Looking at level 2

I plan to use a Loki 54mm case for my level 2 attempt. I was looking at 38mm for my level 2 but there were several people who chimed in and said 54mm would be better. Ok, I'm thinking the J820 motor.

Here's my question. At what point do you need to fiberglass paper tubes? I was looking at the Binder Excel dual deploy but will it handle a J without glassing? I was also thinking about building heavier by using blue tube. It looks like J's will put 9lbs rockets close to a mile up. Do I really need to be concerned about a J motor in a 6.5 lbs paper rocket? I build well.

For my L2 I used a J381 Skidmark in an all cardboard and plywood Madcow Super DX3. I haven't had any issues with using larger motors in cardboard rockets. Look around here and you'll see lots of examples of K, L, and M motors in cardboard rockets as well.

That being said, fiberglass offers many advantages and disadvantages. It is heavy, but darn near indestructible on reentry. I've had plywood fins chip, and cardboard start to buckle with continuous ejection charges (though I tend to pack mine big), but you don't often have these problems with glass.

Squawsach said:

I plan to use a Loki 54mm case for my level 2 attempt. I was looking at 38mm for my level 2 but there were several people who chimed in and said 54mm would be better. Ok, I'm thinking the J820 motor.

Here's my question. At what point do you need to fiberglass paper tubes? I was looking at the Binder Excel dual deploy but will it handle a J without glassing? I was also thinking about building heavier by using blue tube. It looks like J's will put 9lbs rockets close to a mile up. Do I really need to be concerned about a J motor in a 6.5 lbs paper rocket? I build well.

Click to expand...

On the web site it says it is H to K capable. If you have question contact Mike Fisher at Binder Designs ([email protected]), I am sure he can give you any tips he thinks you will need.

You do not need to worry about glassing an Excel Plus. That was my L2 rocket! I built mine from the stock components using nothing but standard hobby epoxy, with no strengthening modifications at all.
It has flown on everything from a 38mm J350W, to a longburn K270W, to high-thrust research K motors. A K550W took mine to 7K and the K270W took it to 9K.

AlnessW said:

You do not need to worry about glassing an Excel Plus. That was my L2 rocket! I built mine from the stock components using nothing but standard hobby epoxy, with no strengthening modifications at all.
It has flown on everything from a 38mm J350W, to a longburn K270W, to high-thrust research K motors. A K550W took mine to 7K and the K270W took it to 9K.

Click to expand...

I can validate all of Wilson's claims. I've seen most of those flights (and I have my own Excel that is also NOT fiberglassed).

Squawsach said:

At what point do you need to fiberglass paper tubes?

Click to expand...

"Need" can't be answered easily; it's unlikely that the tube itself will fail during the thrust phase, at any velocity you'll attain with L2 motors. The primary benefit of fiberglassing paper tubes is a smooth and durable surface.

A common mistake is to think of durability only during thrust. Landing and transportation are much more likely to damage a well-built rocket than flight.

Here are some more important things to be concerned with:

• poorly bonded fins/centering rings causing shred at max Q
• too long/short a motor delay causing a zipper
• too small a parachute causing a broken fin on landing
• no pressure relief hole causing the nose to come off during coast

Good luck on your cert flight!

chuck5395 said:

I can validate all of Wilson's claims. I've seen most of those flights (and I have my own Excel that is also NOT fiberglassed).

Click to expand...

Why thank you! Yep, last time she flew was at Rocketober on that awesome EX K800 motor to about 7,000'.

Squawsach said:

I was looking at the Binder Excel dual deploy but will it handle a J without glassing?

Click to expand...

FWIW, I've seen one fly on an L motor that was built with wood glue. They fly on K's every weekend. Yeah, it will handle your wimpy J motor. if you do a good airfoil job on this with a nice smooth paint job and clean fillets you can expect a J350 to get this rocket near 5K', and a J570 gets it to near 7K' on a calm day.

A fiberglass rocket will do about half that altitude. You can save a bit of weight by using titebond II wood glue for all wood and paper bonding. It is all I've been using on these for the past ten years or so and I've found it to be stronger than epoxy for these materials.

Binder Design said:

A fiberglass rocket will do about half that altitude. You can save a bit of weight by using titebond II wood glue for all wood and paper bonding. It is all I've been using on these for the past ten years or so and I've found it to be stronger than epoxy for these materials.

Click to expand...

Makes sense considering Titebond is stronger than wood/paper.

AlnessW said:

Makes sense considering Titebond is stronger than wood/paper.

Click to expand...

I'm thinking I'll build my NXRS rocket this way.

chuck5395 said:

I'm thinking I'll build my NXRS rocket this way.

Click to expand...

Good idea! Are you doing the Max Q challenge as well?

AlnessW said:

Good idea! Are you doing the Max Q challenge as well?

Click to expand...

Let me put it this way, if everyone else shreds their rocket, I'll win.

chuck5395 said:

Let me put it this way, if everyone else shreds their rocket, I'll win.

Click to expand...

Hahaha! Sounds good.