Is this even repairable (massive damage)? Suggestions please.

The Rocketry Forum

Help Support The Rocketry Forum:

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
Not sure how I'd repair this, being as the strakes are such an integral part of the rocket... a defective Quest C12-4 that didn't fire an ejection charge caused a high speed lawndart. Suggestions as to how to replace the strakes and get it flying again?

Rocket destroyed by malfunctioning C12-4.JPG
 

David Schwantz

Well-Known Member
TRF Supporter
Joined
Jul 23, 2018
Messages
2,617
Reaction score
1,493
Location
MN
Cut off the damage at the lowest point. Get a coupler to add a new body tube section the same length you cut off. Make sure all is square. Make new strakes, again just the part you cut off. Install new tube, glue on strakes so they align. Prime and paint new section. May see just a small parting line, depending on how square you got the cut.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
I think I can manage that, though it nearly certain I won't be able to hide the join lines, etc. This rocket has already suffered several incidents with fin damage (those long finger-like fin tips love to snag on shockcord and parachute lines...

Thanks. I'll report back how its going.
 

Kelly

Usually remembers to get the pointy end up
Joined
Apr 26, 2010
Messages
651
Reaction score
580
Location
Oregon
The strakes at that point aren't really under any significant stress, so yeah just cut them off square just below the damage and replace with small pieces of balsa. Same with the tube.
 

David Schwantz

Well-Known Member
TRF Supporter
Joined
Jul 23, 2018
Messages
2,617
Reaction score
1,493
Location
MN
After she is all done and repaired, run a piece of 1/16" pin stripe tape over the joint lines. Shoot a bit of clear and you will never even see them.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
David, whoa, that is sure a big difference between the two photos. :)
 

David Schwantz

Well-Known Member
TRF Supporter
Joined
Jul 23, 2018
Messages
2,617
Reaction score
1,493
Location
MN
Well, built a new fin can. New one has G10 fins instead of ply. A bit heavier but way more durable, hope :)
 

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
9,438
Reaction score
4,140
Not sure how I'd repair this, being as the strakes are such an integral part of the rocket... a defective Quest C12-4 that didn't fire an ejection charge caused a high speed lawndart. Suggestions as to how to replace the strakes and get it flying again?

View attachment 487078
Strakes are cosmetic.

cut across rocket tailward of the lowest strake damage.

reshape all the strakes to taper or round to the cut point.

either go with slightly shorter rocket and add A bit of mass to the cone to bring CG forward,

does reduce your laundry space a touch.

alternative, do the same thing but substitute a length of body tube on the nose cone end, use a coupler as a shoulder.

Either will look a little different, but can still look good and fly well.
 

afadeev

Well-Known Member
TRF Supporter
Joined
Sep 21, 2017
Messages
1,935
Reaction score
1,148
The strakes at that point aren't really under any significant stress, so yeah just cut them off square just below the damage and replace with small pieces of balsa. Same with the tube.
If the strakes can be re-assembled into the original shape (e.g.: all pieces are present, just jig-saw puzzled out), then do as above.
If you can't re-assemble the strakes into the original shape, then either:
2). Cut them off and free-form new strakes shape, or turn them into long fins, or add dual-fin setup by gluing "canard" fins onto the body tube area you will be replacing.
3). Rebuild the whole thing. New strakes along with everything else, other than the nose cone.
4). Retire the old rocket, build and fly the next one.

Well, built a new fin can. New one has G10 fins instead of ply. A bit heavier but way more durable, hope :)
Those G10 fins will out-live the rocket!
I've rebuild a few mid-/high-power rockets that had G10 fins, re-using just the fins and the nose-cones. Everything else in the middle got unplanned "upgrades", due to various flavors or recovery malfunctions.

a
 

Bowman

Well-Known Member
Joined
Mar 8, 2014
Messages
325
Reaction score
224
Not sure how I'd repair this, being as the strakes are such an integral part of the rocket... a defective Quest C12-4 that didn't fire an ejection charge caused a high speed lawndart. Suggestions as to how to replace the strakes and get it flying again?

