60,000feet in 60seconds; MD N5800; Cesaroni Challenge

[THarrison]

So what happens if you come up short and don't get to the $4400 that you need? The money gets returned?

 

[patelldp]

FYI - If you guys buy the N5800 from Rob Dehate at AMW, he will throw in a third N if you break the record! That makes your prize much bigger.

Check out the Vendors forum, don't miss out!

 

[ClayD]

Bottom line is if you can't afford the ante stay out of the game.... Yeah I'd like to be driving a Lamborghini but I can't why? Cause I can't afford! it thats why.

I've said in other threads I may! be in this contest as well but only if the logistics permit it and cost is the #1 hurdle, I'm not about to ask a non team member or collaborator to fund my project, Nor would I be donating to someones else's.

Shoot,, owning a lambo aint ever stopped me from ripping an all wheel drive burnout... ;0
Now the S7, i just got to ride along.....(the one in the gillete commercial... )(funny story with it too"reads mr. hawwaiian troppics' daddy had a SMOKIN girlfriend...."

If we all placed our limitation within our own means, we would never increase those means....

I forget this thread was started by 18yearolds...... not a derogetory thing, just one where people who are doing things like they are, arent ones who have really probably ever had to fight tooo hard to make a circumstance work... (most people i know, call those the ramen noodle college days..)

If you are taking peoples money, do it with transperancy like clubs do, post a page of your expenditures with reciepts, and the donations recieved.(not the names.._) since your ethic or ghusto is under fire, no one can say you took 4800 and flew a 2,000.00 rocket, won 2000.00 in reloads and took the other 1800 for that Online playmate of the month membership.(or college class.)

we can all earn a bad rap on our own, i would hate to see you place yourself in a place where you get one by someone giving your money, then by a freinds aswaysion, gets that givers remorse and you get the bad wrap for it...

Just an idea.... and a forewarn...

Clay

 

[butalane]

But you can reliably assume that any given CTI motor will not cato. Better than 50/50 odds. And all of the RnD happened on their end. You buy one motor load and it is ready, and you know exactly what to expect from it.

Can be done, but has it? Id love to see this .6 - 228 Isp motor that worked the first time.

To sum up - the last thing a team of HS students needs is to be designing their own N for the first time. It won't happen in time or on budget for this project.

You're very critical of people who are providing experience based advice. While you're good at speculating your reliability predictions of experimental motors are simply made up. Yes, it has been done. Don't let the CTI kool-aid blur your vision.

In response to your second point, perhaps you couldn't achieve it but that doesn't mean it won't or hasn't happened. For comparison I designed, built, finished (with auto paint), and flew a 100% scratch rocket in one (1) month while I was in highschool that I funded out of my own pocket. It wasn't minimum diameter because I had no where to fly a minimum diameter rocket on the N motor that I designed, machined, mixed, and static tested (sub and full scale).

 

[New Ocean]

You're very critical of people who are providing experience based advice. While you're good at speculating your reliability predictions of experimental motors are simply made up. Yes, it has been done. Don't let the CTI kool-aid blur your vision.

In response to your second point, perhaps you couldn't achieve it but that doesn't mean it won't or hasn't happened. For comparison I designed, built, finished (with auto paint), and flew a 100% scratch rocket in one (1) month while I was in highschool that I funded out of my own pocket. It wasn't minimum diameter because I had no where to fly a minimum diameter rocket on the N motor that I designed, machined, mixed, and static tested (sub and full scale).

Didn't mean to be critical. Did your custom made N rocket (impressive to make in HS, particularly if you were under 18) get to 60,000 feet? And when you say built on your own, was it without significant help from others in the hobby or a family member?

Do you suggest that these guys spend the next month building their first EX motor, an N motor, and then flying it in a tiny rocket?

Note again that your advice does not apply here because this is specifically a competition to fly a single motor, the N 5800, to over 60,000 feet. Read the title of the thread.

Finally, do tell about the custom EX motors that outperform or even match the performance of the N 5800. Id like to know who is making them, and how they do it.

