Aerotech Sumo Motor Spacing for Single Use G Motors

Hello, all. This is my first post. Been into hobby rocketry for about 1.5 years, now, and I am just starting to get into mid-power with the hope of eventually getting Level 1 certified.

I am in the process of building an Aerotech Sumo, and I have a few questions, if anyone would be so kind as to help.

1. What does this sentence in the instruction manual mean? "Use 3/4” masking tape for single use motor spacing." Where does the tape go? I have a G80, and it slides right in, is blocked by the aft closure in front, and the motor hook in back. So what is the tape for? Doesn't look like the motor can move.
2. Also, for RMS motors, they give you two spacer rings. Since I have never bought or held an RMS motor, where would the rings go?
3. Last, in the spring, I want to use this to L1 certify before I get into dual deployment. Obviously I have never used an HP motor, and I'm sure there is a lot I don't know. Would someone lay out the basics for me (assume I am stupid), like what casing to buy, what reload it to buy, anything else I need that I don't know about? Etc.

Thanks!

Welcome to TRF!

I don't have a Sumo so I can't tell you what the tape is supposed to be for. I can say that HPR and most MPR rockets don't use motor stops or a motor hook. The motor mount tube (MMT) is left open on the forward end so you can put various length motor casings in it. The aft end of the motors have thrust ring built into them that prevents them from going completely into the MMT. The issue with the motors is retention. Keeping the case in the rocket during chute ejection. Masking tape can be used for this by wrapping some around the motor so it is a tight fit in the MMT and the friction holds the motor in.

As for a L1 RMS case, you have several choices. Aerotech being one and Cesaroni being the other popular one although there are others available like Loki. I would suggest checking with the vendors at your local field and find out which types they are offering certification specials on and what types of reloads they handle the most.

I would highly recommend you get an Aerotech 24/40 and 29/40-120 RMS Hobbyline cases and fly MPR on those cases for a while. Don't rush the L1. Fly the Hobbyline for a while and learn more about flying RMS and larger MPR. Then when you want to go for L1, I would recommend a 38mm case so you can fly the full range of H and I motors.

Anyway, hang out here, talk with the guys at the local field, fly a lot of rockets and have fun.

As the above post he sumed it up. I have the SUMO and I would have to look them over. As far as motor retention you can go with Aeropack retainers. Leave out the thrust ring and you can fly a wider range of motors.

There are a stunning amount of options for L1. A few basics:

For 29mm Commercial loads, you're looking at Aerotech or Cesoroni.
https://www.pro38.com/products/pro29/motor.php
https://www.aerotech-rocketry.com/products.aspx

Aerotech involves more building while assembling motors. Cesoroni or CTI you just pull off the delay, drill it, and slide it in. AT cases are more expensive, the reloads are however cheaper and almost all ship without hazmat fees (just the H97 needs hazmat) All CTI ship hazmat.

These are some AT reloads.

A couple burned CTI loads for the 29 3 grain case (G54R and an H133BS)


As for which to get don't ask me. I couldn't decide. I love both. CTI is simple, but AT is fun to build. I can build a motor in under 5 minutes now. Get a 29 40-120 case and practice now and it'll be simple later. Plus $10 reloads are awesome.

Thanks for all the replies!

DizWolf, love the beer bottle next to the explosives.

I'll be back with more Q's.

Here I am already.

So, if I buy this https://www.hobbylinc.com/htm/aro/aro91291.htm I get the case and one preloaded motor, or is this just the case?

Same question for this Rouse Tech. Looks like it can use E thru H motors, while the AT can only use E thru G, correct? So even tho more expensive, the RT is more flexible and support both hobby and HPR motors...?

Oops, here's the Rouse Tech https://www.apogeerockets.com/Rocket_Motors/Rouse-Tech_Casings/29mm_Casings/RMS-29_40-120

Bat-mite said:

Here I am already.

So, if I buy this https://www.hobbylinc.com/htm/aro/aro91291.htm I get the case and one preloaded motor, or is this just the case?

Same question for this Rouse Tech. Looks like it can use E thru H motors, while the AT can only use E thru G, correct? So even tho more expensive, the RT is more flexible and support both hobby and HPR motors...?

Click to expand...

Bat-mite said:

Oops, here's the Rouse Tech https://www.apogeerockets.com/Rocket_Motors/Rouse-Tech_Casings/29mm_Casings/RMS-29_40-120

Click to expand...

