54mm min dia Build Thread

but... I wouldnt use a heavy bulky 3/8" or even 1/4" G10 fin when I could get some 1/16" or 3/32" G10 and do a few layers of CF (much lower drag and much lighter)...

You probably wouldn't need a 1/4" G10 fin though. I know 3/32" would hold up to mach just fine (though mach 2 would be pushing it a bit), and 1/8" would be more than enough for any 54mm md bird. G10 is stronger than a lot of people give it credit for.

I was using your mach 4 example... a mach 4 G10 fin equiped rocket would need atleast a 5/32" fin, maybe even a 1/4.... depending on attachment methods.

I was able to test the motor a couple of weeks ago out at Black Rock. The test went well. I did crack the nozzle (made two more yesterday) It was weird being out at Black Rock and seeing a lake out there. I did fly a couple of rockets on EX day, a 38mm min dia rocket to 10,797' and a 54mm min dia rocket to 19,020'
It looks like I will fly this project at Aeronaut Aug 4-6.
Tony

What motor did the 19k in the 54mm tony ?

It's a formula called swamp gas. It's a low solids(75%)l ow Isp (179) formula. The flame is always detached and it burns kind of rough and belches black smoke sometimes. If your looking for something with mach diamonds or a very pretty flame, this is not the formula. It does burns fairly long and I think that's why I get good altitude out of it. I've been using it in Aerotech (Dr. Rocket) hardware. That fight was with the 54/2560 case. Swamp gas in this case works out to a K530 and a 4 sec burn. I've flown the same rocket on K700 and got 19,952 and with the K1275 it got 19.936'.
Tony

excuse me if this was already said somewhere in this thread but what did you use for your drogue and main harness? Did you use a drogue? Most importantly, what did you use for the main chute? I have the option of a $45 high quality hemispherical (nice chute but its heavy and doesnt pack ultra tight) or i can get a custom RR8Q (rocket rage quantom chute, will take 5 pounds down at 15 fps). It is one of his new ultra light tight packing ones... problem is he says the labor is the same as a larger chute so he is charging $100 and I think that is a bit much, considering thats nearly what I spent for a chute last year that can take a 35 pound bird down...

It's drougless and the recovery cord is kevlar 'mule tape' rated at 1800#I got it at a launch..I could never find a source for it. I have 4 -'black electrical tape' break points in it. The chute is home made and I used kevlar shoe laces on it..You have to think out side the box some times when your building these min dia rockets..I like to figure out new ways of doing or using things..Mule tape, Kevalr shoe laces, spent single use motor cases as couplers/electronics bays, old camp tents made in to parachutes. I've flown my L3 rocket about 8 times now..every time I see it with the chute laying out...I think "that sure looks like my old family tent"..becasue it is!

Tony

I will look into making my own chute... I am going to talk to rocketrage... ron says he can make a competition (ultra light and tight packing) chute that will take my bird down nice and slow, but for $100... if I cant get him to take that down a bit I will look into seeing if he can through in a few things, maybe a D-bag or nomex chute protector... because $100 is a lot for such a small chute. I may see what a smaller chute will cost because I asked for one that will take the 5 pound bird down at 15-17FPS and I am sure considering how its built that it can take a bit more speed... I am just worried because I am doing most of the flying on a hard dry lakebed.

forget to add one quick question... or two... do you recall how much kevlar you had for your drogue and main harness? Your kevlar seems a bit stronger then mine (rated somewhere between 600-800 pounds) but I am not worried about the kevlar breaking, its the attachment points that I am worried about, because of the lack of stretch that kevlar has. I am not 100% sure on how much I currently have but I am about to go check... it isnt much though. You talked about the electric tape, is there a technique using tape to help absorb the energy so the kevlar doesnt have to take all of it? EDIT: 1/8" tubular kevlar, 21' for the drogue and 15' for the main... I now regret getting it a little on the short side but I didnt realize how tightly it packs... so if I can make this amount work that would be great.

