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Ian Jones' IC powered and Slope Tucanos


Ian Jones
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Quite a lot of progress now, after a lot of head scratching. The thing is I've got some notes and ideas in my head but all the same I'm pretty much making it up as I go along using the plans as a guide. The plans being for electric power and my models being slope and IC there's quite a few differences nerd.

Last time out I had the basic fuselage and wing for the sloper plus the wing for the IC model and so now it's case moving on to the IC fuselage and things get quite complicated! The main issue is regarding F2 which becomes the engine bulkhead and will need preparing for the engine mount, nose leg, steering and throttle snake. In addition there's the question of where to position it and on top of that it's all a tight fit. I had realised quite early on that it will have to have a wider nose than on the plan, but how much disgust?

Well this is how it went. I made a cardboard template to help with getting the side thrust - using the pencil line as a base I then marked out a second line at 87 degrees to the base line then cut along the second line. I did it this way because the protractor just didn't touch in the right places and this way was as absolute doddle:

sidethrust template.jpg


I used a balsa copy of F2 to test where I would have to position the engine mount to get the necessary side thrust and have the prop shaft on the centre line. It just about made it, not going to get a very pointy nose though!

justfits.jpg

 

Time to move on to F2/bulkhead proper then. Well I had some 1/8" ply and some 1/16" ply and neither seemed thick enough on their own, so I decided to use both:

firewallf2parts.jpg

 

Having plied my plywood I marked the propeller centre line on F2/Bulkhead so that I would know vertically where the engine mount should go:

bulkheadenginecentreline.jpg

 

Having got the engine mount in the right place I then knew where to drill the hole for the fuel tubes and all this rather conveniently just left enough room for the noseleg and steering.

justroomforsteeringtoo.jpg

 

The addition of a steering arm means that the engine now has to be fitted further along the engine mount than I had planned for so that also meant a rethink on the position of F2/bulkhead. The engine will be fitted inverted but laying it on the plan like this allowed me to position the proper driver in the right place which then indicated where F2/bulkhead should go. As that turns out just forward of the original position I should be able to pull in the nose more easily and perhaps get a more realistic shape:

engineonmount positionf2.jpg

 

I then had to mark out the side thrust again and dry fit it all to check that it would all work out. It will.... I think smile owink 2

propposition f2position.jpg

 

Then all of a sudden the production line looked more productive with both models now starting to reach a similar stage:

ic fus taking shape.jpg

 

Edited By Ian Jones on 14/05/2013 00:42:00

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Next job was an oversize F1 which will end up as the front of the cowl:

ic formerplan.jpg

 

Again I modified my plan here and made an even larger hole in F1 for the prop drive to exit. I knew I'd use that hole saw one day!

holesaw.jpg

 

F1 !

ic f1.jpg

 

There's more, but it's late so the next update will have to wait a day or too. Even though I'm running late in the mass build I hope that all my ramblings are of some use to someone.

 

Edited By Ian Jones on 14/05/2013 00:42:58

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Hi Ian

The only problem with going wider is that the spinner will also need to be a bigger diameter. I have a 9x5 prop on my 21 sized Tuc. the full sized spinner looks rather large for the prop... I sacrificied the swoopy curves (which would be hidden by the silencer anyway) and kept the same width as the original design.

Bring it along tonight..

Martyn

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I would have brought it to the he social but it would have got wet in the rain!

I have pulled the nose in a little but the spinner is going to be an issue though, there isn't a lot of choice that I can find for 3 bladed props. I do have a 3 blade spinner I can borrow from my Scorpion Twin so I have that to fall back on if I have to but I one the right size would be better. I hope Barntormers will be able to sort one out for me if not I think I phone call to Webbies will follow.

