Noris - Bachem Ba349 Natter - Build Thread/Review

Leo said:

yet. Be patient That should change soon.

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Is Robert getting them approved by UK HSE? I hope so - I really want to try those motors! (If "soon" means less than 4 weeks, we get to use them at IRW. )

adrian said:

I tend to use CA to tack down the fins, then epoxy to fillet them. That ought to stick pretty well anything to anything else. Scuff the plastic cone with sandpaper to roughen the surface, which will give the glue a better chance to grab than if the plastic is smooth.

Good work so far! I'm looking forward to the next report...

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well said here. prepping the plastic surface is key!

Ok, the first ones are popping up:

Klima motors in the UK

Leo said:

Ok, the first ones are popping up:

Klima motors in the UK

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From that web page:

Class 1.4S UN0454 just like Estes motors

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That's nonsense for a start. UN0454 is for igniters. Estes motors are UN0432. Klima motors are, I believe, AP rather than BP, which means they'll undoubtedly have a different UN number. And that would mean that anyone in the UK wanting to buy them would need a document called a RCA. To apply for that we'll need the real UN number, and that's assuming that the motors really have been approved by HSE - I wouldn't take that shop's word for it!

adrian said:

From that web page:That's nonsense for a start. UN0454 is for igniters. Estes motors are UN0432. Klima motors are, I believe, AP rather than BP, which means they'll undoubtedly have a different UN number. And that would mean that anyone in the UK wanting to buy them would need a document called a RCA. To apply for that we'll need the real UN number, and that's assuming that the motors really have been approved by HSE - I wouldn't take that shop's word for it!

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Maybe it's a typo?

What is the shop owner saying?

That settles it then the elevators can go on horizontal with respect to the body tube. Just hope they aren't too draggy and pull the Natter over onto its back a'la the first flight with a man in the real thing.

An update on the gluing - I am almost certain I have a duff batch of Araldite Epoxy - I did a test run on it and after over 8 hours its still not form. Its set off but it behaves more like rubber than a hard epoxy 9 quite unlike any epoxy I have every seen so I can only conclude its duff for unknown reasons. Back to the shop I guess to get something different. In the meantime I am giving Bostik Serious Glue a go as it usually sticks almost anything to anything and from past experience you would need a thermal lance to remove it

Meanwhile the boosters are coming along - I had hoped to do a bigger update on Wednesday but family commitments have meant progress has been quite slow.

Time for this weeks update, progress has been a bit slower as I have had some family/social stuff to sort out plus the Natter has moved to a phase where things have to wait while glue/filler etc dries out before the next step can be moved onto.

Since the last update I have been busying myself with the boosters. What Noris supply are some cardboard tube of reasonable quality albeit with fairly deep spirals plus some thick card end caps and some weird things that look like mothballs made out of papier mache.

First job was to glue the papier mache balls in place with some aliphatic glue. These didn't fit at all well being a tiny bit undersized and somewhat misshapen. DONT EVEN THINK ABOUT SANDING THESE BEFORE GIVING THEM SOME HARDENING as they will shred like wet tissue paper.
I glued these in using a digital caliper as a guide to make sure all of the balls were set to the same depth which was very roughly about the halfway mark (hemisphere) on each ball. These were then left to dry. Wisely I never fitted the end caps until the balls were secure as you may need to poke one back out again. You don't need digital caliper accuracy but as I have one laying around it was the easiet way to do it - you could just make a card jig to set the depth the same for each one or just do it by eye.

Once dry each one was given a fillet of aliphatic glue from behind using a taper with a cotton bud taped on to apply the glue, and a good thing too as there was more light looking down the tube than bonded surfaces around each of these.

Once dry you have something that looks like the pic below.

The super observant will notice the back end of the tubes is glued in in the pic above - that's because in all the excitement of building the Natter I forgot to take a picture

Anyway once the balls are nice and secure (fnarr fnarr) the end caps can be fitted. These don't go flush with the tubes but each end cap has a chamfer on it which mates with the tube. Care needed here to make sure they are square on and not off to one side and then steady with the aliphatic glue - blob - on it goes and the tube left to dry.

Here you go with a pic - you can see the outer edge of the end cap is visible rather then being pressed into the tube.

Because the papier mache mothballs were so misshapen there was nothing to do but fill these. Its a real job and a half to build them into shape with filler, then sand all that hard work away in a moment of forgetfulness and have to start all over again :shock:

These were rough filled, sanded then fine filled and fine sanded. Still not happy and a lot of sanding left to do hence only one is anywhere near finished. You need to keep checking them against each other to make sure they are quite similar (if your really hot at sanding stuff you can try for identical )

The spirals in the tubes were filled at the same time plus any flaws in the end caps.

