Dr. Zooch Return To Flight Space Shuttle build thread- #2

[Dr.Zooch]

Yep- don't try and really do that... but it's still a pretty cool image

 

[luke strawwalker]

Those are great shots of the orbiter in flight, Fred! I haven't managed to get any good close ups of that little bugger in flight. I have few decent boost shots though. After some minor protest about it not having clear fins by a forum member or two, I took a few liberties with the last photo.

Man, that's KEWL, Fred and Craig!!! Fred you're glide shots look terrific, and I love the photoshop work there Craig, and the 'roll complete' pic... fantastic pic!

We got nearly 2 inches of rain and the ground is too wet to fly mine, and I've been busy with 'work'. Even today, my birthday, I went to run a few simple errands after church and it turned into a complete major nightmare!!!

Why can't people do their freakin' jobs?? (rhetorical) Anyway, I've got to find someplace with some nice longish grass to even trim my orbiter, because it's been so dry the cows have the whole place clipped down like a golf course...

Soon... OL JR

 

[luke strawwalker]

There was some serious engineering that went into this kit, I could tell that when I built it and figured out how it works. The elevator holddown, orbiter mounts, etc. is just ingenious. The only quibble I could mention is that the orbiter is too far forward, but it would be a whole other engineering project to move it back to the 'scale' position, and unless you're flying in front of Wayne Hale and the crew of the lastest shuttle mission, nobody's probably going to know the difference anyway... So even that's not really a 'quibble'.

I'm still not completely sure I understand how it works at deployment, to get the orbiter seperated from the tank with the 'pull up' manuever created by the elevator 'springing' the nose up, without it taking the aft mounts off the tank, but I'm sure it works... certainly design beyond my pay grade!!!

I'm starting on another of the doc's kits but I'll start a new thread for that...

Those are some SERIOUSLY IMPRESSIVE boostervision stills there Doc... How much of an 'addition' did you make to the ET to house the Boostervision, and what did you power it with?? I'd think a standard "C" would be hard pressed to lift a setup like that...

Later! OL JR

PS. I'm still waiting to hear if you guys ever weighed your orbiters and what they ended up weighing, to find out how bad I overbuilt...

 

[foose4string]

Mine is 16 grams. I'm quite sure it's a few grams too heavy compared to the stock version. Looking at the build picks, your shuttle looks none too heavy. You should be fine.

 

[Fred22]

Well I used a smaller motor for photo purposes and I got a deploy on the way down which did strip off the two aft shuttle mounts. It's a very simple fix and well worth what comes after as the glider circles the tank on the way down

 

[Fred22]

This is the end of the sequance up to the beginning of the glide and chute deploy

 

[foose4string]

Well I used a smaller motor for photo purposes and I got a deploy on the way down which did strip off the two aft shuttle mounts. It's a very simple fix and well worth what comes after as the glider circles the tank on the way down

Showoff!

 

[Peartree]

Even today, my birthday, I went to run a few simple errands after church and it turned into a complete major nightmare!!!

OL JR

My experience has been that any serious work attempted on Sunday takes twice as long, costs twice as much, and the probability that something major will break goes up by a factor of ten.

After breaking the tractor at least twice, we gave up and swore we'd never even try to mow the lawn on Sunday.

 

[Fred22]

My experience has been that any serious work attempted on Sunday takes twice as long, costs twice as much, and the probability that something major will break goes up by a factor of ten.

After breaking the tractor at least twice, we gave up and swore we'd never even try to mow the lawn on Sunday.

John I think your words are wise and applicable to any day off
Cheers
Fred

 

[Fred22]

Showoff!

