3x Orbital Transport upscale

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James Duffy

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Thought some here might like to see this project that I started some 19 years ago, yet never finished...

I always wanted an upscaled Orbital Transport model with a radio-controlled glider, and planned a 3x version some twenty years ago. The plans sat dormant for a while, and I eventually ordered the parts and began cutting and gluing parts from cheap 1/4"-thick ply, adding some of the smaller details using basswood. For whatever reason the project was never finished, and the incomplete rocket idled in the rafters of the garage for years. Eventually it was moved to my warehouse for long term storage, and pretty much forgotten...until last week.

I dragged the unfinished rocket home, and assessed the degree of hangar rash that had been inflicted on the bird. The airframe and ply parts were in pretty good shape, but the basswood bits had to go. These were snapped off of the model, and the old parts were used to make new components from 1/4"- and 3/16"-thick balsa. With the detail parts out of the way the ply bits were given a good sanding, inspection, and de-funking. Nineteen years can add a lot of filth to a model, y'know...

Here's the wing section of the OT with the old basswood stuff ripped off.

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Most of the shortcomings with the model can be overcome, except one: the wings of the OT have taken on some pretty dramatic warps. There's not a thing I can do about that, so we're just not going to worry about it.

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The new balsa nacelle components are assembled, and all of the new parts are given a coat of diluted Elmer's wood filler.

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More later,
James
 
How'd your OT turn out James? I'm in the process of dim'ing out the original so I can build a 1.5 scale around 34.5 inches. Do you happen to know the dimensions length wise of the orbiter tube and the launcher tube in the original? I'm going to go with a BT-60 size low power tube. Hopefully a D12-3 will push it well enough.
 
How'd your OT turn out James?

Well, we'll all know in a few weeks. Keep watching this thread for updates.

I'm in the process of dim'ing out the original so I can build a 1.5 scale around 34.5 inches. Do you happen to know the dimensions length wise of the orbiter tube and the launcher tube in the original? I'm going to go with a BT-60 size low power tube. Hopefully a D12-3 will push it well enough.

The booster body tube on the original OT was 18" long, while the glider tube was 6.5" long. A D12 should be plenty for that size model, assuming you don't go nuts with overbuilding.

James
 
A few strips of wood and some appropriate clamps and a bit of time should straighten out your wings.
 
A few strips of wood and some appropriate clamps and a bit of time should straighten out your wings.

That thought occurred to me, as well. Would you add any moisture or heat to the process?

Keep in mind that these parts have probably been warped for at least a decade and a half. My initial impression is to just let it go, finish up with the warped parts, and redo the whole model if I like the results from the crusty, old version.

James
 
How'd your OT turn out James? I'm in the process of dim'ing out the original so I can build a 1.5 scale around 34.5 inches. Do you happen to know the dimensions length wise of the orbiter tube and the launcher tube in the original? I'm going to go with a BT-60 size low power tube. Hopefully a D12-3 will push it well enough.

Tone Deaf,
Here's a handy reference for the body tube sizes and lengths in Estes kits, thanks to the efforts of Mr. John Brohm. Thanks John.

https://rocketshoppe.com/info/Estes_Body_Tube_List_3.1.pdf
 
A clothes iron set at "cotton" heat with a bit of pressure applied can straighten those wraps and do so permanently. I did this with some Exocet forward fins that were made out of 1/4" ply. Takes a while and you'll need to do the counter warp twisting with your hands (oven gloves help) but it will work.
 
ToneDeafJr,
You can take the guide for the fin patterns that is near-to-the-last page of the plans to a local big copying center and pay them to enlarge the fin patterns by a factor of 1.5. You will then have patterns to trace all your fins.
 
ToneDeafJr,
You can take the guide for the fin patterns that is near-to-the-last page of the plans to a local big copying center and pay them to enlarge the fin patterns by a factor of 1.5. You will then have patterns to trace all your fins.

+1 to this method of enlargements, you will have to know the percentage you need the drawing enlarged too. Sometimes I use Inkscape to scale my drawings then save as a PDF and take to my local business copy center and have them print it, did that last summer for my Nike Hercules project, its so much easier to take measurements directly off the drawing at 1:1 than dealing with a scale factor for each measurement.
 
Sounds like a good idea Rich and Aerostadt. I'm working on a Vega right now and you are correct, sometimes it's just easier to take 1:1 measurements rather than doing the maf. Seems like my Vega is going to turn out to be a 1:46.7 scale
Maf for Vega.jpg
 
A decision has been made with regard to the warped wings: nope, not going to try and fix them.

