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Bistormer 60" (A Barnstormer with more ribs)

Barnstormer with more ribs

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Nigel Day17/02/2014 19:41:13
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1158 forum posts
213 photos

Down in par Danny, nice work.

If mine looks that good, with or without the 'trapdoor', I'll be very pleased!

Danny Fenton17/02/2014 20:43:57
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9318 forum posts
4125 photos
Posted by john stones 1 on 17/02/2014 18:03:50:

I can see it Danny surprise

its just a pimple, not big enough to be a wart wink

Don't you mean I can see them John, there are two hole repairs, do you only see one? smile d

Cheers

Danny

Danny Fenton19/02/2014 15:22:54
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9318 forum posts
4125 photos

The cabanes have been attached after having checked that the wing holes now lie on the flats. I will drill them next.

What have peeps done with the cabanes? I am tempted to round them off a bit...

I am not joking the fuselage has doubled in weight with the addition of these chunks of metal crying 2

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Cheers

Danny

Danny Fenton19/02/2014 18:31:21
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9318 forum posts
4125 photos

Once the cabanes are fixed to the fuselage then we can set the top wing upside down on a foam pad and then allign the fuselage and wing.

I use some kevlar chord from the tail post to the wing tips to make sure the wings are true.

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I use a piece of tape wrapped over the chord, this can be slid along the chord to make the measurement.

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Here you can see strips of A4 attached to the wing with masking tape. A BBQ skewer is pushed through the A4 into the wing bolt holes in the wing. This is a very similar idea that is often used to allign fibreglass cowls.

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The fus is once again placed over the wing and checked for true again with the chord. The paper slips are positioned over the cabanes and the holes position transferred to the alloy cabanes.

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These are then drilled.

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The allen headed bolts are fitted through the holes and bolt the wing to the cabanes and fus.

Cheers

Danny

kc19/02/2014 18:44:53
6300 forum posts
170 photos
A very neat way to mark the position.
But what stops the bolts crushing the balsa when tightened and changing the incidence? Or is that ply instead of balsa or is there possibly some tube as a stand off?
Danny Fenton19/02/2014 19:05:52
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9318 forum posts
4125 photos

Hi KC, you are quite right there is only balsa above the ply plates. The plans show that the cabanes are recessed into the balsa skins so that they are flat aginst the ply plates inside. The cabanes is much thicker than the wood so they won't be fully recessed, only partially. I will draw around the cabane "feet" and remove the balsa to make this happen wink 2

Cheers

Danny

john stones 119/02/2014 20:10:24
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11193 forum posts
1507 photos

its looking good Danny

very tidy work, I like outer stringerlongerons they add character to the fuzz

love tips you add in, its good stuff

had seen both holes, was trying not to be too critical cheeky

Danny Fenton19/02/2014 23:22:58
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9318 forum posts
4125 photos

Thanks John wink 2

Bit more done this evening, but first a morale boosting pic from earlier....

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The wing sheeting was routed out KC so that the cabane sits on the underlying ply wink 2

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This little slither of 1/8 sq all around the cockpit/cabane area is F26, it took some figuring out but I got there in the end. I also sheeted in the area where the pilot will be sat.

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The sheeting that covers the cockpit area is 3 1/2 wide so had to add a bit to some 3" wide 1/16

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A bit fiddly and there are one or teo gaps down the side, but it is attached securely to that 1/8 F26 so the gaps are aesthetic rather than structural.

Will take a look at the nose section tomorrow, need to create a battery tray of sorts and a hatch type afair smile

Cheers

Danny

kc20/02/2014 11:45:15
6300 forum posts
170 photos
.
Are the mounting bolts steel or are nylon to be used? And would you advise everyone to use steel or would nylon be better for the newer pilots?
Danny Fenton20/02/2014 12:22:45
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9318 forum posts
4125 photos

Hi KC the bolts are steel. The plan also indicates steel bolts, I hadn't even considered nylon to be honest. I usually find that if a model crashes badly enough for the nylon bolts to shear the rest of the model is pretty badly damaged. I nearly always use steel.

Good point though wink 2

Cheers

Danny

kc20/02/2014 14:02:52
6300 forum posts
170 photos
On other models the usual way is a dowel at front ( or two dowels) and 2 nylon bolts ( maybe only 1 ) In a typical wing catching ground incident I have noticed the dowel pulls out and the nylon bolts shear ( observing other peoples accidents of course! ) So I think 'nylon' bolts do work but it depends on circumstances.

Wing bolts come in two types -SLEC do two types, polyprop which breaks more easily than nylon which they say is tougher and virtually unbreakable..
Whether the Bistormer and Barnstormer would benefit as they dont have a dowel to slide out is debatable. They would need all 4 bolts to break to have any benefit.
I just wonder if the strut to fuselage bolts would be better in polyprop type. It might break the top fuselage sheeting away too but this might be easier to repair than a wing. It depends a bit on whether you prefer to repair fuselage or wing but newer pilots or those with rough flying sites might consider this idea.
Nylon or polyprop bolts are a bit of a pain to insert to the underside of a wing and anyway they tend to crossthread easily because they are a tight fit even when correctly inserted so you often dont know until the thread has chewed itself a bit. But nylon never vibrate loose during flight. So steel bolts in a Bistormer or Barnstormer wing seem easiest to assemble the model.
And I think I will build a Barnstormer with steel bolts into the wing but polyprop bolts in the fuselage. As it will be electric the vibration problem should not occur - I hope.

