Rheintochter / Rhine Maiden

This is the sustainer/upper body being given some detailing. A wrap around (though it not as its in 6 sections ) was added, plus strakes and finally some filler/blending to try and give it the look of the original. All this detail did not add any significant weight - I was keeping an eye on it on the scales.

The upper body panels had always been an option and they were under consideration since the build began. I decided to go with them partly from detailing but also because the flare nozzle holes in the upper body were not quite right and having a wrap over them allowed me to refine the shape a bit better.

After the first filling and sanding to rough all of the fins plus the body wraps and strakes were given a hit of CA which has made the whole thing a lot more rigid.

Like the rear strakes the forward ones had holes in them to start with but I didn't like the Meccano look it gave so filled them in.

One of the curses of getting in close with a camera is it makes the finish look dreadful. Actually to a finger touch its quite smooth.

The flare nozzles were an enduring piece of aggravation to try and get them to look right, not necessarily to scale but to look 'right'.

These probably consumed more time than almost any other aspect of the build.

The final solution was to create the bases by wrapping some card round a dowel. Steaming the hell out of it and then gluing it to create a kind of mini-body tube. Once the glue was dry the tube was cut to the required length and an angled cut applied for the join to the inner tube of the sustainer. To cut them I simply pressed them flat against a template - and here's the clever bit - they were then misted with water and put back on the dowel and dried with a hair dryer while being rolled about. This allowed them to form to a perfect (or at least near perfect) circular shape.

The cones themselves are very shallow - I will give details later if anyone is interested. These were bog standard construction from card, rolled around a knitting needle and glued. They were not attached to the bases just yet though.

Looks easy - and it was once I had the right dimensions - I must have made about two dozen versions of these as a background task during construction. The advantage I saw in a two piece nozzle was that if a base was glued on slightly off - any errors could be corrected by adjusting the nozzle a bit when it was glued to the base - it worked well.

Heres some pics of the nozzle assemblies.

Finally - the flare nozzle bases were glued to the inner tube of the upper body. As the contact surfaces were quite small each was initially taked into place with a small amount of aliphatic glue. Once dry a piece of kleenex soaked in aliphatic was pushed down the base to provide a plug that contacts the inner tube wall and the sides of the nozzle to provide a nice solid fitting.

Once all was dry the upper nozzle was glued into place and the whole assembly given a splat of CA.

The pics show the nozzle base fitted plus one of the completed assembly.

The motor was fitted in a moment of forgetfulness (I have flu at the moment) and was pottering about. I had planned not to fit this until I knew the all up weight but its too late now - a trim ring was added to the base of the motor to give it a flush finish to the base of the bird. The actual motor itself will protrude slightly. I toyed with the idea of having it more recessed but I have a rocket that has that and its a pain to extract engines from it.

Meanwhile the nose was given some detailing - these are the simulated pressed panels that held onto the wooden canards on the real thing. Not very happy with these personally and wish I had down what I planned and glued a half dowel on first to give these the more bulged appearance of the real thing.

Finally the completed bird - Rheintochter R1 (the AB version ) - all it needs now is a bit of finishing, nose weights, recovery gear - oh and some paint. I am planning a camo pattern for it.

Thanks everybody for contributing and for your kind words - I feel embarrassed really as I am bit of a bodger in truth and if you saw it close up you would probably run out the room screaming. Makes me feel a fraud

Also - if you have asked something and not had a reply or suggested something and been ignored - my apologies - I probably missed it in the thread. Having been a bit busy my time is so limited I sometimes scan read stuff and miss things so please don't believe I am being rude or anything.

That's looking very good. Gonna take a good bit of sanding and finishing, but it's all part of the process. Though, honestly, it has a "shop" kind of charm as it is in it's raw state. I'm impressed. It's a work of art as it sits.

Groans at the thought of sanding - eewww just dont like it. Roll on cheap 3D printers

I got asked for the plans I worked from for this - well if you want them you'll have to pay me about a million dollars OR offer to sand the bird to perfection for me
Seriously I was going to upload them but the PDF files are too big so if anyone wants the templates and main schematic hit me up on PM and let me have an email addy and I will forward them to you. The whole set is about 3Mb so make sure your inbox has enough space

Things I would do different if I were building again.....

