Mike, y,our videos are very professional. This is excellent!

@MikesInventions

Ай бұрын

Thanks Klaus! Comments like yours keep me motivated to create content. If you're interested in flying, check out my newest, 121.Mike. Thanks for watching!

Thank you Mike. I've been waiting for more rocket content. I really apricate your well explained short video, it really helps me on beening confident even with simple eqausions.

@MikesInventions

4 жыл бұрын

Swiss-Dynamics you’re welcome! This was done with you in mind. I’ve got another one coming soon about designing and building from scratch.

@swiss-dynamics5877

4 жыл бұрын

@@MikesInventions I am really honored. Thank you again for your work it keeps me focused on rocketry and the work that has to be made and I am just really excited about the new video you're planning since this is also such a good topic that almost nobody covers. Thanks again.

Very good explanation.

Thanks Mike, aerotech is a fun field of study.

Thank you a lot!

3:37 That's some epic content

I like your arrow explanation. Not to contradict your excellent info, but in my experience unfletched arrows (those without fins) can fly laser straight. Their secret is a heavy point; a 13 gram arrow shaft might have a 13 gram point at the very tip of it's 700mm length. It is very stable until acted upon by an outside force like strong winds or glancing off a tree branch. That's where an arrows fletching really helps, bringing the nose back in line quickly and not letting the arrow rotate much, keeping it on target. My unfletched arrows and my compound bow are tuned well enough to allow me to strike a target 50 meters away 100% of the time with an unfletched arrow. Any competent archer could do the same. In fact, bare shaft tuning as it's called, is a process every serious archer performs.

@MikesInventions

10 ай бұрын

Hey there! You’re right about unfletched arrows being able to fly just fine. The heavy tip moves the cg forward without moving the cp forward. This arrangement makes it stable. I’ve got a video where I built an unfletched rocket. Check it out! m.kzread.info/dash/bejne/e4Z92pOGZZi_fqg.html

FYI: I recognize your rocket prop. It is a phoenix missies used on F14 tomcat!!!!

@MikesInventions

Жыл бұрын

Sure is! A tad smaller of course. Thanks for watching.

Great video! Any reason not to move the CG forward a couple of inches on your Phoenix demo rocket to increase it's stability to 2 calibers? I am building a clone of that Estes rocket right now and would like to make it more stable.

Super

This guy is like Sheldon from big band theory

Thanks you mike,but can you make tutorial how to find all of that centars,and centar of mass,where it needs to be and and centar if thrust i think i am not sure. I want to make my diy sugar powred rocket one time and add camera in it to see if can reach almost earth 2th atmosphere. And it would be nice if you explain velocity,distance and speed because you are best at explain things

can you make a video about how weird you can go with a rocket outer design without going nowhere.?

A most excellent video it may be aged but I used to have that very model launched it many times unfortunately it’s not available anymore hasn’t been for years now and 2022 I can’t even find plans for, sadly

@MikesInventions

2 жыл бұрын

Thanks Keith! I love my Phoenix.

Cool Video man... Could you tell me something about the Center of Thrust? Im about to build a small DIY rocket, and I am wondering... If the CG is above the center of thrust.... Why most of the rockets are still stable? Is it all about the fins? WHat If Im not using Fins? (It would be a Falcon9 type rocket).

@MikesInventions

4 жыл бұрын

Hey Pandicus. Having the thrust above the cg, like a Robert Goddard rocket, actually does not make the rocket go straight up. It's not like a pendulum, it just makes the rocket continue to go where it's pointing. His rocket was stable anyway. Putting engines at the front is also really hard for all sorts of reasons. See if you can come up with a few... ( I can think of 4 as I type this. ) The center of thrust needs to point through the center of gravity. When it doesn't the rocket will rotate because of a torque, right? You can make a finless rocket, you just have to keep the CG ahead of the CP. This is what happens with those cheap bottle rockets that have the long stick. You'll basically be using your body tube as the stick, but because it's the same cross section all over, you'll have to add weight to the nose to move the CG forward. Your heavy engine in the back will need to be countered by a larger weight on the front. This will give you an authentic finless look. Real rockets don't need fins because they're steered by gimballed engines. They turn the engines to turn the rocket, then straighten them out when they're pointing where they want to go. Like driving a car. Model rockets don't have that ability (they could...), so we put big fins on them to keep them stable. Now your finless rocket will be free to spin, but that's really no big deal. Hope that helps. Neat project, good luck!

@pandicus1412

4 жыл бұрын

@@MikesInventions Thanks very much bro... that makes sense. :) Im gonna make few tests based on your advices. ;) ;) (Went for sub)

Thank you so much! This video is so helpful to understand the terms. But i have a question, me and my team are going to join a rocket competition so we use 'openrocket' application to calculate this kind of values. Our rocket's beginning stability is okay but at the apogee point stability gets higher because of the decreasing of the fuel (we do not want that). What should we do about this problem? What do you suggest us?

@MikesInventions

3 жыл бұрын

Hi! I’ve never used any program other than my rocket designer excel sheet. At apogee there is no stability because the rocket has stopped moving fast enough. That’s why it’s able to turn around to f the recovery device hasn’t fired. There’s really no simple way to avoid the extra stability issue. What is your rocket going to do at apogee?

