Wildman Blackhawk 38mm Build thread

[DM1975]

Looking good! It makes me want to build another one. I got one of the first batches of 24's with the CTI casing deal a couple years ago. First flight I put it up on an AT RMS F39 T and never seen it again. Thank goodness my CTI case came in late so I didn't lose it too.

 

[Quaranta]

Can someone tell me what the BH-38 weighs?

I like to have a project in the wings,... My next order from Tim, considering ordering the BH-29 vs 38. Thx.

 

[BLKKROW]

Can someone tell me what the BH-38 weighs?

I like to have a project in the wings,... My next order from Tim, considering ordering the BH-29 vs 38. Thx.

Mine will be a little on the heavy side, but I can throw it on my scale today and get a weight without recovery gear.

Looking good! It makes me want to build another one. I got one of the first batches of 24's with the CTI casing deal a couple years ago. First flight I put it up on an AT RMS F39 T and never seen it again. Thank goodness my CTI case came in late so I didn't lose it too.

Now your making me even more worried about loosing mine :y:

I do not know if I will be working on it today, today is my first time working a Sunday in years. So I may or may not have time to get something done, I might use my new table saw to cut out a new Sled for my Av-bay. Or I might start to sand the fillets, so hopefully look for updates soon, if not there will be some on Thur/Fri.

 

[RktSledhead]

Can someone tell me what the BH-38 weighs?

I put my 38 on the scale just to get an idea on weight. It is just slightly under 2 pounds with the av bay/tracker and recovery gear (no motor hardware) I still have a couple additions but I'm hoping to keep it right at 2 lbs. maybe ever so slightly over.

 

[Quaranta]

I put my 38 on the scale just to get an idea on weight. It is just slightly under 2 pounds with the av bay/tracker and recovery gear (no motor hardware) I still have a couple additions but I'm hoping to keep it right at 2 lbs. maybe ever so slightly over.

Thanks. That'll be a screamer.

 

[BLKKROW]

Thanks. That'll be a screamer.

Sorry I did not reply yesterday I forgot to bring my scale to my parents house where I work on my rockets.

 

[blackjack2564]

My fincan was in a field over winter & got hit in spring when farmer was disc-ing the field for planting. Amazingly I got it back with just 1 fin missing and a gouge on the tube.

Sunday was first flight since repairs were made so I took it easy. Just a 2-grain blue thunder. H-242-t.

Went 2497ft. Nice flight and short recovery walk. On smaller motors I put the tracker on the shock-cord in fincan. Extreme flights [it has flown to 12,000] I put it the the NC.

1 & 2 grain 38 motors are perfect for shakedown flights. Ya can see if all the gear performs as planned, and make adjustments if not. Then stick a big one in there and blow the cob-webs out.


I still cannot believe it got run over by the disc and survived with so little damage..oint:

This rocket goes to every launch with me. Easy to prep & fly, great altitude on small motors.

 

[BLKKROW]

My fincan was in a field over winter & got hit in spring when farmer was disc-ing the field for planting. Amazingly I got it back with just 1 fin missing and a gouge on the tube.

Sunday was first flight since repairs were made so I took it easy. Just a 2-grain blue thunder. H-242-t.

Went 2497ft. Nice flight and short recovery walk. On smaller motors I put the tracker on the shock-cord in fincan. Extreme flights [it has flown to 12,000] I put it the the NC.

1 & 2 grain 38 motors are perfect for shakedown flights. Ya can see if all the gear performs as planned, and make adjustments if not. Then stick a big one in there and blow the cob-webs out.


I still cannot believe it got run over by the disc and survived with so little damage..oint:

This rocket goes to every launch with me. Easy to prep & fly, great altitude on small motors.

So question, as you can see with my coupler design it pretty much is like a cork in the main body tube. I was thinking, I should probably drill some holes in the washer to allow for the ejection charge to pass through. What do you think?

Just for kicks and giggles.

 

[cwbullet]

As long as the hot gasses are not going to hit an altimeter. This is ok.

 

[Quaranta]

Sorry I did not reply yesterday I forgot to bring my scale to my parents house where I work on my rockets.

No apology necessary! Thanks again.

