Pro150 motor andd Other O motor question

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Lukun7

Young Rocketeer
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The Woodlands, Texas (Near Houston)
On thrustcurve motor browser, I've noticed that the contrail and Gorilla Os are 152mm, and Cesaroni reloads are 161mm. Are these motors really the same diameter? And if not, which MMT size is used more and easier to find?
 
152 mm is 6". CTI '6"' motors really are 161 mm (6.3"). They will not fit a 6" mount.
 
curtis Turner makes them...probably Madcow custom order. referred to as 6 1/4 motor mount tube.
 
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Put in vertical stringers and centering rings for the largest diameter casing without using a motor tube. Make an adapter out of centering rings and all-thread for the smaller sizes. For the CTI casing, you will want to locate the centering rings where the larger diameter steps are.
 
P-8000 does not use a motor tube. It is a single use motor made of carbon fiber.
Slightly shaped like a "bell" the front end has a steel ring with 1/4in bolt holes in it . Motor is bolted to a aluminum CR glued inside the airframe. Requires approximately 10in. diameter of space. Nozzle end about 9.5 in.
No other support, just the 6 bolts in front to CR which doubles as the thrust ring.

I have one in storage for my Sparrow-Arcus full scale.
 
P-8000 does not use a motor tube. It is a single use motor made of carbon fiber.
Slightly shaped like a "bell" the front end has a steel ring with 1/4in bolt holes in it . Motor is bolted to a aluminum CR glued inside the airframe. Requires approximately 10in. diameter of space. Nozzle end about 9.5 in.
No other support, just the 6 bolts in front to CR which doubles as the thrust ring.

I have one in storage for my Sparrow-Arcus full scale.

Could you share pictures of the motor?
 
P-8000 does not use a motor tube. It is a single use motor made of carbon fiber.
Slightly shaped like a "bell" the front end has a steel ring with 1/4in bolt holes in it . Motor is bolted to a aluminum CR glued inside the airframe. Requires approximately 10in. diameter of space. Nozzle end about 9.5 in.
No other support, just the 6 bolts in front to CR which doubles as the thrust ring.

I have one in storage for my Sparrow-Arcus full scale.

Yeah, that would be nice. Do you mean that by gluing it into your CR you are basically making the motor disposable? Or can you take out or reload the Carbon fiber motor casing?

Reread that line. The P8000 is a single use motor.
 
You don't need a tube. Just cut enough rings.

Why doesn't anyone do this on smaller rockets? I mean, it's nice and all to glue your fin tabs to a mmt tube but the same thing could be accomplished with a stringer between rings I guess...
 
Why doesn't anyone do this on smaller rockets? I mean, it's nice and all to glue your fin tabs to a mmt tube but the same thing could be accomplished with a stringer between rings I guess...
A motormount tube within the airframe tube on smaller rockets is more rigid with less weight than stringers. For heavier/large rockets, plywood stringers give better lengthwise rigidity when that's more important than total weight. The centering rings give a more accurate way to center the motor than the stringers alone, and give additional strength.
 
Do you mean that by gluing it into your CR you are basically making the motor disposable?
Reread Jim's response again. The motor is bolted to a CR which is glued into the airframe, the motor isn't glued to the airframe.
 
Motor in shipping box only 30in long.

100_9355.jpg

Front end showing head end igniter receiver cap removed/doubles as inspection port to grain interior. Until actual igniter installed.
That igniter has 2 e-match wires imbedded into metal "mini motor" consisting of BKNO3.
Igniter has 350lbs of thrust for .33 sec
Note the black flat ring with 6 threaded holes. This is where motor is bolted on.
In real life "use" [military] this is a booster motor and uses exploding bolts. After burn it is jettisoned.
There is no real first stage with fins. Motor just bolts to rear of sustainer hangs in air.
It was made for the "affordable weapons systems' MINI Tomahawk cruise missile. {not the big one]
100_9357.jpg

Looking down from front of 12in. fincan to AL bulk plate.
This was the fitting for future install .
2 long 1/4in. all thread placed in motor bolt hole .
Then BP slid onto it.
12 inches of coupler glued into the 12in airframe on both sides of BP turning that into a permanent thrust wall/plate
Finally after all was correctly fitted, 6 sections of all thread cut for studs
4 of them had coupler nuts with Eyebolts in them on one end.
When installed through thrust plate into motor & nutz tightened, the recovery harness attached to E-bolts.
Essentially having all related stresses going directly to motor.
100_9374.jpg


PS this now being refitted for another flight.....
It will become the sustainer for a 2-stage flight at LDRS this Sept.
 
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