Source for Scale Space Shuttle ET and SRB Nose Cones?

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JRThro

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I am looking for either balsa or plastic nose cones for a space shuttle model that will have the external tank based on a BT-60 tube and the SRB's based on BT-20 tubes.

Does anyone know of a source for these nose cones?
 
I am looking for either balsa or plastic nose cones for a space shuttle model that will have the external tank based on a BT-60 tube and the SRB's based on BT-20 tubes.

Does anyone know of a source for these nose cones?

I can make them.
 
Really? ;)

What would you need from me?

I have scale drawings for the Shuttle based on SRB sizes from BT-20 through BT-60.

I'll send them to you and after you look them over we can decide from there.
 
I have the foam brick space shuttle and I'd like to make an ET and SRB's to stack with it. I'm unsure of the scale of the orbiter. Does anyone know what it is? Ted
 
I have the foam brick space shuttle and I'd like to make an ET and SRB's to stack with it. I'm unsure of the scale of the orbiter. Does anyone know what it is? Ted
I presume by foam orbiter, you mean the old North Pacific foam orbiter, now produced by Guillow’s. If you have something different, then let me know the name of the company, the wingspan, and the fuselage length from nose tip to end of wing trailing edge.

I do not have one handy to measure. IIRC the wingspan is oversized, so if you go by span it is something like 1/94 scale (give or take, this is from memory), and if you go by fuselage is it more than 1/100 scale.

Here is a drawing I did up that has the full size dimensions and also dimensions for 1/72:

https://homepage.mac.com/georgegassaway/GRP/Scale/Drawings-shuttle-G/FAI_Shuttle_1-1.GIF

At full size, the ET is 333” (not including the intertank region which bulges out to 337”). The SRB’s are 146”.

If you did a shuttle based on BT-60’s that would be 1/89 scale, with an ET Diameter of 3.74”.

For a shuttle based on BT-55’s, that would be 1/110 scale, and an ET of 3.02”.

I have done both. A 1/110 model with BT-55 SRB’s, using a scratchbuilt balsa orbiter.

I also did one using the North Pacific (Guillow’s) , as a test boilerplate. I think for that one I fudged the scale factor such that even though it used BT-60 SRB’s, the shuttle was scaled at around 1/94 to 1/96 scale.

NOTE - The image below was reduced when uploaded to TRF. To see the original 1/72 drawing, with more legible text, use this link:
https://homepage.mac.com/georgegassaway/GRP/Scale/Drawings-shuttle-G/FAI_Shuttle_1-1.GIF

- George Gassaway

FAI_Shuttle_1-1.jpg
 
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I've done some CAD drawing of the shuttle (not as elaborate as George's) scaling the shuttle for different size SRB's.

I have them in BT-5, BT-20, BT-50, BR-51, SERIES 11, BR 55, BT-56, BT-60 AND SERIES 18 SRB tubes. The tank never quite matches existing tubing but it comes close in a few.

BT-5's come close with a 29mm motor tube for the tank.

BT-20 has a BT-60 size tank (real close!)

BT-51 is close to using a BT-70 tank body.

Series 11 (from SEMROC) is almost a perfect match to a BT-80

And a BT-56 is real close to being sized right for a 3.00 Big Daddy tube (BMS has that tube).

A BT-60 is close to using a series 36 tube (also SEMROC).

And the series 18 SEMROC tube as an SRB is a close match to a BT-101.

All close but each are off by 2 or 3 hudreds of an inch.
 
I am looking for either balsa or plastic nose cones for a space shuttle model that will have the external tank based on a BT-60 tube and the SRB's based on BT-20 tubes.

Does anyone know of a source for these nose cones?


Dr. Zooch's shuttle kit has exactly those cones, and the kit price is quite reasonable, and the quality is high.

The Doc has set me up with spare parts before, so I'm sure if you emailed him he'd send ya a quote for nosecones... :)

Whatcha got up yer sleeve?? OL JR :) :D
 
I presume by foam orbiter, you mean the old North Pacific foam orbiter, now produced by Guillow’s. If you have something different, then let me know the name of the company, the wingspan, and the fuselage length from nose tip to end of wing trailing edge.

I do not have one handy to measure. IIRC the wingspan is oversized, so if you go by span it is something like 1/94 scale (give or take, this is from memory), and if you go by fuselage is it more than 1/100 scale.

Here is a drawing I did up that has the full size dimensions and also dimensions for 1/72:

https://homepage.mac.com/georgegassaway/GRP/Scale/Drawings-shuttle-G/FAI_Shuttle_1-1.GIF

At full size, the ET is 333” (not including the intertank region which bulges out to 337”). The SRB’s are 146”.

