[Progress] Minimum Diameter 54 (CTI L935)

[A5tr0 An0n]

Man I'm so jealous. The AIM XTRA 2.0 has got real slim. I really need to get it for my Mariah 54. By the way the AIM XTRA uses all the sensors to avoid the possibility of being fooled it has gone past apogee during super sonic transitions.

Nice e-bay set up.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

The AIM XTRA does have the Kalman filter and does utilize GPS deployment amongst other things. With that being said on this particular flight I set the AIM to ignore pressure data on the ascent. I am not sure if this is a requirement or not for the Kalman filter to be activated because in the programming box where you select to ignore, it is titled "Kalman Filter," so a bit confusing. I spoke with Gary and he said you did not have to set the board to ignore, but I chose to for added safety.

 

[CarVac]

The AIM XTRA does have the Kalman filter and does utilize GPS deployment amongst other things. With that being said on this particular flight I set the AIM to ignore pressure data on the ascent. I am not sure if this is a requirement or not for the Kalman filter to be activated because in the programming box where you select to ignore, it is titled "Kalman Filter," so a bit confusing. I spoke with Gary and he said you did not have to set the board to ignore, but I chose to for added safety.

Ignoring the pressure on ascent was a feature requested for Bare Necessities, which has a sealed avionics bay and so has zero pressure change until apogee. You definitely should not use that feature.

 

[A5tr0 An0n]

Ignoring the pressure on ascent was a feature requested for Bare Necessities, which has a sealed avionics bay and so has zero pressure change until apogee. You definitely should not use that feature.

Interesting to know that is where that feature originated from.

The AIM would then just use the acceleration and GPS data for the ascent. Plus I had a redundant computer and heard no negative comment from Gary when asked, so I think it is okay. By the way… it still detected apogee fine and fired the charge. Maybe I am overlooking something?

 

[REK]

It would most likely be a good idea to turn it off. The reason for that is again it uses all sensors so if it was using the baro and you have no air pressure port. Chances are it might think, this rocket isnt going nowhere lol.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

 

[CarVac]

Interesting to know that is where that feature originated from.

The AIM would then just use the acceleration and GPS data for the ascent. Plus I had a redundant computer and heard no negative comment from Gary when asked, so I think it is okay. By the way… it still detected apogee fine and fired the charge. Maybe I am overlooking something?

Basically it turns it into an accel-only (with GPS, but that's extremely slow reacting by comparison) altimeter, which will not do so well if the rocket weathercocks a lot.

 

[A5tr0 An0n]

I thought that the GPS data might be slow and/or not good, but wasn't sure. Good point on the weather coking. Would you happen to remember what the lag time roughly is?

 

[A5tr0 An0n]

The launch approach was to be launched via a tower. If more information is desired about the tower you can check the tower build thread here -> https://www.rocketryforum.com/showthread.php?67902-Versatility-Adjustable-Launch-Tower. I have attached some pictures of the vehicle out in the tower and ready for launch.

Nice clear skies.

Slightly close up.

Sacrificial camera. I did not bother repainting the rocket.

GoPro 3 afar.

Up top view of the camera. You can see here that it was professionally attached haha.


Will post more later today.

 

[4kids49]

All of the electronics are housed in the nose cone therefore and I need a bulkhead. Now this vehicle is designed for two purposes and the later will need just a little extra forward mass and a Aluminum bulkhead does just that. I chose 6061 T6 as the material and think it is an all around good choice for this application. The electronics sled will be bolted directly to the bulkhead and the bulkhead will be bolted to the shoulder.

CAD drawings. I had to shrink them down to fit it all onto one page and it has distorted the quality a bit.


There are a few changes from the CAD designs and the finished product, mainly to make it a little more structurally sound around the eyebolt connection.

Various sides and shots.

Assembly shot. Note the non forged eyebolt is for show only.

Assembly shot number two. Note the non forged eyebolt is for show only.

Final mass came in at 0.168lbs and the metrics are also pretty close and down the line to the CAD.

Mat

Nice bulkhead. How did you have it made? Is it an aluminum plate welded to a piece of tubing? The tubing being the part that inserts into the nosecone shoulder coupler?

 

[A5tr0 An0n]

Nice bulkhead. How did you have it made? Is it an aluminum plate welded to a piece of tubing? The tubing being the part that inserts into the nosecone shoulder coupler?

Thank you and no it is not a plate welded to a tube. It was made from Al. 6061 T6 bar stock with most of the work being done on a lathe.

