Wildman Sandhawk and L2 possibilities.

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I emailed Wildman. It's been eight days and I have no idea on the status of the order, lol. Been to busy to care lately.
 
Parts of orders weren't in stock and the other issue is the website screwed up shipping charges. I don't fault him. It took a lot of his effort to swap websites and I know the order was porked when the DMS didn't have a HAZ charge.
 
So here's an idea I got kickin' around on a Terrier Booster. I might 3D model it this weekend for giggles. I can't do anything with it until I get L-1/L-2 signed off. The terrier with a 4" airframe tube could hold up to a 75mm or 98mm casing. Stuff I don't even have certs to fly, lol. Right now I'm trying to keep it simple, scalable, stage-able, and adaptable. And this would be more of a real long term plan with what to do with a Sandhawk kit eventually and likely after graduation.
ZA4rmIf.jpg

Heard there was a Terrier Sandhawk.
 
For the Terrier Booster I'm thinking about a 30" section at $58.
https://www.madcowrocketry.com/4-inch-g12-airframe/

Two G10 3/32" Sheets at $15 each for four fins.
https://www.madcowrocketry.com/3-32-g10-fr4-plate/

It looks like whoever was beating me on the Nike-apache kit was right. Didn't make the $70 goal. Hah.

Then centering rings, transition 3D print, airframe tube 38mm, jigs ,and other stuff.
I still don't have a rocket to put on it yet. The other issue Mark brought up was don't rip the fins off of the Sandhawk.
 
Erm...

Well here is the kit as of 2017-2018.
QsD0Pmn.jpg


I understand the motor mount is the smaller diameter tube. There's a coupler inside the airframe body tube, and I have a feeling I could connect the other short airframe tube to extended airframe length.
No instruction manual.
 
Looks like all of the standard DD rocket pieces are there, is there a question or something you think is missing?

The avionics bay coupler is the one sitting inside the aiframe, I can see it blocking the upper half of the fin slots. The very short (~1") airframe piece is the vent band for the avionics bay.

Still waiting to hear about my BS order, but it's mostly AT motors so I'm sure there are still shipments coming in.
 
Erm...

Well here is the kit as of 2017-2018.
QsD0Pmn.jpg


I understand the motor mount is the smaller diameter tube. There's a coupler inside the airframe body tube, and I have a feeling I could connect the other short airframe tube to extended airframe length.
No instruction manual.

So here’s the deal. Once you get to this type of rocket the assumption is that you’ve done a few successful smaller rockets. The pieces go together the same way. If you haven’t done any, I suggest you look at the instructions that Public Missiles have on their website or even better search through the many build threads by Crazy Jim (Blackjack2654) here on TRF, or at the vast amount of useful information on John Coker’s website.


Steve Shannon
 
Nothing missing. I just haven't used a DD system before and it perplexed me upon sight.

You should get a text when it shipswith tracking link, a text when it is out for delivery, and another text upon arrival a few minutes after the doorbell rings.
 
I've done the RB-05A from Wildman which I need to fix the fillets on. I don't plan on flying sandhawk soon. I will snoop around for links on TRF or ask about DD setups. The similarity ends with the bulkhead and MMT system between the smaller rocket and this one.
 
glda6eq.jpg


So something like this?
Nosecone
Airframe extension
G12 airframe coupler/avionics bay/Bulkheads
Vent band
Airframe tube
Motor Mount/Fins/centering rings
 
I've got the kit into OR. My recovery gear masses aren't exact yet. The thing predicts Mach 1.43 on a Loki 38-1200, K1127. AeroFinSim v4.53 Claims it flutters at Mach 0.76 at G10 fiberglass. The fin span is nearly 4.04". I believe the fin span is too much for that motor. Also if the fins were solid CF they would survive Mach 1.07. I don't know if this will be like Madcow DX3 or whatnot that has a low flutter predict and no actual flutter or not. I try to err on side of caution and may need to trim fin span. It seems to handle an I class motor on stock fin geometry. The J's and K's seem a tad tough on it, but the airframe supports those casing lengths.
 
UHWhhAc.jpg

Flutter Naca 4197TN reference to body tube.
EIbtMgA.jpg

If anyone wants to check the fin profile inputs.
EM1qYUO.jpg

It seems to do fine on bending stress analysis with Rocketpoxy G5000. I just want people to realize what the stock fin geometry can handle motor wise may not equal the volumetric capacity on paper.
Granted this was a "Scale" model and I'm not trashing Wildman's product. This is just what theoretically the FinSim program stacks up against slapping the biggest coolest motor into it.
 
IPKawEn.jpg

This is my initial OR file, granted it will only get heavier and slower with mass additions for electronics, nose/chute overrides, and etc. I think the manufacturer fin design is well within reason for a dual deploy rocket. It's not super sketch like other brands. This is a depending how big of a motor you want to shove it into it expect to modify it.
If you shed an inch off the stock fin span the flutter mach will increase to Mach 1.29.

This is a first of several fin modifications below to increase flutter mach for J and hopefully later, even K motors.

This has fin span 3" with tip length 5.1875" after trimming fin tip with fin sweep of 5.23" for 60.2 degree fin angle.
Get me a few moments to update more finsim files.
rhb3gXs.jpg

This is the profile of fin modification 0.
xBdgu3E.jpg

5PHJzPN.jpg

Corrections applied.
 
In order to fine tune the iterations, I needed a more accurate stability caliber measurement. Therefore the actual component masses were measured for nosecone, short body tube, shortest body tube, long body tube, and motor mount were measured. The rocket is more stable than initial assumptions. Therefore more fin span can be trimmed.
Nosecone 120g
Short BT: 185g
Shortest BT (inner tube coupler):45g
Long BT 365g
MMT:65g
This is still neglecting avionics, wadding, accurate chute masses, additional hardware, and actual fin mass for an equal comparison between modified and unmodified states.
e7hihvG.jpg

OR stock updated masses.
wDRTXBV.jpg

OR mod 0 updated masses.
 
OR Mod 1, flutter resistance mod for L-2 motors to Wildman Sandhawk.
xtCrgUE.jpg

And.
5L3rJzQ.jpg

Mod 1 Fin conversion to fly Loki 38-1200, K1127 no fins rip off. Stability should increase with heavier than simulated recovery and avionics devices override.
 
I was gonna say nice aerobee 150 you got there , but I know its a sandhawk. Why mess with the fins ? You can easily make it handle any 38mm motor on the market without chopping up the fins.

Eric
 
I think it could take a baby J motor once on stock fin profile. I don't feel confident in the large fin span surviving Mach 1.5 or K loads repeatedly by what FinSim claims using NACA4197TN. I don't want to be liable for fin flutter related fin failures when I can modify fin geometry to avoid the flutter. It won't be a Sandhawk anymore, lol.

I would feel different about this if multiple posters had flight data to Mach 1.5-2 and no fin failures.
 
How many times do you plan to fly it on a 38/1200 load? Instead of chopping it up , why dont you simply replace the fins with something thicker or even carbon fiber? You can use the stock fins , laminate them , install them , then t2t them. You could build it without a motor mount and fly it on a L with the stock fins .
 
Or fly it within it's limits. Why push it to 'plaid' speeds? keep it as the scale it it is..

(Why do you seemingly always need to push a rocket to +2MACH?!)
 
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