Nytrunner
Pop lugs, not drugs
24 does stand for 24mm diameter, but the 40 stands for the notional impulse (Newton-seconds) that the case holds. (I know, it has an F motor reloads, but primarily D/E reloads go in that case)
CG and CP which where how to figure on a Saturn V estes Rocket
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24 does stand for 24mm diameter, but the 40 stands for the notional impulse (Newton-seconds) that the case holds. (I know, it has an F motor reloads, but primarily D/E reloads go in that case)
JPalmer621
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This is on an E30. My experience with the E20 was not as positive as others so I put some more power in. I have also launch this rocket on a F44. Please don't try a D motor just not enough power. I have added some nose weight of 2 thick washers. And my scatch Skylab on a E30 too.
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JPalmer621
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Here are the instructions from a very old Saturn V kit. It uses clear add on fins. Two pieces of clear plastic (several choices out there) This way you can keep more semi scale fins.
Thanks for the info on the Saturn V I thought mine was the original rocket but I see the cluster of engines which mine is not. I just enlarged my fins with balsa. I'm sure its due to under power and my CP /Cg is not stable I will need more weight up top.'
Thanks again sorry I missed the message.
Thanks
Sterk03
Thanks again sorry I missed the message.
Thanks
Sterk03
Ok so time for an update to my Saturn V woes... SO I took all of the info into account and it did help but I still don't understand how Estes can sell these kits and expect them to fly on the motors they give you in the instructions. I guess also I need more info on several comments about building it heavy...If you build it the way the instructions call for and the materials in the kit then it should be a flying rocket. Not lighter or heavier then originally planned. So if you do this it should go on the advertised motor and the fins given in the kit. So I started to modify my 1990's circa Saturn V model to larger fins and also due to your info on the thread added slowly some weight to the nose cone which was not called for and if you were building it light then no weight at all. Ok but it was no way near stable without adding weight and also larger fins. It was to fly on a D12-3??????? yea ok. So last month I got 2 great flights out if her with a AT E30-4T and it went to 277 feet. I would say this is the bare minimum for chutes etc. My first launch last week I used a E30-4t and had a good flight . But now remember the fins are larger and its about 4-5 oz over the unstable weight so I'm not going to get any higher. So next flight I use a F44-4W so I'm thinking this will really go higher. Well it did not and it actually looked like it went lower then the E30. So I'm new to Aerotech so I need to do some homework on the numbers and codes, it made no sense to me. So I guess what I'm getting to is too much put on stability that too much weight is added. It seems like once an E30 was introduced it was very stable that maybe too much CG over CP that was not needed maybe fine tune it. I'm getting at the new SaturnV was launched and I used a F32-6T. It was my mistake missing the 6 sec but it would not have mattered. To get your tube cylinder size in seperation of CG/CP you have added too much weight that it comers in almost 1.5 lbs???? SO thinking that the F32-4 or 6T would get her up there was wrong it did not...so how in the world can an estes motor ever expect it to fly as built. The F32 says 19 oz lift off....which it did but not going anywhere fast. So again going to a higher engine or reduce some weight and lose some stability just to get it to fly. So if your setting the CP and CG to where it is too be then how can you call it a heavy build if its according to the plans of rocketry. I'm just frustrated that Estes is in la la land. A kid like me in early teens building the Saturn V according to plans and no use of Rocksim and building it correctly has no hope of a successful flight. Ok I'm done. I will be looking for a bigger engine that can fly this bird to where it should fly. Sterk03 I'd like to see the Saturn fly on a E16...that is stable (with a lot of added weight and stock fins)
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I don't know which Estes kit you are using, but the one my nephew built had the engine recessed about 1 diameter into the airframe. It was relying on Gas Dynamic Stabilization to fly straight, not the fins. As soon as the thrust ended, it went unstable, which is to be expected on such a model. The point here is that if the engine is recessed and the rocket is using GDS to keep it stable during the thrust phase, a swing test will almost certainly fail because the fins aren't providing the stabilization, it's the airflow into the fin can at the outer edge of the airframe that is replacing the exhaust and providing pressure on the inside of the fincan structure to keep it stable.
