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Author Topic: Nieuport 11 Bebe - Build  (Read 33285 times)
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Pete Fardell
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« Reply #25 on: May 09, 2015, 05:18:23 AM »

The cowling will look great. What fun to use a hammer on a model- and not even in anger!
 I'm really glad you're going with scale upper wing (non) dihedral too, and wish I had with mine. I thought I'd get away with it due to the sweepback disguising it a bit, but because I made the dihedral breaks each side of the centre section, rather than at the centre itself, it just means the whole wing has a strange looking kink to it from certain angles. Anyway, after your Dr1 it should be a doddle to trim.
(The old Eric Coates maxim is that, from a stability point of view, 3 degrees of sweepback is approx equivalent to 1 degree of dihedral)
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Rich Moore
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« Reply #26 on: May 09, 2015, 06:12:51 AM »

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after your Dr1 it should be a doddle to trim.

The Dr1 was a doddle to trim. I didn't do much to it at all - the only 'trim' required turned out as 1/16" up on starboard aileron. It has no thrust adjustment at all (yet). I made it look hard by being slow to add enough nose-weight (Bill had some influence here) and add a wider bladed propeller (I am going to make a new prop with even more blade area). The whole exercise taught me that dihedral is over-rated, or at least overly worried about, at least at this sort of scale. There was quite a bit of speculation about 'correct' wing and tail incidences, but I built it as the full size prototype and funnily enough it was fine. It also taught me the importance of crash-a-bility to survive my inability to get things right quickly. I am going to take these lessons into this build with me. I will stubbornly stick to full size incidences, sweep back and dihedral, get the cg well forward (ali cowling...and a bloody great engine) and I hope to achieve a similar result of disassemblage (!) on impact with obstructions (the ground) as the tripe.

That's starting to sound like a mission statement...
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billdennis747
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« Reply #27 on: May 09, 2015, 07:00:34 AM »

Rich, you obviously are adept at aluminium-bashing. I never was, despite Terry Manley telling me how easy it was (but then he worked on aircraft). He said the key was to use pure ali sheet and keep annealing. I think when I tried it, my ali was too hard  No chance with litho plate, I think.
How are you going to attach the top wing?
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Pete Fardell
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« Reply #28 on: May 09, 2015, 09:16:57 AM »

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after your Dr1 it should be a doddle to trim.
The whole exercise taught me that dihedral is over-rated, or at least overly worried about
It's taken me years to start to believe this, despite Bill and others saying so so often. Once you stop worrying about it it opens up a whole raft of new subjects.
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packardpursuit
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« Reply #29 on: May 09, 2015, 10:33:26 AM »


Rich said "The whole exercise taught me that dihedral is over-rated, or at least overly worried about"

Pete said "It's taken me years to start to believe this, despite Bill and others saying so so often. Once you stop worrying about it it opens up a whole raft of new subjects."

One of life's "ah ha!" lessons, especially as I get older (I'm 65) has been the discovery that we, as humans growing up, are largely trained to tune into negativity. In modeling it is the "It can't be done attitude" oft exhibited in these very forums.   "We can't use scale tail outlines", "can't use scale dihedral" "scale airfoils" et al, etc. I think we worry so much about thinking "it just isn't done", we miss out on many of the things we actually can do, and forget to even try.

Now if i had just learned that at a much younger modeling age, I wouldn't have wasted so much valuable time and abundant energy developing such a mental block, in the first place!!!
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dorme
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« Reply #30 on: May 09, 2015, 10:53:52 AM »

I fully agree with you, PackardPursuit on those statements of accepting the norm.  It tends to leave many of us to not think about reinventing the wheel. I have found that there are times went one needs tail weight or upthrust. 
As far as dihedral, I have seen Ray Harlan fly scale aircraft w/o any dihedral, and we were amazed!
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Mooney
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« Reply #31 on: May 09, 2015, 12:39:45 PM »

Hi PackardP,  too back up your statement, about 11 or so years ago, there was a nice guy that came into the bulletin board forums and happily posted photos of his many models w/o dihedral and stated that ya don't hafta have it.  The reaction was quite negative.  Shame he was more than happy to discuss his models and techniques, but was roundly dismissed.  I built a Dr1 from Skyraider's Lee kit and I didn't trust myself to be able to trim it w/o dihedral, so I added it.  The Dr1 was stable and I flew it in the wind, but it was proven to me when I saw another flying well w/o dihedral.  FTR, mine was light, but no record setter.  I will do another w/o dihedral.

