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-   -   jato bottles (http://www.rcuniverse.com/forum/model-rockets-rocketry-492/10268636-jato-bottles.html)

catsmeow1051 01-16-2011 07:01 PM

jato bottles
Hey has anyone usesd rockets to launch a sailplane..? When I was in the service I used to watch over weight aircraft get a jump start with jato rockets on the wings. Any way I am tired of not seeing the prop turning at 20000 rpm and dummy me putting my hand in it.. on my power pod...my bad..? Oh well I guess there are some of us that should stay away from propeller drivin aircraft..Ha Ha Ha ..And to really top the icing on the cake I again stuck my knuckles in my .45 royal pusher with 10/8 a full throtlle .. Slicey Dicey.....smarts abit..looks like a rabbid badger got a hold of the back of my hand.. Oh well,,hope I learn not to keep doing that before I end up with no fingers..! Thanx to any one that answers me...http://www.rcuniverse.com/forum/js/f...ngue_smile.gif

kebuttke 01-21-2011 05:41 AM

RE: jato bottles
It should be possible, but it is something that you would want to fall off or be jettisonable after takeoff. Two motors would be easier to balance, thrust-wise, but you may have a problem getting them to fire at the same time. Depending on the weight of the plane, you may need larger than a D size motor, which in the states requires a license in some areas. Look around on the Internet for the specs of model rocket motors, especially the reloadables, which are machined aluminum tubes and use the same mixture of solid propellant that is used on the space shuttle SRB's. If you would like to discuss more, Pm me, I may be able to present some ideas for jettison

50+AirYears 01-22-2011 01:41 PM

RE: jato bottles
Theere have been a number of rocket assist RC gliders on the market. Might try some of the model rocketry web sites, or the NAR (National Association of Rocketry) website. The RCM plan service, which might still be in existance, had one or two plans. Estes has had a couple planes. I have their Sweet Vee, which uses D or E size motors. Generally, they use rocket motors in D, E, F, or G sizes. Anything above G, you need to get high power certifications to even buy the motors. If you ever watch Mythbusters, they use up to M sized (Biggest available) motors to try to launch full sized cars. They apparently obtain them through someone certified through NAR or Tripoli. I think the first time they tried to verify a car loosing control, using AF JATO, or is it now RATO bottles, they couldn't obtain them. They did get a couple M sized model rocket motors, which apparently each have several times the thrust of the JATO.

I once had a plane manufacurered by the Aerotech company. A nice sleak looking boost glider powered by F or G composite motors. I had to stand about 50' away in order not to lose sight of it during the launch, it accelerated that quickly.

Most motors made for RC are plugged, that is, they do not use the ejection charge most motors have to eject the recovery parachute or streamer, so the end opposite the nozzle is plugged.

I think Flying Models plan service still carries a hybrid from the early 70s that teams a D sized motor with a .19 sized engine.

Some of the English publications had full sized plans in the mags for rocket boost gliders, including a Japanese "Okha", AKA Baka, and a V-1 Buzz Bomb. Might check with Traplet publishers. I think for a while Kalmbach Publishing was the agent for Aviation Model International which had the V-1 and Baka.
If you try one, lightness, low drag, and strength are vital. These motors usually hve a very high initial thrust followed by a drop-off to perhaps 1/3 to 1/2 the initial level, and often are burnt out in less than 6 seconds. I think I remember that the G sized can have an 18 pound thrust for almost a 1/2 second. That can tear weak wings and tail surfaces off real quick.

Generally, the motors in the RC boost gliders are not jettisoned for the flight. Ties in with the AMA guidelines for not dropping parts of the model.

joeshmoe_44883 02-01-2011 04:55 PM

RE: jato bottles
last fall i took a multiplex funjet, put a ducted fan motor on it, chopped off the wingtips and glued on cardboard tubes to house a estes C6-0 in each wingtip. soon as a flip the switch that baby is gone! i had to use a seperate power system to light off the motors. used a real small reciever pack, hooked to a futaba on/off switch, with the output y'd off to go to each motor. i use a micro servo to activate the switch. the cardboard tube is plugged so when the motors are spent, they jettison themselves with there ejection charge. works great.

50+AirYears 02-01-2011 11:29 PM

RE: jato bottles
That just gave me an idea for my old Kyosho T-33. Plane so far has kind of been a dog, but I somewhere have a picture of the P-80 with a pair of ram jets on the wing tips in place of the fuel tanks. Hmm!, a D or E plugged motor on each tip-might be able to get to flying speed a lot quicker.

joeshmoe_44883 02-02-2011 11:13 AM

RE: jato bottles
i think im gonna make some sort of pvc stand that will sit on the ground, and have 2 rails at about a 60* angle. i'll sit the plane on the rails, flip the switch and hold on. spring has to hurry up an get here first tho.

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