Just got the new Estes Long Tom

[gpoehlein]

Picked up the new Estes Long Tom yesterday. As many know, it is part of their new Classics series and is a new version of a Centuri 2-stage model produced back in the 70s.

I was a little disappointed in comparing the new version to the instructions posted on Jimz - the balsa nose cone and transition are fine (the originals were plastic), but they changed two things that would have made it - in my opinion - a better kit.

The first is that they changed the two stage arrangement from the Centuri "Pass Port" vented system with a motor clip on the second stage to the typical "tape two motors together and friction fit them in" Estes method. Disappointing because I was wanting to use A10-0 motors with an adapter in the booster stage (since the A8-0 is not available and I have a bunch of OOP A10-0s in my inventory). This will be more difficult since there is limited surface area to "tape together" with an adapter. Not saying it can't be done, but I would have liked to play with the ported system.

The second is the elimination of the ejection baffle. I guess they left this out of the kit just because it would have made the kit a bit more expensive and they could cut this corner without detracting from the kit. And, unless you had those old instructions, you wouldn't know what you were missing.

Bottom line on first opening (I'll build it soon), I give this one an A-. It looks like a really nice kit with easy to read instructions (interesting note, Estes has stopped numbering the steps in their instruction sheets - not really a problem, but a newby MIGHT be confused about the sequence the rocket should be assembled in, though not really likely). The two omissions are not enough to be a problem (and are easily added from the spare parts box) but enough to me to drop it from an A+ to A-. ;)

[BobH48]

Greg,

I've knocked the nozzles out of expended motors and glued A10-0T's into them to make 18mm "A" boosters rather than use an adapter.

You will need to ream the inside of the motor casing to make them fit.

You can also use the dummy engine casing that comes with various Semroc kits for installing engine blocks. They are much closer to the correct size and some sandpaper on a dowel quickly opens them up to the correct size.

On a side note, about 40% of the A10-0T boosters I have used in the NAR OOP motor testing program have not worked as they should. Most of the failures are when the booster burns right through and the model stages on the rod or slightly after leaving the rod.

A couple just blew the booster apart without even moving but still managed to ignite the sustainer.

Most of the failures were from packs with date code "6 A 6" but not every one failed.. Fortunately, I only have one more pack with that date code.

[shreadvector]

Quest motors made in Germany are PERFECT for 13mm motor adapters.


Greg,

I've knocked the nozzles out of expended motors and glued A10-0T's into them to make 18mm "A" boosters rather than use an adapter.

You will need to ream the inside of the motor casing to make them fit.

You can also use the dummy engine casing that comes with various Semroc kits for installing engine blocks. They are much closer to the correct size and some sandpaper on a dowel quickly opens them up to the correct size.

On a side note, about 40% of the A10-0T boosters I have used in the NAR OOP motor testing program have not worked as they should. Most of the failures are when the booster burns right through and the model stages on the rod or slightly after leaving the rod.

A couple just blew the booster apart without even moving but still managed to ignite the sustainer.

Most of the failures were from packs with date code "6 A 6" but not every one failed.. Fortunately, I only have one more pack with that date code.

[MysticalRockets]

The second is the elimination of the ejection baffle. I guess they left this out of the kit just because it would have made the kit a bit more expensive and they could cut this corner without detracting from the kit. And, unless you had those old instructions, you wouldn't know what you were missing.




I know exactly WHY they left it out. The sell alot of wadding, and charge a fortune for it. That's why.

[rocketron1948]

Greg,

I built a clone of the Log Tom using parts and decals fro Semroc. The pass port staging problem can be solved by using the following parts from Semroc: St-730, ST-740 and HTC 7B.

Rocketron1948

[Brent]

I wonder if one of the reasons behind getting away from plastic was the X-15 incident.

[shreadvector]

I wonder if one of the reasons behind getting away from plastic was the X-15 incident.


No. it was simply the new federal toy testing laws. Extensive explanation was provided by Estes people in-person, direct from them personally, on YORF.

[ghrocketman]

Specifically due to the lack of baffle, and the lack of Passport staging on the re-release of the Long Tom I would rate the kit a B- to B.
If the missing/incorrect features were corrected, I'd give it a B+ to A-

[Captain Ron]

Has anyone tried using 24mm engine mounts instead of the 18mm?

[plano-doug]

On a side note, about 40% of the A10-0T boosters I have used in the NAR OOP motor testing program have not worked as they should. Most of the failures are when the booster burns right through and the model stages on the rod or slightly after leaving the rod.

A couple just blew the booster apart without even moving but still managed to ignite the sustainer.

Most of the failures were from packs with date code "6 A 6" but not every one failed.. Fortunately, I only have one more pack with that date code.Hi, Bob,

I've burned a bunch of A10-0T's under the OOP program as well as at indy launches, and haven't had a single failure. I'm pretty sure that includes several 6A6 branded parts. So I suspect you have some motors that were poorly stored (perhaps prior to you acquiring them). Your failure descriptions sound like case debonding as caused by temperature cycling (rather than being manufacturing related failures).

Doug

.

[BobH48]

Hi, Bob,

I've burned a bunch of A10-0T's under the OOP program as well as at indy launches, and haven't had a single failure. I'm pretty sure that includes several 6A6 branded parts. So I suspect you have some motors that were poorly stored (perhaps prior to you acquiring them). Your failure descriptions sound like case debonding as caused by temperature cycling (rather than being manufacturing related failures).

Doug

.Hi Doug,

That's exactly what I've suspected. Bad storage. The A10-0T boosters that weren't that date code have worked just fine.

I got 10 packs of them a few years back from a couple different sources and when I was listing them for the OOP program, I noticed that 3 of the packs had the same A6A date code. I don't know for sure, but suspect that I got all those at the same time from the same source.

At the time I posted my findings, I had used 2 pack with A6A date code with mostly failures and almost 3 packs without that date code that did not fail which is where I came up with the 40% number.

I don't think that there is a problem with A10-0T's as a product or I would have expected high failure rates with A10-3T's also.

With them being recertified, I can now fly A10-0T in an adapter staged to a 1/2A5-4S which I couldn't do before because of the "one OOP motor per flight" rule.

[plano-doug]

With them being recertified, I can now fly A10-0T in an adapter staged to a 1/2A5-4S which I couldn't do before because of the "one OOP motor per flight" rule.Oh, you read the one-OOP-motor-per-flight fine print, too :D I have several birds where I could have, if allowed, flown three or more OOP motors on the same flight :)

So, at least for A10-0T's, I'm glad they're recertified - I can now fly some complex rockets at club launches where having the extra folks is helpful in getting all the pieces back ;)

Doug

.

[KurtH]

Has anyone tried using 24mm engine mounts instead of the 18mm?


I did ... I built the a booster with 24mm mount and tried c11-0 to
B6-0, but the upper stage failed to ignite. I think it was because I tried to tape the c11-0 to the b6-6. Can not try it again because I lost the Long tom :(

On the last flight of the long tom, I had some thing on my fingers, probably petroleum jell from building RMS motors, so the scoth tape would not stick, so I decided not to tape the motors togther and they still lit.