Torn Between Scylla and Charybdis

Well, I was able to get all four fins attached today.



Hopefully tomorrow I can start on the fillets.

mannyskid said:

Well, I was able to get all four fins attached today.

View attachment 159614

Hopefully tomorrow I can start on the fillets.

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I like 4-fin rockets. They just look cooler.

CarVac said:

Not to take any unnecessary digs at your record or anything, but isn't that the photo you take after the rocket shreds?

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Cold, man, ice cold. Keep it up and I'll have to dig out pictures of your G handicapped record attempt and show them to Manny, just to make sure he doesn't take you too seriously. =)

So yesterday, on my way home for spring break, I decided to stop by Princeton for the QCRS March launch to fly Charybdis. I did all of the fillets and altimeter bay work in the past few days, so this is a very last second rocket. I wanted to fly it to a low altitude on a K630, but after realizing that the coupler for my adapter was much too tight and would require much sanding and more work than could be done the night before the launch, I called up Jason to arrange a 75mm motor to fly. He reluctantly gave up a 75mm 3 grain albino assault motor, about an 3500 Ns L900 (in exchange for another motor) to fly in this rocket.

After a couple hours of drilling holes and mucking around with it on the field, I was ready to fly.
Here is a picture of me with it before flight:


And slow-mo video by Jason Griffin:
[YOUTUBE]ELSuhjqUmjY&list=UUViOUGWubr9d7u2BpvyCN1g[/YOUTUBE]

100% successful flight with good recovery about 1.5 miles away. I haven't downloaded the RRC3 data, but from what I remember on the field I think it was somewhere around 14,000' which was pretty close to the RasAero simulation.


Before I take it apart and clean it, I wanted to take some pictures to describe the recovery system.





These two pictures show the recovery sprawled out. It's a pretty simple set up, parachute in the nose cone using the shoulder as an altimeter bay. For charge holders, I was testing out the high altitude charges, they're held in 3/4" brass tube with epoxy caps at both ends and 3 gams black powder.



Now it's time to do some carbon lay-ups in preparation for a little bit faster flight with a CTI M2250 that hopefully should fly in April in Argonia. I'm thinking 2 layers, vacuum bagged with aeropoxy.

Manny

Manny....That was a really fine flight and a good looking rocket. Hope all is well. Greg Olson

Manny, I have the recovery set up that exact same way on my most recent 98mm min dia iteration, except with the main in the bottom part and a drogue in the nosecone (weight differential between the two parts is significant enough that I felt a drogue was necessary).

Good call on skipping the layups! Tell Ejim and Niang to take it easy on us second round in San Antonio. I'll be at the game!

S

Sweet!

prophecy said:

Manny, I have the recovery set up that exact same way on my most recent 98mm min dia iteration, except with the main in the bottom part and a drogue in the nosecone (weight differential between the two parts is significant enough that I felt a drogue was necessary).

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I didn't feel like I needed a drogue on this one, since it was so light. Are you going to be flying that 98mm at Argonia in July? If so I may be there to see it.

prophecy said:

Good call on skipping the layups! Tell Ejim and Niang to take it easy on us second round in San Antonio. I'll be at the game!

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I'm considering not doing lay-ups for the next flight but I'm not sure, that M2250 is a nasty beast!

From what I've seen of them, they won't.....

Hey Manny
I just checked the Kloudbusters website and the July launch this year is going to be a one day launch.
July Fun Fly Sat. July 12.

lmt56 said:

Hey Manny
I just checked the Kloudbusters website and the July launch this year is going to be a one day launch.
July Fun Fly Sat. July 12.

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Yep, the July launch to go to is LDRS33 .

dixontj93060 said:

Yep, the July launch to go to is LDRS33 .

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Yeah, but LDRS is only 20 minutes down the road from me, I have to drive SOME appreciable distance to a launch for July...

Manny what's the deal? Are you not a basketball fan? How 'bout them Cyclones?

mannyskid said:

I didn't feel like I needed a drogue on this one, since it was so light. Are you going to be flying that 98mm at Argonia in July? If so I may be there to see it.



I'm considering not doing lay-ups for the next flight but I'm not sure, that M2250 is a nasty beast!

From what I've seen of them, they won't.....

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M2250 is pretty tame, I did my L3 on it It's an awesome motor.

Be aware The motor needs to be assembled the night before, the grains require bonding to the liner. You'll need gorilla glue and something to ram the gains down the liner with. We had two of us sitting on a plank of wood trying to get the thing together at one point (I forget at which point we got stuck)... ~200kg of weight on the motor. I know you can usually get away without grease, but you *need* it for this motor. Lots of it. High temp bearing grease... everywhere. I had mine fairly well slathered in grease and still took about an hour to get the spent liner out.

Manny,

Great looking build; congrats on the successful flight!!! Looks like a solid design and build plenty capable of M motors. Looking forward to seeing this one fly in the future; I won't even hide under a vehicle!:wink:

Still planning a Black Rock trip in '14?

