Rheintochter / Rhine Maiden

[Cookie the Dog's Owner]

If anyone knows an ace website (ideally free) that can run cone patterns off I would be grateful.

Here's one: https://www.delorie.com/rockets/transitions.html

And another: https://www.payloadbay.com/index.php?page=Tools&action=TRANS

 

[Astro-Baby]

Cookie - thanks for that - the firts link produces weird results but the second one works like a charm - I spent ages yesterday trying to fin a decent cone calc and in the end decided while I was messing about trying to find one it might be faster to just do the math Useful learning experience though. I learnt most web cone calcs arent wortha cup of cold spit Ok if you want a party hat but pretty useless for anything else.

Sigh - if only I had access to a decent CAD system these days.

 

[Astro-Baby]

Another day in the Reich (at least thyats what it feels like building this thing ) and here we go with another round of cardboard and paper cutting fun.

The transition in paper are the hardest part and I have had to print and cut out wuite a few to get it right. My original tech drawing was out a bit on dimensioning and of course the template tool above doesnt cover thickness of card etc so I am still prototype the transitions. Heres the second nose transition prototype.

The nose cone is a spare from a Fliskits Thunderbird - the real cone has yet to be made up.

 

[Astro-Baby]

The next item to be made up is the upper body skin -part of what would be the sustainer. I was dreading this because it has so many cut outs and I really wondered if it was even possible to get this to work. As it happens it is.....

First off a 4 1/2" length of BT70 is cut out - like the lower body (booster) outer tube this was then given some BT70 to BT60 centreing rings and a tube coupler was cut in half and pushed in to keep the centreing rings square and provide a lip for the paper transition cones. The depth of the tube couplers is not critical in this....apart from the fact that if pushed too far down they will interfere with the tube cut-outs for the nozzles. Throughout all of this project I made a marking on the tubes to alert me to which end was to the front - its quite critical and useful to make sure that home cut tubes which may be a but shonky are always covered by transitions or in non-critical locations.

Heres a pic while the glue was wet - each of these after the tops and bottoms are glued in was given a second hit of glue and a long taper with a cotton bud on top was run down to get some glue filleting on the back of each ring.

Dimension Data - BT70 Tube 4.5" long with two BT70 to BT60 centreing rings at each end - 1 BT70 coupler cut to half size and pushed down inside each end of the tup leaving a lip of approx 1/8" inch

 

[Astro-Baby]

The upper body tube was then marked up, 12 lines, 6 for fins and 6 for the booster nozzle cut outs plus a line for the tops of the booster nozzle cut out. Getting this right was much harder than I had though. The tubes size made for a 14.87 mm separation and I had to make up a lot of marking guides before I got one that was right.

 

[Astro-Baby]

Next I ran off some elipse templates using MS Powerpoint - these are 26mm in the long axis by 12mm in the short axis. Each one was stuck to the tube with sellotape and then cut using a very sharp knife - my thumb will testify to that

The pic shows one cut out done and another being prepped.

Dimension Data - Elipse is 26mm by 12mm

 

[Astro-Baby]

Home free - the cut outs are all done. Putting the centreing rings in first was a must to keep the tube rigid enough for cutting.

After the tube was done though I felt it could do with some strengthing as the forward fins sit in between the nozzle holes. So I used a small band of BT70 tube with a small cut out to push into the completed body tube and glued it into place for some additional strength immediately above the cut outs.

Pic shows the finished tube plus a pic inside to show the small strengthening band.

 

[Astro-Baby]

inally a few pics I thought might be useful for anyone doing this stuff - these were taklen at an earlier stage of build while I was double checking my thinking.

Thyese show the relationship of the BT55, BT60 and BT70 tubes, the assembled tubing minus transitions and the (almost) assembled body minus the centre body wasp waist transitions.

 

[Cl(VII)]

Wow! Very nice progress, and your drawings/plans are nicer than my rockets.

 

[foamy]

Great construction and thought process.

