Newbie, first rocket

peeler5150

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Hello, all. New kid to rockets here. Previous background was heavy in electronics but the parts got too small for me to read. I bought my first rocket kit but haven't received it yet. A Sky Metra, 2 stage with payload, BT-50 size. I plan to avoid wadding and use a baffle with a cooling mesh.

I bought Estes engines. I looked at Q-Jet products but don't see a benefit in performance over Estes engines in the A to D sizes. Q-Jets run almost twice the price. Am I missing something?

Some things I read suggest multiple coats of primer to get a smooth surface. Coming from previous experience in radio control planes I am familiar with light weight balsa filler to fill in those irregular surfaces. Has anybody used this for rockets? Hobby Lite and such.
 

smstachwick

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Hello, all. New kid to rockets here. Previous background was heavy in electronics but the parts got too small for me to read. I bought my first rocket kit but haven't received it yet. A Sky Metra, 2 stage with payload, BT-50 size. I plan to avoid wadding and use a baffle with a cooling mesh.

I bought Estes engines. I looked at Q-Jet products but don't see a benefit in performance over Estes engines in the A to D sizes. Q-Jets run almost twice the price. Am I missing something?

Some things I read suggest multiple coats of primer to get a smooth surface. Coming from previous experience in radio control planes I am familiar with light weight balsa filler to fill in those irregular surfaces. Has anybody used this for rockets? Hobby Lite and such.
Estes motors are black powder end burners, and they’re well-known for affordability, reliability, and ubiquity. Q-Jets are a relatively new product line that brings advanced C-grain or core-burning composite propellants (I forget which) to a larger consumer base than could be accomplished by the older Aerotech lines.

Although end-burning black powder Estes motors have good thrust in the lower impulse classes, they tend to be a bit anemic as you get into C-F territory. Q-Jet motors in that range have higher thrust than their black powder Estes counterparts. Their 18mm C12 motor is comparable to a 24mm Estes C11, and is well-suited to heavy rockets. There is also a C18 available and 18mm Ds. You can’t create a black powder D motor with the standard 18x70mm casing, but it’s very doable with composites. Ditto with E motors in a 24x70mm casing.

There are a few issues with Q-Jets though. The ejection charge cap can get caught on the forward end of Estes motor hooks and get stuck in a mount, so you may have to yank it to get it out. There are also some known issues with the nozzle and casings deteriorating prior to flight, and you have to destroy such motors by firing them stuck in the ground like a Roman candle. Estes motors can simply be soaked in water until the paper casing comes unwound and the remnants can be thrown away, it’s safer that way. And on a more personal note, Estes motors smell better when they’re burned. 🙂

It may also be harder to get Q-Jet igniters in all the way, too. The channel is deep and narrow, the motor must be ignited from the top end for the delay to work properly. For this reason they cannot be staged like black powder motors. You have to use electronics to trigger upper stage ignition.

The Q-Jet As also have less average thrust than the Estes As (which may actually work to your advantage, depending on your launch objectives) and there is no 1/2A option with Q-Jets. They may also be harder to find at hobby shops, I only know of one in my town that carries them.

If you’re looking to get into higher power ranges like the Econojet/Enerjet lines or any other kinds of composites like reloadables, having experience with these motors may be helpful. Maybe consider trying them at some point down the line.

That’s all I can think of, at any rate.
 
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neil_w

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Above post covers the Estes/Q-jet question pretty well, but I'll add one more thing: they're different. Different thrust curve, different noise, different smoke. Variety is nice.

Regarding balsa filling: there are many (many!) ways to do it. Primer (even high-build) is generally not sufficient to fill balsa. The two most common techniques are either to use some sort of filler (e.g. Carpenter's Wood Filler) or some sort of paper. Nowadays I paper almost all my fins using Avery label paper.

If you're just getting started I strongly recommend reading through some builds on Chris Michielssen's blog: https://modelrocketbuilding.blogspot.com/. He covers just about every imaginable aspect of building low-powered rockets. He is @hcmbanjo on this forum.

Oh, and one more thing: welcome to the forum! Please post pictures. :)
 

Sandy H.

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One of the club member I flew with for years made 'the best' looking rockets. For fact, I have seen people here on the forum that have made best-er looking rockets, but all of his builds were worthy of public display.

His background was RC and he often used Hobby Lite for balsa cones. I think for fins, he tended to do something different, though, as the fins flex a bit in normal flight and often on landing and/or transport and I thought he said Hobby Lite sometimes cracked or popped out.

