1st MPR build Madcow Tomach

I havent seen one for the Tomach. the screech is nearly identical- rocksim is on the bottom of the page. Adjust for your final weight and should ballpark it for you. https://www.madcowrocketry.com/2-6-thin-wall-fiberglass-dual-deploy-screech/


some quick and dirty numbers for my build=

Tomach minimum diameter is a much better performer than a Screech. I'll try to post a Tomach tomorrow.

dixontj93060 said:

Tomach minimum diameter is a much better performer than a Screech. I'll try to post a Tomach tomorrow.

Click to expand...

This appears to be a 2.6" Tomach...... Just released with a 38mm mount.

So back from vacation and did a little more work
Finish the last fillet, this set did not come out perfect so I will have a little work cleaning it up


I do have a question the coupler that goes into the nose cone should that be epoxyed in the nose cone or should I rivet it in for future changes like a tracker or something



IJEEPIN
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I thought all the Tomach sizes were minimum diameter? Or are they all 54mm, and the 38mm airframes have a different name?

I am probably not going to do minimum diameter for a while but I have been kicking ideas around, and these seem like nice kits.

watermelonman said:

I thought all the Tomach sizes were minimum diameter? Or are they all 54mm, and the 38mm airframes have a different name?

I am probably not going to do minimum diameter for a while but I have been kicking ideas around, and these seem like nice kits.

Click to expand...

Only the 54 is, check out MMT sizes on the others. Plus I think like, only 4 people are still flying Kosdon 2.5's

Got a little bit of work done today



IJEEPIN
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DizWolf said:

I havent seen one for the Tomach. the screech is nearly identical- rocksim is on the bottom of the page. Adjust for your final weight and should ballpark it for you. https://www.madcowrocketry.com/2-6-thin-wall-fiberglass-dual-deploy-screech/


some quick and dirty numbers for my build=

Click to expand...

How many and what size vent holes did you use
On the screech and where did you place them


IJEEPIN
Paul Sandyck
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For the av bay, three vents. Don't recall the size I'll have to check. I also vented the payload and booster with one 1/4" hole each.

For the statologgerCF for a 3" dia it says 4 holes .025
I was going to do 3 holes too


IJEEPIN
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.025 is smaller than 1/32 so what should I use to vent the eBay


IJEEPIN
Paul Sandyck
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Can I just attach the ematch right to the altimeter


IJEEPIN
Paul Sandyck
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djpaulys said:

Can I just attach the ematch right to the altimeter


IJEEPIN
Paul Sandyck
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Click to expand...

As opposed to what?

Running a wire to the block terminal on top of bulkhead


IJEEPIN
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djpaulys said:

.025 is smaller than 1/32 so what should I use to vent the eBay


IJEEPIN
Paul Sandyck
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Click to expand...

those sizes are way too small. sure, they'll work, but they don't need to be that small. there have been many conversations regarding vent hole sizes on this forum. for a 2.6" I would use 3/32" - 1/8" holes depending on the length. check out the vent sizes missile works recommends for their altimeters. my last rocket flight had a stratologger CF as primary and a missile works RRC2+ as backup in a 54mm bay. the three vents are .110" and the two altimeters reported a max altitude within 5 feet. one 1/8" hole for booster and payload vent is probably fine as well.

djpaulys said:

.025 is smaller than 1/32 so what should I use to vent the eBay


IJEEPIN
Paul Sandyck
Membership Officer
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Click to expand...

It is not critical. Use an 1/8'' bit and drill three holes. Boom, done. Vehicle speeds as it relates to pressure at apogee and main deployment events are inconsequential to the electronics.

djpaulys said:

Running a wire to the block terminal on top of bulkhead


IJEEPIN
Paul Sandyck
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Click to expand...

I see. Well that would be dependent on your configuration. Terminal blocks allow the convenience of quick replacement of the ematch outside of a sealed avionics bay.

djpaulys said:

Can I just attach the ematch right to the altimeter


IJEEPIN
Paul Sandyck
Membership Officer
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Click to expand...

that's how I do mine. just make sure you can get both matches to the altimeter. I seal the hole in the bulkhead with some of my kids modeling clay.

DizWolf said:

Only the 54 is, check out MMT sizes on the others. Plus I think like, only 4 people are still flying Kosdon 2.5's

Click to expand...

Ah you forgot the CF models. They are both MD and available in 54mm and 98mm...I have my eye on the 98mm https://www.madcowrocketry.com/98mm-carbon-fiber-tomach/

mpitfield said:

Ah you forgot the CF models. They are both MD and available in 54mm and 98mm...I have my eye on the 98mm https://www.madcowrocketry.com/98mm-carbon-fiber-tomach/

Click to expand...

I did indeed forget the CF 98 They did just release a glass 98, but it has a 75 mount.

That CF 98 is gonna be a trip out west

Is it ok to do ground test with out chutes or will that not give you a good test


IJEEPIN
Paul Sandyck
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djpaulys said:

Is it ok to do ground test with out chutes or will that not give you a good test IJEEPIN Paul Sandyck Membership Officer /|_|,[______], I--I--L--OIIIIIIIO- ( )_) ( )_)--o--)_)

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You flying without a chute?

Ok point taken


IJEEPIN
Paul Sandyck
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djpaulys said:

Is it ok to do ground test with out chutes or will that not give you a good test


IJEEPIN
Paul Sandyck
Membership Officer
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Click to expand...

Always test as you plan to fly...pack the laundry, just make sure you have the chute covered with your Nomex. Some guys on the forum have reported burning their chutes with ground tests, a bad way to ruin it. Alternatively use something that uses about the same packed volume, substitute it for your chute and roll in your Nomex. That way you are testing accurately and not risking your nice chute just for a ground test. This is how I test now; well when I remember!

I burned up a chute in nomex ground testing. The charge was too small and just cooked it. I recommend an old tshirt or rag for groind testing now....

Thanks for the tips


IJEEPIN
Paul Sandyck
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dont use rags from the garage soaked in gasoline. it's bad.... i hear...

DizWolf said:

dont use rags from the garage soaked in gasoline. it's bad.... i hear...

Click to expand...

If you do, please video it and post the results

I have video.....

DizWolf said:

I have video.....

Click to expand...

lol...sounds like it could of been a Darwin award moment. Obviously it turned out okay?