BD 4" Tyrannosaur Build - L2 cert

As demanded on my what to buy thread - https://www.rocketryforum.com/showthread.php?70132-What-a-good-level-2-kit

I purchased:

Binder Designs 4" Tyrannosaur w/E-Bay
AeroPack bright aluminum tail cone
Perfectflight Stratologger
Bear Altimeters AltiMulti & Alti Duo kits
Aerotech J425-14A Redline 38 mm - DMS
85 pack of ematchs off ebay - for deployment charges

First I have to say that Mike @ Binder Designs puts together a very solid kit. The Instructions seem to be very inclusive with many good tips and warning. Got a guy that hasn't build a HPR in 25 years, this looks like it should be a fun build.

After spending the last week pondering epoxy choice, fillers, researching deployment altimeters, deployment charge methods, etc, I thought it was time to First clean up the work bench in the garage then get started.

My first panic was weather or not there was enough motor mount tube to extend out to for the AeroPack Tail cone that required 1.875" from the bottom of the body tube. After measuring and test fitting, I figure I have just enough, as in the Top Centering ring will be at the end of the tube. A little closer than I'd like, but it will work... I'm sure of it.

Night 1:

JB Welded AeroPack Retainer body to MMT & Epoxied lower Centering Ring




sanded rounder edges on to lower fin set



Next problem.... The AeroPack tail cone (work of Art BTW) seats into the end of the body tube by 1/16" so the lower Centering is high taking up some of the fin slot:



I'll have to ponder that one for a bit, and that's where I left it this morning.

Bright idea to solve my find clearance issue.... I need 1/8", so trim 1/16" of for and after end of find. I had a good sharp finish blade in the power miter saw, so that was easy.

Was able to get lower fins all mounted and left the first set of internal fillet curing:

View attachment 188309

hopefully I can get epoxy on the next side in the morning, then the final in the evening....

op:

I'm down for this build... Which Aeropac retainer did you go with? I'm looking for a specific part number with regards to the type tubing you have.

DRAGON64 said:

I'm down for this build... Which Aeropac retainer did you go with? I'm looking for a specific part number with regards to the type tubing you have.

Click to expand...

If you have a Binder Design 54mm motor tube, you need the 54mm "L" version.

jpoehlman said:

As demanded on my what to buy thread - https://www.rocketryforum.com/showthread.php?70132-What-a-good-level-2-kit

My first panic was weather or not there was enough motor mount tube to extend out to for the AeroPack Tail cone that required 1.875" from the bottom of the body tube. After measuring and test fitting, I figure I have just enough, as in the Top Centering ring will be at the end of the tube. A little closer than I'd like, but it will work... I'm sure of it.

Click to expand...

I forgot that the tailcone requires the motor tube be extended so far out the back otherwise I would have given you a few extra inches. Glad that it will just work out though.

Any plans on the paint scheme? My wife gives me a bad time about our latest models color schemes being too bland, I did paint the Tyrannosaur prototype with a hammered bronze though, and who has a brown rocket anyway?:eyeroll: I tell her that the customer can paint them any color they want and she replies, "But they never do, they always paint it exactly the same as the one on the website!"

Anyway, feel free to go crazy with some color, I'm sure it will look great!

DRAGON64 said:

I'm down for this build... Which Aeropac retainer did you go with? I'm looking for a specific part number with regards to the type tubing you have.

Click to expand...

I ordered for AeroPack:

TA5439LA - Tailcone Retainer Assembly, 54mm MMT to 3.9" AF, L, Aluminum

This fit Binders' 54MM Motor Mount tube perfectly.

I liked it so much I ordered a standard retainer for a LOC 3.1": RA38L - Retainer Assembly, 38mm, L

and added an adapter to use with this build: A3854 - Adapter Assembly, 38-54mm

At least each order came with a free sticker.... I need to stop the spending thought!

Binder Design said:

I forgot that the tailcone requires the motor tube be extended so far out the back otherwise I would have given you a few extra inches. Glad that it will just work out though.

Any plans on the paint scheme?

Anyway, feel free to go crazy with some color, I'm sure it will look great!

Click to expand...

No worries on the tube length, it's going to work.... I didn't even think about it until I started to test fit the pieces.

On paint, good or bad, I let my kids help chose the colors and scheme. We have a Gold Metallic Quest Big Betty, a Bright Silver Estes Crossfire, and a LOC 3.1 x 7' with a Bright Silver NC, Dark gray metallic body and fins...with 2 Red fins on 1 side.

My 5 year old and I where at Home Depot today. He picked out Hunter Green, Red, and Metallic Blue. Not sure the scheme, or if these colors will stick if we end up at the Auto Parts store again in the paint isle..... In any case, I don't think it will end up like your prototype.

I have plenty of work before then.

Binder Design said:

If you have a Binder Design 54mm motor tube, you need the 54mm "L" version.

