Terrier-Orion Two Stage Conversion

So, I've undertaken to modify a Quest Terrier-Orion into a two stager, representing its namesake.
Quest Terrier-Orion
NASA Terrier-Orion

I started with thinking and designing, thinking, redesigning, procrastinating, more thinking, and more redesigning over a couple of years. And now I've finally begun building. And then I got more than half done before I thought to take some pictures for a build thread, so here's the best I can do.

The basic concept is to use rear ejection in the booster, propelled by the ignition charge while the sustainer is being lit. To accomplish this, I've left the motor mount floating in the aft end of the booster, and lengthened it to meet a fixed extension tube that ends about 1/2 inch short of the sustainer motor. This extension is held in position by two vented centering rings, which will allow gas to progress down into the main volume of the booster. The booster airframe is not vented; the role usually played by venting is played instead by the expanding volume inside the airframe as the motor mount slides out. The fixed extension includes about 2-1/2 inches of coupler on its aft end; thus, contact is maintained between the mobile motor mount and the extension for some time as the motor mount begins its exit.

I was compelled to make a couple of on-the-fly modifications during the build so far; once I have updated my RockSim design accordingly I'll post it.

Here's the RockSim file.
View attachment Terrier-Orion Two-stage.rkt

And here are the early pictures.
Sustainer motor mount installed:
Ejectable booster motor mount:
Booster extension from the top, with one vented centering ring visible:
I got the centering rings from BMS. Looking at them in place, I think I may need to drill out bigger vent holes.

I look at this and think; the upper stage motor is going to ignite and blow your floating MMT out the back without separating the two stages. The sustainer motor will burn through the booster tube while the boosters chute will deploy, with the two sections still coupled.

You are asking for three entirely separate events to occur pretty much simultaneously, sustainer motor ignition, staging and booster chute deployment all caused by one event; the blow-through of the booster motor.

This is going to be a real balancing act between the various forces.
Good luck, I look forward to seeing a video of its flight.

boomtube said:

I look at this and think; the upper stage motor is going to ignite and blow your floating MMT out the back without separating the two stages. The sustainer motor will burn through the booster tube while the boosters chute will deploy, with the two sections still coupled.

Click to expand...

Well, anything's possible. I will have the upper stage fit somewhat (but not very) loosely on the tip of the coupler. The most likely failures I see are that the booster's motor mount does not push back far enough to release the streamer (and the booster probably survives anyway) and/or the plastic transition melts. But I'm trying it all the same.

boomtube said:

You are asking for three entirely separate events to occur pretty much simultaneously, sustainer motor ignition, staging and booster chute deployment all caused by one event; the blow-through of the booster motor.

Click to expand...

Not "entirely separate" by any means. The blow-through and sustainer ignition are equally capable of accomplishing separation. And deployment is linked to ignition, since the venting that's usually used in ignition is replaced by the action of the motor mount pushing out; that is, if it works for ignition then the motor mount will move, and I just need to hope it moves enough. (I'll pack the streamer low, so the motor mount doesn't have to come completely free.)

Now, if separation happens too soon then ignition will likely fail and streamer deployment certainly will, so the "balancing act" is all down to the sustainer-to-transition fit.

And, indeed, it may not work; if I had an iron clad solution I would have stopped dithering and started building over a year ago. But after all the attempts at making the design better, short of adding electronics,* I finally decided it was time to defecate or get off the pot.

boomtube said:

This is going to be a real balancing act between the various forces.
Good luck, I look forward to seeing a video of its flight.

Click to expand...

Me too.

* As an EE, I'm not really afraid of adding electronics, but it's a bunch of weight going up on 2 C motors, and it just seems "more right" to do low power without that. Maybe after this I'll build one in 38mm.

jqavins said:

Well, anything's possible. I will have the upper stage fit somewhat (but not very) loosely on the tip of the coupler. The most likely failures I see are that the booster's motor mount does not push back far enough to release the streamer (and the booster probably survives anyway) and/or the plastic transition melts. But I'm trying it all the same.

...