Ian

Edited By Ian Jones on 14/05/2013 22:38:53

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I have a similar issue at the front end. In the end I've gone for the 2" spinner as it matches the line of the nose really well - but I expect the prop may look a bit small in it. But hey - who's going to notice when its going passed them at 40mph and doing 10,000rpm! smile d

BEB

Edited By Biggles' Elder Brother - Moderator on 14/05/2013 23:12:59

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I can't really go any further without making some provision for the control of the rudder and elevator. I like snakes. They can curve to suit the connection route from the servo arm to the control surface horn and with outer sleeve secured can give a slop free setup. There's a good number of snakes around and I've gone for these Sullivan snakes - a bit heavy duty but they will work!

snake.jpg

I worked out that the rear exit holes need to be 1" below the tailplane and 1/2" behind the tailplane leading edge to provide for alignment with the control horns and so made holes on each side of the fuselage at this position. In this situation I prefer to hold and twist the drill bit in my fingers for ultimate control:

snakeexitholemaking.jpg

Doh, we all make mistakes! The snakes will travel through the fuselage, crossing over as they do so means they can't both be at the same height where they enter the fuselage at the tail end. This little slip is easily fixed bye squaring off the drill hole and then inserting a balsa plug fixed in thin cyano.:

weallmakemistakes.jpg

After some filing with diamond files I the exit holes are shaped to allow the snakes to align correctly. I'm not going to fix them in just yet but I can test for free movement in all possible servos locations. Why well I haven't decided where the servos are going yet - I will do that when the model has more work done on it and I can get a better idea how the CG balance is working out:

snakespositioned.jpg

Since I am now confident I can fit the snakes later I can return to the production line and fit the top sheeting. I've started roughly shaping the tops and also moved on to the canopy floor. The floor will be fixed in on both aeroplanes as all access will be from underneath via the removable wing and access hatches:

topdeckson.jpg

That's it for now, hopefully I will get some more work don on them this afternoon.

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Well another report will be forthcoming soon, just thought I'd relate today's little drama!

For a brief spell it looked like my sloper version would not get off the ground, well it wouldn't, not after I'd joined thr two wing halves together... ...I did not use a big enough piece of plastic under the wing & it ended up epoxied to my work top crookembarrassed.

Two choices then, make the worktop into wing, dont knowsarcastic or since the epoxy was only an hour old lift the wing and smartly whack the edge of a ruler under the wing to break the bond smile o.

It worked smile. Only an insignificant amount of wood stayed with the epoxy on the bench and a scraper soon had the worktop cleared of that and the semi cured epoxy.

Phew, that was a close thing.

Edited By Ian Jones on 17/05/2013 18:25:05

 

Edited By Ian Jones on 17/05/2013 18:27:27

Edited By Ian Jones on 17/05/2013 18:28:17

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We've all done it Ian - or something similar! I had a parallel experience a little while back - I was repairing one model whilst fixing decals on to another (trying to be efficient!). I ending up putting the wing of the brand new model down into a pool of wet expoxy prepared for the other! smile o

A great many words that would get me banned from the Honourable Society of Gentleman Moderators issued forth - fortunately I was just able to save the day with the quick application of a little acetone! As you said - close thing.

Nice progress so far. I too am intending on using snakes in this model - simple, rugged and reliable - a bit like me! smile d

BEB

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Ah well at least I'm not alone in the daft mistakes dept.

Speaking of not being alone, Greenacres fly-in is approaching fast and there's still a fair bit to do. I think I will have to concentrate on finishingthe IC version. The risk is putting the sloper to one side and never finishing - the way the weather has been it might be the better bet!

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Too right.

I'll be doing a full update soon but as things stand it looks very much like the battery will be going in the tail. There may be an additional battery for wheel brakes which I haven't decided whether to pursue or not - some R&D over the next few days will decide.

Ian

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Since we have been talking about wheel brakes I'll pause on the build briefly and show where I'm up to with them.

This isn't what I originally had in mind but time is marching on and so I've considered more conventional ideas and come with this prototype that should work:

wheelbrakeptypesml.jpg

brakeonoffsml.jpg


The protusion sticking out sideways near the servo is just some leftover wire after bending. I also tried using fuel tubing as brake pads and that seemed quite effective.

So that's the concept I will go with, for now though it's back to the sandpaper )

 

Edited By Ian Jones on 27/05/2013 15:52:59

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More work on the wheel brakes and I think I have now done enough development work to take the 2nd prototype to the final version when fitting to the model. The main difference will just be a curve on brake shoe to provide a larger contact area.