 

[blackjack2564]

So question, as you can see with my coupler design it pretty much is like a cork in the main body tube. I was thinking, I should probably drill some holes in the washer to allow for the ejection charge to pass through. What do you think?

If I read you correctly, you're talking about the recovery attachment coupler & washers?
If so... no holes are needed.... keep the airframe sealed. Less charge needed at apogee, and less chance of blowing the motor out the rear from gases going through the washers and impacting the motor itself.

If I'm reading wrong, please clarify your above statement.

 

[blackjack2564]

I put my 38 on the scale just to get an idea on weight. It is just slightly under 2 pounds with the av bay/tracker and recovery gear (no motor hardware).

Mine weighs 2.85 lbs ready to fly sans motor.

 

[BLKKROW]

If I read you correctly, you're talking about the recovery attachment coupler & washers?
If so... no holes are needed.... keep the airframe sealed. Less charge needed at apogee, and less chance of blowing the motor out the rear from gases going through the washers and impacting the motor itself.

If I'm reading wrong, please clarify your above statement.

No you understand correctly, the only thing im worried about is the motor I want to use has motor ejection. I will be taking out the black poweder but I am still worried about it destroying the fincan.

 

[blackjack2564]

No you understand correctly, the only thing im worried about is the motor I want to use has motor ejection. I will be taking out the black poweder but I am still worried about it destroying the fincan.

No worries mate! After removing the BP, just mix some 5-10 minute [or whatever you have] and fill the well. Problem solved, no burn thru can happen with a plugged well.
I now screw 3/16 eyebolts into the touch hole and fill well with epoxy on my minimum 38's for recovery attachment. On 54's I do the same with 1/4in eyebolts.
If it's not a minimum rocket and I remove the BP on 54 motor [I am assuming we are talking CTI's on all these] a penny will fit perfectly when wedged in!

 

[BLKKROW]

No worries mate! After removing the BP, just mix some 5-10 minute [or whatever you have] and fill the well. Problem solved, no burn thru can happen with a plugged well.
I now screw 3/16 eyebolts into the touch hole and fill well with epoxy on my minimum 38's for recovery attachment. On 54's I do the same with 1/4in eyebolts.
If it's not a minimum rocket and I remove the BP on 54 motor [I am assuming we are talking CTI's on all these] a penny will fit perfectly when wedged in!

Yes I am speaking of the CTI reloads, I did not think of the epoxy method. That makes perfect sense, thanks for the input, hopefully I am not ruining your beatiful kit too much.

 

[blackjack2564]

Nah man.... it ain't about how it looks, as much as it is about how it flies! So just get it built & go fly the ---- out of it.

Just make sure it's all about having fun.

 

[BLKKROW]

Nah man.... it ain't about how it looks, as much as it is about how it flies! So just get it built & go fly the ---- out of it.

Just make sure it's all about having fun.

Another question, how do you finish your Blackhawk(s). I really would like to have a nice finish on mine.

 

[blackjack2564]

Lots & lots of elbow grease.....

several light coats of DupliColor clear, then buff with ScotchBrite pad [green ones like ya do dishes with] till the shine is gone on everything with out cutting back to the raw tube. Then do it again...then do it again... then finish with a nice even semi-heavy coat. takes lots of practice to get it right.

 

[Quaranta]

Lots & lots of elbow grease.....

several light coats of DupliColor clear, then buff with ScotchBrite pad [green ones like ya do dishes with] till the shine is gone on everything with out cutting back to the raw tube. Then do it again...then do it again... then finish with a nice even semi-heavy coat. takes lots of practice to get it right.

Either thats a 24mm in the pic or you have some GIANT hands!!

What color orange/tangerine is that? Paint or decal? It looks fantastic.

 

[blackjack2564]

Rustoleum orange/red florescent, must be done over white primer.

Many times all that is seen from a great distance is the orange/red tips of fin, makes finding a black rocket in dirt fields or grass a whole hole lot easier. I always go with bright florescent chute too.


PS the final coats are shot over the decals to give them depth.

 

[Quaranta]

Wow that looks great. Thanks for giving your finishing secrets. I ordered a BH 29 from Tim this week... You give me something to aim for.

 

[dixontj93060]

Rustoleum orange/red florescent, must be done over white primer.

