Rack staging questions

Hey everyone, I wanted to do a rack stage rocket but wanted to see if anyone else had done it. I put this in low power section because that would be the only practical way within my budget. Has anyone tried, succeeded, failed at this? Please share.

Ummm... at the risk of sounding stupid... What's rack staging??

Never heard of it...

Later! OL JR

Here's a link...

LUNAR Clips Rack Rocket Plans

Ingenious method of doing multiple stages in a Rube Goldberg sort of way.

The downside is that the spent motors are ejected from the rocket.

A good thread here: https://www.rocketryforum.com/showthread.php?t=21672


I like what he did there. Good thinking.

That previous thread mentioned the "Krushnik" effect. (Way, way back in jr. high school I did a science project on the Krushnik effect- built a thrust/curve machine and everything.) Also you have to worry about burning the inside of the airframe/rack.

An interesting forerunner of rack staging was the "Lil Augie" rocket design.

https://www.rocketreviews.com/lil-augie-with-booster-motor-in-module.html

https://www.rocketreviews.com/descon-augie-sport-frank-ross.html

foamy said:

A good thread here: https://www.rocketryforum.com/showthread.php?t=21672


I like what he did there. Good thinking.

Click to expand...

Thanks! I like what I did too! It flew great...straight and about 2800 feet! That was under my old sign in name.

bjphoenix said:

That previous thread mentioned the "Krushnik" effect. (Way, way back in jr. high school I did a science project on the Krushnik effect- built a thrust/curve machine and everything.) Also you have to worry about burning the inside of the airframe/rack.

An interesting forerunner of rack staging was the "Lil Augie" rocket design.

https://www.rocketreviews.com/lil-augie-with-booster-motor-in-module.html

https://www.rocketreviews.com/descon-augie-sport-frank-ross.html

Click to expand...

I used a tube coupler on the rear tube/airframe and then coated it with epoxy to help prevent burning the inside of the tube...it worked out well. The hardest/time consuming is building the air duct system.

Here is an article I wrote and had published on Rocketry Planet...goes into great detail on how to build one from start to finish...

https://www.rocketryplanet.com/content/view/3654/38/

To avoid the krushnik effect and the tubes being desintegrated, I was going to use 4 dowels which the fins would mount on to, fireproofed somehow, most likely aluminum tape, if I can find it...
Edit: it would look a bit like the LUNAR rocket pointed out bit cranky kong

Ta.anders said:

To avoid the krushnik effect and the tubes being desintegrated, I was going to use 4 dowels which the fins would mount on to, fireproofed somehow, most likely aluminum tape, if I can find it...

Click to expand...

I used basswood for the strakes and supports at the rear, balsa fins. Usually lost on D-D-D-E motors, if found good for 1 or 2 more flights with just raw wood. I don't bother painting them as it only costs about $4 to build.

Rocketjunkie said:

I used basswood for the strakes and supports at the rear, balsa fins. Usually lost on D-D-D-E motors, if found good for 1 or 2 more flights with just raw wood. I don't bother painting them as it only costs about $4 to build.

Click to expand...

What kind of engines are those in the picture? Cobras? never heard of then...

Rocketjunkie said:

I used basswood for the strakes and supports at the rear, balsa fins. Usually lost on D-D-D-E motors, if found good for 1 or 2 more flights with just raw wood. I don't bother painting them as it only costs about $4 to build.

Click to expand...

the basswood survived he flights without being painted?

Ta.anders said:

the basswood survived he flights without being painted?

Click to expand...

I have a 2 rocket that has sticks that go down 6'' from a Bt'50 tube and at the end has fins on the sticks...I painted it, but you cant even tell the marks, just a little smoke residue. C6-5= good flight, 2 flights so far.

[POW]Eagle159;243013 said:

What kind of engines are those in the picture? Cobras? never heard of then...

Click to expand...

Estes D12-0 from 10-15 years ago. They branded them Cobras for a while.

[POW]Eagle159;243013 said:

What kind of engines are those in the picture? Cobras? never heard of then...

Click to expand...

Estes packaging from the 80's... they were all marked "Cobra" back then with the alternating and thinning black and gray stripes...

Still have some 80's motors in my box but I don't think I have any of the "Cobra" packaging anymore... they used the same motif on their ignitor packaging and wadding packages... I think it replaced the bright reddish/pink motor hangtag packaging and ignitor/wadding packaging... (I have some of those too-- old hobby shop stock I bought back in the 80's).

Later! OL JR

Yeah, I have done as few rack rockets. Mine are D12-0/D12-0/D12-0/E9-8. Original designs used just straight pieces of 5/32" OD hollow brass tubing for the struts, but they failed about a second into the 4th stage burn (Max-Q). Now I see a piece of wood to brace the fins to each other near their base, and it seems to be OK.

I love rack rockets.

Here is a great link on rack rockets, and History Lesson, Pt.1 -

https://members.tripod.com/tripoli_rocketry_pgh/rackrocket.html