Reinforcing balsa fins

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Is there a way to reinforce balsa fins to make them as strong as plywood? Do you think covering the fins in epoxy would make them stronger?
I have 1/8 balsa fins that came with a kit that's meant to handle E & F motors. I was wondering if I could get them to withstand a fast motor like a G125T?

I hope you all had a Merry Christmas!



Thanks,
 
You can add the self adhesive laminating paper to them and that will eliminate filling required and make them much stronger. What is the kit? You should sim it to see what velocities you expect and that will be helpful to see what you need to do.
 
Is there a way to reinforce balsa fins to make them as strong as plywood? Do you think covering the fins in epoxy would make them stronger?
I have 1/8 balsa fins that came with a kit that's meant to handle E & F motors. I was wondering if I could get them to withstand a fast motor like a G125T?

I hope you all had a Merry Christmas!



Thanks,

I think epoxy by itself will add more weight with just a little strengthening. Some things I have done on various builds:

Paper the fins with regular printer paper and white glue. K'tesh and others have many posts here on their techniques.

Old school tissue and dope covering. Takes a little more work to fill and finish than the paper method.

Hardwood strips added to the leading and trailing edges.

Do-it-yourself ply by adding 1/64 or 1/32 plywood skins using white glue.


Of course, with a hot-rod motor, your root edge to airframe bond will be extremely important as well. Are you building a kit ?
 
You can add the self adhesive laminating paper to them and that will eliminate filling required and make them much stronger. What is the kit? You should sim it to see what velocities you expect and that will be helpful to see what you need to do.

The Dynastar "Aerodactyl TS". I plan on adding one of the stages to a different rocket I have, and fly it on a G125 to a F20.



Thanks,
 
That kit sims to almost 800 ft/s on a G125. I'll let some other guys who have more experience with balsa advise on if it will survive. As samb said its not just the balsa, but you need a good root bond, maybe do 'glue rivets'.
 
Nice. That's a newer model I think so I don't know if you'll get much hands-on advice on it yet. The instructions do show a fin papering method:

https://www.apogeerockets.com/downloads/instructions/31105-AeroDactyl-Instructs-Web.pdf


"... designed around the Estes 29mm diameter rocket engines. These engines are low thrust, and therefore need a low weight rocket for maximum speed performance."

I might send a note to Apogee asking if they did any test flights with AP motors.
 
Nice. That's a newer model I think so I don't know if you'll get much hands-on advice on it yet. The instructions do show a fin papering method:

https://www.apogeerockets.com/downloads/instructions/31105-AeroDactyl-Instructs-Web.pdf


"... designed around the Estes 29mm diameter rocket engines. These engines are low thrust, and therefore need a low weight rocket for maximum speed performance."

I might send a note to Apogee asking if they did any test flights with AP motors.

I contacted Apogee. They said they never did a composite motor 2 stage flight with electronics. They said as long as I reinforce the fins, and have a dual deploy rocket, I could give it a go.



Thanks,
 
I contacted Apogee. They said they never did a composite motor 2 stage flight with electronics. They said as long as I reinforce the fins, and have a dual deploy rocket, I could give it a go.



Thanks,

"To infinite and beyond !" I think those of us familiar with your posting history here assumed you would give it a go. :) Apogee gives you a nice "leg-up" with the Rocksim file available for download. Yep, electronics are needed for composite staging. Has your brother done that yet ? (full disclosure, I haven't yet). Good Luck, Stay Safe.
 
"To infinite and beyond !" I think those of us familiar with your posting history here assumed you would give it a go. :) Apogee gives you a nice "leg-up" with the Rocksim file available for download. Yep, electronics are needed for composite staging. Has your brother done that yet ? (full disclosure, I haven't yet). Good Luck, Stay Safe.

Nope, never done electronic staging before. BUT, this is NOT a HPR rocket, it's a MPR rocket. I have a Eggtimer that I can use for the staging.
The G125T will boost it up pretty good, and the F20 will just keep it going.. Slowly... I need to do lots of simulations and tests before doing this flight.



Thanks,
 
Nope, never done electronic staging before. BUT, this is NOT a HPR rocket, ...


Thanks,

Wellllll... G125T > 80N average thrust means it's HPR at NAR or Tripoli launches in the USA. It is MPR as designed with Estes BP motors.
 
Wellllll... G125T > 80N average thrust means it's HPR at NAR or Tripoli launches in the USA. It is MPR as designed with Estes BP motors.

OK, how about G77R to a F20W. That is MPR in the eyes of NAR & TRA.




Thanks,
 
You are passing the 62.5g propellant mass with these two - 88.1g I believe

You should be able to do it once you get your JR Lvl 1 though
 
About the original question, papered balsa is pretty darn strong. I use a simple method with wood glue- "paint" the fin with glue, stick on a piece of paper, compress it overnight, then cut it out with an Xacto knife. Repeat on both sides. It takes a bit of sanding to get the edges nice but it's rock solid once it's done.

Sent from my LGL44VL using Tapatalk
 
Yeah, that paper technique works very well. And as said above, sand it REALLY well!
Not sure if this is a good idea, that's why I'm checking in here, but can you:
Fly a 2 stage rocket using a F15-4 in the booster and a F15-6 in the sustainer? I know people use the F15-0 motors, but you could do it differently?




Ben
 
Yeah, that paper technique works very well. And as said above, sand it REALLY well!
Not sure if this is a good idea, that's why I'm checking in here, but can you:
Fly a 2 stage rocket using a F15-4 in the booster and a F15-6 in the sustainer? I know people use the F15-0 motors, but you could do it differently?




Ben
You would only do that if you were igniting your upper stage electrically and using motor eject to deploy a parachute, at which point you're much better off putting a high thrust composite like an F27 or F42 there, or one of the 70-80 newton G's.

That does bring up an important point- how are you planning to light that F20? I would recommend a CTI 1 grain 29mm F instead to get a bit more reliability- they have small BP pellets that make them very easy to light. I know you have a 3G case- can you get your hands on a couple spacers?

Sent from my LGL44VL using Tapatalk
 
Shape the fin, or not, and use thin CA glue squeegeed in to the grain. Definitely have to do it outside in the open air and with gloves. I've done that countless times to "harden" the leading edge of high speed RC airplanes or to reinforce threaded basswood and balsa attach points. Wicks in pretty good without a squeegee. Or you can cut a second set of fins with the grain oriented 90 degrees to the originals and glue them together. I use a piece of sheetmetal under them and lay magnets on top for pressure. Printer paper has a grain too that corresponds to the 2nd number, 8x11, the grain runs the length of the paper. Does it matter compared to the surface contact area the paper provides? Don't know. Haven't seen anyone post a catastrophic fin fail just due to flight stress
 
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