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  #1  
Old 09-17-2018, 12:33 AM
Bogdan Bogdan is offline
 
Join Date: May 2018
Location: Essex
Posts: 6
Default RV12is BRS

Hi everyone. This topic was started 5 years ago and with your permission I will start it again. Having a 12is project, Ií m wondering if anyone tried to fit a rescue parachute in. If I remember correctly someone did all the calculations and weights but nothing solid at the end. My question is, can be done? Thank you
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  #2  
Old 09-18-2018, 08:50 AM
Major-Tom Major-Tom is offline
 
Join Date: Jul 2018
Location: Templin (Germany)
Posts: 9
Default

A BRS parachute will be definitely be a part of my RV-12. But like all builders I start with the empennage kit, which is on its long way. So I have no solid facts yet. What I have is direct contact to BRS Germany and an engineer, they often work with and the determination to make it work.

The right size chute for the weight and speed range is the BRS-1350. Its over all weight, including rocket and holder is about 13kg . The dimensions of the small package containing the vacuumed chute are hight=410 mm, wide=250 mm, hight=150 mm, weight 9,7kg. This should easily fit into the baggage compartment. The rocket could go into the baggage compartment. But it is not a too nice experience to have it go off just behind your back, like a friend told me first hand. It is loud and fills the cockpit with steam. Yes, just steam, no fire and smoke. These rockets don't use gun powder. Maybe place it on the rearward wall of the baggage compartment and the chute inward. Of course, hiding the lines is not so easy on a low wing aircraft.
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  #3  
Old 09-18-2018, 02:36 PM
Jamesey Jamesey is offline
 
Join Date: Feb 2008
Location: Hartlepool, England
Posts: 161
Default BRS

Not aware of any steam powered rockets. They all have some kind of combustible propellant. Not sure Iíd want that next to an internal fuel tank. Iím prepared to stand corrected.
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  #4  
Old 09-18-2018, 03:17 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,749
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At 13 Kg, that is already 28 lbs.
I have enough experience with BRS systems to know that the 28 lbs is probably not enough to account for the weight of the risers and other add ons that will be required to connect the chute to the aircraft.
By the time you add that, the total added weight will have eaten up a good majority of the available baggage payload.
If the aircraft occupants will always be on the lighter side as far as human adults go, then the loss of payload weight might not be too big of an issue, but unless an installation can be designed that would mount the canister in the baggage area the C.G. shift induced by the installation would likely make the baggage area just about unusable, regardless of the weight of the bodies in the seats.

All of the BRS systems I have seen use rockets with a solid fuel propellant. Not what I would want firing off from inside the passenger compartment in an airplane I was flying....
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Last edited by rvbuilder2002 : 09-18-2018 at 03:19 PM.
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  #5  
Old 09-18-2018, 07:38 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,320
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I think some ultralights use a compressed gas system. I considered a BRS, but I concluded the gas tank would be an issue due to the harness. I was concerned that any harness attached to the main spars could rupture the tank on deployment.
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  #6  
Old 09-18-2018, 08:24 PM
larosta larosta is offline
 
Join Date: Dec 2010
Location: Redlands, CA
Posts: 137
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Here is a paper that may be of interest to anyone considering a BRS. It primarily addresses the application of a BRS to a hang glider but much of it may be applicable to a light experimental aircraft as well. The author, Betty Rothman, is a very experienced and respected Hang Glider and Ultralight flyer and previously owned a parachute and harness manyfactruirn company whose products are still making "saves".

http://www.highenergysports.com/yaho...sy.1171338.htm
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  #7  
Old 09-19-2018, 02:48 AM
Major-Tom Major-Tom is offline
 
Join Date: Jul 2018
Location: Templin (Germany)
Posts: 9
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Thank you for the input. It would be great to share some thoughts on the technical details, without the conversation drifting off to fast in the direction of "chutes are just for bad pilots or badly constructed planes". There are good arguments pro and con. Lets just for sake of a good brainstorming suppose, for some people to have a rescue system is worth the effort.

Quote:
Not what I would want firing off from inside the passenger compartment in an airplane I was flying....
I am sorry for writing down the rocket motor - steam - smoke topic so little precise. What I meant was, this not the type of black powder driven firework rocket. Sure, a BRS rocket uses a solid chemical propellant, but it is different. The chute companies homepages surely will have the information in english. (I cant describe better) Anyway, of course it is best to keep the rocket out of the cabin. It is not nice the other way, but the guy, with the rescue system inside the cabin also told me, the cabin cleared in seconds.

Quote:
If the aircraft occupants will always be on the lighter side as far as human adults go, then the loss of payload weight might not be too big of an issue, but unless an installation can be designed that would mount the canister in the baggage area the C.G. shift induced by the installation would likely make the baggage area just about unusable, regardless of the weight of the bodies in the seats.
Very good point. You are absolutely right, the main weight of the system needs to be near C.G. Best place seems to be the baggage compartment, The package is not big, so there is not much wasted space, just lost payload (what is bad enough, but if you want something you have to except its downsides).

Quote:
I considered a BRS, but I concluded the gas tank would be an issue due to the harness. I was concerned that any harness attached to the main spars could rupture the tank on deployment.
At this point, attaching the harnesses seems the biggest problem to me. Of course the main spar is the strongest part of the plane. But I hope other good attachment points a little forward and rearward can be found. Four such points must be found. The plane must hang with a slight nose down attitude. Can someone provide the distance of the main spar to the C.G. range?
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  #8  
Old 09-19-2018, 06:44 AM
Bogdan Bogdan is offline
 
Join Date: May 2018
Location: Essex
Posts: 6
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Thank you all for your interest and discussion on this topic. Iíll speak with an engineer myself soon and asap I will post the outcome. I feel responsible somehow to add one more thing; when I started the topic, I wasnít thinking about bad pilots vs good pilots and bad constructed airplanes vs good ones. I was thinking about structural failure for exampleor flying over forests/water and when you intend to fly with your 5 years old child (because heís so in love with airplanes), being a good pilot or having the best airplane, is never enough to feel and to keep him safe- letís try to find out if we can improve a project which is already amazing. Thank you again for your support
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  #9  
Old 09-19-2018, 10:33 AM
Tommy123 Tommy123 is offline
 
Join Date: Jul 2018
Location: Naples fl
Posts: 46
Default Jump

If a BRS is deployed the airplane is most likely going to be a total loss. Instead of spending all the time and money trying to install a BRS why not just buy a couple of bail out parachutes?
If youíre terrified of jumping out, you will change your mind when facing certain death.
It also seems that BSR systems tend to make people get themselves into situations that they would avoid without one. The guy that took off VFR into a 200 foot ceiling in a cirrus comes to mind.
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  #10  
Old 09-19-2018, 11:11 AM
alexe alexe is offline
 
Join Date: May 2013
Location: Temecula, CA
Posts: 247
Default

Tommy123, I think you might find it impossible to jump out considering the RV-12ís tilt up canopy.
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