 

[A5tr0 An0n]

Here are some pictures from the launch. I launched this at one of the fun flies in Argonia,KS. It flew on a CTI L935. I did make a video a while back that I will be posting soon with more data, however there are some edits that I need to make. Perhaps one of the cool things about this flight was that there was an airliner up at 35kft when we launched. Progress was expected to go around 28kft and the ATC had been notified and gave us the airspace needed, so it was safe irregardless of how it sounds :/. It was very interesting to see the comparison of altitude with an object at 35kft.

Ignition.

Cleared the tower.

Dirt, smoke, and a rocket coming out.

Away shot. Not to bad of a picture seeing as the rocket left in a hurry and this is a screen shot of the video.

Up close shot. Descent flame:rocket ratio.

Straight enough for me and starting to climb.

Meh.

Argonia land is ever so soft. Will make a simple mod to the tower to prevent this in the future.



Video coming soon.

Cheers.

 

[4kids49]

Thank you and no it is not a plate welded to a tube. It was made from Al. 6061 T6 bar stock with most of the work being done on a lathe.

Cool. Is that something that is relatively easy to do? Could I take my own simple design to a CNC place for a reasonable cost? Interesting design on the motor retention. It would be nice if you could add some motor length flexibility to be able to get the shorter K1440, K2045, and the slightly longer, L265 Mellow Yellow, as your rocket should perform well.

 

[A5tr0 An0n]

Cool. Is that something that is relatively easy to do? Could I take my own simple design to a CNC place for a reasonable cost? Interesting design on the motor retention. It would be nice if you could add some motor length flexibility to be able to get the shorter K1440, K2045, and the slightly longer, L265 Mellow Yellow, as your rocket should perform well.

I am not sure how easy it would be. First you need to have access to CAD software to design the item and then you could send that out and have it made I suppose. This was done manually and not via a CNC so a little different I would suspect that it is more cost effective to buy a mini lathe and learn how to use it vs paying to have it made. I could easily see the parts coming out to costing more than the machine after a couple go's where as mini lathes can start at $500 (decent ones for DIY use). Hope that helps.

Thank you for the kind words on the design of the motor retention.

As far as having flexibility for different motors, there is some. At first glance it might seem to fit only one length of motor however there is an easy modification that can be made to fit various motor lengths. I did something similar to here on my ODIN rocket. Check out the link in post #39 for a general description and photos. -->https://www.rocketryforum.com/showthread.php?66514-ODIN-Minimum-Diameter-38/page2 With that being said, I really only built this vehicle for two motor configurations and both of those mount in the same place.

 

[A5tr0 An0n]

I have been meaning to update this thread with the video I put together awhile back but it slipped my mind… so here it is. I was planning on updating the video but do not have time.

[video=youtube;8yw0w-L2CFM]https://www.youtube.com/watch?v=8yw0w-L2CFM&feature=youtu.be[/video]

 

[REK]

Nice flight Mat, good job on the rocket.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

 

[Handeman]

Great flight! Wish we could do those types of flight on the east coast.

How far from the pad was it recovered?

 

[A5tr0 An0n]

Thanks.

It was recovered about 1 mile from the launch point… give or take.

 

[dandreat]

Great build thread with lots of tips for an MD project. I especially like the analysis and details.

I'm struggling with some similar motor retention issues. I'm hoping to design, build, and place some form of forward retainer to accommodate a wide range of my existing 38/54mm CTI cases (w/ adapters, of course) AND, finally, an AT L1000. The hex-to-cylinder approach you used is clever. That eliminates the boss(es) extending forward and aft. The minimal recovery space is precious so I don't want to use up too much. The lengths of CTI 6 grain cases and the L1000 are just different enough, with their variety of potential forward retention adapters, that I have to carefully ponder the options.

Great project and documentation. Thank you for the inspiration!

 

[Dipstick]

Great build thread with lots of tips for an MD project. I especially like the analysis and details.

I'm struggling with some similar motor retention issues. I'm hoping to design, build, and place some form of forward retainer to accommodate a wide range of my existing 38/54mm CTI cases (w/ adapters, of course) AND, finally, an AT L1000. The hex-to-cylinder approach you used is clever. That eliminates the boss(es) extending forward and aft. The minimal recovery space is precious so I don't want to use up too much. The lengths of CTI 6 grain cases and the L1000 are just different enough, with their variety of potential forward retention adapters, that I have to carefully ponder the options.

Great project and documentation. Thank you for the inspiration!

I agree, nice thread and great results. I still like CJ's retention method. Friction fit the casing, then use a band of aluminum tape around the rear of the airframe and the motor closure. Works great.

 

[watheyak]

I recently flew an L935 in a similar MD rocket and used aluminum tape. After the flight, the tape was long gone. I guess it's not 2000mph tape

Your mileage may vary.