Mach 4, 144,000' HPR flight.

[XolveJohn]

https://news.usc.edu/100968/usc-rocket-propulsion-lab-shoots-for-the-stars/

https://www.msn.com/en-us/news/tech...oars-to-record-altitude/ar-BByAuQn?li=BBnbcA1

I saw the onboard video, a round picture, vehicle was rolling badly, need to put the fins
on straight, or use ROLLERONS, an air turbine wheel installed on the fins of some weapons
to restrict roll. Not well known.

I am trying to calculate how to go Mach 4 with 2 stages, FSI F100's clustered in first stage,
then D12's in second stage. I prefer black powder motors! Cheaper than fancy composites.

 

[XolveJohn]

Oops, that is MARCH 4, not Mach 4. Close enough for government work.

Need some new eyeglasses.

 

[dhbarr]

No BP motor ever made ( or combination thereof ) has the necessary ISP to break mach3 or likely even mach2 under their own power.

 

[XolveJohn]

Excuse me, but here is a black powder H40, cluster and stage enough of these suckers and you might go Mach 1. :dark:

https://www.brianredmond.net/dwilliams/rocket/rocket.html

 

[watheyak]

Unfortunately that H motor is fiction. The line "I wish I could capture the effect on film, but a picture just doesn't do it justice." is telling.

 

[TRFfan]

The Fathom II rocket was designed and manufactured by students at the University of Southern California Rocket Propulsion Laboratory (RPL). Fathom II blasted off from Spaceport America in New Mexico, going as fast as four times the speed of sound, according to a statement from USC. The university captured the record-breaking launch on video, including footage from a camera onboard the rocket during the flight[FONT=&amp].[/FONT]

It actually did go mach 4.

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[eggplant]

I saw the onboard video, a round picture, vehicle was rolling badly, need to put the fins
on straight, or use ROLLERONS, an air turbine wheel installed on the fins of some weapons
to restrict roll. Not well known.

Not involved with this team in any way, but jeez... what's your altitude record? There are very few people who could undertake such a project, let alone succeed. I'd say it worked pretty well!

Anyway, as mach number increases, CP shifts forward and stability decreases. One way to counter this effect is to cant the fins to induce roll, which spin-stabilizes the rocket. It is very possible that the spin was intentional. Many sounding rockets such as the GoFast project have applied this technique.

[video=youtube;001IXnp0ogc]https://www.youtube.com/watch?v=001IXnp0ogc[/video]

 

[XolveJohn]

Watheyak: Maybe the ISP is not to spec, the FSI F100's were really just a slightly big E. From the 1960's. But If really H's I can use them.

TRF: that is amazing. My mistakes never cancel themselves out.

Egg: that rocket is rolling FAST. You must be reading my mind.

I envision a vehicle with 7 engines. 3 stage. Booster has 4 of the strap-on "H" black powders, the core engine ignites when they fall off. The 3rd stage has to be booking after all that thrust. I was thinking about putting small spin tabs on the fuselage, right at the CG. So that it does not affect pitch or yaw. Rolling uses some energy, but is worth it if there is much wind, avoid too much weathercocking.

 

[watheyak]

Watheyak: Maybe the ISP is not to spec, the FSI F100's were really just a slightly big E. From the 1960's. But If really H's I can use them.

By fiction I mean H motor in the page you linked doesn't exist. A hoax. You can't buy them and making them would be crazy dangerous. There's a reason you don't see any EX black powder motors. Besides, all that tooling would make it WAAAAAAY more expensive than those "fancy" composite motors. And if I'm not mistaken, composite motors are cheaper, newton for newton. They also don't explode every third one like everything Estes 24mm and larger.

 

[Incongruent]

Unfortunately that H motor is fiction. The line "I wish I could capture the effect on film, but a picture just doesn't do it justice." is telling.

I have read and been told that people do make large reliable black powder motors. The issue, if I remember correctly, is storing it as the black powder is brittle and can also separate from the tube.

 

[XolveJohn]

The H40 is not fraud. He is a fireworks guy. Anyone using load cells, hydraulic presses, titanium powder is not inexperienced. Sure it looks involved, probably not cost effective, but I am still looking for big premade black powder motors that are reliable. Maybe they need some kind of binder like is used in composite types. I would like to get some of the old F7's, they are legendary.