So, the answer for stability on a Saturn V depends on the design. Most models that use the fins for stabilization have large clear fins. If the model has scale fins, it's more than likely that the engine mount is recessed and GDS is providing the stability.
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Doesn't GDS require vent ports into the void area? The Estes Saturn V doesn't have that...
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When you are picking engines you need to understand the interplay between Max Thrust (aka, get it off the pad), average thrust, total impulse and burn time.
For the engines you were using, the F32T has the same average thrust as the E30T, a bit higher peak thrust, but burns longer, hence higher total impulse. Since the average thrust is the same as the E30T, it will not go fast, just burn longer (and presumably go higher). The F44W has the same max thrust as the E30T (same oomph off the pad) with a higher average thrust for the same burn time, so a bit more total impulse than the E30T, but only 1/3 more.
There are other factors that could come into play. This model is really draggy, so don't expect it to go a lot higher on a slightly bigger engine. Draggy rockets don't necessarily fly linearly in altitude with bigger engines. How about flight conditions? How windy was it for each flight? Did one flight weathercock more than the other?
Your best bet is to download Openrocket, build out the model in it (or use an existing file), measure the CG and weight, override them in the program, then sim the motors you want to use. If the sim is unstable with an engine, you can play with adding nose weight in the model to find out exactly how much to add to make it stable and maximize altitude. If it is overstable, you can trim weight.
There is no exact answer. Each rocket and each flight of each rocket is different.
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Vent ports are the best way to ensure the airflow, but they are not necessary. There is a whole lot of material on this elsewhere in the forum and on the internet. I have the doc on it. PM me if you want a copy.
1 diameter is the minimum you want to use, yet at 4 diameters the airflow is completely choked off, so you have to understand the physics of it. I use 1 diameter AND vent ports just below the motor nozzle to ensure good airflow on my models.
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Interesting. For what it's worth, I didn't recess the motor on mine, except by maybe 1/4" to get a good fillet on the centering ring.
Regarding your issues with motor performance and stability, I cannot recommend strongly enough that you check out G. Harry Stine's Handbook of Model Rocketry. Obviously some things have changed in model rocketry since the most recent 7th Edition came out in 2004 (3D printing and far more advanced avionics among them), but there's a chapter dedicated solely to the design, construction, selection, use, and operation of the model rocket motors that form the core of our hobby. Stine has a way of explaining the relevant concepts and techniques on a level that is readily understood even by younger or more reluctant readers, and it's littered with funny stories from Harry's decades of rocket range experience.
I still have my copy from when I was first getting into flying rockets around 2005 or so and it has proven to be the most valuable thing in my range box, right up there with my knife and a bottle of CA glue.
It's available for Kindle for $17 or you can pick up a physical copy for ~$20. Many, many kits and motor packages are more expensive than that.
In my opinion, it's better to drop that small amount of cash for something useful than to blindly waste money on motors that won't work for your project because they're not what you need. The book will help you figure out what to look for in other projects as well as this one.
If you have it already, go ahead and crack it open. Read the motor chapter and the stability chapters carefully, see if you can figure out what Mr. Stine is trying to explain. And if you get stuck, you're more than welcome to bring it to the forum. I'm sure a lot of users here would be glad to explain it in a different way that might work better.
But to actually contribute something of my own here, I'll say this: With a model this heavy, you'll want to select something that has a high initial thrust. This initial thrust value won't be part of the motor code (the 30 in E30, for example, indicates average thrust instead, which is an entirely different value) but you might be able to find the initial thrust on ThrustCurve.org or perhaps in the certification documents available from the National Association of Rocketry, the Tripoli Rocket Association, or other relevant certification organization. The Tripoli Rocket Association (a large sanctioning body mainly focused on high-power rockets but also catering to model rocketeers) has a set of Range Safety Officer guidelines that recommend a 5:1 ratio of initial thrust to weight.
