Estes Vagabond Dual Deploy

[Neuport]

I built a stock Vagabond a couple of weeks ago with the boys when my oldest son was visiting. This was my first rocket since I was a kid. We had fun with several E9 flights. I decided to build an Estes Ventris and set it up as DD so I thought I would convert the Vagabond as a test bed first to work out the kinks. I ordered a Raven altimeter and scratch built an AV bay. I should have moved the bay further aft for less stability to reduce weather cocking but on the other hand, it will be stable with any engine I could possibly stuff into it.

Since this is my first rocket since childhood and first rocket above C impulse, I would appreciate any comments suggestions. Thx.



For the first flight today I flew it on a plugged E9. Everything went according to plan except a small tack weld on the main chute that increased the descent rate but it was still only 18 f/s and no damage to the airframe. Need more barf or to do a better job of wrapping the nomex around the chute.

Apogee 711 ft; 8" drogue, measured descent rate of 31 f/s
Main at 320 ft; 23.5" main (largest I could cut from an oven bag ), measured descent rate of 18 f/s due to tack weld, was aiming for 14 f/s



AV bay: paper tube from wife's sewing room cut down diameter and length hardened w/ CA, strip of body tube cut from Vagabond, 6-32 all thread rods, 120# test nylon coated steel fishing leader formed into figure 8 to retain split ring for shock cord attachment, Raven 2 altimeter with PowerPerch on a thin ply sled friction fit to tube diameter, bulkheads each made from two plywood discs cut with hole saw and sanded to tube OD and ID and then glued togther to make a stepped plug


Layout: Vagabond fin can with ROUGH orange paint (first coat went on smooth, next coat bubbled terribly from the same can , 1/8" TK shock cord, homemade nomex protectors, split ring connectors, chutes cut from oven bag, 50# braided fishing line for chute suspension lines, forward few inches of BT cutoff and glued to NC to make forward compartment, plywood disc glued into NC and kevlar leader knotted through center hole as anchor with loop and splitring at free end, all kevlar loops formed by threading end back through braid like you would a ski rope

OpenRocket sim file, Raven data file, and .eng file created in TCT with data extracted from Raven data file attached below

 

[Handeman]

Looks great.

My only question would be, do you have enough room in the nose cone and upper tube for all of the recovery gear, and will the chute come out of the nose cone after ejection, or will the charge tend to push it further into the cone and the chute not come out. I would recommend a long ematch and put the charge at the top of the cone.

 

[Neuport]

Thanks for the feedback.

I should have been clearer in the original post. I had already flown it and it worked well except for a small burn on the main chute. I did it exactly as you suggested with long leads on the charges for both apogee and main. Ground testing showed forceful ejection of the chutes.

I think the burn on the main was because everything was stuffed so tightly in the nose cone and the protector couldn't wrap around the chute properly. If I was to do it again I would move the AV bay aft for better balance and to give more room in the nose. I guess I could fix that pretty easily at the cost of the weight for a short coupler and some glue.

Looks great.

My only question would be, do you have enough room in the nose cone and upper tube for all of the recovery gear, and will the chute come out of the nose cone after ejection, or will the charge tend to push it further into the cone and the chute not come out. I would recommend a long ematch and put the charge at the top of the cone.

 

[Jiffycoil]

Very clever. Is it my eyes or is the body tube slightly bowed?

 

[Neuport]

Is it my eyes or is the body tube slightly bowed?

It's just the shop lights casting a funny shadow. The tube is straight and the fins are on straight. Overall, I was happy with the build except for the paint problem. I've built a lot of RC planes in the past and never had a problem like that. I may sand it down and put a better finish on it, or just save the effort for the Ventris I started..

 

[Jiffycoil]

It's a great build.

 

[Neuport]

Thanks.

I should have specified that I cut off the end of the NC and glued a plywood disc several inches into the NC so that the forward compartment is the length of the BT plus 3/4 of the NC. After thinking about it some more, I will cut the main ejection charge in half and ground test that to also help with too much heat during deployment. Now that I know everything works I am hoping to launch next weekend on a zippier E or possibly an F motor. I'll try to capture a video next time.

It's a great build.

 

[Neuport]

Launched again this morning on an EX E56. Came off the pad like a bullet and coasted to apogee at 635 feet. I definately have a draggy airframe, since it simmed at over 900 feet. On the E9 it topped out lower than OR predicted; on the E56 the actual versus simulated altitude difference was much greater due I think to the long coast phase on these fast, high G motors. Does that make sense?

