An 18mm motor will just fit into a cleared-out 24mm Estes motor casing, and this is done all the time to create 18-to-24mm motor adapters. For the 20mm Quest motors to fit, the 24mm casing would need a millimeter of wall thickness reamed out of the inside diameter (enlarging the ID by 2mm), which could be a tedious task (very tedious if done by hand). It would be easier and quicker to construct a motor mount adapter out of the two tubes that I described previously. You are going to need to order these motors online anyway, so while you are at it, just shoot an order out to Semroc for some Series 085 and some BT-40 tubes too. It's just small-diameter paper tubing - the price won't break anyone. You'll only need to construct one or maybe two adapters from the tubing, which you will then be able to reuse indefinitely.

MarkII

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SAM # 0011

An 18mm motor can be forced into a used D12 since some of the inner layers are burned away. It's hard to cram an 18mm motor into a C11 motor.

It's possible that enough of the action-packed area just above the nozzle of an E9 is burned away to allow it's use as a 20mm motor adapter. I'll have to look around the garage for a spent casing sometime over the weekend...

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-Fred Shecter NAR 20117 (L2)
Southern California Rocket Association, NAR Section 430

An 18mm motor is still a snug fit in the upper end of a spent E9, just not as tight as it is in a spent D12. (I checked it a couple of minutes ago.) The spent E9 does show potential as a 20/24 adapter (better than a spent D12) but the ID would still need to be enlarged a bit. It's definitely worth investigating. Tragically, I don't have any Quest D5s on hand to do so right now, though.

You could probably do the enlargement with a power drill and a 3/4" sanding drum, with the spent E9 immobilized somehow.

MarkII

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SAM # 0011

You can peel the inside of D12/C11/E9 motor casing to make it fit. I made adapters for 21mm FSI motors that way, back in the day.

Here's an old FSI 21mm D18-4 in a D12-3 adapter.

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I love sanding.

Hi Phred, different subject than thread and thats "Goony Birds." Built a scratch "Bluebird Zero" then "Goonied it." Built two fin assemblies. One with a 29 MM and the other with 3 engine clustered 29mm's. Both fin assemblies worked great! Especially the 3 engine cluster last summer. However, I mounted the coupler in main body of rocket and now a very tight fit after 1st flight. Would love to launch again but, afraid of "failed" separation. Did use "anti-zipper" design and tubular nylon. Any ideas on fixing this joint?

Sounds like the ejection dirtied up the separation joint, or possibly it might have swelled if it landed on moist grass. Sand it down a little to clean it up and put a little dry lube on it. If it were a dark rocket, graphite would do wonders, but it will get all over the white of the BBZ. Baby powder isn't really a lube, but it will help cut the friction and it won't make a mess.

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I love sanding.

I received my Quest order today.

D5-4s & D5-6s in the box.

I'll be flying some of these motors tomorrow/Sunday.

Bob

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Got mine today. D5-0, D5-4, D5-6 a few Chinese C6-5's, and (don't tell MM) some MicroMaxx stuff.

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I love sanding.

I received my order today too. Since it contained motors, I wasn't expecting to see it until around mid-March. 6 D5-4s, 6 D5-6s and a Micromaxx launch set (finally). Now I won't need to drag out my 12v battery and my Aerotech controller just to launch MMX. And now I have a new range box, too; my order was packed in a repurposed Vortex Launch Set box! (Thanks, Quest!)

And another 2010 catalog! (Now I have two! )

(Hmmm. Lots of useful information on the outside of that box. You know, that Vortex Launch Set doesn't look like it would be a bad deal for a beginner... Good sized rocket... )

MarkII

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SAM # 0011

Mine showed up Thursday. I built a FSI Penetrator clone earlier in the week, but accidentally used a SEMROC ST-8 tube instead of the ST-8F. I'll have to head over to storage later in the week and see if I can find a more Penetrator-looking nose cone that will fit. The photo shows a original FSI D4, along with the Quest D5 and a FSI D18.

S.

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