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Upscale Orbital Transport Design Info Request

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NorthwoodsRockets

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I am a newbie BAR looking for information on the major pitfalls of up-scale rocket design in general and specifically up-scale Orbital Transport projects. Got my NAR level 1 & 2 this summer and have a new project in mind. My goal is to build a 3X (54 mm motor mount) and 5.44X (98 mm motor mount) versions of the Orbital Transport and (I am reluctant to admit publicly:eek:) ultimately to fly an M powered :y: OT. I understand the ultimate goal may be way beyond my capability. I have found evidence on the web of various up-scale versions by Caesar ?, Dave Grumbine, Hawk’s Hobby, Joe Michel, Bob Morstadt, Steve Pollak, LeeR, Kevin Trueblood and last but certainly not least Jason Ware. Jason’s 4X version, Steve Pollack’s J330 powered and Kevin Trueblood’s OT project are truly impressive. (I hope I am not out of line using names.:confused:) Any information on any of these builds or on up-scale dangers in general would be greatly appreciated. Thanks for your help.
 

MarkII

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First of all, welcome back to the fastest flying hobby, and welcome to The Rocketry Forum.

I don't know about any issues specific to upscaling the OT, but in general, the the main issue with upscaling any design is.......

.........you need to use bigger motors.

Also, because you will be using different materials and a larger motor, you will need to find the balance point of your upscale and determine if it will be stable. The Center of Pressure of the upscale should be pretty much in the same place as it was in the original (but scaled up, of course), and you will need to determine of the balance point (Center of Gravity) of the design (when it is full loaded for launch, with a live motor, your recovery system and protective wadding packed in) is a suitable distance ahead of the CP. The standard rule of thumb is to make sure that the CG is ahead of the CP by at least the same distance as the diameter of the rocket (this is referred to as "one caliber of stability"). If the CG is closer to the CP than this, your rocket is in danger of doing loops and chasing its tail when it leaves the launch pad. To remedy this situation, you will need to look at your design to see if there is any place where you can remove weight from the rear or else you will need to add weight to the nose.

If you are particularly thorough (like me), you will upscale the original design's launch lug, too. (You don't HAVE to, but I like to do it.) But I don't get crazy about making the thickness of the fins an exact upscale, though. Obviously, upscaling a low-power design to something that will fly on high power motors may require taking some steps to enhance the strength of certain parts (like tubes on pods, for example), and because of the larger mass of the upscale, you may need to switch to a different type of recovery system (or a different method of deploying it). Streamers will not slow down the descent of a large rocket to a safe speed, for instance. I don't worry about getting the thickness of the fins to be an exact upscale of the fin material of the original design. It can be hard to find suitable material that is in scale, and it can also result in very heavy fins. I try to get close, within reason, while being mindful of the weight.

Beyond a certain point, upscaling the Orbital Transport will probably call for adding RC guidance to the glider.

Did you build the Orbital Transport during your previous stint in model rocketry? If you didn't, or even if you did but it was awhile ago, you might want to consider building an original-size OT just to familiarize yourself with the design. If you do, then you are in luck; Semroc Astronautics has a reproduction of this long OOP (out of production) kit. You can find out more about it here.

If you can give us more details about your planned upscale (scale? what motors will you use?, etc.), then me and other people on this forum can give you more detailed and more specific advice.

MarkII
 
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NorthwoodsRockets

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I built the original OT in the early ‘70s. It probably got tossed when my mom moved a couple years later. So, I am currently building the Semroc version. I have used RockSim quite a bit over the last year and just upgraded to RockSim 9 because of the scale feature. Just tell it to scale 3 times and - presto - you have measurements.
My current plan consists of LOC Precision paper tubes – 3” BT for the booster, e-bay for dual deployment, 2.14 BT glider body, 2.14 motor mount, 1.52 BT for the scram jets. I was also going to extend the motor mount tube with a 1.14 MM tube up to the canards for an internal “spine”. Probably all fins TTW (that’s a lot a fins.) I was going to use ¼” birch plywood for the booster fins glassed to the “spine.” And after seeing Steve Pollack’s cato, I would probably glass the outside tube also. The glider gets 3/16 birch plywood fin/wings. A friend is working on a vector drawing of the fins so they can be cut on a programmable router table. I haven’t decided if I want to turn a balsa nose for the glider or cut one out of foam. (Unless you know where to get the right style in 2.14”.) I wasn’t thinking of radio control for the glider in the first build.
I don’t know much about high power motors, but picking the lowest impulse I can find in RockSim, an I117FJ takes it to 1,500 ft. (Probably considerably less with all the glass.) 3,700 ft on an I65W. 3,200 ft on a Cesaroni J280SS.
I’m not thinking much about the 5.44X version until I get some experience with the 3X version. Although I thought about the Giant Leap’s composite fins.
 