He and I haven't been at the same launch for years (various reasons, none bad), but I hope I see him at a launch soon and if so, I'll ask for more details!

But, as Neil said above, there are tons of A+++ builds on this forum and at places referenced on the forum. I'm no help, because I don't even fill tube spirals. . .my best ever build would be a B- or C+, depending on how many of the judges hadn't passed out when viewing my work. :)

Sandy.
 

peeler5150

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Estes motors are black powder end burners, and they’re well-known for affordability, reliability, and ubiquity. Q-Jets are a relatively new product line that brings advanced C-grain or core-burning composite propellants (I forget which) to a larger consumer base than could be accomplished by the older Aerotech lines.

Although end-burning black powder Estes motors have good thrust in the lower impulse classes, they tend to be a bit anemic as you get into C-F territory. Q-Jet motors in that range have higher thrust than their black powder Estes counterparts. Their 18mm C12 motor is comparable to a 24mm Estes C11, and is well-suited to heavy rockets. There is also a C18 available and 18mm Ds. You can’t create a black powder D motor with the standard 18x70mm casing, but it’s very doable with composites. Ditto with E motors in a 24x70mm casing.

There are a few issues with Q-Jets though. The ejection charge cap can get caught on the forward end of Estes motor hooks and get stuck in a mount, so you may have to yank it to get it out. There are also some known issues with the nozzle and casings deteriorating prior to flight, and you have to destroy such motors by firing them stuck in the ground like a Roman candle. Estes motors can simply be soaked in water until the paper casing comes unwound and the remnants can be thrown away, it’s safer that way. And on a more personal note, Estes motors smell better when they’re burned. 🙂

It may also be harder to get Q-Jet igniters in all the way, too. The channel is deep and narrow, the motor must be ignited from the top end for the delay to work properly. For this reason they cannot be staged like black powder motors. You have to use electronics to trigger upper stage ignition.

The Q-Jet As also have less average thrust than the Estes As (which may actually work to your advantage, depending on your launch objectives) and there is no 1/2A option with Q-Jets. They may also be harder to find at hobby shops, I only know of one in my town that carries them.

If you’re looking to get into higher power ranges like the Econojet/Enerjet lines or any other kinds of composites like reloadables, having experience with these motors may be helpful. Maybe consider trying them at some point down the line.

That’s all I can think of, at any rate.
 

peeler5150

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Granted Ammonium Perchlorate (composite rocket engines) packs more bang in a smaller space compared to Estes black powder types. The specs for an A3-4T Estes read much the same as Q-Jet's A3-4T. The Estes part runs about $3.00 each versus $5.25 for the Q-Jet.
Larger engines are a very different story.
 
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peeler5150

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Estes motors are black powder end burners, and they’re well-known for affordability, reliability, and ubiquity. Q-Jets are a relatively new product line that brings advanced C-grain or core-burning composite propellants (I forget which) to a larger consumer base than could be accomplished by the older Aerotech lines.

Although end-burning black powder Estes motors have good thrust in the lower impulse classes, they tend to be a bit anemic as you get into C-F territory. Q-Jet motors in that range have higher thrust than their black powder Estes counterparts. Their 18mm C12 motor is comparable to a 24mm Estes C11, and is well-suited to heavy rockets. There is also a C18 available and 18mm Ds. You can’t create a black powder D motor with the standard 18x70mm casing, but it’s very doable with composites. Ditto with E motors in a 24x70mm casing.

There are a few issues with Q-Jets though. The ejection charge cap can get caught on the forward end of Estes motor hooks and get stuck in a mount, so you may have to yank it to get it out. There are also some known issues with the nozzle and casings deteriorating prior to flight, and you have to destroy such motors by firing them stuck in the ground like a Roman candle. Estes motors can simply be soaked in water until the paper casing comes unwound and the remnants can be thrown away, it’s safer that way. And on a more personal note, Estes motors smell better when they’re burned. 🙂

It may also be harder to get Q-Jet igniters in all the way, too. The channel is deep and narrow, the motor must be ignited from the top end for the delay to work properly. For this reason they cannot be staged like black powder motors. You have to use electronics to trigger upper stage ignition.

The Q-Jet As also have less average thrust than the Estes As (which may actually work to your advantage, depending on your launch objectives) and there is no 1/2A option with Q-Jets. They may also be harder to find at hobby shops, I only know of one in my town that carries them.

