Jump to content

Bistormer 60" (A Barnstormer with more ribs)


Danny Fenton
 Share

Recommended Posts

It would take me ages, sadly. I am still way behind with the (probably too many) things that I try and fit into the day. Not having fully retired when I should didn't help (this is me pinching minutes in the office right now)!

I want to do another of the mass build models, but there are three things I must finish first and another one is forming in my head now. The most enjoyable conversation I had with you and Chris B. touched on the issue of sharply tapered wings and wash-out, thoughts on that subject will reflect in this one if it comes to fruition.

Last night and early this morning were devoted to getting the long and highly tapered (beautiful in my eyes)! spinner on the Seafang to run true, it's still not quite right. Things aren't helped either because from next Tuesday I will be abroad for three weeks, for the right reasons, (holiday) but it does mess up the building programme and riding my motorbike.

However, the Bi-Stormer is a possibility.

Link to comment
Share on other sites

No doubt you are looking forward to getting away from this bizarre weather though Colin?

A little more progress...

bs 107.jpg

The front side cheeks have been added

bs 108.jpg

The front bulkhead was epoxied in and the sides pulled together

bs 109.jpg

I finished edging the undercarriage box and added re-inforcing blocks to the inside of the undercarriage plate, these are to take the undercarriage screws.

bs 110.jpg

here tis in position. If you were banding the undercarriage on it wouldn't need so much work

bs 111.jpg

The fuselage rear was drawn together and the strip sections added.

I mark the centre of each section and build over a straight line using engineers squares to keep everything alligned.

I added some v soft 1/8 sheet infill at the rear underside of the fus, under the tailplane. Nothing is shown on the plan

bs 112.jpg

Cheers

Danny

Link to comment
Share on other sites

I can't deny it, Miami, 12 days in the Caribbean on the coral Princess, Fort Lauderdale to collect a car and the last week down the Florida Keys. The last rime I drove down there I went past Homestead USAF base and the gate guardian was a Bomarc Intermediate Range (air breathing) cruise missile. I'll see if it's still there!

By the time I get back you'll have this one finished, I reckon..

Link to comment
Share on other sites

Added the top doubler, this the notes says ends at F8 but there is nothing on the plan to say how it ends.

bs 113.jpg

bs 114.jpg

I will build around this bit and see if Davids intentions become clear. I can blend it in but it would be nice to know what the great Boddo had in mind here...

While we are diiscussing the plan, I have found what appears to be a really bad weak spot in the design, and I will have to do something about it I am afraid.

The lower wing seat and its doubler extend back behind the bulkhead F5 by about an inch, this means that at the top of the fus you are bending a 3/16 x 3/16 longeron at the bottom it is nearly half inch thick balsa sheet, the bend is not going to happen equally, in fact it puts a real strain on the longeron where it attaches to the double 3/16 laminate thumbs down

bs 116.jpg

Cheers

Danny

Link to comment
Share on other sites

It says so on the website the instructions are from the kit days so the kit may have had shaped (chamfered) or kerfed parts provided. Just a guess.

When you have sorted out the ideal constrution perhaps you could put it all in print here.
Although this is the most exemplary & informative build blog I have to say I cannot quite follow what you have done on this section, so i reckon there are others in the dark too. Doublers are often very confusing and I usually interpret them by looking at the notches in formers. My view is that perhaps the inner layer stops short of the bulkhead while just the outer layer rests in the notch in the former. Thereby easing the bend or transition. A sketch of each layer might enlighten more.

Edited By kc on 15/02/2014 16:41:27

Edited By kc on 15/02/2014 16:49:05

Link to comment
Share on other sites

Hi KC, on the plan you get one sectional drawing at F3 and that's it! So it is difficult to interpret what's supposed to happen in a completely different section of the drawing eg F8 sad

bs 117.jpg

I will give my interpretation rather than go off and do my own thing, I think that would be more helpful in this instance, don't worry I will try and show what's going on. If it looks like I have interpreted something wrong then please let me know?