Maybe a little Its neat to be able to refer to pictures though and I flew the heck out of the shuttle as it is so amazing to watch I think Lukes will fly very well and i look forward to seeing pictures of it going up
Cheers
Fred

 

[Dr.Zooch]

The deploy sequence takes less than 1/10th of a second to get the orbiter physically sep.ed from the ET. The actions are all explained by this guy named after a fig bar. At the instant that the ejection carge fires, and I mean before the wadding and chute begin to move, the airframe of the ET has its inertia shifted from forward to retrograde. At that same moment the only thing holding the orbiter onto the ET is friction as seen only in the area where the attach lugs CONTACT the attach dowels. The unbalanced force of the mass of the entire ET plus the inertia of the low-mass orbiter are easily enough to overcome that tiny bit of friction. As the orbiter's forward lug clears the forward attach dowel, the orbiter's angle of attack is shifted by the remaining action between the aft lugs and the aft attach dowels. This pulls it up and away... now- some aerodynaminc interactions between the ejection materials, gasses and equipment will always take place after that point, but the deployment sep. should happen as planned. I have, however, seen cases where some other physical obstructions hold the orbiter on (i.e. a bur on a dowel or paint not fully dried etc).

I've had some who asked if their orbiter may be on too tight. The test there is to attach your orbiter to the ET, the take your arm and swing the stack as if you were tossing a paper airplane really hard, but don't let go of the ET- see if the orbiter deploys. The best you can do in such a toss motion is a speed of about 22-30 mph. At ejection in a rocket boosted flight, the stack can be moving as much as 10 times that speed- the inertias of both components will be increased in kind. Bottom line- it's gonna deploy.

My video stack actually inreases the ET length by about 8 inches (video lesson here folks- what's not in the camera's view- doesn't count). In my first video of the shuttle, it flew on a C6-3 and actually deployed about 10 feet off the ground! The LCO was shouting "HEADS UP!, HEADS UP!" over the PA. I'd switched engines from a C6-5 to a C6-3 just moments earlier... whew! So, now I would advise that an 18mm D engine be used. I've done it and it works just fine.

 

[luke strawwalker]

Thanks for the explanation Doc... makes perfect sense, but when I first cut those dowels different lengths (the longish rear orbiter attach dowels and the SHORT! front orbiter attach dowel) I kept thinking to myself "those rear ones are gonna snap off when the air catches the orbiter as it 'noses up' away from the tank... but then I told myself, "self, you didn't engineer this thing, and you ain't no aerodynamicist (though I play one on TV) and a WHOLE BIG BUNCH of folks have made this thing fly and I KNOW that the Doc did a TON of DDT&E flights on this thing so IT WORKS; I'm just too dim to see the light sometimes, so chill out, finish the job, and get her flying!"

F=MA and so momentum overcomes air drag pushing it back on the pegs... got it. Now it makes sense to me...

Gotta go have another argument with myself about something else

If the wind will ever settle down and the ground dry out a bit I can go trim my orbiter... OL JR

PS... SO KEWL pics there Fred!!!

 

[mjennings]

this is pretty rough, since the cheep kitchen spring scale I have is less than precise.

wt apx 20 grams
CG apx 4 inches from nose just before the wings flare out into the larger delta.

 

[Dr.Zooch]

F=MA and so momentum overcomes air drag pushing it back on the pegs... got it. Now it makes sense to me... [/QUOTE]

Actually... the relative wind (airflow around the moving airframes) is almost neutral, because the ET stack, just prior to the instant of ejection is moving at the same speed as the orbiter.

Although F=ma has a role in all motion, the biggest rule acting here is: "An object in motion will tend to stay in motion in a straight line until acted upon by an outside unbalanced force..." The law of inertia.

