Thursday, October 29, 2009

Last Post before contest...

I'm waiting for the last batch of Cat screens to heat up in the toaster oven before dipping in the secret sauce. So I have a few minutes. The rest of the day is going to be crazy so I won't post again until after the contest.

Nominally this is a two person team, Myself and My son, but in reality there is a large array of people that help out.

First and foremost is my wife Mariellen, without her support and assistance in a million ways both big and small this would not be possible.

My son. Without his help and countless hours this would not be possible. It has been a real joy to spend three years working with my son on a big project.

Bob our Welder. In the past week he has put in as many hours as we have. Without his assistance we could not possibly have been ready.

Charles Pooley of Microlaunchers. Charles has spent countless days and nights out at FAR helping us test.

Carl Tedesco of Flometrics. Carl has been a help both here iin San Diego and out at the FAR site.
He has offered help with both technical, fabrication and just being there to lend a hand.

Steve Harrington of Flometrics if you need to solve a fulids, flow, valving, heat transfer, or aerodynamics problem Steve is the goto guy. His assitance with figuring out the flow and flluid " science part of the rockets has been invaluable. So if you need anyhting done in this area give Steve a call.

Kevin Baxter. President of the FAR organization. Keven has been the driving force in creating a world class rocket test facility from scratch at FAR.

Mark and Ted of FAR. The other two principals in FAR have been invaluable in their help and assistance.

Michael Carden of XL Space systems. He has been my propellant supplier and peroxide guru for all things related.

Tom and all the guys at NetBurner that have been understanding of the CTO vanishing for every increasing amounts of time.

John Carmack and all the guys at Armadillo for being open, kind and helpful to a competitor.

All the guys at Masten, they have all been supportive and helpful.

Wynn Aung and all the people at the FAA that have been helpful and professional throughout the whole process.

Will ,Nicole Bill, and all the Xprize people that have organized the event for 4 years.

All the neighbors who think I'm crazy, but are still supportive anyway.

All the readers of this blog that have offer encouragement and kind words.

Wednesday, October 28, 2009

Good news...

I went to bed certain that our 180 second vehicle was dead. We split the tank over 20 inches of the main seam. My son and our welder Bob would not give up they got up at 6 am and spent the day grinding bending and otherwise beating the tank back into shape. They then re-welded the bad seam. At 2:30pm this afternoon it passed Hydro. Its clear that we are real close with little margin, but we do not pressurize in the presence of humans so even if it failed we would not hurt anyone. This was a 12 hr detour that we did not need. Its still a Hail Mary to be ready for the 180, but we are not yet dead.

As a result we are probably not going to be ready Friday Morning, its more likely we will try a Friday Afternoon flight and one or more Saturday Flights. I'm a bit hesitant to post the FAR map as we have had some theft problems, but I am going to post it for the next 24 hours.

If you want to come watch the earliest possible start is a Friday Noon safety briefing.
The Saturday Safety briefing will be at 7 am Saturday Morning. If you want to Camp at FAR you can. If yotu are not Xprize or Judges you will need to sign a FAR liabiliy waiver. You must be at the briefing to attend the event. It is very possible that Friday will be canceled entirely.

Far is a good 45 minutes from Mojave, and the road is rough. You may find the map here.

The ball is dropped in the end zone.

The tank failure we had last night is not recoverable in three days. We are not going to fly the 180 second L2 silver ball this year. If Masten continues their recent rapid progress and finishes the L2 180 second flights we will probably never fly the silver ball again. Its basically scrap metal.

At a personal level I've worked on this project for 3 years and spent enough $ to buy a nice house anywhere but CA. . We came oh so very close to fielding two vehicles, a tiny bit less corrosion in a weld and we would have two vehicles ready to fly.(Proof the Silver flew) As a team of two we built and flew two complete vehicles, but the odds are now that we will walk away with nothing to show for our efforts. Its a really really bitter pill.

I'm now going to get a long stream of comments saying you were two guys in a garage up against teams with multimillion dollar budgets. This is true, but there is no junior varsity contest, just the one contest. I started this to compete and hopefully win, its not to be.

My current task is to scrape myself off the floor and try to get the Blue Ball ready to fly. We have a legitimate shot of tying Masten for the L1 2nd prize.

Tuesday, October 27, 2009

Progress ,...

