BlackHawk 29 Dual Deploy Build Thread

I wanted another MPR rocket that I can fly at my local field (G limited), but also take to the HPR field and get some altitude. I love the look of Wildman's BlackHawk 29 so the choice was easy.

I have never utilized electronic deploy / dual deploy so that will be the big learning exercise for this build for me. I have a suspicion I'll regret the tight confines of a 29mm AV bay as a first attempt,... but after this everything else will seem easier!

Additionally,... I'm more comfortable learning friction fit of motors with 29mm. Less mass if / when the motor ejects out the back!

My initial plan is to use engine deploy at apogee for a streamer,... with altimeter deployed main. On later flights I can switch to both events controlled by the altimeter.

I'm using this thread as a guide for the Av Bay...

https://www.rocketryforum.com/showthread.php?9689-29mm-Dual-Deployment

But any and all input in Av Bay construction will be appreciated!

Here are the bits...

(the long blue tube to the right is a 4' section of 29mm coupler not included with the kit, but planned to be used in Av Bay construction)

For the Altimeter I chose the Adept 22.

Does exactly what I need. Reliable. And the price is right!

Nice! You do nice work so I'll be interested to see what you come up with for the BH. I just completed a BH38 and it was a nice build.

I have to say that I am interested to see how you work the AV bay. I picked up a raven + 38mm ebay and that just presented a different set of challenges. I am not convinced that it is any easier but the magnetic arming IS pretty cool.

What is that part that looks like a thrust ring next to the nose cone? I picked up a partially built BH29 and I don't have that part....

mdoering said:

What is that part that looks like a thrust ring next to the nose cone? I picked up a partially built BH29 and I don't have that part....

Click to expand...

It's a short piece of coupler for attaching the shock cord to the fin can.

Have fun with this kit, it's both simple and difficult to build at the same time. Good luck with the av bay, I cheated and used a raven and featherweight 29mm av bay Have you considered tracking? I fly tracking in mine every flight over 2k feet, and have needed it every time. The small size plus speed and color make it disappear as soon as the motor burns out.

Agreed on tracking...the first "shake down" flight of my BH29 on a CTI F59 White Thunder was OUT OF SIGHT in a heartbeat. Made me reconsider (only for an instant...) beating an I243 White in it next spring at Kloudburst :grin:

Ah, thanks for that regarding the coupler... I have a long length I'll just trim a piece off of... What is that about 1"? I'm considering flying it single deploy first on something small like an AT F22 Black Jack so I get a nice dark stream of smoke to follow...

Yeah, it's about 1" long. Make sure you un-braid about 1/2 inch of the kevlar so you get a good solid bond to the coupler.

My first flight of my BH29 was on an I243 (go big or go home) to 10,500 ft at Mach 1.24. DD with the main at 1k feet, never saw it after burnout, but walked right to it with a tracker about 3000ft from the pad. Even then, without the chute, it would have been lost, as it landed in very tall grass.

weboide said:

Yeah, it's about 1" long. Make sure you un-braid about 1/2 inch of the kevlar so you get a good solid bond to the coupler.

My first flight of my BH29 was on an I243 (go big or go home) to 10,500 ft at Mach 1.24. DD with the main at 1k feet, never saw it after burnout, but walked right to it with a tracker about 3000ft from the pad. Even then, without the chute, it would have been lost, as it landed in very tall grass.

Click to expand...

Any structural mods for your flight? I swapped the conical NC for a Shockwave ogive model and added a conical closure to my 6XL case. Glad to hear you both beat mach AND the 10K barrier.

The only mod I did was to shorten it significantly. Everything else was stock and built as per the instructions. I got the whole bird down to 33".

weboide said:

The only mod I did was to shorten it significantly. Everything else was stock and built as per the instructions. I got the whole bird down to 33".

Click to expand...

Glad to hear you shortened yours. I was thinking of shortening as well. But not going that short. Hoping to trim about 6-8".

