AMW White Wolf 5.5" Build Thread

[Big_Red_Daddy]

Trying with a resized photo

 

[Big_Red_Daddy]

Looking in from the aft end. Fins epoxied in. Holes in fins for foam to flow. Holes in middle CR for foam to pass through to forward fins. Thin slow cure epoxy coating the CR is hard to see but it's all around. It's not pretty but it is strong already. The foam should make it even stronger.

 

[Big_Red_Daddy]

Fins are set. I clamped them together with an aluminum angle while the epoxy set. Tried to keep them in line as much as possible for maximum whistle. I use a very fast epoxy in a cartridge dispenser with mixing tip. It is incredibly easy. The epoxy sets up in about 3 minutes, full strength at 6 hours.

 

[Big_Red_Daddy]

Oops, I really messed this up. I thought I had some nice internal fillets since I poured in some thin slow epoxy and rotated all around. I poured the 2 part polyurethane foam and it bulged the body tube all around the fin slots. It's beyond saving. Lesson: make sure you have nice fillets before using expanding foam. Going to see if I can get replacement parts. Pretty much everything is gone except the nose cone and payload since those weren't involved here.

 

[blackjack2564]

I don't use foam on cardboard rockets for exact same reason you had. I bulged out airframe. And the exterior fillets were in place. Had to grind them off as part of repair described below.
Better off just injecting epoxy for internal fillets on forward split fin. Rear you can leave off CR for foam, I JUST WON'T RISK another foam fiasco on cardboard. I still use it on glass.

How I fixed mine
I cut off tube. pulled/sanded off foam, finished internal fillets. Bought just a new airframe, & using box cutter/x-acto [new blade] slit between fin sets and slots to rear of tube. Did NOT open slots all way to back of tube. Just slit between slot and rear.
Slid built motor mount and fins into new tube and slots. Bit tricky as you must "pull Up'' airframe to get slot around fins into slot.

Then slathered glue on rear CR's edges ..using large pipe clamp [5 bucks] clamped tube to CR. Not as bad as this sounds and saved the rocket for only cost of new slotted tube.

 

[dlb]

One Thing I did do and recommend, Glass the air-frame. I used some pretty mean stuff. But I expect this wolf to take a beating. I know it's a White Wolf, but mine ending up being the DarkSide of the WhiteWolf. Due to Argonia road rash I also glassed the front edge of the forward fins and put metal tape too boot for protection. (3) launches on her so far, Maiden( L910) at Airfest, video link is a K1000 in Camden,SC.



YES she Howls

 

[Big_Red_Daddy]

I don't use foam on cardboard rockets for exact same reason you had. I bulged out airframe. And the exterior fillets were in place. Had to grind them off as part of repair described below.
Better off just injecting epoxy for internal fillets on forward split fin. Rear you can leave off CR for foam, I JUST WON'T RISK another foam fiasco on cardboard. I still use it on glass.

How I fixed mine
I cut off tube. pulled/sanded off foam, finished internal fillets. Bought just a new airframe, & using box cutter/x-acto [new blade] slit between fin sets and slots to rear of tube. Did NOT open slots all way to back of tube. Just slit between slot and rear.
Slid built motor mount and fins into new tube and slots. Bit tricky as you must "pull Up'' airframe to get slot around fins into slot.

Then slathered glue on rear CR's edges ..using large pipe clamp [5 bucks] clamped tube to CR. Not as bad as this sounds and saved the rocket for only cost of new slotted tube.

Sorry to hear but good to know that I'm not the only one and there is a solution. I will explore this with LOC. I think I can make this work and save a lot of time I already put in.

 

[Big_Red_Daddy]

One Thing I did do and recommend, Glass the air-frame. I used some pretty mean stuff. But I expect this wolf to take a beating. I know it's a White Wolf, but mine ending up being the DarkSide of the WhiteWolf. Due to Argonia road rash I also glassed the front edge of the forward fins and put metal tape too boot for protection. (3) launches on her so far, Maiden( L910) at Airfest, video link is a K1000 in Camden,SC.



YES she Howls

Don, thank you for the advice and the video.
I was going to fiberglass the fins tip-to-tip since it's pretty easy to push this to mach with any M motor. I'm guessing you are hitting mach with higher thrust K and L motors but I'll run some sims.
When are you going to launch yours on an M?
Is glassing the leading edges of the fins enough to survive mach? Or does it need tip-to-tip?
I was thinking about using carbon fiber on the fins to stiffen them and that will give it a really nice look too.

 

[Theory]

Did you secure the aft centering ring prior to pouring the foam? If not, I do not see how enough pressure was created to affect the airframe.

I had planned to foam a future cardboard fin can between the bottom two CRs (I use 3 CRs on all my rockets). The aft ring would be left off allowing me to pour in the foam and then added once it expected and cured. This would allow excess (if any) to escape out the aft end)

Does this sound workable, or a poor idea?

 

[dlb]

Have I hit MACH? NO, but very close (.9mach)(L910)
I covered the leading edge for wind dragging the chute and rocket across the Airfest landscape or as CJ said Argonia Road Rash(ARR). Got that once before, Drag 1/2 mile in fresh plowed field, sanded the leading edges paint right off. So I tried 1" metal tape over thin glassing on the tip only, it worked!!!!

Tip to Tip is always a good practice , but I did not. That MACH crossover could be rough on the fins.
This year at Airfest/LDRS she taking a ride on an M650, but I do worry that she may hold at the mach threshold speed to long and the Fins could a beating. We shall see!!!

Carbon fiber is a overkill, glassing will answer your stiffening problem.

Just make sure to leave flat surfaces between the fins, shape edge flats are better. That's were the whistle comes from.

There's no stupid questions, but many stupid answers!

 

[Big_Red_Daddy]

Have I hit MACH? NO, but very close (.9mach)(L910)
I covered the leading edge for wind dragging the chute and rocket across the Airfest landscape or as CJ said Argonia Road Rash(ARR). Got that once before, Drag 1/2 mile in fresh plowed field, sanded the leading edges paint right off. So I tried 1" metal tape over thin glassing on the tip only, it worked!!!!

Tip to Tip is always a good practice , but I did not. That MACH crossover could be rough on the fins.
This year at Airfest/LDRS she taking a ride on an M650, but I do worry that she may hold at the mach threshold speed to long and the Fins could a beating. We shall see!!!

Carbon fiber is a overkill, glassing will answer your stiffening problem.

Just make sure to leave flat surfaces between the fins, shape edge flats are better. That's were the whistle comes from.

There's no stupid questions, but many stupid answers!

Snow Ranch is pretty soft but I could launch this at a Tripoli plowed field launch (TCC where LDRS was in 2018), or BALLS.
M650W is my dream motor with 11.5s burn and tons of white smoke. Please post lots of videos.
My sim on M650W says 766mph and 14k feet. So my sim indicates holding at mach like you suggested. But you could punch it through on an M1550R (10,750') and hit 902mph!

I'm just thinking carbon fiber to have a nice look on the fins but I know it is overkill.