Finally a Complete Orbital Transport Build Thread...

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rosko_racer

rosko_racer

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Pulled my PDR Orbital Transport last night, set up a table and a lamp in the living room, and got to work on the OT while watching Iron Man on HD... The movie rocks!!!

So far I have done the main wings of the booster, installed the MM with a nice kevlar/elastic cord combo for shock cord, set up the LLs on their stands, set up the glider's "holding" dowel on its stand, glued the glider's fins together and then to the glider's BT, and glued the NC of the glider... Not bad for a couple of hour's work. Pictures will be posted later.

I am contemplating using sanding sealer I recently acquired at a bargain price on all balsa parts for a smooth finish. Paper laminating would be faster and easier but I want to try the sanding sealer. I hope it does not add any significant weight that it changes the glider's flight performance...

As I recently mentioned on an earlier thread, I plan on painting the OT Tamiya Mica Silver.

Any advice is welcome.

More later... :)
 
If your using Midwest Sanding sealer or balsa filler you should be ok raul.

Sanding sealer really doesn't fill grain very well (it's not really designed to) that's what balsa filler is designed for but you can after many many...many coats get it to fill the grain. Balsa filler has way more "filler solids" in the vehicle then sanding sealer. Sealer is just that; it seals the wood..not fill the grain;) I added a pic of the balsa filler i've been using below....Great stuff tho it just stinks to high heaven:D:D
Back when I was using this stuff extensively, I'd apply 3 coats, letting it dry well between coats. Sand away with 120grit paper to start, backing down to 240, 320 to 600 as I neared bare wood. It usually took at least 2 triple coatings to completely fill all balsa grain to a very smooth finish.
While these sealer/fillers do add a little to the overall weight they are also dope so they doesn't add all that much weight.
I have to warn you....even my very very tolerant better 2/3rds can't really take the smell of either Sanding sealer or Balsa filler, they have a very stronge Acetone, Lacquer thinner stinch!
Hope this helps.

Balsa Filler 70-4-sm_3oz jars Pactra & Midwest_03-26-07.jpg
 
The smell of balsa sealer:eek:
I am the unlucky one balsa filler has never really worked for me. I use 4 to 6 coats of balsa sealer and all the grain is gone with minimal sanding with 320 grit. I am restoring a DRM right now and I am using the original Pactra Aerogloss sealer and it seams to fill faster than the new stuff. I used the sealer on my OT with no real added weight. You mention that would were thinking about papering the fins. It seams to me that if I didn't want to go through hassle of filling and sealing I would use bass fins. I have never done this so I don't know how much of a weight issue this would be. I have painted basswood and I know it comes out real smooth.
 
I Agree with scigs on using Basswood for the vertical tails, strakes and even the fake motor housing surrounds.

I'd leave the main wings and tips, along with the glider wings balsa.
Use of Basswood on the lesser parts could save yourself a good amount of work and gain some "sleekness" by using thinner Basswood on those areas. If the wings are 3/32" balsa, maybe 1/8" can't quite remember...you could easily use 1/16" or even 3/64" basswood for the lesser parts which would be just as strong but be a little more aerodynamic without a weight penelty, especially the booster motor housings, vertical tails, wing stiffener strakes, canards, belly fins and glider suppports:)
Finishing basswoods tight grain is so much easier then filling and finishing balsa.
 
I'm with Scigs regarding the balsa sealer. I prefer it over the filler.... which seems to take just as many coats as the sealer does, IME. But you may want to rethink the choice not to laminate...of course, it might be too late. The wingtips and surrounding areas seem to be the weakest point for me with this design. That always seems to be the first part to make contact with the ground during recovery, and can be subject to breakage. Laminating those areas should help strengthen the balsa. I'm not sure I see a need for basswood on this, but I guess it's an option. I used sealer on the original one I built in the early 80's. It took some time to sand, but it was all part of the process, and a good reminder of why it was rated a skill 4!
 