MarkII

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Wait a sec... you want to fly a boost glider on a J? And eject the 26" long, 15" wingspan glider at 3,000 - 3,700 feet? And have it glide back down WITHOUT any kind of radio control?

You are going to use DD for the booster recovery, but you are just going to let the glider go off on its own, with no control, up at 3k and let the wind take it where it will? Do you have experience with deploying free-flight gliders at 2-3,000 feet? And with tracking a small floating object for 30-50 miles?

But wait -- with 3/16" birch plywood wings, I'm wondering if the glider will even glide. How heavy will it be?

If you are concerned enough about the stress that the booster will undergo that you want to glass it, what about the glider?

It sounds like you want to build the booster to be able to withstand a cato. Do you consider that catastrophic event to be likely?

Before you do anything else, do a reality check. Get some BT-70 and some 3/16" plywood and build a prototype of the glider, and then see how well it glides with hand-tosses.

What you have outlined is one very serious project. How much rocket building and launching have you done in the short time since you became a BAR?

If I was to design a 3x Orbital Transport, I would use something like T300 from Balsa Machining Service for the booster's airframe and standard thin-walled BT-70 for the glider's airframe. I would use 1/4" basswood or paper-reinforced balsa for the booster fins and lightweight 3/16" balsa for the glider wings. (Actually, for the booster fins, etc., I would consider using sheeted foam core.) I would go with TTW fin construction for the booster and surface mount the fins on the glider. I would use a Semroc BNC-70D nose cone in the glider (maybe rounding the tip a little to make it more elliptical, and possibly hollowing a little of it out to make it lighter in weight) and contract with Roachworks Custom Turnings to turn a 13.2" long 3xBNC-50Y for me for the booster nose cone (because I have never tried to turn a nose cone that big). I would NOT cover the booster airframe with fiberglass, because it wouldn't need it. I would aim for a target weight that would allow me to launch my upscaled OT on a long-thrusting G, an F40 or a small H. I would glide-trim the glider so that it transitioned into nice, tight circles or else I would outfit it with RC, and I would put some type of tracking device in it. I would aim for a deployment altitude of around 1,000 ft. (if I was ambitious) and I would launch it in a huge range. If I had the glider return via free flight, I would recruit a small army of volunteers in ATV's to help me track and recover it.

But that's just me.

MarkII
 
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MarkII

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Also, if you have not flown large-scale boost gliders before, I would think about picking up one the Thunder series of Edmonds gliders, such as the Dee Cee Thunder, and using it to gain some experience before tackling the 300% scale Orbital Transport project.

MarkII
 

rrobe99999

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Great advice given here. Orbital Transport is my favorite rocket. Check out my 3X OT that won the best rocket contest last month over in the contest forum. I used Joe Michel's build thread as a guidline for my project. I always build and fly the original rocket before I build the upscale. Then I just make sure the CG is in the same place on the upscale.

You are right on with the BT sizes for your 3X upscale. I used an incorrect balsa BT70 cone for the glider. I don't want to make my own NC and it was close enough. The glider wings and stab are made from 1/8" balsa. I put on a light coat of paint and 1 oz weight in the NC for a final weight of 7.6 oz. My glider is very well trimmed and glides very far away. I considered flying a tracker in the glider but did not want to risk loosing a $100 tracker in a $20 glider. Fortunately we have a big field, but I do plan to build an RC glider for it one day. I want to build an Edmuds Arcie 1st to get some RC experience.

My booster is built with 1/8 plywood wings, tips and rudders. I did tip to tip fiberglass over the wings and motor mount. Fiberglassing may not be necessary, but I'm glad I did it, because my 1st flight crashed. I just had to add some new BT, and she was good to go. The rest of the booster surfaces are 1/8" balsa. 1/8" basswood would have been better. I tired to keep the build light. Booster weight is 3.6lbs W/O motor or chute. I have flown twice on H180s using motor deploy to about 800' or 1000'. I don't want to go any higher, or I would loose the glider. Even with RC on the glider, you would never need a 54mm motor. Go with a 38mm or a 29mm.

Please post pics of your project. I look forward to seeing the M version.

