54mm M motor?

[Binder Design]

Will it be lit from below at the boundary?

Yes, the igniter will only be inserted until it hits the upper grains. No way it could possibly fit up the small cores of the top grains.

 

[Binder Design]

You guys need to check out the sugar shot to space website. They are using this conops with big sugar motors. Very difficult.

Yes, that is why I chose another easier route. I could see too many failure modes that might take years to resolve.

 

[g zilla]

could you light the top half with thermalite.

 

[bobkrech]

Ive had an idea for a motor for long time now. I had spoke with Gary and Frank about it about 10 years ago.Frank said he played around with the idea before but never really worked out. Maybe someone else can. I call it a 2 stage motor we willcall it 54mm 72" long not specific.Use 30" of propellant with normal burn 1 slug of solid propellant about 3" and another30" section of regular propellant. Motor burns for about 1 second followed by 4-6 seconds of low thrust end burn slug burns through lights top section another 1-2 seconds of burn. Has anyone tried this before would take a lot of calculating to figure out but I think it is possible.

A variable thrust versus time profile is used in some air to air missiles and other tactical missiles. The SRBs used also use a variable thrust versus time profile. This is attained by using complicated core mandrels during the casting of the propellant.

The instantaneous thrust of a solid motor is proportional to the burning area of the propellant grain as a function of time multiplied by the chamber pressure raised to some power slightly greater than 1. For tactical applications you want a missile to accelerate quickly to a cruise speed, stay at cruise speed for a certain time and then accelerate to the end game. The shuttle SRBs throttled back for about 15-20 seconds as the vehicle approached and passed max Q to minimize the dynamic loads on the shuttle and external tank. The mandrels required to form the initial core shape are not simple cylinders and a fair bit of engineering is required to make them removable after the grain is case. In some missiles the mandrel is made from plastic foam and is left in place and is consumed upon motor ignition.

Sugar Shot to Space tried something like that, I think.

For AP motors you would need a really really good liner I suspect.

Sugar Shot uses a dual pulse single stage motor. The motor casing is divided into 2 equal sized chambers separated by a burstable diaphragm. At lift-off, the first chamber is ignited and burns for ~ 9 seconds, from lift-off and to about Mach 1.5 and a few miles altitude. The rocket then coasts fro ~10 seconds to about 5 miles gradually loosing velocity to ~ Mach 1 when the second chamber is ignited. In the following 9 seconds, the rocket accelerates from ~Mach 1 to > Mach 5 at about 8 miles and then will coast up to more than 60 miles.

The reason for the unconventional thrust profile is that sugar propellant is only half as efficient as APCP: Isp = 130 s versus 260 s. If all the propellant was consumed in one burn, much of the energy would be expended in overcoming the drag forces at higher Mach number in the lower atmosphere. (Drag is proportional to Mach No. squared and the power required to maintain velocity is proportional to Mach No. cube. By shutting the engine off in the lower atmosphere and coasting, no propellant is wasted to fight drag. At 25,000' most of the atmosphere is below you so the majority of the thrust goes into acceleration of the rocket versus overcoming atmospheric drag.

The greatest problem facing Sugar Shot, Arcas and all long burn end burners is thermal damage to the motor casing when the surface is not longer protected by propellant. The aft end of the Arcas had to withstand ~40 seconds of hot combustion gas impingement which is about as severe as it gets. Only a few unclassified methods are available to the hobby rocket community and all have one or more issues.

Bob

 

[Binder Design]

could you light the top half with thermalite.

Sure, you could put a long length of that in the top section, then you would not need head end electronics to start the second burn. You'd still have the liner issues, as well as the problems that SSTS is dealing with namely the cato @ start of second ignition caused by all the "crap" left in the motor after the first phase burn. It is clogging the nozzle.

Not sure why they are not just doing a traditional two stage because they would be able to dump some weight and drag after the booster burned out. Less drag during coast phase, less weight to boost during sustainer burn. Their current plan is elegant if they can overcome all of the problems that crop up. Ground breaking for sure, but they are in it for the long haul it seems.

 

[CarVac]

Sure, you could put a long length of that in the top section, then you would not need head end electronics to start the second burn. You'd still have the liner issues, as well as the problems that SSTS is dealing with namely the cato @ start of second ignition caused by all the "crap" left in the motor after the first phase burn. It is clogging the nozzle.