Quaranta said:

Glad to hear you shortened yours. I was thinking of shortening as well. But not going that short. Hoping to trim about 6-8".

Click to expand...

Mine's not DD...Crazy Jim said stuff a tiny 'chute in it and hit the button!
:grin:

jpummil said:

Mine's not DD...Crazy Jim said stuff a tiny 'chute in it and hit the button!
:grin:

Click to expand...

Shortening mine will be my final step prior to paint,... after fully rigged. Hopefully there will be some excess length that can be removed.

The biggest decision I need to make is what battery to power the altimeter.

A standard 9V doesn't fit in the coupler tube... but does fit in the 29mm tube. I could mount the batter in the PL section immediately forward of the AV Bay. Pro's of this are it is the recommended power source for the altimeter,... and easy use / sourcing of batteries. The cons are that the batter is external to the av bay. Maybe this is a bit complicated. Maybe not. Might make arming the av bay very easy...

An A23 12V doesn't provide enough amperage according to Adept...

Use an 11.1V Li-Po battery... and a trip to the hobby shop to find what fits...

Other batteries??

But I'm guessing someone here knows the answer. What is my best battery option? I'm leaning 9V...

Thoughts?

Quaranta said:

But I'm guessing someone here knows the answer. What is my best battery option? I'm leaning 9V...

Thoughts?

Click to expand...

Here is my answer: Blackhawk 29 dual deploy two-stage sustainer av-bay.

You might want to follow this thread and see what the outcome is. They are trying to figure out how to power an Adept with tiny battery.


https://www.rocketryforum.com/showthread.php?42747-Need-lipo-part-number

dixontj93060 said:

Here is my answer: Blackhawk 29 dual deploy two-stage sustainer av-bay.

Click to expand...

Very nice. I came across that while searching for 29mm av bays. Fortunately for you, the Raven has a capaciter allowing for smaller batteries. That was not enough of a reason for me to spend the extra $$$.

blackjack2564 said:

You might want to follow this thread and see what the outcome is. They are trying to figure out how to power an Adept with tiny battery.




https://www.rocketryforum.com/showthread.php?42747-Need-lipo-part-number

Click to expand...

Thanks. I'll be interested to see what Jon learns.

You can find very small (200maH IIRC) 7.4v LiPo batteries. I have a couple mounted on other av-sleds that use a Stratalogger. They are about 3/4rs the size of a 9v battery in all dimensions. Just don't know if they would work with the ADEPT22.

dixontj93060 said:

You can find very small (200maH IIRC) 7.4v LiPo batteries. I have a couple mounted on other av-sleds that use a Stratalogger. They are about 3/4rs the size of a 9v battery in all dimensions. Just don't know if they would work with the ADEPT22.

Click to expand...

Thanks. I have a several small Li-Po's for some Micro RC Heli's / planes.

I don't want to tread new ground in my first foray into DD, when I have a workable option (9V)... so if someone hasn't already flown the adept 22 with something else successfully,... I'm going to stick with 9V for reliability / safety.

That said,... I'd love to find a smaller battery that works. I'm just hoping someone else has done the hard work!

CF parts got the obligatory bath last night. The fin guides needed minor clean-up,... so that was done.

I'm going to use JB Weld to tack on the fins... one at a time. Due to the long set time,... this will be a 3 day proposition. Hopefully tonight I can get the leading edge of the fins bevelled,... bonding surfaces scuffed,... and the first fin applied.

Got the leading edges of the Fins beveled. Trailing edges and tip cord left square.

BT marked for fin placement.

Sanded boding surfaces of Fins and Body Tube with 40 grit.

I notched the fin guides with a rat-tail file to prevent inadvertent glueing of the fin guides to the fins / body tube.

Will get the first fin tacked on with JB weld tonight. I'm going to do them 1 at a time to avoid getting JB weld slop on the body tube.

Next AV bay question...

What is my best option for an arming switch? Magnetic? Screw driver operated through vent hole?

