Apogee TTV Build

[NateB]

Apogee recently released their Timer Test Vehicle, aka TTV. The stated goal is an electronic staged rocket which can be flown on inexpensive motors on small fields. This sounded perfect for me. I want to learn about staging composite motors and anything I can fly in the local park is a bonus. I ordered the kit and it arrived 2 days earlier than first estimated by USPS.



First up, I downloaded the instructions and Rocksim file from Apogee. I'll be modifiying the sim file in Open Rocket as I go, but starting with the provided file.

 

[NateB]

There are quite a few parts in the bag, so be careful opening it. The included ebay secures the flight computer on one side and serves as an ejection baffle on the other. Parts are laser cut plywood and cardboard and fit together nicely. The instructions call for CA glue, I might go back over each joint with wood glue to ensure everything is well sealed to protect expensive electronics.

 

[dvdsnyd]

Looking forward to your build and thoughts. It looks like a fun kit to gain experience staging composite motors.
Looks to be highly engineered and well-refined!

 

[mh9162013]

I will be watching this thread closely.

 

[Hobie1dog]

Apogee has their act together

 

[NateB]

Looking forward to your build and thoughts. It looks like a fun kit to gain experience staging composite motors.
Looks to be highly engineered and well-refined!

I have barely started, but everything so far appears to be very well thought out with a clear purpose. The build instructions are well written and easy to follow.

 

[Cape Byron]

I watched the first of the Apogee build videos this morning. This is a really well thought out kit. I might have to find a place in the US to send kits to and then ship a big bunch here at once.

Yes, this is a kit I actually want and it’s not a vintage glider.

 

[mundayr2]

I just ordered the kit myself. Please keep us posted on your build.

 

[NateB]

For those following along, read the instructions for the next steps carefully.

A cardboard coupler is split in half and joined end to end to cover the length of the AV bay with the ejection baffle behind it. The laser cuts made separating the parts easy. Note the small pieces which are discarded.


The coupler halves slide over the plywood sled. I dry fit everything before gluing to see how each part fit together. Each piece is glued with wood glue per the instructions, being careful to keep the edges flush.



As the coupler is slid onto the sled, glue is only placed on the edges for this step.


Plywood disc A is the glued into place, be very careful to keep the sections of cardboard coupler flush with each other.



Seal the seam between the split coupler with thin CA. I also added some small filets of wood glue on the seams on the plywood sled.

 

[NateB]

I assembled the motor mount this morning. No tricks or special instructions here. I thought long and hard about using a Rocketatrium 18mm motor retainer and it appears there would be room in the transition used as the inter-stage coupler. I decided against it mostly because I didn't want to add to the cost of this build and wait for shipping.



The chipboard disc has a tab cut for the motor hook. This was a tight fit on the outside of the motor mount tube. It may need light sanding or to peel part of rhe glassine off the motor mount tube.

 

[NateB]

I continued work on the sled and motor mount assembly today, I also ran into a few hiccups.

Parts were cut out of the carboard and laid out.





I dry fit the support pieces and centering ring with the sled and also with the motor mount. I noticed that centering ring J was upside down and 1 of slots for the support F and G pieces didn't line up. This is an easy fix. I just cut the tab off which didn't align right and glued the support flush to the CR. Nobody would know if I didn't just write about it. Thin CA was wicked into each joint.

The next step was add a tube to guide the ignitor for the sustainer. The kit includes a paper straw which was a tight friction fit in each hole in the 2 centering rings and the sled. The holes are lines up perfectly thanks to the laser cut pieces, but the paper straw was too flimsy to insert through the three holes without getting crushed. I tried reinforcing the ends of the straw with CA, but it was still weak. I ended up using a piece of aluminum tubing that just fit the holes without any further modification. Easy enough to fix.

 

[cerving]

For those following along, read the instructions for the next steps carefully.

A cardboard coupler is split in half and joined end to end to cover the length of the AV bay with the ejection baffle behind it. The laser cuts made separating the parts easy. Note the small pieces which are discarded. View attachment 593627
View attachment 593628

The coupler halves slide over the plywood sled. I dry fit everything before gluing to see how each part fit together. Each piece is glued with wood glue per the instructions, being careful to keep the edges flush.

View attachment 593630
View attachment 593631
As the coupler is slid onto the sled, glue is only placed on the edges for this step.

View attachment 593632
Plywood disc A is the glued into place, be very careful to keep the sections of cardboard coupler flush with each other.

View attachment 593633

Seal the seam between the split coupler with thin CA. I also added some small filets of wood glue on the seams on the plywood sled.

