Search found 118 matches

by heada
Tue Jan 08, 2008 2:49 am
Forum: Rocket forum
Topic: Nozzle Geometry
Replies: 5
Views: 3301

Will burnsim give you the numbers you're looking for?

http://burnsim.com/

-Aaron
by heada
Wed Jan 02, 2008 1:26 am
Forum: Valveless pulsejet forum
Topic: For your viewing pleasure...
Replies: 3
Views: 1624

I'll admit my total ignorance to jam jars, but couldn't you cool the jar walls so that you don't have the huge thermal difference? Maybe put it in a outer container that had enough glycol in it to come up the walls of the jam jar? (glycol used because it has the same refractive index as glass, so it...
by heada
Wed Jan 02, 2008 1:22 am
Forum: Ramjet forum
Topic: ramjet vehicle performance estimation tool
Replies: 17
Views: 12269

Cd for a ramjet

This spring (once things thaw out a bit) I'd be willing to launch a rocket with and without a ramjet attached to determine the true Cd of the ramjet. I have an ARTS2 (as well as a few other recording alts) which can calculate the Cd at each sampling (200Hz) Once we have Cd for the rocket at various ...
by heada
Wed Dec 26, 2007 6:15 pm
Forum: Valved pulsejet forum
Topic: Injecting water into an engine?
Replies: 19
Views: 13719

water injection

There has been talk in some rocketry circles about using water injection as a thrust enhancer. It has mostly been shot down because you have to carry the water with you and rather than carry water you can just carry more fuel/oxidizer (LOX and LH2, which is just what water is anyway) For a ground ba...
by heada
Sat Dec 01, 2007 12:50 am
Forum: Ramjet forum
Topic: how to use RJSC?
Replies: 4
Views: 3595

ramjet stages

I ran across the NASA engine simulator before and it might be something you want to play with http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.html (select ramjet on the top, then you can tweak the settings for a ramjet) There is also basic design layout and the formulas needed to calculate thrust. ...
by heada
Wed Nov 28, 2007 6:36 pm
Forum: Ramjet forum
Topic: how to use RJSC?
Replies: 4
Views: 3595

jet fuel

Welcome! I'm not familiar with the RJSC so I can offer no help there. As for "jet fuel" RP1 and RP5 are two very common "jet fuels" that I know about and they are just kerosene at different levels of refinement and levels of contaminates. You can get away with using straight kerosene as jet fuel and...
by heada
Mon Nov 26, 2007 1:02 am
Forum: Ramjet forum
Topic: My Maggie Mugs Clone
Replies: 45
Views: 23374

Welding or brazing aluminum is very difficult. If you can swap the aluminum for steel, I would. If you can't, then get some scrap aluminum and practice brazing it. If you use the silver braze that you have to use for the stainless then it should have a higher melting point than the aluminum and the ...
by heada
Tue Nov 20, 2007 9:13 pm
Forum: Rocket forum
Topic: BBQ Engine
Replies: 2
Views: 2579

The benefit of using N2O is that it is safe¹ as an oxidizer until it decomposes ( (2) N2O -> (2) N2 + O2 ) It decomposes at about 450°F and thus most hybrid rocket motors contain a preheater of some sort (either a slug of normal propellant or use GOX (gaseous oxygen) and high voltage spark) Also, mo...
by heada
Thu Nov 15, 2007 6:04 am
Forum: Valveless pulsejet forum
Topic: liquid propane from torch bottles?
Replies: 4
Views: 2119

Nitrous is a wonderful oxidizer but be careful of flashback (can happen, has happened in rocketry) as well as decomposition (decomposes at 450°F into (2) N2 + O2) If nitrous starts to decompose on you, you will have "a very bad day"™

-Aaron­
by heada
Thu Nov 15, 2007 5:54 am
Forum: Ramjet forum
Topic: Ducted Ejector Ram Rocket Solid Fuel
Replies: 7
Views: 6748

For a NASA study of just what you're suggesting: http://gltrs.grc.nasa.gov/reports/1997/TM-107422.pdf Note, the fuel was JP-10 (jet fuel, highly refined kerosene) and not a solid like you're describing. Also, since you're in Iowa and one of the best groups for AM/EX rocketry is based in Quad Cities:...
by heada
Wed Nov 14, 2007 6:59 am
Forum: Ramjet forum
Topic: Ducted Ejector Ram Rocket Solid Fuel
Replies: 7
Views: 6748

solid fuel ramjet with rocket motor boost

I have seen ideas similar to this before. Are you envisioning a standard rocket motor just aft of the diffuser(as shown in one of the drawings) or using the entire combustion chamber of the ramjet as the solid rocket motor (also shown in one of the drawings)? If a "standard" solid rocket motor is pl...
by heada
Wed Nov 14, 2007 6:38 am
Forum: Ramjet forum
Topic: air requirements for a large subsonic ramjet
Replies: 8
Views: 5888

4Runner Powered Wind Tunnel

The 4Runner I have has the ability to do 2WD, 4WD limited slip, 4WD locked diff and 4WD low locked diff. I knew that with an open or limited slip diff it would never work (and I knew I'd have to run it in locked diff mode, just a button push away) The 4Runner is over 7 years old and has been paid of...
by heada
Thu Nov 08, 2007 6:15 pm
Forum: Ramjet forum
Topic: air requirements for a large subsonic ramjet
Replies: 8
Views: 5888

air requirements for a large subsonic ramjet

Something that has been rattling around in the back of my mind is a possible method of creating massive amounts of "high speed" air. The problem with most fans is that they're either they're too small to generate large volumes of air or they're large enough to generate the volume but not the higher ...
by heada
Fri Nov 02, 2007 6:08 am
Forum: Ramjet forum
Topic: My Maggie Mugs Clone
Replies: 45
Views: 23374

Most razing rods that I've worked with melt in the 1000 to 1300 degree F range (550 to 700 degrees C). Propane has a max burn temp of just under 2400 degree C Most propane torches will not get maximum burn temp and will get to about 1800 to 1900 degrees C Obviously you don't need Oxy-Acet to get bey...
by heada
Wed Oct 31, 2007 6:54 pm
Forum: Off topic forum
Topic: Metal/spring problem?!
Replies: 3
Views: 1818

DISCLAIMER: This is what I have done for high-carbon steel. I have not done this for very thin metals like springs and so it may not work or it may not have the desired outcome. What you have done is annealed the iron. What you now need to do is harden the iron. What you should do is heat the spring...