Quest v. Estes Engines in LPRs

[Tom Flint]

I've flown all the Q-jets from the A3 to the E26, and I like them overall for something different to fly. I like the A3 and B4 better than their Estes counterparts. The A3 burns longer than the Estes A8 and makes for a more exciting flight. The B4 just seems more interesting than the black powder version. I wish the C's and D's burned slower but I like the D's for my models with an 18mm motor mount that just need more power than a C. And the E26 is great in my Big Red Max. I have had some of the larger blackjack motors shed a tiny piece of nozzle clay which causes the rocket to turn a little bit during boost, but it has not caused any catastophes, and I think it has been fixed on newer batches of motors as I've only experienced it with earlier production motors.

 

[user 38430]

The short burn time is why I have little interest in Quest motors, they seem more like Gun shots than rockets. I'm not thrilled about using plastic casings instead of paper for environmental reasons as well.

 

[Antares JS]

I didn't think of that. How do you ignite these "roman candle" Q-Jet engines? Do you have to waste a good igniter to do so? Out of curiosity, why can't you just soak these composite engines in water to destroy them? They still work when wet or something?

Since no one seems to have answered this question, just going to confirm for you that APCP is not water-soluble and will burn underwater.

The only Q-jets I really like are the D16's and the B6's. The B6-4's outperform the Estes B6-4 in every way, and the D16 is great for heavier models with 18mm motor mounts. C18's and D20's are too punchy for my taste. A3's, B4's, and C12's are fine but don't interest me that much.

I have a few of the 24mm Q-jets waiting in the wings, just haven't gotten around to trying them out yet.

 

[AeroTech]

Most of the Q-Jet issues discussed here have been fixed in current motor production. As always, if you have any failures please contact Karl at the email address in my sig.

 

[AeroTech]

Since no one seems to have answered this question, just going to confirm for you that APCP is not water-soluble and will burn underwater.

The only Q-jets I really like are the D16's and the B6's. The B6-4's outperform the Estes B6-4 in every way, and the D16 is great for heavier models with 18mm motor mounts. C18's and D20's are too punchy for my taste. A3's, B4's, and C12's are fine but don't interest me that much.

I have a few of the 24mm Q-jets waiting in the wings, just haven't gotten around to trying them out yet.

I think you will really like the 24mm Q-Jets.

 

[ZoomieG]

Hey mh-

There are a lot of good answers to your technical questions in this thread, but I'd like to point out that the whole discussion is based on a false assumption.

I'm beginning to see why the Q-Jets are so cheap...

Q-Jets are not cheap. I think you'll find that across most vendors, they either match or exceed Black Powder cost per similar powered motors.

For example, there's a 12 pack of Q-Jet A3-4s for less than $23. So now I'm reconsidering whether I should focus many of my rocket builds around the 13mm engine. Based on my research, here are the benefits of the Q-Jet A3-4s over an Estes BP rough quivalent, like the A8-3. These include:

- Price

Did you actually put this 12 pack in your cart and go to check-out? I am guessing not, because if you had, you'd find that 12 pack would set you back almost $43, not $23.

I am not trashing on Belleville here; in fact I've ordered from them at least twice. However, they have a minimum shipping price of $17.99. Past two to three items, that price goes up, and can go way up. For that particular item, you can order two at that shipping cost. If you order a third, shipping bumps to over $30.

Bottom line: when comparing Belleville prices, you have to bump theirs to include their high shipping costs.

The best price per motor currently available (that I've found) is the 24 pack of A8-3s from Hobby Lobby. They charge $39.99 for this, and regularly have free shipping for orders over $50 on their site. That's $1.67 per motor.
https://www.hobbylobby.com/Crafts-H...ing/Rockets/A8-3-Model-Rocket-Engines/p/34504

 

[mh9162013]

I am not trashing on Belleville here; in fact I've ordered from them at least twice. However, they have a minimum shipping price of $17.99. Past two to three items, that price goes up, and can go way up. For that particular item, you can order two at that shipping cost. If you order a third, shipping bumps to over $30.

TIL, thanks!

 

[NateB]

I think the black powder is rendered non-flammable too, although I’m not certain of this.

Wet BP won't burn and damp BP will only sputter. If it is allowed to dry out again, it will burn. In fact, BP type compositions for rocket motors is prepared wet after milling and dried out into granules before pressing into a motor.

I'm practice, the amount of BP in A-F motors is not a big factor when you dispose of a motor. Soaking a bad motor and crumbling the wet BP in the dirt is just fine. BP is made from things that are good for plants.

 

[smstachwick]

Wet BP won't burn and damp BP will only sputter. If it is allowed to dry out again, it will burn. In fact, BP type compositions for rocket motors is prepared wet after milling and dried out into granules before pressing into a motor.

I'm practice, the amount of BP in A-F motors is not a big factor when you dispose of a motor. Soaking a bad motor and crumbling the wet BP in the dirt is just fine. BP is made from things that are good for plants.

Maybe if I ever have to do that, I’ll put it on my dad’s strawberries.

Rocketberries, anyone?

 

[brrrett2]

Watch this video from Ronz Rocketz. He was experiencing the same issues I am but I think he is having better luck than I am. One of his was a burn through and the next was a super long delay.

Nice flight! Yikes, your flying site is small. Good video though. What was that camera you used?

 

[BEC]

Gary (@AeroTech) is of course correct that the issues we've been discussing have generally been fixed in current production of the 18mm Q-Jets. But there are still a bunch of motors "in the pipeline."

