Moving up to a D motor.

[Senior Space Cadet]

I'd made the decision that the D engine was probably as far as I'd go, in model rocketry. Any more powerful and you have to pay an exorbitant extra shipping fee, on top of the cost of a new rocket. Just too expensive for my blood. I've already got some expensive hobbies and thinking about buying a used Mercedes or something.
I just place an order for parts for a new D powered rocket. It's going to be big or, at least, fat. I suppose the sensible thing would have been to go with a 33mm body tube, but I went with 66mm. Mostly, I suppose, because Estes makes a 66mm nose cone I wanted to use. I suppose that's like buying a car because you like the spoiler, but that's what I did. I also ordered some ready made plywood fins from Apogee, and some pre-slotted tubes, so I know the fins will be on straight.
The only real question is length. I ordered enough tubes and couplers that I could make a very big rocket, if I wanted to. This is where, I hope, Open Rocket comes in. I just tried to download it. Haven't checked if it is on my computer and I can access it. As I've said, I'm not very tech savvy. And, no, that doesn't mean I hate computers, I love my computer, it just means I'm not very good with it. When I was going to Ohio State, I signed up for a computer class. This is when computers used punch cards and were about the size of a large refrigerator, as I remember it. I ended up dropping that class. Probably one of the big mistakes of my life.

 

[OverTheTop]

D motors can launch decent size rockets. Enjoy! I tend to fly D motors frequently when I want a nice easy flight. After that I don't fly much below L. You will find where you enjoy the hobby and what you want to spend per flight personally. For me L motors are the sweet spot. To each their own.

As for working through OR, just take your time. I think people on the forum might be able to help you also. Not me unfortunately, as I use RockSim.

 

[Spitfire222]

Have you actually launched a rocket yet?

 

[Antares JS]

Any more powerful and you have to pay an exorbitant extra shipping fee, on top of the cost of a new rocket.

For Estes BP motors, yes, but there are composite motors from E-J that are specially made to avoid hazmat shipping, just so you know. You can also see if a local hobby shop carries the big Estes motors. I usually get my E12's from Hobby Lobby to avoid paying to ship them.

I've linked Aerotech's "Master Motor Matrix" below. There's one column labeled "USPS Mailable." Any motor labeled "Yes" in this column does not require a hazmat shipping fee. They start at D, and the largest one that is USPS mailable is the J520W.

It's also worth noting that a hazmat shipping fee is charged per box. Most of us save on hazmat shipping by buying a lot of motors at once. $35 to ship doesn't seem so bad if you're buying hundreds of dollars worth of motors anyway. Buyrocketmotors.com also waives the hazmat shipping fee if you spend $399.

I'm not sure if this changes anything for you, but I don't want you to miss out over hazmat shipping if going bigger is something you want to do.

https://www.aerotech-rocketry.com/u...897bb_AeroTech Master Motor Matrix 7-5-18.pdf

 

[dhbarr]

Specifically, the AT-29/40-120 case is a gateway drug, will take you right up to the FAR101 Model Rocket limits.

But re: your original query, the venerable Estes d12-3 can lift a pretty substantial bird, about 350g / 12oz dry.

 

[Funkworks]

If you get a used Merc and plan to keep it for years, you also need a maintenance budget that could easily be the same amount as what you pay for the car. Tires , brakes , fluids , suspension , everything wears out as with any other car. And some things can only be done at the dealer , so just be ready. The ride on a smooth road however, is just about as comfortable as a living room recliner.

I don't launch very often, so I've managed by having minimal motor expenses and stretching out my rocket builds over months.

 

[neil_w]

As far as 24mm single-use motors go, the Aerotech E15W, E20W, E30, and F44W all ship hazmat-free. At 29mm there are several single-use F motors in the Enerjet line that ship hazmat-free (including the F67 which gives tremendous bang for the buck.) All these motors are just about as easy to use as Estes BP motors, they'll just send your rockets up quite a bit faster and higher.

If you make the move to reloadables then you have a huge range of options.

So don't place any artificial limits on yourself yet.

 

[lakeroadster]

Have you actually launched a rocket yet?

That's helpful...

