MDRM Motors

[jackiboi_11]

Hello all, i’m about to start a mega der red max clone with a 29mm mount and was wondering the best motors to use for it (single use) because the recommendations i saw were for the stock mdrm not with plywood upgrades. I was thinking a G77-4R or G-80-7T. Any help is appreciated!

 

[Scott_650]

Either do a full sim with freeware Open Rocket, buy a copy of Apogee’s RocSim or get a solid “rule of thumb” recommended motor list with Thrustcurve.

You don’t have to create the sim file from scratch, there are several available here on TRF in various forums but most likely K’tesh has one done you can mod to match the heavier parts https://www.rocketryforum.com/threads/kteshs-openrocket-files-index.148212/

 

[jackiboi_11]

Either do a full sim with freeware Open Rocket, buy a copy of Apogee’s RocSim or get a solid “rule of thumb” recommended motor list with Thrustcurve.

You don’t have to create the sim file from scratch, there are several available here on TRF in various forums but most likely K’tesh has one done you can mod to match the heavier parts https://www.rocketryforum.com/threads/kteshs-openrocket-files-index.148212/

yeah but i can’t access openrocket at this point that is why i’m asking. Sorry if i didn’t make that clear.

 

[ThirstyBarbarian]

Hello all, i’m about to start a mega der red max clone with a 29mm mount and was wondering the best motors to use for it (single use) because the recommendations i saw were for the stock mdrm not with plywood upgrades. I was thinking a G77-4R or G-80-7T. Any help is appreciated!

I think any of the high-thrust single use G motors would be ok, but you probably want to stick with 4-second delays, not 7. G80 blue Thunder, G79 white, G78 green, G77 red. The lower thrust ones like G40 and G38 are probably not adequate.

You should probably weigh your competed rocket, after painting and everything, fully loaded with the recovery system, but without the motor. Then put that weight into a sim program, either a more detailed one like OpenRocket, or just a basic sim like ThrustCurve, and see if it works. ThrustCurve is a great resource for answering the question you just asked. Put in the weight and diameter, and search for single-use 29mm Aerotech motors — you’ll get a list of motors.

https://www.thrustcurve.org/

 

[cwbullet]

Hello all, i’m about to start a mega der red max clone with a 29mm mount and was wondering the best motors to use for it (single use) because the recommendations i saw were for the stock mdrm not with plywood upgrades. I was thinking a G77-4R or G-80-7T. Any help is appreciated!

It depends on your final weight. Do a SIM.

 

[Handeman]

The best is always the biggest! I205W

 

[Antares JS]

Hello all, i’m about to start a mega der red max clone with a 29mm mount and was wondering the best motors to use for it (single use) because the recommendations i saw were for the stock mdrm not with plywood upgrades. I was thinking a G77-4R or G-80-7T. Any help is appreciated!

7 second delay is almost guaranteed to be too long on a G. Mega Max is draggy and slows down quickly. Like @cwbullet said, and I did in an earlier thread, use OpenRocket or RockSim to run a simulation of your particular build.

 

[jimzcatz]

You actually want to build that 4" rocket with a 54mm mount. 54mm single grain motors are a lot of fun and you can always adapt down. good luck.

 

[NTP2]

I say a G79-4 should be good.

 

[jackiboi_11]

I say a G79-4 should be good.

Thats what i plan on using for now.

 

[jackiboi_11]

I

You actually want to build that 4" rocket with a 54mm mount. 54mm single grain motors are a lot of fun and you can always adapt down. good luck.

By the time i posted this thread the plywood parts were already ordered. I wanted to keep this a very low flyer but the help is greatly appreciated!

 

[NTP2]

Thats what i plan on using for now.

I love the green.

 

[jackiboi_11]

I love the green.

Mojave? Is that what you mean. I thought the 79 was the white lightning.

 

[jackiboi_11]

And you can use the G79 in the LOC Goblin right?

 

[NTP2]

Mojave? Is that what you mean. I thought the 79 was the white lightning.

Yes I can’t spell mojave. I miss remembered it is the 78

 

[jackiboi_11]

Yes I can’t spell mojave. I miss remembered it is the 78

Im pretty sure the 80 is the blue thunder, 79 is white lightning, 78 is mojave, and 77 is redline.

 

[NTP2]

And you can use the G79 in the LOC Goblin right?

Im pretty sure the 80 is the blue thunder, 79 is white lightning, 78 is mojave, and 77 is redline.

Yeah if you want this will help https://www.apogeerockets.com/Rocket-Kits/Skill-Level-4-Model-Rocket-Kits/Goblin scroll to the bottom where it says 29mm.