Now, if separation happens too soon then ignition will likely fail and streamer deployment certainly will, so the "balancing act" is all down to the sustainer-to-transition fit.

Click to expand...

This is what I reckon to be the most likely failure mode. With no vents to release the gas produced by the burn-out of the booster motor's propellant, that gas will push the motor mount and sustainer apart. If the sustainer is loose enough to release cleanly then it's probably loose enough to be blown off by that gas.

Here's what I did with my multi-stage Rheinbote. The coupler to the next stage consists of a tube which fits loosely over the upper stage's motor mount tube plus a centring ring to match the inner diameter of the upper stage body tube. Behind the centring ring is a short Nomex streamer. This isn't enough to be a recovery device, but it doesn't have to be - most boosters just tumble down anyway because they're unstable. A long booster like this is likely to come down ballistic, so the streamer simply destabilises it.

This is where a little “Dry Slide” graphite lubricant can come in handy. The last thing you want is to have Stiction occur when and where you don’t want it. Dry Slide goes a long way to overcome that problem without being greasy, which can in itself produce “Stiction”, of flammable.

I often burnish the booster coupler and the inside of the sustainer body tube into which the coupler fits with this stuff.

What you would need to do is determine which moving parts you want to move first and which parts you want to stick around a bit longer.

boomtube said:

This is where a little “Dry Slide” graphite lubricant can come in handy. The last thing you want is to have Stiction occur when and where you don’t want it. Dry Slide goes a long way to overcome that problem without being greasy, which can in itself produce “Stiction”, of flammable.

I often burnish the booster coupler and the inside of the sustainer body tube into which the coupler fits with this stuff.

What you would need to do is determine which moving parts you want to move first and which parts you want to stick around a bit longer.

Click to expand...

Graphite is wonderful stuff. I use it on the couplers of all my stagers.

boomtube said:

This is where a little “Dry Slide” graphite lubricant can come in handy [etc.]

Click to expand...

That is a terrific idea; thank you! Offhand, I think that where I'll want it is on the booster motor mount to assure it slides first. That means inside the top of the long motor mount tube, where it will cover the coupler on the bottom of the extension, since the extension itself will be pretty much unreachable. Also the inside of the booster tube, so that the floating centering rings float freely. This should ensure the motor mount gets far enough to release the streamer, while the long coupler keeps the path up to the sustainer engine intact for a little while (which is why I designed in the long coupler in the first place.) Then the sustainer ignition will push off the booster. Just a little bit of stiction there should actually help things happen in the right order.

So, thanks again for the wonderful suggestion. I will get me some graphite forthwith.

Fins, fins, and fins.

Faces filled and sanded, edges sanded flush, ready for shaping:
Shaped, new surfaces filled and sanded:
And, glued to the tubes and filleted:

Tomorrow I'll drill larger vent holes and put the pieces together.

Today (so far) I've drilled out 10 of 15 of the vent holes from 1/8" to 3/16". The centering ring was not a great fit to the tube and was not firmly against the wall part way around, so I avoided drilling there. Te holes are somewhat messy, which is what I get for having them cut too small in the first place. Still, this increases the venting area by about 80%.

Then I got ready to glue the transition on top, but I test fitted it to the sustainer first and found it was too tight. Some sanding took care of that. I took before and after pictures, but you really can't see any difference.

In an attempt to get the joint between the coupler and booster tube really well filled and seamless, I placed filler in the coupler before gluing it in place so I'd get squeeze-out, then scraped that off flush.

After it's had plenty of drying time I'll do a bit of sanding around and we'll see if this has done any good. (I've also scraped the schmutz out of the grooves on the transition after I took the above.)

And speaking of filling grooves, does anyone have any advice on the spiral grooves of these Quest white tubes? They're too big to ignore, but so small I can't get any filler to stay in them. The best I can figure is to let them fill up with primer, but that'll mean a lot of spraying and sanding; there's got to be a better way. A certain brand or type of filler? A technique I ought to know?

Any updates???

TopRamen said:

Any updates???

Click to expand...

I'm afraid not. I got busy moving, and the garage/workshop still isn't unpacked. I'll provide updates once I'm back in operation.

