Estes Blackbird Idea

[rocketman]

I was recently given an Estes Blackbird, one that han't been launched since 1980! :eyepop: (well at least to me, it's strange having a rocket older than I am ). I looked at the back end of the rocket, and noticed that there were three holes, one for the engine, and another two empty. (see picture attached =)
I was wondering, could you put an engine in each of the three holes, and fly it as the BEST CLUSTER EVER op:. How would I go about doing this? Recommended engines?
EDIT: Picture is, well, erm.... upside down. Still, you can see the holes I mean =)

 

[Silverfish]

It is possible to cluster it, as I have seen it done. I remember a thread dedicated to your exact idea, but just cannot find it...

 

[skip_dye]

Yes it can be flow as a cluster, but there are a few items to consider:

1) The two engines in the pods will move the CG back. You'll have to add nose weight to make it stable.

2) If the two pod motors ignite before the center motor gets a chance ignite, you will be looking at a lawn dart recovery. You need the center motor to light so it will deploy the parachute.


It a risky flight, but looks impressive if you pull it off.


Alan

 

[Micromeister]

I was recently given an Estes Blackbird, one that han't been launched since 1980! :eyepop: (well at least to me, it's strange having a rocket older than I am ). I looked at the back end of the rocket, and noticed that there were three holes, one for the engine, and another two empty. (see picture attached =)
I was wondering, could you put an engine in each of the three holes, and fly it as the BEST CLUSTER EVER op:. How would I go about doing this? Recommended engines?
EDIT: Picture is, well, erm.... upside down. Still, you can see the holes I mean =)

Been flying my SR-71s 3 motor clustered for years. I've warn out 3 or 4 models but did Crash the first when the core motor failed to ignite. Since that first model I've learned to vent the outer boosters into the main generally flying the model with a core C6-5 or 7 with 2 C6-7's in the boosters.
adapting the outer pods for motors does require a little effort capping the plastic intake with Stainless steel tape clay plywood discs to prevent melting and working rectangular brass tubing into Vents that can be spliced into the balsa spacer parts.

It is an Awesome flying model with 3 motors. Great boost on the outer two...but the landing sucked canal water! LOL!!!

 

[Verna]

I was recently given an Estes Blackbird, one that han't been launched since 1980! :eyepop: (well at least to me, it's strange having a rocket older than I am ). I looked at the back end of the rocket, and noticed that there were three holes, one for the engine, and another two empty. (see picture attached =)
I was wondering, could you put an engine in each of the three holes, and fly it as the BEST CLUSTER EVER op:. How would I go about doing this? Recommended engines?
EDIT: Picture is, well, erm.... upside down. Still, you can see the holes I mean =)

We've done it and it flies great. It doesn't take much to make it a 3 engine cluster.

Before you paint, all you need to do is:

1. Add enough clay to bring nose cone weight to 2.1 ounces and your cg/cp will be fine.

2. 2 engine blocks - 1 for each nacell.

Before you glue the nacell nose cones and tail cones on, use a spent engine casing to install an engine block exactly 2" from the aft end of the nacell bodytube. This should allow the engine to extend out of the tailcone, about 1/8th " after everything is installed. Use the spent casing to push the engine block into the aft end of the nacell tube exactly 2", then glue the engine block in place. Later, install and glue in place the nacell nose cones.

3. Enlarge the aft end both tailcones slightly using an engine casing to gauge the size. I sanded down the "aft end" of the cones until they would allow the engines to go in easily, but not too large. It doesn't take much sanding.

When you have the correct fit, glue them in place.

*When the nacell cones are the correct size and engines are in place the nozzles will protrude about 1/8th " out of the installed tail cones.

*You will friction fit the nacell engines - no hooks in the nacells.

4. Drill 2, 1/8ths holes, 1" from forward end of nacells, on opposite sides, to vent the "burn through" gases of the boosters.

I like to fly ours on 2 B6-0's and 1 B6-4.

I'm attaching some flight photos too.

Verna
www.vernarockets.com

 

[tibadoe]

Now that's tough looking!

 

[rocketman]

We've done it and it flies great. It doesn't take much to make it a 3 engine cluster.

Before you paint, all you need to do is:

1. Add enough clay to bring nose cone weight to 2.1 ounces and your cg/cp will be fine.

2. 2 engine blocks - 1 for each nacell.

Before you glue the nacell nose cones and tail cones on, use a spent engine casing to install an engine block exactly 2" from the aft end of the nacell bodytube. This should allow the engine to extend out of the tailcone, about 1/8th " after everything is installed. Use the spent casing to push the engine block into the aft end of the nacell tube exactly 2", then glue the engine block in place. Later, install and glue in place the nacell nose cones.

3. Enlarge the aft end both tailcones slightly using an engine casing to gauge the size. I sanded down the "aft end" of the cones until they would allow the engines to go in easily, but not too large. It doesn't take much sanding.

When you have the correct fit, glue them in place.

*When the nacell cones are the correct size and engines are in place the nozzles will protrude about 1/8th " out of the installed tail cones.

*You will friction fit the nacell engines - no hooks in the nacells.

4. Drill 2, 1/8ths holes, 1" from forward end of nacells, on opposite sides, to vent the "burn through" gases of the boosters.

I like to fly ours on 2 B6-0's and 1 B6-4.

I'm attaching some flight photos too.

Verna
www.vernarockets.com

Thanks for the detailed instructions Verna! Wow, every question I've ever asked on this forum has got a fast, detailed, helpful reply. Thankyou everyone!
However, the Blackbird was given to me painted and built. Is there any way I could still convert it?
Thanks in advance,
Tom

 

[Verna]

If you can remove the tailcones without crushing them, the rest will be easy and even if you mess them up you can fly it without tailcones, just move the engine block forward a bit so the engines aren't so far out the back.

We almost always get 2 of anything we but. One to tinker with and another one or two for spare parts. You could use the one you have now to experiment on and then build a really nice one from a new kit with all the bells and whistles.

Verna
www.vernarockets.com

 

[dragon_rider10]

Verna, Micro, et al. I think an Estes SR71 Gallery in the Gallery Section would be a great addition. I didn't get any photos of mine before the 'event'. Would one of you be kind enough to start the thread with one of your Blackbird mods?