I have added the upped formers, I have had to add the top to F3 as I left it off so that I could assemble the fus upside down on the board.

I have added another former, F3a this will give me a bit more structure to curve the sheet on to.

I have interpreted that the area around and in front of the cockpits do not have stringers, but the area back from F8 does......

bs 118.jpg

Cheers

Danny

Link to comment
Share on other sites

Hi Chris that is a great shot and the fus construction is very similar to that, what ever it is? On the one in the pic the upper external longeron goes all the way to the tail where as on my plan it says it ends at F8 which is the pilots head rest bulkhead.....

I may be confusing people by referring to the outer packing pieces as doublers. They are on the outside of the fus sides and build up the shape whilst also adding strength. To me they are still doublers.

Here is the plan, I hope Eddie doesn't mind me showing this, it does show how the fus is built up, provided somebody colors it in for you as I have wink 2

bs 119.jpg

The orange is the main 3/16 side, and attached to this are the 3/16 x 3/8 longerons that go all the way from the nose to the tail, yellow upper outline.

On top of the basic side sections are the red cheek sections and the yellow wing, lets call it doubler, but its on the outside.

I think the underlying orange section should end flush with F5 as it does in the picture Chris has shown. The triangular bit that overhangs is the section that is causing all the stress in the lower longeron.

Cheers

Danny

Link to comment
Share on other sites

Danny, I wonder if the " underlying orange section" is slightly bent in and its the outer "yellow" doubler which fits into the notch in F5? Otherwise perhaps the lower edge of the yellow doubler is sanded away to meet the stringer and is so thin it bends easily? Maybe its deliberately cracked?

Nowadays its so expensive to buy thin birch ply for doublers but it might be worth it for simple strong construction! So many Boddington designs didn't use a ply doubler but the thick balsa doublers makes it difficult to bend the rear fuselage in. My experience is that a ply doubler model is rebuildable after a crash but a balsa box type has nothing left straight enough and not oil soaked to rebuild ( dont ask me how I know this!)

I see that Phil Winks made his Barnstormer forward section as a complete 'box' and then built the rear built up part separately and attached it.
Link to comment
Share on other sites

Hi KC you have to remember I have the instructions and templates so the parts I have identified are correct, and I am pretty sure the placement is too. There is no mention in the instructions about cracking or bending a section

Phil did indeed make his forward section seperate, I think that is Phils interpretation of the drawings, again I defer to the instructions given my DB S&S they suggest the build is traditional full length sides as I have shown.

Anyway thanks for all your suggestions I have added everything I can and this is the result, it all fits the drawings and seems to work. I ended up feathering the end of the triangular upper longeron into the underlying longeron at F8.

bs 120.jpg

bs 121.jpg

bs 122.jpg

There is a lot of planing and sanding to do yet, but I will wait until the upper sheeting and nose blocks are in place.

Cheers and thanks again for all your suggestions thumbs up

Danny

Link to comment
Share on other sites

It's interesting to see the way that people have interpreted the (less than perfect ) drawings, I think every one that is being built is a unique version !

I am just wondering if you might have some issues pulling in the sides to fit F1 it's not clear from the pics if it's already tapered in ??

Link to comment
Share on other sites

Managed to get the other side to the same point. Added a longeron under the centre rear as it would add a nice detail and stop the covering sticking to the box section. I know it's not on the plan but it just had to be done wink 2

bs 123.jpg

Actually is it a longeron or a stringer?

Cheers

Danny

Edited By Danny Fenton on 17/02/2014 00:01:32

Link to comment
Share on other sites

Ah - one man's longeron is another man's stringer!

The fascinating thing about this is that here you are - an experienced builder - with several others also experienced looking on - and we still don't have a definitive reading of this drawing. We have interpretations that obviously work - but whether they are what the designer intended is another matter! As I say, really interesting reading - if like me your a spectator! One advantage of the Dawn Flyer is that Lyndsay's still very much with us to ask!