View attachment 593634

I did something like that a long time ago when converting an Estes rocket into dual-deploy. I used much larger shoulders, though, a large switch band covered the opening and the booster and payload sections just slipped right over the shoulders.

 

[NateB]

The transition piece needs a simple modification to serve as the inter-stage coupler. Just cut the angled portion of the shoulder off and sand the lip smooth.


Next I strengthened the lower portion of the fin can tube with thin CA. The instructions then state to sand the inside of the fin can and the shoulder of the inter-stage coupler to a slip fit that ensures the coulpler just falls out of the fin can under its own weight.

Now the motor mount / sled assembly needs tacked into the sustainer fin can. The upper portion of the sustainer body tube slides over the sled and is held in place with a plastic rivet.



The fin can should just fit around the tab.


Next the motor mount is tacked into place with a couple of drops of CA just between the aft centering ring and the fin can body tube. I then removed the upper portion of the body tube.



A small bead of thin CA is then wicked around the joint between the red coupler and the fin can.

 

[NateB]

Everything else on this rocket is pretty standard to build.

The sustainer fins are sanded and punched out from the Basswood sheet.



I rounded the edges with an NCR guide. This picture didn't turn out well, but I think most know what to expect. Basswood shapes nicely and is stronger than Balsa. I really need to use it more.


When dry fitting the fins, there is a slight gap. Some light sanding on the fin tabs fixes that.



Fins are attached by spreading wood glue along the fin root and both sides of the tab. I insert the fin, remove it, and double dip the glue. I hope this builds up a decent fillet against the motor mount and centering rings.



Later today, I'll make the external fillets with Titebons Quick and Thick glue.

 

[bad_idea]

Thank you for the detailed build log. The more I see of this kit, the more impressed I am by the thoughtful elements of its conception. As I said in another thread about this rocket, in a world where most kits are merely styled, a kit that's actually engineered is a breath of fresh air.

 

[NateB]

Thank you for the detailed build log. The more I see of this kit, the more impressed I am by the thoughtful elements of its conception. As I said in another thread about this rocket, in a world where most kits are merely styled, a kit that's actually engineered is a breath of fresh air.

You're welcome. It is a great kit and I am enjoying the build.

 

[NateB]

Fillets with Titebond Quick and Thick are nice and simple.
Lay down a small bead of glue.



Smooth it out with a finger dipped in water.



If you want to build up a larger fillet, let it dry and go around again.

 

[NateB]

I am moving on to the booster now, this assembles like any other kit. The kit includes 2 lengths of kevlar shock cord. The thinner cord is used on the booster and the thicker cord will be on the sustainer.



Pencil marks are drawn on the motor mount for the engine hook and after centering ring. The engine hook is 1/4" away from the forward end of the motor mount. The aft centering ring will be 3/4" from the aft of the motor mount. Loop one end of the shock cord around the motor mount and tie it off.



Dry fit the forward centering ring first so the fin tabs will fit between the centering rings. I like the notch so the shock cord loop doesn't interfere with the centering ring.



Last for now, the centering ring and thrust ring are glued into place. While this was drying, I rounded the edges of the booster fins the same as I did on the sustainer.

 

[NateB]

I didn't get too far this evening, but I did glue the motor mount into the booster. As usual, a scrap of wood is useful to reach into the body tube with a dab of glue for the forward centering ring.





Looking forward, this kit includes launch lugs for a 1/4" rod. I don't have that size of rod, so I am debating about making standoffs for mini rail buttons instead. There is plenty of scrap Plywood or Basswood from the kit to make a standoff or I could print some rail guides.

 

[NateB]

The through the wall fins on the booster are attached in the standard manner as well. One the glue is dry, I will add fillets using Quick and Thick just like the sustainer.




There are just a few small steps to wrap up before I will move to paint and the electronics. There is an included cardboard bulkhead for the inter-stage coupler.



It simply rests on a lip on the small end of the transition and is glued into place with thin CA.

 

[c0c0m0ke]

I got my TTV over a month ago. I quickly had it together and was playing with the timer, but I failed to figure out how to read or understand the flashes it was giving me. I have read the instructions many times, and counted out the flashes as the Timer goes thru its' routine. So far, I think this is what is happening.

