Thursday, March 17, 2011

Past...Present..Future...Plans (updated)

On March 5th we watched Garvey space have a perfect flight.
We tested a commercial GPS and out stainless printed motor.

The Motor had cat pack issues,
The peroxide has to flow through the cat pack and not around it.
This is done by adding rings that look like piston rings and expand out against the barrel of the cat pack area and block flow that wants to go around the outside. I disassembled the pack tonight and I had 4 anti channeling rings in the pack. The top ring was fine, the second ring was a bit distorted, the 3rd was badly burnt and thinned and the last one came out in tiny bits. I'm going to try stainless C clips as anti channeling baffles and we will see how that goes.

The GPS stopped updating the moment the motor lit.

I'm going to use some tougher stainless snap rings as anti channeling baffles.

Today I received my 2nd version of a GPS front end board and hopefully will get to try it this weekend. (rakon grm8652 integrated GPS front end )

The Max2769 eval board is due in on Friday if UPS is to be believed.

This Saturday we will try firing the small stainless printed motor with modified anti channeling baffles in the cat pack.

Some time in April we might get our first test tank under the Tank development process with we are doing jointly with microcosm.

I have high hopes to have a high dynamics GPS to actually fly by the next FAR outing the first Saturday in April.

My current Plan of record:

1)Work on the small 3D printed motors both stainless and aluminum until I have a viable 3rd stage motor.

2)In parallel work on high dynamics GPS and IMU integration using HPR rockets to test,

3)Tank development continues. (my involvement with this is limited until testing is needed)

4)When I have the high dynamic gps/imu working add some small canard control fins to the
HPR test rocket and see if we can control the trajectory.
This may possibly be done with vanes in the exhaust instead of canard fins.

5)Combine steps 1-4 to see if we can fly a small rocket to 100Km.


Thom Vincent said...

Hi Paul,

I recently tuned in to your blog and am enjoying reading through your adventures, from the beginning. This is great stuff.

Also, as an FYI, a couple days ago I did post a comment on your "An open message for Blue Origin" post - twice - but neither one have shown up. Perhaps someone needs to approve them, so they will show up? I'm not sure.

Keep up the good work!


Paul Breed said...

I follow a financial blog that is blogger based and there have been lots of complaints about posts vanishing recently. I don't have moderation turned on so I don't know why the BO posts aren't appearing.

Glad you are enjoying the blog.

Anonymous said...

What's the financial blog that you follow? (Seriously)

Paul Breed said...

Some of the financial news/blogs I follow are
Good accurate data, a real good news source.

A bit weird, but some real gems in the comments.
Is also good, but his very last post less so than some of his earlier work.

All of these blogs are a bit doom and gloom and I fear that they might be correct. The current U.S. governemnt has a deficit of > 1600+ Billion and can't seem to agree to cut 6B. For 30 years the U.S. has been sending the rest of the world IOU's and getting "realstuff" in return. This can not continue forever.
If this does not scare you you aren't paying attention.

I've contemplated making a blog post about what I see on the horizon in the world but have chosen not to.

Comments on if this would be appropriate are welcome.

Thom Vincent said...


Here are some ideas you may want to try, if you haven't tried them already ...

1) Wrap your anti channeling rings in ablative material - or, put a 'protective washer' of ablative material above and below each ring - to protect them from the heat.

2) Test your anti channeling rings by themselves to see if their material is reacting with the peroxide directly.

3) Replace the 'piston rings' with 'spacer' rings/tubes. Do this by increasing the diameter of your catalyst pack chamber and catalyst screens - while keeping the diameter of the chambers above it and below it the same. Sit a spacer ring/tube on the chamber wall below, add the lowest layer of catalyst screens, add another spacer ring/tube, etc. Hold it all in place with compression on the spacer rings/tubes exerted by the walls of the chamber below and the chamber above. Make the spacer rings/tubes out of whatever material can handle the heat and the compression/expansion forces.

4) Set aside the anti channeling rings and - instead - wrap the outside diameter of your catalyst pack(s) with ablative material, until there is a tight fit between the pack and the catalyst chamber.

5) Some combination of the above.



PS - I finally got my comment to show up on your "Blue Origin" post from January. ~T

heroineworshipper said...

For simple QFN's like the MAX2769, you should spin your own boards instead of waiting months for BatchPCB. Whenever we need a board, we make one in an hour with the laser printer, draino, & FeCl.

Thom Vincent said...