I'll be watching this, as I'm starting to develop an Interest in this style of rocket. I have an Estes Centuri on its way to me now.

After too long a hiatus, I've started building again. The first thing I wanted to do is a ground test of the staging, which is the biggest risk for this build. But, I discovered I had left out the shock chord that attaches the ejectable booster motor mount to the booster airframe. D'OH! that would have been easier to do earlier in the build.

I worked a piece if piano wire through the holes in the vented centering rings and out the bottom of the booster then attached a Kevlar chord with a drop of CA, and pulled the chord up.

A big fat knot in the top keeps the Kevlar from going back down through the holes. I then found that the chord was not long enough, so I extended it with elastic. (Both pieces were extras from a Quest kit.) A new hole drilled through the upper centering ring on the motor mount allowed me to pass the elastic through then tie it off around the tube.

Mission accomplished.


I've also attacked cradles to a bar clamp that I can use to hold the sustainer suspended over my deck railing. I now await the simultaneous possession of time, energy, and good weather to carry out the test. I'll post video when I do it.

Well, we had an eventful hour or two of testing. "Eventful" is not a good thing, but in the end we had a highly tarnished success. The videos and picture tell most of the story.[video=youtube;p161fgNRYf4]https://www.youtube.com/watch?v=p161fgNRYf4&feature=youtube_gdata_player[/video][video=youtube;TfDCMmeXess]https://www.youtube.com/watch?v=TfDCMmeXess&feature=youtube_gdata_player[/video][video=youtube;0Ut-9Fg02Zo]https://www.youtube.com/watch?v=0Ut-9Fg02Zo&feature=youtube_gdata_player[/video][video=youtube;OpZXUO9fzBw]https://www.youtube.com/watch?v=OpZXUO9fzBw&feature=youtube_gdata_player[/video][video=youtube;i8YZgD473Sk]https://www.youtube.com/watch?v=i8YZgD473Sk&feature=youtube_gdata_player[/video]The RemainsThe cato was my fault. It was suggested, after the first test, that I should add a smidge of loose BP to get more sparks forward. I knew it was risky, I knew what might happen, my gut said it was a bad idea, and I did it anyway. No one's fault but my own.In the post mortum analysis I concluded that the test was actually a success. Consider: 1) the sustainer motor lit. B) The booster separated without melting the plastic reducer that's serving as the coupler. And III) the motor mount was ejected before it blew up (or else the booster airframe would not now be intact.) So it was a successful proof of concept, and once I repair the damage and rebuild the motor mount I'm confident it will work.

Repairs are under way.

The orange fin is from the wreck of my first Quest TO. That one was build exactly according to the instructions, nose weight and all, made its maiden launch on the recommended engine, and promptly took a sharp turn off the launch rod and crashed. I salvaged what I could for parts, including the fin I'm using now.

Only the "Dead battery" video works.

Crap! I'll try to fix it. Weird, though, 'cause I uploaded and linked them all tthe same way.

The videos are fixed.

Any static test of a model rocket that doesn’t involve the local Fire Dept should be considered a success.

Here’s something you might try so as to increase the likelihood of igniting the sustainer motor from the booster’s “Blow-through”.

Install a BT-5 tube running from just forward of the booster motor’s mount’s thrust ring and ending just below the sustainers open nozzle. Using a couple of heavy cardstock transitions liberally soaked in super thin ACC, on either end of the tube to channel and concentrate the gasses upwards and into the forward motor’s nozzle.

As for the humongous spirals; thin down some Elmer’s wood filler to the consistency of mustard and apply using Motile Organic Phalangeal Environmental Modification Devices.

Sand smooth using Flexible High Friction. . .Sand Paper.

Repeat as necessary.

boomtube-mk2 said:

Any static test of a model rocket that doesn’t involve the local Fire Dept should be considered a success.

Here’s something you might try so as to increase the likelihood of igniting the sustainer motor from the booster’s “Blow-through”.