Russ Roberts
SEARS572
TRA L2
 
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MaxQ

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I am a newbie BAR looking for information on the major pitfalls of up-scale rocket design in general and specifically up-scale Orbital Transport projects. Got my NAR level 1 & 2 this summer and have a new project in mind. My goal is to build a 3X (54 mm motor mount) and 5.44X (98 mm motor mount) versions of the Orbital Transport and (I am reluctant to admit publicly:eek:) ultimately to fly an M powered :y: OT. I understand the ultimate goal may be way beyond my capability. I have found evidence on the web of various up-scale versions by Caesar ?, Dave Grumbine, Hawk’s Hobby, Joe Michel, Bob Morstadt, Steve Pollak, LeeR, Kevin Trueblood and last but certainly not least Jason Ware. Jason’s 4X version, Steve Pollack’s J330 powered and Kevin Trueblood’s OT project are truly impressive. (I hope I am not out of line using names.:confused:) Any information on any of these builds or on up-scale dangers in general would be greatly appreciated. Thanks for your help.
Definitely one of the cooler upscales one could do....

 

rrobe99999

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Wow, is that yours MAXQ? It looks like a 5.5X. I don't see any RC linkage on the glider. Do you have any more info? BTW this thread might be more appropriate in the glider forum.
 

NorthwoodsRockets

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MaxQ,
"That's what I'm talking about." :clap: What a beautiful build. Truly inspirational. I'd love all the info I can get. Thanks
 

MaxQ

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Wow, is that yours MAXQ? It looks like a 5.5X. I don't see any RC linkage on the glider. Do you have any more info? BTW this thread might be more appropriate in the glider forum.
Nope ...wish it was.
I love that design...and this size.

I believe that is Mr. Pollak's built upscale.

I do have a Wasatch SST that I fly (M. Canepa's pic here) ....back engineered it from a built kit I borrowed. I'm converting it to RC from FF ...hope to have something ready by Nov 1.

SST.jpg
 
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MaxQ

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MaxQ,
"That's what I'm talking about." :clap: What a beautiful build. Truly inspirational. I'd love all the info I can get. Thanks
Think you've researched it pretty good...

Two of my favorite Estes kits...the Orbital Transport and the Little Joe II.
I have upscales of both...the OT I fly is the Hawks Hobby upscale.
Nice kit.
http://api.ning.com/files/-TpuJfuq7ypOTb*kN1ZPwuYqrUVCvBrirJ14acvW0vM=/SuperOrbitalTransport.jpg


The LJ - II of course I made big enough for my liking and budget....
 

NorthwoodsRockets

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MaxQ,
I'd love to get any specs off the Hawk's Hobby Up-Scale like: Scale, tube type, fin material and thickness (TTW?), recommended motors, any special construction technique(s) and anything else you think might help me like what you would change if you built it again.
Thanks
P.S. Nice OT (I missed the link at first.)
 
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MaxQ

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MaxQ,
I'd love to get any specs off the Hawk's Hobby Up-Scale like: Scale, tube type, fin material and thickness (TTW?), recommended motors, any special construction technique(s) and anything else you think might help me like what you would change if you built it again.
Thanks
P.S. Nice OT (I missed the link at first.)
It is a bit bigger than the Semroc kit...still in the low to mid power range...
Hawks Hobby website appears to be under construction...
This is from Perfoprmance Hobbies:


Super Orbital Transport

Booster Glider
1.640 in. Body Diameter 1.325 in.
40.5 in. Length 15 in.
13.5 in. Fin Span 8.75 in.
5.6 oz. Weight 2.6 oz.
Stages: 1
Recovery: 24 inch Rip-stop parachute
Engines: D12-3, E9-4, E18-4
Kit Contents:
7 body tubes - assorted sizes
2 nose cone
1 coupler
1 set of balsa fins (7 sheets)
1 engine mounts
1 set of 3 centering rings
1 parts pack
1 parachute - assembled
Decals & Instructions

http://blastzone.com/performancehobbies/store.asp?groupid=52720089332124
 
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sylvie369

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Hold on - that kit he's carrying can't be the same one that flies on E9-4 motors, right? That looks like either a 38mm or a 54mm in the back end, and it's got to be 4" or so in diameter.
 

NorthwoodsRockets

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I believe the picture is of Steve Pollack walking with a 5-6 times up-scale OT. MaxQ was talking about the Hawk's Hobby (Approx. 1.6 X) up-scale Kit of the Orbital Transport. Unfortunately, Hawks Hobby took a beating by Ike (?) and subsequent issues and is down for a bit, but hopefully recovering.
 

jadebox

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jadebox

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Whew boy...that other CATO o the pad must've hurt.
That's one reason I decided to gather all those photos in one place. I was amazed to see that rocket return to flight after that.

