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littlemisterbig said:
Plus, i will be doing cable cutter deployment so i dont think it'll go off the field
Click to expand...


Do NOT underestimate the "drift" abilities of a lightweight rocket like a Blackhawk. Dual deploy or not, it can still drift away in a heartbeat (under drogue).
 
David...

What I would recommend. Get a streamer. No parachute.
Go drogueless from apogee until about 800 feet. At that altitude, deploy the biggest streamer you can possible shove in there. Like a 20 foot long nylon streamer. Go to a thrift store, get a thing of nylon cloth. Sew strips together, and attach some kevlar cord to the end in a loop. You now have a $5 streamer that you can see from a mile away. Also helps visibility on the ground. I'll send you some pics of mine.
 
blackbrandt said:
David...

What I would recommend. Get a streamer. No parachute.
Go drogueless from apogee until about 800 feet. At that altitude, deploy the biggest streamer you can possible shove in there. Like a 20 foot long nylon streamer. Go to a thrift store, get a thing of nylon cloth. Sew strips together, and attach some kevlar cord to the end in a loop. You now have a $5 streamer that you can see from a mile away. Also helps visibility on the ground. I'll send you some pics of mine.
Click to expand...

Yup, I want to see pictures also


Sent from my iPhone using Rocketry Forum
 
blackbrandt said:
David...

What I would recommend. Get a streamer. No parachute.
Go drogueless from apogee until about 800 feet. At that altitude, deploy the biggest streamer you can possible shove in there. Like a 20 foot long nylon streamer. Go to a thrift store, get a thing of nylon cloth. Sew strips together, and attach some kevlar cord to the end in a loop. You now have a $5 streamer that you can see from a mile away. Also helps visibility on the ground. I'll send you some pics of mine.
Click to expand...


for now on I'm dropping it with nothing. It is a strong rocket and it drifts too far with a parachute or streamer.
 
wfcook said:
Um...yes. OpenRocket calculates this. You can plot lateral position and even Latitude and Longitude if you want. You need to enter some basic parameters about the wind you expect during the flight in the 'Edit Simulation' dialog.
Click to expand...


Oh ok sorry. Ive never heard of this before!
 
This isnt a question for the black hawk, but are fillets really necessary on a rocket like the arcas?
 
In terms of drift, as long as you don't accidently pop a main at apogee, drogue-less it will drop like a rock - heres a GPS plot of my Blackhawk 38's flight to just under 5,000', you can see after apogee it fell straight down despite a 5-10 mph wind and landed about 100 yards from the pad. (the main parachute got tangled up so thats why there is no change in the drift @ 500')

I223.jpg

IMHO I would say how straight the rocket flies is more a determining factor for how far away it lands than drift
 
RocketHunter said:
In terms of drift, as long as you don't accidently pop a main at apogee, drogue-less it will drop like a rock - heres a GPS plot of my Blackhawk 38's flight to just under 5,000', you can see after apogee it fell straight down despite a 5-10 mph wind and landed about 100 yards from the pad. (the main parachute got tangled up so thats why there is no change in the drift @ 500')

View attachment 188826

IMHO I would say how straight the rocket flies is more a determining factor for how far away it lands than drift
Click to expand...

What was the descent rate when it was falling drogueless? And what motor was than on? What does your rocket weigh without motor?

Trying to do some calculations here and I'd sure like some real-world numbers so I can check in with reality.

Thanks.
 
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wfcook said:
What was the descent rate when it was falling drogueless? And what motor was than on? What does your rocket weigh without motor?

Trying to do some calculations here and I'd sure like some real-world numbers so I can check in with reality.

Thanks.
Click to expand...

From the kalman filtered velocity data, it looks to be about 80 ft/sec, with other flights closer to 70 ft/sec

I didn't have a super accurate scale but I think it was about ~2.3 lbs. Also mine was pretty draggy, with thicker fins because of the tip to tip, the slimline and large ACME rail guides. (With only a 5,000' waiver it was not designed for altitude!)

