Bistormer 60" (A Barnstormer with more ribs)

[Danny Fenton]

Thanks Colin I think the pack will end up as far back as i can go, ie the first pic.

Glad you found the wing dowel allignment ingenious kc, I was pretty chuffed too and haven't seen another way suggested, other than drill through from the front with the wing clamped (somehow) in place. Always ends in disaster for me as inavriably something slips lol. This way was really simple and very accurate, and best of all required only gentle persuasion with tools, nothing big and aggresive

Hi Barrie, I have a bent Dural undercart that was supplied by DB so that will form the basis, I have some hardened steel 4mm bolts that will act as axles, I hope they withstand my landings, if not then they are easily replaced

Motor is long since discontinued, it is a TowerPro 3520-7T and will draw around 750 watts on 6S A123 spinning an APC thin leccy 11 x 7, if memory serves me right

There are better and much lighter motors around nowadays. The 4260 was a big favorite of mine, and could be pushed to 1kW easily, but again they have become unnavailable. The 4250 should be a pretty good choice, and lighter. I have two 4240 SK3's in the Apache I am currently building. So I guess the clue here is a 42mm diameter can with something around 600kv should be good for 5S LiPo or 6S A123 (volts per cell are lower)

Hope that helps?

Cheers

Danny

[Barrie Dav 2]

Re the axles Danny, I'd be interested as to how you get on with the 4mm (H.T. ?) bolts. You're making a superb job of this model and your build posts are first class. I'm looking forward to your next project .

[Danny Fenton]

Thanks Barrie

still bashing away at the upper cowl....

First of all the top of the fuselage was edged with 1/64 ply

Then the ply and bulkhead was covered with a layer of sellotape

Additional pieces of 1/64 were added and then I started adding block. I hate building with block, seems so wasteful....

More block

I needed to have a reference at the front, so I made two ply disks, one with a central hole, a snug fit on the motor prop shaft. The other disk is just a ring.

Both disks are used to allign the F1 disk

Close enough for now. You must remember that this disk is the same diameter as the spinner, so you mustn't sand the fuselage into this ring. I will show more of this later.

I had intended to fix the nose section to the fus and only remove the middle hatch bit, but because I have used dowels to allign the rear it needs to slide forward to come off, so I had to change my mind. I added more 1/64th and started blocking in the front section.

More blocks are added to infill to this new outline

Then the razor plane was pressed into service, I don't know a modeller that doesn't love to use the razor plane As my chum Mr Hooper would say keep sanding, there IS an aeroplane in there somewhere....

Cheers

Danny

Edited By Danny Fenton on 21/02/2014 23:46:56

[Danny Fenton]

With all the activity on the Barnstormer threads I thought I had better do a bit more on my BiStormer.

So the front end got sort of finished off....

just need to add some magnets to hold it in place and we can move on to building the horizontal and vertical stabilisers

Cheers

Danny

[Ian Petherick]

Danny

Have come into this a bit late as I have only a few minutes ago come across your Build-log.

I have a Bi-Stormer under repair/rebuild. It began with an original kit from DEB about 1980. Several poor arrivals proved some of your comments as to its rugged ability to accept the knocks and bumps. Landing inverted at moderate speed was beyond it and so there is now a completely new wing structure awaiting covering.

Many house moves, changes of weather and fuel/oil residues put paid to the original glued joints and some of the timber required new stringers and lots of regluing about the fuse.

The intention is to change to elec power as there is another Bi-Stormer at my local club and it performs so smoothly using a Turnigy 60 motor. (Don't know the KV)

Cheers, Brisbane, Aust

[Nigel Day]

Very nice Danny.

I'm being dense but I'm missing the purpose of the two ply rings and when F1 makes it's appearance. I see what looks like the two rings you've produce but one of them appears to be glued to the sides of the fuse. Or is one of the rings sitting inside F1 and the other, larger ring, on top?

Is blocking the top much easier than making a sheeted and stringered cover with front and rear former? I thought I'd make the top covers the latter way.

Nigel

[Danny Fenton]

Hi Nigel, no it's me I haven't been very clear, sorry about that.

I needed to know where the spinner backplate would be, so I made a dummy disk from ply. That is the solid ply disk. My version of F1 is the other ply disk with the centre missing, the doughnut or ring The doughnut (my F1) is attached to the fus using the ply spinner backplate disk as the reference. Once the doughnut/ring is attached we discard the solid ply disk.