-Eric-

dixontj93060 said:

Manny what's the deal? Are you not a basketball fan? How 'bout them Cyclones?

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I'm pleased with how we're doing this year, I think we have a good chance of winning the tournament. :wink:

Issus said:

M2250 is pretty tame, I did my L3 on it It's an awesome motor.

Be aware The motor needs to be assembled the night before, the grains require bonding to the liner.

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Oh yeah, no stranger to grain bonding here, biggest one I've done was a 98-6gXL which was actually not very difficult. I've flown the M2250 before but haven't had any issue with the liner. The last one I flew I didn't grease the liner and it slid out pretty easy, even after sitting in the case for over a year! I never grease my liners, just because I find that greasing liners, especially phenolic ones, leads to them sticking after the grease gets hot.

ECayemberg said:

Manny,

Great looking build; congrats on the successful flight!!! Looks like a solid design and build plenty capable of M motors. Looking forward to seeing this one fly in the future; I won't even hide under a vehicle!:wink:

Still planning a Black Rock trip in '14?

-Eric-

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Thanks Eric!

I am still planning on going to Black Rock for Aeronaut in August, and I did want to talk more about it with you in regards to details. I'll shoot you a PM and we can talk more about it.

If you go, you will get to see a version of this rocket fly, possibly past 50K!

Manny

dixontj93060 said:

Manny what's the deal? Are you not a basketball fan? How 'bout them Cyclones?

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Kane traveled. An eye for an eye in that we were both missing our second best player and so post-travel, the shot was hit over a walk-on.

I've got some good friends on that team and that was the second year in a row it's ended like that, on my birthday.

I flew the rocket again yesterday in Argonia at Kloudburst with some interesting results.

The motor of choice for this flight was the CTI M2250 C-Star. Attached you will find the data from the Raven. The rocket broke mach in less than a second and below 300' with my new personal (shredless) speed record of 2,012 miles per hour, or ~M2.7. Taking an average between the Missile Works and the Raven, the max altitude was ~24,000 feet. My friend/roommate/rocket teammate Joel had designed a payload for the other rocket we flew this weekend. The payload was a thermocouple glued into the nose cone and hooked up to an Arduino measuring stagnation point temperature (which actually turned out to be measuring nose tip temperature). We flew it on our school rocket that went on an L730, when we got the board back, we found that the power from the board had been disconnected during flight, so we spent the night resoldering and fitting the payload into my rocket. The max temperature experienced during the flight was 269 degrees Celsius ( 516 Fahrenheit!).

I did experience a bit of a failure during the flight, however. In the mad rush to get this thing on the pad to beat the incoming weather, I seemed to have broken the leads to the main charges, so there was no parachute, so it broke two fins when it hit the ground. No worries though, it's an easy fix and I know now not to rush like that again. It seems like the fillets broke in a pretty jagged fashion which leads me to believe that I did a decent job gluing them on. All in all, I'm pretty satisfied with how the flight went. I should be getting the really awesome pad videos in the next couple days and will be sure to post them then.

Manny











View attachment Scylla and Charybdis 2.FIPa

Manny, is that RocketPoxy on the fillets? /Tim

Good eye Tim. Rocketpoxy was used head to toe on this rocket. It's good stuff and can withstand the brutality of high speed flight. I'll be using it again to re-attach the fins.


Sent from my iPhone using Rocketry Forum

Whoops, forgot this picture, this is how I found the fins in the dirt.

hmmmm 269c, very interesting, I wonder what the temp would be on say a .9 mach flight. Great info, sorry to hear about your chute prob, but also glad to hear it's repairable.

Can't wait to see the video....Squirt! Hey, you've got a good attitude about the whole deal and, your able to rebuild!

Maybe see the results at Airfest? You KNOW i'll be there!

mannyskid said:

After a couple hours of drilling holes and mucking around with it on the field, I was ready to fly.
Here is a picture of me with it before flight:
View attachment 165940Manny

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View attachment 169098

I'm STILL seeing a slight resemblance here between the two species...College sure has *cleaned* you up my young friend!

mannyskid said:

Oh yeah, no stranger to grain bonding here, biggest one I've done was a 98-6gXL which was actually not very difficult. I've flown the M2250 before but haven't had any issue with the liner. The last one I flew I didn't grease the liner and it slid out pretty easy, even after sitting in the case for over a year! I never grease my liners, just because I find that greasing liners, especially phenolic ones, leads to them sticking after the grease gets hot.

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The liner came out of mine no problem, I wouldn't use grease normally either however there was no way we were getting this thing in without it. That motor was a huge pain to get together, way worse than you'd usually expect for one. We've only launched 2 or 3 in the state I live, and none of the others were this bad.