Yep, here is a BH29 utilizing said Rustoleum Red-Orange Florescent (w/white base coat) in a dual deploy, two-stage configuration.

 

[Windeavor]

Cool bird!!! If using rail buttons on a minimum diameter Black Hawk what is the best way to attach them to the aft part of the BT?

 

[BLKKROW]

Cool bird!!! If using rail buttons on a minimum diameter Black Hawk what is the best way to attach them to the aft part of the BT?

I was planning on using rail buttons, all I was going to do is drill the hole in the body. Then take the the rail button's screw and trim it down to size so it only has room for the button and a little more for the thickness of the body of the rocket.

I got some more work done, I cut a new Av Sled with my table saw so much better then the first attempt with my dremel. I also started to finish my fillets, I filled in the one that was missing. I just have to sand one set of fillets and redo them, as they have some major defects.

After the fillets, the only thing left to do on the body is the vent holes, and shear pins holes.

Now two questions on those subjects, the vent holes for the altimeter should be as close as possible to the barometer? Also with the shear pins should I thread the hole it self? Or just use some muscle to get them into the hole?

 

[jsargevt]

Now two questions on those subjects, the vent holes for the altimeter should be as close as possible to the barometer? Also with the shear pins should I thread the hole it self? Or just use some muscle to get them into the hole?

For the vent holes I think that you just want them to be equally spaced on or near the center of the AV bay. For the shear pins - if you can thread the hole that might make install a little easier but i have just pushed them in with a little force and it works fine.

 

[BLKKROW]

For the vent holes I think that you just want them to be equally spaced on or near the center of the AV bay. For the shear pins - if you can thread the hole that might make install a little easier but i have just pushed them in with a little force and it works fine.

The middle of my AV-Bay is where the fincan meets the upper body. Would I just drill them on that crease?

 

[jsargevt]

The middle of my AV-Bay is where the fincan meets the upper body. Would I just drill them on that crease?

That is a good question....I have drilled on the seam and it works. Some people might like to do one on the seam and the other 2 1/2" up or down so there is no question of alignment.

Curious to know what others have done as well.

 

[BLKKROW]

That is a good question....I have drilled on the seam and it works. Some people might like to do one on the seam and the other 2 1/2" up or down so there is no question of alignment.

Curious to know what others have done as well.

I figure if you drill the holes on the seam it can increase the chance of premature deployment. But I will be using shear pins, so I think either way should work.

Also should I add some holes to prevent high pressure inside the body since it will be reaching altitudes of 4000+Feet, or will the shear pins prevent that?

 

[jsargevt]

I figure if you drill the holes on the seam it can increase the chance of premature deployment. But I will be using shear pins, so I think either way should work.

Also should I add some holes to prevent high pressure inside the body since it will be reaching altitudes of 4000+Feet, or will the shear pins prevent that?

I checked the PDF on the wildman site for the BH38 build and here is what CJ does:

Av-bay held in by 2 rivets opposite on another. 2 tiny vents between
them. Positioned 1 1⁄2 from edge of airframe. 5/32 bit used for drilling rivet holes.
Assemble, push the 2 airframe sections together and drill hole [5/32] centered on joint.

So the vent holes / static pressure ports are between the rivet holes with a half-hole for the wire. I think that a pair of 3/32 holes would be more than enough for that AVbay. You could probably get by with a pair of 1/16 since you will have the half-hole for the power wire and you will have that bit in the drill for the airframe holes as noted in the instructions:

Drill small [1/16] vent hole in the middle of both airframe sections to bleed off internal pressure during flight.

I am no expert on static pressure port sizing, just taking a whack at it based on the page here: https://www.vernk.com/AltimeterPortSizing.htm If anyone wants to do the math feel free to correct me.

Hope this helps!

 

[Neuport]

Also should I add some holes to prevent high pressure inside the body since it will be reaching altitudes of 4000+Feet, or will the shear pins prevent that?

The instruction manual suggests a 1/16" vent hole in the middle of each tube and a shear pin to hold on the NC. Mine is set up exactly that way. You may eventually launch it to 3x that height so why not included the vents; its a couple of simple 1/16" holes that will take less than a minute to drill.