Here's a good way to think of it- you're in your car driving to the library with a large book on the passenger's seat (Probably "The History of Manned Spaceflight" by Baker) and you turn a sharp corner and the book slides off the seat. What really happens there? The book's inertia wants to keep it going in your original direction and overcomes whatever friction is between the book and the seat- thus, the book really didn't move from where it was going, rather your car turned out from under it. Now, lets say the book is on the hood and you are going 30 mph on a calm day and your windshield has been removed. You and the car and the book feel the 30 mile per hour wind in your face. Now, you slam on the brakes... The book acts the same in the wind at that instant as it did before and starts to shoot off the hood at 30 mph. If we do that favored thing of physics teachers and "assume a frictionless surface" you'd find that the book heads in it's straight line for a good distance until it's own aerodynamic characteristics are acted upon by the relative wind. In the case of the orbiter, you have a very lightweight object with a very small cross section headed into the relative wind, BUT, (and engineers- hang in there with me- I'm being very basic to illustrate)that relative wind is now in the 200 mph neighborhood, so when we add that into the F=ma formula, we see that the mass is about, .55oz, times 200 which equals a huge force for such a featherweight object- and way more than enough to allow it to move off those dowels just in time to really feel that relative wind. As you can see from the photos of the deploy from fred22, it only gets about an inche off of it's seated position before it pitches way nose up. That attitude is because it has a lot of drag at low weight, but still, the F=ma formula has a role as does the law of inertia.

It's all physics- which scares the heck out of most people- always did me. Then I found that most physics is just looking at something and asking "Okay- what's REALLY happening there?" It doesn't have to be all math formulas either- they're just a language that is used to universally express the actions. You can still put it in common words and not scare people, I've found. What's important for me, is the actual activity as seen using the common laws of physics and some practical aerodynamics. If I need it in math form- I just e-mail my college physics professor... she loves that stuff.

Geee... is this too much information?

 

[mjennings]

If we do that favored thing of physics teachers and "assume a frictionless surface"

That's great! I won't nick pick your explanation it conveys the point with out any math or hand waving.

The math in physics can be scary but getting a grasp of some of the major concepts isn't too hard. Where physics gets bad is when the book / class assumes that you are further along in math classes then you are.

 

[Dr.Zooch]

BTW- I'm going to conduct some tests with the a free elevator and the lugs of the orbiter placed farther forward so as to give the stack a more "real" posture- I'll advise as to the results here.

 

[foose4string]

BTW- I'm going to conduct some tests with the a free elevator and the lugs of the orbiter placed farther forward so as to give the stack a more "real" posture- I'll advise as to the results here.

I'm betting it works. Heck, if the barely there flame fins were enough to keep it stable, then I doubt shifting the orbiter back a fraction will make much difference. I think there is enough weight in the ET cone to make up for it. And, I wonder how much the wings and rudder come into play when stabilizing the stack as a whole? I'm guessing at least a little. Shifting those surfaces rearward would only seem to help. This is something I'm counting when I build the MSC040 stack.

 

[luke strawwalker]

I'm betting it works. Heck, if the barely there flame fins were enough to keep it stable, then I doubt shifting the orbiter back a fraction will make much difference. I think there is enough weight in the ET cone to make up for it. And, I wonder how much the wings and rudder come into play when stabilizing the stack as a whole? I'm guessing at least a little. Shifting those surfaces rearward would only seem to help. This is something I'm counting when I build the MSC040 stack.

Aerodynamically, I agree... shifting the orbiter rearward should only enhance stability. What effects the elevator have, well, it should probably be neutral on the way up and 'deploy' at apogee.... Doing it may require a bit of tinkering...

With enough noseweight you can make nearly ANYTHING stable... NEARLY... LOL OL JR

 

[Dr.Zooch]

Those are the questions we're going to answer. Additionally, the question of flutter on the elevator will be one to address. Most of the boost effects on the orbiter involve oscillation. I did a shot with the stack and a cam aboard in conditions of high gusty winds. An interesting characteristic showed up- the orbiter tends to bounce (in pitch attitude) up and down on the forward attach dowel as it passes through the rough air. In slow-motion, you can tell that each bounce takes place as the stack hits sheer- because the background appears to move (remember- the can is attached to the ET, so the background appearing to "move" indicates the stack being shoved out of its flight path).