If the battery is external to the avbay... as it will be if I go with a 9V,... is it foolish just to arm / disarm via the battery terminal connection?

Thanks in advance?

I am a huge fan of the magnetic switches, especially for minimum diameter. However, if you don't like the idea of spending as much on a switch as you spent on your altimeter, a screw switch through a vent hole is a good option. The only problem I could see with that in a rocket this small is having to make the vent hole "really big" (relatively) in order to physically fit a screwdriver through. If you can get a switch with a nice small screw that you can operate with a jeweler's screwdriver, that would be optimal.

Also, for your 9v battery conundrum, I was thinking that perhaps extending the coupler and slotting it so that it fits around the 9v would work nicely to retain the battery, if you get what I'm trying to say. That would enable you to run one coupler, and if you were worried about ejection gas getting to your altimeter it wouldn't be too hard to make a middle bulkhead to go between the battery and altimeter sections of the coupler.

weboide said:

I am a huge fan of the magnetic switches, especially for minimum diameter. However, if you don't like the idea of spending as much on a switch as you spent on your altimeter, a screw switch through a vent hole is a good option. The only problem I could see with that in a rocket this small is having to make the vent hole "really big" (relatively) in order to physically fit a screwdriver through. If you can get a switch with a nice small screw that you can operate with a jeweler's screwdriver, that would be optimal.

Also, for your 9v battery conundrum, I was thinking that perhaps extending the coupler and slotting it so that it fits around the 9v would work nicely to retain the battery, if you get what I'm trying to say. That would enable you to run one coupler, and if you were worried about ejection gas getting to your altimeter it wouldn't be too hard to make a middle bulkhead to go between the battery and altimeter sections of the coupler.

Click to expand...

I'm actually thinking something similar for the battery. Glueing a section of slotted coupler tube in the payload section to secure the battery. Same concept,... but separate from the av bay. This will make sealing the av bay simpler.

RE switches... The most important criteria is safety. Simple reliable use is #2. Cost is a distant number 3...

Is no switch and just unplugging the battery a safe option since the battery is external?

The problem with plugging and unplugging the battery is you then have to disassemble your rocket most of the way to arm and disarm the electronics, and that creates a risk of accidental deployment due to the pressure changes it entails. You want to be able to arm and disarm your electronics from the outside, without taking anything apart. I'd say your best bet is the magnetic switch. They're simple, easy, cool (look, I arm my electronics by waving a magnet around!), and nice and small. Just make sure you have a way of knowing where the switch is after everything is together. It looks much less cool when you're slowly circling your rocket with the magnet waiting to hear your altimeter power up

weboide said:

The problem with plugging and unplugging the battery is you then have to disassemble your rocket most of the way to arm and disarm the electronics, and that creates a risk of accidental deployment due to the pressure changes it entails. You want to be able to arm and disarm your electronics from the outside, without taking anything apart. I'd say your best bet is the magnetic switch. They're simple, easy, cool (look, I arm my electronics by waving a magnet around!), and nice and small. Just make sure you have a way of knowing where the switch is after everything is together. It looks much less cool when you're slowly circling your rocket with the magnet waiting to hear your altimeter power up

Click to expand...

That's the advice I was looking for. It does sound like a magnetic switch may be my best option.

I am planning on using a switch ring on the av bay regardless of switch type. This will have the vent holes, and I can align the switch with a vent hole.

Good advice. Very helpful. Thanks.

Construction begins...

Ordered a magnetic switch from featherweight today.

https://shop.featherweightaltimeters.com/product.sc?productId=33&categoryId=2

Unless someone comes up with a certain battery solution,... I'm going with a std 9V for power.

Plan to start building the Av Bay tomorrow.

Fins 2 and 3 tacked on.

Fins tacked on and cured.

Tacking was done with a bead of slow curing JB Weld along the full length of the root edge.

Fillets will be done (soon) with the High Temp Epoxy provided with the kit.