100% scale Ruhrstahl Kramer X-7

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neat, never seen or heard of those, post lots of pics!
 
Its coming now :) , 7.5" diameter and very short bird.

Airframe mockup ready. Fits a 20 inches contrail hybrid casing (shall be an H300). I must keep the weight at approx 10 pounds, without reload and gaz to fly properly.

The picture distorsion do not really reflect proportions. More coming soon: the wings...

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OK moving forward I changed my propulsion choice. It is going to be a 20" 38mm contrail. The H300 motor. Goes thru the whole rocket and vents at top. At apogee rocekt will separate in the middle. The top part of airframe will slide along the MM, which is only glued on the bottom airframe. Single Deployment of course. This is only a crowd pleaser, like the X4, altitude is not really important.
Wings are cut and TTW the lower airframe. Wings will be glassed with CF + FG in vacuum.

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One of the coolest projects I've ever seen on here! How did you ever find this historical missile in the first place?
 
Now working on the wings: profiling, sanding, 2 layers FG, one layer CF...and in the vacuum bag for 10 hours...
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OK, the 2 wings came nicely out of the bag, just perfect ...
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next was carefully cutting all edges and sanding very smoothly the profile...
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Finally I cut my 2 centering rings..with the inside alignement jig *lol*
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...let see how it goes tomorrow by gluing all together with the MM inside the booster...
 
Those are some great looking wings. There's just something sexy about carbon fiber.
 
I copy you captain, carbon fiber is a dangerous material for your health whilst handling it..but so much sexy once ready...
Here the booster concept partially assembled...there is still something special to come..later :)

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First of all thx for the nice comments, of course it is always appreciated and a great reward for spending lots of time posting instead of building *lol*..
Now the rocekt is looking really good with his CF wings, all pieces fit well...but I understand it looks more and more like a bird now *lol*...
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And now the little surprise: the X7 will be flight-stabilized with the Eagle-Tree Guardian, 3D inertial Stabilizer ...it is clear to me that the bird was configured as a plane basically, flying horizontally to hit some soviet tanks. We cannot do that of course so in order to fly perfectly in the vertical, I was looking for an appropriate electronic device...and it just arrived yesterday from the US, I am really excited to get that part with all commands in the build...I got really inspired from this thread of the TRF ....more details coming soon!
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Wow this project just gets better and better! Thanks for taking the time to share it with us, it's very interesting to follow your progress :)
 
Guy, you would better not know what **** storm I got in the past 48 hours in Germany on this project ... because of the Eagle Tree Guardian.....Obviously the spirit of the rocket scene in the USA is much more convenient for my projects, my way of life. I want to share with friends that have fun building and trying new journeys.This is how I learn in life.
I like the American sense of enterprise and your positive attitude.

Therefore I will continue the thread only here...and I will fly the bird in another country than Germany. And I would give Chuck right: the best is simply to ignore the frustrated and destructive posters....

Now back to the topic: I cut the 3rd slot in the booster to slide the tail piece. I added the appropriate guide on the inside of the top bulkhead to center the tail against the 2 wings at 90°
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Now lets have a look at the assembly without the airframe: you will discover the structure with the wings and the Avbay, which will be placed between the front centering rings
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And now the same view, with the aiframes. I placed a piece of aluminium "U" profile on the tail just to give a better impression of the overall picture. THe real tail will be a carbon fiber tube. Stay tuned...

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Sorry you getting grief about this project. It is amazing cool and ambitious, and thanks for keeping the thread going here.
 
Sorry about the crapstorm. Some people are so clueless. I think this is an impressive and incredible project!
 
Guy, you would better not know what **** storm I got in the past 48 hours in Germany on this project ... because of the Eagle Tree Guardian.....Obviously the spirit of the rocket scene in the USA is much more convenient for my projects, my way of life. I want to share with friends that have fun building and trying new journeys.This is how I learn in life.
I like the American sense of enterprise and your positive attitude.

Therefore I will continue the thread only here...and I will fly the bird in another country than Germany. And I would give Chuck right: the best is simply to ignore the frustrated and destructive posters....

Do they understand the difference between active stabilization and active guidance? Very interesting build BTW.
 
