Wednesday, May 28, 2008

O to N two stage flight





This rocket
is one of the largest two stage amateur flights to date. Compare this to project tupelo, the two stage shadow aero kit (shock X2), and mostly to the project thunderbolt that used similar sized motors. Performance was huge, above mach 3 (something that the shadow aero web page claims for L to L kit, but that might be a stretch) and above 50,000 feet. I find this altitude a bit interesting, 50,000 feet seems a bit low if anything for a 2 stage flight to mach 3. You can see where the paint and even the composite skin were badly damaged by the friction created with the air stream above 2000 mph. Great work. Two stage rockets are far more efficient. Next step would be a P to N flight (CSXT attempt that failed to burn the upper stage) or even a Q to O motor. Either one of these would break 100,000 feet no problem. But clearly as this project shows... they need to have some serious heat protection. Either metal parts (generally the best idea despite the growing appeal of composites) or at least use some kind of high temp enamel.

Sunday, May 11, 2008

5-10 launch report

This was a small FAA notification launch. This is a central CT field, about 125 acres filled with trees and wetlands including a substantial stream. The weather conditions for the day were predicted to be: 30% chance of rain, cloudy, with winds 10 - 20 mph. The actual conditions were a bit different: winds were gusty and lower at ground level, around 5 - 15 mph, but seemed to be a constant 10 - 15 mph at altitude. There was significant flooding from previous rain, the field was loaded with water (but that was not a huge problem and provided a few comical "splashdown landings".) Around 1:00, the sun came out and it was suddenly a perfect day with somewhat reduced wind even. I was able to fly three rockets, burning a total of 5 motors (out of 7 attempted). All rockets came back in one piece, so that is the most important result. No hardware was lost or damaged. The first three flights - E11J in the SNP, F39T in the LOC Graduator, and D15T in the SNP again were perfect. The final flight for the day, a 4xD12 cluster in the Viper did not go exactly as planned, but the rocket was fine.

This is my SNP discussed previously, ready to go on an E11J-4. What a perfect flight! This motor was very old (5 years maybe?) and had some irregularities in the burn, but overall it was the perfect slow, graceful flight. I have one left, and three F12Js... and cant wait to use them again.


The LOC graduator here is ready for a nice flight on an F39T-4. This was a concern for me for several reasons. First, this rocket is getting old (20 - 30 flights over 9 years) and also getting very heavy. I was worried that the F39, essentially an E39 with a bit of extra power, wouldnt quite cut it. Also, the launch lug and rod didnt seem to get along for some reason. I had this problem on my viper as well, clearly I need to sand or even replace the lugs on these rockets... along with lots of other changes I need to make to upgrade my hardware for next time. In any event, with some sanding, the flight was great. Nice and low, but perfectly safe with great recovery. I will continue to fly this combo in the future.


This is a general view of the launch pads - this was a small event with 15 "pads" on 3 racks. The inner two are low and mid power, the outer pads are for higher power - 1/4th inch and up, and a rail.


Here is the motor block on the attempted 4XD12 flight. Not only was the launch lug too tight for the 1/4th rod (I was lucky enough to be given a 3/16ths, a pretty risky allowance I have to say!), but as you can see only two motors lit. My igniter setup was a bit sloppy, I will admit, and though it worked last time for 5 motors, this time it didnt work out. Next time I will have to do a better job, clearly. In any event, one motor lit right off, and the rocket was getting tossed off the rod to basically crash land. Around the end of the rod, the 2nd motor lit, and was just enough to launch the rocket to between 50 and 200 feet (yeah I was that nervous). The 3 sec. delay saved the rocket, and the chute ejected with a matter of feet to spare. The rocket was safe, but the two unused motors got wet and had to be destroyed. A small price to pay. But this is a good lesson, next time I will do a better job.

Overall, a great launch. Good to be back. I may attend a launch next month, check back for more updates.

Thursday, May 8, 2008

First Launch in several years.


I will be attending a launch this weekend, for the first time since NYpower 2004. This is going to be a low power, notification launch. That means there are some limitations - the rocket has to be under about 3 lbs, the motors installed must be under 80 newtons of thrust, max motor power is a G, there is also a propellant limit and a materials limit (no large metal parts), and there is a fairly low max altitude. But because I am planning on sticking to low and mid power, this is the kind of launch I will be doing for the foreseeable future (I sold some of my 38mm cases so I am really committed to lower power).

Pictured above is part of my collection as it was at the start of this rocketry page. Some of the rockets are gone, some are in deep storage. The three rockets highlighted with numbers are those that will make the trip this weekend.

Number 1 is the all time classic, the LOC Graduator. My oldest active rocket by far, and probably the best mid power rocket ever made. Just a simple 3FNC classic. This rocket has seen some heavy use, and it is nearing twice the production weight due to layers of paint and epoxy. But it still works, flying on as little as an E30 to as much as an H238. This weekend it will go up on F motors (I will discuss the motors below).

Number 2 is the Estes Super Nova Payloader. This is a great kit, made for motors from C to E power. Best on slower motors like the D12, E15, and others. This weekend it will fly on several different motors, probably some BP Ds and F12s. This kit has a clear plastic payload section, and is pretty big for an Estes kit. The SNP in the image is actually my old model, it is now gone and replaced with a new kit. (I did a better job this time...)