If you’re looking to get into higher power ranges like the Econojet/Enerjet lines or any other kinds of composites like reloadables, having experience with these motors may be helpful. Maybe consider trying them at some point down the line.

That’s all I can think of, at any rate.
 

TigerHawk

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The Estes part runs about $3.00 each versus $5.25 for the Q-Jet.
Shop around for the best prices as you can do better than that price there.


Even cheaper in bulk,
 

smstachwick

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Granted Ammonium Perchlorate (composite rocket engines) packs more bang in a smaller space compared to Estes black powder types. The specs for an A3-4T Estes read much the same as Q-Jet's A3-4T. The Estes part runs about $3.00 each versus $5.25 for the Q-Jet.
Larger engines are a very different story.
There are a few differences though. Thrust curve is one.

Estes A3:


31E0F820-7087-4524-88E0-08574E7C59A6.png

Q-Jet A3:

D7E23496-4876-48C7-8CAF-7D6B7BF25379.png

And just because it interested me, the Estes A10

89AB590E-8D42-4DC4-8AA8-FE119ACB6609.png

and the Estes A8:

3A638226-2712-4F11-AE3F-39A0E02C5E47.png

Now, I don’t think the difference in any of these is decisive enough to generate recommendations on which ones to use in which rockets, but it’s kind of interesting to see nonetheless.

Also of interest is the apparent misnaming of some of the Estes motors. The A10 is actually more like an A2, with the designation advertising its higher maximum thrust. The Estes A8 is a carryover from the early days when everything was advertised in pounds of average thrust instead of Newtons. It was the A .8 then. In Newtons it’s more like an A3 (so my mistake then, the average thrusts are actually pretty comparable).

Diameter will also influence selection. If they’re too big you’re out of luck, if they’re too small you’re going to have to mess around with adapters.

Is all that worth an extra $2 a pop for Q-Jets? Probably not. But I’m sure people will still buy them anyway for reasons that aren’t dictated by this sort of logic.
 
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The main reason why I try the composite motors is for the unique exhaust and the initial thrust off the rod. Mainly, W produces white flame and T produces blue flash. The BP motors are more slow burning and composite faster off the rod. Faster means it flies straighter and less likely to arc over if the rocket is heavy or less aerodynamic.
 

teepot

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For filling grain I tried Hobby Lite a few times. Switched to Elmer's color change filler. That became unobtainium. I tried and will continue to us GoodFilla wood grain filler. I think the stuff is great. In the container it is the consistency of peanut butter and as smooth and creamy. Add a little water, stir for a minute [or less] and it is just as smooth . Any lump disappears when you paint it on. Dries very quickly. Sands easily with low dust.
And welcome to the Forum. Greetings from Southern Nevada.
 

peeler5150

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The main reason why I try the composite motors is for the unique exhaust and the initial thrust off the rod. Mainly, W produces white flame and T produces blue flash. The BP motors are more slow burning and composite faster off the rod. Faster means it flies straighter and less likely to arc over if the rocket is heavy or less aerodynamic.
 

samb

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Welcome to the party peeler ! Had to look up the Sky Metra as I hadn’t seen that one before. Pretty cool ! Stagers get up in air pretty quickly and can also get pretty far down range under parachute. Where will you be flying this puppy ? My suggestion is to fly it single stage with a B6 motor to gauge the winds aloft and possibly adjust your position on the field to maximize your recovery area. As mentioned on the webpage, having a streamer ready to replace the parachute when you add the booster is a good idea. Having a couple of spotters in the crew will increase your odds of recovering everything. Good luck and yes, PICTURES ! :)
 

peeler5150

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Welcome to the party peeler ! Had to look up the Sky Metra as I hadn’t seen that one before. Pretty cool ! Stagers get up in air pretty quickly and can also get pretty far down range under parachute. Where will you be flying this puppy ? My suggestion is to fly it single stage with a B6 motor to gauge the winds aloft and possibly adjust your position on the field to maximize your recovery area. As mentioned on the webpage, having a streamer ready to replace the parachute when you add the booster is a good idea. Having a couple of spotters in the crew will increase your odds of recovering everything. Good luck and yes, PICTURES ! :)
Flying it may be a problem here in Salem, OR. As long as I can get permission from a landowner and a city permit I should be okay. I wanted a rocket with two stages and payload space. It is a learning experience. Modifications include plywood fins instead of balsa, an ejection baffle with a wad of wire inside, nose weights if needed. I'm not looking for 1,000 feet. If it gets off the ground at all I will be happy.
 
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