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RCM&E at 60: Kakadu, the first free plan

Plan from vol. 1, issue 1, p47

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Dad_flyer11/04/2020 18:10:44
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315 photos

I noticed too late, but not too much too late. The fuselage side cut out for the lower wing is totally the wrong shape. I had cut it out from one side, but I still had the piece to glue back in. blush

The plan is very fuzzy, so I had to try to copy a rib from the built wing to make the correct template.

img_20200411_170141745~3.jpg

That seemed to fit when cut out.

The incidences are:

Lower wing and horizontal stabiliser: 0 deg

Top wing +4.5 deg . That seems a lot?

Down thrust 2 deg.

Right thrust is unclear. Depending which line I look at it is 1 degree or 2.5 degrees. Try 1.5 degrees?

Dad_flyer12/04/2020 12:01:07
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307 forum posts
315 photos

The nose has doublers and triplers.

img_20200412_114639691~2.jpg

I did not put slots in the main doublers for the main formers. Too many cuts on both sides. The wing saddle tripler and the lower formers have the tabs, which is useful in putting the cabin insides together.

img_20200412_114915113_hdr~2.jpg

I cut the formers with the grain the wrong way, so they have 1/6" stiffeners.

I think the battery will be able to slide forward under the motor, so there is an opening in S1 for that.

Bob Cotsford12/04/2020 14:31:54
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8581 forum posts
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4.5 degrees does sound a lot for the top wing. Are you measuring the incidence from the bottom line of the ribs or by the max chord line through the centre of the leading edge radius? If the latter then the real incidence is even more, and the lower wing -ve. I've only seen a difference of maybe 2 degrees on any bipe I've owned.

Dad_flyer12/04/2020 14:44:16
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307 forum posts
315 photos

The angles are measured from the flat bottom of the wings. I have just double checked on the RCM&E version of the plan.

This is designed as only single channel, and I am not putting on elevators. Rudder and throttle only. Does this incidence make sense for basically guided free-flight?

Bob Cotsford12/04/2020 20:34:30
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8581 forum posts
477 photos

I guess it does, my Eros certainly had a lot of longitudinal dihedral and needed the wing t/e raising a good 1/4" to get it to penetrate instead of climbing. It still needed lots of down elevator with the throttle open and would have benefited from 1/8" under the tailplane l/e too. I think the message here is "don't overpower it"!

Dad_flyer12/04/2020 20:45:39
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307 forum posts
315 photos

Thank you. I am still thinking about the power. The plan says 0.6 to 0.8cc. The outline on the plan is a diesel, so the top end of that range is the PAW 049, which is 100W. I shall probably put in a relatively large motor as the little ones look wrong and I think I shall need the nose weight. Then prop for 75-85W maybe.

I shall also need glide tests.

I had not thought of that incidence as 'longitudinal dihedral'.

Edited By Dad_flyer on 12/04/2020 20:46:33

Edited By Dad_flyer on 12/04/2020 20:46:51

Dad_flyer13/04/2020 12:13:01
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307 forum posts
315 photos

Joining the internal structure to the first side. Beginning to get somewhere now. I think it would have been easier if I had re-drawn the plan with sharp lines before starting. Taking everything off the one cut rib and the first cut fuselage side has taken more thought and more time.

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I remembered to put in holes for the wires and two battery positions before joining the formers.

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Dad_flyer14/04/2020 21:53:40
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307 forum posts
315 photos

Second side joined on and seems to be straight. Tail peg in and supported by scraps, then the top and bottom spreaders.

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img_20200414_110828371~2.jpg

Dad_flyer25/04/2020 10:35:59
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307 forum posts
315 photos

It has been a while since I posted. I put the rear top sheeting on. The plan says longitudinal grain, which is unusual. Probably it would be fine as there are the internal braces, but I did cross grain anyway. The last part will need to be length ways because it needs to bend into the former for the dihedral v.

img_20200425_102222147~2.jpg

This has had a couple if coats of thinned dope and sanding. Next I shall put tissue on the sides, as that is easier without the pegs for the wing bands. Then the pegs go in and I can finish the sheeting.

Dad_flyer25/04/2020 10:53:36
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307 forum posts
315 photos

I also had some off cuts of really nice soft balsa and messed about with bending. 1/16" making a chair (or air intake if you put it the other way round), 3/32" and 1/8" bent round a pencil.