My Flights:
H100 Spitfire- 2,037'
H90 Loki red- 2,451'
I140 White Lightning- 4,462'
H170 Metalstorm- 4,288'
 
RocketHunter said:
From the kalman filtered velocity data, it looks to be about 80 ft/sec, with other flights closer to 70 ft/sec

I didn't have a super accurate scale but I think it was about ~2.3 lbs. Also mine was pretty draggy, with thicker fins because of the tip to tip, the slimline and large ACME rail guides. (With only a 5,000' waiver it was not designed for altitude!)

My Flights:
H100 Spitfire- 2,037'
H90 Loki red- 2,451'
I140 White Lightning- 4,462'
H170 Metalstorm- 4,288'
Click to expand...

Thank you, that is really, really helpful!. Interestingly, the flights with the smaller motors are very close to OpenRocket predictions, while the faster, higher flights are underestimated by OR. With a couple of rail buttons on there, RASAero overpredicts the slower flights and pretty much nails it on the faster ones. What kind of rail guide are you using for this bird?

Out of curiosity, and at the risk of hijacking the thread, do you happen to have similar data for your flying case rocket? That thread of yours has been inspiring. Thanks either way...
 
About friction fit: There is an easy way to make sure "snug" is snug enough. I have used this in my rear eject model to ensure the rear plug stays in place, and ensure the friction fit motors stay in place. https://www.rocketryforum.com/showthread.php?67272-Estes-V2-Steam-Punk-Forward-Mounted-Canted-Cluster-build-thread

Step 1: Measure how much force it takes for the NC to come out. Tie or clamp a hook onto the NC so it is linear with it. Then attach a spring scale or start adding weight till the NC comes out.

Step 2: Then do the same for the motor. For the motor resistance, I would feel comfortable with 2X - 3X the NC resistance.

Now you have quantifiable data that your motor is "snug enough". This should help alleviate concerns your RSO may have. Of course, if your club has a rule, nothing you do will change that.
 
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littlemisterbig said:
For motor retention, I was thinking of using one of the aeropack minimum diameter retainers and killing two birds with one stone, i would have motor retention and shock cord anchor point. Has anyone here used them? Would you recommend them?

Heres the link https://www.apogeerockets.com/Build...eter_Retainers/38mm_Minimum_Diameter_Retainer
Click to expand...

I feel so ignored lol. I mentioned these not too long ago and I did say I would recommend them over outer retainers to get more speed and altitude. I have yet to use them, but I would use them when it comes to minimum diameter rockets.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
I have a set of those and plan on using them in a min diam project. They are a bit heavier than necessary IMO. The retaining bolt is 5/16" which seems like overkill to me. And the actual retainer unit has a VERY large gluing area and takes up a bit more length in the body tube than I think is necessary.

I can imagine a slicker system, but I cannot purchase one ready made and I don't have access to all the machining tools required to make it myself. A few back-of-the-envelope estimates leads me to believe that the weight of the Aeropack retainer is more than offset by the reduced drag relative to anything other than friction fit. So the Aeropack min diam retainer is probably the best commercial-off-the-shelf solution for maximum performance if you don't want to go with a friction fit.


Sent from my iPhone using Rocketry Forum
 
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littlemisterbig said:
For motor retention, I was thinking of using one of the aeropack minimum diameter retainers and killing two birds with one stone, i would have motor retention and shock cord anchor point. Has anyone here used them? Would you recommend them?

Heres the link https://www.apogeerockets.com/Build...eter_Retainers/38mm_Minimum_Diameter_Retainer
Click to expand...

Go for it. I have bought four of them and used only one in a 54mm bird; reason being I ended up not wanting to use them. Some will complain about installing them but it is a simple task, my complaint only comes from the added length (38mm-54mm size). I ended up building my own retainers that take up essentially no extra space and was happy. Bottom line out of all the commercially available retainers I would go for the Aeropack minimum diameter retainer hands down… over the slimline also, just makes the most sense when flying MD.
 
littlemisterbig said:
Ok, thanks but how am i supposed to epoxy it
Click to expand...