 

[jackiboi_11]

Thats where i originally looked but didnt see the g79

Yeah if you want this will help https://www.apogeerockets.com/Rocket-Kits/Skill-Level-4-Model-Rocket-Kits/Goblin scroll to the bottom where it says 29mm.

 

[jackiboi_11]

And you can use the G79 in the LOC Goblin right?

Still not sure

 

[David_Stack]

Still not sure

Open Rocket... It's free to download/install/use.

LOC Goblin Rocksim file attached (Open Rocket can read Rocksim files; pulled from the LOC site at https://locprecision.com/products/loc-goblin?_pos=1&_sid=04c1f1254&_ss=r)

You can also use ThrustCurve (thrustcurve.org) to enter general rocket characteristics and it will produce a list of motors that are recommended.

 

[NTP2]

Still not sure

I would just go with the G80 but I would wait until apogee changes the price to reflect recent changes in regulations for hasmat so you don’t pay it.

 

[NTP2]

Open Rocket... It's free to download/install/use.

LOC Goblin Rocksim file attached (Open Rocket can read Rocksim files; pulled from the LOC site at https://locprecision.com/products/loc-goblin?_pos=1&_sid=04c1f1254&_ss=r)

You can also use ThrustCurve (thrustcurve.org) to enter general rocket characteristics and it will produce a list of motors that are recommended.

He is on vacation and cannot access it please read the thread.

 

[jackiboi_11]

Open Rocket... It's free to download/install/use.

LOC Goblin Rocksim file attached (Open Rocket can read Rocksim files; pulled from the LOC site at https://locprecision.com/products/loc-goblin?_pos=1&_sid=04c1f1254&_ss=r)

You can also use ThrustCurve (thrustcurve.org) to enter general rocket characteristics and it will produce a list of motors that are recommended.

I cannot access openrocket at this time.

 

[jackiboi_11]

I would just go with the G80 but I would wait until apogee changes the price to reflect recent changes in regulations for hasmat so you don’t pay it.

Im not going to buy it from apogee. Im going to get the LMS from ASP because its only $29

 

[NTP2]

Im not going to buy it from apogee. Im going to get the LMS from ASP because its only $29

Do tell me more do you have a link?

 

[jackiboi_11]

Do tell me more do you have a link?

Here is the 4 sec delay one

https://www.asp-rocketry.com/ecomme...-Engine.cfm?item_id=1053&parent=89&navPanel=1

 

[dpower]

My MDRM weighs 36 oz, and flies fine on just about any AT G motor (though I usually fly on the H210 or I200.

G64, G77,G78,G79, a 5.5s delay is ideal. A G80-7 would be long, but at 900’, would still work.
One nice thing about LMS is that the delay can be adjusted. Buy the -7, and drill out 1 or 2 seconds, if your weight turns out close to mine.

It would even fly ok on an F50-4, though just 400’. Again, if your weight is 36 oz.

If it ends up weighing much more, you may not have sufficient speed off of a rail on any of these motors.

 

[jackiboi_11]

I got the 1/4 inch plywood fins and rings and i haven't weighed yet but definitely weighs a good amount.

My MDRM weighs 36 oz, and flies fine on just about any AT G motor (though I usually fly on the H210 or I200.

G64, G77,G78,G79, a 5.5s delay is ideal. A G80-7 would be long, but at 900’, would still work.
One nice thing about LMS is that the delay can be adjusted. Buy the -7, and drill out 1 or 2 seconds, if your weight turns out close to mine.

It would even fly ok on an F50-4, though just 400’. Again, if your weight is 36 oz.

If it ends up weighing much more, you may not have sufficient speed off of a rail on any of these motors.

 

[ThirstyBarbarian]

The question you are asking about whether these motors will work for your MDRM and LOC Goblin will depend entirely on the weight of your finished rockets. You don’t know what your rockets will weigh at this point, and it sounds like with the MDRM fin mods, you don’t even have a rough idea. And LOC’s estimated kit weights are always wrong by a LOT. Unless you need to buy the motors now for some reason, you might want to wait until you have an idea what your rockets are going to weigh.

 

[jackiboi_11]

The question you are asking about whether these motors will work for your MDRM and LOC Goblin will depend entirely on the weight of your finished rockets. You don’t know what your rockets will weigh at this point, and it sounds like with the MDRM fin mods, you don’t even have a rough idea. And LOC’s estimated kit weights are always wrong by a LOT. Unless you need to buy the motors now for some reason, you might want to wait until you have an idea what your rockets are going to weigh.

I get it, I need to order the motors befroe the end of this week because of a family event where im going to set it off.