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Old Apr 08, 2013, 06:13 PM
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clipper's Avatar
United States, CA, Lake Forest
Joined Sep 2005
140 Posts
Question
Bungee launched, air start R/C Rocket glider

I have a sctrah built R/C rocket glider wing that is a lot easier to to bungee launch and then airstart the rocket motor than launching from the ground!

I can hand launch but the rocket club wants the Rocket Glider remotely released. Dose anyone have some ideas on the release? I'm thinking of a block with a hole and peg that is inserted to the block and glider. To release, the peg is pulled by a cord. Any Ideas, any direct experience with this? I've built a launch platform.

Thanks, Eric
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Old Apr 09, 2013, 10:31 AM
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United States, VA, Winchester
Joined Aug 2005
56 Posts
Tie the bungee back with some string and then cut the string with an Estes igniter?
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Old Apr 09, 2013, 05:07 PM
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X30PILOT's Avatar
Joined Aug 2007
448 Posts
Hi Eric,

A couple of things come to mind here. The EDF guys often use a bungee launch system with a pedal. You should be able to modify this to a remote system.
The second issue would be your need to do this. It really depends on if you are launching a rocket powered glider or a glider with rocket assist. I know this sounds silly but the rocket powered glider falls under NAR or TRA rules. The rocket assist falls under AMA rules. NAR or TRA requires a remote launch system. The AMA does not. The AMA does limit you to the use of G motors. The important thing is to make sure that you dont set off the motor in your face!

Have fun with it and fly safe.

X30
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Old Apr 15, 2013, 04:24 AM
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clipper's Avatar
United States, CA, Lake Forest
Joined Sep 2005
140 Posts
R/C Rocket Glider

The R/C field I fly at already has a lot of restrictions, I'm not even going to try there. With he Rocket club, its a mixed bag. The officers are luke warm, the general members like it. So the remote launcher is a requirement. I'm going to settle an asimple pull-cord release for now. They may want to beable to release R/C RG by the LCO, which means a pyro or solenoid run off the 12V system. What info do you have on the petal release, that would free up may hands!



Quote:
Originally Posted by X30PILOT View Post
Hi Eric,

A couple of things come to mind here. The EDF guys often use a bungee launch system with a pedal. You should be able to modify this to a remote system.
The second issue would be your need to do this. It really depends on if you are launching a rocket powered glider or a glider with rocket assist. I know this sounds silly but the rocket powered glider falls under NAR or TRA rules. The rocket assist falls under AMA rules. NAR or TRA requires a remote launch system. The AMA does not. The AMA does limit you to the use of G motors. The important thing is to make sure that you dont set off the motor in your face!

Have fun with it and fly safe.

X30
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Old Apr 22, 2013, 04:29 PM
aka: A.Roger Wilfong
gnofliwr's Avatar
Novi, Michigan, United States
Joined Jan 2001
2,550 Posts
I'm unclear on what you're trying to do.

1) Bungee launch a glide. I do this with a HiStart (essentially a bungee launch), but I just launch it the same a with a a winch - there's typically more than enough time to get on the sticks before the glider gets out of sorts. I do use a "launcher" with efs and other small, fast planes. I find it difficult to throw and get on the sticks fast enough to avoid an "unplanned" landing. The "launcher" was basically from plans here on RCG (a search for "buhgee launcher" will get it). It's got a foot pedal to launch.

2) Air-starting a motor. You can so this with a relay circuit or microswitch connected to an extra servo running off of an extra channel. Use a seperate battery from the radio system as the drain some ignitors may brown-out your radio system as jsut the instant when you need it.

3) Foot pedal rocket launch controller. These are frequently used by RC/RG pilots so they can have both hands on the Tx while launching from a glider tower. I use one that consists of a foot switch, a automotive relay, a 1/4" phone plug safety interock and a Sonalert for continuity. I power it off of a 4 cell A123 flight battery.

Honestly, the hairriest part of launching an RCRG, is the first 5 feet out of the tower. In my exerience, you need to be ready to apply a little up to counteract the initial kick trying to pitch the nose down as it clears the tower. After it's into the sustainer, you just hold on and keep it pointing up until burn out.

WRT AMA/NAR/TRA. All three provide coverage for model rockets - including RC/RG. In fact, there is cooperation between AMA and NAR on the internats stage. AMA is the FAI representative for model aviation (and space modeling) in the US - so you get your FAI license through AMA. This includes S8 (RC/RG).

From a regulatory stand point in the US, models rockets are defined as weighing less than 1500 grams and with no more than 124 grams of propellant. Until recently NAR (and I beleive TRA) model rocket motors were limited to 62.5 grams of propellant (which essentially limited the motors to 130 N-S - a mid range G). That was recently changed to allow single motors with 125 grams of propellant to be considered "legal" as model rocket motors by NAR (and I believe TRA) - this would be a mid-range H. The 62.5 gram G motor is still the law of the land as far as the Consumer Product Safety Commission is concerned. Larger motors are classed as "hazardous" by CPSC and can only be sold to adults 18 or older.

AMA does not have a high powered rocket program (essentially H and above) - NAR and TRA do, but require user testing and certification at the appropriate level to buy larger motors. But this has nothing to do with the plan form of the rocket.

I personally have flown RC/RG at several AMA club fields and as demos at AMA sanctioned air shows.

- Roger
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