Stuffing the Ranger Tube

[Scode68]

Was looking at the instructions for the Estes Ranger and was wondering if there was a better way of blocking the BT off around the motor tubes? The ranger is basically a Big Bertha with three BT-20 tubes for clustering A-C engines. I could try some plywood I guess.

 

[Scode68]

Thanks!

 

[Quasar]

You could use an RA-2060 centering ring like the Scrambler did.

https://www.spacemodeling.org/JimZ/k-37.htm

 

[ScrapDaddy]

MARKII HAD A BETTER RESPONSE (i removed mine

 

[MarkII]

The tissue and glue method actually works quite well. It sounds worse than it is. One alternative to the tissue, though, is to use inexpensive 1-ply paper napkins. A bag of cotton balls is another. Buy a LARGE bottle of white glue. Don't worry - it's cheap.

First, mask the lower end of the tube as you would if you were painting. You will be able to grasp and hold the tube without worrying about getting gooey fingerprints all over it. Roll a sheet or two of printer paper around it and seal the edges with a delicate release type of masking tape, such as Tamiya or Duck Brand Perfect Release.

Use a small disposable plastic bowl or recycled food container. Pour in enough white glue to form a decent puddle. Tear up the paper into little pieces and drop them in and mix. Keep adding paper until most, but not all, of the glue is absorbed. The paper should be quite soggy but not dripping. Then just pick some up in pinches and stuff it into the tube. You want it to be somewhat soggy so that it remains wet when you are applying it. If it starts to set up while it is still in the bowl, it will be harder to work with.

You will probably need to mix up a few consecutive batches in order to get all of the spaces stuffed. Don't worry about getting all of them nice looking and perfect, though, because you have a secret weapon that the kit instructions never mentioned. Once you have stuffed in enough of the mix to basically block the spaces, set the tube aside to let it dry.

Then mix up some 30 minute epoxy. (The slow curing kind works better for this step.) Stand your tube up with the motor end up and drip some epoxy onto each paper-filled space. I pick some up on the end of a craft stick and drop it/spread it onto the paper stuffing. Use enough to get all of the spaces evenly and completely covered and filled to the same level, but not so much as to weigh down the rocket too much. Slow-curing epoxy self-levels nicely and forms solid, smooth bulkheads around the motor tubes. It creates the ultimate seal; the paper stuffing provides support for it. When you paint the Ranger, you can brush paint these bulkheads so that they look nice.

MarkII

 

[BEC]

The ranger is basically a Big Bertha with three BT-20 tubes for clustering A-C engines. I could try some plywood I guess.

This is off topic, but actually, it's the other way around. A Big Bertha is a single-engine Ranger....

 

[Micromeister]

Have to agree with Mark the tissue and glue method is a simple and effective way of blocking the small opening between tubes in a BT-60 18mm three motor cluster.

I've used this method with plain old elmers white glue, yellow carpenters glue, Tite-bond II and even Alene's. Tissue can be just about anything from real jap tissue (expensive) to facial tissue ( makes a mess but works). personally I perfer plain old white packing tissue.. the kind you get in cloths boxes. Works wonderfully.

Because the motor mount BT-20 tubes fit so snugly in the BT-60 all that is really necessary is to close the rear of the tube to prevent gas leaks. this doesn't take nearly as much as you might think. Stuff it in the openings to completely close the rear end but don't try to fill the entire long space. just enough to close perhaps 1/2" or so.
In a pinch i've used 5minute epoxy and plain old school notebook paper but that's a story all unto itself. Point is to try to keep it as light as possible while sealing off the rear end. As mark mentioned it is possible to finish off the rear surface with 5 or 30 minute epoxy after the glue stuffing has set up but it you use a little care with a damp finger with the white or yellow glued paper it'll dry pretty smooth. a coat of two of primer is generally all that's needed to really straighten out the look

Don't forget the tiny triangle between the three motor tubes. I found if I'm using 3 spring clip retainers with these set ups I seal off the forward end of the center before installing the motor tubes.

Big thing is not to be afraid of this process it isn't that bad, and really works well. Trying to Cut close fitting filler plywood pieces like this just doesn't work well.
Hope this helps.

 

[gpoehlein]

This is off topic, but actually, it's the other way around. A Big Bertha is a single-engine Ranger....

Close - the BB is a single engine Ranger without the payload section!

I should also note that it is one of my favorite rockets to fly - great fun on a set of Quest A6-4 motors (nice and smoky!!!)

 

[BEC]

Oooops - right! I should've known/remembered that .

 

[Scode68]

Close - the BB is a single engine Ranger without the payload section!

I should also note that it is one of my favorite rockets to fly - great fun on a set of Quest A6-4 motors (nice and smoky!!!)

Thats kind of what I meant and the smoky Quest A6-4 cluster sounds cool.

I was kind of thinking along the lines of the stinger but the more I here you guys talking about the tissue and glue the more I want to try it.

I also notice on Uncle Mikes that the Cygnus triple 18mm mount in a BT60 is like the one used in the stinger.

 

[green dragon]

The tissue and glue method is best and easiest - I have used that even for HPR builds.

One change I make, and just used this week on my ARG T117-3, is I stuff a wad of paper towek or tissue down in the tube holes, then add drops of thin CA til it saturates the paper, then let dry - this coats the tissue through and through and sets fast, and MUCH less messy.

then I fill the spaces with wood glue or wood putty ( or epoxy works well, too ) .

tada, nice clean filled in spaces and cosmetically good, too.

~ AL

 

[MarkII]

I used the tissue and Elmer's white glue method, followed by a light layer of 30 minute epoxy on my Cobra clone. As for the center triangle, I epoxied a 4-40 blind nut into it at the upper end of the motor tubes, then covered all but the threaded hole with small bits of JB Stick (epoxy putty) to insure that it was well-anchored. I did this after I had glued the three motor tubes together but before I had bonded the cluster into the airframe. Then I soldered an acorn nut and a #4 fender washer onto one end of a length of 4-40 threaded rod. The threaded rod is my retainer for the three motors; when it is screwed in, the washer overlaps the edges of all three, keeping them from being ejected.

Fender washers (actually, fender-style washers) in size #4 are not very common. I obtained mine from Micro Fasteners.

MarkII