Not sure why they are not just doing a traditional two stage because they would be able to dump some weight and drag after the booster burned out. Less drag during coast phase, less weight to boost during sustainer burn. Their current plan is elegant if they can overcome all of the problems that crop up. Ground breaking for sure, but they are in it for the long haul it seems.

The reason they aren't doing staging is because they don't think they can keep the dispersion small enough to stay in Black Rock when stated.

 

[boomtube]

Does anybody make a 54mm “L” motor?

 

[CarVac]

Does anybody make a 54mm “L” motor?

Many do. AT makes the KBA L2300 and DMS L1000, CTI has a selection for the 6gxl case, and Loki has the L1400 and various in-development ones which will be fuller L's. I am not sure about AMW or Gorilla, though.

 

[A5tr0 An0n]

Does anybody make a 54mm “L” motor?

Many do. AT makes the KBA L2300 and DMS L1000, CTI has a selection for the 6gxl case, and Loki has the L1400 and various in-development ones which will be fuller L's. I am not sure about AMW or Gorilla, though.

To add on, AMW does have two I think for their 54-2550 cases. The L985 and L1276 are their 2 motors. I do not know about Gorilla.

 

[4kids49]

To add on, AMW does have two I think for their 54-2550 cases. The L985 and L1276 are their 2 motors. I do not know about Gorilla.

Yes, and the reloads are CTI for AMW. They are CTI mixes (L985 is Classic) and L1276 is Red Lightning and very similar to the CTI L1030. I have CTI and the AMW 2550. The AMW 2550 case is longer than the CTI 6XL and seemingly heavier. The reloads are cheap, some have a smoke grain. It would be great if CTI could make a bigger total Ns motor for the 2550, maybe dumping the smoke grain. The CTI L935 IMax is awesome. But since the AMW 2550 is longer, it would be great to max it out. Just my 2 cents. I am a big fan of CTI. Would just like to cram as much into a 54 mm as possible. Loki 54/4000 motor is awesome, but can't buy loads in California.

 

[ksaves2]

Loki L1400 in my stretched 3" Wildman was good for nearly 10k and Mach 1.

 

[bobkrech]

Sure, you could put a long length of that in the top section, then you would not need head end electronics to start the second burn. You'd still have the liner issues, as well as the problems that SSTS is dealing with namely the cato @ start of second ignition caused by all the "crap" left in the motor after the first phase burn. It is clogging the nozzle.

Not sure why they are not just doing a traditional two stage because they would be able to dump some weight and drag after the booster burned out. Less drag during coast phase, less weight to boost during sustainer burn. Their current plan is elegant if they can overcome all of the problems that crop up. Ground breaking for sure, but they are in it for the long haul it seems.

The goal of SugarShot is to launch a sugar propellant powered rocket into space which is defined as over 100 km. This is very difficult to accomplish because the specific impulse of sugar propellant is only 130 seconds. Over 100 detailed flight simulations were performed in 2005-2006 to determine the optimum vehicle configuration and it was definitively shown that neither a single stage or a two stage rocket could reach 100 km on sugar propellant. (It has nothing to do with dispersion or uncertainty of the trajectory.) The gateway to 100 km+ is to reach Mach 5+ at 40 kft. The 10" diameter x 22' long single-stage GoFast rocket did this on APCP as have many other 10" diameter x ~>17' long single-stage military and commercial APCP rockets. A 10" diameter single-stage rocket on KnSb burns up much of its propellant fighting drag in the lower atmosphere and won't apogee anywhere close to 100 km. Similarity, a two-stage rocket can reach the required velocity at 40 kft, however as the minimum propellant fraction to reach 100 km on sugar propellant is 0.82, the sectional density of the second stage is too low to coast to 100 km due to insufficient retained momentum. The only way you can reach 100 km+ on sugar propellant is to use a dual impulse single stage motor using the flight profile I describe in my previous post. You need the momentum due to the total mass of the single stage rocket to get there and this is why the program is so difficult as the thermal load on the motor casing/airframe is severe during the second burn.

The calculations are all documented on the https://www.sugarshot.org website.