 

[jrap330]

I'd made the decision that the D engine was probably as far as I'd go, in model rocketry. Any more powerful and you have to pay an exorbitant extra shipping fee, on top of the cost of a new rocket. Just too expensive for my blood. I've already got some expensive hobbies and thinking about buying a used Mercedes or something.
I just place an order for parts for a new D powered rocket. It's going to be big or, at least, fat. I suppose the sensible thing would have been to go with a 33mm body tube, but I went with 66mm. Mostly, I suppose, because Estes makes a 66mm nose cone I wanted to use. I suppose that's like buying a car because you like the spoiler, but that's what I did. I also ordered some ready made plywood fins from Apogee, and some pre-slotted tubes, so I know the fins will be on straight.
The only real question is length. I ordered enough tubes and couplers that I could make a very big rocket, if I wanted to. This is where, I hope, Open Rocket comes in. I just tried to download it. Haven't checked if it is on my computer and I can access it. As I've said, I'm not very tech savvy. And, no, that doesn't mean I hate computers, I love my computer, it just means I'm not very good with it. When I was going to Ohio State, I signed up for a computer class. This is when computers used punch cards and were about the size of a large refrigerator, as I remember it. I ended up dropping that class. Probably one of the big mistakes of my life.

If your going "D" and that is my favorite engine...buy a kit first. You might make it too big and heavy. As for open rocket...find the thread from a few weeks ago about install issues. There was an additional file I downloaded that allowed Windows to "open" or "run":the program.

 

[Senior Space Cadet]

I got all the main body parts in.
Plywood fins seem pretty heavy, but I'm hoping to make them airfoil shape, which should reduce weight.
I didn't order and D motors because I already have a bunch of smaller motors and no clubs are launching around here. But I think I'm going to have to order at least one package so I can be sure everything fits.
One reason I went with such a big, fat rocket is, I have some serious eye problems. Even with glasses, my eyes aren't 20/20. I'd like to be able to watch the rocket go up.
I'm going to try and use Open Rocket for this build. I'm positive I can make it fly OK without out it, but if I can optimize body length and nose cone weight, I'll get better performance.
Attached is a photo of what the rocket would look like if I were to use two whole body tubes. I could end up using one, or something in between, it depends on what Open Rocket has to say.

 

[jrap330]

Big Bertha nose cone. For such a large rocket, bigger fins would look better and maybe necessary for its size. Eyesight, I see 20/40 w/ glasses which is why I lose most rockets on the way up.

 

[Senior Space Cadet]

If you get a used Merc and plan to keep it for years, you also need a maintenance budget that could easily be the same amount as what you pay for the car. Tires , brakes , fluids , suspension , everything wears out as with any other car. And some things can only be done at the dealer , so just be ready. The ride on a smooth road however, is just about as comfortable as a living room recliner.

I don't launch very often, so I've managed by having minimal motor expenses and stretching out my rocket builds over months.

The repair costs are definitely something I'm looking at. But a really nice, low mileage, used Mercedes for $16,000, is pretty tempting. Never thought I'd be able to own one in this lifetime. It's a matter of priorities. What is higher on my priority list?

 

[Senior Space Cadet]

Big Bertha nose cone. For such a large rocket, bigger fins would look better and maybe necessary for its size. Eyesight, I see 20/40 w/ glasses which is why I lose most rockets on the way up.

I realize that the sensible thing would have been to just order a Big Bertha, but I didn't want to be constrained by a kit.
I noticed the fins looked a little small on the rocket, but they stick out farther than the tube diameter and were made to fit the pre-slotted body tube.
I'll see if they look better if I shorten the rocket.
What I'm more worried about now is the NAR limit on rocket weight. Seems like it would be pretty easy to surpass.
Now I need to buy a good scale. One more expense.

 

[Senior Space Cadet]

For Estes BP motors, yes, but there are composite motors from E-J that are specially made to avoid hazmat shipping, just so you know. You can also see if a local hobby shop carries the big Estes motors. I usually get my E12's from Hobby Lobby to avoid paying to ship them.

I've linked Aerotech's "Master Motor Matrix" below. There's one column labeled "USPS Mailable." Any motor labeled "Yes" in this column does not require a hazmat shipping fee. They start at D, and the largest one that is USPS mailable is the J520W.

It's also worth noting that a hazmat shipping fee is charged per box. Most of us save on hazmat shipping by buying a lot of motors at once. $35 to ship doesn't seem so bad if you're buying hundreds of dollars worth of motors anyway. Buyrocketmotors.com also waives the hazmat shipping fee if you spend $399.

