Aerotech Sumo kit parts

So I just got an Aerotech Sumo kit [Thank you, Wildman ], and instead of the 2.54 inch bulkhead disk listed in the instructions, which forms part of the baffle and acts as the shock cord mount, it has a 4 inch bulkhead disk. I'm not sure if they updated the kit without updating the instructions or it was just packaged with the wrong part included.

So, this bulkhead would cover the entire diameter of the body tube, so obviously it can't go in as is, but it leaves me with several good options. The simplest is probably just to drill 4-6 half inch holes in it and use it as expected. The instructions say not to glue it to the rest of the baffle, so that you can remove it and replace the shock cord, but I could also now have the option of gluing it in place and sealing it to the body tube which I wouldn't be able to do with the smaller disk. And I'd just use a quick link for the shock cord.

Or I could leave off the bulkhead there and use it somewhere else in the rocket, if anybody has a good suggestion, maybe leaving off the baffle entirely.

The only other mods I'm planning on are ditching the motor hook for a screw on retainer, putting some mount points for rail buttons in addition the lugs, and putting the piston in backwards. And maybe upgrading the recovery system.

I could be wrong but I'm pretty sure the areotech sumo doesn't come with a baffle like the rest of there kits, it uses a piston ejection method to deploy the parachute by were it pushes the bulkhead up the body using the ejection charge from the motor then pushing the nose cone off and deploying the parachute.

It has a small baffle piece that fits into the end of the motor mount tube, and then a bulkhead with the shock cord mount that sits on top of that which basically acts as the rest of the baffle. It does have a piston which goes above this. The bulkhead with the shock cord is the one I'm talking about, which in the instructions is shown as a 2.54" diameter, but which I got as a full 4" diameter bulkhead.

Overall a pretty easy kit to build, but once I got to the step where I was testing the fit of the fins, I looked at it and was severely tempted just to put a nose cone on it looking like this:

As JennZ stated, Sumo has no baffle like their other kits. It uses the piston system. I modified mine to fly without the piston after it lawn-darted on a recent flight. Ended up going with conventional motor eject with no baffle.

timbucktoo said:

As JennZ stated, Sumo has no baffle like their other kits. It uses the piston system. I modified mine to fly without the piston after it lawn-darted on a recent flight. Ended up going with conventional motor eject with no baffle.

Click to expand...

I eliminated the piston too. Nomex and the 42" chute worked fine on my L1 flight

flyskippy1 said:

So I just got an Aerotech Sumo kit [Thank you, Wildman ], and instead of the 2.54 inch bulkhead disk listed in the instructions, which forms part of the baffle and acts as the shock cord mount, it has a 4 inch bulkhead disk. I'm not sure if they updated the kit without updating the instructions or it was just packaged with the wrong part included.

So, this bulkhead would cover the entire diameter of the body tube, so obviously it can't go in as is, but it leaves me with several good options. The simplest is probably just to drill 4-6 half inch holes in it and use it as expected. The instructions say not to glue it to the rest of the baffle, so that you can remove it and replace the shock cord, but I could also now have the option of gluing it in place and sealing it to the body tube which I wouldn't be able to do with the smaller disk. And I'd just use a quick link for the shock cord.

Or I could leave off the bulkhead there and use it somewhere else in the rocket, if anybody has a good suggestion, maybe leaving off the baffle entirely..

Click to expand...

Had the same problem in a Sumo I bought a couple years back. Did some rough cutting with a band saw (hacksaw would do too) then chucked the remaining slightly oversize disk into a drill and sanded it down to size.

flyskippy1 said:

The only other mods I'm planning on are ditching the motor hook for a screw on retainer, putting some mount points for rail buttons in addition the lugs

Click to expand...

+1 on ditching the hook for an Estes style retainer. Not likely you will need the lugs, but buttons are also a good upgrade. If you have some spare 4" coupler, beefing up the airframe below the aft bulkhead is not a bad idea. It tend to hit the ground first and gets dented.