 

[patelldp]

I am curious as to how the N5800 has garnered this aura around it. Yes, it is a powerful and efficient motor.

Is it because people are flying rockets intended for M1939W's and N2000W's on it and expecting them to hold together? Is it because this motor is making people realize that model rocket philosophies don't work in the amateur rocket realm?

While this is not an amateur class rocket motor, a 4" N motor built on Estes philosophies will surely fail.

 

[k-rad du0d]

Has anybody tried this on a Mongoose 98? I was thinking a Mongoose 98 with Rouse-Tech fins would be good.

 

[maxvelocity]

I was thinking the same thing a goose with the rouse tech fin can should survive but would not be an ideal record setter. but i guess if you were the only one that survived you have the record.

 

[dixontj93060]

I am curious as to how the N5800 has garnered this aura around it. Yes, it is a powerful and efficient motor.

Superb marketing ploy from CTI--build the unflyable motor; create legend around the brand.

 

[MarkH]

Jeez, just chip in 10 bucks. That's like burning a pack of C6s or a CTI 24mm 1 grain. Succes or not, at least you'll get a youtube vid of it in a few months that'll be more impressive.

 

[Aksrockets]

I'll donate a few bucks. Bryce has been giving me advice on starting my own rocket class at my new high school, so I would consider it more like helping out a friend.

Alex

 

[Adrian A]

I am curious as to how the N5800 has garnered this aura around it. Yes, it is a powerful and efficient motor.

Is it because people are flying rockets intended for M1939W's and N2000W's on it and expecting them to hold together? Is it because this motor is making people realize that model rocket philosophies don't work in the amateur rocket realm?

While this is not an amateur class rocket motor, a 4" N motor built on Estes philosophies will surely fail.

Two reasons:

1. The N5800's Isp is significantly better than any other commercial motor in the hobby. It's also a big enough motor to get a well-designed rocket above most of the atmosphere, where rocket performance is more sensitive to Isp. These combine to make low-mass N5800 rockets sim about twice as high as most other N motors.

2. The speed that you can get flying an N5800 is high enough that aeroheating is a major problem for any light weight, minimum-diameter rocket that flys it. No commercially available composite tubes, composite fin stock, or nosecones are designed to handle the heating you would get flying this motor in an efficient rocket. That's why everyone who has tried so far has shredded.

I think a relatively heavy, low-risk rocket can be built to take the record. Use an aluminum fin can, fill the nosecone with weight, and make a high-temperature airframe that uses the motor as a coupler.

But the more interesting possibility to me, is what's possible with this rocket in a light rocket. Because it punches through the atmosphere so quickly, the optimal weight for the rocket for altitude is far below what can survive the flight, which is very different from say, an I or J record bird. So if you can make an 8-10 lb airframe survive this motor, you're looking at 80,000-100,000 feet. Can an 8 lb, composite airframe be made to survive? I think it's possible, with 600F-compatible resin and maybe with the right coatings.

 

[CarVac]

Adrian:
Interestingly, and somewhat randomly, the 1-grain CTI G115 White Thunder has a 232 second ISP, better than the N5800 (228). I've scoured ThrustCurve and that actually seems to be the highest of any hobby motor. Doesn't take any of the N5800's glory away, though, unless CTI manages to make a 6GXL White Thunder (which probably won't have as much impulse) which matches the G115's ISP.

 

[New Ocean]

I am curious as to how the N5800 has garnered this aura around it.

Also curious why so much resistance against it. Great mass fraction, Isp, in a 4 inch package... And it keeps eating up rockets that could fly on any other motor. It is not a mythical creature, and it should be no big deal getting a rocket to work on it. But it is still a very impressive motor. The reason why this thread keeps coming back to this single motor is because the thread is about a competition using this motor, and the plans of one team. So any boasts about some EX motor that is allegedly cheaper, faster, better... are great but irrelevant.

To make the discussion fair and balanced, perhaps we can bring the N4800 into the mix. It is also a very sick N motor, but is it still around?