Going forward on the construction chapter I had to think longer on the way the rocket will separate at apogee. In fact the Motor is longer as the rocket. The Payload is just an NC with 4 inches of tube in addition...so my solution look this way: I will use not one but 2 MM, in a telescope system.

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This will avoid any trouble at ejection, a smooth sliding and chute liberation. Well ist is the plan at least :)

Here some views how it fits together.

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The NC MM will be stabilized inside with an adhoc piece of wood (getting glassed with the MM later this week). This represents now exactly my payload bay. The chute will be wrapped around the "NC MM" piece at the ground prior flight.

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the booster will slide into it. Here you can see the access to the avbay by the way.

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All in all not that much place...but enough for a small altimeter, the stabilization electronics (if I use it) and the harnesses :)
 
Do they understand the difference between active stabilization and active guidance? .

Yes they do!

I do not want to interfere with this nice thread, but have the feeling, that I must say a word about the "**** storm".

We all like the projects from Denis, they are all fabulous and fly well. His launches are always great and he always tries to push along with new things.

But this particular rocket was designed as an instable rocket. In fact, the design was chosen to force this rocket to roll along the flight axis, with a gyro on board which steered the one existing control vane as aileron or elevon, depending on the quadrant the rocket was rolling into! Strange way of steering, but it was used. So this one is inherent instable, some of the german model rocket builders had doubt, that it could fly stable by itself, me too.

So the idea using a Guardian was a good one. But...you cannot expect, that it flies out of the box, it needs trimming, and also a neutral or (much better!) a stable rocket. Now guess how you trim a guardian on a large rocket at its first launch. It will not work that way, normal operation of the box is to fly up with a plane, and then switch it on in safe height. If it over reacts, you can switch it of. Something not possible in a high power rocket launch.

We are strongly concerned about safety at launch events in germany, just for a single reason: We had a bad accident a few months ago, which the government already uses to prevent rocket launches.
Since we do not have unpopulated areas here, we need to be sure that all rockets fly safe, every LCO has to be sure of that before he sends a rocket to a pad..

Therefore we made an easy proposal to Denis: Build this rocket in small, from paper tubes, launch it, trim it, if it flies, fine, make the big one! If not, better leave it on the ground.
That is not a **** storm for me, but in fact one of my primary tasks in rocketry, as a TAP member, I am supposed to help others in flying their rockets safe.


Very interesting build BTW.

Me too!
 
I think this is a wonderful subject for a flying model rocket and can be made to fly safely by just following the basic rules. Does it seem reasonably stable give the measured CG and estimated CP? Can the motor lift the weight? Is the overall drag not too asymmetrical? Are the launch conditions and hardware right? If yes then press the darn button! Make sure everyone is prepared for the worst and chances are everything will be OK.

One way to get more RSO love is to get out some LPR paper tube, nosecone (Baby Bertha!) or old TLP kit. Stick in a D12-3 with lots of nose weight and fly it scale. Fly it with a larger tail surface and less nose weight. See how it flies on small composites. Now the hard part is translating that LPR experience into a completely different, big high power model, especially with a hybrid. Can you sim it on a computer? That is just another tool. Active guidance, will it help or hurt? Good question and I commend you for trying it out. Maybe use it after a successful fixed launch to quell the fear. Is jumping through all these fear mitigation hoops really worth it? That is a question only you with your experience and high level of credibility can answer.

I always take my crazy stuff in primer to the club launch for a preview and input, now this is a lot smaller stuff than yours with local, bi-weekly club launches. I use the good scale there to get a final loaded weight. I let everyone handle it and ask for input and what it would take for their seal of approval. We all joke around a lot with mind sims, play Devil's Advocate, and suggest refinement or potential problems that might have been overlooked. So far this ancient Greek dialectic method has worked with out one Roc Sim. Gaining experience and confidence to move on. Go for it! My money is on the Ruhrstahl Kramer X-7.

Just like fear of high power inhibited NAR in the early days, big oddrocs are in the same boat. Obviously unstable HPR oddrocs made to crash for the camera have not helped. Inexperienced flyers way overstepping their skill level has not helped. Be part of the solution, not the problem.
 
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