Aero tech substitute for estes

[KILTED COWBOY]

Have an Estes Saturn V with a Boyce 5 motor cluster fin can.
Boyce is recommendations are an Aerotech E15-4 for center motor and
4 Estes B6-0 for the 4 outboard motors.
Never have done a 5 motor cluster before.
Do y’all think that it would be better to do all Aerotech motors?
If so what would be a good substitute for the Estes B6-0
Not sure if the Aerotech and the Estes would ignite at the same time using different igniters.
What do you experts think?

 

[kuririn]

Aerotech doesn't make booster composite motors, although you could leave out the ejection charge in the motors.
So I would stay with the Boyce recommendation.
Also the AT 18mm motors are D impulse, pretty punchy. A Quest Q-Jet B would be less punchy, but again the ejection charge would have to be removed or the design of the rocket modified to vent the ejection gasses.
Hoping that the central motor lights and doesn't misfire or chuff. Else it would go up and come down without chute deployment.
Sometimes composites take a little longer to ignite than black powder.

 

[dpower]

Have an Estes Saturn V with a Boyce 5 motor cluster fin can.
Boyce is recommendations are an Aerotech E15-4 for center motor and
4 Estes B6-0 for the 4 outboard motors.
Never have done a 5 motor cluster before.
Do y’all think that it would be better to do all Aerotech motors?
If so what would be a good substitute for the Estes B6-0
Not sure if the Aerotech and the Estes would ignite at the same time using different igniters.
What do you experts think?

I would *not* recommend clustering the E15 with BP - Aerotech White Lightning motors can take quite a while to ignite, often chuff, and are almost always much slower than BP. I've seen multiple attempts at clustering White-Lightning, and none have lit all motors. I've clustered CTI 24mm motors a few times with BP, they work very well - both the E22 and the E31 light just as fast as BP, though have less total impulse than the E15. How heavy do you expect it to be? I fly a modified Estes SV on a D12 + 4x C6 motors for great flights, around 450' - it weighs 19.4 oz w/o motors. When I want a bit of extra thrust, I substitute a couple C12/D16 Q-Jets in the outboards. Q-Jets cluster well by themselves, or in combination with BP motors. I'd recommend extending 18mm motor tubes all the way up, so you have redundant ejection charges, and don't need to kick the boosters.

 

[kuririn]

How about E12-4 in the core and B6-0s in the boosters? All black powder, KISS.
Don't know how you feel about the "reputation" of Estes E motors. I think the E9 was much worse than the E12.
In lieu of a Rocksim or OR file, maybe you can float that by Boyce for comment.

 

[burkefj]

Aerotech e15s haven't existed for a while, only E20 and E30, I would not trust an Estes e12 to boost that much mass if the side motors didn't light.

 

[kuririn]

The question is how much added weight is the Boyce fin can (and added nose ballast) over a stock build, and can 4 extra B motors handle that weight difference, plus their own weight?
Cuz an E12 alone on a stock build is the minimum recommended motor.
Plus what is the safety margin, i.e. what if one B doesn't ignite? How about two, etc.
With the right ignitors and power source I would feel comfortable in being able to light all five.
I've done 7 motors back to back, on a Hydra 7 and a Cluster Duck.

 

[KILTED COWBOY]

My rocket is weighing in at just a tad over 20oz without the motors.
Will need to weigh it with the five motors at some point.

 

[SDramstad]

Has anyone used a flash pan thats ignited by the central composite motor to light black powder outboards? That way if the main doesnt light then neither do the outboards.

 

[Steve Shannon]

Has anyone used a flash pan thats ignited by the central composite motor to light black powder outboards? That way if the main doesnt light then neither do the outboards.

I suspect that the hot gasses that exit a motor when the igniter is lit would light the powder in the flash pan even if the composite motor doesn’t light.

 

[heada]

I have done a 5 motor cluster with APCP in the center and BP in the outer 4. I used a "fast paper fuse" that burns at 0.1s/ft to 0.4s/ft, with a section going into the nozzle of the BP motors and held under the APCP motor. When the APCP ignites, it ignites the fast paper fuse which ignites the BP motors. The fuse will work going from APCP to BP but it will not work going from BP to APCP because it wont ignite the APCP. I bend one end over and put that into the BP motor and use the standard Estes plug to hold it in place. The other end is bent 90 degrees and gathered together with some cotton kite string and held under the nozzle of the APCP motor, several inches below to avoid being ignited by a chuff.

https://www.skylighter.com/collections/firework-fuse/products/quick-fuse-white-gn1207

It isn't restricted except for being over 18 years old and a hazmat item. At $15 for a 20 foot length, it should last you a dozen launches or so. Don't use it for anything else because it burns FAST, like REALLY FAST.