I'm not sure if this changes anything for you, but I don't want you to miss out over hazmat shipping if going bigger is something you want to do.

https://www.aerotech-rocketry.com/u...897bb_AeroTech Master Motor Matrix 7-5-18.pdf

I've been sticking with Estes motors because I know the name from back in Junior High, when Lincoln was president, and they are so close to me I get my stuff in a couple days, but I'm seeing that may not be what you more experienced guys use. You aren't the first one to recommend Aerotech. I'll look into them.

 

[OverTheTop]

I fly plenty of the Estes BP motors in D size (I think I even have some E motors in the cupboard). As the motors get bigger they switch to APCP (ammonium perchlorate composite propellant) because the energy is about twice as much for the same volume taken up. BP motors are fun, but as you go bigger you need to keep the specific impulse (Isp) high by using the fancier chemistry of APCP. This keeps the size of the motors down and has some other advantages as well.

Specific impulse is essentially the fuel economy figure for the motor. The higher the number the better the fuel economy (ie less fuel to generate the same amount of energy).

 

[Senior Space Cadet]

Never mind about me being worried about the weight issue. NAR safety code says not to launch rockets over 53 ounces, I though it was 5.3. As I said, I can't see very well. I often have to take my glasses off and stick my face up to the screen.
I just tried the fins with one (18") body tube and they look much better. I like the look better than the Big Bertha fins and, in the long run, it will end up being cheaper. I can probably make at least two, and maybe three, rockets for the price of a Big Bertha kit.

 

[Antares JS]

I've been sticking with Estes motors because I know the name from back in Junior High, when Lincoln was president, and they are so close to me I get my stuff in a couple days, but I'm seeing that may not be what you more experienced guys use. You aren't the first one to recommend Aerotech. I'll look into them.

Don't get me wrong, Estes is great! I have a big stash of both Estes motors and Aerotech motors. It's just that Estes only makes BP motors and those can only be made so big without them being prone to problems such as cracked propellant grains causing CATOs, and as you have run into, any BP motor bigger than the D12 has a propellant weight large enough to require hazmat shipping.

Aerotech makes composite motors, which can be made much bigger without running into those cracking issues because composite propellant has a more rubbery consistency that doesn't crack so easily. As OverTheTop mentioned, composite propellant also produces more power for the same weight, so Aerotech can get a more powerful motor into the same propellant weight as an Estes motor and ship them without paying hazmat shipping.

 

[Charles_McG]

The Estes Quinstar is a fun kit that keeps Ds close to the ground, loud, and smokey. A very enjoyable way to turn money into smoke.

How big is your flying field?

 

[dr wogz]

Senior, don't pass up kits quite so fast. They are a great way to get the components you want & need..

Remember, they all look the same upside down! (They all have the same / similar parts inside..) A 'Mean Machine' is a good source for tubes.

 

[Senior Space Cadet]

My battle plan is to spend several days watching Open Rocket tutorials and learning my way around the program.
My hope is that I'll be able to come up with the optimum body length for the nose cone and fins I've chosen If it ends up being the same length as a Big Bertha, I'm going to be disappointed.

 

[Senior Space Cadet]

If you get a used Merc and plan to keep it for years, you also need a maintenance budget that could easily be the same amount as what you pay for the car. Tires , brakes , fluids , suspension , everything wears out as with any other car. And some things can only be done at the dealer , so just be ready. The ride on a smooth road however, is just about as comfortable as a living room recliner.

I don't launch very often, so I've managed by having minimal motor expenses and stretching out my rocket builds over months.

I'd settle for this instead.
https://www.msn.com/en-us/autos/ent...s-father-s-day-gift/ar-BB15C3dl?ocid=msedgdhp

 

[ThirstyBarbarian]

I have bad vision too, so I like large size rockets that are easy to see, and I don’t fly them as high as many people do. If you like to keep your rockets to a lower altitude so you can watch the whole flight, see the ejection, watch the chute come out, and keep your eye on it all the way to the ground, try fatter rockets. The drag on a wide diameter rocket helps keep it low and in sight.

So, for example, an Estes Big Daddy kit is 3” in diameter and can be flown on a D12, and it will stay lower than a 2” diameter kit of the same weight. If you like them a bit taller, then Estes kits made from 2.6” BT-80 tube are great. I used to love flying my Estes Maxi Alpha 3 on D motors. That kit is out of production now, but something in that size range is about right, and it sounds like that’s what you are building, so you are on the right track.