You may have to fiddle around with the parameters to find a motor and nose weight configuration that meets the requirements for a safe flight. If you can find one that works, modify your model accordingly and try to stick with that configuration (or something else that just happens to be compatible) as much as possible.
Scale models are sometimes tricky fliers. The big man-rated orbital launch vehicles at the Cape and at SpaceX typically rely on thrust vectoring, reaction jets, and other guidance methods that simply don't scale down to model rocketry. Their complex geometry also usually requires heavier construction methods in a scale model. Sometimes they amount to little more than glorified display stand models that have rocket-powered flight as a secondary capability, just so you can say "Yes, I flew that".
Downscales of sounding rockets designed to collect data from the upper atmosphere sometimes work better, as the originals tend to be smaller and simpler in appearance. The Nike Smoke, for example, is pretty popular for detailed scale modeling.
If raw performance is what you're looking for, you're probably better off looking at a sport model. Both the Estes Gnome and Estes Alpha III are great little kits with easy assembly, impressive performance on almost any motor that will fit in them, and very little if any tinkering required to get them flight-worthy. I've built several of each over the years.
This isn't to discourage you from tinkering with and flying that Saturn. By all means, go for it if that's what you really want out of flying model rockets. I'm just throwing this out there as an alternative and perhaps more practical method of achieving your goals. It's up to you to decide where to go from here.
Just to add to what @smstachwick said, I have a somewhat opposite experience that I can relate. I just restarted in this hobby in January 2020. Later that summer I built an Estes V-2 for my brother-in-law (the bigger one with the 24 mm D/E engine mount. I asked for help and sure enough @James Duffy shows up and notes that the Estes fins are larger than scale. I think you're a scale guy so maybe you can relate - once you see something like that, you can't "unsee" it. James assured me it would fly stably with the smaller scale fins and even sent me a template! (Thread and eventually pics here!)
But (not knowing how old you are exactly) when I was in high school 50 years ago, I had learned how to design using the CG and CP "cardboard cutout" method. So for my own edification, I worked up a design file. To my horror, the CP came out above the CG. Hmm. I know James Duffy would not deliberately mislead me... maybe I'm wrong. So I decided to do a swing test. Full flight configuration, E motor. And it passed! I even tried flying it backwards and is swung around to stable forward flight every time! Awright now, what the heck?!?! The laws of physics should work!
Now another 50 year-flashback. As a freshman engineering student in 1973, I encountered a book from MIT Press at the Pitt bookstore, "Topics in Advanced Model Rocketry." Though I'd had calculus and physics in high school, I was disappointed that I could not understand it. Then the craziness of life intervened (coupled with some of my own craziness) and soon I am married and the book sits for 50+ years. During that time, I eventually finished my engineering degree and became a mechanical engineer; I just retired from 30+ years in that sport, but retain my professional license.
Well, like I said, the laws of physics should work. Well, actually, they do work. They just don't care about our calculations. So on this-here-thread I reported this anomaly and they noted that the cardboard cutout method for CP is too conservative - rockets don't fly sideways, as one fellow humorously noted! The Barrowman method is more complex, but also more accurate - and it was the one descibed in my book!
As luck would have it, I was going on my last field job before retirement, training a new engineer to do a structural vibration test on an electrical generator end winding. So I took the book to read on the airplane. Ah, the difference an education makes! I flew through the 1st two chapters like an anti-missile missile! The whole method was basically the same math I used for vibration work all these years! And so now I have the confidence that the V2 will fly straight, and by glory, it did! (and drifted into a tree, but we got it down with an extension ladder and a 16. ft tree pruner!)
