New Wildman 38mm BlackHawk prototype....first look !

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I'm resurrecting this thread.
Due to a resurgence in the Blackhawk 38:

There have been numerous questions asked about this kit, so I searched back & found this.
Lo & Behold I never finished it! [Here anyways....I did the main build on the Australian Rocketry Forum for my mates down under]

So tomorrow I'll get out my BH 38 take some more pictures, cipher through the ones I have & finish it up, hopefully answering many of your questions along the way.
It's been through hell & back with a good bit of info logged into my flight book.

One of my all time favorite rockets & hopefully soon to be one of yours. Hard to beat for 125 bucks!
It's survived many drag races,[including the infamous first Pyrate drag race] lost in a tree, lost in a field and run over by a tractor towing discs, re-finished & vinyled several times to boot.

So start thinking of any question/problems you may have & we'll solve them together!
 
Cool. I have been following the thread. I may have to suggest Bridgett start on this one without me.
 
Damn, I just finished mine. Can't wait to see how she compares. CJ, will you be talking about trackers? I sure hope so, I'm having a hard time figuring that out. I want to use a GPS tracker but don't think it's going to fit.
 
Cool. I'm in the middle of a scratch built 38mm project. It's my first minimum diameter, and will fly WAY higher than anything I've built so far. I'm looking forward to picking up a handy tip or two from this thread that may apply to my own. I'll be watching/following along.

s6
 
Damn, I just finished mine. Can't wait to see how she compares. CJ, will you be talking about trackers? I sure hope so, I'm having a hard time figuring that out. I want to use a GPS tracker but don't think it's going to fit.

Yes I will cover that. I don't have a GPS as of yet.[waiting for the MissleWorks version] but if you have the dimensions of what you wish to use, I'm sure we can figure it out in a simplistic manner.
 
Yes I will cover that. I don't have a GPS as of yet.[waiting for the MissleWorks version] but if you have the dimensions of what you wish to use, I'm sure we can figure it out in a simplistic manner.

I plan on waiting for the missleworks also, any idea when it might be available? I was hoping to go big at spring Red Glare so I'll need something. Before I heard about the missle works, I was thinking BRB 900.
Stoked to have you doing this thread. Your 3" Darkstar thread was great!!
 
I'm also just finishing mine, with a few mods,and will be interested in seeing you complete this thread.
I have a question that might have been answered already but I can't seem to find it. In Open Rocket
to get a good stability margin it seems that you have to add a lot of nose weight. Have you added
weight and how much?

Darrel
 
I'm also just finishing mine, with a few mods,and will be interested in seeing you complete this thread.
I have a question that might have been answered already but I can't seem to find it. In Open Rocket
to get a good stability margin it seems that you have to add a lot of nose weight. Have you added
weight and how much?

Darrel

NO nose weight needed. Nada...None for any motor. Mine has flown on 29mm 180 case motors [H-165..H-128] 29mm 240 motors [H-180 ..H-210..H-220] In 38mm loads in the 240 case....360...480....600....720 cases In CTI every case from 2grain to 6xl.

There are NO stability issues.

There may be issues with the particular sim file you have regarding the weights of individual components. Did you draw this file yourself...weighing the parts...or is it someone elses?

Before this is over I will find mine, or draw one that's accurate.
 
Using a [1in.diameter] section of PVC pipe for my tool to pull out fillets, I first use it as the guide for placement of masking tape.
If done correctly the edge of the tool will just hit edge of tape when smoothing the fillets, keeping all the excess on the tape where it can easily be removed.
Leaving little or none to be sanded when the tape is removed.

Lay the tool in the V-groove and mark where edge touches fin. Mark at rear and front of fin.

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Mark where tool edge hits tube. Mark at front and rear of tube.

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Lay tape ,butted to marks front to back. check alignment with tool and adjust tape. The closer to where the tool hits tube and fin, the less sanding will be needed to attain great fillets!

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Since I originally came up with this method 3yrs ago, I have refined it to using the PVC smoothing tool as the guide. Coat the edge with Magic Marker101_0127.jpg and rub back & forth leaving marks you place tape on. It will take several "coatings" & rubbing in the V-groove while "rolling" the PVC pipe section to accomplish good marks.DSCN0900.jpg
 
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I used 15 grams of resin to 3.5 of hardener for each set of fillets [2 fins] .
Spreading the gooey epoxy into the V-groove as best as I could.
I knew better, thinking I could beat the odds, but as you can see by looking at my hands, I should of used nitrile gloves.

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Level out the epoxy as best you can. Makes it easier to pull the fillet later.

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After dipping the tool in alcohol, smoothed the fillets. You can see they are pretty clean, all excess on the tape. I got a good close edge with no lip.