I received a pleasant email today during this terrible week known as dead week filled with wonderful pad video of the rocket I flew a few weeks ago. So, without much ado, here is the pad video taken by Brendan Cunningham:

[YOUTUBE]V-Mtdxw6v1E&list=UUwi4ptaPn3aUH3_2PheECfQ[/YOUTUBE]

Brendan also set his iPhone beside the pad facing up. There were only a couple good frames, but here's a decent one:



Enjoy,

Manny

I realized that I forgot to post this:

When I got back from school in early May, I decided I wanted to do another test flight of this airframe at the QCRS may launch. I quickly sanded the old glue off, mangled my fin guides and glued on the fins the night before the launch. I had called up Jason Griffin a week before the launch to get a motor made for the launch. This time, it was a 3 grain 75mm motor of the Albino Assault flavor; the same as what I flew in it at the QCRS may launch, but this time he left out the Oxamide. The motor in march was about an L700, this time it was about an L1300. The rocket got up and left in a hurry!



Flight pictures by David Reese.





The .FIPa file is attached. Over 15,000 feet and Mach 1.8! This third flight with good data gives me a pretty good idea of what it's going to do with the M2245. For this flight, I'm predicting an apogee of ~50,000' and a max velocity of M3.6. This flight is going to take some serious construction, and with the launch only one month away, I'd better get to work on it.

Manny

I received the first thing that I need to begin construction on Scylla, the fin stock. I spent some time trying to figure out what material I wanted to use for my fins. I settled on 1/8" unidirectional carbon from Dragon Plate. I was really torn between getting either 1/8" or 3/16" carbon. Once I ordered it, I had some regret of not getting the 3/16" because my failure from last year is still firmly implanted in the back of my mind. I got the plate today, and I am very pleased. The plate is EXTREMELY stiff.



I won't be able to start construction for a couple weeks, I'll be in New York this weekend and in Argonia the next, so I'll start when I get back. I have to stop over at Wildman's to pick up the tube, the new av-bay coupler and the nose cone.

To bond the fins and setting the fillets, I'm going to use proline 4500. The overlays are going to have 1 layer on the fins only and 4 layers tip-to-tip. The overlays are going to be done entirely with Cotronics 4461 high temperature epoxy and vacuum bagged. I've seen this epoxy work very well on other high velocity flights, but I don't plan on having any ablative or other protection on the lay-ups, so we'll see how they handle past M3.5.

Manny

I realized that I have been falling behind in this thread. I have been diligently working on this rocket in preparation for Aeronaut next weekend.

Last weekend, I took the carbon fiber plate over to Wildman's, and we cut them on his CNC machine and we beveled them. We decided not to bevel the trailing edge for fear of having them get sucked into the saw blade. 5 fins were cut, and one of them did suffer this fate.



I used the same fin guides as for Charybdis (practice rocket), on this one as they both used 1/8" thick fin stock. Fins and tube were sanded with 150 grit sandpaper and cleaned thoroughly with isopropyl alcohol. They were glued on with proline 4500. The fillets were also done with proline 4500. I wanted to make the fillets on this fairly large as to increase the bonding area of the fins and also to allow the carbon tip-to-tip to contour better. My definition of large fillets for this are that they are the same size at the fillets on my Ultimate Darkstar. I used a 38mm coupler tube to shape them. I think the fillets came out really well.



Here are the two together before tip-to-tip. As you can see, the booster section of Scylla is a few inches longer. This is because I wanted a bit of extra room for more shock cord and the RF tracker. Scylla will only end up being about 1.5" longer than Charybdis as it uses a 1" vent bad versus a 3" vent band like Charybdis (Hey, I used what I had).



I got my Cotronics order in the mail the other day, so I was ready to do the tip-to-tip. I cut out all of the pieces of carbon cloth needed to do the job. I decided to go with 4 layers of carbon. I initially wanted to go with 5, but with a 30 minute working time I was concerned that it would start to set up before I started pulling vacuum, and I'm glad I did it the way that I did.



With my dad as an extra set of hands, we went to work getting it together. It went together well, but after I was done initially sealing the bag, I found that I had run out of seal tape. So to seal the leaks, we had to use Manny patented "Ghetto Bagging", using duct tape and rolling the bag over itself. It did work as we were able to get it to seal well and pump up to 20 in. It looks like there isn't much epoxy being absorbed by the breather, and that's because I didn't use much epoxy in the first place.



This morning, I pulled this thing out of the bag. It isn't quite as nice as I was hoping it would be, but it's still acceptable in my book. It has a couple wrinkles, but nothing that some sanding and filling can't fix.



I still have a ton of work to do in the next 5 days before I leave for Black Rock, but I think I can get it done.

Manny

What type of nose cone are you using?

Pretty cool build btw.

MarkH said:

What type of nose cone are you using?

Pretty cool build btw.

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I'm using a filament wound 5:1 Von Kàrmàn nose cone sold by Wildman, and have a custom aluminum tip with a long shoulder on it.

Aksrockets and I are at the world famous Bruno's country club in Gerlach, Nevada ready to go to Aeronaut in the morning.

Manny