Are there any low and slow rockets for AEROTECH 29MM PROPELLANT KIT - G25W-10?

[Underdog]

I was planning on a nice low and slow rocket build over the winter. I noticed that AEROTECH's G25W-10 has a long burn time and will fit in my reloadable casing. I just can't seem to find a rocket that will match up and meet the "low and slow" criteria. I built a longer launch rod over the summer in hopes of finding something.

 

[mbeels]

How long is your launch rod? Have you considered a rail? They can be longer because they aren't as floppy as a rod.

What are your "low and slow" criteria? This is where a good simulation (Open Rocket or RockSim) is useful, because you can simulate the expected velocity of the rocket off the rail.

I'm expecting that as long as my Plasma Dart 2x comes in under 20 oz, it will be a candidate for the G25. I'm considering another scratch built rocket specifically for this motor, I also like long burning motors.

 

[dhbarr]

Be aware that's the 29/120 HPR casing, not the more widely distributed 29/40-120 Hobbyline.

With a 5+s burn time, slow should be no problem but low is potentially a challenge. You'll want something fat and stubby.

 

[mbeels]

With a 5+s burn time, slow should be no problem but low is potentially a challenge. You'll want something fat and stubby.

Yeah, there are plenty of rockets with 29mm motor mounts light enough to fly on the G25, but they're going to go really high. Look for something light and draggy.

 

[neil_w]

Dang, I would seriously *love* to fly that in my upscale Quinstar.

 

[3stoogesrocketry]

Tetrahedron or saucer

 

[Underdog]

How long is your launch rod?
What are your "low and slow" criteria? This is where a good simulation (Open Rocket or RockSim) is useful, because you can simulate the expected velocity of the rocket off the rail.

I'm expecting that as long as my Plasma Dart 2x comes in under 20 oz, it will be a candidate for the G25. I'm considering another scratch built rocket specifically for this motor, I also like long burning motors.

I misspoke, it is a rail (not a rod). I measured it at 8 feet in length. Someone on the forum recommended the "Binder Design Jackhammer." As attractive as the Jackhammer is, the motor mount is a 38mm and this does not sound "low and slow." I wanted to keep it under 1000 ft. I will check out the Plasma Dart 2x.

 

[Handeman]

I don't thing you are going to find anything that is light enough to fly on the G25 that will stay under 1000 ft with that long burn time unless you go with a saucer or something similar like 3stoogesrocketry said. You might be able to scratch together something light and very draggy.

 

[Underdog]

How lite are we talking? 40 ounce?
What about a stubby Minnie Magg?

 

[mbeels]

How lite are we talking? 40 ounce?
What about a stubby Minnie Magg?

I think that 40 oz will be too heavy for the G25. As a starting point, the 5:1 rule of thumb puts the total rocket weight around 18 oz.

 

[Underdog]

An overbuilt Super Big Bertha (with plywood motor mount centering rings, an eyebolt and a baffle ) might be close to that weight. Berta’s are pretty draggy. The nose is very blunt and there are 4 fins

 

[Underdog]

Be aware that's the 29/120 HPR casing, not the more widely distributed 29/40-120 Hobbyline.

With a 5+s burn time, slow should be no problem but low is potentially a challenge. You'll want something fat and stubby.

Oh, my mistake. I thought they were the same. Thanks for catching that. I'll start looking for another "low and slow" motor. I see the that Estes recommends the F15-6 for the Super Big Bertha. That has has a 3.5 second burn time, not sure how high it would go. (still trying to figure out OpenRocket). I might have better luck with something like that for now.

 

[mrwalsh85]

Be aware that's the 29/120 HPR casing, not the more widely distributed 29/40-120 Hobbyline.

Technically, the G25 was once a SU motor in production.

I have a few kicking around my range box. Those are some nice long burning motors. Flew one in an Aerotech Mustang. That was pretty impeccable for 15 year old me. Wonder if that will hold true, 18 years later.... Might have to wait for 19. Or 20... or...

 

[grouch]

I have one G25 reload for the 29/120 case. I've had it kicking around my motor pile for a couple of years now. I plan to fly it in a Loc Onyx which should be a perfect rocket for it. Stubby, draggy and light enough to get moving on a G25.

 

[SDramstad]

I fly them a lot in my saucer. Also had a ring fin rocket that it worked well in.

 

[AfterBurners]

Maybe a Sumo?

 

[swatkat]

I have three of them left, I use them in a shortened (1.3 tube) Leviathan. 13.1 Oz takeoff weight + motor is just about the most I'd chance on a 5 foot rail. 6 footer or higher and you could likely get away with 16 Oz+. Delay will need to be shortened a bit for low and slow! 6 Seconds is just about right on the shortened Levi.