Overall- I think Foose is right- it'll fly. The final question will be- does it actually fly "Better" or just the same. Here at Dr. Zooch Rockets one of the mottos is "If it ain't broke- don't fix it." I for one despise it when folks such as I.T. developers take a perfectly functional web site and "make it better." like they recently did at e-bay. So, right now the shuttle flies just fine...

 

[luke strawwalker]

Those are the questions we're going to answer. Additionally, the question of flutter on the elevator will be one to address. Most of the boost effects on the orbiter involve oscillation. I did a shot with the stack and a cam aboard in conditions of high gusty winds. An interesting characteristic showed up- the orbiter tends to bounce (in pitch attitude) up and down on the forward attach dowel as it passes through the rough air. In slow-motion, you can tell that each bounce takes place as the stack hits sheer- because the background appears to move (remember- the can is attached to the ET, so the background appearing to "move" indicates the stack being shoved out of its flight path).

Overall- I think Foose is right- it'll fly. The final question will be- does it actually fly "Better" or just the same. Here at Dr. Zooch Rockets one of the mottos is "If it ain't broke- don't fix it." I for one despise it when folks such as I.T. developers take a perfectly functional web site and "make it better." like they recently did at e-bay. So, right now the shuttle flies just fine...

Oh definitely... I TOTALLY agree with the sentiment (IIAB-DFI). Improvements for improvements sake usually just clogs up the plumbing... Kinda like how NASA developed the moon rocket, lander, and spacecraft in less than ten years in the 60's when EVERYTHING was brand new and untried, with slide rules and pencils, and here we are 40 years later and it's going to take 15 years just to poorly duplicate what we had then, with all the computers and CFD simulations and CAD design, computer modelling, and everything else, and 40 years of experience with what works and what doesn't, and all the corollary advancements in materials, processes, and industry... We've 'advanced' so much we can't do what we did from scratch with sliderules 40 years ago... Sad...

That said, nothing wrong with experimentation and pushing the envelope... that's the only practical way to incrementally advance. NASA unfortunately seems to have neglected that for a long while and is paying the price for it now...

Later and keep us apprised of your findings!!! OL JR

 

[Dr.Zooch]

Just a bit of a side note concerning the above post- I've said for three decades now... "When, the US, Russia or anyone else (i.e. Red China) tries to go back to the moon, they're gonna find that it was NOT as easy as NASA made it look."

Now- back to the shuttle build tread please. For other comments on the return to the moon subject (since it's huge subject and will take us off track here)- let us start a thread in the proper area

 

[Dr.Zooch]

Back on-topic...

This weekend (April 17-19, 2009) MDRA will be holding it's twice per year Red Glare event. I'll be doing some testing on Friday the 17th. One important test involves the Shuttle. It's been reasoned that the orbiter may be able to be set farther back down the stack- i.e. not having the elevator held down by the aft attach lugs, and still boost normally. I now have an orbiter set up to do exactly that.

I'll report back here as to the results- so stay tuned.

 

[foose4string]

Back on-topic...

This weekend (April 17-19, 2009) MDRA will be holding it's twice per year Red Glare event. I'll be doing some testing on Friday the 17th. One important test involves the Shuttle. It's been reasoned that the orbiter may be able to be set farther back down the stack- i.e. not having the elevator held down by the aft attach lugs, and still boost normally. I now have an orbiter set up to do exactly that.

I'll report back here as to the results- so stay tuned.

See ya there Wes. Hope I can catch the flight...should get there mid AM.

 

[Dr.Zooch]

The results were not good.

Back on-topic...

This weekend (April 17-19, 2009) MDRA will be holding it's twice per year Red Glare event. I'll be doing some testing on Friday the 17th. One important test involves the Shuttle. It's been reasoned that the orbiter may be able to be set farther back down the stack- i.e. not having the elevator held down by the aft attach lugs, and still boost normally. I now have an orbiter set up to do exactly that.