Heres the process so far.....

As the sanding is going to take some time I am deviating from doing one job at a time in the thread and moving on to fitting some of the body together with its wings and fins.

Now Bachem probably had some great jigs when they built the real thing even though it was made of spit and kleenex (Just like the model ) But I bet you couldn't eat the jigs at the Bachem factory

Heres the first jig I used to get the rear stabiliser on - this actually failed and meant the fin had to be cut away again and redone but the first pic does show the advantage of having stuff marked up from the off with the Natter - all those alignment marks make for an easier time getting fins on because the Natter is not round like a rocket and in fact its not even that regular. If you looked at my build in your hands you would see one side is a bit flatter than the other due to the deficiencies in the former/centreing rings. With the great benefit of hindsight, which is one of the finest ever invented diagnostic tools, I would have cut the rings myself and maybe gotten a better accuracy.

The second jig is the most edible of the two being comprised of tins of fish, curry paste and rice pudding - it also worked better at getting that rear fin well aligned. YOu really do need to be able to get a good view front and rear to make sure the alignment is good all round.

I went with the vertical stabiliser first because it was easier to get alignment on a vertical with the kit than to get a good horizontal alignment for the wings due to the shape of the body. The first go was with an Epoxy which just never really set properly for some reason. The second go was with Bostik Serious Glue which needed two hours but its well stuck down now. I may add a fillet of epoxy later to this fin.

Heres the great food stuff based setting jig The body is strapped to a tube marking guide and orientated to be vertical with respect to the alignment marks on the tube and the marks on the centreing ring, a strip of card holds the fin upright, this has been cut to be a good right angle with the glass table surface and have a cut out to allow the body to go under it and a steel ruler taped to a tin of rice pudding holds the fin against the setting guide.

The plastic tri squares are to use as sight guides down the tube to keep an eye on things.

Hard work has its reward - heres the vertical fin on the body, now set near on perfect (thats as good as it gets on this kit).

Also a pic of the current status with the nose on which was for me for use later on in a video. I'd love to do a time lapse but I just don't have the space to leave a kit on a table for very long.

And heres the final bit for tonite. The Natter set up on its jig again - checked to make sure all is vertical (the fin guides on the rear stabilizer are just to make sure it stays upright while one wing is glued on using a stack of CDs to get to the right place (28mm vertically up the body by the instructions) and glued on with aliphatic after the shine has been rubbed off the tube with some sandpaper.

This kit has been a real challenge so far - as Daddyisabar pointed out the instructions show you where bits go but its up to you the builder to work out how to do a lot of it.

Filler is your friend. It covers up all the sin on your Noris kit.

Theres nothing that would cover up that much sin - except perhaps a large brandy - which is where I am off too next

Looking nice and straight. Alignment good, weight still good for a D12 3. The best you can expect from this kit.

she is looking great so far Astro...I have heard of "builder's kits"...but this seems to take that to another extreme!!

Double Plus Builders Kit.

NJRick - its not that bad really, not as hard as I had feared. It would be super frustrating for some I guess but with a bit of thought and patience it can come together quite well. Mine has and I dont rate my skill sets that highly. This is only about the 9th or 10th rocket I have built and the first few were all pretty much shake and bake Estes kits. I'd put this about level with the TLP Perseus II although the TLP components were far more exact. One of the big upsides of this kit, which speeds construction by a fair measure, is you dont have to cut up any balsa. The wings and fins are all precut card which means less sanding and filling and no aerofoiling the shape onto the fins. This is the area I have always had most trouble with along with getting a really sharp highly polished finish.

On the downside with the Natter you need to think everything through and always assume that the instructions and measurements are wrong and not work to a pre-set plan or process so you need a bit more thinking it out - you also need a profusion of glues and fillers because of the plastic/wood/metal parts - so far I have used;

• Poly Cement (Revel)
• Aliphatic (Yellow Wood Glue)
• Epoxy (Araldite)
• Serious Glue (its like UHU gone mad on steroids)
• Plastic Putty (Squadron Green Putty)
• Wood Filler
• Sanding Sealer (I may not need that yet)

and before its done its going to need CA possibly.

So its a bit of an expensive bird to make in materials potentially. Mine more so as I really want to improve my finishing skills so went a bit mad on materials and tools

Perhaps my Rheintochter project made me hard and no kit will ever seem hard again Certainly Schmetterling (the next project) will be a bit of a test of will as well

I agree Astro....sometimes the kits that make you think through steps and come up with processes to complete are far more enjoyable. Just makes watching that first flight so much more enjoyable (and nerve wracking!) this is going to look sweet when she is done!