Attached is a photo of the 'black electrical tape' break points. They act as a shock absorber for the recovery system. I've broken kevlar in the past (no stretch) but not since I've been using break points. I just got done doing the ground tests. I have 17 feet for the drogue in a 2" long space. One gram in surgical tubing broke 3-2/56 nylon shear pins and the single wrap break point. For the main I have 10 feet and .75 grams did the trick there. I was also able to ground test my 29mm min dia. I'm using the AT 29/360 case and ejecting the motor out the back of the rocket..pulling the chute with it. .75 grams was a tad much but everything deployed as planned and nothing was burned..
Tony

The pictures help a lot, but I still cant really understand it, why do the loops all have differnet numbers of tape wraps? How tight is the tape wraped? Why electrical tape? Wow, 17' and 10'... i think my 21' and 15' should work fine then. I am not that worried about the kevlar breaking (but I will look into the breaking strength for it), I was worried about attachment point damage. But from what you are saying I guess this technique will help out a lot. What considerations are you taking into high altitude's and BP charges? I dont know what your rocket will do but on the EX L1200WR I may put in my bird rocksim says 24,000'... that is one of the things I havent researched yet so I am curious to see what you did. I would normally just make the charge in the corner of a plastic baggy, I am hoping I wont have to do anything much more costly then that.

If you had the same number of wraps on each set..there would not be as much of a 'gradual stop'. Do some experiments with it tied to something and see how it works..as far as how tight..as tight as you can get it. With your recovery being 6-800# I would be a bit concerned...only becasue I've broke 1800# stuff before. When flying over 20K you should begin to consider BP charge containemt issues. Yes those 'hammer motors' do eat into the altitude.
Tony

I have some 1/4" kevlar (very strong stuff, as I am told) (tubular kevlar that is) but it is very bulky... but i could use it if needed. The 1/8" TK i was planning on using packs unbelievably tightly and is very light. Its hard to believe you need 1800 pounds of strength for something this weight, are you telling me you have 1800 pound quick links? I use 5/16" quick links on a 35 pound bird (believe they are rated at 1760 pounds) so I have no clue why that kind of strength would be needed for a rocket this weight. EDIT: I am also curious why in the pic I see a kevlar harness protector, over a kevlar harness. I plan on putting a small nomex chute protector into the drogue and main bay but I dont know how necessarry a harness protector is...

If your flight goes straight up..stops...deploys at apogee...floats down slowly...and pops the main..this would be the best case scenario..I know a guy that uses plastic grocery bags for parachutes on 3" rockets..they work most of the time for him..those flights that go perfect. I've also seen "ballistic' drogues shreaded to bits..so I design my recovery system some where in between those extremes. It all depends on how much room I have...I like this 1800# kevlar..it packs fairly small and is pretty forgiving. But I have broken it. I can tie my 1800# kevlar to my truck and a screw driver to the other end and break it fairly easy by just jerking on it with my arms. See attached photo..Kevlar does not like to be shock loaded. I've seen 2" kevlar snap on a 4" rocket..Do I plan on shock loading it? I hope not but just in case my flight is not perfect..I have some built in safe guards..1800# kevlar, Break points..etc. I do not use quick links. I tie to my recovery points directly..eliminating extra weight and another failure point. I put nomex on that kevlar to help protect it from my ejection charges...yes kevlar is fire proof...but repeated use makes it a failure point...and that attachment point is a pain in the butt to reach.
So your planning on flying one of James L1200WR..it's going to be a fast flight no doubt! If it weather cocks just a bit..at what speed is it going to deploy at? What is the weight of a 10 grain 54mm case..will this shock load your recovery system? All I'm trying to do is point out things that I take into consideration when I design a recovery system. No, I can't design it to take the ultimate abuse. But I can design it to absorb some of the not so perfect deployments..
Tony

It isnt going to be ultra light (the 10 grain casing...) but how much heavier is that then the load for yours? Also, what does speed and weather cocking have to do with anything about deployment at apogee? It will slowly arch and then deploy. Also, I could add a 4000 pound rated kevlar harness but then my attachment points would still be very stressed... Thanks for the help though Tony...