So this is how it looks now:

wheelbrake2ndptype.jpg

The U/c leg has a short length of snake outer epoxied to it, the push rod is looped back on itself to form the foot and the silicon tubing shoe slides over it (with some hard pushing). The side bar coming from the outside collet prevents the assemby from moving in any direction other up and down.

Here's a little video:

Ian
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Nice - very simple, and probably quite effective.

Are you planning for a proportional channel so it isn't all or nothing? - could hurt if they wheels just lock! Or you could use a servo slow as used for electric retracts so the braking is gradually applied...

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Posted by Biggles' Elder Brother - Moderator on 30/05/2013 09:58:04:

How about reverse thrust next Ian? wink 2

BEB

Edited By Biggles' Elder Brother - Moderator on 30/05/2013 09:58:21

Hmm, could be done with a variable pitch prop, hmm, dont know no, no, stop it! wink 2

A forward facing umbrella type thing behind the prop perhaps?, no, I said no disgust nerd.

 

.

 

Posted by Olly P on 30/05/2013 09:18:51:

Nice - very simple, and probably quite effective.

Are you planning for a proportional channel so it isn't all or nothing? - could hurt if they wheels just lock! Or you could use a servo slow as used for electric retracts so the braking is gradually applied...

Yep, simplicity is the thing. Apart from the tube epoxied to the leg the whole lot can easily be dismantled and reassembled in next to no time. The original intention was just to stop creep on tickover so an on/off application would have served well for that. I think that it has turned out better than planned though so I will probably use a proportional channel - even application would be critical for rolling application or a sudden change in direction could result smile o

.

 

Posted by Biggles' Elder Brother - Moderator on 29/05/2013 22:32:36:

What stops the bit of fuel tubing from just rotating driven by the wheel Ian? Is it just a tight fit or have you sneaked a bit of CA in there?

BEB

PS Neat idea BTW! Very impressed!

Edited By Biggles' Elder Brother - Moderator on 29/05/2013 22:33:02

 

Yes BEB it's stretched quite tight and I think that as the looped wire does not create a round axle that reduces the tendency to rotate. I had intended to insert some adhesive as you suggest but it doesn't seem to be necessary.

.

Thanks for your comments chaps - now to go and cut the nose off!

Edited By Ian Jones on 30/05/2013 11:57:25

Edited By Ian Jones on 30/05/2013 12:01:18

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Posted by Martyn K on 30/05/2013 12:04:03:

That looks very good Ian.

10/10 for initiative, I like it. It will be interesting to see it working. Taxi to the end of the strip, open the throttle, release the brakes - can't wait.

Martyn

Engine going in tomorrow, (see I hadn't forgotten about it), hopefully undercarraige (and brakes) too. That will mean everything that has fixed position will be in place and I can then work out where the other servos & battery will go to balance the model.

I do have lots more photographs to post but my neck is in bad shape at the moment and time at the computer makes it worse.

 

Posted by Olly P on 30/05/2013 12:36:32:

Hmm...reverse thrust on a 'leccy motor could be done, but would need some clever electronics....

Very nice Ian - I might have to steal this idea!

Erm, never heard of copyright Olly wink 2. Help yerself lad... hope it doesn;t fall too bits during testing now!

Edited By Ian Jones on 31/05/2013 22:39:12

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Some catching up with where I'm up too...

Last time out I had added f4 & F5 to the cockpit floor prior to fitting to the fuselage. I did it this way so that I would have something to put in the rather large canopy to see how it would fit:

canopyfittest.jpg

Hmm, looks like I'll be cutting a lot away then!

Having found out what the situation os with the canopy, the question of pilots has arisen. Once again I bought my supply from Vortex Vacforms and they are fine, by coincidence though look what was in my spares box:

pilotsspotthediff.jpg


I've searched the internet to find out if the Protech pilots are still available but had no joy. My friend Tom Doyle is getting some pilots from HK and has added in a couple for me so one way or another I'll have enough suitable pilots - I should think so too!