Thanks guys for those great tips! The sealer I was talking about is SIG brand. Never used it before... I do not remember using sanding sealer or balsa filler in the past.

I have not touched the OT yet. All I have done is what is on the picture.

I may go with laminating, it makes sense to add some reinforcement to the fins. The only thing is when to laminate: before adding the scram jets or after... I can gently trace and remove the paper from the wing on those areas where the housing of the scram jets are to be glued so there is balsa-to-balsa contact. Something to consider which will definetly increase the building skill level of this.

Ah, and if you ask where did the MM came from: I removed that one from another rocket that I got from Scott during one of his give-aways at NARHAMS... did not feel like using the parts this kit came with.

Talking about the recovery system, Can this be made to recover with the BT on the horizontal?

OT-001.jpg
 
I've launched mine maybe 6-7 times, and the lower left vertical stab has broken clean 3 times. It always separates at the attach point. I'm not sure basswood would give enough surface area for a good bond.

Mark
 
I also have problems with the vertical stabilizers breaking off of the main vehicle. The idea thing to do would be to put tabs on the bottoms of the vertical stabilizers that would extend just to the bottom of the main wing, create the corresponding slots in the main wing.

Maybe we can convince Carl to incorporate this into an "SLS Orbital Transport". The BT-60 based 168% upscale is quite sluggish on D's, and besides Hawk's Hobby already offers one. Sooo... how about a 136% upscale (BT-55 main tube, BT-50 glider, BT-20 scramjets)? Should work fine on C11-3s and D12-5s. ;)
 
mach7 said:
I've launched mine maybe 6-7 times, and the lower left vertical stab has broken clean 3 times. It always separates at the attach point. I'm not sure basswood would give enough surface area for a good bond.

Mark
Click to expand...

Yeah, those stabs on the wingtip take a beating for sure. Zooch showed me a neat trick involving rubber tubing and a couple of small dowel sections. Basically you make these little curb feeler thingies that attach under the wing. They hit first and absorb some of the impact. Sort of Mars Lander like, but without legs and rubber bands.:cool: I have yet to try it, but the idea is pretty sound. Just looks little funky with the dowels hanging off the rear.

Raul, I laminated and glued everything right on top. Might be a mistake, but we'll see. Those scram jets weigh almost nothing and will add very little stress to the paper. And, the booster never lands on those, from my experience. I just like having the paper to draw on when it comes time to make the alignment marks.:) You can see there's not much balsa to fill now, but still plenty left to do before primer. The glider will get very light filler and paint. You can also see the little balsa reinforcement strips I added to the wingtip joints, underneath. I'm hoping these will help sure things up and reduce the chance of damage.

OT Wing Lamination.jpg

OT Tip Lamination.jpg
 
Foose:

If you ever try the technique from Dr Zooch post pictures... sounds interesting.

I will definetly add the balsa reinforcement strips to my OT. One thing about the laminate: right now I have the wing and the vertical fin glued (waiting for the glue to completely dry) together. I will then add the balsa strip to the inside/underneithe side of the joint, then paper laminate starting from the top/root edge then all around the vertical fin, towards the underside of the wing... all in one pass. I will then mark where the ram jet housing goes and where the top vertical fins goes, use a sharp X-acto knife to cut out the marks to expose the balsa, then glue the housing and the top vertical fin. Lotta work but it will be fun. I think that wrapping the sticker paper around the fin should help prevent the vertical fins breaking upon landing...

Foose: did you seal the edges of the sticket paper with CA already on your OT?
 
rosko_racer said:
Foose:

If you ever try the technique from Dr Zooch post pictures... sounds interesting.

