Mid Power 1 Mile Mach 1?

DizWolf said:

Actually, 62.5 - https://www.aerotech-rocketry.com/c...MR-SU_Instructions/g80t_new_su_in_21003-1.pdf

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I stand corrected. That round-off will get you every time. Or in this case, not get you.

DizWolf said:

Not likely to close in on Mach or mile at that diameter though.

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My sim shows 3195ft @ M 0.74 - still haven't had a chance to fly it yet

I started a Sim for this, but it can't be done in Openrocket so I'll just have to build one and fly it with an Altimeter II to find out what happens.
2X29 necked down to a single BT-55. OR won't let me make a FG Shroud around the MMTs nor will it let me attach fins diectly to the tubes. It also assumes that all transitions are round as opposed to flat like mine will be.

scsager said:

My sim shows 3195ft @ M 0.74 - still haven't had a chance to fly it yet

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so sexy....

Area66 said:

Well acording to Open Rocket it's not

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Perhaps the wrong motor. Apogee sells the Aspire bundled with the F10 motor for a mile or the G74 for Mach. Note that it isn't trying to do both with the same motor. I think Tim even suggests different fin profiles for the different objectives. Point being that this is a mod power model.

https://www.apogeerockets.com/Rocket_Kits/Skill_Level_2_Kits/Aspire_Rocket_Kit

1tree said:

Perhaps the wrong motor. Apogee sells the Aspire bundled with the F10 motor for a mile or the G74 for Mach. Note that it isn't trying to do both with the same motor. I think Tim even suggests different fin profiles for the different objectives. Point being that this is a mod power model.

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the OP ask for 1 mile and Mach 1 .... I also question the trust curve of the F10, who certify this motor ?

dhkaiser said:

I have a friend who says some day he would like to fly at Mach 1 and 1 mile. Can it be done mid power? If so what is the smallest motor/rocket combo?

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24mm Carbon Fiber tube (13") with F44-8W will do it, Sims say 5800 feet and mach 1.2. Finding it... yeah, not likely.

swatkat said:

24mm Carbon Fiber tube (13") with F44-8W will do it, Sims say 5800 feet and mach 1.2. Finding it... yeah, not likely.

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look at post # 18 :eyeroll:

Area66 said:

look at post # 18 :eyeroll:

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Yup, but mine is WAY smaller and will do it on an Economax F. I'll post the .rkt file AND a photo of the actual rocket when I can get a chance to here.

I'm surprised no one's mentioned a flying case design. I'd consider this avenue if I were making such an attempt. I'd say it's definitely doable, given the right electronics on-board so you have the snowball's proverbial chance of finding it again...



Later!

--Coop

Area66 said:

the G80 is not the largest motor under 80 N of average trust. The Aerotech G-80 is 136N total, an Aerotech G75J as 157 N total and a CTI G54-RL 160 N total.

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I was simply pointing out that the 80 was the largest average N rating allowed for non-cert flights. I also pointed out that it did not mean it was the best motor. Depending on the build, total impulse does not always mean the best motor for the rocket. I learned that the hard way. But I learned it.

It was routinely done with the OOP Rocket Vision Mach Buster. https://www.rocketreviews.com/rocket-vision-mach-buster-terry-moore-read-5426.html

You want a 24 mm motor in a MD airframe and used a higher thrust, full impulse F or G motor.

Good luck find it! A long metalized mylar streamer is highly recommended. Multiple spotters will help a lot.

Bob

Area66 said:

the G80 is not the largest motor under 80 N of average trust. The Aerotech G-80 is 136N total, an Aerotech G75J as 157 N total and a CTI G54-RL 160 N total.

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Kruegon said:

I was simply pointing out that the 80 was the largest average N rating allowed for non-cert flights. I also pointed out that it did not mean it was the best motor. Depending on the build, total impulse does not always mean the best motor for the rocket. I learned that the hard way. But I learned it.

