Estes Sprint XL #7224 Build, Part 3, Tail Cone Fit

First up you'll have to widen the low end hole.
200 grit was wrapped around an 18mm casing. Constantly check the fit of the BT-50 engine mount tube.







The engine hook slot was widened with a small diamond coated file.

Even though the slot was wide enough at the back, the hook was still getting caught up inside. The interior walls had to be hit with a knife.







Here's the final fit with the mount slid in place. The BT-50 tube is flush with the end of the tail cone.
I did remove the finger tab and flipped the hook over.
The fins don't sweep back on this one so the engine hook seems longer than it should be.

Clearing a Glue Nozzle - TIP

Here's one way to clear dried glue from a nozzle tip.

Cut the end of a Q-tip stick off at an angle. (I use a LOT of Q-tips when I make rockets.)
Turn the nozzle like you are opening it up for gluing. Pull the nozzle off the bottle by pulling hard straight up.

Push the dried glue plug out from the bottom. The angled cut end should go through the small nozzle hole cutting through the dried glue.

Estes Sprint XL #7224 Build, Part 2, Tail Cone

You could cut through the nose and tail cone with a razor saw but I used my break-off blade knife.
Repeated scoring and the plastic was separated.







The tail cone needs the most work.
When first broken off the slot for the engine hook is very narrow.

GOTCHA: Trust me, do a dry fit (no glue yet) of the engine mount and fit it to the tail cone. If I glued the centering rings at the positions shown in the instructions my lower ring would have been off by 1/16".

Estes Sprint XL #7224 Build, Part 1, Parts

I've wanted to build this one for a while. I picked up two in the Estes clearance sale.
I had an Astron Sprint in the early 1970s. It was considered high tech and high performance back then.

The parts look good, no problems yet.
Only one set of decals is included for the simpler looking scheme.
Two pats of nose weight clay together total .50 oz.
The engine mount tube is a heavy wall BT-50.
The nose cone and tail cone are blow molded.

Estes Sprint XL Background

The first K-49, BT-50 based Estes Sprint was introduced in 1970. It was advertised as "The First True Competition Model".
To see the catalog page, CLICK HERE
Very few models had boat tails back then. The Sprint sported a low drag parabolic nose cone and fin shape. It used 18mm engines, streamer recovery and came with two different decal motifs.
On the original the boat tail was formed from card stock. There was no engine hook, the engine was friction fitted with masking tape.
The old Sprint stood 13.8" tall.



The newer Sprint XL is an upscale model built around a BT-60 and uses 24mm engines.
"In memory of Mike Dorffler (1946-2010), longtime Estes Model Rocket Designer." Mike Dorffler designed other models including the Estes Cineroc.
The Sprint XL is 22.8" tall.

The Sprint XL build starts tomorrow!

Estes Galactic Taxi #1914 Finished

This was fun - except for the decals!
The first print of the online scan couldn't be used. The print art was fuzzy.
On the second print, cold temperatures prevented the clear coats from going on smooth. On a few of the decals, small specs of the print dissolved in the soak water. If they fit, I'll usually print two full sets and some extras on one sheet. I ended up using the extra decals to get two finished models.
The added black in the decals helps define the final look.
The picture on the lower left was taken before I added the orange decals to the bottom of the wing.
With the card stock wing fairings the model profile is out of the ordinary.
This should be a good small field flyer using an A8-3 or A6-4.

Mercury Little Joe Auction Almost Over

The Mercury Little Joe I EBAY Auction
finishes up Tuesday, Tonight!

CLICK HERE

This model was built from plans from the 1973 Enerjet News.
It uses the Centuri Mercury Capsule now in the Mercury Redstone kit from Estes.
A clean build with custom decals and extra upgrades.

Stop by make a bid and support the blog!