If you did a shuttle based on BT-60’s that would be 1/89 scale, with an ET Diameter of 3.74”.

For a shuttle based on BT-55’s, that would be 1/110 scale, and an ET of 3.02”.

I have done both. A 1/110 model with BT-55 SRB’s, using a scratchbuilt balsa orbiter.

I also did one using the North Pacific (Guillow’s) , as a test boilerplate. I think for that one I fudged the scale factor such that even though it used BT-60 SRB’s, the shuttle was scaled at around 1/96 scale.

Actually several years later I did a 1/87 scale shuttle boilerplate (BT-60 SRB’s and 3.82” ET), but also used the same foam orbiter even though it was a little undersized.

NOTE - The image below was reduced when uploaded to TRF. To see the original 1/72 drawing, with more legible text, use this link:
https://homepage.mac.com/georgegassaway/GRP/Scale/Drawings-shuttle-G/FAI_Shuttle_1-1.GIF

- George Gassaway
Thanks for the response George. I'm talking about the Estes gliding orbiter. It was originally part of a starter set. It ejects the motor pod and the rather heavy glider is supposed to glide. I had poor results launching it alone(power dives into the ground) so I'd like to airstart it after burnout of the stack motor. I'm not looking to build an exact scale model just sport scale. I'm thinking that a D-12 mounted in the ET with C's in the SRB's would look cool if it can be made to work. Has anyone out there pulled it off? Ted
 
Thanks for the response George. I'm talking about the Estes gliding orbiter. It was originally part of a starter set. It ejects the motor pod and the rather heavy glider is supposed to glide. I had poor results launching it alone(power dives into the ground) so I'd like to airstart it after burnout of the stack motor. I'm not looking to build an exact scale model just sport scale. I'm thinking that a D-12 mounted in the ET with C's in the SRB's would look cool if it can be made to work. Has anyone out there pulled it off? Ted

A lot of builds have the motor in the ET..not sure how many had motors in the ET AND the SRBs....maybe that would work.

Motors in the scale locations.....

I think having a flying space shuttle model with motors in the "scale locations"
(in both the Orbiter and the two SRB's) must be like the Holy Grail of space modeling..
I hear it come up every so often.....a lot of people would like to do it.

Over the years, a couple of persons attempted it...and pulled it off.

In big scale...Andy Weorner of course (he managed to fly it under "active RC control", but then again...he has very experienced thumbs from years of RC flying and from what I heard in our conversation...he crashed some before he solved the weight problem and lightened the wing loading on the glide).

Rolf in Germany did a beautiful build with mixed results...(it pranged)

In LPR/MPR models...American Spacemodeling from December 1984 had a small article about Bill Dye's model that had five motors in the scale locations and minimal clear plastic fin area on the SRBs....it flew successfully according to the article...and he was working on a method to drop the SRBs...and have the orbiter glide recover.
Maybe he did...don't know....

I'm sure George can tell us plenty after his many builds...

Anyone else hear about someone doing it successfully?
 
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Where's the N1???

Funny you ask!! I was looking at it the other day! I am drawing it up in my tech. drawing class in Auto Cad. I wish I had the program here so I could work on it at both places. I would LOVE to fly it at TARC but I don't think I could convince Trip since its a 14 motor cluster :p

Ben
 
Could you do one for a ET - BT of about 7 " diameter?

Sure easy...but not cheap. I just need to know the exact size. Things get expensive when you go big.

But I think you know that.;)

What material? I'd think fiberglass/epoxy over foam.
 
I really do not recommend doing a clustered shuttle. The thrustlines and the thrust levels have to be balanced out properly. And they all have to ignite just right, or the wide spacing of the engines apart from each other will make the model veer off at liftoff.

For my own models that I tested out thru the years, I only did one that had a true cluster in the SRB’s for thrust, about 1/100 scale with BT-55 SRB’s. It used a North Pacific (now Guillow’s) foam orbiter, and to balance out the mass of the orbiter I shifted the noseweight inside the ET nose to the -Z axis (Orbiter is on the +Z axis), to balance it out. This allowed the SRB’s to have the engines in the center of the SRB’s. I used a D12 engine in each SRB. I wanted to see how a truly clustered shuttle with “main power” in the SRB’s would work out. I knew the risk. I figured if it worked well 10 times, I might go for it for a serious model. Well, on flight #1, both D12’s ignited. But they did not ignite exactly at the same time, so there was a thrust curve mismatch. Attached is a B&W photo showing it. Hard to tell in the pic, but one D12 had produced more thrust than the other D12, and caused the 3/16” launch rod to bend as the shuttle went up the rod. As it started to leave the rod, the bend un-did itself, which caused to shuttle model to do a strange “whip roll”, and then when it settled out it was climbing at a 45 degree angle. That was enough of a close call for me, as I said I was looking for it to work 10 times, and it came close to disaster on the first try.
Clustershuttle_1988.JPG