I will definetly add the balsa reinforcement strips to my OT. One thing about the laminate: right now I have the wing and the vertical fin glued (waiting for the glue to completely dry) together. I will then add the balsa strip to the inside/underneithe side of the joint, then paper laminate starting from the top/root edge then all around the vertical fin, towards the underside of the wing... all in one pass. I will then mark where the ram jet housing goes and where the top vertical fins goes, use a sharp X-acto knife to cut out the marks to expose the balsa, then glue the housing and the top vertical fin. Lotta work but it will be fun. I think that wrapping the sticker paper around the fin should help prevent the vertical fins breaking upon landing...

Foose: did you seal the edges of the sticket paper with CA already on your OT?
Click to expand...

Hopefully the Zooch will see this and post a pic of his OT so you can get a better idea.

That's how I laminated my upscale. I wrapped all the way around like you said. I got lazy this time:eek:

Nope, haven't sealed the edges with CA yet... but I will.;)
 
Man this is an inspiring thread. I am going to get a Semroc OT.
Cheers
fred
 
Hey Craig,

I like the look of your laminated balsa. Can you detail your procedure ? What type of paper do you use what type of glue and how do you attach it ? Weight, clamp anything at all ?


Jim
 
zog139 said:
Hey Craig,

I like the look of your laminated balsa. Can you detail your procedure ? What type of paper do you use what type of glue and how do you attach it ? Weight, clamp anything at all ?


Jim
Click to expand...

Sorry for the delay in responding Jim.

I use full sheet label paper to do my lamination. This stuff can be found at just about any office supply. The store brand works fine for me. Before peeling the backing off, do a "dry" run, arranging pieces to minimize the waste of label paper later. Make sure you're hands are clean and dry, and the work surface is free of any debris. Peel the backing off, lay the sheet flat, sticky side up, and carefully press the balsa pieces on the paper. Trace around the edges if the fins with your hobby knife, freeing the balsa from the paper. Flip the fin over and repeat. I've found the adhesive sticks surprisingly well. But always be mindful of touching the adhesive and keeping it clean! One VERY important last step is to seal the edges of the paper with some thin CA(and sand smooth). I haven't done that to the OT in the pic....but I will. This will keep the paper from lifting up and ensure that no air or dirt gets under the sticker paper. If you think about it, stickers loose their tack from the outside in, not the other way around. You can round the edges, airfoil, etc. before sealing the edges if you want. The label paper will sand right off with the balsa. The adhesive will gum up the sandpaper after a little while, but not too badly. The whole process goes rather quickly. There have been several folks claiming this method doesn't work for them...paper not sticking being the major complaint. I've done many rockets using this method and haven't had any problems.

If not using laser cuts parts and you need to trace fin patterns, laminate both sides of the balsa sheet first Trace fin patterns onto the papered balsa. Much easier to draw on label paper than it is on balsa.;)

Go lightly on the primer when it's time to start painting. The paper will appear to soak up the primer. Avoid the temptation to keep spraying in order to get a full coverage on the first pass. Let the first coat of primer dry completely, use a very fine grit to get rid of any fuzzies. Apply second coat of primer. The next coat of primer should go on a little better, now that the paper is sealed. Use your judgement on whether or not it may need a third coat of primer. Always avoid getting the paper "wet" and saturated with primer or paint. Apply final coats of paint. The finishing technique is really not all that different than painting anything else....meaning, several light coats is better one heavy one.

Let me know how it goes for you, Jim! :)


-Craig
 
I have done exactly what you do Craig, and it works well.
I have also used plain computer paper and "3M Super 77" adhesive (1 can will last a "Long" time).
I just spray the paper (put newspaper around the outside of the paper because the spray is REAL sticky)and stick the fin pieces to it, spray the top of the fins and stick another piece of paper on top. Smooth it with your hands, no clamping or putting books on top needed.
Then just cut them out, sand and seal as you did with the sticker paper. It also works well.
foose4string said:
Sorry for the delay in responding Jim.

