Custom ATW

[JAL3]

A while back, I picked up some old OOP 13mm Estes adapters in a lot on Epay. I put one together and wanted to give it a try.

I tested out the motor adapter on a Custom Rockets A.T.W. It is a light rocket which always performed well with 1/2A6-2s. I inserted a 1/4A3-3 into the adapter and then slipped the adapter into the tail of the rocket. It was a bit loose so I applied some tape to improve the friction fit.

The rocket launched, underpowered, arced over and hit the ground. Then ejection occured. Thankfully, there was no damage to the rocket.

This ill fated flight can be seen here: https://flickr.com/photos/23694991@N03/3282372275/

 

[JAL3]

Even though the first flight was not a good one, the adapter seemed to have worked as advertised and I wanted to give it a second try. This time I loaded a 1/2A3-2.

The flight was much better but problems began at apogee. Instead of ejecting the streamer, the charge ejected the motor mount. The rocket came down ballistically, glanced off the GSE truck and hit the ground. The only damage was some minor crumpling of the BT.

A video of the second ill fated flight can be seen here: https://flickr.com/photos/23694991@N03/3282374535/

 

[JAL3]

This rocket is chronicled in photos and video here: https://flickr.com/photos/23694991@N03/collections/72157613861597912/

 

[JAL3]

As I mentioned, after its last flight, the ATW was a bit banged up. The worst was some crumpling of the BT where the NC fits.

 

[JAL3]

Instead of trying to splice on a piece on new tube, I decided to just shorten the whole thing. I figured that with all the fin area, there would be no problem with stability.

I inserted a mandrell, delimited the area to be cut with some tape and then drew a razor around it until it came loose. The piece was discarded and the end was strengthened with thin CA.

 

[JAL3]

While working on the BT, I noticed that 3 of the 4 fins had been glued back on at one time or another and that I had never bothered to clean up the paint. I decided that today was the day to do it.

 

[JAL3]

Amazingly enough, I actually remember that I used Testor's OD for the original paintjob. I did not have any on hand, however. I took out a bottle of Tamiya enamel and decided that, while not perfect, it is better than nothing. I brushed it over the fillets and it was definitely a lighter color.

As it dried, though, the color began to match better and better.

 

[JAL3]

While cutting the BT, I realized that I would have to redo the shock cord. I hate trifolds but I saw no other option. I made one from some scrap paper and anchored it to some Kevlar thread. I then glued the mount in with white glue.

The neck will still need some cleaning because I apparently did not get all the dog barf out before starting.

 

[JAL3]

A little bit of sanding inside the front end of the BT and then everything fit back in. The rocket is a bit shorter now but still should perform fine.

 

[Micromeister]

John:
Glad to see your model wasn't damaged to badly and the fix looks great.

Generally if your going to use an adapter it's advisable to use them in models with motor retainer hooks or make sure you leave enought of the adaptor outside the aft end of the model for both internal and external taping.
Its become automatic for me, even with motor hook models to add a wrap of 1/4" masking tape just as a failsafe.
On models with the fins attached at the extreme end of the body tube like your, I add 1/4" strips between each fin and then wrap the overhang to the adaptor/motor. If you can't tape to the adaptor, wrap the extended part of the motor.
Over time I've learned to alter most of my minimum diameter model builds to allow about 3/16" -1/4" of body tube below the aft end of the fins. This takes all the fight out of adapting those BT-20 size models to 13mm motors or BT-50 models to 18mm adapters. Thus far it's helped prevent adaptor ejections.

 

[JAL3]

John:
Glad to see your model wasn't damaged to badly and the fix looks great.

Generally if your going to use an adapter it's advisable to use them in models with motor retainer hooks or make sure you leave enought of the adaptor outside the aft end of the model for both internal and external taping.
Its become automatic for me, even with motor hook models to add a wrap of 1/4" masking tape just as a failsafe.
On models with the fins attached at the extreme end of the body tube like your, I add 1/4" strips between each fin and then wrap the overhang to the adaptor/motor. If you can't tape to the adaptor, wrap the extended part of the motor.
Over time I've learned to alter most of my minimum diameter model builds to allow about 3/16" -1/4" of body tube below the aft end of the fins. This takes all the fight out of adapting those BT-20 size models to 13mm motors or BT-50 models to 18mm adapters. Thus far it's helped prevent adaptor ejections.

Thanks. I DO appreciate the info.