Normally I don't bother with kits, preferring to scratch-build. The amount of work and modification you have had to do to the Natter means it practically is a scratch-build! I'm almost convinced to get one myself, now. I don't have as much patience as you so if I do get one, it probably won't turn out as well as yours, but hopefully it will at least look reasonable and be able to fly...

Klima D9-3 are now avaliable.

Adrian...its not that bad really. Anyone who can scratch build like your stuff shouldnt have too much trouble. Iw as going to scratch build a Natter eventually but after I saw Daddisabars one i couldnt resist. Your stuff looks a lot more complex like your RheinBote and Thunderbird scratches.

Its not very scale by the way, body is too long and the wings are too stubby and the canopy seems to have the wrong profile so its definitiely sport scale. I would love to have a go later on at one that would glide back after ejecting the motor.

Mine is far from perfect. Its nigh on impossible to get a really great fin alignment, an acceptable one seems the best I can do despite exrecising great patience and care.

Leo...thats noted but I have a pile of D12s to use up and also to get shipment means expensive courier costs from that dealer for me whereas i have a dealer in spitting distance where I dont have to pay delivery charges. If my local guy starts getting Klimas I will give them a go for sure.

I am going to derail the Klima motors thread and go back to talking about the Natter build at this point

As already mentioned as all of the wings and fins are pre-cut card the wing and fin assembly process is quite fast.

Here's the second wing going on and a couple of pics of the Natter as it stood after adding the wings. Wings were glued on using Yellow Wood Glue (Titebond II) and then filleted using the same.

Wing alignment was pretty good with the port wing showing only a small deviation from the starboard which given the non symmetrical nature of the tube was not bad.

Next up the elavators were added - these were done in one go, both together and glued to the stabiliser with the TiteBond II Aliphatic glue. Once dry they were filleted. I ignored the Noris dimesnions and went with my own as the Noris dimensions would have had the elevators set at a fairly sharp angle (The way the elevators would be if the pilot was pulling back on the stick which is about the same as the firts and only manned flight of the real thing).

After fitting these the tail fin seemed to have become more flexible - I had the same issue with my Fire Lily and its just because the flex when you feel the elevator and push it up and down seems excessive, flex in the horizontal elevator to vertical fin and flex between the body and the vertical fin makes for more flex overall - double the flex in fact. On Fire Lily I had this and tried various things to stiffen this and nothing really worked but she flies ok so I am sure this wil be fine but just to be on the safeside the vertical fin will be given a fillet of epoxy later on.

Heres the elevators being fitted, a pic showing the pretty fair alignment of all the flight surfaces plus a couple showing the state of play after fitting.

The dorsal fin was done in a bit of a rush. I was tired and rather than try and put some sort of jig together I thought I would wildcat and do it by eye using 'Gorilla' CA glue and wonder of wonders it worked great - both the glue and my eyeballs and the dorsal fin went on in perfect alignment.

I knew I would end up using CA at some point in this kit.

A word of caution here - its not good with this kit to wildcat it because there are so many traps for you later on - building on the fly with this would be like running across a minefield and hoping you wont get hurt.

Also because of the un-roundness of the body and its irregular shape you need to keep checking alignments. The firts vertical fin went on looking great. It was only when I looked at the bird from the back and test fitted the dorsal fin I could see alignment was off centre with respect to the motor tube. From the font and each side it looked ok. Not getting that right would have created a lot of heartache later on.

Anyway heres the dorsal fin on the bird so that almost the entire main body element with flight surfaces is completed.

Penultimate bit for today.......fitting the launch lugs. These were quite swinsih to do.

The Gorilla CA did a fine job on the doral fin, it was handy because the fins root was a bit skewed and the rear body is not very uniform along the seam despite a lot of patient work. The CA worked well as I could put some pressure on and get a good join all the way along and the Gorilla glue stuck card to plastic with no problems. I was so enamoured of the Gorilla glue I decided to use it to glue the metal launch lugs to their surfaces. It did a good job on first inspection but when I applied some pressure to the launch lugs the top layer of paper sheared away so I ended up rubbing some CA into the area where the lugs would go before a second attempt. That seemd to fix the problem but just to be sure each lug will get an epoxy fillet later on.

The lugs are also awkward because you are mating two lugs to surfaces in a different plane, one vertical and one horizontal. I used a launch rod held to the body with elastic bands, slipped the lugs over the launch rod and then very carfully dripped a bit of CA onto the lug and pressed it home making sure none of it got on the rod. You dont want to try and fly a Natter with a launch rod permanantly attached to it.