We ground off all the mounting tabs we were not using.
We welded the Safety Vent to the vehicle instead of using a heavy Stainless sanitary clamp.
We shortened the legs etc.... So we need to re-hydro the main tank. We got a pin hole leak where we ground off unused tabs. Argh!!! Weld a plate over and try again.. We needed to get to 425 PSI. The Tank Failed at 350 on the main seam. . We had hydro-ed it to 400 in the spring, so over the last 6 months it lost 50 PSI. Probably means we are done for the 180.

We patched the tank on the blue ball after a hydro failure, we will look at patching this tank in the AM, but 95% sure it means no 180 for us.

Monday, October 26, 2009


I have a theory as to why the cat pack suddenly died. (80% confidence) and I know how to avoid the issue. It was not my cost saving short cut. The old cat pack is being nitric acid stripped and re-plated. I've got all the material for a new no shortcuts CAT pack arriving at 8am Tuesday, with the Waterjet and Plateing house lined up to get a new one made. This should be ready Wednesday Afternoon.

We spent the day removing 40 lbs form the silver ball (Stainless fuel tanks and plumbing and misc unused fittings and bits. We then added back back 20lbs including a New higher capacity composite fuel tank and pressure bottles for external pressurization. The whole vehicle should be back together late Tuesday or Early Wednesday. It could hold double the propellant and it weighs 20 lbs less. The takeoff limitation will now be engine thrust, not propellant capacity.

If I can duplicate my in flight measured ratio of theoretical to actual performance I'll have 200 seconds of hover.

The LLC judges inspected our lunar pad and it passed.

Someone asked me today when I last had 8 hrs of sleep I asked if they meant in a single week?

Going to sleep UPS promises to arrive before 8 am.

Sunday, October 25, 2009

6 Days

Our 90 Second Vehicle is Ready.
Our RTK GPS tests with the helicopter say we have a chance to tie Masten in the 90 sec contest, but beating them outright would require some significant luck.

Our 180 Second vehicle is going to go down to the last minute. I disassembled the Motor and it looks good inside, the screens just look like they all got too hot. I think I need to change my warmup purge sequence. The sad part is that I really don't need to do a Cat pack warmup for normal ops, only for Tether ops as I need finer control of the in initial altitude on tether.

The vehicle flies at least as well as the blue ball, but we need to add a pressurization tank and
make weight reduction modifications to have any margin at all on the 180 second flight. Motor pressure drops are high so we need to hydro to a higher pressure and if the tank fails there we are done. I have parts of a spare Catalyst, but I took a cost reduction short cut on the last batch and they did not last as long as the previous batch. So I need to next day air some screen material and beg the waterjet and plating house to perform a miracle. It is all going to come down to the wire.

As one of the recent Masten posts commented about recent progress "we have had multiple consecutive miracles. " We will need similar to do 180. If we can fly for 180 seconds we can beat Armadillos accuracy, so it becomes a risk reward game.... IE On Saturday morning if we have a vehicle that would cost 50K to reproduce that has a 10% chance of success and a 90 % chance of destruction do we make the attempt? (0.9 * -$50K) vs (0.1 *$1M ) The calculus changes a little bit depending on Masten's result.

Are recently discussed on Twitter, Bon Nova is not going to fly this year.
I know exactly where they are in the process and its a really hard place to be in .
so close, but no realistic chance of completion, we were there last year.

Tuesday, October 20, 2009

Plans Update

We are going to go out to the site On Wedensday Morning set up and work on non-rocket flight things. RTK GPS base, Helicopter testing etc....(Can't fly the rocket on Wedensday, I forgot to Fax my FAA notification)
We will be flight testing Thursday and Friday and I think I have help for those days.
Its really hard to plan more than a day or two in advance but its really likely that I'll need some help during the week next week. So if you were so inclined check in on the blog or unrocket on twitter.

The current flight plans are to attempt the 90 second flight Friday Morning the 30th and the 180 second flight Saturday the 31st. If you want to come out and watch you will need to attend the safety briefing TBD some time late next week in Mojave. You will also need to sign the FAR liability waiver, I'll bring copies to the safety briefing.

The FAR site is about 45 minutes from Mojave out route 14. I'll provide a detailed map at the safety briefing.

The trip includes 10 miles of somewhat rough dirt road. (My wife drives her Honda civic out the road so its not too terrible.) Its actually really fun in my STI.

If you want to attend both days and can be 100% self sufficent you can probably camp on site Thursday Night and Friday. We will be camping on site and we will need our sleep so I'd really appreciate no 3am arrivals.

