My Rocketry Warehouse X-Celerator -- SKY BURNER

Thanks to Mark Hayes of Sticker Shock 23 for the awesome wrap. There is no paint on this rocket. Any flaws you see are because I don't know what I'm doing.

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WWooooooohooooooo,,,

On the money John............

February 22nd is the maiden right ???????????

What's the load it's goin up on ??????

Nice..........

Teddy

Nicely done!

You must have saved a ton of time not having to prime, paint and sand.

INCREDIBLE!
thanks for the compliments

the rocket looks GREAT! glad to help you out!

Fantastic!

Thanks, all.

Exactimator - I don't know. It was very meticulous to apply the wraps to the fins, and around the fins at the bottom. But, yeah, I think I probably saved some time. Considering it has been in the twenties and thirties around here, there is no way I could have painted if I wanted to. So considering I couldn't have painted until April, then yeah, I saved A LOT of time. :wink:

Ground testing this morning. Fingers crossed.

Ted - Actually, 2/21, next Saturday. I have a J380SS for first flight. Sims to 2871 ft. If all goes well, I have a K600W to try for 6300 ft. See you there ... :wink:

Mark - feel free to use any of those on your web site. Or if you want a different pose, lighting, whatever, let me know.

How did the ground testing go? I'm curious about how much BP you came up with.

How much does the rocket weigh loaded without the motor?

My ground testing experience was frustrating. I had a limited amount of time, and everything that could go wrong did. I won't go into details, but I ended up only taking one shot at each tube.

I tried 4g for the drogue. Maybe overkill, but I didn't get a good angle for the separation. It was so cold that my fingers were numb, and I was rushing. Info Central recommended 3.3 and four pins. I used two pins. Probably need to back down to 3g.

For the main, I used 2.5g, but got a really huge throw. Need to back that off to 2.2. Unfortunately, I think my Nomex pads were too small, and I scorched a hole in my chute.

Launch is Saturday, but now they are calling for snow and/or ice. If I don't make it Saturday, I will have to wait for the April launch. <sigh>

Why are you using pins for drogue event? Most 4" rockets I never use over 2.5 grams of BP in both sections.

For my 4" rockets, I use three 1/16" styrene rods for shear pins and 2 grams of FFFFG powder per charge. My bays are not overly huge, so the 2 grams is plenty for the volume.
I use pins in both ends, just because...

Adrian

Bat-mite said:

My ground testing experience was frustrating. I had a limited amount of time, and everything that could go wrong did. I won't go into details, but I ended up only taking one shot at each tube.

I tried 4g for the drogue. Maybe overkill, but I didn't get a good angle for the separation. It was so cold that my fingers were numb, and I was rushing. Info Central recommended 3.3 and four pins. I used two pins. Probably need to back down to 3g.

For the main, I used 2.5g, but got a really huge throw. Need to back that off to 2.2. Unfortunately, I think my Nomex pads were too small, and I scorched a hole in my chute.

Launch is Saturday, but now they are calling for snow and/or ice. If I don't make it Saturday, I will have to wait for the April launch. <sigh>

Click to expand...

Well, I'm glad it wasn't just me who got frustrated and scorched a hole in my chute.

On my X-Celerator I use 3 shear pins on payload and booster sections... and 2.5 grams each... 18"x18" Nomex.... 20 ft 3/8" kevlar shock cords both sections.

crossfire said:

Why are you using pins for drogue event? Most 4" rockets I never use over 2.5 grams of BP in both sections.

Click to expand...

The coupler is loose enough in there that I either need to use pins or tape wrap it. Rather use pins.

I came up with my charge amounts from Info Central, but I realize from ground testing that I overdid it a bit. I'll be backing off for launch.

Exactimator said:

Well, I'm glad it wasn't just me who got frustrated and scorched a hole in my chute.

Click to expand...

It's an awful feeling, isn't it? I just ordered three 12x12 Nomex cloths from Sirius Rocketry. Shipped already and should have them by Wednesday. Going to use two in the booster, one for E-charge and one for motor back-up. One in payload.

Bat-mite said:

It's an awful feeling, isn't it? I just ordered three 12x12 Nomex cloths from Sirius Rocketry. Shipped already and should have them by Wednesday. Going to use two in the booster, one for E-charge and one for motor back-up. One in payload.

Click to expand...

I tested the other direction – starting with smaller charges (based on what I use for my 4” Pike and working up). I keep going until I get a good energetic shot with a decent tug on the shock chord. Then I try the same amount to confirm.

I live in suburbia. My neighbors are pretty chill, but I don’t want to give anyone a reason to get nervous or call the police or fire. A pop here or there would be fine, but multiple ones over the course of a weekend afternoon and people might start getting concerned. Especially if they look in my direction and see a puff of smoke floating up and get a whiff of burned BP.