Click to expand...

jpoehlman said:

I ordered for AeroPack:

TA5439LA - Tailcone Retainer Assembly, 54mm MMT to 3.9" AF, L, Aluminum

This fit Binders' 54MM Motor Mount tube perfectly.

I liked it so much I ordered a standard retainer for a LOC 3.1": RA38L - Retainer Assembly, 38mm, L

and added an adapter to use with this build: A3854 - Adapter Assembly, 38-54mm

At least each order came with a free sticker.... I need to stop the spending thought!

Click to expand...

Thanks for the info, I appreciate it.

With all the lower fins having a fillet on at least 1 side, I started on the upper fins. Wanting the upper and lower fins to be in exact alignment, I looked around the garage and found two near perfect scraps of Red Oak hard wood. Clamping the Red Oak onto the lower fin left a slot to to place the upper fin into and keep it in line while the epoxy cures. I also had 2 issues. 1) of the 3 fins, 2 are 6MM thick while the 3rd is 7+MM....just enough to make the precut slot too tight. 2) the length of the precut slots was needed a little extending to get the fins to fit.



My electronics are all in now. I'm starting to think about how I want to setup the E-bay.

jpoehlman said:

I also had 2 issues. 1) of the 3 fins, 2 are 6MM thick while the 3rd is 7+MM....just enough to make the precut slot too tight. 2) the length of the precut slots was needed a little extending to get the fins to fit.

Click to expand...

Sorry about those issues with your kit. Those fins were all cut from the same sheet of 6mm ply, I've never seen that amount of variance in the tolerance especially in the same sheet. The plywood we use is the highest grade of aircraft plywood they make.

The slots are usually short just a bit mostly because they are CNC cut with a rounded bit which leaves a radius, and secondly for fine tuning of the fit by the builder. I prefer to do it that way rather than make the slots longer.

Mike,

Do you have a RockSim or Open Rocket file for this kit?

Binder Design said:

Sorry about those issues with your kit. Those fins were all cut from the same sheet of 6mm ply, I've never seen that amount of variance in the tolerance especially in the same sheet. The plywood we use is the highest grade of aircraft plywood they make.

Click to expand...

Thanks for the follow up Mike. I don't blame you for the thickness variance, why would you have a need to check? I have no concerns and am very happy with the quality of you product! It was just bugging me that 1 of the 3 fines Upper and lower where not easily going on the pre-cut slot and I had to figure out why.

Binder Design said:

The slots are usually short just a bit mostly because they are CNC cut with a rounded bit which leaves a radius, and secondly for fine tuning of the fit by the builder. I prefer to do it that way rather than make the slots longer.

Click to expand...

If I remember correctly, you even cover this in the instructions....that the slot may need to be trimmed a little for clearance. It's nice to have such a tight fit!

I just hope I can make the finished product match the initial quality of the kit! This think is going to be fun to fly.

jpummil said:

Mike,

Do you have a RockSim or Open Rocket file for this kit?

Click to expand...

If Mike doesn't have it, I'm happy to share the OpenRocket file I've build for this.

Not a lot to report as far as progress....

The final upper fin is set and curing as of now. Next up will be to trim the small tubing tab between the upper and lower fins, remove the fin can, and complete internal fillets one side at a time.

Here's the final fin in it's set position:



I did get to a hobby store over the weekend to purchase some addition components:

3/16" plywood for E-bay tray
Brass tubing to e-bay tray sliders
.015 brass sheet to strengthen and assist with shear pin action

I also pulled a link out of the archives on a very interesting fillet finishing technique: https://www.skypirate.net/rocketry/con_fil_01.htm
I may have to try that out.

Until next time.....

jpoehlman said:

I also pulled a link out of the archives on a very interesting fillet finishing technique: https://www.skypirate.net/rocketry/con_fil_01.htm
I may have to try that out.

Until next time.....

Click to expand...

How ironic you linked to that. I came up with a PVC pipe fillet a long time ago. My link is listed in the additional resources at the end of that tutorial. I can't believe that the free angelfire page I created about 15 years ago is still up: https://www.angelfire.com/or2/fisherrocketry2/ Mine is a little different, I don't pull pipe through the wet epoxy, I press it in until it squeezes out, then tap the pipe off with a hammer after it cures. I've used bondo and JB Weld with good results. With enough rubber bands I can do all of the fillets at the same time.

Progress has been slow with holidays and colder weather (working in garage). I have completed all the internal filets and I-bolt attachment:



I did attach a OneBadHawk Kevlar harness with a 1/8 quick link prior to installing the fin can in the lower body tube:


Last action was to install the fin can in the lower body tube and tape around the bottom of the tube to secure while curing.

Looks like it's time to move on to fillets that will be seen.

Oh, I did solder together the logging bear altimeter... still need to test it and the Perfect flight SL100.

Un-decided if I'll use that combo, or the EEggFinder TRS I got for black Friday..... decisions decisions.