I was able to fly the rocket this past Friday. It was all loaded up (8.44 pounds) and placed in the tower, and the tower was staked down. The L850 Swamp Gas lit right away. The rocket left the tower pretty violently..(it was later determinded that the tower may have fallen over) The rocket straighten out and the motor burned for 3.5 sec. The rocket had no tracking smoke..(would have taken away from the propellant). I was able to put a Walston in it but only had room for it in the electronics bay and did not have a signal until the main deployed. After about 3 min I got a signal and my buddy and I hopped in my truck and took of in the direction of the signal. We soon lost the signal. (rocket on the ground) but kept on the same course. We found the rocket about 2.5 miles out. The first thing I noticed was that all the clear lacquer had been burnd off and had left an extremly rough surface to the entire rocket. The G-Wiz was blinking out 23,001', which was below what I was predicting. I'm guessing the rough flight out of the tower and the rough finish accounted for the lower altitude. So what now? I'm going to wet sand the entire rocket back to the epoxy/carbon fiber. Use a better tower and fly it again at Balls. (photo to come)
My buddies Mike's rocket Medusa's Wild (2-stage 14 motors) flew on 14 Wimpy Red EX motors. We got 13 of the motors to lite, and all 13 of those worked as planned. We did have a bit of a problem getting the chute all the way out on the booster.....
The 100K group project was cool...Everybody worked on it to get it ready to go. It was a sight to see out on the 1500' pad. Once everything was ready to go. we drove off about 700' and waited for the count down. Once the O-5100 came to life it was amazing to see and feel the power! I've seen a few big motors and this was the best one yet! We had a structual problem with the upper section of the sustainer (mach 1.8) before booster burn out and lost the electronics. The booster continued to 21K where is deployed it's chute and was returned in good condition.
Tony

Max speed? What load will you be using at BALLS? I plan on going to XPRS or BALLS (havent desided yet) and flying my 54mm... it will be tested to mach 1.6 and 2 miles on a K1100T, then the L1200 for mach 2.5 and over 20,000'... Cant wait!

I went with a G-wiz...Once I got the real weight into rocsim it shows mach 2.3. I'm flying the same motor at Balls with an ARTS and just going with a 'wet sanded' rocket to see who much altitude was scrubbed off with the burned off lacquer.
Tony

I will either be at XPRS or BALLS with mine... maybe ill see you out on the playa! My curing oven is finished, i am going to make the airframes tonight/tomorrow and then post cure them whenever I get a chance. A lot of the GPS tracking stuff is starting to show up and the halo rocketry parachute came a few days ago, VERY NICE. On monday I need to call performance hobbies and see if they have any PR couplers and nose cones...

Here is the flight info for this rockets flight at Balls.

Barro Altitude 29,040'
Accel Altitude 25,020'
Averaged Alt 27,030'
Max Velocity 2,245 ft/sec (mach 2)

see attached

Tony

Wow that is very good...29,000'! Thats very good, but I find it strange that the accel alt was lower then barro. Accel alt is basically the distance traveled by the rocket, so if the rocket flew at a 45 degrees angle it may have traveled X amount of feet but its actual altitude was much lower. Did you max out the accelerometer? (did you go over its 50G limit). That would explain a lower accel altitude...

Congrats on a successful flight!

Here is a photo on it's way..

What's up next? Lets see how it goes on a L1550.

Tony

Interestingly, my blacksky altacc 2c always reports a lower accel altitude than the barometric altitude. Doesnt' matter if it's a straight flight or if it weathercocks.....perhaps it's an artifact from the software???

I dont know much about the software specifics but from what I have read about the acceleromic altitude is based on vehicles speed and how long it is at that speed. Accelerometer doesnt know if the rocket is perfectly vertical or not so it is basically the distance traveled by the rocket.

Thats why TRI (and most likely NAR) dont allow acceleromic data for altitude records, barometric is all that they allow.

Originally posted by Tfish
Here is the flight info for this rockets flight at Balls.

Barro Altitude 29,040'
Accel Altitude 25,020'
Averaged Alt 27,030'
Max Velocity 2,245 ft/sec (mach 2)

see attached

Tony

Click to expand...

Well thats a new TRA L research motor altitude record if you want to take it away from David R.