Awesome stuff so far Rich.  How can I get anything done when you are building stuff like this? (Grin)

Moon
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billdennis747
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« Reply #32 on: May 09, 2015, 02:19:47 PM »

there was a nice guy that came into the bulletin board forums and happily posted photos of his many models w/o dihedral and stated that ya don't hafta have it.  The reaction was quite negative.  Shame he was more than happy to discuss his models and techniques, but was roundly dismissed. 
One thing there is never a shortage of in scale is experts telling you 'it won't fly'. When I began around 1965 I bought a book by Ron Moulton called Flying Scale Models. An excellent book for its time but I took too seriously the statements that models needed a minimum of 3 - 5 degrees dihedral and 25% tail area. Since then I have lost count of the number of 'impossible' models I've seen fly. Off the top of my head, some of these I have flown or witnessed include
Nieuport 11, 17, SPAD, DR1, Fokker DVII, DVIII, DV, EIII, Albatros DV, Spirit of St Louis, Morane  N and Parasol and Lacey!
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daveh
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« Reply #33 on: May 09, 2015, 05:28:18 PM »

All these posts regarding dihedral etc. have got me convinced to the extent that I've just altered the top wing on my little Sopwith Tabloid (build over on micro R/C) and rather than messing about with incidences, decalage etc. I'm redrawing the fuselage plan with scale values. Maybe Tommy Sopwith and Fred Sigrist knew what they were doing?

Back to this topic - looking good Rich, especially the metal bashing. Test flights at OW next week?

Dave
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Rich Moore
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« Reply #34 on: May 09, 2015, 05:35:52 PM »

Cowling practice over! Nearly, but not quite. I'm not happy with this and will make another. Main problem is, at some stage, the aluminium has ridden up the form slightly without me noticing, and I've lost 4mm off the overall depth of the cowling. Really need to tighten that clamp right up! I am happy to have managed to get enough flat on the front of the cowling though. I was worried I wouldn't be able to achieve this. There are two 'beginnings of folds' that tried to spoil it, but these have proved to be easy to tap and polish away. Worth bearing in mind for the next one. Plus quite a few dings where I've got a bit too heavy handed. They would polish out eventually but I need to listen to Eric and get a hide hammer.
Things I must do better - more patience ie. more tapping, less banging. More frequent annealing. Tighten the clamp tightererer.

For reference, this cowling weighs in at 30g.
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Re: Nieuport 11 Bebe - Build
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Rich Moore
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« Reply #35 on: May 09, 2015, 05:41:29 PM »

Hi Dave,

I believe that if you set incidences as full size prototype, the aircraft has much more chance of 'sitting in the air' like the full size one.

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Test flights at OW next week?

I reckon I could chuck the cowling like a frisbee further than some models I have built. Unfortunately I won't be at OW until July  Sad.

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Ployd
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« Reply #36 on: May 09, 2015, 08:19:51 PM »

Hi Rich Moore

As an ex aeronautical "tin basher" I would suggest that for your next cowl you extend the width of the sheet by at least 6 to 8mm below the finished depth line of the cowl to allow for creep. You can tighten the clamp only so far but during the forming process the aluminium will move. When hand fabricating a cowl with such a deep draw I would add extra metal at the top and use a lemon wood mallet with a wedge shape nose and a hard wood backing bar which allows you to drive the metal down to the form (effectively stretching the metal) and shifting the resulting puckers into the centre of the form block where it can be trimmed away. For plenishing, I always used a light weight turned aluminium hammer with a slightly domed highly polished face. A panel beaters hammer would do the same thing.

Ployd in OZ
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packardpursuit
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« Reply #37 on: May 09, 2015, 08:52:25 PM »

Rich
Really enjoying the aluminum forming! Keep it up. Ployed seems to know what's  what. Me personally, I would have tried to spin the cowl full round and then trimmed the non- Nieuport areas.

When we built our full size Nieu[port 82 E, we had cowls spun. Quite an eye opener. Hardest part was making/turning the hardwood form, which due to atmospheric instability, tends to move, even self-destruct very quickly. IIRC, we had four cowls turned. One for us and some to sell. All were gone within a year, two tops.

Regarding scale setups of decalage , incidences, and washout etc, I agree that is GENERALLY the best place to start, even for rubber scale models. If you think about it, using non-scale but "traditional" or "typical" model set ups, renders a flying machine that is not at all a dynamic representative of the prototype.
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Rich Moore
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« Reply #38 on: May 10, 2015, 04:25:04 AM »

Thanks Ployd, I have a new piece all ready to go that'll cover it. I think I needed to get one out of the way to get the learning embedded in my head. I like to call it 'failing to learn', in other words, you learn more from failure than getting it right first time!