Edited By kc on 20/02/2014 14:06:42

Colin Leighfield20/02/2014 14:10:07
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5982 forum posts
2501 photos

It's a fairly big build Danny, but you can see the satisfaction you get from it as it really takes shape. Definitely a keeper.

Danny Fenton20/02/2014 16:14:07
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9318 forum posts
4125 photos

Thanks for the information KC, I wasn't aware of the two types of bolt. As I am usually building a scale model, I push to hide everything, and it is easier to hide a steel fixing than plastic. Its shocking to say but I rarely repair a model, unless the damage is very slight. embarrassed

Hi Colin, I like shaping balsa, the bits I don't enjoy are making metal work fit, and installing radio gear. But unfortunately these things have to happen.

This model is designed to have a couple of dowels pass through the fuselage, just ahead of the leading edge and behind the trailing edge. Rubber bands are then used to fix the wings. This is a fine way to attache the wings and is also the way that the undercarriage is attached, this entailing an additional dowel ahead of the leading edge one, and the two used to hold it in place. I am not going to use rubber bands in this instance as they can cause trimming issues if you don't allign the wing exactly the same each time you fit it. I prefer a couple of dowels in the wing leading edge and one or two bolts in the trailing edge. This is a slow flyer and therefore I will probably two dowels and a single bolt.

One of the jobs I hate is trying to fit dowels to wing leading edges accurately and then making corresponding holes in the fuselage. I stared at the problem for a few moments and have come up with this method, it is an extension of the paper allignment used on the cabanes, that I showed earlier.

First of all we tape a piece of paper to the wing leading edge, and make holes where we want the dowels

00141.jpg

We then continue the paper around the leading edge and tape it down on the other side of the wing.

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Position the wing aacurately back on the fuselage

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Peel the tape up to release the paper from the wing underside.

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Bend the paper forward keeping it taught, and affix it to the fus with fresh tape

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Now carefully lift the wing from the seat, and unpeel the tape from the wing upper surface.

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And stick the paper down inside the wing seat opening. Put the wing aside for now

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Keeping the paper flat against the wing seat bulkhead, transfer the position of the holes.

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Ditto

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drill the holes for the dowels, the holes need to be a nice fit, not to snug and definitely not too lose!

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Two wing dowels were made up about an inch long. Each had one end radiused slightly by putting the dowel in a drill and sanding it while spinning

00151.jpg

The holes in the wing leading edge are deliberately slightly loose, the area where I don't want epoxy to get is covered in a layer of my plan protector, and the dowels snugly fitted so that they just go through the bulkhead and past the radiussed section.

00152.jpg

Epoxy is spread over the dowels and inside the holes in the wing.

00153.jpg

The whole lot is then assembled, some weights are used to keep things still while the epoxy sets.

Never seen it done that way, quite pleased that this old brain figured that out teeth 2

Cheers

Danny

Danny Fenton20/02/2014 23:05:53
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9318 forum posts
4125 photos

Struggled all evening trying to position all the mechanical bits, the battery pack fits where I hoped, but is just a bit taller than I wanted.

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I had two ideas for the front end one was simple the other was difficult and involved making a dummy engine, or at least a cylinder or two. Of course the pack being slightly taller may mean I have to adopt the latter crook

Cheers

Danny

Dave Miller21/02/2014 08:12:21
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341 forum posts
27 photos

I see that you intend using a very small propeller. surprise

Danny Fenton21/02/2014 12:41:35
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9318 forum posts
4125 photos

just goes to show how plans can change. I felt I was backing myself into a corner so ripped all that apart. I know this motor and 6S A123 will go vertical on an 11 x 7.... not that I want that, but it is a known baseline. So I have torn the pack apart, added another cell and made it into a more useful shape. This is the conventional shape I use in many models.

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You can see that even though it is one more cell, it gives us more options when positioning. It also means I can slide it back, as I am am already worried about the c of g even with a 1" shorter nose.

Cheers

Danny

Colin Leighfield21/02/2014 12:45:29
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5982 forum posts
2501 photos

Lots of food for thought here.

kc21/02/2014 12:57:18
6300 forum posts
170 photos
That's an ingenious and clever idea for wing dowels and just at the right time for me...I have a (different) model needing dowels next week. Seems to beat the idea of drilling the hole too low (or high) and filing until it's a good fit.

Could you state the motor and battery details please. There seems such a variety of motors & constant change of availabilty that it's hard to choose what to use.
kc21/02/2014 13:04:12
6300 forum posts
170 photos
Dave, I think it may be rather like a ducted fan!


Barrie Dav 221/02/2014 13:09:24
1012 forum posts
14 photos

What are you going to use for wheel axles Danny? I had one of these in the 1970's (Merco 49 powered) and although I used stainless steel stubs they did not take kindly to the rough landing strip and bent.

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