Bob

 

[Binder Design]

Similarity, a two-stage rocket can reach the required velocity at 40 kft, however as the minimum propellant fraction to reach 100 km on sugar propellant is 0.82, the sectional density of the second stage is too low to coast to 100 km due to insufficient retained momentum.
Bob

Makes sense to me now, thanks.

 

[High Desert Rocketry]

Ive had an idea for a motor for long time now. I had spoke with Gary and Frank about it about 10 years ago.Frank said he played around with the idea before but never really worked out. Maybe someone else can. I call it a 2 stage motor we willcall it 54mm 72" long not specific.Use 30" of propellant with normal burn 1 slug of solid propellant about 3" and another30" section of regular propellant. Motor burns for about 1 second followed by 4-6 seconds of low thrust end burn slug burns through lights top section another 1-2 seconds of burn. Has anyone tried this before would take a lot of calculating to figure out but I think it is possible.

Gary,

I built a 38mm motor like this a few years ago with KNSB and static fired it at one of Frank Kosdon's EX events at Lucerne. I actually cast this using several pours with paper blocks to separate the different sections. It experienced several problems, the longer aft motor ignited and burned nominally and the delay worked as planned but the forward motor auto-ignition failed to light properly and the remaining burn was erratic , akin to a 'chuffing' motor. On top of that were the thermal heating issues of the nozzle end. No further testing was done on that design. I have a video of that somewhere but you get the idea.

Rick

 

[High Desert Rocketry]

A 240 fps GoPro seems a little slow.

For those doing static motor testing that want to compliment the 'regular' speed video they take with something faster but are on a budget, I would like to suggest one of the Casio Exilim High Speed digital cameras. They have several models that can record at 210, 480, and 1,000 fps (the resolution goes down as the speed goes up). And if you are really on a budget sometimes you can pick one up on ebay for $100-200 after people get tired of taking golf swing or kids baseball swings...that's how I got the one I use for many of the Sugar Shot to Space videos.

[video=youtube;vXaRzSZEbOA]https://www.youtube.com/watch?v=vXaRzSZEbOA&list=UUgE9yxooDx1UwelAT7Xu7gQ[/video]

for several other examples, search mojaverockets on youtube

Rick

 

[High Desert Rocketry]

The only way you can reach 100 km+ on sugar propellant is to use a dual impulse single stage motor using the flight profile I describe in my previous post. You need the momentum due to the total mass of the single stage rocket to get there and this is why the program is so difficult as the thermal load on the motor casing/airframe is severe during the second burn.

Not being on the project the first two years, it is hard to find the original reason for the dual-pulse motor design. I have been told it was both dispersion area and momentum. Because of difficulties developing the dual-pulse motor for the Sugar Shot to Space project, we are shelving that approach for a conventional 2-stage rocket.

We have done sims that show the required 2-stage vehicle will be smaller overall than the single dual-pulse vehicle that was being tested with small scale versions (MiniSShot and DoubleSShot). Testing of the first motor for the '2-stage' MiniSShot size scale rocket will commence next weekend. This testing will consist of static firing the sustainer motor, flight testing the sustainer, static testing the booster motor, flight testing the booster motor and if all goes to plan, a combined 2-stage flight of the vehicle before the end of the year.

Rick

 

[JohnCoker]

Does anybody make a 54mm “L” motor?

The ThrustCurve.org motor browser has the answer.

 

[daveyfire]

Not being on the project the first two years, it is hard to find the original reason for the dual-pulse motor design. I have been told it was both dispersion area and momentum. Because of difficulties developing the dual-pulse motor for the Sugar Shot to Space project, we are shelving that approach for a conventional 2-stage rocket.

We have done sims that show the required 2-stage vehicle will be smaller overall than the single dual-pulse vehicle that was being tested with small scale versions (MiniSShot and DoubleSShot). Testing of the first motor for the '2-stage' MiniSShot size scale rocket will commence next weekend. This testing will consist of static firing the sustainer motor, flight testing the sustainer, static testing the booster motor, flight testing the booster motor and if all goes to plan, a combined 2-stage flight of the vehicle before the end of the year.

I take it the telecon went well then? :clap:

 

[High Desert Rocketry]

I feel it did, we are changing direction with the 2-stage instead of dual-pulse motor design...we shall see what results we get.

Rick

ps Always looking for new volunteers David ( :