But I think the lesson here is the way you've approached this Danny. Carefully thinking it out and implementing a sensible solution. There is a good lesson there for all plan builders - because we all face these sort of problems from time to time "what the hell does he mean me to do here?"! I suppose the important thing is not to let it flummox you too much and simply work out a viable solution.

Nice work Danny and beautifully explained.

BEB

Link to comment
Share on other sites

Ah well as long as we all know what we mean I guess it doesn't matter smile

Thx BEB this is possibly not a plan to build from, was okay when you were given lots of numbered bits and a set of instructions. I think I have it as DB intended, but there are a couple of areas that are not clear and you have to assume that they should just be "faired" into the surrounding structure. It seems to be working anyway.

The structure is both stiff and very light, but that is probably because I am controlling the wood selection wink 2 I know it has put a bigger dent in my wood pile than I expected, and will have to spend time in the SLEC tent soon.

Might give their mail order system a go and see how good they are at choosing wood grades.....

Cheers

Danny

Link to comment
Share on other sites

Lots of Boddington designs are very similar in construction and many are clearly enlarged plans. There are so many that I reckon that Boddo may just have handed the plans to one of his DB assistants to build. Therefore as experienced builders they just did the obvious thing to make it work. The actual prototype builders are still around to ask......could it be Dave Toyer who built these first? He is pictured in many Boddo books & articles with these models so I guess he may have built them.

Although there seem to be a few parts that are unclear at least these DB hand drawn plans are accurate unlike many modern plans which seem to have large inaccuracies when they go from designer to publishers. So nobody should be deterred from buying DB plans -they are at least as good as most others.
Link to comment
Share on other sites

Hi KC yes I agree, if you ignore the templates, the plans seem accurate. I think my concern is that a rectangle on this plan is referred to as Fx no reference to material type or size, so you have to work it out. This is more akin to an assembly diagram. I have seen the 52" plan and it contains dimensions for the materials so is easier to build from. Not a problem for me, but we are supposed to be setting an example for those not familar with building from a plan.

Cheers

Danny

Link to comment
Share on other sites

Well the Richtofen plan pack (which I acquired years before Eddie took over) came with instructions which mention part numbers with material sizes. I would have expected current plans to have the same as they come with 'previous kit instructions'

I suppose we are lucky to have these classic plans available still - the RCM (USA ) plans seem unobtainable now and nobody seems to know why!
Link to comment
Share on other sites

Absolutely! Long may they contunue to be available thumbs up

Well I think it was Nigel that termed the phrase shanking a shot in golf, not a golfer myself but I know enough about it to know that when I did the top wing I must have had my eyes shut! In golfing terms I guess I buried the ball in the wall of a bunker crying 2

Not sure I should show you but I guess this should be a warts n' all build, only that way will you know how to wriggle out of the jaws of defeat. I seem to do that a lot these days crook

Anyway, the fus is at a stage where I need to fit the cabanes, now these are unforgiving chunks of alloy and weigh nearly as much as the model! when I positioned them under the top wing things were clearly not right. The holes in one wing were 15mm in from the the rib and 30mm in from the rib on the other wing panel. so the cabanes were no where near the wing holes. I had a pretty good idea of what I had done but there was nothing for it, the sheeting had to be hacked off sad

bs 124.jpg

When I peered inside, the error that I had made was obvious, I had fitted the blind nut plates 180 degrees out on one panel. Stupid mistake, I really should know better embarrassed The blue dot indicates where the hole should be.

Anyway tears aside, what to do. I gave the plates and the anchor nuts a really good shove and they are not going anywhere, good on the one hand, but not helping me get out of the bunker...

bs 125.jpg

It looked like there was just enough room to squeese another plate and anchor nut alongside the errant ones. This is exactly what I did.

Now I just have to repair the holes......

Cheers

Danny

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...