The whole point of my sermon is, if you're still in high school, make the most of it. I had a lot of family trouble in 9th-10th grade and nearly flunked my second-year algebra. But when the big crisis passed, I realized my future was on me, and knuckled down and learned as much as I could. In college, same deal - those are the tools in your toolbox, you don't go to the store, take a tool set to the checkouts, pay for it and start handing them tools back because you don't think you'll need them!
And, any "hands on" experience you can squeeze in -shop classes, etc. - do so. You've obviously got some good skills already just building a Saturn V. With these combinations of skills, you will do good not only in rocketry, but in life. Never take education for granted!
@Ez2cDave is working on a PDF edition of said book, perhaps some day you will be able to add it to your library. It is the basis for much of what is in OpenRocket and Apogee's Rocksim (at least the subsonic part). As an analyst, I like knowing the math behind the computer solution. I can't tell you how many times I've seen youngsters fool themselves blind not raelizing what they were modeling with their simulations, particularly finite element analysis, and also by not having a good physical grasp of what to expect from their model.
</sermon off> Best to you, hope this helps!
But (not knowing how old you are exactly) when I was in high school 50 years ago, I had learned how to design using the CG and CP "cardboard cutout" method. So for my own edification, I worked up a design file. To my horror, the CP came out above the CG. Hmm. I know James Duffy would not deliberately mislead me... maybe I'm wrong. So I decided to do a swing test. Full flight configuration, E motor. And it passed! I even tried flying it backwards and is swung around to stable forward flight every time! Awright now, what the heck?!?! The laws of physics should work!
Now another 50 year-flashback. As a freshman engineering student in 1973, I encountered a book from MIT Press at the Pitt bookstore, "Topics in Advanced Model Rocketry." Though I'd had calculus and physics in high school, I was disappointed that I could not understand it. Then the craziness of life intervened (coupled with some of my own craziness) and soon I am married and the book sits for 50+ years. During that time, I eventually finished my engineering degree and became a mechanical engineer; I just retired from 30+ years in that sport, but retain my professional license.
Well, like I said, the laws of physics should work. Well, actually, they do work. They just don't care about our calculations. So on this-here-thread I reported this anomaly and they noted that the cardboard cutout method for CP is too conservative - rockets don't fly sideways, as one fellow humorously noted! The Barrowman method is more complex, but also more accurate - and it was the one descibed in my book!
As luck would have it, I was going on my last field job before retirement, training a new engineer to do a structural vibration test on an electrical generator end winding. So I took the book to read on the airplane. Ah, the difference an education makes! I flew through the 1st two chapters like an anti-missile missile! The whole method was basically the same math I used for vibration work all these years! And so now I have the confidence that the V2 will fly straight, and by glory, it did! (and drifted into a tree, but we got it down with an extension ladder and a 16. ft tree pruner!)
The whole point of my sermon is, if you're still in high school, make the most of it. I had a lot of family trouble in 9th-10th grade and nearly flunked my second-year algebra. But when the big crisis passed, I realized my future was on me, and knuckled down and learned as much as I could. In college, same deal - those are the tools in your toolbox, you don't go to the store, take a tool set to the checkouts, pay for it and start handing them tools back because you don't think you'll need them!
And, any "hands on" experience you can squeeze in -shop classes, etc. - do so. You've obviously got some good skills already just building a Saturn V. With these combinations of skills, you will do good not only in rocketry, but in life. Never take education for granted!
@Ez2cDave is working on a PDF edition of said book, perhaps some day you will be able to add it to your library. It is the basis for much of what is in OpenRocket and Apogee's Rocksim (at least the subsonic part). As an analyst, I like knowing the math behind the computer solution. I can't tell you how many times I've seen youngsters fool themselves blind not raelizing what they were modeling with their simulations, particularly finite element analysis, and also by not having a good physical grasp of what to expect from their model.
</sermon off> Best to you, hope this helps!