Regarding hazmat shipping, there are lots of more powerful composite motors that do not require hazmat shipping, including plenty of single-use motors that don’t require hardware, and don’t require you to build the motor. An Aerotech E20, E15, or E30 will fit in an Estes D motor mount. I think even an F44 will fit in that mount, if it is the same length as the others. They will definitely all fit In an Estes E mount. Those motors do not require Hazmat shipping, but each motor is probably more expensive than an Estes E. If the price is acceptable, that would open up options for even larger rockets.

You can kind of have it both ways too if you like. You have an extra tube, but if you use it, maybe it will make the rocket too heavy for an Estes D. I used to like to have a removable payload tube for my Maxi Alpha 3. Do you have a coupler? You could buy or cut a bulkhead for your coupler and mount an eyebolt in the coupler for your recovery system. That’s all you need for a removable payload section. You could fly the short version of the rocket on Estes D motors. But if you wanted to try an E20, for example, You add in the payload tube, and fly it in the extended configuration. It would be easy to make something similar for a Big Daddy.

Lots of possibilities! I found that as I got more into rocketry, I loved flying some of the largest sized rockets on the field, but not super high. That F44 motor I mentioned would be great for low altitude flights on large 3” rockets. If you want even larger rockets, the 29mm F20, F23, F27, F42, and F67 all ship without hazmat, and allow for even bigger rockets. That F67 can lift a big 4” diameter rocket, and still keep the flight pretty low.

Good luck, my fellow low-vision rocketeer!

 

[MALBAR 70]

Just keep in mind that if you do move up to composites, unless you are flying with a club, you will have to upgrade your launch equipment as well. A 12volt launch system and possibly a jaw stand with a 10/10 rail launch pad will be much sturdier than a rod.

 

[ThirstyBarbarian]

Just keep in mind that if you do move up to composites, unless you are flying with a club, you will have to upgrade your launch equipment as well. A 12volt launch system and possibly a jaw stand with a 10/10 rail launch pad will be much sturdier than a rod.

True, most (not all) igniters for composite motors require 12 volts, or at least 9 with plenty of current.

And once you start flying rockets over a pound, or pound and a half, and using F motors, you should move up to a rail. A rocket on an E20 and under a pound can fly off a 1/4” rod ok.

 

[neil_w]

You s

And once you start flying rockets over a pound, or pound and a half, and using F motors, you should move up to a rail. A rocket on an E20 and under a pound can fly off a 1/4” rod ok.

A rocket on an E and under 8 oz or so can fly just fine off a 3/16" rod.

 

[jrap330]

Never mind about me being worried about the weight issue. NAR safety code says not to launch rockets over 53 ounces, I though it was 5.3. As I said, I can't see very well. I often have to take my glasses off and stick my face up to the screen.
I just tried the fins with one (18") body tube and they look much better. I like the look better than the Big Bertha fins and, in the long run, it will end up being cheaper. I can probably make at least two, and maybe three, rockets for the price of a Big Bertha kit.

I did not mean Big Bertha Fins...I meant looks like a Big Bertha nose cone (yes/no?) and maybe the fins are too small. I don't like the Big Bertha fins...since they stick way beyond the aft end of body tube..they break..at least on my BB kit..I broke 2 fins.

 

[ThirstyBarbarian]

You s

A rocket on an E and under 8 oz or so can fly just fine off a 3/16" rod.

That’s definitely true. But my impression is he’s leaning toward larger size rockets as he goes up in motor size. So I’m guessing if he goes to an E motor, he would be using it in a rocket that is bigger than 8 oz. An 8 oz rocket isn’t very big in physical size, and on an E motor, it will go pretty high — not a great combo if your vision isn’t so good.

 

[AfterBurners]

BP motors can add as well. Not sure what the cost of 3 pack is, but it can add up. Another option is to go with a 18mm RMS? Not even sure you can get 18mm anymore?

 

[Antares JS]

Another option is to go with a 18mm RMS? Not even sure you can get 18mm anymore?

You can. Just picked up the 18/20 case from Hobbylinc during a sale. They were out of stock on the reloads but eRockets has them.

 

[AfterBurners]

You can. Just picked up the 18/20 case from Hobbylinc during a sale. They were out of stock on the reloads but eRockets has them.

Actually I think?? The reloads are about as much as a 3 pack or 2 pack of D/E BP motors? Not sure haven't flown BP in awhile? Another thing thats good about the 18mm RMS you can fly C motors in the same rocket as well?