My solution is covering noise. I have a small generator that makes plenty of racket. If people hear a pop they’d probably think something was backfiring. I tape over all but one vent hole, assemble the rocket, and use a vacuum (more noise) on the av bay to simulate altitude. 90% of the time it works every time.

My test process is prep the charges, assemble the rocket, fire up the generator, turn on the vacuum, and BLAM! Then shut everything back down and inspect the results.

I got the drogue dialed-in relatively quickly because I only had to work up to 2 grams. The friggin’ main just wouldn’t work right. Rocketman sent a chute protector that was a 12” flat disk with the chute. I was folding the main, wrapping the protector disk around the bottom end that was up against the charge well, and packing it in snug. I was also topping off the charge well with dog barf for a little added protection.

The nose would pop off and the chute would come halfway out and stop. I got up to 2.5g and still had the same problem. Then I realized the charge was blowing around the protective disk and past the chute. I pulled the chute and found some singe marks and a hole about the size of the tip of my pinky. So I took everything in the garage and decided to try again when my frustration level was lower.

I ordered an 18x18” nomex protector from Madcow, which allowed me to make a nice burrito.
Then I filled in my pressure vent hole from halfway up the payload tube to just under the nosecone shoulder.
And I upped my charge to 3 grams.

It worked perfectly. Which is good, because much more of that BS and I would have thrown everything into the street and yelled “ROCKETRY IS CANCELLED!”

I think I will get to do some more testing. They are calling for ugly weather this weekend. One of our two vehicles is in the shop, and my kids have tickets to a show on Saturday. So I am going to miss this month's launch, and next month's, too, because I want to go to the annual Eagle Fest at the wildlife preserve.

So I hope to get some more tests in during March, maybe in better weather, and debut this bird at Red Glare in April.

I don't use the vacuum method. I unhook the leads from the altimeter and shove them through the switch hole. Then I use an Estes launch controller to fire the charges. The "continuity" test is enough to ignite the charge. (The Estes launchers have that "continuity" light bulb which takes a good bit of amperage to light. :wink: )

Funny about the main. I used 2.5 on mine, and it blew the NC so far out that I was afraid it was going to stress my harness. I thought I'd back off to 2.2.

Have you figured out where your CP is? I added a tailcone in Open Rocket and it moved the CP to 58.6 inches from the tip of the nose.

I don't trust my OR skills to accurately show the correct CG, so I always load the motor in the rocket and check real world. I'm still waiting on my AT L1000 from the BS sale, but I think I may have a stability margin issue.

Exactimator said:

Have you figured out where your CP is? I added a tailcone in Open Rocket and it moved the CP to 58.6 inches from the tip of the nose.

I don't trust my OR skills to accurately show the correct CG, so I always load the motor in the rocket and check real world. I'm still waiting on my AT L1000 from the BS sale, but I think I may have a stability margin issue.

Click to expand...

It should get more stable with the longer motor...but verification is verification.

Kenny

Gary T. puts the CP at 62" from the tip, which by my calculations is 20" from the bottom of the airframe. I still need to get about the business of finding the CG. I did my ground testes without a motor or AV sled.

I would think that adding a tailcone would move the CP aft, not forward. You're adding cross-sectional area to the rear of the rocket. Same idea as adding breadth to the fins. No?

Tail drag increases stability by bringing the CP aft. Tailcones actually move the CP forward because it reduces tail drag.

You remembered to plug your mmt tube during your ground tests, right? I forgot to do that during a round of tests on my Pike and was wondering why what should have been a sufficient charge was acting so weak.

Now that you mention it ....

I put a 5G casing in there, and meant to shove some Kevlar cloth inside, but forgot to. Woops. Well, more testing on the way.

John,
Yup she's lookin good man. Yeah I put the kits CP at 62" from the NC Tip, That's a ratio between RockSim and Barroman. If for instance you add a 2.5" tail cone to the kit that will put your CP at around 60" from the NC tip, again I'm using a ratio between RockSim and Barroman.

PS Here's a shameless plug for my Painkiller Micro as its on SALE! right now:

Thanks, Gary. I hope you'll be able to see her at Red Glare.

I am tempted by the PainKiller Micro, but I promised the wife only one rocket a year. :cry:

Have you launched yours yet?

Aarrgh. Was supposed to be today, but it friggin' snowed! Looking at Red Glade in two weeks.

Glad to know someone, somewhere is launching something. It has been a really rough last six months in MD. Rain, snow, wind, mud, or some combination of all of the above. :sad:

Had an excellent, very successful maiden flight today. 2328' on a J380SS. Perfect DD recovery. Woo hoo!

They fly nice, don't they?

Out of curiosity, what size BP charges did you end up with? Did you get a whistle as it went up?

Got any photos of the launch?

1. Yes!

2. I used 2.5 in the booster and 2.2 in the main. Don't think I got a whistle, but not sure.

3. There should be some soon on rocketrylive.com, and a video on MDRA's youtube channel, probably in a few weeks.