Video Caption: On March 3rd, the Rice Eclipse team conducted two hot fires of the Luna hybrid rocket engine. The first test, the seventh of this propulsion system, implemented gas injection thrust vector control and a new impinging injector plate geometry. The second test used a recently machined combustion chamber and bulkhead as well as a new batch of chemicals. If you would like to learn more about our team and projects, please visit our website at http://eclipse.rice.edu/ or contact us at firstname.lastname@example.org.
Joe from BPS continues on his quest to propulsively land a model rocket, as seen in his latest test, Joe is well on his way to making it happen. You can buy the exact same Signal flight computer and try it yourself!
Video Caption: This is the first real test of model rocket retro-propulsion! At 50m AGL, Signal(the flight computer) commanded release and began computing the optimal retro-burn altitude to “land” the rocket at 14m AGL. Signal missed its landing target by a whopping factor of 2, landing instead at 30m AGL. There are several factors involved, but the most likely candidate is that the pre-flight simulations used to generate the landing math were out of date. Now with real flight data, we can dial in landing simulations more reliably. As with SpaceX and Blue Origin, getting this well-tuned will take several tries.
Stability was quite poor during this test, I believe this was caused by excessive roll on the vehicle. At this time, the current theory for roll accumulation is abnormal motor nozzle geometry. Post-flight motor inspection confirms this as well, and the flight data shows a steady increase in Z axis roll as the burn progresses. This is generally rare, and I’ve only noticed it occasionally with these motors. Aerodynamic sources seem unlikely as roll continues to accumulate at low airspeeds. The TVC servos have been characterized to handle roughly 180 degrees per second of roll before they can no longer keep up, and this holds true in the flight data as well. More tests like this will certainly be performed, but before that we need to review a lot of data!
Joe Barnard of BPS.space has flown his 1/48 scale Falcon Heavy model demonstrating the ability of the Signal flight computer to control a 3 core rocket. Each core was equipped with its own Signal FC and TVC (Thrust Vector Control) mount, by firing the two core boosters at liftoff the combined TVC control allows the rocket to pitch, yaw and roll about its axis.
As is demonstrated in the video below, the rocket executes a 20° roll program after liftoff and holds this until burn out before the centre core takes over and flys away.
The model even has a second stage fully equipped as well, lets hope we see an all up test soon!
A pretty awesome feat!
I’ll let the video do the rest of the talking!
BPS recently tested out a new experimental rocket motor from Aerotech, a G8ST. Producing an average thrust of 8.3N for 17.7s, this was the perfect motor for testing the in-house designed and built Signal avionics TVC package.
Revision 2 of the avionics is now available to buy, so if you are wanting to take your rocketry to the next level, you’ll need this package to guide you!
A quick note: While the motor did melt the PLA tube holding it, the rest of the TVC assembly(outer/inner gimbal, servos, linkages) were unaffected. Since the heat of the motor was so intense, it’s unlikely we’ll be able to mitigate it using more liners than were already there. The same goes for using most other plastic FDM materials. For now, we’ll probably cut the burn time down a bit and make sure users have access to extra motor mount tubes, should one of them melt. The motor tubes are incredibly easy to manufacture and replace, and the priority right now is ensuring Signal’s software and UX are top notch.
Joe Barnard of BPS has just released his Signal Avionics flight computer and it is full of cool features that any amateur rocketeer has been waiting to see!
This is no normal flight computer, Signal Alpha is a full thrust vectoring kit which essentially enables you to fly your rockets with gimbaled engines and no fins! Imagine the possibilities now open to you for experimentation in your park.
Joe does a much better job explaining all the features in the video below but for USD$299 you cannot go wrong for what this little board can do.
I look forward to it being ITAR friendly so I can get my hands on this gem!