Life is too short to try and repair two-decade-old things that weren't originally created in Italy and go "vroom." So, we're simply going to press on and complete the model as-is. First, the new replacements for all of the discarded basswood bits are sanded down.

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Next, diluted Elmer's Wood Filler is brushed onto the plywood wing components. After this dries for a couple of hours we'll drag it outside and sand it all down.

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I reached out to Frank Burke of Dynasoar Rocketry to inquire about having him cut a custom downsize kit of his existing Orbital Transport rocket glider. Less than 24 hours later the parts are already on the way. Frank rocks.

https://dynasoarrocketry.com/?page_id=740

I've already started researching the parts prices to do a fiberglass 7.5x upscale of the OT. Somebody stop me, m'kay?
 
James, sounds like a plan. Sometimes, it is time to move on. From the top your OT looks fine. I have Frank's regular OT orbiter rocket glider, but I have not flown it, yet. I have not thought about using it as a parasite glider. I will be interested to see how your glider works. I did fly a half shell orbiter with 1/8" balsa wings reinforced with 20 pound stationery paper and white glue twice last summer on my 4x OT and it held up fine. There was a fellow named Bob Brown in Colorado who contacted me by PM on TRF back in January 2011. He said that he was building an 8x OT, but I never heard any more news. The size of the whole vehicle becomes huge when you calculate the dimensions.
 
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He said that he was building an 8x OT, but I never heard any more news. The size of the whole vehicle becomes huge when you calculate the dimensions.

No kidding! I did the math on a potential upscale of the OT using the Madcow 7.5" tubing, which has an OD of 7.708". Dividing that figure by the original Orbital Transport OD of .976" yields an upscale factor of 7.897x, or, in simplified terms, 7.9x. As the original OT has an overall length of 23", that makes the upscale project over 15 feet in length! That's a big, big rocket.

Just for grins I drew the parts in Illustrator to cut the 7.9x parts from 6mm-thick G10 sheet using a water jet rig. Maximizing the efficiency of the parts layout to use the least amount of G10 sheet, the project will require two 3' x 4' sheets of material, plus an additional 1' x 2' sheet

Coming back to sanity: my vintage 3x version has been primed and sanded, which took care of a bunch of the hangar rash hickeys inflicted on the parts over the past two decades. Despite the ravages of time the parts still cleaned up pretty well, although this will always be a "stand ten feet back and squint" kind of rocket.

IMG_3071.jpg

The custom parts pack that Frank Burke prepared for the BT-70-based RC orbiter arrived today, less than 72 hours after our first email on the subject. That is the single greatest customer service accomplishment I have ever experienced in my life. Recall that this was a custom commission, not an off-the-shelf design!

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Paint is next,
James
 
Had an opportunity today to attach the detail parts to the Orbital Transport, and thought I'd share a photo.

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Note that I pre-painted both the interior surfaces of the assembled nacelle parts, as well as the bottom surface of the wings. This will eliminate the challenges of trying to get paint onto surfaces that will soon be inaccessible. Next step will be to apply fillets to the just-installed detail parts.

More later,
James
 
Looks good! My oldest brother built the kit back in the early 70's, but I do not recall it ever being flown. I have one of the re-issue kits in the pile, and hope to one day do an upscale, but with a free flight glider.
 
Hello James. ToneDeaf again. Do you happen to have patterns for the fins upscaled to BT-70 core?

I have the patterns for a 7.9X version, but it should be fairly simple to resize them for a BT-70 model. Give me a few days and I'll post the PDF here.

James
 
The next step really isn't high power in nature, but it will be a critical step in the completion of this project. The parasite glider we'll be using isn't a direct upscale from the old Estes Orbital Transport kit, but rather an 85% downscale of the Orbital Shuttle RC rocket glider kit offered by Dynasoar Rocketry. Frank Burke of Dynasoar was kind enough to custom-cut a short kit of parts for the glider.

First, we'll mark and cut the slots for the wing and vertical stabilizer on the glider. (Frank's website offers very comprehensive video instructions for each of his models, which I highly recommend!)

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With the wings mounted in place, we next mask the wings so that a thin, light coat of paint can be applied to the airframe tube. The wings won't be painted to both reduce gliding mass, and avoid the possibility that solvents in the paint might attack the foam.

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A set of cut vinyl markings have been sourced from Mark Hayes at Stickershock23.

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The markings for the glider are put in place. The 20+ year old nose cone needs to be refinished, as it is likely old enough to drink legally. The windscreen markings can be installed after that task is complete.

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After the radio gear is installed the glider will be complete. The entire glider assembly and finishing process has taken less that two hours total, which stands as an enthusiastic endorsement the products offered by both Frank and Mark!