I'm just wondering how paint is going to cover up the permanent marker. I'm probably way out of date.

 

[Astro-Baby]

Wow! Very nice progress, and your drawings/plans are nicer than my rockets.

All hand drawn with a basic high junior grade geometry kit. i did techical drawing in high school even though I had to kixk and scream to be allowed to do it. Girls were expected to do sewing and cookery classes back then !!!

 

[Astro-Baby]

Great construction and thought process.

I'm just wondering how paint is going to cover up the permanent marker. I'm probably way out of date.

Normally the so called permanent marker slowly rubs off. No idea whay it does that on rocket tubes because it doesnt on anything else. In any event a hit with some primery usually covers over it fine. RT will most likley be painted a flat green when finished so it shouldnt be hard to hide anything showing through.

 

[adrian]

I've been away for a while and have just returned to see this. Wunderbar, wirklich wunderbar!

There's a very easy way to get a wood finish on your fins if you're going to laminate them. Print a wood grain image onto the paper first.

I don't know what colour the Rheintochter would have been painted if it had gone into production, but some other missile prototypes - including Rheinmetall's Feuerlilie - were painted overall light blue. So if you would prefer a simple single colour scheme, that might be appropriate.

 

[Astro-Baby]

Adrian, inspired by you and your Rhinebote i was priginally going to do the fins in wood color with a stain and a silver body as in that sort of scheme it looks a bit 'First Men in the Moon' but I will almost certainly paper the fins and have pretty much decided to do it in a dark Lufwaffe green, maybe two tone but probably not just to keep it simple.

 

[Astro-Baby]

Not mucg progress for a few days as I took a city break to Barcelona to have a nose around and admire the architecture of Gaudi - La Sagrada Familia is totally awesome - one of the most amazing buildings I have ever seen and for sheer blow your socks off stuff rivals any of the ancients works (and I have been a few of those in my time too).

Anyway back to my rather pathetic cardboard modelling (after seeing La Sagrada Familia everything looks a bit feeble )

The real Rheintochter has a flange at the forward end of the booster. In my original design I was going to omit this and have a smooth cone transitiuon that was flush to the booster body, my reasoning was RT would be a very draggy bird with all the fins and transitions (thats not a scientific assessment - just a gut feel) and that an extra drag point might be undesireable. After a lot of thought I decided that as I am going to such great efforts to get the forward flare nozzles right I may as well put the flange in. Luckily the forward tube coupler that had been put in for the cone could double as the flange point. A centreing ring was cut down to size to fit into the top of the coupler and glued into place.

 

[Astro-Baby]

Next up the rear cone of the sustainer (just ahead of the boosters) was run off - I tried a variety to get the sizing just right. Heres the final version glued to the back of the booster stage.

Gluing this in tunred out to be a near disaster - I had test run a number of scneraios for assembling this rocket but this one, though it worked well in a dry run turned into a disaster when done with glue....read on for more on this.

Dimension data for the final cone:
Small diameter - 41.5mm
Large Diameter - 56mm
Cone Height - 33mm

 

[Astro-Baby]

Heres some pics of the inner and outer elements aligned together to show the relkationship between them.

Going back in the thread you can see that the sustainer had different sized centreing rings. BT55 at the top and BT60 at the base. This caused a headache for assembly. Option 1 was to fit the inner core to the outer sleeve and then add the cone but I could never get the cone to be a perfect size - just couldnt - so in the end I decided to add the cone and slide the inner assembly into the back end through the cone. It worked on a dry run but one the glue was added and time was of the essence the inner core stubbornly refused to go through the cone. In the end I peeled the extreme end of the cone back a bit to get the core inside and then restuck it down. Its marred the finish a bit but I am sure a bit of filler later will cover it up.

The better solution would have been to have a BT60 core all the way along the inside of the outer sleeve and only reduce to the BT55 later on. A case of being a bit too clevere for my own good there.

