Rookie's scratch build

[Willie]

Three fins closer. The design is looking leviathan like. Oh well.

 

[himitsu]

Three fins closer. The design is looking leviathan like. Oh well.

It looks great!

FWIW rocketeers normally use plywood with an odd number of plys, and orient the grain of the outer layers to run parallel to the leading edge (and not the root edge). This convention goes back to building rockets with solid balsa wood fins, where following proper grain orientation determines whether or not your rocket gets to preserve its fins during flight. Having said that, I know from your previous post that you're using 4-ply plywood, and quite frankly, because it's plywood, I think your fins will probably do fine, as is.

 

[himitsu]

BTW, your plywood looks kinda dark. It could be the lighting, but what kind of wood is that?

 

[Willie]

When things go wrong, build another

 

[Willie]

It looks great! FWIW rocketeers normally use plywood with an odd number of plys, and orient the grain of the outer layers to run parallel to the leading edge (and not the root edge). This convention goes back to building rockets with solid balsa wood fins, where following proper grain orientation determines whether or not your rocket gets to preserve its fins during flight. Having said that, I know from your previous post that you're using 4-ply plywood, and quite frankly, because it's plywood, I think your fins will probably do fine, as is.

I believe it is birch. It must be three ply because the grains are parallel on each side.

 

[himitsu]

When things go wrong, build another

oh no! What happened?

 

[himitsu]

I believe it is birch. It must be three ply because the grains are parallel on each side.

Hmmm. With 3-ply, two thirds of the grain will run parallel to the root edge. That's questionable. I would cut again, and orient the grain to run parallel with the leading edge. Sorry.

 

[Willie]

It looks great!

FWIW rocketeers normally use plywood with an odd number of plys, and orient the grain of the outer layers to run parallel to the leading edge (and not the root edge). This convention goes back to building rockets with solid balsa wood fins, where following proper grain orientation determines whether or not your rocket gets to preserve its fins during flight. Having said that, I know from your previous post that you're using 4-ply plywood, and quite frankly, because it's plywood, I think your fins will probably do fine, as is.

I should know better about the grain orientation. Thanks for catching! They will be re-cut. I stick with the mantra, "When things go wrong, build another."

BTW, what does the initials FWIW stand for?

 

[Willie]

oh no! What happened?

I was at 12 oz total Nose Cone weights. I thought I could trim a little more (make it fly higher, and I didn't need the weight for stability). The drill bit caught the knot in the wood and boom, I got a two peice nose cone.

I took more time on the second turning, and used some of the technics I learned from the forum. The second turning is better, but it weighs 16 oz.

 

[JohnCoker]

I believe it is birch. It must be three ply because the grains are parallel on each side.

If it's three-ply, then it's not "birch" plywood. Baltic birch plywood refers to high number of plies hardwood plywood. In addition to the higher number of plies, "birch" plywood has more carefully selected wood without voids. It also comes in metric thicknesses (3, 6, 9, 12mm).
https://www3.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=&FVSEARCH=baltic+birch+plywood&search=Go

Given the dark color and that you say it's 3-ply, I'd guess you have "hardwood lumber core" plywood (thick core, two thin veneer layers).

• birch: highest number of plies, no voids, perfect surface
• lumber core: 3 plies, no voids, perfect surface
• construction: lower number of plies, has voids, varying surface (A/C)

Birch plywood is generally what is used in hobby rockets, although I'm sure some of the larger rockets have been built with construction plywood (¾" AC, etc). For this size rocket, I'd think 6mm birch ply would be ideal.

 

[himitsu]

BTW, what does the initials FWIW stand for?

Internet jargon: FWIW = For what it's worth; For whoever is wondering; From what I've witnessed (the first is the most popular)

You can discover the meaning of various abbreviations through Google. For example, to see the above definition, just Google on: FWIW meaning

Of course, you can always ask.

 

[himitsu]

I was at 12 oz total Nose Cone weights. I thought I could trim a little more (make it fly higher, and I didn't need the weight for stability). The drill bit caught the knot in the wood and boom, I got a two peice nose cone.

I took more time on the second turning, and used some of the technics I learned from the forum. The second turning is better, but it weighs 16 oz.

Ah. Well, your persistence will certainly pay off, I'm sure. Plus, that second cone looks really good, too.

 

[Willie]

I trimmed the second noce cone down to 12 oz. I could go lower, and gain some height without compromising stability, but after lossing 1 nose cone, I want to hold on to the 2nd one. 12 oz it will be.