So if you can make an 8-10 lb airframe survive this motor, you're looking at 80,000-100,000 feet. Can an 8 lb, composite airframe be made to survive? I think it's possible, with 600F-compatible resin and maybe with the right coatings.

Or you can just get a metal nosecone and fins and attach them to the motor and call it a day. Id say 1 kg fin can, 2 kg nosecone, 1 kg recovery and electronics is doable. 18 inch minimum frontal area vk nosecone. If the airframe is the motor case, you can also bake it all day if the fins need to be attached with epoxy instead of welding. That opens up a world of 700 degree cotronics (needs to cure at several hundred degrees.)

 

[k-rad du0d]

Would this stuff work? https://www.cotronics.com/vo/cotr/rm_adhesive.htm

 

[MClark]

Being confrontational is not the best way to get donations. I have received literally Tens of thousands in donations for contest prizes. I never argued with anyone.

It is sometimes easier to get a manufacture to donate that to get the monies to buy it. If you need carbon fiber call every place that makes or sells it. Have a packet that shows what you are doing and you would be surprised at what you will get.

If you want people to donate you need to be up front with what your project is. Tell us what you have done so confidence in your ability will be raised. Where do you launch so we can meet you and see that you are OK. And a real full name and a face to put to it will go a long way.

We are not anti youth, far from it, I run BALLS and we have had people younger than you show up want to go high and fast. Some of them post here and have succeeded not just in rockets but in their education, careers and life.

Mark Clark

 

[Adrian A]

Adrian:
Interestingly, and somewhat randomly, the 1-grain CTI G115 White Thunder has a 232 second ISP, better than the N5800 (228). I've scoured ThrustCurve and that actually seems to be the highest of any hobby motor. Doesn't take any of the N5800's glory away, though, unless CTI manages to make a 6GXL White Thunder (which probably won't have as much impulse) which matches the G115's ISP.

That Isp is for the fuel alone, which is still a useful metric when you want your rocket to carry its speed with some extra post-burnout mass. Especially in a G-impulse rocket that spends all its time in relatively thick air. Another metric for evaulating performance is to compare the total mass to the total impulse. The G115 has .72 NS/gram. Relatively high efficiency rockets like Aerotech's I600 have about 1 NS/gram. The N5800 has 1.38 NS/gram. Another relatively high efficiency motor is the J420, with 1.15 NS/gram. In N motors, there are some motors that come close in that metric, like the Aerotech N4800, which has 1.3 NS/gram. But its Isp is 197. The Isp and the impulse/initial mass are both important. If you had two motors with equal total impulse/mass, you would want the one with a higher Isp because although both motors would be going the same speed at burnout, the one with higher Isp would have lost less mass to propellant, so it's carrying more momentum to counteract drag losses.

 

[BLKKROW]

That Isp is for the fuel alone, which is still a useful metric when you want your rocket to carry its speed with some extra post-burnout mass. Especially in a G-impulse rocket that spends all its time in relatively thick air. Another metric for evaulating performance is to compare the total mass to the total impulse. The G115 has .72 NS/gram. Relatively high efficiency rockets like Aerotech's I600 have about 1 NS/gram. The N5800 has 1.38 NS/gram. Another relatively high efficiency motor is the J420, with 1.15 NS/gram. In N motors, there are some motors that come close in that metric, like the Aerotech N4800, which has 1.3 NS/gram. But its Isp is 197. The Isp and the impulse/initial mass are both important. If you had two motors with equal total impulse/mass, you would want the one with a higher Isp because although both motors would be going the same speed at burnout, the one with higher Isp would have lost less mass to propellant, so it's carrying more momentum to counteract drag losses.

