1/4A & 1/2A motors: How Common?

To make a long story short, when I jumped into Model Rocektry two years ago, a local mom and pop hobby store made me an offer to sell off to me their entire collection of motors...all of it, for a round number. As a newbie, I did a quick mental calculation and realized it was a hell of a deal. Pulled out my wallet and let them charge it to my plastic.

Among the various older Estes rocket motors were a couple of packs of 1/4A and 1/2A as well as some B4-4, B6-0,B-2. B6-4, B6-6 .... some 17 packages in all.:surprised:

After building a PONG rocket, (just cause it looked neat and was a challenge), I inserted a smaller value engine than was recommended. The rocket launched, clearing the pad, but before the chute could deploy, it had impacted the ground, snapping a fin or two. Fortunately, the local old hands were quick to jump in with some CA and immediate curing spray, but also took a look at what I was trying to fly on. They pointed out that the rocket was way under-power with such a weak motor. Fortunately, a vendor at the club launch had the right value for sale, and it flew. :clap:

So, it was in this way that I came to understand how motor's were classified.

So, now I have a handful of these older 1/4A and 1/2A motors left over. And no real use for them, yet.

Just how common is it to require an 1/4A or 1/2A motor in a rocket these days? Have I invested in something that there is no call for? ( I wouldn't be upset :sigh:... after all, the mom and pop shop were divesting them for a reason...and they had dust on every package from hanging on the pegboard for years...)

1/4A and 1/2A motors are perfect in small, lightweight rockets - I used an 18mm 1/2A6-2 this weekend in an old Stardart kit (BT-20 body tube) for a perfect, not out-of-sight flight. The Pong is obviously not a good match. Estes recommends up to a C6-7 for the Stardart, but with the size of the field (large), and height of the grass (6-8 inches), I used the 1/2A motor to make sure I could see where it went.

They're far from useless, just need to match the rocket, field, and conditions. And don't feel bad about buying motors that you have no rockets for - it gives you an excuse to buy and build more rockets... 😄

Hope this helps.
Chris

Here are some kits that use both the 1/4A and 1/2A motors:
https://fliskits.com/products/rocketkits/kit_detail/wcmci.htm
https://fliskits.com/products/rocketkits/kit_detail/tumbleweed.htm
https://fliskits.com/products/rocketkits/kit_detail/cougar660.htm

And some that will work with the 1/2A motors:
https://fliskits.com/products/rocketkits/kit_detail/mercury_redstone.htm
https://fliskits.com/products/rocketkits/kit_detail/saturn_1b.htm

I had never flown a 1/2A until earlier this year when my club did a NAR contest. One of the events was the 1/2A parawad, I mean parachute, duration contest. All of my chutes came out wadded up and refused to open. That's what happens when you shove a big parachute into too small of a rocket.

The tiny 1/4 and 1/2 A motors are perfect for motor eject rockets like the Quark, the Mosquito, the 220 Swift, as well as nose blow like the Star trooper and other small rockets that on an A10 would be single use (because they'd blast off so fast and so high you would never see them again).

I fly 1/2A minis a whole lot in the horse pasture on my small mini-engine kits. One of my daughter's rockets is one from the Estes 3 Bandits triple kit and it flies great on those motors. I have flown 1/4A in a Gnome but it was low - those motors are best suited for mosquitos and the like.

I bought a Bulk Pack of 1/4A3-2's and built rockets just for them. I get as much kick from them as any other BP rocket. I designed a couple BT55 based ones, very light with hollowed out balsa cones, they're fun to launch and they don't disappear.

Actually, I have used the 1/2A3-4T in my Alpha with an adapter - flew just great for spot landing! I don't use the 1/2A6 any more because it just seems underpowered compared to the 1/2A3. And the 1/4A3-3T is great in any minimum diameter BT-5 model - I made a whole series of downscales that will fly on 1/4A (the 220 Swift nose cone works great for doing an Alpha downscale, while the Quark cone looks good when downscaling the Der Red Max, Cherokee D and Goblin!).

Remember that the letter indicates the total impulse, which is average thrust X burn time. Impulse determines altitude. But in order to get a rocket off the pad, you need enough thrust. Impulse has nothing to do with whether or not the motor can lift the rocket off the pad.

Initial thrust equates to: can I get this rocket off the pad, or will it sit there and burn.

Average thrust equates to: will this rocket go straight up once it's off the pad.

Total impulse equates to: how high will it go once it gets off the pad going straight.

If you can lift your rocket with 3 Newtons of thrust, then a 1/2A3 and an A3 both have 3 Newtons of thrust (you would have to look at the thrust curve to see the initial thrust). But the A would go twice as high (presumably) as the 1/2A.

1/4 and 1/2 A's are lots of fun but you need to think like you are building micromax. The Fliskits Whatchamacallit refeerenced above was a great first kit for my boys and it's just right for the little ones to see it all and not worry about losing their rocket.

mjennings said:

The Fliskits Whatchamacallit refeerenced above was a great first kit for my boys and it's just right for the little ones to see it all and not worry about losing their rocket.