The final pic shows the (relatively) successful assembly all together.

 

[rokitflite]

Amazing build!!! Just to echo Foamy's concerns about the permanent marker bleeding through, I would wipe off what you can with some rubbing alcohol and a cotton ball before you paint it. I've had that stuff slowly bleed through a paint job AND decals over a several month period.

 

[Astro-Baby]

Finally to allow for the flange at the top and the subsequently reduced size of diameter of the transition cone I added a home made piece of plywood centreing ring cut to size/shape over the top of the almost comnplete booster assembly. Rhis will act as the guide for the transition cone (or not depending on how things go )

 

[Astro-Baby]

Finally the upper body (sustainer element) is put together. The cut outs for the flare nozzles are as good as I can get. I just couldnt find any really accurate design info so have done them to the sizes already mentioned in the thread. The BT60 inner core is now glued into place against the already added BT70 to BT60 centering rings. The flare nozzles (once built) wil be glued against the inner BT60 core - the nozzles all seem slightly different on every drawing or pic of this bird I have seen so I am going to go for very shallow cones (maybe).

I cant give any accurate dimensions here other than to say the BT60 core on this sits 79mm higher than the forward edge of the BT70 outer skin while the lower edge sits 1 5/8" below.

The prototype drawing worked from the Fitters mini scale paper model suggested the upper end should be 84mm but by eye I am betting on 79mm - 5mm doesnt seem a lot but it makes a big difference to the eyeballs and affects how the cone at the front end looks by quite a bit. The Fitters paper model was only of very limited use I found in making up plans for this somewhat larger bird.

I lack any lathe type gear - the real thing has more of an ogive shape from forward of the front fins but I couldnt find a nose cone the right size and shape so am going for a gentle cone with an ogive balsa nose. Will it work out ? I havent a clue right now

Oh - final note - the inner BT60 core (assuming anyone wants to clone this) has to be long engough at the lower end to have a usable transition via centreing rings to the BT55 inner core of the booster (lower) stage but not so loing that it fouls the mid stage cone that joins the two stages together.

The recovery gear fits into the upper end of the inner BT60 tube shown here from a point just forward of the front edge of the flare nozzle cut outs. There wont be a baffle in this kit cos I forgot to order one but there will be a kind of baffle plate to stop the chuts and gubbins being forced into the smaller BT55 tube due to acceleration.

I did originally plan this as a two stager - it might still be depending on how the first flight as a single stager works out.

 

[Astro-Baby]

Thanks Scott - truth to tell I have yet to see the marker bleed through paint yet. Maybe because by the time I have handled the bird, filled, sanded, handled some more, bit more filler, two coats of primer, more sanding and handling etc most of it has worn off - its good advice though.

I wish it wouldnt wear off so quick to be honest - I am always worried a bit of marker thats essential may be lost I like lots of notes, markers, reminders etc so I dont mess stuff up more than usual

 

[Astro-Baby]

Todoay - I am mostly doing transitions !!!

Some of these took a few stabs to get right and in truth I am still not happy but there comes a time when you have to say 'enough already' and just go with it. The transitions were all done from card stock. Tip here I picked up from building the Fliskits Mako was to use a Pritt Stick to glue the transitions together with. It dries faster and is less damaging to the paper and/or card. Once the card transitions have been glued into place, hit with cyno and painted the chances the seams will part is small. The Mako in fact was the kit which gave me the idea for how Rheintochter could be made up from a russian doll approach of tubes within tubes with long paper transitions - word out here for the Mako - its a great kit to build and flys a beaut too.

Anyway - heres transition B which is the small cone just forward of the booster element. This forms part of the Reheintochters wasp waist. I suspect that in fact on the real thing this is a bell housing for the sustainer motor and separation would be on the base of this cone.