Years later I tried another approach. F engine in the bottom of the ET, but with “Token” A motors in the SRB’s. The SRB’s were rigged to be sepped, so the A3’s also were used for a time delay and ejection charge for the SRB’s. Well, flight #1, the F in the ET chuffed, so it did not take the model up for a couple of seconds. But, the A3’s fired too. Their thrust was enough to push the model up the rod a couple of feet. Then it fell back down and hit hard, breaking an SRB aft mount. So when the F in the ET did finally fully ignite and carried it into the air, one of the SRB’s was loose, only being pulled by the front end. Since the stability was based on a big fin on each SRB, that played hell with he stability, it went nuts.
I tried to fix the problem of that approach. Same model, but sitting on a switch mounted to the pad (a N.C. switch held "open" when pressed). When the F in the ET lit, and pushed the model up, the switch would close and fire current through extended leads going to flashbulb ignitors in the SRB A3’s. So, the launch sequence was ignition of the F, move up the rod an inch, then ignition of the A3’s. But, I never got both A3’s to ignite. Most of the time only one lit, and at least once, zero lit. So of course this also meant that the "dead" SRB’s free-fell to the ground since they counted on the A3 ejection charge to deploy a chute (The ultimate model I ended up building has no engines in the SRB’s . There is a wind-up timer that starts running when the SRB seps, then about 2 seconds later it triggers a rubber band driven system to push off the nose and deploy the chutes).

The only reason to even bother with the “Token” A3’s was for scoring flight points in a contest. I just decided it was not worth the risk. So, I just adopted the single engine method, with one engine in the ET, offset towards the orbiter.

BTW - even with a single engine in the ET, the offset distance is key. The heavier the orbiter weighs compared to the rest of the “stack”, the more the engine mount needs to be offset towards the orbiter. This is even more critical for a minimized fin system such as I used. The old Estes shuttle’s plug-in fin system is more tolerant of an imbalance, to a point. Of course the Estes shuttle also was done presuming a certain range of mass for their orbiter.

For my models, I had to find out where to locate the engine mount in the ET the hard way. Build pretty much the whole model, except for gluing on the aft dome and of course not installing an engine mount. I rigged up a temporary bulkhead taped into the front end of the ET tube, and this temporary bulkhead had a clear plastic window glued underneath, with some grid lines. Separately, I rigged up a pointed dowel to be mounted upright on a table, with the point of the dowel standing high enough that the entire shuttle stack could be placed onto the point of that dowel, with the point visible thru the clear window. So, I used that whole “rig” to find out where the lateral balance point was on the model, as regards the Z axis (+Z towards orbiter, -Z opposite orbiter). I added a 1/8” balsa standoff to the -Z axis of the ET, near the top, and allows a piece of thread to hang down off of it, with a blob of clay at the bottom. So, that was a plumb-bob. I shifted the whole stack along the point of the dowel until the thread line (plumb bob) was parallel to the ET tube. When I did find that spot, I marked it on the clear window, and used that distance to determine where the center of the engine mount would be.

Now, I left out a couple of details to help get that idea across. Now that (hopefully) you see how and why, here’s what I left out. In the above procedure, the ET nose was not in place, in order to allow seeing the window. Well, I had to account for the missing mass of the ET nose in that step. So, I weighed the ET nose (INCLUDING any noseweight it would end up having), and added simulated weight (a bunch of pennies taped in a roll) to the dead center of the front bulkhead. And, I “guessimated” the mass of the missing aft dome and aft centering rings that would be added later, plus the glue mass, and mass of paint and any details that would be added to the ET/SRB’s. The grand total of the guesstimated mass that would be added later, was all added to the mass added to the center of the temporary front bulkhead.

I should also say that when I did that, the orbiter was already completed, with radio gear, so it weighed what it would for flight. This made for a tricky situation when I wanted to try out a new fin system in 1988, but did not have radio gear in the orbiter. The rest of the shuttle stack was still what I had built in 1984, I replaced the 1984 Estes type fins and tested out one fin on each SRB at 45 degrees. Since the radio gear was not in the orbiter (in another model by then), the ET would have needed a different thrustline for the engine mount. But, it would have been too much of a hassle to re-do the ET mount. So, what I did was add dead mass to the orbiter to bring it back to what it used to weigh.
72BP_flight1988.JPG

The above image is the 1988 test flight of the 1/72 model that proved out the single fin on each SRB stability. The bright spot on the bottom of the ET, near the orbiter, is the exhaust flame from the virtually smokeless exhaust of the old Aerotech F15 engine that it flew on.

