Experimental Rocketry

Hello! I'm very interested in building amateur rocket engine. I've already started some hardware, but my interests lie primarily in liquid-fueled, regeneratively-cooled medium-sized engine.
My current project is HTP-kerosene approx 2200 lbs thrust engine. The main problem is that I have very little info about HTP compatibility with different construction materials, metals, plastics, etc. I know that copper is incompatible with peroxide, but I need quantitative data about how fast decomposition occurs when contact peroxyde to copper alloys. I know that tin (especially, stannates) stabilize peroxyde, but i need data what percentage tin-copper alloy is safe to peroxyde.

First test chamber will be cooled at the stand by pure water. It solves HTP compatibility problem but makes the engine only experimental and useless for flight. May be I'll find a way to cover inner surface of the tubes by tin, or may be i'll find a way to make next chamber of stainless steel tubes, but may be there are more direct ways to cool the engine by HTP.
I've studied some doc's about Black Knight and it's Gamma engines, but almost unable to collect any other data.

Help me if you have any data about peroxide compatibility!

Hello, Andrew!
And a hybrid motors? We had designed an tested a few little scale NOX/nylon hybrid motors. If you have any interest in this topic let us now.

I'm very interested to see R. Nakka here. Provided it happens I’ll be lucky!

termostat, 27.03.2004 02:42:15 :

I'm very interested to see R. Nakka here. Provided it happens I’ll be lucky!

 

Ask him any question if then!

I cannot speak on behalf of all users on this forum (as I have joined only recently), but one is sure - this forum is very active. People discuss their designs, ideas and experimental results eagerly. It's a pity, of course, that this information is inaccessible to you directly, but hey, that's why this topic was created. Feel free to ask detailed questions and be prepared to receive lots

Sorry that my earlier message was posted as "guest"...I don't think I was registered properly.
I think I am registered now....

A quick question. How popular are sugar based propellants in Russia, compared to
say, AP composite? Has anyone had success with AN based propellants that don't
use magnesium?

cheers
Richard

Briefly, this rocket hobbyists forum opened about two years ago. Before that people discussed amateur rocketry in the Space forum, and it became too specific . Since then a fair amount of experimenting with self-made solid fuels was done more or less independently by the participants. Same is true for common questions which any rocketeer faces - how to detect apogee, how to make launch pad, how to measure the motor characteristics, how to design rocket... The current, rather stable, organization of the forum is such that common topics are divided into categories, which are always on the first page of the forum - hence the discussion is going mostly about topic in hand. Usually the newcomers are expected to dig archives to find (repeated) answers to most common questions; it's unlikely that this is the case for Richard .

Hmm... I'm watching this forum mostly as an observer, since I'm more interested in liquid fuel engines. May be you, serious guys from this forum summarize the state of the art over here?

Richard, the fuel experiments - at least most successful ones, as far as I know - revolved around sugar-based propellants, and later with sorbitol-based (not sure about translation of this term ).

That's true: sorbitol - Поиск в Google

Google foreva

Richard, I have a question about kinematics. In your latest flights you record the acceleration data, which is later used to restore the flight altitude by integrating. How do you take into account that the acceleration is measured in respect to the (non-inertial) frame of reference of rocket? The accelerometer measures a-g (in vectorial form), where a is the inertial acceleration of rocket.
Do you assume vertical flight path and just add g to the scalar values of measured non-inertial acceleration to obtain the inertial acceleration, which is then integrated twice? And if yes, do you have any data on how much the path deviates from vertical?

With regard to the accelerometer data, you are of course correct, that it measures acceleration with respect to the rocket. I simply have to assume vertical flight, as there is no way to know exactly how much deviation there is from the vertical (especially when the rocket has disappeared from sight.
There will be some (acceptable) error introduced into the result. But for small angles normally encountered during flight, the error should be small, the way I see it, as the cosine of a small angle is nearly = one. Would you agree? BTW, some instrumentation systems use 2-axis accelerometers...this should allow for more precise determination of altitude (if one needs such!!).

R.

Agree on cosinus. But I cannot see how 2-axis measuring would solve the problem of measuring the deviation, as during the flight (no matter how deviated) the non-inertial acceleration vector is parallel to rocket axis (assuming that motor and fins are mounted in parallel to rocket axis). The second axis would account only for sudden wind breazes. The problem is (which so many people fail to realize) that during flight there is no way to tell the vertical direction (or the direction of g) by means of accelerometer data.
Of course, one could build a system with 2-axis accelerometer placed in the CG of the rocket to account for linear accelerations and one 2-axis in the nose to account for angular accelerations... but then you end up with really complex and possibly error-prone system
People here begin to acknowledge the benefits of magnetic apogee sensor, and at least one is already built.

I agree. What you say is true. Inertial navigation is complex stuff and beyond the scope (and needs) of the amateur rocketeer.
Is magnetic apogee sensing used to determine altitude? I know it has been used to deploy a parachute when the rocket pitches at apogee, but I did not know it can be used for altitude determination....

R.

Of course it is not used to determine altitude. My comment was influenced by the very hot discussions here about the different designs of parachute deployment sensor.
The moment when rocket pitches is a very good moment to deploy the parachute, and it works also for emergency situations in abnormal flights.

Too bad I missed those "hot discussions" on parachute deployment methods, sounded interesting

R.