Both the Aerotech and Rouse Tech 29-40/120 cases are only for Hobbyline E through G motors. There is a high power G138 load available for it, but it can't be used for a Level 1 cert flight, even though you have to be Level 1 to purchase and fly it. The biggest mid power G load would be the G64 or G76. For H and above reloads you'd need a Rouse Tech (or Aerotech if you can find one) 29/120, 29/180, etc., depending on the load.

Those are just the cases / hardware. The reloads you buy separately

Bat-mite said:

Oops, here's the Rouse Tech https://www.apogeerockets.com/Rocket_Motors/Rouse-Tech_Casings/29mm_Casings/RMS-29_40-120

Click to expand...

If you look around you can pick it up for less... a lot less. Under $50

AfterBurners said:

If you look around you can pick it up for less... a lot less. Under $50

Click to expand...

Sirius is $39 currently

Oh, all the motors are unloaded. .
also, Propellant is a flamable solid, not explosive. Subtle difference but it matters.

I'm still confused. The description for the Rouse Tech reads as follows: "The 29mm diameter high power motor cases allow you to take an existing 29mm rocket and put an H or I-size motor in it. Since an H-size motor is the first high power motor, you can get your Level 1 certification using a sturdy-built existing kit! These 29mm casing are very popular for that very reason."

???

The high power case is little longer that the hobby line as I recall.

AfterBurners said:

The high power case is little longer that the hobby line as I recall.

Click to expand...

This is correct. The 29/40-120 is different than the regular cases. While there a multitude of reloads for it only the reloads for the 29/40-120 will fit and can be used. Additionally, the reloads for the cases such as the 29/60, 29/120. 20/180 etc will only fit those cases and those cases cannot use the reloads for the 29/40-120.

If you are just beginning with reloads I would suggest the 29/40-120 ... lots of reloads, good price and gets you used to reloading motors. When you are ready for the L1 get a used 29/180 or similar in size off ebay or here in our Yard Sale section.

The last thing I would suggest is you download and print the reload schematics for all of the loads of each case you have and take that in a binder to the field. refer to it every time you are putting together a reload to make sure you get and the O-rings and seal in their proper place. The schematics can be found here. doing this has helped me so much.

Also ... to address your original question about the tape ...

Not sure I saw the answer above so if I am repeating I apologize ... The original single use motors did not have the thrust ring at the aft end of the motor like the current Aerotech SU motors do. Therefore you had to use masking tape wrapped around the aft-end of the case to keep it from sliding up and through the motor mount tube.

Good luck.

Good luck.

Thanks. Everything is starting to make sense, now.

I looked at the Sumo specs. It can take, for example, an H128W-S and an H165R-S. I look at the chart and see that both of those will fit in an RMS29-180 case. I look at the case specs, and it can take a G75J, H128-W, H165-R, and H238-T.

Looking at the motor designator for, say, the H128W-S, I learn the following: it is H impulse, the prop. type is "White Lightning", and I am assuming the "-S" means "short" delay, since the only options seem to be "S" and "M". Is that correct? I am only used to the SU designators that tell you the delay seconds, like G80-7T or F26-6.

In summary, my Sumo with its open-ended 29mm motor tube can use hobby E thru G motors in an RMS29/40-120 case. To step up to H impulse for my cert. flight, I will need at least an RMS29/180.

Right?

Bat-mite said:

Thanks. Everything is starting to make sense, now.

I looked at the Sumo specs. It can take, for example, an H128W-S and an H165R-S. I look at the chart and see that both of those will fit in an RMS29-180 case. I look at the case specs, and it can take a G75J, H128-W, H165-R, and H238-T.

Looking at the motor designator for, say, the H128W-S, I learn the following: it is H impulse, the prop. type is "White Lightning", and I am assuming the "-S" means "short" delay, since the only options seem to be "S" and "M". Is that correct? I am only used to the SU designators that tell you the delay seconds, like G80-7T or F26-6.

In summary, my Sumo with its open-ended 29mm motor tube can use hobby E thru G motors in an RMS29/40-120 case. To step up to H impulse for my cert. flight, I will need at least an RMS29/180.

Right?

Click to expand...