As for the front cowl section being solid, there is no reason at all for not making it from bulkheads and stringers. However it tends to be a part of the model that gets handled a fair bit and in the case of an ic model where it is often held while starting, so it needs to be fairly rugged. Add to this the fact that full size aircraft are seldom fabric in the cowl area, so using block looks right. Also the curves are often quite bold so is easier from block.

Hope that helps?

Cheers

Danny

[Danny Fenton]

Found four small squares of Kryptonite to hold the cowl top on. Kryptonite is far stronger than Neodymium magnets but is quite difficult to find....

Cheers

Danny

[Colin Leighfield]

That's a very Hawker Hartish front end, right up my street. If the Kryptonite doesn't work, I have got a bit of anti-matter lying around that you can have. It might also project the Bi-Stormer into a parallel universe in the process, but it would certainly be interesting.

[Danny Fenton]

Hi Colin funnily enough a Camm design was my intention, but i think trying to make this scale is not really going to work so we will push on as a Hawker Bistormer The postman guarantees me this Kryptonite will work, well the guy was wearing red, think it was postie, the cape threw me though. I did have a job washing off the green glow, bit of acetone sorted that. Postie (or however he was) seemed anxious to get away from it to be honest

Contain yourself on the Anti-Matter for now

Cheers

Danny

[Colin Leighfield]

I'll hang on to it for now, let me know if you fancy giving it a go. Most people don't know that the C in my name actually stands for Clarke.

Sorry that some of the green glow rubbed off on you, I'll be more careful in future. Sorry to inform you though that it will cause your ears to drop off, although it usually happens about 2,500 years later, so you should be ok.

[Barrie Dav 2]

Never trust a bloke who wears his pants over his trousers Danny. Beware - I'll bet that that Kryptonite will be a cheap Chinese copy.

[Nigel Day]

Thanks Danny, on both counts. Building it from block (despite your bleating ) makes sense.

[Colin Leighfield]

I hope that Barrie isn't questioning my credentials, the external underpants might be a bit tight, but you can blame Jor-el for that. Kids were smaller in his day.

[Danny Fenton]

Mmmm I haven't seen it on the HobbyKing website, but you might be right It does say Kriptonite on it, that might be a clue? The ears are still intact......

No problem Nigel, me bleating? never

Cheers

Danny

Edited By Danny Fenton on 01/04/2014 13:35:07

[Barrie Dav 2]

As if I would Clarke - er.. Colin.

[Danny Fenton]

right then anough of this silliness, no doubt you all know how to do this but for Nigels benefit and anybody else that wants to remain nameless

A typical "Boddo Tailplane"

Start by cutting out the "shapey" bits. I trace the part on greaseproof paper, flip it over and rub it onto the balsa, this leaves a pencil mark on the wood. Cut the first bit out, check it against the plan and then use it to create the second for the other side.

Using some strip wood, we build the outline of the tailplane over tha plan. Note the protective sheet Nigel

Then we add the spars, these run from tip to tip. The plan shows them ending early, ignore that because the plan is indicating the position when everything is sanded. For now run them full length

Now we add the capping ribs, again the plan shows them stopping short of the trailing and leading edges. Run them full length, when they are sanded to an airfoil shape they will obey the plan

You will perhaps have noticed in the previous shot that we have omitted the centre ribs. This is deliberate. Before adding the top spar and upper ribs, remove the stab from the plan and position the stab over the fus and make sure it is straight by measuring from the tips to a reference point at the front of the airframe. When the lengths are even then the tail is square. Draw line on the tailplane underside to indicate where the fuselage sides meet the tailplane.

Then add the spars and ribs, here the two centre ribs are fitted just to the outside of the lines drawn, representing the fus sides.

Now position the tailplane over the fuselage again and transfer the position of the spar to the fuselage sides.

Using a Permagrit slotter cut a notch in the fus sides for the tailplane spar to sit into. If you havent a slotter one can be made fairly easily by gluing a strip of sandpaper 1/4 inch wide to some 1/4 wide balsa stock

The tailplane should now sit flat on the fuselage

the ribs on the upper surface are fitted so that they straddle the fin. So if you know the width of the fin, in this case 1/4 inch, use some temporary blocks to get the spacing spot on. Be careful to tack the ribs at the front and rear, remove the spacers and then glue more permanently. We don't want to glue the spacer blocks to the tailplane!