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He left out an s on the total impulse. Thrust is measured in N (Newtons) and total impulse is Ns (Newton-seconds). The average thrust of a model rocket motor can not exceed 80 N (Newtons). The total impulse of a G motor is 80 Ns < Total Impulse <= 160 Ns (Newton-seconds).

What he meant to say was: The Aerotech G-80 is 136Ns total impulse, an Aerotech G75J as 157 Ns total impulse and a CTI G54-RL 160 Ns total impulse.

You do want to maximize the total impulse because a full G burns twice as long as a minimal G total impulse motor. A minimal impulse G motor will go half as fast and apogee at half the altitude of a full impulse G motor with the same average thrust if you neglect drag losses. In reality, it's always fast and higher, but not quite a factor of 2 due to drag.

Bob

I've left a lot of details out of this design, but it sims out at 1.07 miles and mach 1.06 on a G54.


EDIT: On reflection, this is a little short of valid, because I used airframe material that's too light. (I had started out to design a vehicle for F10s then thought "why not stick something with a shorter burn in it?" I had to extend the airframe tube to get stability with the heavier motor, but I neglected to beef it up from the LP tube that is suitable for 10N thrust to something for the 54N thrust.)

On the other hand, I also did virtually no optimization and WAGed the avionics mass. (That's the mass halfway up the nose cone.) So this at least shows that there's hope.

Area66 said:

so show me the simm, because I can't reach over 5000 feet with Open Rocket.

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Plug in an Apogee F10-8 medalist. The poster did mention two different motors. You are correct, won't do both on same motor. The G80 will do Mach, the 8 second burn F10-8 will do the mile thing. I flew the same Aspire for a couple of years until I think it finally went into a pond. Folks are right, issue is getting the rocket back. If one uses a tracker, the added weight is a problem. A long mylar streamer, fan folded, hit with a moderate iron to heat it up and set the folds and then rolled into the airframe will "rattle" on the way down and can sometimes help with localization if it doesn't go weathercocking off sideways. The silver mylar flashes and one can sometimes see the flashing and no rocket. The G80 is, "Now you see it, now you don't." The F10-8 burns for 8 seconds and the rocket just climbs, disappears and eventually I couldn't hear it before the burn time was up. Then it had the 8 second delay. Wow, it's funky. I have to admit, I only did one G80, rocket was lost and then returned to me later and I then flew it on five F10's before losing it. I have another dolled up I haven't flown yet. 82 grams is a bit heavy with paint. No streamer installed yet.
Kurt

but late for this but a G150 could easily break mach 1 and a mile.

Dood. Are you going to resurrect every dead thread even remotely close to this topic?

They live in the US, so no more than 80ns avg. thrust in one motor.

DavidMcCann said:

Dood. Are you going to resurrect every dead thread even remotely close to this topic?

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:yawn:

A little late in the game but here is my Super Aspire. I was really scratching my head on how to get one back so I decided on dual deploy. Trying to balance the mass for the magic 1 mile mach 1 mark was a real challenge. Lots of mods on this one. Fins are 1.6mm rock hard acrylic beveled to a paper cutting edge. Fin can is treated with CA on the inside and epoxy on the outside. Polished finish. Numbers reflect my local launch site which is at 5000 feet. Complete weight is 131g with 2 charges of tracking powder. Sorry OR pic is hard to read but altitude is 5804 at mach 1.04.

dhkaiser said:

I have a friend who says some day he would like to fly at Mach 1 and 1 mile. Can it be done mid power? If so what is the smallest motor/rocket combo?

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yes. launch from somewhere that is already over a mile ASL and go for mach.

im wondering what an AT G75 would do in an apogee aspire.

if you want to do this, look on YT for a video from apogee on making mylar streamers. I have one that's about 12" wide and 5' long that folds up nicely into the BT of the aspire and doesn't add much weight.

Motor in the sim is a G64-0 reloadable. If you want to be right out on the edge the G80-14 DMS pushes past Mach and a mile at my old launch site. Muncie Indiana, a little over 700 feet above sea level. The deploy timing is right on the edge though. Risk a yard sale in the sky.