G-Dual Deploy

[AKVP]

Hello All-

Okay, I have today off and I thought I would post a thread I have been wanting to post for some time. I do not know if this is a topic that has been talked about before but I thought I would post my take on it. Also, I have been to many launches and I do not see anybody else doing this. I know of only two others.

The topic is dual deploy in G powered rockets. WHY? you ask. Well, many folks have access to high power fields only after the crops are off (me). Also, many club launches are class one and under fields. If any of you were at NARAM 55, you know my home field (MTMA) can only support model and mid power launches. So, I though I would take it "to the limit" and have some fun challenging myself to "fly the field" while having all the bells and whistles of high power. The folks in the rocketry community who know me, know I like to make electronics bays...I always try to make them more simple, serviceable and "clean". The G-dual deploy rocket made me also make them LIGHT! and strong. Also, I know there are options out there like the Feather weight products. These product are superb! However, this post is for traditional sleds designed for the entry level flyer with parts from the "hardware store"...that kind of thing.

I wish I had gotten into dual deploy before I did my L1. I would have been more prepared and comfortable when I finally made a high power rocket with electronics. This thread serves to maybe inspire others in the mid power range of rocketry to expand your experience and fun in this range. I know many have done this before, but it is also fun to see what YOUR ideas are for making light, compact avionics bays from common electronics.

PLEASE NOTE: I am speaking/writing on a very specific range/class of rocket. it is 1) under 1500 grams LOADED 2) Uses a G class motor (ones that are not considered G-HP like the SU G75-M). However, I DO, and have often launched these rockets on class 1 HP motors like the H128 and H180. Again, the main point of this is to help new mid-power folks get into electronics without going HP and those of us who are L1 and above have "high power" style rockets and launches when we don't have a field that can accommodate bigger rockets.

ALL the things I list here have been tested and "work for me" I will never say my idea(s) are better that "x-y-z" But I would love to see and hear your ideas.

Update: After typing for over an hour, I tried to post this thread and it said I "needed to log in" I WAS logged in! over half of this was LOST even though it was "auto saved". Now I have to Re-type this! So, I guess I will try and give you the main points!

1) The Rocket:

a) Weight is the enemy! I use 2.56" LOC airframe and Aerotech nose cones. LOC 2" airframes are really 54mm motor tubes and are heavy. Also, the nose cones from LOC are much heavier that the ones used by Aerotech. If you want to use 2" airframe, use Semroc H tubes or even Apogee, thin wall tubes and cones.

b) I use friction fit with tape and not shear pins for my main. Remember we are not going to 6000 feet here. Tape works great with practice. Also if you use balsa cones and/or apogee/Aerotech cones....these usually cant cut the 2/56 pins.

c) I also use surface mount bass wood fins 1/8th thick (I can just hear you all saying WHAT!?). Bass wood is light, strong and works great if you cut your fins with the wood grain going in the proper direction. I also sand the life out of my airframes where I glue the fins on...this makes the bond very strong.

d) Use very little epoxy! it is heavy. I use epoxy only on my motor tube/rings, fin fillets and shock cord mount. Wood glue is good stuff.

e) Use an Estes Ps-II motor retainer...very strong and light for these purposes.

f) I say use buttons instead of lugs. That was if you do launch your rocket on an H, it will be safer, and you wont get rod whip.

2) The electronics bay:

a) If you are new....go to a launch and look at other peoples electronics bays. Ask questions, take notes/photos, no question is to simple or dumb. Think outside the box if you are not new to this. There are thousands of way to do electronics bays!

b) When you make yours, keep it simple and clean. Don't over think it. Make as few breaks in your electrical connections as possible. More connections the more chances they will fail. learn to solder!

c) The way I made mine for these rockets.....

I used 6/32 all thread....YUP it is strong enough! Remember this is not a big high power rocket that is over 5lbs. This is a model rocket with some bells and whistles. A guy in my club uses 4/40 all thread on his BT-60 dual deploy rockets!

- I also used 1/8th thick ply bulkheads on my bays. (GASP! Wait!! hear me out!...) I used 5 ply AIRCRAFT ply I got from Barry at LOC the 3 ply stuff you get from Hobby lobby is not good for this! use the light ply from Hobby Lobby for your sled. I also soak my bulkheads in THIN CA and let dry. This makes them even stronger.