You can find my E-mail address phonetically in the comments of the previous blog thread.

Sunday, October 18, 2009

A quick update...

Currently in the passenger seat of the car on the way home.
Just spent 4 days at FAR camping. Worked on three things...

1)Navigating Pad to Pad flying the exact desired LLC profile with the helicopter, and new GPS system. This work went very well, many exactly repeatable flights, only one scare the GPS needs more voltage for proper operation than all the other electronics, so one flight the system battery was low and even tired, sun burnt and sleep deprived at dusk I mangaged to save the helicopter by taking over.

2)We had a very poorly timed large project for a customer. It was the largest rocket ever fired at FAR and the test went really well. Can't really say more.

3)We tyried to hover the silver ball. We got the altitude stuff under controll, but never managed a stable hover. Nothing we did in the way of loop tuning seemd to help. Got up before sunrise this morning to carefully look at everything in the system. I did some sweeps of the gimbal actuators trying to precisely measure dead band and hystersis. Came up with a sequience where the actuator moved OPPOSITE of the commanded direction. This jives with observations and as we would hover then just all of a sudden flip over to the abort limit. Seems to come and go depending on how I press on the PCB, I had no replacement with me so it means going home.

My son is in the middle of starting a new business and has other commitments for most of this week. I've got business commitments Monday and Tuesday, but I hope to go out to the site
Tuesday night for more testing. We will be short handed so if you are in the So cal area and don't mind hard work in the sun at a site with no good shelter and no running water we could really use some help.

Monday, October 12, 2009

Definition of Insanity....

Definition of insanity: Doing the same thing over and over and expecting different results.

Clearly we don't think we are doping the same thing, but the results are really similar....

Drive 4 hours, camp, setup test, fly abort, break the vehicle, driver home 4 hours, fix vehicle, lather rinse repeat.

We should have the vehicle back together tonight. We have fabricated a new version of the the part in the gimbal mount we broke, but we still need to fabricate a brace so it won't break again.

We failed to record data on the last flight, so almost no useful information from the test.
(The error was a tired operator error, not a fundamental problem)
I've spent the morning changing software so data will be recorded automagically without any operator intervention, in 3 places, on the ground station PC, on the telemetry box, on an SD card in the vehicle, just to be redundant.

Looking at what data I do have, several things are clear.... proportionally it looks like the gimbal system needs a lot more differential correction than the vanes did.

The system seems to be a lot more sensitive to every thing being level to start with, the vane system just plain ignores tilts of up to 15 degrees, does not even cause a noticeable start up transient. This gimbal vehicle seems to want to start out with a large transient.

On a spherical vehicle its actually really hard to be sure that everything is lined up level.
The IMU is level, the motor is dead level vertically, but I'm sure I have a center of mass offset for the partially full fuel tank. Again the vanes vehicle just ignored the center of mass offset when flying with the permanganate tank.

I'm not a big believer in software only simulations, I like to build real world analogs and test those, this may change my mind. For a long time my todo list has had a hardware in the loop simulator on the list, ie simulate IMU and GPS inputs to the computer, measure the actual valve and motor positions and use these to run the simulation. This will probably be my winter project.

Thursday, October 08, 2009

Off by a factor of 57.295779513.....

I've been playing with the high accuracy RTK GPS on the helicopter.
The software reports stunningly consistent positions etc....
But visually the helicopter wanders all over the world.

I've jsut solved it.
The Old GPS reports position in degrees, new GPS reports position in Radians!
Arghhhhh! Since I never actually looked at the lat lon positions I just told the vehicle to remember where "here" is and report distances from that reference point I never noticed.

I like using the binary records from the GPS's as parsing NEMA style text is a conversion that is not needed. If the binary record reports IEEE double format just use them. Alas The two GPS have different byte orders as well one is big endian one little endian, one reports velocity as heading and speed, one reports as vnorth and veast. I got all of these conversions working, but missed the radians/degrees difference. I'm tired and in a hurry, not the best situation for quality software. If NASA can make these kind of errors I guess I'm in good company. (Remember Mars Climate Orbiter?)

Wednesday, October 07, 2009


I've been working on the Vertical issue, so I have not really gotten to work on the position hold and overall horizontal stability. In viewing the Masten Video Several things are clear,

1)Their motor movement is a lot smaller than mine, I think I probably have the gross actuator gain turned up too far.