Dimesion Data:
Larger Diameter - 45.5mm
(based on the home made plywood ring - this is open to changes and could be a larger diamter of 56mm if the wide end of the cone were to fit to the booster main tube rather than having the flanged end)Smaller Diamter - 33.5mm
Height of cone - 32mm

Note: All domensions are based on the Fliskits supplied tubes - other tubes wil obviously vary.

 

[Astro-Baby]

Next up was the nose cone transition at the front end of the sustainer unit. This is dubbed Transition X in my plans as I must have made up about a dozen various sizes trying to match the transition to the main tube and the nose cone to try and give an ogive like appearance to the whole assembly. Its still not perfect but short of maching something up from balsa which is beyond my abilities this was the best I could muster.

Dimension Data:
Large Diameter - 56mm
Small Diameter - 41.5mm
Lengtrh of Cone - 78mm

 

[Astro-Baby]

Whoops misssed a step there - I was a bit stuck at one point about how to get the wasp waist assembled. With so many changing diamters and various centreing rings needed to glue it all together it was a bit of a puzzle.

In the end I settled for putting some centreing rings into the sustainer unit thse are BT55 to BT60 rings and were pushed into place using a rolled up magazine to get them square and at the right depth. The original plan had these being mounted on the BT55 but with the wasp waist transitions there was no way to do it easily.

Heres the two centreing rings inserted into the sustainer unit.

Build Data:

BT60-BT55 Centreing Rings (x2)
Depth from base of Sustainer inner BT60 tube - 15mm and 70mm

 

[dixontj93060]

Wow, lots of detail work there in the drawings and construction.

 

[Astro-Baby]

Next up is the long transition from the sustainer towards the booster - the sceond half of the wasp waisted element.

This is made up but not glued onto anything yet - I want some manuevarability when the two halves get glued together. This just gives an idea of the shape of the front end of the bird.

 

[Astro-Baby]

Last few pics for today - the final shape of the sustainer with its real nose cone - yet to be finally sorted out plus a pic of the two halves with a paper template with each showing its fins and, the massive span, of this bird.

 

[Astro-Baby]

Wow, lots of detail work there in the drawings and construction.

I suffer a bit from OCD No really I do - I like clear plans and endlessly tweak things. I used to do water colours and inks years ago but never hang anything of mine in a flat as I am always taking it down to tweak it a bit

In part I also wanted good plans in case Mark 1 blows itself to bits - I dont want to have to reinvent it all again so wanted a reliable set of drawings to replicate it from if needed.

Personally I think it will fly badly - maybe even unstably - but I HAD to give it a go ever since seeing one when I was about 12 years old at the Imperial War Museum.

 

[Astro-Baby]

And this really is the final load for today as I am whacked out

As the upper body (sustainer) centreing rings dried quite quickly I decided to glue the whole lot together. High stress momensts here as both rings had to be glued PLUS the transition cone plus I had to get the shock cord in. The shock cord has a knot in it and is jammed againts the lower centreing ring in the upper body. To pull free it would need to get under three glued in centreing rings so it pretty secure.

Knowing haw fast aliphatic glue can go off and jam things I used Titebond Yellow for this stage as it tends to be a bit more forgiving and allows a bit of repositioning.

Heres the final thing assembled in two pics with its plans which are now starting to resemble the score to the Rites of Spring overlaid with a copy of War and Peace in three dimensional holographic design as visulaised by Paul Klee

 

[Astro-Baby]

And very, very finally - mindful of the gap between the BT55 and BT60 tubes inside the bird and mindful that that gap could provide a trap/jam point for the recovery gear I had decided to put a restraint ring in to both hid the gap (which is internal only) and to stop the recovery gear being forced into the narrow BT55 tube. This was rammed into place at the top of the BT55 inner tube with the Mark 1 rolled up magazine and finally given a fillet of glue.

The shock cord (kevlar section) runs between this and the BT60 tube wall - further down its trapped between the BT55/BT60 centering rings which hold the BT55 to the BT60 so its well stuck and, knowing this sounds like famous last words, I think it will be hard to dislodge.