Plastic nose cone - easier to add weight thats assuming I could find one that had the right profile.
Buy a dremel - it would have made cutting the flare nozzle holes a bit easier.
simplify the inner tubing of the bird to save a bit of weight. I was a bit extragavant early on in the build.
Lengthen the nose section and shorten the wasp waist - inadequate research there led to a bit of a change of proportion. A longer nose and the forward fins set further back might have helped with the CG/CP thing.
I'd probably omit the fin strakes next time round - they make her look ugly and it would save a small bit of weight.

I did some calcs and experimenting today which leads me to believe that even at max nose weight the CG will be at most about halfway along the root of the forward fins. Any more weight and she wont get off the pad. She's only 23.5" long but she is a very heavy fat rocket. I may try her slightly shy of ideal in the balance department and see what happens. She is still lighter than my SLS Hustler and that can get up on a D12-5 - this one will be having a D12-3 as I have a plentiful supply of them. Quite surpising really how heavy she has become.

I now have a week or so of sanding and fiddling about to do.

Love this rocket. For fun I tried making an Open Rocket simulation. I had to guess at the nose and the fins, but I think it is close.


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Astro-Baby said:

Finally the completed bird - Rheintochter R1 (the AB version ) - all it needs now is a bit of finishing, nose weights, recovery gear - oh and some paint. I am planning a camo pattern for it.

Thanks everybody for contributing and for your kind words - I feel embarrassed really as I am bit of a bodger in truth and if you saw it close up you would probably run out the room screaming. Makes me feel a fraud

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Welcome to the bodgers' club! Many of the rockets shown here probably would not survive close inspection, certainly all mine - if yours make people run screaming then mine probably belong in a Hammer horror film. :lol: This is partly because I'm lazy, partly because if I put too much effort into a perfect finish then I'll be terrified to launch the thing, and partly because the first encounter with the ground at our launch site, even assuming perfect recovery, will leave marks that will make the whole effort a waste of time. (Our launch site is practically a marsh. The advantage is that most rockets will survive non-optimal recovery deployment. The disadvantage is that they'll get dirty. There's also only one tree for miles and nobody has managed to hit it yet.)

This is probably a stupid question but I have to ask for my own peace of mind. You are planning on fitting a launch lug or two before painting, aren't you? Unless it's already done and I missed it among the earlier reports.

Well I was going to pass on the launch lug and just fire it off while its sat on its fins at the back - I feel the launch wil be more exciting that way :surprised:






Just Kidding -:dark:





I havent fitted them yet thanks to me forgetting to order any. I am planning to make some up from a straw as soon as I find a straw the right size. The other option will be some thin ally tube if I dont find a straw before I find the ally tube

The paint job - well I am spending big on Rheintochter - she is already the most expensive rocket in the fleet. So I thought 'what the hell' buy an airbrush and do a nice fuzzy WW2 camo on it (maybe).

By the way here is a picture of a Rheintochter I found the other day at its staging. Its weird - a few months ago there were almost no pics on the web - or at least a limited selection. In the last few months there are dozens of new pics turning up all over the place. Wish some had been available when i planned this - a few years ago the sole pic I could find was a ropey looking RT at the Aberdeen Proving Ground in a very sorry state.

Anyway the staging pic is useful - it shows the location of the flare dispensers on the forward wings and also makes me think that the staging separation point was at the wasp waist point where the rocket is at its narrowest. The pics I have seen so far suggest this is right as the narrowest point appears to have small couplers around it which I think (from a description I have read) would have been fitted with explosive bolts.

I am planning to get to RAF Cosford later this year and they have an RT on display - I will see if I can charm someone into letting me get some measurements off of their one. I managed to schmooze my way into a sit in a Rover 200TC at the Heritage Motor Centre two years ago - I used to own an identical one back in the early 80s - so Iwll see if I can charm someone there. Didnt work at Duxford with getting to sit in the TSR2 but it was worth a try

Work has had to stop for a bit as I have some other stuff to get on with - I will be back on board sanding and filling and, if the weather gets better, painting in a week or so. So theres lots of pics to come yet as I manage to mess up the paint and then launch a scary rocket with suspect stability My youngest son wanted me to build this - as he has done just about zip in helping he can have the honor of pressing the fire button while I take cover (cravenly) hiding behind a tree

Uncle Scary said:

Love this rocket. For fun I tried making an Open Rocket simulation. I had to guess at the nose and the fins, but I think it is close.