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Different views so you can get a better idea of the fillet radius I was trying to attain.

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After doing some research, discovered a paper study done by NASA somewhere stating the ideal radius for fillets was 4-6 % of the root length of the fin. That's why I use the 1in diam. tool.[ I stayed at a Holiday Inn last night, maybe I dreamt that!]

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They look much larger than they really are.

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Is there a Blackhawk 54 in the works...maybe? Something with a slotted tube for a little more adhesion surface area with the fins? Long enough to take a 54/2560 or 6XL case in the lower airframe?
 
Is there a Blackhawk 54 in the works...maybe? Something with a slotted tube for a little more adhesion surface area with the fins? Long enough to take a 54/2560 or 6XL case in the lower airframe?

Yes ... Wildman is currently working on "project X" in his "Area 51" Yes it will handle Loooong motors.

As my SpaceCowboy 54 brought some new technology to the hobbyist for the first time ever..... Wildman has been working quietly on his new 54mm minimum to plug the gap in the BlackHawk series. Needless to say "radical" barely describes this thing & takes it whole next step forward....scratch that.....leaps & bounds forward. I am VERY excited about this new concept borrowed from the Aero-Space industry. New production methods are in the works as well as some other secret sauce technologies for putting the beast together.

That's all I can say about it, so don't bother with the PM's, e-mails, or asking me at a launch....I won't even acknowledge or reply to any question....period

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Nose cone for holding stuff:

I'm leaving it open for a variety of uses, remember this rocket is "Carbonite" NOT Carbon Fiber, so it's transparent for radio signals.

Cut a small section of Kevlar off the supplied shock cord to make an attachment point loop on the nose cone.
Tacked it on both sides with CA. [ I used a ring supplied with AT single use motors that's glued on as a thrust ring.] Seen here from my old files used in an adapter application for a thrust ring also. It happens to fit perfectly inside the NC & lets you put a nice fillet around it holding shock cord loop in place100_9943.jpg If you don't have any laying around cut off a section of any 29mm tube.

Then cut small sections of cardboard tube to compress and hold the tails in place while applying your favorite epoxy.....JB weld. Just so happens the spacers will accept a section of 29mm tubing should i want to place a tracker or other electronics in the NC and have them removable.file.jpg

So when your done you can make a 29mm tube/av-bay/tracker bay that slides right into place!
 
Recovery gear Y-harness:
Some of you may forgo this and use a threaded plugged closure with an eye-bolt in it for recovery attachment. I did this:


Cut loop of Kevlar to make recovery harness.
Epoxy into the inside of the 1in. small coupler, [that will be slid inside the fincan when finished]
I actually used a small slice of another coupler that fit inside this one to "sandwich" the Kevlar.[seen in upper left of photo, just sliced a bit out so I could compress it, to make it fit inside the coupler.] This is basically the same technique I used in the NC. No way the Kevlar can come off!

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Proper placement of recovery harness is just above the largest motor case you will fly/fit into the rocket.
Here you see the 6grain XL CTI and the AT 1380? [someone correct me if I did not remember] Lined up with rear of rocket to see how far north the coupler must go

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Close up reveals the magic number is [24in.] for the edge of coupler. I will use rivets to hold in the assembly, but not drilled through the coupler, too hard to locate them. Drilled above the coupler
I want the coupler removable to clean and also bang out motors [friction fitted] with a stick.
Insert the assembly & push past the rivet holes.
Insert rivets [2 opposite side from one another.... 180 degrees apart]
Pull assembly up tight to rivet so there is no slack.

Edit: since I built this 3 yrs ago, I have been using a more aero-dynamic approach. Instead of rivets which protrude into the airflow I would use #8 set screws, mounted flush with airframe, like method used in the SC 54 av-bay.

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Yeah the hole you see is a Snafu... I forgot about the Big AT case and began to drill holes for the CTI. Then had to move them. But hey....better me than you!

Now you have a nice clean recovery attachment point.
 
This is what it would look like in proper position internally, rivet in place. 2 rivets 180 degrees opposite on airframe.
NOTE: the rivets do NOT go through the coupler assembly, but are in there, so when the assembly is in place, it butts up to them. I just thought if I drilled into the coupler also, it would be miserable trying to align the holes for removal/replacement.

I'm sure the altitude junkies will use glue in technique, or flush mount screws of some type aero-dynamic trickery to squeeze out the last bit of performance.
I for one would like to see any tricks you use.
Edit: [of course now I use flush mounted set screws #8]

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There is a 1/8 pressure relief hole [for airframe to bleed off during ascent] drilled 1/2 between top of motor and bottom of av-bay [when installed in fincan]

I also put another smaller one down low[opposite side of airframe] for when I fly small motors to avert the possibility of the shock cord and nomex from blocking one of the holes.
 