-- Roger
 

NorthwoodsRockets

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I have made some progress on my 300% OT build.
I built and flew the Semroc model a few times.
I assembled the parts for the up-scale [booster nose cone, BT-, MMT- (including 29 and 38 mm adapters), and e-bay-tubes and centering rings from LOC Precision. I can’t begin to thank Barry Lynch enough for the incredible service. I ordered 1/8”, 3/16”, and ¼”Plywood from SIG mfg. They are great too. Finally, I got one 3”x3”x12” balsa block from AC Supply for the glider nose cone.]
I built most of the glider. Turning the balsa nose cone on a ½” dowel stuck into a drill press was one of most rewarding things I’ve done in my short rocket career. As predicted, the 3/16 plywood winged “glider” glides slightly better than a car. (More on that later.)
I’ve cut most of the fins from ¼” plywood, glued the main wings to the MMT “spine” as I think of it, and glassed the assembly tip-to-tip. I cut the Body tubes to length and fitted the aft BT to the wing/spine unit.
I would love some guidance on placing the dual-deployment e-bay. I purchased an extra long e-bay so that I could glue the canards to it for extra strength. However, I don’t think there is enough room for main shoot between the e-bay and the glider mount where the “spine” ends.
I just ordered (from sollercomposites.com) a fiber glass sock to strengthen all body tubes. I plan to vacuum bag them. I also ordered 1 yd 3K carbon fiber to make sandwiched glider wings with plywood edges and foam core centers for a second glider attempt.
I'd specifically love to hear from anyone with up-scale OT experience.
Here are some photos.

OTSections.jpg


OT_OnePiece.jpg
 

aerostadt

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I posted a review of my 4x Orbital Transport on EMRR last month. You can find it there for the date 10-21 (2009). I follow Jason Wares and use an I284. The altitude is about 1,000 ft. The first flight I lost the booster, but I rebuilt it. On the second flight the orbiter was torn off on the way up. I hoping to put everything together to work the next time.

Bob
 

The EGE

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Before you even consider flying the giant OT, get a Deltie Thunder for 25 bucks, and launch it several times, first on D12-3s, then E9s or E11s, then finally an F12-5J.

The Deltie Thunder has a darned good glide ratio - prolly better than 10:1 if you trim it right. I've had one sucessful flight on it that ejected no more than 200 feet up on a D12, and it was 20 feet up when it settled into the trees 600 feet away. You're talking a glider roughly this size, ejecting at over 5 times the altitude. It could easily land a mile or more away.

And yes, the OT glider is a very good glider. I have a homemade clone that's not trimmed quite right, and it's glided over 1000 feet from a 300 ft ejection.

You're either going to need RC control, or a very good radio tracer combined with someone mobile with good binoculars. And at least 2 square miles of flat land.
 

mjennings

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Can't speak to doing the upscale but I've seen Steve Pollak's OT a number of times at Spaceport Rocketry Association's launches. It's downright awesome. He claims half the weight is epoxy from rebuilding it (it's quite a bit shorter than scale, now, if I remember correctly, and I'm pretty sure it was a rebuild after the cato and not a new build, also if I remember the stories right.), and proudly advertises it as the lowest J power flight of the day every time he launches it.

yeah all the pictures posted so far are Steve's OT minus the one by NorwoodsRockets in post #23
 
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NorthwoodsRockets

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I posted a review of my 4x Orbital Transport on EMRR last month. You can find it there for the date 10-21 (2009). I follow Jason Wares and use an I284. The altitude is about 1,000 ft. The first flight I lost the booster, but I rebuilt it. On the second flight the orbiter was torn off on the way up. I hoping to put everything together to work the next time.

Bob
Wow Bob, Thanks for telling me about the EMRR write-up. That was great information. Pictures of your OT inspired me back in August to go ahead with this build.

My 3x design called for 1/4" plywood on the booster. So, without knowing better, that's what I've started with. I can't wait to get back and weigh my glider. Again not knowing better it was built with 3/16" plywood. I don't think it is much more than 1.6 pounds at least before the (considerable) nose weight. It probably is much heavier because, as I say, it doesn't glide much. I am looking forward to building a new glider over vacation with carbon fiber over foam core.

It was also great to hear about your three point attachment. I thought that would be a good idea, especially with spin stabilization, which, based on my flights of my Semroc OT, is crucial.

I have even less experience with RC than rockets. My plan, when I finally got around to RC was to actuate a rudder on the tail fin rather than the elevons. That seems easier to do. Would it work?
 
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aerospike

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Shouldn't this thread be posted in another forum? I think "scale" refers to drawings, documents and build threads of scale models of existing real space and aerospace vehicles.
 

George Rachor

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Anyone know where I could get a repacement set of Hawk Hobbies Replacement Decals? Although I am willing to buy an entire set I really only need the glider cockpit windows.

George
 

MaxQ

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Anyone know where I could get a repacement set of Hawk Hobbies Replacement Decals? Although I am willing to buy an entire set I really only need the glider cockpit windows.

George
Hawks Hobbies might be back online and could provide them...they were going to send me a set.
Also....Sandman can provide them....
 
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