Now, it gets even a bit more complicated if the orbiter is supposed to glide. The “up” elevons will tend to try to make the shuttle stack pitch nose-up on boost. The ideal solution to that is to rig the elevons so they can be flat for boost and come up for glide. But that may not be practical, such as for using the North Pacific/Guillow’s orbiter. So, for those it could help for that perfect lateral balance I described above, to be made a bit imperfect, so that the thrustline would be a hair closer to the orbiter so as to cause the stack” to pitch down a little bit to counteract the pitch-up force of the elevons. But, that could also be addressed by positioning he shuttle so that the “belly” of the orbiter faces into the wind, so that the wind will try to pitch the model into it from weathercocking (as usual), to counter the pitch-up for the elevons. Also, if the fins are more like the old Estes shuttle, or the Dr. Zooch shuttle fins, it will not be affected as much (it is the one fin on each SRB type fin system that is really sensitive).

- George Gassaway
 
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Thanks for the synopsis of your R&D effort...

I love reading about design methodology and testing....

I imagine you and Matt Steele could write a comprehensive article about your Space Shuttle designs and flights at those NAR competitions.

I have a 1/48th scratchbuilt RC Shuttle that I planned on taking to the local club field and ferrying it up on my Telemaster, or a Bill Winter Cloud Niner...
Haven't gotten a club volunteer to step up and offer to team up on the flight with me though....I can't fly both.

I do intend to eventually put it up on a rocket powered carrier...my internal debate was whether to go with something scale like , or just say to h*** w/that and devise a much simpler "non scale" carrier for a parasite flight....
 
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If you really like the “flying” part, and want to fly it a lot, then piggyback is the way to go.

Because for a given amount of money for engines, you can get a piggyback orbiter a lot higher than you can get a full stack. By say a 3:1 margin. Or to flip it around, you can fly the orbiter to the same altitude as the full stack for a whole lot less money

My first free flight orbiters flew on piggyback boosters. Even the 1/110 shuttle I made in 1979, it did not fly very well (about 200-250 feet on a D12, as it was heavy). So eventually I started flying the 1/110 orbiter on the same booster I had originally used to fly the 1/80 orbiter I had built in 1977.

My first R/C rocket boosted orbiter was 1/72 scale, based on Luther Hux’ plan in Model Aviation, but built lighter (and as per his plan, the wing area was increased a bit to fly better). First flew in fall 1982. The piggyback booster for it was minimized in design to reduce drag and mass (seen in middle pic at bottom of message). Powered by staged D12’s, though I also later built a second carrier for it that used a 29mm engine mount for F15 power. The design of the booster made used of two tubes, one just under the orbiter for the engine mount, then the main tube blow that. The exciting charge blew forward, then thru 90 degree tunnel connected to he other tube, then out the back of the other tube for rear-ejection. When the chute deployed, that let the orbiter fall off. Unfortunately in 1988 the shock cord broke, so the orbiter never came off, and the whole thing plummeted to the ground, smashing the front end of the orbiter.

Two stability design elements of that booster. For one, two ventral fins, in a “V” opposite of the orbiter. Those were needed to help give the whole vehicle good stability in yaw, to avoid yaw/roll coupling problems (same reason why a 4 finned rocket will not do well if you fly it with one fin missing). Also, a fiberglass shaft for the nose section, with about an ounce or 1.5 ounce of noseweight at the very front end. That moved the CG far enough to be stable, especially with a second D12 hanging out the back at liftoff.

In 1992, I built another piggyback orbiter. Larger, at 1/60 scale, and with the wings a bit bigger than scale. I designed it to work with the then brand new Aerotech G12 reload in the 32mm RC case. I used a similar type of booster design, with the two ventral fins, and the boom plus noseweight design (seen in last 2 pics at bottom of message). For the boom I used 3/8” square spruce. The G12 has no ejection, but that was fine. Because after the crash of the previous model due to a shock cord, this new model was going to have a 3rd channel for sepping the orbiter by R/C (same R/C sep method my 1984 full Stack shuttle used). So for the chutes to recover the booster, I split open a piece of BT-55 tubing to make it into two pieces, and mounted those side by side with the open sides facing directly into the orbiter belly (angled the front ends and added fairing ramps to make them aerodynamic). One chute plus shock cord is stored in each of those two split tube halves. So, when the orbiter seps, the chutes fall out and deploy. It worked out very well. For the engine mount, I put the engine behind the orbiter, so it would not tend to have a severe pitch-up problem if the engine was mounted even with the orbiter, at the back end of the belly. It meant it needed some extra noseweight but that was a good design tradeoff.

