2025 Build - 8" 4 Fin 98mm

[rfjustin]

Thanks to @PSLimo, @jsdemar, @Conway Stevens, @Wingarcher, @WILDMANRS, @David Schwantz I have some 8" parts that need to get built this winter. I got "stuck" with a 54" booster that has (3) 20" slots and the tube is out of round where the fin slots are, so we will need to fix that first before we turn this into a 4 fin build. Should hold a 54-56" long 98 motor with room to spare. Lots of work ahead...

 

[rfjustin]

When the booster is done, using some tricks I've learned, should resemble something like this.

 

[crossfire]

Looks like a fun winter build

 

[StreuB1]

Woohooo!!!

This is gonna be another good one!

 

[rfjustin]

Split a 17" long piece of airframe to make a coupler for the booster. Got some material removed, but there is more needed to go. This will help help support the fin slotted section which is "caved-in" a bit. Perhaps this tube was wound a little tight and the slots caved in a little?

I dont want to add more weight to the rear, but its an easy way to get this tube back round. All these components were sourced prior to Tim taking on CT/CW business so I am trying to make work what I have.

 

[rfjustin]

Plugging and re-using some coupler bulk heads for the booster. Also need to work on a repurposed coupler as well.

 

[pugachu]

Should hold a 54-56" long 98 motor with room to spare. Lots of work ahead...

Isn't the N4000 like 52" long, with the CTI 98-6GXL shorter?

What do you have planned????

 

[rfjustin]

Isn't the N4000 like 52" long, with the CTI 98-6GXL shorter?

What do you have planned????

The 4K is just a hair shy of 54" OAL.

Vented the rear centering ring to accommodate the beginnings of a tail cone being formed.

 

[BNev]

That's going to be a monster!

 

[Theory]

Is the conical nose cone going to be cut for the tail cone? I’ve had this idea bouncing around in my head for some time, could also be used to make a beefy transition, though that’s a different project…

 

[rfjustin]

Is the conical nose cone going to be cut for the tail cone? I’ve had this idea bouncing around in my head for some time, could also be used to make a beefy transition, though that’s a different project…

No sir that's the primary cone.

All shall be revealed in time.

 

[rfjustin]

Got (6) strips of glass reinforcing the newly made coupler curing. Was going to use (4), but ended up with extra resin, so figured cut and add two more right quick. Looking forward to seeing the result in the morning.

 

[Theory]

No sir that's the primary cone.

All shall be revealed in time.

Nice! Conical nose cones FTW!!!!

 

[rfjustin]

Coupler came out clean.

 

[rfjustin]

Got the makeshift coupler glued in. That was a PITA getting it glued in and seated where it needed to go. This was a rather major hurdle that needed to be tackled out of the gate.

 

[Bobrogg]

Got the makeshift coupler glued in. That was a PITA getting it glued in and seated where it needed to go. This was a rather major hurdle that needed to be tackled out of the gate.
View attachment 682721

And all that time the epoxy working/pot life is counting down, congrats on getting that step completed

 

[rfjustin]

 

[ECayemberg]

8" Glass???

Keep it out of the corn fields, please!

Looking good, sir!

 

[rfjustin]

8" Glass???

Keep it out of the corn fields, please!

Looking good, sir!

"Keep it out of the corn" = dont fly it at Bong.

 

[ECayemberg]

"Keep it out of the corn" = dont fly it at Bong.

Or just...no left turns!

Looking forward to more drippy fillets and G-string tailcones!!!

 

[loopy]

Or just...no left turns!

Looking forward to more drippy fillets and G-string tailcones!!!

I...um...hmmm...I got nothin'...

 

[kramer714]

Split a 17" long piece of airframe to make a coupler for the booster. Got some material removed, but there is more needed to go.View attachment 682590 This will help help support the fin slotted section which is "caved-in" a bit. Perhaps this tube was wound a little tight and the slots caved in a little?

I dont want to add more weight to the rear, but its an easy way to get this tube back round. All these components were sourced prior to Tim taking on CT/CW business so I am trying to make work what I have.

With filament wound tubes there are thermal stresses that want to make the tube smaller diameter, you don't see them until you cut the slots. Round starts to look like a 4 leaf clover after slotting.

I use small 3/32 countersunk rivets to hold the tube round against a closeout. You can do this on the outer tube or on a couple since they are countersunk and small enough the head can be 'buried' in a fiberglass body tube. They are the 'clamps' for bonding.

These small rivets are the same as used to hold nutplates. reason i say is you find them on E-Bay sometimes listed as nutplate rivets. For scale that is a 4" diameter. Nut Plate RIvets on E-Bay

 

[rfjustin]

Altimeters from Chris and sleds from Jim have arrived.

 

[rfjustin]

 

[rfjustin]

 

[rfjustin]

Yeah I dont think this will zipper anytime soon.

 

[Tractionengines]

Yeah I dont think this will zipper anytime soon.
View attachment 683435View attachment 683436

NOPE... don't see a zipper in the near future for that... wow... (If it does, you have other issues. )

 

[StreuB1]

I cannot for the life of me, figure out the layout of what you are building. I can say though that it is making me want to build an 8" bird now!!! This is not good as I have too many projects currently not moving forward. lol

An 8" Big Daddy would be pretty awesome though!

 

[rfjustin]

I cannot for the life of me, figure out the layout of what you are building. I can say though that it is making me want to build an 8" bird now!!! This is not good as I have too many projects currently not moving forward. lol

An 8" Big Daddy would be pretty awesome though!

Just 4 fins and nose cone, plus a fancy pants mini tail cone. Fins are of a pretty basic/classic shape.

 

[rfjustin]

Dirty nasty slotting work today, should be "easy" here on in.