 

[KILTED COWBOY]

Thanks for all the advice, still not sure what I am going to try.
I have 7 months of hard work into this build, and for a LP rocket a bit of money.
Still do not want it for just a display model, I like to fly my rockets at least once.
If it does CATO it would be epic. I guess thaen it will be time for some whisky to drown my sorry.
Then off to rebuild it.

 

[kuririn]

According to the 'Model rocket engine performance chart" in the current Estes catalog these are the max. lift weights for each motor:
E12-4: 17 oz.
B6-0: 4 oz.
So 17 oz. + 4X4 oz. = 33 oz.
Motor weights are 2.16 oz. for the E12, 0.55 oz. for each B6, 4.36 oz. total.
So 24.36 oz. rocket lift off weight is well within the max parameters.
If 2 of the four B6s fail to ignite you would still be within the max lift off weight parameter.
Again, I would ask Boyce customer service for an opinion on this combo.
It would be a simple BP cluster and easier to ignite than a composite/BP mix.
If that's a go then subbing C6-0s will give you higher altitude.
BTW did you add additional nose weight over the stock amount? Wondering how much.

 

[KILTED COWBOY]

According to the 'Model rocket engine performance chart" in the current Estes catalog these are the max. lift weights for each motor:
E12-4: 17 oz.
B6-0: 4 oz.
So 17 oz. + 4X4 oz. = 33 oz.
Motor weights are 2.16 oz. for the E12, 0.55 oz. for each B6, 4.36 oz. total.
So 24.36 oz. rocket lift off weight is well within the max parameters.
If 2 of the four B6s fail to ignite you would still be within the max lift off weight parameter.
Again, I would ask Boyce customer service for an opinion on this combo.
It would be a simple BP cluster and easier to ignite than a composite/BP mix.
If that's a go then subbing C6-0s will give you higher altitude.
BTW did you add additional nose weight over the stock amount? Wondering how much.

I started with the 4 pats of clay in the capsule . But I left the service module unglued so I can add additional weight as needed. I understand from another source that the balancing point would be about 15 inches from the base of the fairings. so will add weight to get me up past that. Maybe a bit heavier just in case.

 

[dpower]

According to the 'Model rocket engine performance chart" in the current Estes catalog these are the max. lift weights for each motor:
E12-4: 17 oz.
B6-0: 4 oz.<snip>

17 oz is *really* optimistic - a 17 oz rocket on a E12 might get 30 fps off a 5' rod, which is far under what I'd consider a safe speed. That said, a D12 or E12 center with B6 outboards should be enough for a 20 oz SV. While I do like the E12 motors, I wouldn't put one in my SV, I've had too many CATOs with them.

I started with the 4 pats of clay in the capsule . But I left the service module unglued so I can add additional weight as needed. I understand from another source that the balancing point would be about 15 inches from the base of the fairings. so will add weight to get me up past that. Maybe a bit heavier just in case.

My SV has the CG about 17" from the bottom of the fairings, fully loaded. This was based on a Verna's recommendation here: https://www.rocketryforum.com/threads/cg-cp-for-estes-saturn-v.23998/#post-213152

 

[Rocketjunkie]

I have done a 5 motor cluster with APCP in the center and BP in the outer 4. I used a "fast paper fuse" that burns at 0.1s/ft to 0.4s/ft, with a section going into the nozzle of the BP motors and held under the APCP motor.

Here's a video of a 4 motor cluster with a J350 'airstarting' 3 38/240 APCP Rx motors. I used 1-2 sec/foot ( https://www.skylighter.com/collections/firework-fuse ) 3 additional pieces of the very fast (white) folded over the top of the grain made sure the outboards lit. The J took its sweet time getting going and the outboards lit 1/2 sec later just as the J came up to pressure. I've been looking for an alternative to Thermalite And I have an assortment of speeds. Sheathing this fuse does NOT speed it up like Thermalite. If it takes less than a second to burn up the core you don't need to sheath it. Slower, just wrap it in masking tape. Here's a video of fuse tests. Very energetic Also, if it gets a kink or bent sharp over an edge, it's likely to go out at the damaged spot.

 

[John Taylor]

Yesterday I was reading a thread about the maximum lift off weight of a Quest D16 motor. The advertized maximum was around 95g. or so. This was commented on by several posters as seeming low for a D motor.
The insert included with the D16 motor reads:
D16-4 = 340grams max. lift off wt.
D16-6= 227 grams
D16-8= 170 grams.
Hope this helps.

 

[burkefj]

Remember, they are just into D range with 12.4ns, not a full 20ns D motor, but they are great for heavy 18mm models.

Yesterday I was reading a thread about the maximum lift off weight of a Quest D16 motor. The advertized maximum was around 95g. or so. This was commented on by several posters as seeming low for a D motor.
The insert included with the D16 motor reads:
D16-4 = 340grams max. lift off wt.
D16-6= 227 grams
D16-8= 170 grams.
Hope this helps.