- Don't use the LOC stiffy (again...model rocket) it is heavy. I cut 1/2" off each end of the stiffy and used each ring as a stop/lip for the bulk heads. It also gives you more room inside.

- I used small T-nuts in each bulkhead and then screwed in my eye bolt into that for my attachment points for my shock cords.

Okay I am afraid I am going to lose my post before I post it again.... I will continue this by posting another rite after this one. It will have photos and more info, plus a link to a video of one of my rockets.

To be continued......

Peace

 

[AKVP]

Okay....I am sorry for all the type-O's in my first post. I was frantic and afraid I would lose it again!

I see now there is a lot to say and mention on this topic. I have had just as much fun with G-dual deploy and I have had on my larger rockets. WHY? for me it is a challenge to build light and strong. When you don't have all the power you want for your rocket at your figure tips, you are forced to improvise! I have made a flight to over 1700 feet on a G80 dual deploy...that is high for our field (MTMA). All you high power folks out there....I say it is harder than you think! and to all the newbies, I say you can do this...You will also learn a lot and have tons of practice (and have a ton of fun) using a $10 reload rather than a $20+ reload.

A guy in my local club is the master at this. He makes full dual deploy rockets using BT-60 tubes. He launches on F40's! with more glorious flights on G64's....very cool. If you can build an Estes Pro-Series II rocket and launch it at your local park, club or field...why not try dual deploy for a closer recovery!

I would love to see other people's ideas on building a small, light and strong avionics bay. My friend and I cant be the only ones. I hope this post sparks input and discussion. I am surprised that I don't see this more at the launches I go to. My goal is 1500 feet on a G64 using dual deploy....it is harder that you think. the closest I got was 1345 feet...

Also back to some ideas...

Energizer makes a 9V advanced Lithium battery...It is VERY light! much lighter than a standard 9V. It also works great in colder weather.

Below are some photos of my latest "G" avionics bay and two photos of my G-Dual deploy rockets!

 

[AKVP]

Okay-

Last one for now....here is a link to a YouTube video of my first G-powered Dual Deploy rocket. This is made from Apogee Components BT-70 tubes, Apogee Cone, surface mounted bass wood fins (1/8th). The avionics bay has 6/32 all thread, and 1/8th inch ply bulk plates....the only epoxy on the whole rocket is the fin fillets, motor tube and on the shock cord mount. It is very light. I launch it at MTMA launces on G80's, G64's and G76's. It has 20+ flights.

Last year I tried it on an H128.... the video is below!!

It can be done.....I say give it a try (G dual deploy). By the time you go for your L1 you will be a pro at it!!

The link: https://www.youtube.com/watch?v=jTZx9coeSgc

Have fun-Fly safe.

 

[Area66]

........ My goal is 1500 feet on a G64 using dual deploy....it is harder that you think. the closest I got was 1345 feet...

..

you choose the wrong motor the AT G64 is only 110 Newtons, the Cesaroni G54 come with 159 Newtons

 

[rbeard2]

Hey Andrew, Big Ron here from TORC 703. I too have a G-powered, dual deploy rocket that I flew this spring at our club launch. It is roughly BT-80 in diameter and made from 2 Christmas Candy tubes. I think I called it the "Caramel Cream Warhead". I had a near-successful launch using an Aerotech 29/40-120 reload case with a G76G Mojave Green reload. I built the motor the same as always, (smoke delay charge in place) and just left out the ejection charge. Instead I just put a little piece of masking tape over the ejction charge hole. I had an Perfectflite Strattologger on board and the primary charge set to separate the rocket at apogee (no drogue) then the secondary charge to pop the chute at 500 ft.

The flight up was great and I had no problems at all with that motor set-up. This means that you could load an "F" or even an "E" with the 29mm RMS, provided you kept the weight down and had enough room for the electronics. The same could even be said of Estes black powder "booster" motors like the D12-0, C6-0, B6-0 and even the micro sized A10-0T (wow you just gave me a great idea!)

The only problem I had with my maiden flight was when the primary charge blew at apogee, it was a little too much BP forcing the battery to get knocked loose in my home-made tray. Because of this, the secondary charge never blew and my chute did not deploy. one broken fin was the only damage and I have since fixed this and plan to launch again as soon as the corn is out!