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The little ones not losing their rocket on the first flight is so very important. One day while I was driving the CMASS shuttle between our parking area and the launch field, I brought in a father and his two small children. One of the kids (about 5-years-old) had an Estes Quark that he had decorated very nicely and was proud to show it to me during the inbound trip. The family had a pronounced Eastern European accent. I was still driving when the family left a little while later and the child was inconsolable. As happens with Quarks, they are hard to get back, even with the smallest motor. I don't know what he was saying in his native tongue but I was able to pick up on one word - "rocketa".

we have several of the 13mm mount kits. my kids LOVE them. Perfect size for my 2 year old. (His photo with one is on the Watering Hole page today in this forum). The A10's in those kits make for some solid/fast liftoffs and 500-600 foot flights. Perfect. The EX-200 is our favorite kit on these. I think I have 3.

As several have posted 1/4A , 1/2A and A impulse 13mm motors are a hoot for just about any BT-5 size model. Keep them on the lighter side and you'll be surprised at the flights.
There are a complete array of competition events for each impulse level 1/8A (MicroMaxx), 1/4A, 1/2A, and A. One that I particularly like is 1/4A HD.

KennB said:

The little ones not losing their rocket on the first flight is so very important. One day while I was driving the CMASS shuttle between our parking area and the launch field, I brought in a father and his two small children. One of the kids (about 5-years-old) had an Estes Quark that he had decorated very nicely and was proud to show it to me during the inbound trip. The family had a pronounced Eastern European accent. I was still driving when the family left a little while later and the child was inconsolable. As happens with Quarks, they are hard to get back, even with the smallest motor. I don't know what he was saying in his native tongue but I was able to pick up on one word - "rocketa".

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indeed, poor little guy. Losing your first bird at any age is rough. Yeah quark's and mosquitoes are not good first rockets to easy to lose.

plus the other benefit of the 13mm motors is you don't need a very large field, and as we all know good fields are sometimes hard to find

Get a Birdie for your extra 1/2A's, it's a hoot. I had one of the original ones in the early 70's that used the -S short motors. It inspired me to make my first scratchbuilt... a small whiffle ball with a -S motor mount in it. The holes lined up perfectly with the launch rod.

OK, more to point:

Here's a list of the packages and sizes that I still have from that initial mass purchase. Are there any particular Flis-kits (or others) that you'd recommend to "use them up"?

1/2 A 6-2

1/4 A 3-3T


B6-0
B6-2
B6-2
B6-6
B6-6 Upper
B6-6 Upper
B6-6 Upper
B6-6 Upper

It's the smaller ones that I'm most concerned about using up.

Kirk G said:

OK, more to point:

Here's a list of the packages and sizes that I still have from that initial mass purchase. Are there any particular Flis-kits (or others) that you'd recommend to "use them up"?

1/2 A 6-2
1/2 A 3-2T
1/4 A 3-3T
1/4 A 3-3T

B6-2
B6-2
B6-2
B6-0
B6-4
B6-4
B6-4
B6-4

It's the smaller ones that I'm most concerned about using up.

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The Fliskit recommendations I made in Post #3 are all 13mm sizes. All of them will fly nicely on their suggested motors so it would be up to your taste and preference as to which kits to get.
For your 1/2A6 and B6 motors, the same applies for any of the 18mm kits that use those.

I guess I had overlooked the fact that the 1/2A6-2 were 18 mm. Anyone know of a specific rocket that calls for this bird?
It just seems odd to me, as it's not a lot of impulse, but a quick delay, in a larger, heavier motor. Who would call for that?

I've got only one pack of 1/4A3-3T left. I suppose I could put them in a Tinee glider and see if it will fly. (I love the CiCi by Edmunds Aerospace and so glad I picked them up while still available.)

I think I also have a Quark that's never flown yet.

Thanks for your recommendations.

A 1/4A3 is about the ONLY thing that doesn't make a Quark or similar short tumble rocket vaporize!

Kirk G said:

I guess I had overlooked the fact that the 1/2A6-2 were 18 mm. Anyone know of a specific rocket that calls for this bird?
It just seems odd to me, as it's not a lot of impulse, but a quick delay, in a larger, heavier motor. Who would call for that?
...
Thanks for your recommendations.

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The Estes Scout is great on a 1/2A6-2.

Banzai88 said:

A 1/4A3 is about the ONLY thing that doesn't make a Quark or similar short tumble rocket vaporize!

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The problem is the Quark and 220 Swift don't tumble...they lawndart. If they did tumble, you'd have a fighting chance of seeing them on the way down.

I'm fond of Star Troopers....it's plenty small while still being recoverable. But yes, you are pushing your luck on a full A.

For the 1/2A-2T motors, you don't even need a kit. Try some of the free 13mm cardstock oddrocs that Art Applewhite offers: https://artapplewhite.com/free.html

All you need is some 110 lb cardstock, a knife or scissors, and some glue.

+1 on Art Applewhite, try the Pyramid, easy and fun.

KidShelleen said:

+1 on Art Applewhite, try the Pyramid, easy and fun.

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I've taken your recommendation, and printed off the instructions for the Pyramid...and think I might use one of my remaining 1/4A's on it shortly, if not this weekend.

I note the instructions suggest that Art Applewhite would like photos or notice that you use his plan.
Where Do I send this? Is he still around and is it a nice thing to do?

Kirk G said:

I note the instructions suggest that Art Applewhite would like photos or notice that you use his plan.
Where Do I send this? Is he still around and is it a nice thing to do?

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The only contact info I see on the site is [email protected].

KidShelleen said:

The only contact info I see on the site is [email protected].

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It worked, I'm in contact with him.