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Uncle Scary - thats quite a bit of work - my thanks to you for that. Its really useful.

The rear fins are a teensy bit undersized but its damn close. Whats interesting is I started doing the math but kind of fudged it because with all the transitions and weird shapes it bacme nigh on impossible for me with only a small, basic budget model, sized brain
(I cant run stuff like Rocksim etc because I only have an ancient 14 year old PC and frankly most programs just kill it dead - trying to get most stuff to run on it is hard work. I only use it these days for pic editing and web authoring - enough of my woes to be sure )

Anyway whats interesting is I despaired of finding the CP and in the end used the old two dimensional paper model approach printed onto card. You can see it in some of the pics of the build in the background - the last pic for instance - is a two dimensional Rheintocher printed out in small scale based on downscaling the model by a factor of about 3 - its almost identical to the Fitters outline for the mini paper kit (now that IS fiddly - I gave up with it ) but its slightly changed to suit the altered dimensions of the big kit. That gave the CP at almost exactly the same point as on your simulation. I estimated the optimum CG as being around 2 cal which would put the balance point at about the centreline of the flare nozzles but some messing about with weights to try and get the weight as low as possible but still acheive a CP/CG of around 1 cal worked out at just aft of the trailing edge of the front fins - almost exactly the same as your simulation.

Its good stuff as it kind of backs up my own thinking but yours is scientific where my thinking is prone to being wrong (lots and often )

Thanks though for all that work - its really useful to stuff and I am sure other builders will also get some serious use from it.

ps if you want the paper plans hit me up in PM with your email addy and I will send you the PDFs of the plans.

Astro-Baby said:

I havent fitted them yet thanks to me forgetting to order any. I am planning to make some up from a straw as soon as I find a straw the right size. The other option will be some thin ally tube if I dont find a straw before I find the ally tube

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Straws can work, but beware - some of them are horribly difficult to stick because glue does not hold on to them. The worst case scenario is that they hold long enough for you to paint the model, then fall off the moment you put it on the pad. A useful trick which I learned some time ago is to put a wrap of paper masking tape round the straw, then it will stick much better. I haven't had a drinking straw launch lug fall off since learning that.

Anyway the staging pic is useful - it shows the location of the flare dispensers on the forward wings and also makes me think that the staging separation point was at the wasp waist point where the rocket is at its narrowest. The pics I have seen so far suggest this is right as the narrowest point appears to have small couplers around it which I think (from a description I have read) would have been fitted with explosive bolts.

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Could be. That photo I posted of the sustainer lower body shows the wasp part ending in a flange with holes, possibly where it would have been bolted to the booster. The lower part of the wasp waist would then have remained attached to the booster after separation. The photo also appears to show the couplers and bolts, in line with the flare nozzles. Having said that, I might be inclined to built the whole wasp waist onto the sustainer so that the booster and sustainer by themselves would look as the real things would from the factory. I did that with my SA-2 - again, there's a part of the sustainer which is bolted to the booster and which stays with the booster after separation. I built it onto the sustainer so that the model looks accurate before launch. When the rocket is in the sky, it would require really good eyes to notice that the sustainer is not quite accurate after separation.

When the rocket is in the sky, it would require really good eyes to notice that the sustainer is not quite accurate after separation.

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I usually like some video of my launches mostly because I miss most of them - my eyeballs take so long to start tracking the thing is back on the dirt before I ever really get a good look

Guys,

Major disaster with RT. I have now acquired some lead and lo and behold even with the bird weighted to the eyeballs, balsa nose cone drilled out to make space for a load of lead (115 grams worth to be precise) this bird is still back end heavy. There is no physical space to get more weight in and with 115gm noseweight she is still shy of the ideal CG by a bit - with max weight in the nose she hits the scales at 350gm of weight and the CG is around 2" forward of the CP (about 1" behind the trailing edge of the forward fins).

It seems I have no choice but to cut the nose off the Mk 1 and lengthen its nose to try and get a bit more moment. What do you reckon ? Am I mad or would it be better to test fly with a less than ideal CP/CG relationship ?

My gut instinct tells me fly the bird as is with thge 155gm and see what happens. Worst case is she is destroyed and I get to build it all over again but get some stuff bettwer worked out next time.

