Q-Jet motors won’t fit any of my rockets

[DankMemes]

Ok, I’ve got to missing something here but in just got in a couple of two packs one of the A3 and B4 q-jets to mess around with in some of my smaller rockets.

However upon trying to insert the engines it became clear that they would never fit as the housing is roughly the same diameter as the OD of a standard 18 motor mount tube, and I tried literally all of the 30 rockets I have in my flying LPR fleet... including some of the rtf and e2x kits with the screw lock mounts

Thought it might be the label, but I could even get the motors in that far.

Am I missing something?

 

[BEC]

Yes.

https://www.rocketryforum.com/threads/quest-q-jets.142027/

Maybe we’ll see (and be able to buy) the revised motors at NARAM next week.

 

[DankMemes]

Hopefully... I didn’t see any reference to the size issue in that thread. But I’ve got four motors I’m scratching my head to find a use for

 

[DankMemes]

Derp... skipped page 2 apparently there was a dude that wrote that they fit a quest tube just fine which ha a slightly larger ID... hmm maybe I’ll dig one if quest rockets out of mothballs

 

[BEC]

I found that if I peeled the label off and cleaned up the sticky residue with Goo Gone then I could get them in some of my models with BT-20 motor tubes. The fit is easier in models with ST-7 motor tubes (old Centuri or Semroc repos of Centuri designs...and some Semroc originals). I just marked the motor designation on them with a silver Sharpie after I removed the labels, so I knew what I had.

Much more discussion in a big thread on YORF. Start on Page 17: https://www.oldrocketforum.com/showthread.php?t=17128&page=17&pp=10

 

[DankMemes]

Wow, ok glad to know I’m not the only one... I have left over parts from some kit bashing to cobble together an alpha III, I probably have some st-7 tube left somewhere around here, guess I’ll piece that together to burn these motors in..

Was a little disappointed on the flight line today when I tried loading these in my alpha VI would have been cool to see that little model puffing black smoke...

 

[Zeus-cat]

This is a well known issue. Why they didn't make these fit Estes BT-20 tubes is beyond me.

 

[kuririn]

Ok, I’ve got to missing something here but in just got in a couple of two packs one of the A3 and B4 q-jets to mess around with in some of my smaller rockets.

However upon trying to insert the engines it became clear that they would never fit as the housing is roughly the same diameter as the OD of a standard 18 motor mount tube, and I tried literally all of the 30 rockets I have in my flying LPR fleet... including some of the rtf and e2x kits with the screw lock mounts

Thought it might be the label, but I could even get the motors in that far.

Am I missing something?

Dank,

You should contact Quest customer service (contact info is on their website) and tell them of your issues. I was offered free replacement Q-Jets with the revisions to correct the deficiencies when they become available. At least they back up and correct their mistakes.

 

[Arsenal78]

This is a well known issue. Why they didn't make these fit Estes BT-20 tubes is beyond me.

It would've made a lot more sense for them to size it to a BT-20 as Estes is the leading supplier of low power stuff. Quest is around but no one is going to go buy a Quest 18mm tube for a rocket. Their first thought is Estes.

 

[DankMemes]

Dank,

You should contact Quest customer service (contact info is on their website) and tell them of your issues. I was offered free replacement Q-Jets with the revisions to correct the deficiencies when they become available. At least they back up and correct their mistakes.

Thanks for the tip, definitely worth the a brief phone call or email...

 

[DankMemes]

interestingly enough the yet to be release c-12 and d-16 motors are spec to a smaller diameter:

https://www.questaerospace.com/2-Pack_D16-4_Q-Jet_Model_Rocket_Motor/p4193205_18980165.aspx

.698 '' vs the .703'' of the b4 and a3 motors

 

[neil_w]

Yeah well they adjusted them after feedback from the As and Bs. The alternative would be that no one would buy them...

 

[DankMemes]

Wow, I must say I'm impressed how this story ends, and to the level of service I received.

So on Monday I emailed [email protected], and just an hour ago received a personal response from none other then Charles Savoie and Karl Baumann, GM and VP R&D of Aerotech, talk about the personal touch.

With that they explained the story behind the motors and offer to send me replacements with the corrected diameter, no questions asked. In all honesty I wasn't expecting or requesting that since I have some beater rockets I could cram these into, just wanted to give them some frank feedback.

They seem like good guys out there, and wish them well and hoping this issue gets corrected soon, the d16 an new C motors will definitely fill some holes in my lineup.

 

[BBowmaster]

So, just to be clear, Q-jet motors from here on out WILL fit a standard Estes BT-20 tube?

 

[DankMemes]

Yet to be actually tried but the specs for the c and d’s on quest aerospace website shows that the diameter will fit... I also have confirmation from Karl that a new batch is coming that will fit with labels, just didn’t specify when... so stay tuned...

 

[BEC]

That is what Karl told me as well.....

Some cautions/caveats: first, if you were heavy handed with glue on centering rings and the BT-20 is squeezed any, or if it’s dirty with ejection residue and such, they may still be too tight.

Second, if you have a motor hook, especially the Estes type with the finger tabs (as they’ve been for a long time) you may or may not be able to get the ejection charge container past the hook even if you are careful to orient the motor so that a flat of the hex shape is opposite the hook....though that end of the Q-Jets is also supposed to be tweaked a bit in subsequent batches. Being able to cope with this on a new build is easy - just take 1/16 of an inch or so off the upper end of the hook with a Dremel cut-off wheel. But for existing models it remains to be seen if the proposed minor tweaks will be sufficient.

 

[DankMemes]

Also this is my own to cents I’d recommend checking with your vendor of choice before buying to see what they have in stock

 

[DankMemes]

For the oversized motors I do have looks like they’ll slide into bt-20 centering rings, so I’m planning on building a 3FNC burner rocket to test them out in just skip the motor tube and lay down 3 centering rings and friction fit the motors in there with a tape thrust ring on the motors.

 

[DankMemes]

UPDATE: received an unexpected packaged today from aerotech/quest, surprised as I wasn’t expecting my shipment of c & d q jets in...

Lo and behold, it’s the update qjets ( A&B) not sure what to expect I tried them in my rockets and I was pleased to see they do fit in all my Estes rockets, even with aftermath engine blocks (cut from spent motors), and with the engine labels on!!!

Attached you’ll see the motors in a random sampling of the different kinds of mounts across multiple decades. All drop right in, sometimes you might need to rotate the engine a bit to align right if the for end of the engine hook has a longer finger but didn’t have any trouble getting them in



Looking forward to flying these tomorrow if the wind cooperates...

Thanks Chuck and Karl on your great customer service and can’t wait to try out those c&d motors

 

[BEC]

That sounds great. Hopefully I'll be getting a care package from Karl soon myself.

 

[DankMemes]

That sounds great. Hopefully I'll be getting a care package from Karl soon myself.

Should be soon these motors are hot of the presses to mfr. date is 8/23