2)Its real clear that they switch modes on the descent, IE the vehicle it goes into tight position hold mode, the engine then starts moving a lot more.

In any case its cool to watch the videos.

Congradulations to Masten.

Congratulations to Masten. They did as good a job as is likely possible.

Their preliminary average landing accuracy was 15cm so based on my understanding of the rules we would have to have an average accuracy of 4.9 cm to beat them The vehicle reference point can move 5 cm just depending on how it settles on the gear. That is impressive.

To Tie and split the purse
we would need an accuracy of 25.9 cm or better.

On Monday I stopped by their shop and got a look at their L2 vehicle (I think I can now say this publicly as they have now published a picture of it) it's very light and looks largely complete. They probably just have to bolt the engine and electronics from xombie on it and they have a real good shot at Level 2.

All in all a very discouraging week.

Tuesday, October 06, 2009

Monday, October 05, 2009

Testing 1..2.. smack

We flew twice today. We smacked the forklift again, we are climbing too high , its now jumping off the ground going to the proper altitude sitting there for awhile then slowly ever so slowly climbing up up and away. I need to spend some time reviewing data and trying to understand whats going on.

On the last abort we smacked the forklift and tore off a landing gear.
We were really hoping to get some in flight performance measurements.
No such luck. About all we know is that its performance is better than the blue ball.
Is it enough better to do 180 seconds? That's the $1M question.

We will probably go out again Wednesday night or Thursday morning.

We were testing some new wide angle video and while the picture is not perfect (Its facing the sun) we got some really spectacular smack the forklift video. (The HD stuff takes to long to process on the computer I just don't have time.) This post was written in the car so the MiFi is working while enroute, and the laptop just does not have the cajones to edit video.

I'm really looking forward to Nov 1st.

Saturday, October 03, 2009

Testing again...

All tested and ready to go. Were on the way to FAR once more.

In reviewing the video of the last flight I was not really happy with it,
it was stable, but did wallow around more than I'd like. So I did a through review of the code and the adjustable variable settings. I found an error in my integral position gain. In my loop code I'd transitioned from having the displayed integral constant be the proper value or a percent value.
I'd set the value like a percent and used it as a normal so the itnegral gain was 100x too high.
This makes me much happier as the flight visually looked like an earlier blue ball flight that had the same problem. The code set started on the helicopter and transitioned to the blue ball and from there to the silver. I've tried to put all the vehicle specific stuff in a separate compilation modules, but the code has now drifted so I have three similar but not identical code sets.

I Started out with everything under CVS on my main computer with updates from the laptop. Then the laptop died and code was moved to the backup laptop in the field and the CVS stuff has not caught up. The project always has the dilemma, stop and fix a systematic problem where it effects your productivity, but not the actual flight vehicle. 6 months ago these decisions were easier, now it's will the time taken to fix "This" have a payback in the next 27 days.

I'ts pretty clear that the "2nd" gneration is better than the first. The Blue ball is our 2nd gen vehicle, the silver is gen 2.5. We have lots of things we know we would do different on gen 3, yet the current plans for gen 3 add the whole aerodynamics aspect that is missing from the LLC vehicles.

Thursday, October 01, 2009

Driving home again...

We tried one hover test this morning about 11:45 am. The vehicle was stable, but we continue to have vertical throttle control issues, as it climbed above the fork lift then aborted when the ropes jerked on it hard enough to exceed the tether tilt abort limits. This happened simultaneously with my hitting abort. Luckily we missed the forklift and did no physical damage. The pressure readings were being erratic all morning and after the flight we did some debugging and one of the transducers shorted, taking out the A/D converter and letting out the electronic magic smoke. Putting short protection on the 4-20 ma transducers has been on my "I really should do that some time list". I guess it will be friday. So if all goes well we will be doing the 4 hour drive again on Friday night.

After determining that the vehicle was not fixable in the desert, we also received a delivery of propellant and decanted that from drums to smaller poly totes. Right before sunset we flew the helicoipter with the full RTK gps stuff running. Much more accurate, Seems to be more stable, but we ran out of light so we will test that more this weekend.

Its 9:30 PM we are 2:45 min from home (my son is driving), I'm on the web with the new MiFi wireless access point. It does not work at the FAR site, but works on the road to and from. In the past its always been that both my son and I wanted to drive as being passenger was really boring,with live internet access now the other eway around as the passenger can surf,,,, I think I'm going to go read the Firday XKCD.