As I suggested before, I'm pretty sure that "$23" bulk pack of A3-4FJs probably dates back to the early slightly too large diameter production. Hence the price. The current price for a 12-pack of A3-4FJs is $42 and last time I went looking for bulk packs (though for C12s) it was next to impossible to find significant discounts, especially after shipping was accounted for. As a result I wound up ordering my last two 25-packs of C12-6FJs direct from Quest/Aerotech. That $23 price is an anomaly, not a generally available price.

@Antares JS I'm glad to hear that you've gotten good results from B6Ws. I look forward to flying more of the current production ones myself. The first production ones were...well, underwhelming, after flying a couple of pre-production motors at NSL last year. Remember I fly an altimeter in just about every model I fly, so I have comparative data across dozens, and in a couple of cases, hundreds of flights of two models in particular.

And yes, I've been in touch with Karl about that. He's a busy fellow.

Added: I've yet to see the Q-piks in person. I look forward to them as the shrink tube initiator retention method works sometimes but sometimes not so much. I've fallen back on the ancient practice of using little balls of wadding to do this job sometimes.

 

[Paul Howard]

I recently launched my heavy modified Chuter-2 (a night launcher with LED's, battery, payload section, ejection baffle, hardwood leading and trailing edges) with :
-Quest Composite B6-4's(? maybe 6 second delay?) - and they seemed comparable to Estes Black powder but flew a little erratically and I wasn't sure if it was the turbulent breeze or the motors. Eyeballing the flight, the altitude seemed about equal, but, next..........

-Quest Composite C12-6's !!!!!! That rocket went up SOOOO fast it was hard to track from the 20 ft distance to my launch controller and I think it went noticeably higher than with Estes Black powder C6-5's. This rocket has very good airfoils sanded in and a BT-50 diameter so it's pretty aero-clean and though it's not a heavy pig, it is heavier than it would have been "stock" per plans which may have helped gain altitude with the more powerful engine.

- This effect happens in archery with arrow distance shooting as well, Aim a 50 lb bow 45 degrees up and pull the standard 28" and a 700 grain arrow will fly slower-off-the-bow but farther than a 300 grain arrow due to penetration of mass overcoming drag (which slows the lighter arrow sooner and more substantially). Of course, there are "points of no return" then loss of performance with adding too much weight.

As far as "CATO" and other Motor Failures go: I launched a LOT more as a kid in the 70's and I just don't remember Estes motor problems back then, now I recently had an A10-3T "Roman Candle" my Mini-Fat-Boy and a D12-3 non-ejection "lawn-dart" my V-2, and it seems like there are a lot of failures shown on group-launch and individual-launch videos in the past year or more.

Those were the only 2 packs of Quest motors = 4 Total that I have used out of curiosity. So far, no problems but that only 4 launches with 4 Quest motors.

Just my 2 Cents.

 

[BEC]

-Quest Composite C12-6's !!!!!! That rocket went up SOOOO fast it was hard to track from the 20 ft distance to my launch controller and I think it went noticeably higher than with Estes Black powder C6-5's.

This has been my experience and I have altimeter data to back it up. Easily 20% or more greater altitude and if the model is heavy (M.A.V, 1/200 Saturn V) nearly double.

My most flown model, the Nova Payloader, is consistently a 650 ±50 feet flyer on an Estes C6 and is 900 feet ±50 on a Q-Jet C12FJ.

 

[smstachwick]

This has been my experience and I have altimeter data to back it up. Easily 20% or more greater altitude and if the model is heavy (M.A.V, 1/200 Saturn V) nearly double.

My most flown model, the Nova Payloader, is consistently a 650 ±50 feet flyer on an Estes C6 and is 900 feet ±50 on a Q-Jet C12FJ.

That’s interesting. For rockets that are heavier than optimum weight for their aerodynamic properties, is it possible that increasing thrust to achieve greater burnout speed will increase altitude? Air resistance won’t be as much of a factor with a more massive rocket, meaning one that has more inertia, that can better shove its way through. Based on your observations and similar ones I made with a fiberglass Wildman Darkstar Jr. in OpenRocket, it could be. Maybe it’s possible to optimize thrust to a rocket the same way it’s possible to optimize weight.

 

[lakeroadster]

That’s interesting. For rockets that are heavier than optimum weight for their aerodynamic properties, is it possible that increasing thrust to achieve greater burnout speed will increase altitude? Air resistance won’t be as much of a factor with a more massive rocket, meaning one that has more inertia, that can better shove its way through. Based on your observations and similar ones I made with a fiberglass Wildman Darkstar Jr. in OpenRocket, it could be. Maybe it’s possible to optimize thrust to a rocket the same way it’s possible to optimize weight.

If you want hard data to review, a simulation program will answer all these ^^^ questions. Then you can optimize which motor is best for each rocket, based on the parameters of the site you'll be launching at.

YMMV, but for some of my obese non-aero oddrocs, the only motors (*) that make them flight worthy, are composite motors.

*I've spent too much time designing and building my rockets to use cato prone Estes E motors

 

[prfesser]

Since no one seems to have answered this question, just going to confirm for you that APCP is not water-soluble and will burn underwater.

Technically, the AP oxidizer in APCP is water-soluble, but the binder is a synthetic rubber that's more or less waterproof. Soaking an APCP motor in water will ruin it; the surface AP will dissolve and paper casting tubes will swell. However, APCP below the surface can still be ignited and (depending on the size of the propellant chunk and on its burn properties) will probably continue to burn even if dropped into a bucket of water.

Hence the proper method for disposing of an APCP motor: burn the propellant with appropriate safety precautions.

The oxidizer in BP is extremely water-soluble, and commercial BP motors don't contain a binder, so soaking in water dissolves three-fourths of the material in the BP. The remainder---charcoal and sulfur--is pretty much innocuous.

Best,
Terry