I think I missed the battery recommendation, if there was one. I assumed a 9-volt battery would be sufficient, but it is actually too big to fit into the ebay. Once I figured that out I went back to the Apogee web site to order something that would fit. I didn't measure the available space, and I didn't read the specs, I just read the current and picked something I thought would work. I struck out. Neither the 400 mAh nor the 900 mAh will work for me. The 400 mAh fits but doesn't have the juice to fire the Estes igniter, while the 900 mAh is too big to fit in the gap you are given. So I am on their web site as they announce a new battery for the TTV, it is the"7.4v 2-cell Battery."

With the new battery installed:

At "Start up"the green LED comes on SOLID for a few seconds. Then both the RED and green are SOLID for a short period of time. They both go out, then the Green LED flashes 10 times, followed by two short flashes and 4 more. There is a pause, both LEDS come on for about 3 seconds (first program opportunity here) then the green LED flashes 10 times followed by 8 flashes a pause and two more. Both LEDS light up again for about 3 seconds (second program opportunity here) and the both LEDS quickly alternately flash for about 3 seconds (this flashing sequence is when I am to test either T for timer and A for apogee, or both A & T. That s my understanding. Do I have that right? If I don't press the "test" or "program" button (it is the same button), it goes into "launch detect mode' - the green LED is on SOLID. If I tilt the rocket (ebay) once it gets to or past 45 degrees from vertical, the RED LED comes on while the green goes out.

I think I should be using some other type of igniter, something other than Estes. Star Tech igniters (initiators). I understand that the Quest igniters require more voltage or amperage. I have a variety of other initiators, but I have no idea how to measure the resistance. for the different types I have.

I am going to take my time testing what igniters I have with this Timer. The Estes brand isn't working for me at this time.

Has anybody else tried different igniters or initiators, or starters? What would you recommend?

I think ithis is the battery to have. You need a special charger for it. Read the instructions. It might take more than one reading , I have the impression, English is not the native language of the manufacturer.

c0c0m0ke

 

[waltr]

Check MJG BP starters
https://electricmatch.com/rocketry/see/23/6/bp-rocket-starters
These are Ematch based and easy to fire.

 

[NateB]

Thanks for the information about the Apogee Simple Timer and Battery. I'm planning on using a Blue Raven for the first few flights and also letting this kit live up to its name as a test vehicle for a Quantum or other electronics.

 

[NateB]

I used Quick and Thick for the external fillets in the same way as the sustainer.

I have been debating about using rail buttons or the included lugs and decided to include both. For the booster launch lug, the standoff is glued to the body tube first. There are nice lines etched into place by a laser to make alignment easy. I found the the Basswood strip liked to bow one glue was applied, so you will want small clamps while it dries.

 

[NateB]

The AV bay is designed around the Apogee Simple Timer, which I am not using. There is plenty of room for a Blue Raven, but the terminal block on the Power Perch does not fit without modifying it. The orientation of the Simple Circuit from Additive Aerospace fits with plenty of room for battery options and wiring.



A push button switch is included and an access hole is already cut out of the fin can body tube section. The instructions state to use thick CA to secure the switch. My bottle of CA decided to glue itself shut, so I used regular 15 minute epoxy.

 

[kjhambrick]

That's a pretty AV-Bay, @Nate B

Thanks for the pictures !

-- kjh

 

[NateB]

Work, family needs, and too high humidity to paint have delayed finishing this project. Fortunately with the school year underway and the weather improving, I can wrap up this project and go launch it.

I decided to pull the push button switch. I tested it several times with the Blue Raven and the button was sticking quite a bit. I didn't notice a bounce which would cut power to the altimeter, but I wasn't sure how well it would work with vibrations during flight and general wear over time. I'll be using a Fingertech micro screw switch in its place. I used one of these on another small DD build and it works well.

Launch lugs are glued in place with wood glue. I used a small section of aluminum tubing to ensure they are straight. I didn't have a 1/4" launch rod, so I picked up a a 6' length at Menards for a few dollars. I might cut it down so that I end up with 4' of usable guide length once it is mounted in my launch pad.

 

[TXJeff]

I've got mine built and tested... Its ready to go. But everything has conspired to keep me from attending launches for months now. :-(

 

[bad_idea]

I've got mine built and tested... Its ready to go. But everything has conspired to keep me from attending launches for months now. :-(

Hope you make it out soon. What club do you fly with?

 

[FurqWerx]

I just finished this build. It was one the more difficult builds I have ever done. My laser cut ebay/baffle parts were a little askew so I had to finesse it a little. But it eventually went together very well. I was shorted one 3 inch launch lug but Apogee very quickly sent me two. Now I just need to paint it. I love this rocket. The design of the ebay/baffle is really beautiful.