@elifecekeskin5644

3 жыл бұрын

@@MikesInventions Thank you so much for answering me. Our rocket must release the payload at the apogee and it must make safe landing. We had some problems about rocket’s stability but as you said there is no simple way to solve it. But we kept try to approach the CP and CG in order to decrease the stability and we succeed (thanks to your video)

To deal with this subject adequately, you need to discuss why an elongated object (rocket or arrow) tends to turn sideways to the direction of travel regardless of where the cofg is. An arrow fired from a bow will rotate sideways if the fleches (fins) are removedeven though the tip is weighted. Ask any archer.

@MikesInventions

Жыл бұрын

Hi Kenneth. I guess I don’t understand what you mean about things tending to turning sideways. What information was missing or unclear? I’ll see what I can do.

What's the minimum TWR for a rocket to go up 100 meters, 1000 meters ??? Thanks

Could you more clarify on the dimensions you mentioned about the distance between cg and cp for stable flight

@MikesInventions

3 жыл бұрын

Hey Dinesh! The CG needs to lead the CP by a distance of 1-2 body tube diameters. Any more and you have excessive stability, which really just equals excessive weight either in the nose or fins.

Great explanation. What happens when the cp is in front of the cg? does it just flip?

@MikesInventions

2 күн бұрын

Yes, exactly

thank you im in grade 9 and this video came in clutch for my project thank you also do you know how to make a successful parachute

@MikesInventions

3 жыл бұрын

Hey! Good to hear it helped. Parachutes are easy. Thin plastic like from trash or grocery bags and some string like I waxed floss or upholstery thread works for the lines. Knot the ends and tape it to the plastic. Use at least 4 lines. No need to be round either. Then use a rubber band as a shock cord and you’ve got an easy cheap parachute.

@aksh_x_

3 жыл бұрын

@@MikesInventions I did some research about parachutes, it takes heck of a calculations to get the desired parachute for the rocket to descend it at the desired speed. Would be great if you make a video explaining the equations and solving some numerical!

How can I determine my CP? I have a 3d printed rocket with a larger cone than the body, like Falcon 9 rocket for its satellite payload. I assume that automatically moves my CP upwards as its no longer a stick with a motor. If I can not move the CP, largest fins I can put on it, is it ok to move the CP upwards?

@MikesInventions

Жыл бұрын

Hey! You’re right about your CP moving forward because of the fatter fairing. I have a video in my rocket science playlist that shows how you can find the CP. the only way you can move the CP is by changing the geometry of the rocket. As a last resort, you can add weight to your larger nose maybe to move the CG forward. Keep the CP behind the CG by 1-3 body tube widths and you’re fine. Thanks for watching!

@GenCodeFPV

Жыл бұрын

@@MikesInventions Mike it now no longer flips over and over like it used to, but it did do one gentle corkscrew roll and continued upwards. Any ideas what should change? I used a D motor, I think maybe a B would be better and make the body longer? kzread.info/dash/bejne/gGR6spV6YLvQgbw.html

@MikesInventions

Жыл бұрын

@@GenCodeFPV so I’m a large portion of your views now. That maneuver is a combination of pitch and roll like a barrel roll. That could mean that the fins are asymmetrical slightly, but it’s possible the motor is slightly misaligned or a gust of wind combined with a vibrating launch rod. With a launch like that, it’s probably safe to try launching again and see if it does it again. If so, it’s probably a slight fin issue. You’d probably not get the same combination of other factors a second time.

@GenCodeFPV

Жыл бұрын

@@MikesInventions this was 3d printed so I think motor align is ok, I do have fins at 2 locations, one bottom of the body and the motor section, I may have had the slightly off. My recovery failed to pop open so I’ll fix that check fins and try again, thanks for all the help

So now, how do we find the center of pressure?

@dontbelieveeverythingblindly

3 жыл бұрын

What's center of pressure...can you explain please !

@bargainbin22

3 жыл бұрын

@@dontbelieveeverythingblindly It seems to be a point kind of like the center of gravity that is a point that keeps the rocket moving in a straight line upwards. It stops the rocket from going crazy. In my opinion it is extra drag on the tail of the rocket. Fins help with it or a longer stick or even extra weight.

@MikesInventions

3 жыл бұрын

Hey there guys! I have a couple of videos on CP. check them out! kzread.info/head/PLH-oe77sgzLISpAfKmbK_EQjD6NsiKZ5w

@bargainbin22

3 жыл бұрын

@@MikesInventions Mike I have watched them and several more and none explain how to find the CP some came close but none pin point it without long algebra.

@MikesInventions

3 жыл бұрын

@@bargainbin22 Yeah, the algebra can be tough. I find it quick, but there is another way if you want to do it experimentally. You need to cut out a projection of your rocket. It needs to be made of a homogeneous material, like cardstock or something. Then you hang this from a string or lay across it a sharp edge and find where it balances. That's the CP. It works because CP is the average of all the projected areas, and a material will balance at it's CG, but since the "rocket" is homogeneous, it's CG happens to be at its CP as well.

This all makes sense, but if you didn’t want to do the math, can’t you just put a massive amount of weight in the nose? Then it will be stable for sure

@MikesInventions

4 жыл бұрын

Hey there! You could put a "massive" amount of weight in the nose, but it might be heavier than needed, thus not fly as high. You can avoid math by checking stability with the twirl test, as shown in this video: kzread.info/dash/bejne/Z4eCrbmNd6rIfM4.html My website also has an excel file that you can design rockets with, so you don't have to do all the balancing math. Thanks for watching!