Dual deploy again worked as planned but the main did not unfold. I think there are a couple of reasons for this 1)the plastic I used for the chute is a bit stiff (oven bag) and 2) I packed it very tightly. I will look for some thin light material and I may increase the length of the forward compartment. The good news is that with the drogue open, the rocket in 3 pieces, and the main out but uninflated, there was enough drag that it landed fine without any damage.

 

[Wayco]

Launched again this morning on an EX E56. Came off the pad like a bullet and coasted to apogee at 635 feet. I definately have a draggy airframe, since it simmed at over 900 feet. On the E9 it topped out lower than OR predicted; on the E56 the actual versus simulated altitude difference was much greater due I think to the long coast phase on these fast, high G motors. Does that make sense?

Dual deploy again worked as planned but the main did not unfold. I think there are a couple of reasons for this 1)the plastic I used for the chute is a bit stiff (oven bag) and 2) I packed it very tightly. I will look for some thin light material and I may increase the length of the forward compartment. The good news is that with the drogue open, the rocket in 3 pieces, and the main out but uninflated, there was enough drag that it landed fine without any damage.

Have you weighed your rocket? My wife's Vagabond weighs 6 oz. and flies great on an E9-6 to 1000 ft. She also flies it on an E18-7 hobbyline 24/40. My Rag-a-bond with it's 29mm MMT weighs in at 10 oz. and when I adapted it down for an E9, it also flew great. My favorite load for it is the F22-7 in the hobbyline 29/40-120, slower boost but great visibility to about 2000 ft. Hot loads like your E56 really suffer due to drag increasing exponentially with speed. A slower F12 might give you more altitude if your weight isn't too high for its slower boost. Your rocket must be HEAVY with all the av-bay parts, double recovery stuff and a Raven. I think your weight is more of a factor than a "draggy" airframe, the Vagabonds we fly usually exceed the simulated altitudes predicted. Not sure, but a Top Flight thin mill chute might pack up nicer in that N/C and there's not much weight penalty vs. an oven bag...
I really like your DD design, would like to modify my Rag-a-bond like that when I can afford a Raven....

 

[Neuport]

I can double check the weight tonight but I had weighed when I put together the sim file and it was 231g (about 8.25oz) w/o motor. I don't recall the motor weight but they are not light; a little over 2oz; I'll check that tonight as well.

The stock built rocket flown on the E9's were a few ounces less but w/o an altimeter so I'm not sure how high they were going but I would think around 1000ft. All of the flights, both before and after the modifications, have been very nice flights but with the mods not as high as I would like. I believe you are correct that the high speed drag is causing some of the shortfall. It would be a nice experiment to try slicking it up and keeping everything else the same to see how much difference it makes.

If you do modify yours, I suggest putting the AV bay several inches further aft than I did for better balance and more room for the main chute.

I meant to get video this morning but forgot. I'll try again later this week.

Thanks for the suggestions and compliments.

 

[pshooter26]

Very nice build. Glad to see Vagabond DD.
Built mine more conventional- break in middle. 29 mm motor, glassed fins, used supplied red coupler as av-bay, Raven also. I believe 11 oz with recovery gear --no motor.
A fatty ( get a little heavy handed on fillets and glassing ). Using Thin-mil chute, 24" or 30". Sorry no flight reports, havent gotten around to ground testing

 

[Neuport]

Nice Vagabond pshooter26!

That makes much more sense than what I did. I had no idea what I was doing and I was worried about it being tail heavy with my EX motors so I put it as far forward as possible. I modeled it in OR after the mods and realized I should have put the break further back. I actually could go all the way back to the forward launch lug and still have over 2 caliber stability. I may recut this one just forward of the lug or build another and use the natural break like you did. The kits are only $12 at Hobby Lobby with the coupon.

Are those nylon screws sticking out at about the "O" in Vagabond?

Built mine more conventional- break in middle.

 

[pshooter26]

Thanks. Removable rivets holding Av-bay to payoad. I like how you did yours, might be a little tighter for main chute and harness, but it worked.
As far as "sense", who uses altimeters that cost 10 times the rocket :y:

 

[Neuport]

Exactly! I had the rocket flying so decided modifying it would be the quickest way to test DD. Also, it allows me to use plugged EX motors. Although a simple homemade timer would have worked too for flying plugged motors but this lets me extract the thrust/time curve for the motor in flight giving me more test samples over just the ones from the test stand. I'm sure once I get going the rocket cost will catch up to the altimeter.