 

[ThirstyBarbarian]

Most flights that are “low and slow” do not use “slow” motors that burn for a long time. They use fast, high-thrust motors that burn out almost immediately after clearing the rail at a safe speed. The “low and slow” part is that they slowly coast up, not under thrust, and they don’t coast very high. Fat rockets with lots of drag are good for this. I have a Warlock that I sometimes do these kinds of flights on. Instead of using a standard medium-thrust J motor, like a J290, I use a fast-burning motor with a lot less total impulse, like an H295, or H399 to pop it up to just 600 feet or so. It’s a hoot!

Long-burn motors are mostly for altitude shots. Put a G25 in a skinny rocket with the right weight, and it will just keep going and going.

That said, I know EXACTLY the kind of flight you are talking about, and I like that kind of flight too. What you want is a long burn, with the motor thrusting for a long period, but the rocket never gets up much speed and doesn’t go too high. The kind of flight that is more “realistic” and similar to space launches. It’s not an easy thing to pull off, and most commercial kits are not designed for it. You may need to scratch build it and use some non-standard materials and techniques.

What you need for that kind of flight is an extremely light, wide-diameter rocket. Some people suggested saucers. What makes a saucer work is that it is very light, so it gets up to a safe speed quickly, but it is so wide, that drag takes over immediately. The motor spends most of its energy fighting drag. Look for a rocket that is light enough to get off the rail at a safe speed but fat enough to have some saucer-like drag characteristics.

If you look at the thrust curve for the G25, it starts off pretty weak, which is not ideal for what you are trying to do. An initial thrust spike and a curve that tapers off would be better. With that weak start, you probably don’t want a combined fully loaded weight of more than 1 pound. But for drag, you might want the rocket to be 4” or so in diameter. You will probably need to look at scratch building something out of foamcore board and adding a skin, or cutting it entirely from foam.

 

[tomsteve]

Most flights that are “low and slow” do not use “slow” motors that burn for a long time. They use fast, high-thrust motors that burn out almost immediately after clearing the rail at a safe speed. The “low and slow” part is that they slowly coast up, not under thrust, and they don’t coast very high. Fat rockets with lots of drag are good for this. I have a Warlock that I sometimes do these kinds of flights on. Instead of using a standard medium-thrust J motor, like a J290, I use a fast-burning motor with a lot less total impulse, like an H295, or H399 to pop it up to just 600 feet or so. It’s a hoot!
/QUOTE]

mini magg on an I218 is another example. i loved that combo. lots of sound for 1.5 seconds then 7-8 seconds of coast.

 

[dpower]

I use G25 motors primarily for my Priority Stealth.

 

[BABAR]

An upscale of the Apogee Rockets SloMo would be a really cool flight on a long burn motor

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-3-Model-Rocket-Kits/Slo-Mo

 

[Mr G]

Estes/Semroc Saturn 1B and Saturn V modified for a 29mm motor mount are ideal candidates.

 

[Howie]

I'm thinking along similar lines: I have an Estes Saturn V and a Semroc Saturn 1B in my build pile. Planning to build both with 29mm mounts and try both on a G25. According to Rocksim, and taking the weight of my current 24mm SV plus the nose weight to make it stable, it comes to 21 oz. With these factors in the simulation, altitude is just under 1000'.

 

[shreadvector]

I was planning on a nice low and slow rocket build over the winter. I noticed that AEROTECH's G25W-10 has a long burn time and will fit in my reloadable casing. I just can't seem to find a rocket that will match up and meet the "low and slow" criteria. I built a longer launch rod over the summer in hopes of finding something. View attachment 391389

I did not notice if anyone else mentioned this, but the "-10" indicates a stock 10 second delay time, which will result in a crash for anything that flies low and slow. You will need to drill the delay using the Aerotech instructions. I would drill in at least 3/32 inch (or .10 inch) to reduce the delay 3 or 4 seconds. Don't drill too much. I would suggest a maximum of .16 inches if you want a short delay.

https://www.aerotech-rocketry.com/c...tions/RDK_Instructions/rms_delay_mod_inst.pdf
https://www.aerotech-rocketry.com/u...5-9a389d14be23_29_120_g25w-10a_in_20054-1.pdf

Per NFPA, the G25 should be a Model Rocket Motor reload.

Since this was Classified by the CSFM during the "bad years", it was Classified as an Experimental High Power Rocket Motor.
https://www.aerotech-rocketry.com/u...1e-b956-4b8043d5a2b5_csfm_hp_appr_2-18-14.pdf

This should be changed to Model Rocket. Will anyone at Aerotech be reviewing the reloads classified during those bad years and then submitting a request to have them re-Classified as Model Rocket Motors by the CSFM?