To your point though, Yes, I don't see why you have to be constrained to HP rockets to use electronics. Your only restrictions are weight and tube diameter vs. physical size of the electronics and field size.

See you in the Fall!:flyingpig:

 

[AKVP]

Jerry-

I would not say "I choose the wrong motor". That was not my point of the thread...besides, I need more punch at lift off. Unless the G54 has more punch it may not be enough initial thrust....It would be a good motor for my friend though.

Don't know what you are getting at...........

 

[Area66]

I say so because I tough you want to go higher, since I have access to a 1.5 km field I will launch more and more of G-Force DD. last 2 weeks I launch my Arreaux 5 times in DD and the G54 give me H performance; look at the simulation it as the fastest rail exit speed , my Arreaux is 22 oz empty, I check on my 30 oz Initiator and it give a 7:1 trust/pounds ration, more than enough

View attachment 139681



here a launch with a G75J

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View attachment 139679

 

[AKVP]

Jerry-

Dude that is SWEET! Please post photos of how you made an electronics bay for your Arreaux! This is what I am talking about! So far, I have hit a "block" on anything smaller than a 2" rocket. Very cool Jerry. Since I am using 2.56 airframes I need more punch. I also don't own any CTI motors or cases. I love the G64 and set 1500 feet on the G64 as a goal for me now. I would love to see how you set your up.

Hey Ron-

Yea- the first flight I did on my 2" Sand Hawk my apogee charge was so big I tore out my aft bulkhead! That is when I went to the 5 ply AND toned down my BP charge! I have had no problems since. I use G reloads with he longest delay and use the motor as back up. I also use "zip" ties to hold my battery down.

I will try and post better photos of my avionics bay

 

[scsager]

Hello Andrew !

This is a great topic. I agree, you can experiment more and spend less $$ flying F or G motors. I would love to see a build-thread!!

I have tried this myself with a scratch built BT80 bird, and plan to try more. Keeping the weight down is a key. It's easy to overbuild and loose performance or exceed the 1500g "model" rocket limit. I used the inexpensive "Surefire" BT80 tube and a plastic nose from hobbylinc.com Liteply rings and bulkheads and fin material from Balsa Machining Service. This is the 3-ply stuff. Strong and very light. Cut 1/4 inch stop rings for the ebay from the coupler itself. Wood glue - plenty strong up to H or I motor with proper building techniques.

Good tip on the Lithium battery - will have to pick up a few of those to try out.

On the time-out while posting... I hate it when that happens. I usually setup a big post in MS Word, then copy and paste to the forum when I'm ready

 

[AKVP]

Hey all-

Looks like I need a better camera. I am trying to get some good photos of my smaller electronics bay. This is the best I can do:







As you can see I use 4/40 nuts and screws as my charge connectors. I then do NOT use quick links as they can short out the terminals. I tie my Kevlar shock cords rite on the eye bolts, besides it makes things lighter. I also am trying to find a way to use less metal on this design. I even use nylon screws to mount my altimeter and cable/zip ties to hold my battery down. Notice the switch is internal and is held inside a tiny section of pvc tube. This way it is replaceable if it breaks. A copy of this bay was used at a club launch....I got 1600-something but had to use a G80.

Looking for ideas.

 

[Area66]

Hello Andrew !

This is a great topic. I agree, you can experiment more and spend less $$ flying F or G motors. I would love to see a build-thread!!

this is a perfect tread, Sorry if I start on the wrong foot, it was a long text to read for my English. With a G motor I can reach 3000 feet, this is about what the field can hold, ( have a rules that I need a field of 3000 feet to reach 3000 altitude, so it’s twice what the NAR recommend, but I don’t send rocket in the trees) so no need for J or K motors, it's very rewarding to push a G rocket to the limit. I like to keep the flight around 2k, I’m starting a Lower Power club around my place. For the price of a J or K motor , I can build a mid power rocket. Now I will pass my CAR Electronic certification and after I’m gone concentrate more on G power flight on 1.9” and 2.6” rockets. I do also start to play with arduino stuff. I dislike the wood and treaded rod bay, so I will work on finding something better. The wood tray look 1960 not 2014.