Number 3 is my LOC viper 4 - a cluster rocket with 4 24mm motor tubes. This rocket has never flown, so I hope to test it starting with 4 D motors. I will eventually (maybe this weekend, maybe next time) cluster two composite motors as well using my 24mm reload hardware. Two F39s, for example, would give nice power. Actually 78 newtons of thrust would just fit under the max for this launch... pretty nice to sneak that under the wire if I can. But I need to use two spent D motor cases as plugs before I use the two motor cluster - because the two unused tubes cant be left open; that would allow ejection gasses to escape and maybe prevent recovery. Why not 4 24mm reload motors? I cant afford that much hardware! Thats almost $200!

So I will be bringing a ton of black powder (BP) motors, including about 10 D motors. Great to cluster, as well as fly my SNP kit. I also have my 24mm composite reloads and they are:

D15-4T (3)
E11-3J (2)
F12-3J (3)
F39-9T (3)

The D, E, and F motors are right now only going to work in the SNP kit - they simply dont have the power or thrust to fly any other kit, and wont cluster very well either (J type motors, smoky formulation are hard to ignite reliably). I plan on building a new 24mm kit to take advantage of the full 24mm range of motors, something light and fairly small. The F39 will power the LOC graduator, as it requires this amount of thrust due to its increasing weight in old age. But note, the 9 sec delay is clearly wrong. I will have to replace with a shorter delay if flying the graduator, probably a 4 from the D15 if that seems to work. I also want to cluster the F39s as mentioned above. The E11s and D15s are also quite old - several years old. I have some concerns that they may be more likely to fail.

I will report back after the launch, and try to take some pictures or videos if I can.

Tuesday, May 6, 2008

Sugar Shot to Space





The goal of this project is to send a sugar motor rocket into space. This will be a fairly large rocket, and will contain two combustion chambers and one nozzle. In effect, it has the longer thrust duration of a two stage rocket, or a slower burning fuel, by having a booster motor and a sustainer motor that both share the same nozzle. After the burnout of the first motor chamber, a delay will burn through the bulkhead at the top end, igniting the next motor.

"Sugar propellant used by amateur rocketry experimentalists worldwide due to its inherent simplicity and safety, is not a high performance propellant. Therein lies much of the challenge of this project."

If this project works, it will be a huge step as only the third amateur rocket on record to get into or near space. (I include the RRS boosted dart as essentially a space launch, though technically it did not appear to hit space.) As of right now, only one team has ever made it to space... that would be the CSXT with the GoFast rocket (ugh what a name, the things you have to do for sponsors). However, the GoFast rocket had a huge amount of funding and was nearly commercial in nature. I would welcome this far more amateur attempt because it is far more of a grassroots type project. Yes amateur can be a good thing.

"Besides the extraordinary goal of sending a rocket into space, there are other equally important and more fundamental goals. This project is intended to be universal in scope with regard to involvement, and as such, participants from around the world are invited to join in this quest. It is hoped that the Amateur Experimental Rocketry community, which over the past decade has grown in size and in collaboration thanks to the internet, will bond even more closely -- to share our ideas, experiences, successes and failures. Other goals include expanded development of "sugar propellant" technology, leading to greater knowledge and enhanced safety of sugar propellant rocketry. And no one can argue that success of this project would provide incontestable legitimization of the remarkable "sugar propellant". Last, but not least, it is hoped that attention spurred by this project will promote an interest in science & technology and begin paving the way for future "rocket engineers" to take us further."

I hope that the Sugar Shot works, and that we will soon be launching amateur rockets to space on a regular basis.

*Update:

I have added a new image that goes over the general math for the expected Sugar Space Shot. The project is clearly behind schedule, by as much as 2 years, but there is hope that they will still finish. Most space shot rockets are never built, either people run out of money, time, or interest.



Note the expected mass fraction (amount of rocket mass made up by propellant): about .8. That would be very impressive, and would certainly improve their odds of using this kind of fuel (lower ISP) to get to space. If they get this rocket built to .8 mass fraction, that would impress me as much as the space flight! One big reason why professional sounding rockets do so well but ours dont (the Super Loki Dart is an M-N-O sized rocket that hits the edge of space) is the mass fraction issue. We need to begin to fix that if we want to keep pushing altitudes higher.

Also, you can clearly see in this description (as well as on the web page) that this rocket will have a single motor, that will burn in two stages. That is, the motor parts will be the same but with a middle bulkhead that will have a burn-through delay of 14 sec (I think after first stage burnout?). This will give the rocket some very valuable seconds of coast before the motor burn continues, this will greatly reduce drag loss and greatly increase altitude. Is this as good as a two stage rocket? Not even close, but like the boosted dart technique, it is still pretty darn good. A boosted dart R motor or two burn R motor will both do better altitude than your typical R motor (something like the Go fast rocket, but that was an S) that burns for say 14 sec. only. I have never seen this two burn motor technology used in solid rockets, but it has been done in the past. I do not know Sugar motor design very well at all. My question would be - why not simply use a moon or slot burner, or even an end burner in the grains? Would that not also help extend the burn? Would liftoff thrust be too low in that case?

Anyway, I will keep an eye on this inspirational project and make updates as needed. Probably in new posts as this one is about full.