Your going to need a long stick that is for sure. Put epoxy with the stick in the area to be bonded and then shove the retainer in there with the stick. The stick can also help in measuring how far you need it to go into the tube.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
littlemisterbig said:
Ok, thanks but how am i supposed to epoxy it
Click to expand...

What I do is first use the motor with the MD retainer attached on top, to measure/mark where it will go. Then I take a flap wheel (extended) to abrade the inside of where it is to be epoxied or you can also secure sand paper to a dowel as a cheaper method. Next I take a dowel to apply the epoxy to the given area, you can also secure a foam brush to the dowel to apply the epoxy to the said area. Finally I slide the MD retainer up the airframe (move it around once it comes into contact with the epoxy, this will spread the epoxy) and in place, then let cure. I do this with the retainer on top of the adapter and secured to motor, this guarantees it to be placed to the desired position. There are other methods of installation but I prefer this way, just use common sense. Hope that helps.
 
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littlemisterbig said:
Ok, thanks but how am i supposed to epoxy it
Click to expand...

First attach the retainer to the longest motor that you will use. Best to use a motor liner without the grains of fuel. Measure the length of the retainer. You can hold the motor case and retainer up to the outside of body tube to approximate where the retainer will go. Sand the inside of the tube out well with 80 grit where the retainer will be epoxied. Before any epoxy, make sure that you can slide the motor and retainer up to its correct position and back out. I had to sand down my retainer pretty well to get this to work. Once you are happy with in and out, slide up to final position. Mark inside of tube from the top, where the retainer will reside. Then back the assembly off the length of the retainer that you measured. Add epoxy with a stick from the top. This way, no epoxy can get below your retainer and into the tube where your motor goes. Push assembly up into final position and rotate clockwise to help spread epoxy around retainer. Rotating counter clockwise will probably loosen motor from retainer. There you go. There are other ways, but make sure that you don't get epoxy into motor area. AeroPack suggests using JB Weld / acetone (like 2 / 1 or something). Follow AeroPack retainer instructions. Enjoy.
 
conman13 said:
I do it all the time with the supervision of a certified adult member.
Click to expand...

as bob linked -

Level 1 Junior High Power Participation
(160.01 to 640.00 Newton-seconds impulse)

Qualifying junior members at this level permits them to fly single or multiple motor rocket flights with motors having a maximum total impulse of 640.00 Newton seconds.
The qualification flight and all future flights must be single deployment only. This is due to regulatory requirements of ejection charges used in dual deployment systems. On board electronic devices are permitted as long as they are not used for deployment.


-------

Pretty clear there.
 
DizWolf said:
as bob linked -

Level 1 Junior High Power Participation
(160.01 to 640.00 Newton-seconds impulse)

Qualifying junior members at this level permits them to fly single or multiple motor rocket flights with motors having a maximum total impulse of 640.00 Newton seconds.
The qualification flight and all future flights must be single deployment only. This is due to regulatory requirements of ejection charges used in dual deployment systems. On board electronic devices are permitted as long as they are not used for deployment.


-------

Pretty clear there.
Click to expand...
Now,this is going to sound worse than I want it to but, who really cares? I have never heard or anyone actually enforcing that rule. At my club, minors fly with electronics all the time. I plan to start soon as well. "due to the regulatory requirements of ejection charges" , So what? I get someone else at my club to store my black powder. Go for it David, if you want to build a DD rocket, nobody is gonna stop you from flying it. Honestly, most of the rules are stupid and aren't enforced. I don't even see why there has to be an age limit on most things. We have to have an adult sponsor anyways that puts their name on the flight card, they are over 18 and they can use DD whenever they want.
 
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