More later,
James
 
Now that all of the detail parts have been installed the first coat of paint has been applied to the airframe. An cheap microphone stand is great for holding large rockets such as this.

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More later,
James
 

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Thanks for posting the pictures James. This has been exciting watching the build. What are you going to fly her on?
And, one more quick question. I've put multiple coats of spray paint on the Vega I'm building and I've started to get drips/runs every time I put a coat of paint on. I'm also starting to see some crackling in the paint. I wait overnight to sand but I still continue to get the the same result. I live in Charleston SC so it's not real cold here right now. Do you happen to know what's going on with the paint? Thank you in advance.
 
Thanks for posting the pictures James. This has been exciting watching the build. What are you going to fly her on?
And, one more quick question. I've put multiple coats of spray paint on the Vega I'm building and I've started to get drips/runs every time I put a coat of paint on. I'm also starting to see some crackling in the paint. I wait overnight to sand but I still continue to get the the same result. I live in Charleston SC so it's not real cold here right now. Do you happen to know what's going on with the paint? Thank you in advance.

I'll try to help. Let's make an assumption first that you are using gloss enamel spray paint. (If not, let us know.)

First: is the model primed? A quality paint job starts with a good coat of primer. I use Rustoleum Grey sandable auto primer for large models. Others have used other products successfully. The important thing is to use the same brand of primer as the brand of paint that you plan to use. Paints offered as "no need to prime" or "primer included" are trash, and shouldn't be used.

If the paint is dripping and running, it is being applied in coats that are too thick. Apply the paint in multiple light coats, fogging the early coats on. Don't worry about covering thin spots early in the process, as later coats will take care of that. A quality paint job on any size model will require anywhere from 4-10 coats, depending on brand and color.

The next part is really important, and may be causing the crackling that you are experiencing: once a coat is on the model, the next coat must go on in about 8-10 minutes! This allows for a factor known as "cross linking," where the lower coat is still tacky enough for the new coat to chemically bond to it. This is especially important for gloss paints.

If you are forced to pause in the process before you achieve an adequate finish, allow the paint to cure fully, perhaps 3-4 days. Sand the surface of the model with 600 grit sandpaper, and apply additional light coats, again about 8-10 minutes apart. Also, note that humidity can have a significant impact on cure time, and Charleston is notoriously humid for much of the year. Overnight is not long enough for consumer-grade spray paint to cure, especially in humid areas.

One last thing: for small models, use Tamiya spray lacquer primer and paint. It's expensive, but the results are fantastic.

Hope this helps,
James
 
Painting of the booster was finished up over the weekend, which allowed for the installation of the vinyl markings this morning.

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I've been very impressed with the quality of the markings supplied by Mark Hayes with Stickershock!

Next up:

* Install rail buttons
* Install shock cord and parachute
* Install motor retainer
* Cut, paint, and install simulated ram jet engines
* Sand and refinish glider nose cone
* Finish glider radio installation: servos are already in place, but I do not trust the cheapie $4 Orange-brand Spektrum knock-off receiver. I will be buying and installing a genuine Spektrum product.
* Balance glider
* Figure out some sort of glider mounting method. This may be as simple as an upscale of the kit design using a simple hook and a section of launch lug, but I'd really like to find some sort of more elegant solution. Ideally this would use a rail button on the underside of the glider nose that would engage with a mount on the booster.

Motor selection also needs to be assessed. The booster has a 38mm mount, and I'm leaning toward a 2-grain CTI case using a low- to mid-thrust reload. We don't want to damage the glider during boost and I'd like to limit overall altitude to ~500'. Any suggestions? Current mass of the booster with parachute, motor, and glider will be about 4 lbs.

More later,
James
 
My 4x OT came in quite a bit heavier at about 10 pounds. It flies on a full I or a low J and reaches about 800 feet. The glider appears very small at that altitude. On the very first flight the parachute was not blown all the way out of the body tube. Thereafter, I went with a piston, but extra weight in the nose cone (or near it) to pull out the chute might work, too.
 
If you want gentle an h97 is pretty good for that weight, I use it for my Titan dynasoar to about 400' but that's much more draggy and 85 ounces rtf.
 
Although I no longer have the rocket ,(it didn't survive a move) years ago I built a upscale orbital transport using Loc 2.6" tubing and an Aerotech nosecone. The glider was made out of either a Quest blunt nose cone or a Big Bertha nose cone a tubing. It had a 29mm motor mount in the booster. I also used some of the ram jet parts that came with the SR-71 on the bottom of the boxed in engine area under the wings. Looked pretty cool and flew great.
 
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