Using a long sanding block, or better still a long Permagrit block, sand the ribs to a nice airfoil section. Just get them close with the long block, switching to a smaller fine block for the last bit.

Hopefully you will end up with something like this

And just to keep the morale up

Here endeth the lesson for today

Cheers

Danny

Edited By Danny Fenton on 01/04/2014 17:59:55

[Nigel Day]

And all done for my benefit eh?

I'd send you a pack of chocolate biscuits Danny but I don't think they'd make it through the sorting office your end.

Thanks.

[john stones 1 - Moderator]

Nice work as always Danny

I do like those permagrit slotters

[Danny Fenton]

Well if just one biscuit makes it past the management to me it will have been worth it Nigel

Thanks John, if you haven't built a tailplane via this method before the mess of lines around the centre section is a little daunting. You have to work out which is under which.....

The fin is built very simply, don't look too closely at mine as I have spliced some bits together to make enough stripwood, I wasn't going to break into another strip of 1/4 just for a fin leading and trailing edge!!

Please ignore the dumping ground in the background, two models on the go at once is too much for me, will have to have a tidy up soon....

Cheers

Danny

[Danny Fenton]

Looking at those pics has got me thinking about something I do which you really mustn't copy. I use a felt tip pen to mark up. The pen could show through covering materials, tissue and dope especially. So please don't copy me. I am probably going to use Solartex and paint on this one so its not an issue, other models like the Apache you have no doubt caught me using my pen again, that one is being glassed so again no issue. But its probably a bad habit to get into

Cheers

Danny

[Nigel Day]

If you think that those lines around the fin are a mess on your plan Danny, you should try the single wing version!

The tailplane plan is printed over the wing plan and it's hell's own job differentiating between the two. I'm still considering editing my scanned version of the plan to make 2 versions, one with the tailplane edited out and another with just the tailplane. After my 'fun' with the fuselage side and other's warnings of distortion in photocopies, I'm not so sure.

You've shortened your nose (!) on this one Danny. What are your thoughts on me moving F2 forward 2-3 cms and reducing it in size slightly?

[Danny Fenton]

Hi Nigel, if you can see what's going on with the tail plane then don't worry too much about it, figuring it out is the hard bit! I used a high lighter earlier in the blog to pick out parts of the fuselage, you could try highlighting the tail plane parts from the wing that way?

I know it is probably sacrileges to say this but i don't think that Dave's plans are that well drawn, they are not that clear, perhaps I am spoilt with the Taylor plans.....

I have shortened the nose Nigel because in my opinion the electric powered versions of an IC design end up with the battery pack just ahead of the c of g which is not always easy to accommodate. I built a Flair Triplane and kept the nose the designed length for an IC, I had a lovely battery box behind the fire wall, the model ended up with the batts inaccessible above the lower wing! So to avoid the batts being so far back I now shorten the nose to bring the motor back. Why do you want to move F2 forward? is this to mount your motor further forward?

Cheers

Danny

Edited By Danny Fenton on 02/04/2014 08:56:28

[Nigel Day]

Thanks Danny.

Yes, the motor's about the same size as your's I expect so I'll need to either 'pad it out' as Phil W has done or shorten the nose as you have. I thought an alternative would be to move F2 forward. It looks as though I don't need the increased space behind the engine for the battery (with the ability to move it forward through F3) any more though.

Nigel

[Danny Fenton]

Okay that makes sense, if you have enough room to move cells back should it end up nose heavy then I should just mount the motor on some alloy tubes. I did this on the Apache, not sure if you saw? The only thing you have to watch is make sure you spread the load with washers, and obviously the tubes must be exactly the same length. A metre of alloy tube was about £1 from B and Q

The tail end bits are more or less done now.

I ordered some Solarspan from Leeds Model Shop this morning, I am curious to know what the stuff is like, I appreciate it is a bit heavier than Solarfilm but still lighter than painted Solartex. I wanted to use tissue and dope but I really haven't got time I am supposed to be building a Tinker yet for Greenacres!

Cheers

Danny