I'll report back here as to the results- so stay tuned.

 

[luke strawwalker]

Uh oh... hate to hear that...

Did the stack loop with the orbiter elevators up?? I was wondering if that would happen, as that's a LOT of unwanted 'control input' during powered flight.

I figured a small 'holddown wire' or something would be needed to keep the elevator sprung "down" to neutral until apogee with the orbiter further back on the stack...

Or was it bad things happening because of shifting the weight rearwards?? Tad more noseweight would fix that... but thinking about it I kind of discounted this because the delta wings/rudder should help CP/CG (except for any 'control input' from the elevator of course )

Got any details Doc or are you still 'experimenting' to figure out what happened??

Later! OL JR

 

[foose4string]

I missed Zooch's test flight yesterday afternoon since I had to leave the field early. He said it was "nearly ballistic" when I spoke to him today. However, he used flame fins from a different kit that are smaller than the intended Shuttle flame fins. He didn't realize this until afterwords. The jury is still out. Maybe the larger fins will help.

I flew mine today with the original setup.

 

[luke strawwalker]

That looks TERRIFIC Craig! Man that little sucker looks SO KEWL when it's going up, both on the stack AND gliding!

Got some neat stuff in the works-- I copied one set of the 'upgrade' orbiter wraps you sent me over to 'Paint' and did a few mods on them... Made a TOTALLY new shuttle out of it...

Don't really want to say more until I actually get some cardstock and get it printed off and construction started... But think "007"...

I also have another pet project in the works, requiring a redesigned orbiter nose. I did some experimenting with printer paper at the workbench the other day and have the nose pattern pretty much like I want it... but I haven't started the decoration mods yet, though I DID pop in my DVD sets and get some fairly decent 'screen pics' of the subject....

Can anybody tell me how to do 'screen caps' if I'm playing a DVD on my computer?? The digicam pics of the TV screen paused leaves a bit to be desired... OL JR

 

[aerospike]

Trim tabs on a pair of the flame fins that counteract the pitch created by the orbiter's elevons sound like a solution to me. Another would be to change the angle of attack of the orbiter on the ET so that during boost it's flying at zero lift.

 

[Diosces]

Dr Zooch, It was great seeing your rocket display and seeing some fly at Red Glare 6.

My girls really enjoyed looking at your display.

Check your PM's please I wasn't paying close attention when I gave my girl some money and I think she managed a cut rate price for the Skylab Saturn V kit. I'd like to make up the difference.

Thanks again
John

 

[luke strawwalker]

Trim tabs on a pair of the flame fins that counteract the pitch created by the orbiter's elevons sound like a solution to me. Another would be to change the angle of attack of the orbiter on the ET so that during boost it's flying at zero lift.

Maybe... could probably be made to work, but VERY draggy solution! LOL The AOA method would be a lot more iffy IMHO, because of 'relative AOA' when flying in wind (think of instability/weathercocking/rod tipoff/rod whip type problems)

Simplest solution that comes to mind is to add a small 'engine hook' sort of thing going back from the tank to the elevator to hold it in the 'neutral position' during liftoff and coast, yet still allowing it to slide forward and pop up normally at deployment, allowing the orbiter to retrim for stable glide...

This wouldn't be shaped like an engine hook, more like a "C" hook on the end of a piece long enough to get it to hook over the elevator with the orbiter slid onto it's mounts as it is on the kit... doesn't even REALLY have to be made from metal if that's a concern... could be something like an extra piece cut from the balsa and laminated with paper, like the piece in the kit that holds the elevator elastic on the end of the orbiter (the "C" shaped piece with the groove the elevator elastic slides into, right behind the trim adjust screw) that is glued onto an extra dowel coming down below the tank.

Hard to put into words, but I hope I get the gist across.... have to draw something up and scan it in I guess... LOL

Yall have a good one! OL JR