I use full sheet label paper to do my lamination. This stuff can be found at just about any office supply. The store brand works fine for me. Before peeling the backing off, do a "dry" run, arranging pieces to minimize the waste of label paper later. Make sure you're hands are clean and dry, and the work surface is free of any debris. Peel the backing off, lay the sheet flat, sticky side up, and carefully press the balsa pieces on the paper. Trace around the edges if the fins with your hobby knife, freeing the balsa from the paper. Flip the fin over and repeat. I've found the adhesive sticks surprisingly well. But always be mindful of touching the adhesive and keeping it clean! One VERY important last step is to seal the edges of the paper with some thin CA(and sand smooth). I haven't done that to the OT in the pic....but I will. This will keep the paper from lifting up and ensure that no air or dirt gets under the sticker paper. If you think about it, stickers loose their tack from the outside in, not the other way around. You can round the edges, airfoil, etc. before sealing the edges if you want. The label paper will sand right off with the balsa. The adhesive will gum up the sandpaper after a little while, but not too badly. The whole process goes rather quickly. There have been several folks claiming this method doesn't work for them...paper not sticking being the major complaint. I've done many rockets using this method and haven't had any problems.

If not using laser cuts parts and you need to trace fin patterns, laminate both sides of the balsa sheet first Trace fin patterns onto the papered balsa. Much easier to draw on label paper than it is on balsa.;)

Go lightly on the primer when it's time to start painting. The paper will appear to soak up the primer. Avoid the temptation to keep spraying in order to get a full coverage on the first pass. Let the first coat of primer dry completely, use a very fine grit to get rid of any fuzzies. Apply second coat of primer. The next coat of primer should go on a little better, now that the paper is sealed. Use your judgement on whether or not it may need a third coat of primer. Always avoid getting the paper "wet" and saturated with primer or paint. Apply final coats of paint. The finishing technique is really not all that different than painting anything else....meaning, several light coats is better one heavy one.

Let me know how it goes for you, Jim! :)


-Craig
Click to expand...
 
Hey Craig thanks for the details I am going to give it a try for sure. Either the Semroc Orbital Transport as you showed pictures of or I just opened a Semroc Mars Lander. I am thinking this would work well for the lander legs for appearance and I am sure it adds some strength also ?

Jim
 
zog139 said:
Hey Craig thanks for the details I am going to give it a try for sure. Either the Semroc Orbital Transport as you showed pictures of or I just opened a Semroc Mars Lander. I am thinking this would work well for the lander legs for appearance and I am sure it adds some strength also ?

Jim
Click to expand...

I went back and forth trying decide whether or not to do this on my Lander legs. Since the CG is so touchy on the Lander, I was afraid the extra weight of the paper might throw it off, so I opted not to. I used a very light coat of filler instead. There may not be any difference in weight, but I was trying to play it safe. It would definitely strengthen the legs.
 
Did some work today on the OT:

- Added a little piece of balsa strip to the wingtip joint like Craig did with his. I used wax paper and modified clothe pins to press the strips until the glue dried. I put some tape over the wing tip and the main wing and used the handle of a sponge brush covered with sand paper and sanded the strip until it was curved. I then covered them with glue to seal and "re-enforced" the inner corner...

- Before applying the glue I laminated the top portion of the wing with sticker paper. First I sanded the top corner of the wing tip as per the instructions. Then placed the wing on the sticker paper and measured how much paper I needed for the top part of the wing. Cut and laminated the top leaving about 1/32 inch of the root of the fin uncovered so that when I apply the fillets some of the balsa is exposed to the glue. Once laminated I cut the excess with a sharp knife. Last step is to rub your fingers over the paper to ensure it sticks to the balsa. One note of caution: take your time trimming the excess or you may cut some of the balsa off... see last caption.

- I laminated it this way so that the paper may provide some degree of strength to the wing tip since it is reported to be one of the weak spots of the OT.