I also struggled with Barrowman calculations. I ended up graduating high school without a lot of classes one would typically need (long story, you do not want to hear about it) so I’ve always felt since then that my education was incomplete despite that diploma hanging up on my award board.
I don’t have much of a mind for mathematics to begin with, so when I opened up Stine’s book and flipped to the Barrowman method appendix and looked at the hideous calculations and measurements I’d need to do just to get the terms for one of the recent projects I was working on, my brain basically turned to mush. Not gonna happen.
I was pleasantly surprised to find that RockSim was much easier to get up and running and that there was an option to calculate CP with Barrowman’s equations instead of RockSim’s algorithms. I did notice it seemed to be a hair on the conservative side though, at least with the kits I’m running in it.
Wow... your story could have been mine, which you also don't want to hear about! Fortunately I had some good people that I didn't even realize then were looking out for me.
Now I'm wondering what Tim Van Milligan has come up with vs. Mr. Barrowman.
Thanks to all a lot of material to digest. I will just hit a few points that stick out and then re read it.
1. Yes I have the book and going to the beach next week and taking both of them and start reading them.
2. The Estes Saturn V I have is two. The same 1/100 scale one from around 1990's and the other the new 50th anniversary version. The old one is flying well now with larger fins on a E30-4T and stable but much higher weight then I believe it should be. The engine on it is recessed about 3 inches and so is the newer version so I'm not sure on the GDS but it is built to spec from Estes, no other modification is mentioned. I have the newer one with the fins that came with the rocket and will try it that way first.
3. I heard mention of the CP CG and cardboard cutout which I did and my take on that were you saying that maybe it builds more space in the distance of the two then needed??? so the weight in the nose could be lowered.
4.Back to my rant, I guess if I
m building an experimental rocket then I need rocksim or more testing but this is a big business making a lot of money building kits that should fly ok out of the box if following the instructions and if it need to list a cg then list it or info on how to help stability if needed. I would never be able to digest that info from a sim online at an ealry age.
5. I do have many other rockets and have not had an issue with any of the present problems and many fun launches.
6. I followed the space program from an early age so that is why I want to build and launch all the rockets and had a fair flight in the Gemini-Titan getting both motors to fire at once and a descent altitude but now I want to go higher.7.
I was told by Estes go to youtube and look up Estes Shuttle and see that they do fly successfully...well the first one I find played it and it plowed into the ground worse then mine and it was such a beautiful paint job...so still seeking answers on this model also?
7. Yes I know I am trying to learn more about the Aerotech motors and what the numbers all mean so that was a good education on them and I was trying to compare all the info they provide but need more study on it.
I will be getting rock sim and give it a try, I just recently got back into rockets but do not have the time to get better too many other things but that might change.
8. Mentioned before I'm not aware of any 1/100 scale Estes Saturn V that does not have the engine recessed?
Ok thanks again and I will continue with the process as the old Saturn V is the test version and I hope I figure it all out so the first flight in the new one is golden.
Thanks again to all.
Sterk03
7. My background is aviation since age 13 and now retired so I have that background but it is not rockets that's for sure.
1. Yes I have the book and going to the beach next week and taking both of them and start reading them.
2. The Estes Saturn V I have is two. The same 1/100 scale one from around 1990's and the other the new 50th anniversary version. The old one is flying well now with larger fins on a E30-4T and stable but much higher weight then I believe it should be. The engine on it is recessed about 3 inches and so is the newer version so I'm not sure on the GDS but it is built to spec from Estes, no other modification is mentioned. I have the newer one with the fins that came with the rocket and will try it that way first.
3. I heard mention of the CP CG and cardboard cutout which I did and my take on that were you saying that maybe it builds more space in the distance of the two then needed??? so the weight in the nose could be lowered.
4.Back to my rant, I guess if I
m building an experimental rocket then I need rocksim or more testing but this is a big business making a lot of money building kits that should fly ok out of the box if following the instructions and if it need to list a cg then list it or info on how to help stability if needed. I would never be able to digest that info from a sim online at an ealry age.