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I also got 1/16" to go round a small screwdriver, so made a cover for the push rod exit.

img_20200425_102624647~2.jpg

Dad_flyer29/04/2020 19:55:44
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307 forum posts
315 photos

Slow progress here, I have jobs on five models going on. Put in the last piece of the top sheet.

img_20200429_194530996~2.jpg

Looks nice faired into the wing dihedral like that, but I think it also means that there is no locating surface for the wing position. I shall see how it feels with the wing covered. I can always add something under the wing to slot into the fuselage.

I planned a blue and white tissue finish. Of course the white has very little colour depth. In the above photo the sides are covered, the top is not. Are there any cunning ways to get it a bit more white without going full hog on paint?

Dad_flyer30/04/2020 17:48:15
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307 forum posts
315 photos

Bottom done as well now.

img_20200430_085943946~2.jpg

Dad_flyer02/05/2020 21:11:27
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307 forum posts
315 photos

I don't like making wire undercarriages. Well this is only the second, but bending correct angles in two planes is confusing and frustrating. A jig helps.

img_20200502_201505704~2.jpg

Dispite, or maybe because of, my dislike of doing it, I am inordinately proud of the end result.

img_20200502_210111601~2.jpg

Wheels from SLEC.

Geoff S02/05/2020 22:13:15
3665 forum posts
26 photos

I find the actual soldering quite easy (well, I've been doing it on and off for about 70 years ) but getting the bends in the right place and allowing for wire thickness etc is, as you say quite tricky. You seem to have ended up with a more than satisfactory result anyway thumbs up

Not my sort of model but there's a lot of satisfaction in creating a working model from a pile of wood rather than a kit as I've rediscovered these last 2 weeks.

Geoff

Dad_flyer02/05/2020 22:20:46
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307 forum posts
315 photos

It is not the model I was wanting to build either. It was supposed to be Miss Deeds next, and I did not want a biplane, or a small plane. But then the anniversary came round and I wondered what plans they had at the beginning. I found the one from the first issue and then there was not really a choice but to build it. I do like vintage, so it does have that smiley. And the more different things I attempt, the more I learn.

Dad_flyer08/05/2020 11:44:46
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307 forum posts
315 photos

The plan has a lower cowl, with the upper part open for an upright engine. With a round electric motor I have made one more change than I was going to allow myself, and the cowl will go all the way round. Carefully removed the step from the sides with a nice sharp scalpel.

img_20200508_102942718~2.jpg

Both sides done, and the hatch in place. I still need to finish the hatch sides flush.

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The cowl will be 1/8" curved all the way round. I hope teeth 2.

Dad_flyer10/05/2020 16:33:12
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307 forum posts
315 photos

I did firewall S1 in balsa as the actual motor mount needs to be further forward. Laminated 1/8" balsa and ply to hold 3mm T nuts. Side pieces set the 2deg down thrust and 1.5deg right thrust.

img_20200510_162127673.jpg

The battery slips in as planned (just). Three possible positions to help with the CG, this is the middle position, C.

img_20200510_162408836~2.jpg

B might not be possible (won't go under the T nuts). However a diagonal version of B will, if needed.

Dad_flyer10/05/2020 20:35:37
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307 forum posts
315 photos

Made a 6" wide piece of 1/8 soft. Wetted and wrapped around for the cowl. The pegs for wing bands come in handy teeth 2.

img_20200510_202733182~2.jpg

I hope I can work out how to cut a big circle in after for the motor. I thought it would be easier to cut when flat, but might then not bend well. I can always do another if this does not work.

Dad_flyer17/05/2020 17:40:06
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307 forum posts
315 photos

Biting the bullet and cutting out the rear deck for the tail. I had put in pin marks from the plan when cutting out the sides.

img_20200517_170551000~3.jpg

Join the dots, and put in a second line at 1/8".

img_20200517_171721437~2.jpg

Then I cut out half way between. Lastly trimmed to the lower mark on the sides.

img_20200517_172856132~2.jpg

The pin marks are clearly there on both sides, so if things were cut straight and joined straight, this should be straight....

Time to check and sand.

Dad_flyer17/05/2020 17:49:25
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307 forum posts
315 photos

As far as I can tell, it is level. laugh.

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