Estes vs Quest Engines

[RadioFlyer]

Up until now, I've been using various Estes engines for our flights because they happened to be available (A-8-3, B-6-4, C-6-5). However, I notice the Quest engines look similar and have the same ratings for about the same price.

I know they don't recommend using the Quest igniters with the Estes launch controller (which is what we have). That's because the power needed to cause the igniter to ignite is lower than what is needed by the Estes igniters. Could an Estes igniter be used in a Quest engine, or vice-versa if I ever got a Quest launch controller?

I'm curious about compatibility and if anyone prefers one engine manufacturer over the other and why. Is there any performance difference between the two? Any difference in reliability? Are some better than others in certain conditions? I'm just trying to get an idea of what my options are. Thanks in advance.

Bob

 

[KerryQuinn]

Bob-
The engines from Quest and Estes are fairly interchangeable - that's the whole idea between having a standard engine rating system. For the most part, a B-6-4 from either manufacturer will fly about the same in the same rocket.

There are differences between them - and you can get these details by looking at the measured thrust vs time curves (which are available many places in the internet including the nar.org website.) A commonly recognized difference is that the quest C-6-3 has a higher peak and longer burn time than an estes C-6-3(see attached). There are also some very small (but sometimes significant) dimensional differnces - the quest engines are slightly larger diameter - but they will still fit in the same engine tubes - just press in a little harder. The Quest engines also tend to get a bit hotter when they burn.

You mentioned one of the most important differences - the igniters are VERY different. Almost everyone strongly prefers the Quest igniters - they are very reliable, durable and less likely to short out - but they have a low ignition current as you describe. The Quest launcher WILL work with estes igniters. You can also launch quest engines using estes igniters (but why would you?)

Go ahead and purchase some quest engines and igniters and try them out.
Note that you can purchase bulk quest engines from the https://www.questaerospace.com/index.asp web page - and from time to time they offer some pretty good sales on that site - a good time to stock up.

-Kerry

 

[TheAviator]

Kerry mentioned that the Quest C6's burn longer than the Estes C6's. This also translates into a lower average thrust, the Quest motors have an average thrust of 3.5N, not 6N. They work well in lighter rockets or in clusters, but beware if you put them in a heavier rocket, as the sustaining thrust may not be enough to keep the rocket going up. If in doubt, use the short (3s) delay.

The Quest B6 and A6 do not have this problem; they can be used interchangably with the Estes B6 and A8 respectively.

 

[MarkII]

Estes igniters are extremely reliable, as are Quest's. The two have different designs and as you noted, different firing amps. Quest's launch controller was developed for their previous igniters, which had about the same amp draw as the Estes igniters have, so with a fresh battery it should have no trouble firing its competitor's igniter. In my experience the 9 volt battery in Quest's controller becomes drained substantially faster than the 4 x AA batteries in the Electron Beam controller when it is used to fire Estes-style (and older Quest) 2-3 amp igniters. Because the igniters that Quest now uses draw much less current, the battery in their controller should last longer if it is only used to fire their own product. Quest does sell an accessory that allows their controller to connect to one of those big square lantern batteries, which provides greatly enhanced endurance.

If you use an Estes igniter in a Quest motor, you will need to have some way to hold it in place. I don't know which, if any, of the 5 different Estes plugs will fit into Quest motors. If none of them do, then you'll have to use some other method, such as a strip of tape or a small ball of wadding to hold it in. Using an Estes igniter may be one way to safely fire their motors at some club launches. Our launch panel, for instance, will fire a Quest igniter during the continuity check prior to pressing the launch button. (We need to fix that.) Check with the RSO at the launch to find out if you can use Quest igniters with their system. Bring along a few Estes or previous generation Quest igniters (or some nichrome wire), just in case.

 

[BEC]

I often use Estes igniters in Quest motors so as to build up my stash of those marvelous Q2G2s for future use when I really want their special properties. A once-used (and not badly melted) Estes purple (B6/C6) plug works well enough in all Quest motors I have tried 'em in, including A6-4 (Chinese), A8-3 (German), B6-0 (German), B6-4 (both German and Chinese) and C6-5 (Chinese).