5. I do have many other rockets and have not had an issue with any of the present problems and many fun launches.
6. I followed the space program from an early age so that is why I want to build and launch all the rockets and had a fair flight in the Gemini-Titan getting both motors to fire at once and a descent altitude but now I want to go higher.7.
I was told by Estes go to youtube and look up Estes Shuttle and see that they do fly successfully...well the first one I find played it and it plowed into the ground worse then mine and it was such a beautiful paint job...so still seeking answers on this model also?
7. Yes I know I am trying to learn more about the Aerotech motors and what the numbers all mean so that was a good education on them and I was trying to compare all the info they provide but need more study on it.
I will be getting rock sim and give it a try, I just recently got back into rockets but do not have the time to get better too many other things but that might change.
8. Mentioned before I'm not aware of any 1/100 scale Estes Saturn V that does not have the engine recessed?
Ok thanks again and I will continue with the process as the old Saturn V is the test version and I hope I figure it all out so the first flight in the new one is golden.
Thanks again to all.
Sterk03
7. My background is aviation since age 13 and now retired so I have that background but it is not rockets that's for sure.
Good to know.
The Aerotech motor designations run on the same system as the Estes ones. A letter indicating total impulse (a D motor is more than 10 but up to 20 Newton-seconds of total impulse), a number to indicate average thrust in Newtons, a dash, a second number to indicate delay time in seconds. Aerotech also adds a non-standard letter at the end to indicate the propellant type, but this is more for cosmetic purposes or differentiating motors with different thrust curves that would otherwise have an identical designation.
The thing to remember is that the advertised total impulse figure, the letter, is a range, not a specific discrete value. The top of any given range is almost (never exactly, but almost) twice the total impulse of the bottom, so even two different motors sharing a letter designation can vary quite a bit in the total impulse they deliver.
Average thrust numbers may also be fudged a bit by the manufacturer to differentiate between motors that have the same total impulses and average thrusts but with different thrust curves. The Estes A10 and A3 have similar average thrusts and total impulses (in the neighborhood of 3 Newtons of average thrust and 2.5 Newton-seconds of total impulse) but the A10 has a higher maximum thrust closer to 12 Newtons, which is better for getting heavier models off the pad or if you just want a smaller model to really zoom up. But the shorter delay time on the A10 compared to the A3 (they only come in 3- and 4- second varieties, respectively) means that the vast majority of small rockets will go higher on the A3. It’s not immediately obvious but that’s where doing your homework and understanding these figures really pays off.
Delay times are fairly straightforward. A shorter one is good for heavier models that won’t go as high, but you take the risk of a high-speed deployment destroying the recovery device on the way up if you put such a motor in a very light airframe. A longer delay is good for very light and/or fast models (minimum-diameter kits, large clusters, or upper stages, for example) but if you put them in a heavier airframe you risk the rocket coming back on an unsafe ballistic trajectory with no parachute, and you also have the risk of high-speed deployment on the way down. Because of the dual risk was with a long delay, I usually start short and work my way up, retiring a motor type from duty in a particular airframe if the deployment looks questionable.
Also please understand that scaling down a big space launch vehicle and making it into a kit suitable for the average modeler, with manufacturing tolerances and supply issues and tooling challenges and stuff like that to overcome, is a not an easy thing. Sometimes stuff goes into production with known bugs that can’t be solved for technical, legal, or financial reasons. Since responsibility for legal, safe, and successful flight ultimately lies with the modeler exercising good judgement, the main thing dictating which kits are made available and which kits aren’t is the manifacturer’s interpretation of market forces. And when you’re scaling the launch vehicle that propelled humanity to the moon all those years ago, you can bet that there will be intense market interest in that product even if its flights tend to be low-performance or tricky to get right. Estes has a section on their website chronicling the development of the Saturn V kits, I think it’s kind of interesting and I suggest checking it out.