6) Set aside the anti channeling rings, keep the chambers the same diameter, and make your catalyst screens a slightly larger diameter than the inside diameter of your catalyst chamber. When the screens are inserted/tamped into place in the chamber, their outside edges curve up slightly, eliminating the need for anti channeling baffles (in theory, at least).

{ By referring to 'catalyst screens', I am assuming your peroxide engine is similar in design to those produced by TAM. I have not read enough of your back posts yet to know if that is correct or not, however. }


Paul Breed said...

Thom in your BO post you asked about discussion groups...

The best is probably:

Where are you located in New England?
New Hampshire is on my short list of places I want to leave CA for. I lived in NH for ten years from 1991 to 2001 and I miss the place.

The lack of someplace to launch rockets there is one of the big drawbacks. (Shoveling snow comes in a close 2nd)

Anonymous said...

RE: NH.. The density of Democrats in the general region is another.

Good luck with testing this weekend.

Paul Breed said...

NH is currently a tug a war between the MA dems and the free state project libertarians.

One reason to go to NH is to support the free state guys...

Anonymous said...

Paul, I enjoyed the few days I helped in the desert leading up to the LLXP attempt. I know you have a lot invested in the HTP engine concept, but aren't these catpacks just a royal pain in the ass? As you know I don't know jack about this stuff, I just know what a pain it was to work with, just by observation, seemed like lots of marginality of chemistry, uncertain suppliers, etc.

Anonymous said...

How about some strap on HPR boosters and a peroxide sustainer. That should get you to 100Km. Just hold it down until all three are at 90%.

As far as libertarianism, it just doesn't work in the real world. All these government organizations that you think could be defunded actually prevent some bad shit that hasn't happened in many years, because the organizations exist. When's the last time a union killed someone for hiring a non-union shop? When is the last time some desperate criminal kidnapped a wealthy person's child? What would happen in LA if no-one checked the cars for smog? ( I lived there in the early 70's when the air was so bad you could not go outside) What would happen to Netburner, if the justice dept did not follow up on copyright violations? All this stuff that we take for granted cannot just be destroyed willy nilly. Cutting budgets is hard, brutal work. Every time you propose to cut, the people who are about to lose their funding will scream and fuss, so you need to argue and fight to get their program eliminated and transfer the critical functions to another organization. If you just defund an organization and never change the rules that they are supposed to enforce, you end up destroying the rule of law. Right now we are torturing Bradley Manning, who has not been convicted. We are also keeping various people at Gitmo without trying them. Both of these activities are absolutely against the law, and our president is fully aware of this, as he used to be a law professor. However, it sounds good on TV to punish people who look like bad guys, so the government is allowed to continue its criminal activity.

C. Scott Ananian said...

heroineworshipper: don't use batchPCB for anything you care about receiving quickly. and don't try to hand-etch PCBs either! Just sent it to (or any one of a number of similar services) and get boards next day for ~$50. It's so cheap, there's no reason to do it any other way, unless you really care about reducing costs and don't care about lead time. There are some applications in this latter category; I've used batchpcb for stuff, too. But I'll never try to hand-etch (or CNC route) boards again. Some things really are best left to the professionals.

Re: the deficit -- I'm no economist, but you should be careful about falling into the trap of thinking that a government's bank balances must balance like your personal checkbook. When you're discussing global-scale numbers on paper, you have to keep in mind that you've left the realm where analogies to everyday financial transactions apply.

Thom Vincent said...


Thanks for the tip on aRocket. I had heard of it, but had not joined the list until now. I checked the Archives and it only lists emails back to July 2010. I thought aRocket had been around longer than that?

As for where I live .. I'm currently in south central Connecticut. Just moved here a few months back from the Mid-Atlantic area. I haven't had a chance to drive around New England and see the other states yet, but hope to get a chance when the weather gets warmer.

Good to see your GPS project coming along.


Paul Breed said...

arocket moved to a new sever in 2010.
Dave, the guy who runs it has not gotten around to moving the archives over.


Martijn Meijering said...

(repost, previous try disappeared)


Are you familiar with the work Aerojet did on platelet-based hydrogen peroxide catalyst packs? It promises to avoid problems with channelling and lack of reproducibility. You might be able to do something similar with 3d printing instead of platelets to avoid running into Aerojet patents.

Monolithic Hydrogen Peroxide Catalyst Bed Development

With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

Brian H said...

Stein's Law: If something cannot go on forever, it will stop.

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RE: NH.. The density of Democrats in the general region is another.

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