I did the rear lug first and then the nose once the rear lug was on and firm - once again the marking up of the body tube proved useful to make sure the launch rod was true to the tube when getting the lugs glued down. Heres some pics of the rear lug with a launch rod (this was done after fitting just to give you an idea.

Note: You can see the front lug is slightly off of the centreline - this is due to the offset introduced by the rear lug being on the dorsal fin - the offset is caused by the thickness of the fin.

Final update for today - heres the rear fins (dorsal and vertical stabiliser) getting a hit of epoxy down the root. This wil help close upo any gaps and hopefully give the fins a bit of extra grip and rigiidity. For this I used a very slow epoxy thats quite liquid and takes 16 hours to cure !!!!

Its done a good job, hard as glass and very smooth.

Next update will be the boosters but it may take some time

Phew ! Its been a busy time getting the Natter built and its often been a very slow process too. Thoughts ? Its been a toughie for sure but not in the way I expected. I assumed the vacuform would be the hard part but in fact thats been quite easy - patience and a steady hand with the glue bottle pretty much handles that. The tougher element has been to get stuff on straight. If Norris improved the centreing rings this kit would be a lot easier, they are the single thing which causes the most grief. The cause the tube assembly to be harder than it needs to be (they could thrown in some fibe centreing rings to help and adapt the build as per my ideas in the thread) the Noris rings also cause problems with marking up and alignmnet of the flight surfaces later - a little more precision there would make this kit a lot easier to handle. I suspect it would still be a tough one to make and heavy on glues. I would rate this as about the same skill level to build a TLP kit and tougher than the Fliskits Thunderbird which is probably one of the most challenging kits I have built (bear in mind I am a relative novice at this myself).
Despite how that might sound I havent been unhappy but it is a real builders kit this one so if as Dadysabr said you are not comfy with having to do your own thinking, expect the manufacturer to have worked it all out to .00001 precision, cant handle multiple glues, multiple materials ranging from plastic to papier mache, and want to buy something you can make to fly tomorrow this kit is definitely not for you.

Astro-Baby said:

Adrian...its not that bad really. Anyone who can scratch build like your stuff shouldnt have too much trouble. Iw as going to scratch build a Natter eventually but after I saw Daddisabars one i couldnt resist. Your stuff looks a lot more complex like your RheinBote and Thunderbird scratches.

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Thunderbird was quite complex but apart from its first stage, Rheinbote was fairly basic. It would be practically light relief compare to your Rheintochter!

Its not very scale by the way, body is too long and the wings are too stubby and the canopy seems to have the wrong profile so its definitiely sport scale. I would love to have a go later on at one that would glide back after ejecting the motor.

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There are photos of an early prototype with a longer nose more like the one in the kit, though that one has a ventral fin more like the dorsal fin minus tailplanes. The wings are probably a bit undersize because fully accurate wings would require even more nose weight. You could saw the front off the nose, fit a transparent cap, and fill the nose with short pieces of sharpened wooden rod to depict the R4M rockets.

If the end caps for the boosters are too much trouble, perhaps you can find something else more suitable. For one of my scratch-builds I needed hemispherical end caps for BT-20 (about 19mm outside diameter). What I found came from a little bead shop which is probably more intended to cater for makers of necklaces, bangles etc., and whose owner probably never dreamed that a couple of wooden beads would be sawn in half and put onto a flying rocket. :lol: The same project also needed a hemispherical cap for BT-60 (about 42mm outer diameter), which came from a practice golf ball. (Mainly because I couldn't find any table tennis balls on sale except by buying the whole set including bats and net, none of which had any practical use in any rocket I could think of. )

Astro...I think she is turning out great so far! you are doing an awesome job with this thread!

Thanks NJR - Adrian I think Noris make the nose so long to allow the noseweight to get as far forward as possible. A quick lash up for a test indicated she will need a LOT of noseweight to bring the CG to the leading edge. How much I cant say for sure as my micro scales packed up but I am guessing something like 60gm minimum. She is going to be one heavy fat bird. I am off at the weekend to get some lead shot. The beads are a good idea - wish I had thought of that before I spent ages filling and sanding.

By the way I am going with a single chute for this - twin chutes may be more pleasing but it means more walking too and I have an iffy foot.

Anyway ......onwards with the boosters as they are about the only major component left undone now. After several rounds of filler, sanding, filler, sanding, filler ad infinitum I concluded that the booster nose caps were as good as they would get and I had no more realistic prospect of getting them any better than I have of flying on a Soyuz. This is what they ended up looking like.................