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There is a phrase, “the exception that proves the rule.” Estes produces great rockets overall, but has a tendency to come out with some that are at best borderline and at times frankly underpowered even with the largest Estes motors that will FIT in the provided motor mount. Other classics include the MIRV (two stage with one booster and three sustainers, great concept but with an 18mm mount in the (solid plastic) booster fin can and no way to upsize it, miserable execution), the OutLander, Venus Probe, Exo-Skell, and Porta-Pot Shot are some others begging for upsized motor mounts.
you are not alone when you wonder, “What in the world were they thinking?!” at times.
you are not alone when you wonder, “What in the world were they thinking?!” at times.
I understand that the BP motors produce additional thrust at the high-elevation Penrose, Colorado facility and the airframes obviously experience less drag there. My guess is that some of them were tested there without accounting for performance at lower elevations.
Of course this data is some 20 years old and they’ve had plenty of time to increase the scope of their design studies. If any kits in production suffer from these kinds of performance issues, I genuinely don’t know why they haven’t been fixed or pulled. Perhaps they think it more economical to risk lower performance with limited testing than to expend more resources on improving the test procedures.
@Sterk03, my apologies for misunderstanding your age. I hope you enjoy your retirement! You've earned the right to rant, we're OLD! I'm still trying to work mine out; since I retired last month I've continued to work like a madman, just without pay! Maybe sometime a kid will run across my little sermon and be inspired!
@BABAR, I agree, my Venus Probe flys much better on a Quest D16-4 and I'm thinking about using a full Aerotech RMS 18/20 D load on it. Gotta figure out delay drilling. I think @smstachwick might have a point about the elevation in Colorado. I hereby volunteer to have Estes send me some kits for testing at 1000' field elevation!!!
@BABAR, I agree, my Venus Probe flys much better on a Quest D16-4 and I'm thinking about using a full Aerotech RMS 18/20 D load on it. Gotta figure out delay drilling. I think @smstachwick might have a point about the elevation in Colorado. I hereby volunteer to have Estes send me some kits for testing at 1000' field elevation!!!
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I've never tried drilling delay on the QJets. Didn't even think it was on option. Let me know how it works out.
I believe he is talking about drilling the RMS D load, not the Q-jet.
Correct. I bought 7 sec delays and I think that would be too long, shooting for more like 5 on full "D" impulse.
I shall volunteer for sea-level testing.
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You win! Sea level < 1000 ft. elevation!
OK OK I mis-spoke I know CG is above CP.. I got it. I've been busy with life but let me answer a few questions. I figured out the CP with the cardboard cut out I have not ventured into the rocksim but now I know I will have to. So if I have a proper CP and it is below the CG and I put in the engines Estes said should work and the sale of the rocket is based on it it will fly. I did not overweight mine I did not slop paint on it I did not attach heavy metal objects to it but it would not fly until I experimented with larger engines then Estes called for...That's my point..... I balanced the rocket to acquire the CG with everything loaded on the rocket like it was going to fly. I was not using heavier motors then suggested and yet it was underpowered.