>What type of rocketry is most popular here ? Model rocketry, "hi-power (commerical) rocketry or amateur rocketry? And are solid propellant motors popular , as opposed to liquid or hybrid (these latter two I am only just learning about)...

• Model rocketry was legal hobby in USSR and is legal hobby in Russia, Ukraine, Moldova, and other exUSSR republics at present.
• Hi-power commercial rocket is classified as weapon and you must obtain goverment permission for production and using such devices.
• Amateur rocketry is normal hobby now but some features are restricted.

So there are many old model rocketry hobbists, and not so many new amateur rocketry hobbists.
In USSR the only legal way to make really power rocket was to enter a aerospace department. Many universities had such departments and aerospace industry needed these graduates. As home hobby it was illegal.

So now the most popular is solid propellant motors. Liquid or hyblid projects are rare bird.

Message from Spirit of Betelgeuse:

---

Hello, Richard!

I'm always interested to read the information on your site. I'm exited about the profound approach to the topics covered there. Your site serves as the standard for sites of other rocket amateurs.

Could you answer some questions of mine?

1) Do you plan to add to SRM.XLS the possibility to design motors with different grain geometry (star-shaped core and others)?
2) Do you mind that we provide on our site the translations of some most interesting pages of your site (providing the source and the author)?
3) Do you plan to conduct experiments with oxidizers other than KNO3, for example, ammonium nitrate NH4NO3?

---

timochka, 29.03.2004 09:22:17 :

* Model rocketry was legal hobby in USSR and is legal hobby in Russia, Ukraine, Moldova, and other exUSSR republics at present.

• Hi-power commercial rocket is classified as weapon and you must obtain goverment permission for production and using such devices.
• Amateur rocketry is normal hobby now but some features are restricted.

So there are many old model rocketry hobbists, and not so many new amateur rocketry hobbists.
In USSR the only legal way to make really power rocket was to enter a aerospace department. Many universities had such departments and aerospace industry needed these graduates. As home hobby it was illegal.

So now the most popular is solid propellant motors. Liquid or hyblid projects are rare bird.

 

Thank you for the background information on rocketry in this part of the world.
This is similar to north america, except that Hi-Power commercial rocketry is
very widespread here (especially in USA). Also, solid rocketry is by far the most popular form of amateur rocketry.

I knew that model rocketry has been popular in former USSR. In fact, the most amazing and beautiful model rockets that I have ever seen (currently owned by a friend) were built by Russian modelers. One was of a Soyuz (?) booster, with working stages and strap on rockets. Incredible detail, functional too!

Richard

Дух Бетельгейзе, 29.03.2004 13:49:26 :

Message from Spirit of Betelgeuse:

---

Hello, Richard!

I'm always interested to read the information on your site. I'm exited about the profound approach to the topics covered there. Your site serves as the standard for sites of other rocket amateurs.

Could you answer some questions of mine?

1) Do you plan to add to SRM.XLS the possibility to design motors with different grain geometry (star-shaped core and others)?
2) Do you mind that we provide on our site the translations of some most interesting pages of your site (providing the source and the author)?
3) Do you plan to conduct experiments with oxidizers other than KNO3, for example, ammonium nitrate NH4NO3?

---

 

Thank you for the kind words, appreciated.
With regard to your questions:
1)My greatest regret is that I do not have enough time to do all the things I would like to do...! I currently do not have any plans to modify SRM.XLS for other grain geometries, although I recognize that this would certainly be useful. For example, star-grain and Rod & Tube. However, if someone else would like to "inherit" the spreadsheet to make improvements, I would be pleased to supply an unprotected file that could be modified.

2)Indeed, feel free to provide translations of my site. My desire in having the site is to make information available to anyone who has a keen interest in rocketry, and to learn from others, in return.

3)Interestingly, this evening I test fired such a motor...! It used a propellant formulation based on my RNX propellant (KN/epoxy) , enriched with 5% potassium perchlorate (KP). I have yet to analyse the data, but the firing went well. I have been starting experimention with KP, mainly to enrich KN formulations, as KP by itself can be quite "wild" I also plan to enrich KNDX (dextrose) with the addition of sodium nitrate to slow down the burn rate. Also, I have been experimenting with ammonium nitrate (AN) for a year now (in my spare time) to try to come up with a formulation that does not require magnesium (hazardous, expensive & hard to get). So far, the results have not been so good...the most "promising" has been a blend of KP & AN with epoxy binder. still too slow burning to be practical...needs more work

Richard

Hello, all!
Now i in Finland!

to RNAK:
Richard, this is country of you grandparents!
From Finland with my best regards!
Bye!

That is very, very interesting....(BTW, what happened in the 3rd video?)
I had been thinking about doing something similar to "force" my AN formulations to burn, but I wasn't sure if it would work. Glad to see that this method is effective. Clearly, it must have burned well to develop the pressures your motor achieved. I will have to experiment with this approach...!

Richard
=====

He-khm...
I've been visited by similar idea - to add to sorbitol candy motor one grain pressed up of black powder + some sparkling addition, to obtain nice sparkling trace.
Is it true the direct adding to candy any sparklers doesn't work?

Alex, Chernigiv,01.04.2004 20:12:59 :

Is it true the direct adding to candy any sparklers doesn't work?

 

The addition of titanium powder (coarse is better) apparently works very well with sugar propellants such as KNSB. I've seen some impressive photos of rockets being flown with such formulation. See
http://www.trailertrashaerospace.com/.../2-29-2004_chubsy_sparks1.jpg [not image]