I don't like the Quest A6-4 very much as it seems to build thrust slowly so it's really only suitable for very light rockets (say half to 3/4 of an ounce unloaded). It seems it spends half of its energy before the rocket ever leaves the pad. The Bs are pretty comparable to Estes (but louder and with more than a full 4s delay on the B6-4). The long-burn Chinese Cs also need a light rocket but in the right combo they are very impressive.

The 4.6s burn odd-sized Quest D makes for really impressive flights as well - but since they are such an odd size there's really no Estes comparison.

 

[powderburner]

You can take the simple, trial-and-error approach, and just swap the motors and try a launch. This may or may not be successful.

If you have some nice model rockets that you don't want to crash, it could be a good idea to study the time-thrust curves shown at:
https://www.nar.org/SandT/NARenglist.shtml
Find the motors you want to compare and click to pull up the specifics. If any significant portion of the new (Quest) time-thrust curve falls below the previous (Estes) curve, that means you have less thrust, less acceleration, and worse performance.

To make sure the new motor will still work in your specific model rocket, you are just going to have to do the math. You can load things up in a sim (a basic version of rocsim is free online, as well as several others) and get pretty close.

Trying to do much less is basically just guessing.

 

[gpoehlein]

I don't like the Quest A6-4 very much as it seems to build thrust slowly so it's really only suitable for very light rockets (say half to 3/4 of an ounce unloaded). It seems it spends half of its energy before the rocket ever leaves the pad.

Maybe so, but the A6-4 is sure a lot of fun in my Astron Ranger (3x18mm cluster)! A lot of smoke and apogee is low enough that you can hear the distinct "pop - pop - pop" of the three ejection charges going off one after another!

 

[BEC]

Maybe so, but the A6-4 is sure a lot of fun in my Astron Ranger (3x18mm cluster)! A lot of smoke and apogee is low enough that you can hear the distinct "pop - pop - pop" of the three ejection charges going off one after another!

I have a Ranger clone in primer right now and am looking forward to exactly the same thing - since I have a 25-pack of QA6-4s on hand. Maybe there'll be a break or two in the weather and I can have it ready for our next club launch - second Saturday of November.

 

[hcmbanjo]

Kerry mentioned that the Quest C6's burn longer than the Estes C6's. This also translates into a lower average thrust, the Quest motors have an average thrust of 3.5N, not 6N. They work well in lighter rockets or in clusters, but beware if you put them in a heavier rocket, as the sustaining thrust may not be enough to keep the rocket going up. If in doubt, use the short (3s) delay.

The Quest B6 and A6 do not have this problem; they can be used interchangably with the Estes B6 and A8 respectively.

I agree!
I saw a Dr. Zooch Saturn V flown on a Quest C6-5, the C6-5 is a recommended engine for the kit.
The boost seemed fine, but at a low apogee it started to tailslide and landed fins first. Most of the delay was burning on the ground before the ejection went off. Not enough "oomph" after the initial spike.
Maybe this is why Quest only recommends their B6-4 for the MLAS.

I've just finished up a 25 bulk pack of B6-4s. No problems with those except they leave more soot on the tail end of the rocket. The interior tube walls are left with a little more grit too.

 

[BEC]

I've just finished up a 25 bulk pack of B6-4s. No problems with those except they leave more soot on the tail end of the rocket. The interior tube walls are left with a little more grit too.

Yeah, I've noticed that, too - saw it again yesterday when I flew one.

 

[eugenefl]

I recently flew an Estes Citation Patriot (BT60 dia, clone) on a Quest C6-5. It was slow and lazy off the pad, weathercocked into the breeze, and came within feet of hitting the ground. The ejection deployed a chute which served as a brief airbrake and essentially saved the model from impact. The rocket popped a fin that was well anchored to the tube and took some body tube spiral with it.

 

[Solomoriah]

What's really funny is that the Quest A6-4 is just about perfect in an Estes Alpha. The deployment velocity is almost zero; neither the Estes A8-3 nor A8-5 works as well.

 

[boomtube]

I use both Quest and Estes motors interchangeably and have used Quest booster motors in conjunction with Estes sustainers and vice-a-versa.