I understand about the F24 Aerotech motor and you load it I got that and have one but not to that stage yet. I don't want to get into it but someone mentioned about cg being in front of cp by one body diameter tube size if you do that on a Saturn V you have to add a lot of weight into the nose to make it stable and now how is that to have been flown out of the box with the suggested engines. Kits other then Estes provide a cg if built as shown, Estes gives no advice or any info on cg or stability???? I'm on some other thread about my two versions of Saturn V and the amount of weight you need to make it stable by the information you have provided, rocksim or no rocksim now its so heavy trying to get off the pad and reaching 250 feet and this is on an Aerotech engine. Ok one area I need more understanding cause trying to read about the aerotech engines the different blue,white,black.. and all the numbers given and how one article talks about power to get a heavy rocket off the pad but it does not have p-ower to accelerate, or this color will accelerate or for heavy weight, so ok what numbers are you using to get a more powerful engine(one that will liftoff the rocket and accelerate to a safe altitude with ample room for the delay to happen and then the chute to come out and not make a hail Mary landing????? They have numbers in 8 different categories and weight of max liftoff??? so how do you look at all the numbers and say this has enough total power to launch this rocket. I used a E30-4T and it got the Saturn V to 250feet, but I wanted more room and so I tried a F44-4W and a F32-4T but these did not increase the altitude what so ever so I might as well use a E30 Aerotech so what did I read wrong and how do you pull out the real number of these engines other then by experimenting...I'll take any advice. Ok enough for now
Sterk03
I understand about the F24 Aerotech motor and you load it I got that and have one but not to that stage yet. I don't want to get into it but someone mentioned about cg being in front of cp by one body diameter tube size if you do that on a Saturn V you have to add a lot of weight into the nose to make it stable and now how is that to have been flown out of the box with the suggested engines. Kits other then Estes provide a cg if built as shown, Estes gives no advice or any info on cg or stability???? I'm on some other thread about my two versions of Saturn V and the amount of weight you need to make it stable by the information you have provided, rocksim or no rocksim now its so heavy trying to get off the pad and reaching 250 feet and this is on an Aerotech engine. Ok one area I need more understanding cause trying to read about the aerotech engines the different blue,white,black.. and all the numbers given and how one article talks about power to get a heavy rocket off the pad but it does not have p-ower to accelerate, or this color will accelerate or for heavy weight, so ok what numbers are you using to get a more powerful engine(one that will liftoff the rocket and accelerate to a safe altitude with ample room for the delay to happen and then the chute to come out and not make a hail Mary landing????? They have numbers in 8 different categories and weight of max liftoff??? so how do you look at all the numbers and say this has enough total power to launch this rocket. I used a E30-4T and it got the Saturn V to 250feet, but I wanted more room and so I tried a F44-4W and a F32-4T but these did not increase the altitude what so ever so I might as well use a E30 Aerotech so what did I read wrong and how do you pull out the real number of these engines other then by experimenting...I'll take any advice. Ok enough for now
Sterk03
Rocksim or OpenRocket.
Or, get a rougher but still very useful number with Thrustcurve.org.
Looking at the history of Estes’ Saturn V kits, 250 ft isn’t far off of what you can reasonably expect for this design. Estes’ site indicates that the 1988 1/100 Saturn V flew on a D12-3 and only went 100 ft (although the site words it to make it sound like that’s a lot). The 50th Anniversary reissue of the 1969 1/100 kit is listed as being capable of 350 ft on the E30-4 composite motors they were offering for a while. Those motors are out of production under the Estes banner now but I believe they were just rebranded AeroTechs.
The 1/200 ready-to-fly model does about 200 ft on a C6-3.
With such low altitudes attainable, I don’t think you’ll have to worry too much about stability so long as it’s not completely backwards. It’s not going to be blown off by a gust of wind and go into the next state, so this:
won’t be as much of a problem as it would be with a very high-performance model.
Regarding the colors available, I personally don’t find it all that important in and of itself. But having different propellants available allows Aerotech, Cesaroni, etc. to offer a wider selection of motors. I don’t think your average modeler cares all that much about whether they’re flying with a violet flame or a thick BlackJack smoke trail, but I think they DO care whether they’re getting, just for example, an F44 with a short burn time that’s towards the bottom of the F impulse class vs an F44 with a really long burn time that’s closer to the top. Or they might prefer an F44 with the much lower cost per flight of a reloadable motor system, maybe they want the convenience of a single-use F44.
Having different propellant formulations that produce different colors is just a useful shorthand to tell the difference between various F44s (or any motor designation you can think of) that have different thrust curves and flight economics.
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