Now let's have some fun, here my 2014 high tech system, first the coupler

View attachment 139686

next you can see the remain of the tubing charge that I use saturday

View attachment 139687

and then the altimeter on a crapy piece of wood

View attachment 139688

the battery side

View attachment 139689

and finally you can see it fit tight in an Aerotech 1.9" coupler, so nothing screw

View attachment 139690

so I have work to do to make it look better

 

[AKVP]

Jerry-

Very cool! Nice and compact. I have a few questions.

1) How do you secure your fore and aft bulkheads. 2) Where do you attach your recovery harness? 3) where are the charges? 4) I am a believer in switches, because should you have to remove the rocket from the rail after you arm it, there needs to be a way to turn off your altimeter, so you don't run the risk of having charges go off while holding the rocket, or when removing it from the rail....I guess I am asking, where is the switch? I don't like wires taped to the outside, to me at least its not a clean look.

I am soaking this up. I would love to be able to build something this small...very cool.

Thanks

 

[Area66]

I'm gone make a drawing later, it's hard to explain. For my high power rocket, I use rotary switch to turn off the altimeters and also disconect the charge and shunt them. But on this one, since it don't go on a RSO table or near other peoples with it, I simply use a twist wire outside the rocket, I twist the 2 wires and put tape. this was something make the day before I do the first launch, next one will have switch and a better tray.

 

[Handeman]

Hey all-

Looks like I need a better camera. I am trying to get some good photos of my smaller electronics bay. This is the best I can do:

View attachment 139683

View attachment 139684

View attachment 139685

As you can see I use 4/40 nuts and screws as my charge connectors. I then do NOT use quick links as they can short out the terminals. I tie my Kevlar shock cords rite on the eye bolts, besides it makes things lighter. I also am trying to find a way to use less metal on this design. I even use nylon screws to mount my altimeter and cable/zip ties to hold my battery down. Notice the switch is internal and is held inside a tiny section of pvc tube. This way it is replaceable if it breaks. A copy of this bay was used at a club launch....I got 1600-something but had to use a G80.

Looking for ideas.

I like your thread. I also didn't do electronics until my L1 rocket. I did one flight on a G64 with main at 400 ft. The flight only got to 468 ft, but the apogee and main worked right so my next flight was my L1 cert to 4,200 ft.

A couple of things that might help. Lose the metal charge holders. You can use a 4" strip of duct tape to put the ematch and powder in and close it around them, much lighter. Go with the smallest diameter U-bolts you can find. They may not be much lighter then the eyebolts, but they can't spread on you and it's easier to attach the shock cord. Lose all that wood on the sled. The rods keep the end caps from coming apart and the stuffy tube rings keep them apart. All the sled has to do is hold the battery and electronics, it doesn't need to be structural. Here's a couple pics of my first sled.


As you can see, I overbuilt this. I used 1/4" rods and thick end caps. The ID of the BT was 2" so the ID of the homemade coupler was about 1 7/8". One things that did work well was to put the tubes that the rods went through on opposite sides of the sled. That gave more room for the battery and altimeter.

This was my first av-bay and my first HPR so I learned a lot. If I had to do it again, I would use much thinner sled material, 1/8" rods, 1/4" end caps and lighter u-bolts. Then again that av-bay held up to H to J flights include several I1299N-P at +80G and when a bad battery caused a lawn dart, the altimeter survived the 300 mph impact and is still in use and has had many more successful flights.

I've got a bunch of BTs and MMTs in the rocket scientisting cave, I think I'm going to have to start on a DD I can fly on G motors too.

Great thread!!!!

 

[AKVP]

Handeman-

Wow thanks for the input and reply! The charge holders on my bay are small bullet casings and weigh next to nothing. I thought about the tape/charge method but I am afraid of blowing a hole in my payload if the charge ends up packed next to the airframe wall. Has this ever happened to you? I use the cut bullet casings so the charge is "directed" up and out of the airframe.

I also had to make a double side sled because the overlap of the mounting screws with the battery mount and stuff. I tried a single side sled and I could not make it work. The sled is only 4.2 cm wide and 12 cm long. I used 1/8th launch lugs from Estes for the all thread "conduit". The eye bolts are very tiny, since this is a light model rocket I do not have to worry about it pulling. They are more than strong enough for this purpose. Also, the battery "stops" on either end are made of bass wood.