Great information here, thanks adrian

 

[Adrian A]

Would this stuff work? https://www.cotronics.com/vo/cotr/rm_adhesive.htm

Its compressive strength is 1500 psi, and its tensile strength is probably less than that, but they don't say. It looks like it's intended more for easy gap filling for high-temperature applications more than high-strength bonding. I'm using Cotronics 600F laminating resin, (after building a curing oven for it) and I'm in the middle of experimenting with some coatings. This weekend I plan to fly a 2-stage 38mm rocket to about Mach 3.1 to test a few different high-temperature coatings.
https://www.rocketryplanet.com/forums/showthread.php?t=9606

 

[Tominator 2]

To give a little update on the design part of the project. We are going back and forth about whether or not to use the motor casing as a coupler or going with a more conventional way of simply using a CF coupler. The latter being less risky but needing more room. The first idea had to deal with he expansion of the motor casing which is can mess things up pretty quickly.

The other issue is the fincan. Considering that an aluminum fincan equipped N5800 shredded has me worried. Nevertheless, we are talking about 'slotting' the tube just a enough so that it doesn't go all the way through like a regular tube but helps in giving more surface area for the adhesive to bond too and helping to prevent shear. The 1/8" thick PR CF tubing is a little thin but I think we can mount brackets to the aluminum fins and then sand the bolts flush inside the body tube.

 

[butalane]

That Isp is for the fuel alone, which is still a useful metric when you want your rocket to carry its speed with some extra post-burnout mass. Especially in a G-impulse rocket that spends all its time in relatively thick air. Another metric for evaulating performance is to compare the total mass to the total impulse. The G115 has .72 NS/gram. Relatively high efficiency rockets like Aerotech's I600 have about 1 NS/gram. The N5800 has 1.38 NS/gram. Another relatively high efficiency motor is the J420, with 1.15 NS/gram. In N motors, there are some motors that come close in that metric, like the Aerotech N4800, which has 1.3 NS/gram. But its Isp is 197. The Isp and the impulse/initial mass are both important. If you had two motors with equal total impulse/mass, you would want the one with a higher Isp because although both motors would be going the same speed at burnout, the one with higher Isp would have lost less mass to propellant, so it's carrying more momentum to counteract drag losses.

This post is very confusing. Isp is not a "fuel alone" figure, it is really a system measure that takes into consideration factors of the propulsion system that affect the effective exhaust velocity beyond simply the propellant.

Are you wrapping inert mass of the total propulsion unit into your calculations? It seems like you're trying to include the mass ratio of a given motor in an ISP calculation, which I'm not sure is helpful when both factors are variables in the rocket equation to begin with.

Two rocket motors with identical impulse/mass ratio .... so ISP?

Have you done a numerical/any analysis to conclude that drag is the dominating negative factor in the rocket equation at the high altitudes you are proposing flying, so much so that including more weight would help you and not increase Fg enough to hurt maximum altitude? Your implication of a low density ISP is surprising as this is often a sought after factor that drives the initial mass/final mass ratio up and increases the delta V capability. A quick run of the numbers shows it is possible to achieve a higher delta v with a lower ISP propellant if the mass ratio was favorable.

 

[MarkH]

Adrian:
Interestingly, and somewhat randomly, the 1-grain CTI G115 White Thunder has a 232 second ISP, better than the N5800 (228). I've scoured ThrustCurve and that actually seems to be the highest of any hobby motor. Doesn't take any of the N5800's glory away, though, unless CTI manages to make a 6GXL White Thunder (which probably won't have as much impulse) which matches the G115's ISP.

New Blue Thunder has about 225 ISP, and the new Propellant X reload is 229.

 

[CarVac]

Actually, the G138, which is New Blue Thunder, is 229 officially, but 241(!!!!!) if you go by the 166 Ns impulse given in the thrust curve, while the new Propellant X reload is 220, and 222 based on the impulse in the thrust curve. I just calculated these based on 9.8 m/s^2 gravity.

The G138 also has terrific volumetric impulse. It's fairly tiny compared to other full G motors.

 

[Rocketman248]

The new P24 1G E31WT is 237, and the P24 3G F51CL is 231.