I have flown that dozens and dozens of times. When flown on a G12, and the boost is good, it will climb to about 700-800 feet and glide for about 70-80 seconds. At NARAM-34 near Las Vegas, it hit a thermal and flew for over 3 minutes.

So this brings us back again to full stack versus piggyback. My 1/72 full stack shuttle, the entire flight is done in 25 seconds or less. So that is 20 seconds max for glide time. Barely time to set up a heading alignment circle to set up for landing (pretty much sep from ET is the start for landing approach). With the Piggyback orbiter, I usually get at least a minute of gliding time, since it boosts so much higher.

Key to all is lightweight.

Here is a YouTube video of one of the piggyback 1/60 orbiter flights:
https://tinyurl.com/yef77ma

Photos below, left to right:

Free Flight 1/110 orbiter on special piggyback booster.

Tom Beach’s version of the same 1/110 orbiter on an Alpha-ish type booster.

First R/C rocket boosted orbiter (1982), at 1/72 scale, with its unique minimized booster.

1/60 piggyback orbiter (1992) about to leave the rail. You can see the left-most ventral fin sticking out, the other is hidden (they are angled outward at about 30 degrees from each other). The dark rectangular object to the right of the fin, under the orbiter, is the 32mm engine mount. If you want I can try to dig out the piggyback booster and get some better pics of the design details.

1/60 orbiter being prepared for flight. I simply hinged the bay doors as one unit, on one side, for simplicity. In this shot, I am manually setting the locking mechanism that holds the orbiter in place. I found out the hard way not to try to use the servo directly to lock the orbiter on. Instead, the servo slides out a release pin that is holding a locking lever arm in place. With the pin gone, a rubber band pulls to rotate the locking lever arm out of the way, releasing its grip on a special notched pin on the booster.

- George Gassaway

Shuttle-Piggyback.jpg

GAFF3.jpeg

Scans172.jpg

Scans118.jpg

WSMC-1994-Shuttle1.jpg
 
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Well, that said, I'm going for the piggyback first.

I need the altitude...and as they say in RC...it's good to be "several mistakes high" when testing...and a full stack doesn't look like it would give me the altitude I'd get from the piggyback ride....that G12 altitude looked pretty darn nice by comparison.
I'd like to try and replicate your piggyback booster if I can get some more detail on that George...

A drop test from a plane is what I'd like to do.
Won't be happening soon unfortunately...I need that copilot.
So......I can go it alone ........with the non scale lift rocket.

I used to watch Luther Hux do his thing at the Arcola field back in the day. His wife Dawn used to take the sticks while he flew the shuttle...he had a very nice twin engine lift aircraft to do the chore.

Unfortunately...my wife won't qualify for flight test.
 
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Well, that said, I'm going for the piggyback first.

I need the altitude...and as they say in RC...it's good to be "several mistakes high" when testing...and a full stack doesn't look like it would give me the altitude I'd get from the piggyback ride....that G12 altitude looked pretty darn nice by comparison.
I'd like to try and replicate your piggyback booster if I can get some more detail on that George...

A drop test from a plane is what I'd like to do.
Won't be happening soon unfortunately...I need that copilot.
So......I can go it alone ........with the non scale lift rocket.

I used to watch Luther Hux do his thing at the Arcola field back in the day. His wife Dawn used to take the sticks while he flew the shuttle...he had a very nice twin engine lift aircraft to do the chore.

Unfortunately...my wife won't qualify for flight test.

Come to pole green and train me. I have flown some stuff before. Show me the ropes, ill be a copilot :p

Ben
 
Well it sounds like piggyback is the way to go if I want to get the orbiter up there. I wonder about a Dyna-soar atop a titan type configuration... Ted
 
Well it sounds like piggyback is the way to go if I want to get the orbiter up there. I wonder about a Dyna-soar atop a titan type configuration... Ted

Don't worry. Jim will get his full stack. Hes got some work ahead of him making a 1/10th scale Space Shuttle orbiter but hes got time.

Ben
 
I was just going through an old box and found a spare external tank cone for the estes set (with the glider orbiter). I dont think ill be using it so if anyone really needs on let me know. lw
 
George, I just want to say that these posts about your experience with modeling the space shuttle have been extremely enlightening and very helpful.

And that drawing of the full-scale shuttle stack is a *fantastic* resource!

Thank you for your contributions to this thread, to TRF, and to the hobby as a whole.
 
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