Install a BT-5 tube running from just forward of the booster motor’s mount’s thrust ring and ending just below the sustainers open nozzle. Using a couple of heavy cardstock transitions liberally soaked in super thin ACC, on either end of the tube to channel and concentrate the gasses upwards and into the forward motor’s nozzle.

Click to expand...

I'll keep that in mind. Based on the sparks emerging from the top of the booster in the third video I really don't think there'll be a problem in the next test (after the rebuilding.) But if there is, I'll do something like this. (Probably I'd rebuild the whole booster, with the existing stuffer arrangement done with a piece of BT-5 attached directly to the engine block, and the fixed part being a long BT-5 coupler in the vented rings. That way there's no need to construct a funnel.)

If you use BT5 chimney you may want to smear a bit of epoxy on the inside of the BT5 for 2 to 3 inches just above your motor. Otherwise some residual flame that burns for a few moments in you lower stage after ejection will burn up your BT5

Hi, i recently built a Quest Terrier Orion and modified it to a real two stager. The second stage ignition is done by a piston/capacitor/microswitch/igniter. First stage and second stage descend on streamers.
Two succesful flights on C6-0/B4-6 and D9-0/B4-6 were done on FTTS-6, a recent launch event of the Dutch DRRA. See my build-blog on the DRRA website

https://drra.nl/drra_shop/showarticle.php?art_id=1560&rubriek=JouwBouwBlog

Hi, in october i flew this one again on Estes C6-0 and B4-6. The streamers were replaced by small (Topflight) parachutes. This time the launch was less succesfull: the rocket came of the launchpad too slowly, being not stable enaugh. Result was a nearly horizontal flight after leaving the guide rod. However: all systems worked properly: 2nd stage ignited and flew horizontally and was never found again. First stage itself separated properly and both halves of the first stage did land on their chutes properly and undamaged. So 2nd stage was lost, but he more complex 1st stage including ignition system and chutes was recovered. The same week a new 2nd was built, so model is complete again.

The furst flight with an Estes C6-0 was a Lucky shot: Estes advise is max. 113 gram startoff weight. I think it is best to use a Klima D9-0 which can handle 300 grams. Or maybe a Klima C6-0 with 160 gram. The startoff weight of the loaded missile is 160 gram. Next launch planned april 2016.

Estes rating is an average. Your first launch could have been a beefy C6, while the flat flight might have been a real wimp.
Over the years, you can almost tell the way a rocket you've launched several times before leave the rod, if it's a Schwarzenegger or a DeVito.
Order up a 6' SS rod from Graingers, that will help in any case.

I had a friend convert an LPR version to 2-stage about 15 years ago. It might have been an Estes kit. He said that it was very difficult to get the electronics into the forward end of the first stage.

Really cool conversion!

Looks very similar to the lines of the old Centuri Excalibur, I have been thinking about making a two stage conversion of one of those. Here is an article on staging, with some tips on gap staging.
https://www.apogeerockets.com/Tech/How_2-Stage_Rockets_Work
I have never tried it before. I was thinking to help keep the sustainer stable with the smaller fins up front on the Excalibur, was to build the transition cone so that it remains attached to the sustainer rather than the booster, this gives a little extra cone drag stability to the upper stage.

@Woody, i think you are right about this variation in engines. Before first launch i really had doubts about using the C6, so the first launch was with a Klima D9-0 which is capable of lifting 300 grams. Next launches will be again with this D9 engine.
@Glen, i know the priciple of gap staging, but personally i do not like this technique because of its decreasing reliability with the increasing distance. I think the Klima engine has a clean burn, and contrary to black powder motors they probably do not produce enough hot sparks to ignite the upper stage. And in this model there would be no nice recovery method for the first stage when using the gap stage principle. In my Terrier Orion the 2nd stage is ignited by the charge of a small capacitor (charged shortly before launch, on the pad), connected through a microswitch to a bridge wire igniter. The switch is operated by a small piston which is pressed by the exhaust of the 1st stage motor. The piston only moves 2 mm, the rest of the exhaust pressing the two halves of the first stage apart. Both halves have their own small parachute. Check the DRRA-pages link. It is in Dutch, but several pics are in the article...