OT-002.jpg

OT-003.jpg

OT-004.jpg
 
Last night I finished laminating both sides of the main wings and completed the ram jets. Removed the sticker paper where the ram jets were to be glued. Laminated the outside and inside of the ram jet housings and glued one of the ram jets to the wing. Last thing I did was to glue the exhaust shroud on the glider and when it was dry I coated it with CA.

ot-005.jpg
 
Good Job Raul:
I've had excellent luck with the mother ship outer wing tip fins by just using an epoies fillet on the inside joint. did this with all three sizes with wonderful results. even after several crashes the 3X upscale never ever cracked a seal on those tips;)

Looks like you've done a bang up job papering. Can't wait to see the bird when shes done.
 
Gentlemen: Thanks for your kind words. I have been on and off with the OT but things around the house and family matters have not allowed me to post pictures but they will be some posts soon.
 
John: I am going to attend the NARHAMS next meeting... I think it is Nov 1st, so you get to see the OT , probably in its primer stage...

Folks, got some time yesterday and today and got a lot done with the OT and the glider.

Caption One: Top and Bottom view of the OT with the glider on. From the last picture posted I had glued the main wings with the top wing fins, the bottom two smaller fins, and the glider's elevons. Did rounded the leading edges of some parts of the fins but still need to round the rest, apply a light coat of thin CA to seal the laminate edges, then resand to make the edges smoot.

Caption Two: Top and Bottom closer views of the wings. I also glued the LLs. The bottom fins remind me of the ones at the bottom of the Interceptor.

Caption Three: Some close ups of the LLs and the Ram Jets. Note that I gave an angle to the leading and trail edges of the LL that hold the glider. I also gave an angle to the LLs leading edge and left the trailing edge square. You can also see the laminate inside the Ram Jets

Glider: It does not have lamination because I am a little concern with weight. It will only get primer to fill in the wood grain with lots of sanding, then it will get its color.

I tested the glider and it sorta glides straight and with a downwards slight angle... I am afraid it may glide straing and a looooong way away from the launch site.

As I was building this rocket I kept thinking: "I thought this rocket was larger"... I really thought this would be a bigger rocket... maybe because I was younger and "smaller" the first time I saw one of these... This really screams for an upscale.

OT-006.jpg

OT-007.jpg

OT-008.jpg
 
Oh come on Raul... We all know what an Orbital Transport looks like. The captions telling us what part we are looking at is overkill! Hurry up and put one of those fantastic Rosko_Racer paint jobs on it!:rolleyes::p:D
 
rosko_racer said:
This really screams for an upscale.
Click to expand...


Looks great Raul. Yes, it does scream upscale. I love my 168%, but a BT55, 136% based booster would be another great upscale. I think a C6-3 or C11-3 would do nicely in one that size.
 
I would like to build the 168% upscale. If the D engine is sluggish would you suggest an E?
 
ron_coffee said:
I would like to build the 168% upscale. If the D engine is sluggish would you suggest an E?
Click to expand...

The D12-3 does fine for boosting the 168% upscale. It doesn't exactly scoot off the pad or anything, but provides a very comfortable boost, say 350-400 ft. I have flown it with an AT D15-4T a couple times and it doesn't seem to achieve any more height than the D12, and the delay is too long. E9 might work ok, but the OT really needs something with a better "kick" off the pad. If our worried about sluggish, E9 is definitely not the answer! Having a decent initial thrust spike in the beginning of the burn is a good idea for a draggy design like the OT. An E11(not sure if it's any better than the E9), E15, or E18 would be better choices, but if your glider is anything like mine, you might not get it back using the 18!
 
Judo said:
That glue is really...yellow.
Click to expand...

I guess that with the white background the yellow glue really stands out!

A quick post to update this thread: The OT and the Glider are ready for painting. The OT may need a little sanding but not much to get it started. That Plastikote primer works great! The fins on the Glider are smooooth! And it sands well... ah, and the smell.... heaven!

OT-010.jpg
 
That is one fine undercoat!
Plasticoat, where does one find it. I would guess an auto parts store?

Mark
 

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