I am committed to a 29mm Motor Mount after cutting the tube to 26". A H70 will go 2300", with a 1.48 Cal. A G80 will go 1200" with a 1.69 Cal.

Now, tomorrow I will save for recutting the fins I initially cut on the wrong grain axis...

 

[himitsu]

Sounds good. This is a cool project, scratch building your L1 cert airframe out of stuff you've collected. Few go this route. So, when successful, you will join a small illustrious crowd. You clearly enjoy building things; however, don't neglect to launch your previous scratch built creations. Get some "air time" before you complete this project, and a feel for how well your rockets can handle the stresses of flight (and recovery—required to get your L1).

 

[Willie]

Given the dark color and that you say it's 3-ply, I'd guess you have "hardwood lumber core" plywood (thick core, two thin veneer layers).

I confirmed that it is indeed a hardwood core plywood (3 ply with two veneers).

 

[Willie]

Three hardwood 3 ply plywood fins recut. The grain now is parallel to the leading edge.

I hope this will work. Any input welcome!

 

[himitsu]

Look'n good (the three on the left).

 

[Cl(VII)]

Very nice looking fins. You going to have this ready for the December high power launch?

 

[Willie]

Very nice looking fins. You going to have this ready for the December high power launch?

I am hoping between my schedule, and the weather, I can get out there and make an L1 certification attempt. I have a Wildman Jr built and ready. I don't have a HPR motor, nor am I sure what the steps are to making a L1 cert attempt. This build will likely be built, but nude, by the December HPR Launch.

I wanted to bring the Wildman Jr. to a local DARS MPR launch in Frisco to have some folks do a review prior to shoving a motor in the backend. It would make me feel better to have someone with actual HPR experience review my setup. I did that build using searches here for details on the recovery setup.

 

[Willie]

Fin profile. Rounded leading edge, tapered trailing edge.

 

[Cl(VII)]

I am hoping between my schedule, and the weather, I can get out there and make an L1 certification attempt. I have a Wildman Jr built and ready. I don't have a HPR motor, nor am I sure what the steps are to making a L1 cert attempt. This build will likely be built, but nude, by the December HPR Launch.

I wanted to bring the Wildman Jr. to a local DARS MPR launch in Frisco to have some folks do a review prior to shoving a motor in the backend. It would make me feel better to have someone with actual HPR experience review my setup. I did that build using searches here for details on the recovery setup.

You can go to the buisness meeting on the first saturday of the month, I am sure you will find some knowledgeable folks there. I too am planning to attempt an L1 cert at that Dec launch. If you're going to give it a shot then, you will probably need to get your motor and hardware ordered soon. Other than having the equipment, you fill out the form linked to below, show up at the field and tell Jack, Suzy, Sam, etc. that you want to make a certification attempt and they'll help you out. The only note is tha you will need to build the motor at the field with someone watching, so get acquainted with the method. You will also need to have your certification motor delivered to someone with an L1 certification already, I had mine delieved to Jack and Suzy.

Form: https://www.nar.org/pdf/hpappl.pdf

 

[Willie]

lots of progress today. motor mount assembled and epoxied into tube. fins in and epoxy fillets done. motor retainer on.

still need the hardware for the nose cone, and a bulkhead that fits. thinking about all-thread for retaining the bulkhead.

currently 27 oz without a parachute, or paint....

 

[Willie]

Attached 550 para cord to the harness, and attached a 30" parachute to the para cord. Para cord length 4.5x the sustainer.

READY TO FLY.

Paint will have to wait till spring.

 

[TopRamen]

She looks good!:clap:

 

[XrayLizard]

Hope to see you at the Dec. launch. Everyone there will be very helpful !

 

[Willie]

Hope to see you at the Dec. launch. Everyone there will be very helpful !

I want to make one of the two launches. I have some rockets dying for a maiden flight.

 

[Willie]

No DARS launch again!! I am getting depressed. Might cheer myself up with some kit builds.

The problem is I just ordered them last night.

 

[Willie]

My baby flew today at the DARS launch. I believe I launched 4 rocket on their maiden flights today, all but one was a success. This one flew on a G80 and was beautiful.

 

[accooper]

OK, stupid question. Where can someone from San Antonio, Texas find 3/16 inch plywood? I cannot find it here!

Andrew

 

[Willie]

This rocket was made with luan plywood from Lowe's. I've since switched to Baltic birch plywood that I get from hobby town USA, or Woodcraft stores. The Baltic birch is significantly better plywood, so go with it, if you can.