Radio Control Chute Deployment

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
Andrew Leigh
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Joined: Sat Aug 07, 2010 10:10 am

Radio Control Chute Deployment

Post by Andrew Leigh »

Hi,

A friend gave me a RC Transmitter and Receiver. Today I bought a servo for the system.

My problems is that the 4.8V 1300mAh battery pack is well overspec'd for one or two deployments and it weighs 128g which is way excessive in my opinion for a 4l rocket.

What do you boys use as a battery solution?

Cheers
Andrew
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thampson
Current WRA2 Dragster Speed & Distance Record Holder
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Re: Radio Control Chute Deployment

Post by thampson »

Andrew,

You dont so much need that many amps but you do the the volts to get the servo to work. Find the lightest batteries you can that will give you 4.8V.

We use an R/C transmitter on the rocket car and we use a 4 pack of AA batteries and a cradle, but I could probably do it lighter than that if I needed too. Maybe try the small round batteries that go in calculators/watches etc. I know there is a 12V battery that is the size of 1 x AA battery which is made up of a stack of these batteries, just open one and take out the number you need to bring it back to 4.8 or so volts, slightly over is better.

The R/C parachute deployment will work ok, just test the distance of your transmitter to receiver first on the ground. We have tested our AM transmitter at around 200m and it works just fine. We are testing the second channel of our r/c to do a parachute deployment for the car at the moment, so Id be interested in your results.

regards
-todd-
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Andrew Leigh
Advanced Member
Advanced Member
Posts: 39
Joined: Sat Aug 07, 2010 10:10 am

Re: Radio Control Chute Deployment

Post by Andrew Leigh »

OK,

here goes. The first launch on Saturday, the chute failed to deploy. Realised soon enough that the rechargable battery pack in the transmitter had not charged sufficiently to send a signal to the receiver. Think I need a new battery pack.

Charged the battery pack overnight, made a new nose cone and readied for Sunday. Launch 1 was at 80psi and the parachute deployed perfectly, Launch 2 at 90psi and the parachute deployed again and finally at 100psi the parachute deployed yet again. Must confess there was much creaking of the bottles at 100psi, got a little nervous but hey no pain no gain.

A point to note that there were some heart stopping moments as the chute takes some time to deploy and at times you dont think that anything is going to happen but the chute deployed fully about halfway down on all three occasions.

Battery pack held out for the three launches but I do not trust them and will get a new pack.

Copied the parachute deployment system as oulined here http://sites.google.com/site/littlesqui ... te-systems . It is real easy and works very well compliments to the designer.

From a mass perspective it turned out the the battery pack was required for stability of the rocket ...... I think.

My rocket is 4l, connected by a Robinson Coupling having an internal ID of 7.3mm. A total dry mass of 410g and was filled with 1.2l of water. At 100psi my brother and I both estimated that we go 70m, the simulation says we should have got circa 77m so we are in the ball park.

Cheers
Andrew