Per your suggestion, I will try to use less wood, maybe make the sled thinner. I can even drill out holes to lighten it up. I will also consider your charge holder method, although I am scared of blowing a hole in my airframe.

THANKS for your input! THANK YOU!

 

[Area66]

I use a 3/8 aquarium tubing , it never crack or open on the side, I put the electric match on 1 side, put some dog stuff and tape than end with electrical tape, on the other side, I put BP and some dog stuff and then use mastic tape.

 

[AKVP]

Jerry-

That sounds like a good idea...Any photos? just so I know I understand you...(sometimes I am slow on the uptake)

Have you ever had any problems blowing out the airframe?

Thanks for the ideas Jerry and Handeman!

 

[pshooter26]

Small avbay for Estes Vagabond

 

[Area66]

Have you ever had any problems blowing out the airframe?
!

BP is a low explosive, you give it an escape route it will take it, the masking tape is very weak, lot more than the tubing , aside on those small rocket you not supose to use more than .3 g, I use .5g and I have 0 issues.

View attachment 139743

Small avbay for Estes Vagabond

we gone need more detail on this very nice thing

 

[cjp]

Andrew,welcome to the forum.I have an Madcow Striker kit that I wanted to turn into duel deploy.It has been sitting unbuilt in the bag besides my work table for a year now.I'm going to take a vacation day from work and come over when you have time and we can build and visit at the same time.Great thread.You have much to offer to this forum.Carl.

 

[chadrog]

I'm liking this thread as well, lots of good stuff here! If you're interested, (Andrew) I can put some info in regarding my home made 29mm av bay/dual deploy rocket. I can get to it later in the day if you'd like to see it.

 

[AKVP]

Wow!

THANKS for all the input!

Carl! good to see you! Hey come on over anytime! we can build that Madcow kit!

pshooter26-WOW now that is cool! I agree with Jerry.....please post photos of the internal on HOW you made that! THAT is what I am looking for...(small-free standing "unit")

chadrog- Thanks for your post. I would very much like any photos of your 29mm avionics bay...WOW I love all the input here!

THANKS for all the input everybody!

 

[chadrog]

My 29mm dual deploy adventure started at Midwest Power last year, when I botched the assembly of a motor and destroyed a case. The case was shortened to it's full usable length and the process began.


I started by finding an altimeter with the best fit, and built from there - the Perfectflite Hi-Alt 45K was the best candidate. I told myself that this was just a prototype, and would be built cleaner after it was functional, but I got lazy and left it ugly. The "sled" is a (snug fitting to the case) strip of 1/4" plywood. A rough tracing of the altimeters profile was cut through it, and mounting blocks were added.

 

[chadrog]

The power supply is two A23 12v batteries, a slight thinning of the 1/4 sled where they are mounted made for a snug fit. The battery contacts are 3/16" brass tube.


A PCB switch (available from Aerocon Systems) is mounted through the sled and conveniently located for static port access. All wiring is done in the usual way.

 

[chadrog]

Bulkheads were made from 1/16" fiberglass, with PCB terminal blocks from Missileworks. The hardware holding it all together is 6-32, with cardboard igniter tubes to keep the sled from moving. The finished assembly is a nice snug fit in the tube.

 

[chadrog]

First (and only) flight so far of "Rize of the Fenix" was a success. It flew to 3284' on an Aerotech G138. It's dry weight is 1lb. 4.4oz. Next flight will be an H something or other.

Duh, forgot a pic of the complete rocket.

 

[Area66]

this tread start to be very interesting, I just ordered a Madcow 1.6" and a Loc 1.6" ( each at the price of a single K reload , lol ) stay tune

 

[AKVP]

Chadrog-

Holly cow.....Now that is something...THANKS for the photos and tips. I LOVE this. Thanks for sharing your ideas, all of you guys. My mind is working....ideas...ideas...

Very cool

 

[chadrog]

Thanks, it was a fun project.

 

[Dradog]

My goal is 1500 feet on a G64 using dual deploy....it is harder that you think. the closest I got was 1345 feet...

Whats the total weight of that fine looking rocket?