RE: TwinJet to Rocket Propelled/Ever been done?

RE: TwinJet to Rocket Propelled/Ever been done?
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RE: TwinJet to Rocket Propelled/Ever been done? - 8/23/2006 2:23:42 AM

TheJester

Posts: 76
Joined: 5/6/2006
From: Fairfield, IA, USA
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Yeah, here is the final cut with a closer fly by with a B on it. Still not what I want, but was all I had.

http://www.ratpackinternational.com/rocketwing.mpg

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RE: TwinJet to Rocket Propelled/Ever been done? - 8/23/2006 6:36:44 AM

stupidaso

Posts: 75
Joined: 1/30/2004
From: Hayden, ID, USA
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Cool video.

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RE: TwinJet to Rocket Propelled/Ever been done? - 8/23/2006 6:41:00 AM

stupidaso

Posts: 75
Joined: 1/30/2004
From: Hayden, ID, USA
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I am building a sig wonder, which I am planning to put a rocket motor in. It will have the conventional glow engine up front, with the rocket motor inside the fuselage. As you may know, the wonder has an open rear end.

Do you think this is something that could be done, similar to what you did? I have been into rc planes for about 5 years now, but adding rocket power is a whole new world to me.

I would appreciate any input you could give me.

Thanks,
Stu

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Speed without control is........well......SPEED!

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RE: TwinJet to Rocket Propelled/Ever been done? - 8/23/2006 7:10:38 AM

TheJester

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From: Fairfield, IA, USA
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quote:

ORIGINAL: stupidaso

I am building a sig wonder, which I am planning to put a rocket motor in. It will have the conventional glow engine up front, with the rocket motor inside the fuselage. As you may know, the wonder has an open rear end.

Do you think this is something that could be done, similar to what you did? I have been into rc planes for about 5 years now, but adding rocket power is a whole new world to me.

I would appreciate any input you could give me.

Thanks,
Stu

I don't see why that wouldn't work, but are you going to be about to get to it after you put the rocket in? Depending how big you are going to go, I would say, head to www.apogeerockets.com because they have a wealth of information about rockets, burn times, blah blah blah, and they also have the Rouse reload kits, which I'm using so the rocket casing can stay in place while the reload is the only part that has to be replaced. Also, I would go with the Aerotech Jr Starter Igniters because you can use the power from a 9-volt battery. There's a picture of my "crued" switching method above, but if you want a better picture, just let me know.

Putting the prop on the front with the rocket out the back is something we are getting ready to do to a stryker.
How big of a rocket motor are you going to try and start with?

Having had my first attempt with the twin jet fail, I would point out that you are going to want to find the right ANGLE to put the rocket on in order for it to work properly after ignition. How to do that, is kind of a mystery to me.

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RE: TwinJet to Rocket Propelled/Ever been done? - 8/23/2006 11:50:36 AM

RetroFlight

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Joined: 8/13/2006
From: Atlantic, IA, USA
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I would suggest locating the rocket motor as close to the pitch and yaw centerlines as possible. Right on centerline would be ideal. However if you have to offset it then point the rocket motor centerline at a location midway between the CP and CG locations. If not sure of CP location then aiming slightly ahead of the CG ref. point will usually suffice. The rocket motor thrust line will become more critical as the motor location moves aft from the CG point. And with a rearward location the CG will shift as the motor propellant burns away. So try to balance the model for stabile flight with and without propellant weight. A delta wing is more forgiving in this regard a straight wing design can be a challenge. Straight wings often require nose ballast dump (water) to maintain stability as the motor propellant burns away. As in the case of a ME-163 model. Ideal model would be a delta wing with symmetrical airfoil (non-cambered). Symmetrical airfoils are less disturbed by pitching moments. Camber airfoils will result in a looping powered flight path so if using a cambered airfoil be ready for down elevator right after motor ignition.

Retro

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Post #: 30

RE: TwinJet to Rocket Propelled/Ever been done? - 8/24/2006 3:32:43 AM

stupidaso

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From: Hayden, ID, USA
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I really don't know which motor to start with. I like your idea with a "reloadable motor system". I am still trying to educate mysef on the details of model rocket engines. I am concentrating on building right now. I am reinforcing the spars with carbon fiber straps, and am debating glassing the entire wing.

Thanks for the website, I will check it out
Stu

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RE: TwinJet to Rocket Propelled/Ever been done? - 8/24/2006 3:04:45 PM

rcmaster-RCU

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I just flew my rocket powered stryker creation yesterday. It was a flawless flight and was very stable through the whole thrust period. I wish I was more technologically advanced or else I would post some movies. I wil try and get some pics up very soon.

Alex.

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Post #: 32

RE: TwinJet to Rocket Propelled/Ever been done? - 8/24/2006 3:10:25 PM

rcmaster-RCU

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TheJester,

I just read you are trying a rocket project with a stryker. It is a great platform for a rocket plane. Good luck!

Alex.

(in reply to rcmaster-RCU)

Post #: 33

RE: TwinJet to Rocket Propelled/Ever been done? - 8/24/2006 3:36:54 PM

RetroFlight

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From: Atlantic, IA, USA
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The Stryker is a good planform for conversion to rocket power. Did you fly it with rocket power vertical flight only or did you air start the rocket in flight?

Retro

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Post #: 34

RE: TwinJet to Rocket Propelled/Ever been done? - 8/24/2006 5:47:08 PM

rcmaster-RCU

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I hand launched it then ignited the motor. This took it to maybe 300 feet, then when it came down to about 20 ft in the air, I ignited the other motor and took it up again. I have a two stage set up.

Alex.

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Post #: 35

RE: TwinJet to Rocket Propelled/Ever been done? - 8/25/2006 12:04:16 PM

rcmaster-RCU

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My rocket stryker caught on fire yesterday in mid flight. Completely destroyed it and all of my equipment, but it was a spectacular crash. That foam is very flammable. My guess is that the ejection pulse broke through my fire wall I had to absorb it, and caught the foam on fire and about 65% of the plane was a fireball. The general flight was flawless, very smooth and controlled. Back to the drawing boards.

Alex.

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Post #: 36

RE: TwinJet to Rocket Propelled/Ever been done? - 8/25/2006 2:46:17 PM

RetroFlight

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Joined: 8/13/2006
From: Atlantic, IA, USA
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If using Estes motors A thru C size cut some airframe tubes longer than the motors glue a couple other sections together to join the tubes at the end. And route (vent) the eject charge out away from the planes fuselage. If using "D" size 24mm diameter Estes motors select the Estes "D11-P" and "E9-P" the "P" stands for plugged and does not have an eject charge. Or use the Aerotech composite motors where you just discard the blackpowder charge (or collect it for back-up parachute deployment). If your using Estes "A" thru "C" 18mm motors checkout these 18mm Aerotech composite reloadble motors
http://www.hobbylinc.com/htm/aro/aro91181.htm they pack twice the power in the same size motor as an Estes BP.

How much does a Stryker model cost, who sells them? I might just try one myself, I like the planform with rearward swept wings and long LE strakes. Should fly well with rocket power as the motor(s) are located very near the CG/ CP location. And the LE strakes should form a nice set of vortex flows over the main wings to allow for high AOA flight without stall.

Retro

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Post #: 37

RE: TwinJet to Rocket Propelled/Ever been done? - 8/25/2006 3:15:06 PM

rcmaster-RCU

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I had a curved cavity to absorb and route away the ejection blast, but it wasn't fire proof and strong enough or there wasn't enough room. The Park Zone Stryker replacement wing is very cheap about $25-$30. I have no idea how much the full plane is. Also too the motors with no ejection pulse are more expensive and harder to find. Where can you get F cases and reloads online? I have an Aerotech Phoenix kit I am going to build but it did not come with any motor material.

Alex.

(in reply to RetroFlight)

Post #: 38

RE: TwinJet to Rocket Propelled/Ever been done? - 8/25/2006 4:25:32 PM

RetroFlight

Posts: 21
Joined: 8/13/2006
From: Atlantic, IA, USA
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For motors start here
http://countdownhobbies.com/store/index.php?cPath=50&osCsid=ef48c3c989cec0e2187c44d5dd2981bb
and here:
http://www.giantleaprocketry.com/hpdefault.asp
And here to:
http://www.apogeerockets.com/rocket_motors.asp

The Gold Medalist motor make great air start or boost glider motors (long bun times).
http://www.apogeerockets.com/composite_motors.asp

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Post #: 39

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