 

[BsSmith]

I'm not sure if you have looked into this or not, but what about the thermal properties of aluminum? The tensile strength of 7075 aluminum starts to rapidly drop once you hit about 300 degrees F. If your making fins out of it, you could have some problems. Have you done any calculations as to how hot the fins will get? Have you looked into using other materials for fins? I'm sure that you could make a composite fin work if you use the right resin. You could also use a different metal. If your into engineering, you may be able to make a stainless steel fin lighter and stronger than a comparable aluminum fin.

 

[edwinshap1]

To the above question. The leading edge will heat up to at least 1000F, but the heat transfer rate of aluminum is fairly good, though not as good as copper. I've been doing a fair amount of research for my school's liquid engine. The combustion chamber in that is 0.1" aluminum and will be cooled so it doesn't melt within a second of ignition.

Almost 80% of the thermal heating on the fins will take place on the leading edge, but the rest of the fin is a fairly large heat sink, so as long as we don't stay beyond mach 3 for more than a couple seconds, we shouldn't have any issue with physical deformation of the aluminum due to heat stress.

We know there are alternate methods, including using phenolic ablative leading edges seated against a composite fin core, which is our second option if the aluminum proves to be too troublesome. Stainless weighs ~3 times as much as aluminum, so to make a fin of comparable weight, it would need to be 1/12" thick, which is not feasable. It is, however, to use stainless as the leading edge, and a composite core.

 

[MarkH]

Actually, the G138, which is New Blue Thunder, is 229 officially, but 241(!!!!!) if you go by the 166 Ns impulse given in the thrust curve, while the new Propellant X reload is 220, and 222 based on the impulse in the thrust curve. I just calculated these based on 9.8 m/s^2 gravity.

The G138 also has terrific volumetric impulse. It's fairly tiny compared to other full G motors.

Cool. I was using the impulse and weight info from the AT instructions and 10 m/s^2 for gravity because I was lazy.

 

[Jeroen_at_CTI]

The new P24 1G E31WT is 237, and the P24 3G F51CL is 231.

The ISP is calculated from the total impulse and the propellant mass. On the smaller motors there is a significant contribution from the delay/tracking smoke to the thrust. There is also consumption of liners etc. that increases the thrust. If you calculate Isp based on mass delta (loaded - fired) you get a more accurate picture.

Jeroen

 

[Adrian A]

This post is very confusing. Isp is not a "fuel alone" figure, it is really a system measure that takes into consideration factors of the propulsion system that affect the effective exhaust velocity beyond simply the propellant.

I meant that the Isp figures provided are based on the mass of the fuel alone, so the Isp will stay the same even if the case mass goes up. I was trying to explain why Isp alone doesn't tell you everything you need to know about the overall performance and efficiency, and I was doing a poor job of it.

Are you wrapping inert mass of the total propulsion unit into your calculations? It seems like you're trying to include the mass ratio of a given motor in an ISP calculation, which I'm not sure is helpful when both factors are variables in the rocket equation to begin with.

Thinking about this some more, I think the best way to explain why the N5800 is "special" is just to use the rocket equation to show what delta-V the motor could provide on its own. Delta velocity = Isp* G * ln (Mfinal/Minitial). G is just the gravitational constant, 9.8 m/sec^2 if you're working in SI units. You can plug in motor data from thrustcurve for any motor and this equation will tell you what the burnout velocity would be if your airframe didn't weigh anything or have any drag.

For comparison:
N5800 2095 m/sec Isp: 228
N1100 1814 m/sec Isp: 210
N4800 1557 m/sec Isp: 197
G80 1481 m/sec Isp: 223
I600 1408 m/sec Isp: 186
G115 859 m/sec Isp: 229

I'm curious now if there are any motors on thrustcurve that have a higher delta-V. I doubt it but I haven't searched comprehensively.

 

[Reinhard]

I'm curious now if there are any motors on thrustcurve that have a higher delta-V. I doubt it but I haven't searched comprehensively.

See here, particularly the last of the attached files.
https://www.rocketryforum.com/showthread.php?29967-High-Impulse-to-Mass-Motors&p=270127#post270127

Reinhard