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Thanks Jim for the info. I used a sim file from another build here on TRF,
but I adjusted all the weights and dimensions to my kit parts and mods.
I'll go back and start a new file and see if that makes a difference.

Darrel
 
Here's where all the fun begins, the av-bay:

For the Av-bay I used 6-32 threaded rod and eyebolts [welded shut]..... anything larger i would not have been able to fit my altimeter in. It IS that tight!

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After mounting all hardware, ground off excess to get more room. The sled fits on bottom rod. Had to tape battery in. Not enough room to get a wire tie around the battery in circumference or sled would not fit!

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Very simple sled,just bolt on altimeter [and a terminal block for Adept 22 to simply hook up, more on that later. One pic shows a PerfectFlite HiAlt 45, which is same size as Stratologger, other the Adept 22.

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But to utilize your space to the max, orient the sled NOT between the tie rods horizontally with a tube that fits over both, but rather vertically, so the tie rods fit above & below the sled. Sled is cut to fit below center line of av-bay, & snug enough that it can't move back & forth. Essentially "clamped"in place by the BP's on each end.
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Now there is plenty of room for electronics. Pic is another bay, but set up the same. Sled is used in both.
 
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Here are the Sim files for my rocket.

I don't draw all the parts, especially av-bay, BP's e-bolts, rods, etc. But I do weight the assembled bay with battery, sled, altimeter, rods etc. already installed for flight, Same for chute, nomex and shock cords, they just go in under chute weight. Even the fillets are in there. I weight the fincan before & after the fillets are done to get an exact weight.
So the total is correct and placed where it belongs.

The OR version has many flight sims in it, which compare very well with actual flights some are over, some under. That could be weather conditions ...temp, wind,location, etc.

The rocksim conversion from OR doesn't save the flights for some reason.

View attachment Blackhawk 38 mine (2).ork

View attachment Blackhawk 38 mine (2).ork.rkt
 
Jim,
What a wonderful thread. Great tips. I picked up one of these kits last year. I will review it carfully be for I start. SWEET!!! Tim Thomas L3
 
I BH 38 FINS.jpgBH38 LUG.jpg

I placed the front rail button just below the shock cord coupler mount to keep it from sliding down.
My fin fillets looked great like Crazy Jims' after pulling the Proline 4500 resin, but not perfect. After sanding them the
resin lost that sweet deep black color & were an ugly , sandy grey color, I carefully masked around the sanded
epoxy fillets & gave them a squirt of black paint before clear coating the bird.
The results speak for themselves.
Hats off to Wildman Tim for providing a great kit & an outstanding value.

Tim Stone, Northern Illinois
Going for L3 when my last kid is outta med school!
 
Sorry to dig this one up again, but it is a great thread. So, in Post#2, is this rocket flown off a rail or tower?
 
Thanks.

The reason I ask is that I have been simulating the BH38 in RasAero and get nowhere near 12k feet in your configuration. Only ~9000 ft with rail buttons. Take them off and the simulation says ~12000 ft. 3000' (33%) due to rail buttons? I don't think so.
 
This was an excellent read.

I got lucky picking up one of the $99 MC door busters this passed Friday.

Anything you'd change using current tech or materials Jim?
 
Not so much for the build, basically the same. Since the kit comes with NC bulkplate now, I would make a GPS/tracker bay in NC.

Since there are now 'fly-away' rail guides, wouldn't bother with rail buttons or guides.

If I were just sport flying, leave length alone. If going for altitude...would cut as much off airframes as possible, friction fit motor [which I do anyway, no internal retention, and use forward closure on motor to attach recovery gear.

Anyone else, what would you do different now?
 
Damn, I just finished mine. Can't wait to see how she compares. CJ, will you be talking about trackers? I sure hope so, I'm having a hard time figuring that out. I want to use a GPS tracker but don't think it's going to fit.

You can definitely incorporate GPS into 38mm PR FWFG VK NCs. You can fit a Telemetrum in there or a TeleGPS and Raven. I've done both in the two Blackhawk 38s I've owned and they fit fine. Plus you get the value add of converting it into a single break dual deploy vehicle.
 
Working from rear to front, push fin down into position.
Not to hard but firmly, you do not want to push out all the epoxy from under the fin.

Rotate guide and repeat for 2nd and 3rd fins.

Or just do one. Set aside to cure.


My guide held the fins a tad loosely so I improvised by using pencils to wedge them in place while curing so they could not move.

A little more tape to hold things proper, and all was in happy land for the night.

Also, wear gloves when mixing and using epoxy. Not trying to be a killjoy or anything. Not sensitizing yourself to epoxy means you get to build more rockets with it.
 
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