SpudFiles

Okay, I decided after a thought churned up on a thread to build a caulk tube expandable winged projectile.
The pictures are missing the spring needed to make the mechanism function, and the wings as well as the assembly are all going to be coated with a wood epoxy that will harden them greatly. I'm also planing on making a new "wing spreader" that will spread the wings to about 80 degrees instead of 60.

I will also be making three evenly spaced tail fins and a pneumatically charged tip to be filled with glow stick stuff so that retrieval will be easier with a huge glowing landing spot.

Tell me what you think.

Looking good, reminds me of the sort of high aspect ratio fins you'd find on RPGs and recoilless launchers:



You're going to need more than two to effectively stabilise your projectile though...

Looks neat. Looks like a lot of work for a projectile.
Cool paint.
I forgot to reply back that your barrel paint looked great and unique also.

I do suggest wear gloves when you build those incase they stray off course (they look a little heavy). (sort of jking)

Maybe the stabilizers should open towards the front to prevent them from closing in the wind? Like some archery points do.

I saw a very similar arrow tip that opens from the front on impact. 8)

@JSR I'm going for a slightly more tomahawk style, but the idea is the same

@TL I'm going to use a strong spring to open the wings, so I dont think they will close in the wind, but there is no telling until it has been fired...

daxspudder wrote:I'm going for a slightly more tomahawk style, but the idea is the same

Note that the Tomahawk still has a cruciform tail section, you're going to need some form of vertical fin if you want it to be stable in flight.

Nice work!
Now try to build one wich opens up in 4 directions.
(Or hey, what about 3 fins?)

Though its a bit sad that your result of alot of hard work gets out of your sight within a second.
How much time did you spend on this?

@psycix about 30 minutes...

Im very aware of what a tomahawk looks like, in fact I know so well that I cannot say anymore on how or why I know other than my profession. I am planning on having 3 tail fins evenly spaced. The graphic you show is a TLAM BLOCK III-C, but is inaccurate since the wings on the real thing are very square with only a slight curve on the leading edge. I'm planning on having the intake scoop on the top, since there is only the cannon to propel it, the intake on the top will vent air out of the bottom, helping to create lift, and my wings are crafted into wind-foils but to keep them thin enough to be concealed the lift will be minimal, but should help keep it up a little longer.

I wouldn't bother adding the scoop, it would just create extra drag - when you have high velocity, small wings will still generate enough lift, so it's in your interest to keep the velocity up, therefore you want low drag and high sectional desnity.

Look at any glide bomb design (which is a better analogy to look at than a cruise missile, as it is unpowered), they all have tiny wings which are usually little more than glorified fins.

I'm with Jack on the air scoop creating extra drag. Even though the air will pass through it will be contacting more surface area, the inside as well as the out. I've built many and different kinds of model rockets, the pointer and skinnier, the straighter and faster they flew.

Another thing I noticed about your design. The wood on wood moving parts will be subject to weather (humidity and dew point), binding as well. Maby use pieces of plastic inbetween to keep it from binding, or a dry lube (talc powder, powdered graphite).

Im gonna cast my parts out of epoxy, and the wings are polyurethane coated

Make the wings as thin as possible without becoming bendy and flappy.

I know it has nothing to do with the topic... but is it possible to build a projectile that has drag coef lower than 0.2 ? any idea how to make a homemade low drag ammo...?

BTW it not the best idea to have 3 tailwings 4 are minimum... in case you don't know why read Artis Magnae Artilleriae by Kazimierz Siemianowicz

lol I read this book when I was about 6 years old - I found it somewhere in the basement and I thought "hey that looks interesting"

POLAND_SPUD wrote:BTW it not the best idea to have 3 tailwings 4 are minimum... in case you don't know why read Artis Magnae Artilleriae by Kazimierz Siemianowicz

lol I read this book when I was about 6 years old - I found it somewhere in the basement and I thought "hey that looks interesting"

Since I have not rode then book, could you explain why one would need at least 4 fins?

3 does not work well... don;t ask me why I read it long time ago - anyway have you seen any rocket that has 3 tailwings ?

ya, my rockets with 3 fins fly fine, and would probably fly better with 3 than 4 because the center of gravity would be pushed farther up