Personally I just cant see why she is so back end heavy, the rear fins are no more weight than the front end fins and the tubing is about the same at both back and fore ends.

Trust in thrust. Now raw power is now the only cure for the RT. Less than ideal CP CG relationship is OK. Keep the weight down because you are limited to a D12 3. I think it has a 15 oz. max lift off weight. Long and strong quarter inch rod, give it some time to get fully up to speed before leaving the rod, inertia is your friend. Launch in calm conditions only. Pray. Be good and avoid the Dark Side at all costs. More prayer never hurts. May the Force be with you.

I updated the Open Rocket simulation from the plans you so graciously sent me. With 4 ounces in the nose and a D12-3 motor installed, I get an overall weight of 12.7 ounces. The CG is 10.34” from the tip of the nose cone (about 0.4” ahead of the trailing edge of the fins). Stability is 1.58 calibers.



I have to add about 1.5 ounces to the tail of the rocket to get the CG to 1” behind the trailing edge of the fins. Even with the extra tail weight the stability is still 0.9 calibers.



I think you'll be OK. Pray for no wind and use a long launch rod.

Astro-Baby said:

By the way here is a picture of a Rheintochter I found the other day at its staging. Its weird - a few months ago there were almost no pics on the web - or at least a limited selection. In the last few months there are dozens of new pics turning up all over the place.

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1) Pls pls pls--- give us some links about the new pics you mean. I am completely astonished with this pic I never saw before. Every new picture/link from the real thing is appreciated..you already know what i am going to do with it ) *secret*

2) I would not be so scare on the CP issue. The fact is simply that the amateur Software we use are not precise enough for calculations of complex aerodynamic of such birds. The big KRAMER X4 I built (posted on TRF) was said to be nearly instable. It flies like a laser beam upwards! My view is that the huge drag of the fean is going to bring the CP far behind the predictions of the tools we generally use...

Denis

Legrandudu - the pic of staging was gathered from the web just by doing a Google search for images. Whats spooky is everytime I do another search recently more new pics I havent see before fly up.

About 2 years ago I did some research on this and pretty much the only pic I could find online was the one below. Even since I started this project more and more stuff has come up.

The one below was stated as being at the Aberdeen Proving Ground USA and it looks as if its in a pretty sorry state although interesting, as I surmised in an earlier post, it does show a cable tunnel alongside the lower fuselage rather than just a pair of wired tacked down with cable clips. Its also shows the flare pods at the ends of the forward fins.

The pic below disappeared fro some time off the web and its taken til now to find it again - it was on an old harddrive that failed some time back so a lot of reference pics I was gathering simply vanished.

Astro-Baby said:

Guys,

Major disaster with RT. I have now acquired some lead and lo and behold even with the bird weighted to the eyeballs, balsa nose cone drilled out to make space for a load of lead (115 grams worth to be precise) this bird is still back end heavy. There is no physical space to get more weight in and with 115gm noseweight she is still shy of the ideal CG by a bit - with max weight in the nose she hits the scales at 350gm of weight and the CG is around 2" forward of the CP (about 1" behind the trailing edge of the forward fins).

It seems I have no choice but to cut the nose off the Mk 1 and lengthen its nose to try and get a bit more moment. What do you reckon ? Am I mad or would it be better to test fly with a less than ideal CP/CG relationship ?

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If it is reasonably practical, I'd lengthen the body tube. As well as giving you a better CG/CP balance, it would make the model look more accurate. Given all the effort that has already gone into this, it would be a shame for the model to be destroyed on its first flight when some pre-flight surgery could save it.

I Adrian,

I did look at lengthening the bird but it proved to be potentially very troublesome. Interestingly I got a pic off the web with the real thing in flight taken almost exactly side odd, possibly a still from a film as the quality was not good (see below - this pic is quite common but most appear to have been heaviliy retouched - this one looked more authentic to me), I printed it off and measured it up and the forward body element was basivally four wing root lengths long (plus a teeny bit). When I measured the ratios for my own design it was four wing root lengths long minus a tiny bit so the deviation is probably, in terms of the model, around 1/2 to 1 ". I think what throws it out is some pics show a very straight nose section coming to an almost conical nose cone while others (and the model design I used was taken from those) show a more slow ogive nose cone. As I couldnt produce the long slow ogive I used a taper transition towards the ogive cone (which was a pain in itself to sand to a good match). Consequently I think the shortened nose unit on mine tends to be something of an optical illusion - even to my eyes at a glance when looking at the kit its hard to believe the nose is actually as long as it is. Also - I did make up a small 2D model to check where the CP might be after extending and extending the bird would push the CP further forward cancelling any advantage in the moment of balance. The final CP/CG relationship is hellish close with only around .7 calibre difference. That may be bad news but my TLP Perseus has a similarly close CP/CG relationship and flies like an arrow so I am going to hope my design skills are at least as good as TLPs (thats unlikley by the way and I am being ironic)