View attachment 487078
With some surgical precision you can probably save that top (pic) and perhaps other strakes in-place and only cut out the damaged portions of the others and the body tube. Using a razor blade to shave the strake free of the body tube down to where you want to splice new tube in, then splicing in a new section of BT. That would allow the strakes that are still intact to continue to be part of the structure.
Definitely salvageable.
 

jqavins

Gone beardless since then
TRF Supporter
Joined
Sep 29, 2011
Messages
6,734
Reaction score
3,532
Location
Howard, NY
Cut off the damage at the lowest point. Get a coupler to add a new body tube section the same length you cut off. Make sure all is square. Make new strakes, again just the part you cut off. Install new tube, glue on strakes so they align. Prime and paint new section. May see just a small parting line, depending on how square you got the cut.
Almost exactly this. Don't obsess over a perfect joint between the intact strakes and the replacement tips; just make it a pretty good joint and leave the side surfaces slightly beveled on both parts. Remove a bit of the paint from the intact parts of the strakes so you can carry a new paint job across the joint. DO obsess over aligning them perfectly; use splints and binder clips to keep the new piece aligned perfectly with the old.

The bevels will leave grooves where the two pieces meet. Fill the grooves and sand. You should be able to get it like new, with no visible pantie line parting line at all.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
I'm going to work on this at some point. Thanks guys for the ideas. :)
 

Scotty Dog

Well-Known Member
Joined
Mar 2, 2010
Messages
7,444
Reaction score
275
Ouch! Ild like to see the rest of the story. ( rocket).
Nice pigment colors.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
The rocket is one that I scratchbuilt, called the Talon.

Colors are: Rustoleum Premium Automotive lacquer (matte blue), with Testors Purplicious as the purple.
DSC02417.JPG
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
It is a good flier; normally a really straight up flight. The issue is that frequently the parachute snags on those fin tip "fingers". :( But they really do make the rocket look a lot cooler, so I keep repairing/replacing them. :)
 

cbwho

Well-Known Member
Joined
Mar 20, 2019
Messages
300
Reaction score
146
Location
MN
I like the look of the futuristic rocket. But sometimes I'm happy to retire a rocket as that frees up space.

I'm also reminded that most full size rockets are one time use rockets!
 

KenECoyote

Well-Known Member
TRF Supporter
Joined
Mar 19, 2015
Messages
3,148
Reaction score
428
Beautiful! If repairing with new tube and coupler, make sure that you have the coupler below where the nose cone sits...I've almost been caught off guard by this and have read of others doing the same.
 

jqavins

Gone beardless since then
TRF Supporter
Joined
Sep 29, 2011
Messages
6,734
Reaction score
3,532
Location
Howard, NY
Another thing I don't recall having been mentioned is this: when I'm making a permanent junction of two tubes like this (for a repair or not) I like to place a piece of aluminum angle across the joint and secure it with two rubber bands on each side to assure the joint is dead straight.
 

Woody's Workshop

Well-Known Member
TRF Supporter
Joined
Aug 3, 2011
Messages
4,448
Reaction score
284
Location
Reed City, Michigan (Lower)
Very nice design! Colors are exceptional! Perhaps make the plans available, or offer the plans up for sale?

Not that my advice is worth anything, but I would undercut the strikes at about a 30 degree angle and fit the new pieces in the undercut.
For any filling needing done I would use Tamiya White Putty. I have 100% success over anything else I've tried for adhesion, fast drying, easy of sanding with zero shrinkage when exposed to ultraviolet rays and huge temperature swings. (Unlike that awful red lacquer based automotive stuff) Including the Squadron brand White Putty.
You can also leave glue squeeze out to dry and sand it, but it's tough not to get into the components around the glue when sanding it.
Please, post pics of the repaired jewel when repairs are completed and again after paint work.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
991
Reaction score
635
Very nice design! Colors are exceptional! Perhaps make the plans available, or offer the plans up for sale?

Please, post pics of the repaired jewel when repairs are completed and again after paint work.
I did a very sparse build thread, but I am posting a Rocksim file for anyone who wants to build this rocket. I never did make up actual plans per se.

It may be some time before I get the rocket repaired (realworld stuff is distracting me lately), but sure, I'll see if I can get some pics. :)
 

Attachments

Top