STF.

[Dad_flyer]

Looking at photos I seem to have a choice of brown or green. Chosen green, so now there are 30+ little bits of ply to paint.

I'm not putting off clearing space to do the wings, honest.

[Dad_flyer]

In the RCM&E build article TN poses is this 'sad' or worth it?

Child_nonflier likes it, so I think it is worth it, even though it means the model still has no wings.

[Chris Walby]

Watching with interest and keep up the good work

[Ron Gray]

Defo worth it!

[Dad_flyer]

Wings today. Not very picturesque so no photo.

[Geoff S]

I tend to do wings first because they're a bit samey ( ie not very picturesque ) or usually very interesting so I get them out of the way whilst I'm still enthusiastic. I find the fuselage far more interesting because they're all different and, if it's an electric conversion as a lot of mine are, there's a bit of minor design work to do for battery access etc.

I like SE5a WW1 types

btw this will probably fly in a scale-like manner on much less than the oft-quoted 100w/lb. Certainly 80w/lb and probably only 60 w/lb but you have plenty of scope to adjust that by prop selection.

Geoff

[Dad_flyer]

I'm following the order of the build article. This is my second balsa build, so still feeling my way!

For power, it was designed for a permax 400 motor with gearbox. From what I can find a 400 weighs 70g and is specified at 7A at 7.2V. However in this and other plans they are run at 9.6V. I can't find any mention of the current draw then.

[Dad_flyer]

Slow progress. Cut out the tail parts and joined the sheet for the wing top sheet. The build log says 4" sheet needs 25mm added (nice mixed units 😃. Measuring the plan it is more like 1 1/4", which is a third of a 4" sheet.

The little slots to fit the spars took an age to make. I think I need a Permagrit slotter...

12 to make, 6 left hand, six right hand. Then also need to put them in the right place. I'm not sure I like making biplanes, and I have not even got to the point of fitting the wings and struts.

I made all the ribs the same and cut back the short ones over the plan.

[Dad_flyer]

Wings nearly done. They are very small, only 27" span in total and the solid block tips are 2" each side.

With the ribs and strut sockets all done, next is to put the 1/8" sheet over the top, whilst the frame is still pinned square on the board. How do you get it off afterwards with the pins now covered? My board is also not that flat, so I wanted to use some flat glass. My first solution was to tape the plan to the glass and tape bits of scrap to push/hold the frame in the right place, and some tape over the spar. This worked OK but s bit of a faff to set up.

Finally I shall need to trim the bottom left corner of the sheet. You can see here that even with 4" sheet plus 1 1/4" the ribs are still slightly longer than the sheet.

My second method is quicker, stick the frame to the plan with glue stick. I use that to hold the plan to balsa when cutting out pieces. It holds well enough and I can release the whole paper from the glass, then peel it from the frame.

I used thick cysno to hold the leading edge quickly, then superphatic to give more time to curve the sheet over. It also runs well along the ribs to get in under the sheet.

[Dad_flyer]

Time to make the covering decision:
TN used Easycoat in the RCM&E build article, but says it is a bit heavy at the tail. Suggests Litespan, or tissue and dope. I have access to all three.
Easycoat: Tough, but heavier. Also I need to work out how to paint it for most parts. For the wing underside it needs to be white, and it is an open structure, so the strength will be useful.
Litespan: Lighter, and my LMS has it on the web site. Local is 1hr drive...
Tissue: lightest, easiest to paint. Is the strength needed on the solid fuselage and tail?

Any suggestions?

[Former Member]

[This posting has been removed]

[Wilco Wingco]

Has anybody built/flown one of these with an OS 10 as stated in the mag?. How about a Cox .80 or a Mills 75 ?

[Dad_flyer]

I have not found any other flying notes on forums for electric or ic builds. The photos in the build article have the OS10 fitting nicely. I looked it up to gauge the power and balance point for my electric setup. It comes out at about the same weight I think. The power, 0.27hp, seems a lot for a 24oz WW1 biplane when compared to electric watts/pound. But I do not have ic experience.

[Dad_flyer]

Very little progress this week. Strut holes cut in lower wings. Wing tips blocked up, and one shaped.

Blocked up, but my 12mm balsa is actually 9mm, so needed an extra bit on top.

Rough shape with a razor plane.

One tip shaped. Corners will be rounded a little in the end.

[Dad_flyer]

Little time to progress recently, and I have been trying out finishing methods. Tissue and dope for tail and fuse, Easycoat for wings, which are open underneath. I have not done iron on before. Test pieces are now ok, so on to the real thing next session.

What servo torque do I need? the parts are, so far, heading for a flying weight which will be under the design weight of 24oz/680g. 9g plastic gear 1kg-cm will be plenty? Will 5g servos at 0.6kg-cm be big enough? The smaller servos would allow a full depth cockpit for an alternative pilot who fancies a go.

[Dad_flyer]

Sanding sealer done all over. Some of the tissue done, but not had much good weather to do that outside. The article in this month's RCM&E was useful for techniques of covering solid areas.

More time spent on the film covering, but I am still very slow, so not much to show for it.

I have a job lot of cheap yellow Easycoat that was on offer. It will all be painted.

There was a small twist in the wing, I had re-glued the leading edge to the ribs when I saw it was not quite stuck down, after taking it from the board. Not a great idea. Luckily I saw a method somewhere of holding it twisted back past straight and re-shrinking the open underside. This seems to have worked. I shall keep an eye on it to see if it slips back before I fix the wings.

[Marc ROCHE]

nice plane!

What kind of Lipo and ESC do you use?

Edited By Marc ROCHE on 08/05/2019 08:54:08

Edited By Marc ROCHE on 08/05/2019 09:03:03

[Dad_flyer]

The build has stalled rather with the twisted wing issue, and work. The plan is 3s Lipo. A 2200mAh will be overkill, but the weight should be ok. If possible I am trying to avoid specially getting smaller Lipos just for this model, but we shall see how the weight goes.