One advantage of my far forward CG is that I believe I can stage two motors with out any extra fin area or BT. I may look into that this weekend. The altimeter will allow a programmed airstart e.g. when velocity drops below a preset value or a preset number of seconds after first stage burnout.

As far as "sense", who uses altimeters that cost 10 times the rocket :y:

 

[cerving]

I did this with a Vagabond too, actually a few times. It's a cheap DD testbed. I did two things a little different, first I remade the fins in basswood and made them go through-tube to the motor mount, to handle AT F's. I had the standard paper motor mounts on an early one fail with an E28. I have the motor's ejection charge do the drogue, the electronics just fire the main. 10-11 oz is about as low as you can get it, I get about 1400' on an F24 reload.

 

[Neuport]

I did this with a Vagabond too, actually a few times. It's a cheap DD testbed. I did two things a little different, first I remade the fins in basswood and made them go through-tube to the motor mount, to handle AT F's. I had the standard paper motor mounts on an early one fail with an E28. I have the motor's ejection charge do the drogue, the electronics just fire the main. 10-11 oz is about as low as you can get it, I get about 1400' on an F24 reload.

Nice. Cheap is right at $11. As was pointed out earlier in the thread, I have $150 worth of electronics on an $11 rocket. This was my preferred setup in RC as well. A really cheap, disposable airframe with nice electronics on board. Can't be beat for learning.

 

[Barracuda]

I just started on my first vagabond ,I was trying to see what all the hoopla was about:eyeroll:.Well first it was a lot longer than I thought:shock: and second..man that nose cone:surprised:.Might try my first build thread with it:lol:

 

[Neuport]

Go for it! I think with the hobby lobby coupon it is the best deal in LPR with the large size, great looks, and super flying. I keep thinking I should build another. Start a thread and I'll probably join you.

 

[pick1e]

Newb questions here. Sounds like the nose cone tube is friction fit to the AV bay/coupler. Isn't there a risk of the momentum of the nose cone section pulling away from the AV bay once the tether becomes taught? I know shear pins are used on larger rockets and wondered if there was a similar technique for smaller airframes. Is there a rule of thumb of when you graduate to shear pins?

 

[Neuport]

Isn't there a risk of the momentum of the nose cone section pulling away from the AV bay once the tether becomes taught?

Yes

I know shear pins are used on larger rockets and wondered if there was a similar technique for smaller airframes.

I think you could just use smaller shear pins e.g. with square styrene from the hobby store. I bought some but have not tried it yet. I'm no expert, this project was what I used to teach myself dual deploy. But, I think a couple of things mitigate against shear pins in this case.

1. I don't fly it that high to begin with (<1000') so it is really a practice exercise. No real harm if the main comes out early.
2. The nose cone is light compared to larger rockets so there is not much momentum to deal with. Friction fit seems to work just fine.

If you do use shear pins with a paper rocket you will want to harden the holes at least with CA. On my Ventris build I also put brass shim stock on the NC. However, I have not tested or flown with shear pins on the Ventris yet. I ran out of time and actually finished it at Airfest so I flew it friction fit. The first flight was fine. The second I had an early main but it was because of a leak in the AV bay and the altimeter sensed a lower altitude due to a pressure spike and fired the main immediately after the apogee charge. Not an issue with the friction fit.

 

[pick1e]

Yes

I think you could just use smaller shear pins e.g. with square styrene from the hobby store. I bought some but have not tried it yet. I'm no expert, this project was what I used to teach myself dual deploy. But, I think a couple of things mitigate against shear pins in this case.

1. I don't fly it that high to begin with (<1000') so it is really a practice exercise. No real harm if the main comes out early.
2. The nose cone is light compared to larger rockets so there is not much momentum to deal with. Friction fit seems to work just fine.

If you do use shear pins with a paper rocket you will want to harden the holes at least with CA. On my Ventris build I also put brass shim stock on the NC. However, I have not tested or flown with shear pins on the Ventris yet. I ran out of time and actually finished it at Airfest so I flew it friction fit. The first flight was fine. The second I had an early main but it was because of a leak in the AV bay and the altimeter sensed a lower altitude due to a pressure spike and fired the main immediately after the apogee charge. Not an issue with the friction fit.

I see. Thanks for the info. I also have a Ventris I've flown only on F24's. I have a G80 for it but I'd like to stick my DIY timer in there and make it DD so I get it back I have another Vagabond in the works and I'd like to use DD with that one too (its predecessor had only flown on E9's). Now to find me some BP...

 

[Neuport]

If you decide to setup a Vagabond DD consider breaking the tube further aft than I did to give yourself more room up front for the main.