Yeah you got it. The 29/40-120 is a great case and you will get a lot of use out of it for the Sumo and any other 29mm rockets you have. I think the Sumo is a great kit (my son and I are finishing one) and it will be a good one for you eventual L1 cert. I did my L1 on a NCR Big Brute that we dubbed "Black Widow"

Here is a pic of my two sons holding the Black Widow last year shortly after I got the L1.



As you can see it is a "fatty" like the Sumo which makes it a good L1 cert kit. Initial test flights were G76-7G. We used an H97-JM in the 29/180 case for the L1 and but for a tad longer delay than I would have liked it was a perfect flight and we never lost sight of it. We have since used an H165-RM and an H180-WM and all were perfect.

Bat-mite said:

I'm still confused. The description for the Rouse Tech reads as follows: "The 29mm diameter high power motor cases allow you to take an existing 29mm rocket and put an H or I-size motor in it. Since an H-size motor is the first high power motor, you can get your Level 1 certification using a sturdy-built existing kit! These 29mm casing are very popular for that very reason."

???

Click to expand...

I see why you're confused. I attached a pic of the page you were looking at. The Blue circled area is for the RT Hobbyline 29/40-120 case. The red circled area is what they call their "Monster" motor series. These are High power cases. The text in the red circled area is not describing the 29/40-120 cases above The reloads for the two types are cases are not compatible.

Handeman said:

I see why you're confused. I attached a pic of the page you were looking at. The Blue circled area is for the RT Hobbyline 29/40-120 case. The red circled area is what they call their "Monster" motor series. These are High power cases. The text in the red circled area is not describing the 29/40-120 cases above The reloads for the two types are cases are not compatible.
View attachment 156421

Click to expand...

yeah that is a bit confusing ... and this type of misleading web page creation is unfortunately not uncommon in our hobby.

AfterBurners said:

The high power case is little longer that the hobby line as I recall.

Click to expand...

They have different closures, too. The high power cases can be from 5" long (29/120) to 12-1/4" (29/360).

The 29/60 and 29/100 are also high power style cases and closures. With the very limited motor selection, they're not very popular. I've never flown mine.

DizWolf said:

The 29/60 and 29/100 are also high power style cases and closures. With the very limited motor selection, they're not very popular. I've never flown mine.

Click to expand...

I bought the 29/60 for the sole purpose of using it in a couple 29mm Quest brand rockets that I put the motor block in before knowing better. Other than that it is pretty much useless because as far as I can tell there are only two reloads for it.

SacEsq said:

I bought the 29/60 for the sole purpose of using it in a couple 29mm Quest brand rockets that I put the motor block in before knowing better. Other than that it is pretty much useless because as far as I can tell there are only two reloads for it.

Click to expand...

But the closures can be used with the other 29mm HPR cases, so you only need to buy another case, such as the 29/180 or 29/240 to increase your options. You don't need to buy more closures.

That said, the only 29mm case I have is the hobby line 29/40-120. After that, I focused on the 38's and 54's. Between the 29/40-120 and the 38's, I just didn't see much need for the 29mm HPR motors...provided I put a 38mm (or larger) tube in the rocket

Doug

.

For me, the HP 29s are all about dodging hazmat

plano-doug said:

But the closures can be used with the other 29mm HPR cases, so you only need to buy another case, such as the 29/180 or 29/240 to increase your options. You don't need to buy more closures.

That said, the only 29mm case I have is the hobby line 29/40-120. After that, I focused on the 38's and 54's. Between the 29/40-120 and the 38's, I just didn't see much need for the 29mm HPR motors...provided I put a 38mm (or larger) tube in the rocket

Doug

Click to expand...

DizWolf said:

For me, the HP 29s are all about dodging hazmat

Click to expand...

I agree with Doug, but DizWolf has a point too.

What I tend to do is stick with one size, like 29/180 & 29/240 for H motors and go to the 38/360, 480, & 600 for I motors. That saves me money on the H loads without spending money on the smaller 38 cases to fly H. Where the differences really show up is between 38mm and 54mm. I have a 38/720 for small J motors, but a 54/1280 for large J. The 54/1706 for small K and the CTI 6GXL with spacers for large K and baby L motors.

What I've found is that the same Ns load in a smaller diameter will be cheaper then the larger diameter. I can get a J350W 38/720 at 700 Ns for $58 while a J250FJ 54/825 at 731 Ns is $73