Unreinforced phenolic vs cardboard?

I'm in the planning stages for my next HPR build. Originally I was just looking at getting another kit but I've decided I'd like to scratch build instead.

The rocket I'm planning would probably be 3" in diameter with a 38 or 54mm motor mount.

I'm currently considering using unreinforced PML Phenolic for the airframe. As I understand it, it is very strong in flight but can be quite susceptible to landing damage. My question is: is it any more susceptible to landing damage then regular HPR cardboard airframes? I understand that cardboard will buckle and phenolic will crack/shatter and my question is not which one will be easier to fix. I'd like to know If it'll take more force to damage phenolic then cardboard upon landing (or vise versa).

I usually land on soft surfaces such as bush and/or grass etc.

I should also note that the main reason I'm considering using phenolic is because of cost. It's the cheapest airframe besides cardboard and unlike most airframes, it's readily available in Canada, so If I use it I won't have to get it from the US and pay ridiculously high shipping charges.

The only issues I had with phenolic were zippers (before I fixed that), and a case of water damage. I would not bring it down as fast as a fiberglass airframe so a good size chute is recommended.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

markkoelsch said:

The only issues I had with phenolic were zippers (before I fixed that), and a case of water damage. I would not bring it down as fast as a fiberglass airframe so a good size chute is recommended.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

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Phenolic is better than cardboard for water damage though. You can get it wet without caring, though I wouldn't go so far as submersion.

Agreed, phenolic is better than cardboard as far as water resistance.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

I witnessed a phenolic rocket that was set upright on its tail and was then blown over by a wind gust. The rocket had a 3 inch chip break off the end of the tube from this little fall to bare ground (no rocks). So, yes it can be very brittle.

As far as durability, I recommend glassing. It does not matter if the base frame is cardboard or phenolic. I now glass all my airframes. I personally consider glassed phenolic to be the greatest strength for the money and effort required. See my statistics below:

HPR Level 3
9 yrs of flying
304 HPR flights
15 rockets

8 of 10 glassed rockets are still flying
1 of 5 un-glassed rockets are still flying

Avg number of flights on un-glassed rockets: 16
Avg number of flights on glassed rockets: 22.4

I have one rocket that is glassed phenolic with over 70 HPR flights.

Sparky

Bryan Sparkman
Tripoli #12111, L3
NAR #85720, L3

I've never glassed a rocket, and used PML phenolic tubes on many. Over the last 15 years, some have had damage, but that was due to other things that glassing wouldn't have helped.. (such as a Cato or a lawn dart from 4k) And all but a couple were repaired and flew again...

Also you can look into flex able phenolic (I should have it in inventory in a week or so). Stronger then paper but has some give so it won't crack like regular phenalic.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

Where cardboard can dent, phenolic can shatter. Cardboard also wears more, and will sometimes "pill" at separation points. There is no perfect "one size fits all" airframe.

In my experience, PML phenolic is pretty durable. Unlike cardboard, it does require the use of epoxy, as the phenolic resin keeps the wood glue from penetrating.

-Kevin

bob jablonski said:

Also you can look into flex able phenolic (I should have it in inventory in a week or so). Stronger then paper but has some give so it won't crack like regular phenalic.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

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I built a Yank Iris that was 4" flexible phenolic. I got lazy and just built that sucker. I was gonna glass it, but as I said... So, away I went. It's flown many times, and so far no problems with airframe damage even after a tangled chute at MWP one year.

Adrian

Just got the Phlexable Phenolic in from 1.145 to 3.9 plus payload sections. all up on the website now.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

Why not just use “Blue Tube”?

boomtube-mk2 said:

Why not just use “Blue Tube”?

Click to expand...

Because they can warp lol.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

SinfulDarkLord said:

Because they can warp lol.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

Click to expand...

Early ones did but the current ones don't. There is also Giant Leaps Magna-Frame, a gray version of Blue Tube.

Sailorbill said:

Early ones did but the current ones don't. There is also Giant Leaps Magna-Frame, a gray version of Blue Tube.

Click to expand...

When I got a blue tube directly from ARR. I recieved a defective tube. I was not very happy as David blamed it on the warping. That tells me even version 2.0 can still warp. It hardly warps, but still does.

Magnaframe is my favorite due to having phenolic along in the tube. It keeps the tube from warping and you get the advantage of heat insulation.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet