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4X upscale Orbital Transport

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JoeG

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First, I realize this has been done before and I have copied some of the techniques I have read about for the glider portion of this rocket.

I have upscaled a lot of my favorite kits that I had when I was younger. The Pathfinder was my first and the Trident and Mars Lander have been among the others.

This was designed and constructed some time ago and I have constantly come up with excuses not to fly it. Too windy, field too rough, too much prep, or just plain chicken. Finally ended up flying it last Saturday because I forgot how much work went into it in the first place. The temps were in the 70's and wind was pretty much non existent.

The boost was on an AT I211 and the rocket went to just over 500 ft. I would like to get to 750 feet or so. High enough for the glider to see a little more action but not so high as to make visibility difficult for these tired old eyes. The glider is radio controlled with elevons to control pitch and roll. It flew better than expected.

Thanks to my son Adam, for the photos and video link. The video is titled 3x Orbital Transport because it has been so long since it was built I forgot what scale was used. The original used a BT50 for the booster and I used a 3.9" Loc tube so the scale is approximately 4 to 1.

The boost was very straight and the glide was fast but very controllable. I was concerned that the glider weighed too much to fly well but was able to control the descent easily and was even able to get it in a nose up attitude for a second. The flip on landing was due to the tall grass and the speed of the glider and coming close to the access road just behind us. We learned a lot and the next flight will be better.

4x orbital transport 2.jpg4x orbital transport 3.jpg4x orbital transport.jpg4x orbital transport4.jpg

[video=youtube;C_al0H7im3c]https://www.youtube.com/watch?v=C_al0H7im3c[/video]
 

burkefj

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Congrats on a nice flight, looks great.

Frank
 

aerostadt

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Congratulations! I have launched my 4x OT a total of 14 times. Sometimes repairs have been substantial, but successful. My early flights used a reloadable Aerotech I284. For my later flights I have used CTI J285 or J270 to cut down on prep time. I always have to be careful to drill the delay charge down to a good delay time. My Flight #13 recorded an apogee of 795' using the CTI J270 and about a 6 sec. time delay. My total flight weight is around 12 pounds. My earlier orbiters weighed on the order of 2.5 pounds, which was too heavy for a good glide. My last 2 flights used a half-shell body tube glider and weighed about 1 pound 3 oz. The glide was long and I had plenty of time to practice R/C control.
 
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JoeG

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Thanks Frank.

aerostadt, I "borrowed" a lot of info from your posts. My glider weighs 2 lb. 6 oz. and I thought it would just fall out of the sky.

I'm using electronics (RRC3) for separation so I don't have to deal with delay times. My all up weight is close to yours as well. The J285 and the J270 look like what I am looking for as far as total, average, and maximum thrust as well. Enough boost to get it off the pad smartly without leaving those big fins/wings behind and still having enough total impulse to get some more altitude. The AT J275 might be an option for me since I do not have a local CTI dealer.
 

pondman

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Excellent Joe! Pretty neat to see you combine both of your hobbies. Hopefully you can fly it at our field if we ever get a perfectly calm day.
 

JoeG

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Excellent Joe! Pretty neat to see you combine both of your hobbies. Hopefully you can fly it at our field if we ever get a perfectly calm day.
That's the plan. Need more power!! :)
 

ECayemberg

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Awesome Joe! Cool flight!

Hope to see it at Midwest Power!!!
 

burkefj

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I'm pretty sure using appropriate design/materials we could get your glider strong enough and under a pound. It doesn't have that broad a wingspan. If you aren't hung up on having dihedral it can be stronger and still use elevons for control without issue. The dihedral was really just needed since it was a free flight design. I will say that having a glider that size go much above 750 feet, it gets really small and hard to determine orientation, at least for me. If you get the glider lighter, you don't really need to go that high, and still get a minute or more of glide time, which is plenty for a public launch where you don't want to hold up the flite light for a long duration glider flight.

Frank
 
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aerostadt

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Joe, I've been thinking also about the Aerotech J270 DMS. Our club vendor no longer sells CTI, so I ordered those motors from Wildman. Our club vendor does sell the AT J270 DMS, so I think that I will go with those next. (I think Apogee also sells the AT J270.) At Frank's urging I did make another white Orbiter glider (with the dihedral and 2.6" diameter) lighter. It is described on another TRF thread. I just weighed the white glider with electronics (1s Lipo) and it comes in at 1 lb 2 oz, but I have not flown it, yet, so I don't know for sure if it will hold up. My red glider holds up to the aerodynamic loads fine. You might consider another glider build for a winter project. The nice thing about the 4x OT, once it is built, is that you can fairly easily build new gliders. I am tempted now to go back and ask Frank about in-flight ignition.
 

burkefj

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So for airstarts you will add weight, the loaded motor in back would be approx 53 grams if you went with an e-6, you would need a small separate 3s lipo and e switch to fire the igniter, and you'll have to re-balance things so that you are stable with a loaded motor in back for initial glide, then will be nose heavy on burnout and have to pre-program in some up trim. You'll add maybe 3-3.5 ounces to the model most likely.
 

JoeG

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I'm pretty sure using appropriate design/materials we could get your glider strong enough and under a pound. It doesn't have that broad a wingspan. If you aren't hung up on having dihedral it can be stronger and still use elevons for control without issue. The dihedral was really just needed since it was a free flight design. I will say that having a glider that size go much above 750 feet, it gets really small and hard to determine orientation, at least for me. If you get the glider lighter, you don't really need to go that high, and still get a minute or more of glide time, which is plenty for a public launch where you don't want to hold up the flite light for a long duration glider flight.

Frank
The glider is pretty strong now. The wing is plywood. That's why it's so heavy. ;) I hate to change the design or shape or lose the dihedral. That's the whole purpose of the up"scale" for me. Just like the small one only bigger. I do get it that more glide time, up to a point, would be a bonus though.

I agree that 750' would be about my sight limit. I had no trouble getting oriented on Saturday but it was not very large at 500'. I'm using all heavy duty tubes and nose cone. I'm sure I can save some weight. Not looking for long glide times but having enough time to set up for a decent landing would be nice. :)

Thanks.
 

JoeG

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Joe, I've been thinking also about the Aerotech J270 DMS. Our club vendor no longer sells CTI, so I ordered those motors from Wildman. Our club vendor does sell the AT J270 DMS, so I think that I will go with those next. (I think Apogee also sells the AT J270.) At Frank's urging I did make another white Orbiter glider (with the dihedral and 2.6" diameter) lighter. It is described on another TRF thread. I just weighed the white glider with electronics (1s Lipo) and it comes in at 1 lb 2 oz, but I have not flown it, yet, so I don't know for sure if it will hold up. My red glider holds up to the aerodynamic loads fine. You might consider another glider build for a winter project. The nice thing about the 4x OT, once it is built, is that you can fairly easily build new gliders. I am tempted now to go back and ask Frank about in-flight ignition.
I think that looks like a likely candidate too. I can get them from Merlin Missiles on site or will be at MWP so could stock up from Tim.

I am planning to build another glider this winter. I have some slight damage to repair on the booster. The two engine nacelles on the left "wing" hit a big round hay bale on landing and got shoved forward breaking off the lower strake that runs between them. I didn't know how all that fin/wing area would handle a rough recovery but it seems to be fine.

I too was wondering about airstarts and you will notice I left a 32mm hole in the back just in case. Ignition shouldn't be that difficult.

Thanks for the comments. This definitely was the attention getting flight of the day.
 

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