Right back to some actual building and I've fixed the cockpit floor together with it's formers in place and moved on to the ailerons. The sloper is a CNC kit build but the IC model is from scratch so I've had to cut the ailerons from the wing - I'd been dreading it but in the event it wasn't a problem with a brand new blade in my modelling knife:

aileronscutfromwing.jpg

For aileron torque rods I've bought the part made jobs which just need the sleeve cutting to length and then bending to fit the aileron. These are 14 SWG and bend fairly easily:

ailtorquerodbending.jpg

ailtorquerodonplan.jpg

Having cut the rod to length the next job was to cut a channel in the wing to take the rod ensuring that it will end up in line with the hinges:

rodcentreline.jpg

I've used a number of methods for cutting the slots for the hinges and not been happy with any of them until now. What is the revolutionary method? A sharp knife, a keen eye and no measurements - it worked a treat. So I was soon able to start to address the matter of the removable wing. Having pondered and procrastinated I decided to simply use four wing bolts and so fitted the wing bearers of good solid hard wood then drilled through the wing and the bearers in one go to ensure the holes lined up ok. Oh and in each hole in the wing I've pushed through a length of snake outer covered in epoxy. When that dries a cut top & bottom produces A nice neat, robust bolt hole strengthener:

snakeouterwingbolthole.jpg

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Now then as the wing bearer is already fitted in the aeroplane it's hardly practical to hammer in the T nuts - there's been problems but not enough to deserve that ! The answer is to use a cap bolt as a puller to tighten up the T nut until it is well seated:

tnutfitting.jpg

That all worked okay, so time to do some more sanding for change! This bring onto the underside access hatch which I screwed in place before sanding - that way it can be profiled along with the rest of the underside and hopefully produce a nice neat job. I'm toying with the idea of sinking the screws then covering the hatch as if it was a permanant part of the fuselage. I don't expect to need access after covering but if I do then I can always cut the covering. Hmm, still pondering on that one, in the mean time:

undersidehatch.jpg

... and I've started shaping the nose too:

startednoseshaping2.jpg

Anybody wondering how I'm going to get the engine in? dont knowsmile

Now to the other end. I've fitted the tailplane (no horizontal stabilizers is this house, thank you). To stand some chance of getting the fin/tailplane fillets about right I've decided to mark them out and shape them now. If they are not quite right I can do some final tweeking when fitting but I think that will be a lot easier than waiting until the fin is fitted:

finfilletsmarking.jpg

So it's on with fin, (no vertical stabilizers is this house, thank you) and the fillets. You might notice that the fin extends forwards onto the fuselage decking by 1/4". Well I've made the fillet 1/4" higher too. Well the engine I'm fitting is a little on the powerful side so a little more fin might help counter the torque at lower speeds, we'll see and I think the stand-off scale can handle it without it looking odd. That engine is also the reason for the wheel brakes mentioned earlier. I've used a length of hardwood to join the elevator halves as I didn't have the right size dowel to hand when I came to do the job:

finelevinplace.jpg

Back to the wing, well the undercarriage actually. I hadn't actually worked out how or where I was going to fit the servo(s) for the brakes and I need to be making some progress - time is marching on. So a quick and easy answer is needed but it must be one that will work too so in the end I decided that a servo for each brake will be the easiest with some modification to the plates for the undercarriage to accommodate the servos:

servoucmount.jpg

I knew that GCE woodwork would come in handy one day! This arrangement means that the extra work on the wing is minimal - just a shallow channel for the servo wire on each side, especially handy as it just so happens the length of the servos wires matches the distance to the wing join; that should work out well. So this layout gives an idea of how it will be done (ignore the plan underneath):

mainucparts.jpg

Right in the previous post I mentioned that it could appear that I have no provision for fitting the engine... well I had a little plan all along:

offwithhisnose.jpg

Off with his nose! That cut is strategically placed to match the rearmost need to accommodate any sticky outy bits, namely the rear main needle. Having cut off the nose the firewall is exposed so the engine mount can be fitted - wow that was a tight fit, but fit it did and the next job is to cut away as little as possible of the nose, now the engine cowl, to make room for the exhaust etc.

 

Edited By Ian Jones on 06/06/2013 02:13:39

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