The pic I have of it in flight also shows a much longer wasp waist or a greatly extended booster section that appears to extend some way forward of the leading edge of the rear fins where the museum ones all appear to be a lot shorter in this regard.

Anyway - the model is now complete I will post up later a few pics.

Ah-ha - fortune smile son me - I thought I was going to have to go out but it appears not so the pics are coming quicker than expected.

Heres the bird with one of its undercoats on and finally starting to look like a model rocket rather than a pile of lumber.

Painting this turned into a total nightmare. The finish was gotten good with two coats of undercoat and some rubbing down. The initial model was painted in a GM Leaf Green which was the closest car spray I could get to a Luftwaffe light green (it actually looked more like a Russian Army green to me - at least its about the same color as a T34 tank in Bovington Museum). All was well. I then decided to add a zig zag style camoflage as used by the Luftwaffe on the top wing surfaces of aircraft - based on a flying balsa plane I made years ago of the Do335 and thats where it all stareted to go wrong. For some reason which I couldnt fathom the light coloured paint when on like a charm whereas the darker color refused to cover without multiple coats, it ran like hell, dried absurdly glossy and just looked AWFUL. To add to the misery some of the masking tape stuck so hard it pulled bits of the paper skins off the model and left it looking a mess.

In the end there was nothing left to do but add some more filler, more sanding and respray over the lot with an undercoat again and start from the top. Mindful that any more screw ups would possibly write the model off I opted for a basic camo green I picker up thats Ultra Matt. The can capo showed it as being close to a kind of grey green that V2s were painted with but on the model it came off as a rather dull and light grey green.

After painting a few small transfers were added - a CP/CG pair which shows as two dots in the pics plus some thin pinstriping left over from the transfer surround of a Semroc set ages back to simulate joins in the rocket body - one on the upper section and one at the wasp waist just to give it a little bit of definition. The final piant came out ok(ish), perhaps a little bland, but the paint in pics gives it a kind of washed out look which makes it look a teensy bit cooler.

Heres the result with a few detail pics showing a less than perfect finish after the screw up with the paint (by the way thats it for me - in future I am buying an airbrush and using Tamiya Acrylics which I have never had a problem with EVER).

The bird is finished internally with a length of kevlar tied to some nylon/elestic thats pretty strong. I made a chute out of some spare mylar I had hanging around - the finished bird fully loaded for flight weighs in at 300 grams. A nylon chute would be better given the weight but there just isn't the space in the nose - the mylar chute only just about fits in there.

She is noseweighted with a whisker under 100gm of lead in the nose held in with some epoxy.

Anyway here are the final few pics - the next ones you will be seeing are the launch video - and possibly the whole model reduced to matchwood

Awesome! Good luck on the maiden flight.

Really nice. Good luck.

Just fantastic!!!! Good luck with the first flight!
Denis

You will be fine on a D12-3. I think it looks good and accurate as is. Operationally they would have been painted with what ever they had laying around at the end of the war to avoid any shining bits attracting Allied attention.

Lovely work, as you always do. Looking forward to the flight video.

That light grey-green is not far off RLM 02, a shade of grey green used by the Luftwaffe as the base colour for some fighter fuselages as well as the insides of some aircraft. I'd say it is a reasonable colour for a Rheintochter.

Good luck with the first flight!

Damn weather has not been good, this weekend was looking good but partner is not well and neither of my kids are around go help tote the bord down to the launch site

On the upside I have progressed some way on the Feuerlillie project and I will of course do a build thread for it so anyones who interested can have a look. Lily doesnt have much on the web in the way of photos of the real thing so mine is mostly guesswork and fantasy.