What I won’t do is mix the two brands in clusters. That would probably count as a “Bad Idea”.

What I will do is use the Quest Q2G2 igniters in all my cluster rockets.

 

[MarkII]

I use both Quest and Estes motors interchangeably and have used Quest booster motors in conjunction with Estes sustainers and vice-a-versa.

What I won’t do is mix the two brands in clusters. That would probably count as a “Bad Idea”.

What I will do is use the Quest Q2G2 igniters in all my cluster rockets.

Oh, I certainly would. I'd love to do a cluster that consisted of three Estes A10s evenly spaced around a central Quest D5.

 

[Solomoriah]

Ooh. Sounds like a heavy-lift arrangement. You'd want to be sure the D5 thrust "tail" is powerful enough to keep the rocket going after the A10s burn out. Kind of a balancing act... big enough but not too big.

 

[ScrapDaddy]

Kerry mentioned that the Quest C6's burn longer than the Estes C6's. This also translates into a lower average thrust, the Quest motors have an average thrust of 3.5N, not 6N. They work well in lighter rockets or in clusters, but beware if you put them in a heavier rocket, as the sustaining thrust may not be enough to keep the rocket going up. If in doubt, use the short (3s) delay.

The Quest B6 and A6 do not have this problem; they can be used interchangably with the Estes B6 and A8 respectively.

It should be noted however, that the quest motors have a higher initial spike, but a lower sustaining thrust.

 

[MarkII]

Ooh. Sounds like a heavy-lift arrangement. You'd want to be sure the D5 thrust "tail" is powerful enough to keep the rocket going after the A10s burn out. Kind of a balancing act... big enough but not too big.

That's why I would use the "mighty mite" A10s. Not for heavy lifting, but for a quick 0.82 sec. punt off the pad. The A10s would be tasked with getting the rocket going from a standing start so that it doesn't have to rely entirely on the D5 for that. After burn-out, their empty mass won't be much of a problem. At about 0.17 seconds after ignition, the combination of the 3xA10 + D5 would be putting out around 41-42 Newtons of thrust. The A10s' thrust will quickly drop off after that while the D5's thrust will continue to climb. At T+ 0.5 secs. the combination will still be putting out over 20 Newtons of thrust. At T+ 0.8 secs. it will be down to around 8 Newtons, but that won't be so bad. Remember that the D5 is barely larger than a standard 18mm motor. It will continue to put out about 3.3 Newtons of thrust for the next 3.7 seconds. In the right rocket, that would be one sweet thrust profile.

 

[SCE to AUX]

You can also launch quest engines using estes igniters (but why would you?)

I do it all the time because:

A.) I have a LOT of extra Estes igniters kicking around my range box.

and

B.) That way I can hoard the Quest igniters for clusters and firing HPR ejection charges.

 

[JAL3]

I do it all the time because:

A.) I have a LOT of extra Estes igniters kicking around my range box.

and

B.) That way I can hoard the Quest igniters for clusters and firing HPR ejection charges.

I do the same.

For what its worth, the Quest A6-4 is one of my favorites.

I also like the long burn Cs but have been burned by their lower thrust, even with a cluster of 7 of them. My BT70 Vulcan took off just fine but, after the initial spike, did not have enough oomph to keep things moving in the right direction. That would be up.

 

[Solomoriah]

What's funny is, the A6-4 is the perfect engine for the Estes Alpha. Neither the A8-3 nor the A8-5 have such perfect delays. I've simmed it in Rocksim (v8 demo a couple of years ago) and OpenRocket, and the Dv is lower with the A6-4 than with any A8 Estes engine. Also tested practically.

 

[Solomoriah]

i don't get it

Um... okay.

The A6-4 is a Quest engine, yet it's perfect for the iconic Estes rocket. Better than either Estes A8 engine.

See?

 

[hcmbanjo]

I agree about the Quest A6-4 being a great engine, especially for small fields.

The A6-4 seems to take a moment to build up steam before the rocket leaves the launcher.

And like you said, for 12" to 15" tall BT-50 based models, the four second delay fits better than an A8-3.

This morning I flew a Quest A6-4 in an Eric Truax Carded Scamp - a perfect flight.