If I get this cowling right, I know it will be immensely satisfying.
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billdennis747
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« Reply #39 on: May 10, 2015, 04:40:14 AM »

It's always a good idea to get the hardest bit out of the way first! Also, it lets you build the model to fit the cowling, rather than the other way round.
Since I haven't the skills to bash cowlings, my approach is to wander around hardware shops looking at aluminium pots and pans and kettles. The staff look sceptical when I get the calipers out. I don't care if my model is 1/8.736!
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Rich Moore
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« Reply #40 on: May 10, 2015, 04:54:26 AM »

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it lets you build the model to fit the cowling, rather than the other way round

Yep, this is part of my logic. My Dr.1 cowling came out eeever so slightly too small. Partly because I had originally made the form for .7mm ali but ended up using it with very thin plastic.
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packardpursuit
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« Reply #41 on: May 10, 2015, 11:58:17 AM »

Scale modeler's constant dilemma! I came to feel that "off the self" and "scale" didn't necessarily coincide! Could never understand why William's Bros. chose odd diameter's for their smaller WWI wheels??!! Seemed they never had right size for my 1/12 scale WWI fighter projects. And while their engine cylinders and guns were in rather standard scales(1/12-1/8-1/6 and even 1/4) I could never find a standard scale need for 1-7/8 diameter "clincher". Oh well. Grin
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« Reply #42 on: May 13, 2015, 10:51:22 AM »

I believe that if you set incidences as full size prototype, the aircraft has much more chance of 'sitting in the air' like the full size one.

It all depends. If you fly it in similar parts of its speed range, in relation to the stall, to how you imagine the full size flying, then yes. similar angles will tend to do that.

Take a full size WW2 fighter, its sit in the air at full speed straight and level (maybe 4x the 1G stall speed) will be much more nose down that at a normal cruise (maybe 2.5x 1G stall speed) and very different again form its attitude at the speed for best climb or best loiter time (maybe 1.5x 1G stall speed).

With a well powered RC model you are covering a similar range of speeds to the full size. But often with free-flight, especially rubber free-flight, we are trimming for  a much narrow speed range, generally much closer to the stall, probably around the 1.5x 1G stall speed, to make good use of limited available power. So with scale angles the aeroplane will tend to sit quite nose up just as the full size would the low end of its own speed range. In those cases a bit more positive incidence will make more nose-level, a bit more like the aeroplane we are accustomed to see in the war movies or air shows.
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Rich Moore
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« Reply #43 on: May 13, 2015, 04:58:30 PM »

Had another go at the cowling. Failed - not in the right frame of mind at all - much too angry!

I had another go and got these two pictures along the way. This one might be OK. The dimples aren't too deep and I have had a go on a bit with some fine grade wet/ dry which proved promise. I did end up with a few folds within the finished area, but these were flattened out against a solid steel block and aren't too easy to see now. I don't think I can planish a better finish without a harder form, so a process of wet/dry followed by a jolly good polish with something like Brasso will have to suffice, unless someone can suggest better. I will no doubt vacuum form a few spares.
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« Reply #44 on: May 13, 2015, 05:22:47 PM »

That's looking good now Rich .... I've got to have a go at this sometime so that I can feel your pain!
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Rich Moore
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« Reply #45 on: May 13, 2015, 05:33:17 PM »

You should definitely have a go. I think I need to get my hands on some better tools. Biggest problem is that this particular cowling comes so far round to the front and it is really difficult to get the folds away from the final cowling area.
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« Reply #46 on: May 13, 2015, 05:43:52 PM »

I've been looking at a few things .... one of them was the Sopwith Baby (complimenting the Bebe?).
This has a horseshoe cowl that I guess would be a little easier?
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Rich Moore
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« Reply #47 on: May 14, 2015, 02:29:12 AM »

Cool. Have a go. It is an interesting process. I think it is a rewarding one - will be if I can get the finish...
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billdennis747
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« Reply #48 on: May 14, 2015, 02:43:37 AM »

The nearest I got to doing this was to modify a commercial cowl over a wooden form to alter its profile slightly. This for a Sopwith Triplane. I used pretty coarse wet and dry to remove blemishes and then gave it to my friendly garage to buff up on the polishing wheel. It came out perfect - too shiny possibly for the Bebe but I was then adding the engine turning.
If you end up with a small hole or crease, it might be worth looking into aluminium welding - add a blob and file it down. There's a bloke at the August Nats every year. I'm sure it would be the work of seconds for someone who knows what they're doing.
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Rich Moore
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« Reply #49 on: May 15, 2015, 05:12:05 PM »

I've finished with all the tapping. Now it's all about rubbing. The biggest dings have been independently identified and tapped out from the inside with a hammer over a metal block. If I could produce a steel form, which I can't, I imagine the planishing process would produce a much better finish. Because I have had to use a soft, mdf form, I've ended up with a dimply cowling. However, nothing that can't be smoothed out...

...I've started with a medium file, moved on to 80 grit sandpaper, then 400 grit wet/dry. Picture here is after a good going over with 600 grit wet/dry. There are still a few dings that need a bit of attention, but these will go. I will save any further polishing until I have cut out the final shape.

The next step is to work out the shape of the cut out. The shape of the cowling cut out in the 3-view doesn't match the photos I have studied so far. I need to determine if this is an error or the drawing features a different type of cowling.
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Re: Nieuport 11 Bebe - Build
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