Motor casing longer than mmt

Hey guys,
I cant find any specs for how long the mmt is on the rocket that i plan on ordering, so is it a problem if the motor casing (cesaroni 38mm) sticks out of the mmt?
Also the aeropack 38mm p retainer fits fiberglass right?

Not sure about the Aeropack, but I've never had a problem when the case extends past the MMT.

Ok, thanks

correct thats not a problem. the motor mount is just to center the motor. the motor mount could be 8" long and the motor 25" if it could fit in the rocket.

38P is good for glass....going to need a bit of sanding still.

Ok thanks.
When you are creating an nar membership, it asks for two sections, what does this mean?

littlemisterbig said:

Ok thanks.
When you are creating an nar membership, it asks for two sections, what does this mean?

Click to expand...

sections are clubs like SMASH is #500

Decided to go with a 2.6 inch arcas hv instead of the dx3, because its out of stock. I might just wait for the dx3 to be back in stock.

I wouldn't go too overboard on the length difference (like a 20" motor in a 4" long tube), but it's typically OK. Move vendors are really good at answering questions alike this, and another option is to google for a rocksim file for the kit, and look to see how long the Motor tube is.

The "p" is for FG and Blue Tube, and the "l" for kraft.

First, a lot of assumptions being made to say its okay......
The first thing you want to look at is mass distribution to ensure the stability of the rocket remains with a good cp/cg relationship. hard to do without owning the kit. (a reason its good to look at manufacturer recommended motors.) I like kits that have published CP and maybe even a rocksim file easily available.

secondly, you need to look at how it affects the recovery methods. Like shock cord attachment. How it affects the harness storage etc...

For the motor case to mount lengths, there are no respective rules. If you think about it, the motor tube is not even required. it just makes centering the motor easier and provides some benefits of making it easier to seal the airframe for ejection charges to work properly. In other-words reduces the leakiness that causes larger ejection charges to be required.
the mount length also has a benefit of helping the load distribution from the motor thrust to the airframe, and reinforcing the fin roots. I always use the mmt to have atleast a secondary harness attach point, if I am using the motor for the primary harness point.

Good luck with the arcas, I have always liked that rocket.

The motor mount for the Madcow ARCAS is 8". As far as it being shorter than the motor mount that is not really an issue but I would be careful not to go overboard with it. The point of the MMT is to mount the motor and the CR is to center the motor. The motor mount is not a necessity i.e. you can use the CR to center the motor itself. As aforementioned it helps for inner fillets (stronger fin attachment) on the fins so you might check the length for that as it is a benefit (FYI on the ARCAS it is long enough). The Aeropack retainer will work and retainer the motor from the aft. All this combined is an OK configuration.

The ARCAS is a nice rocket. I have never flown one but I have flown the DX3. I would favor the ARCAS.

Ok then, I'll go with the arcas, thanks.

littlemisterbig said:

Ok then, I'll go with the arcas, thanks.

Click to expand...

I think you may have an incorrect NAR# in your sig! I think the numbers are just over 105,000 these days for new members

Im sure it says 210602

littlemisterbig said:

Im sure it says 210602

Click to expand...

What is the number on your NAR card? Are you sure you're not looking at an Order # or Invoice number or something? The highest number with HPR certifcation is less than 100,000, and there are only a few thousand new members every year. (and some people Cert a short time after joining - I got my L1 the next launch after I got a card, for example) If you haven't got your card, you might not have a NAR # yet.

Here's the offical list of people with at least L1 cert: https://www.nar.org/high-power-rocketry-info/nar-hpr-certified-members/

OOOOOH, thats my account number. When do i get a membership card?

littlemisterbig said:

OOOOOH, thats my account number. When do i get a membership card?

Click to expand...

2-3 weeks. You'll get a card and some other stuff as a new member. Seems the cards are requested once a week by NAR HQ from the printer, then it takes a week or so to produce the cards, and then US mail. If you need to prove you're NAR before you get the card, take a copy of the invoice with you, to prove your a member - but the only time I can see this is if you join a local club or go for a cert flight.

Oh, and before you build something that "almost" flies on a MPR motor (e-f-g), build and fly something that is designed for an e-f-baby g, and fly it a few times to get your bearings. And if there is a local club, join it, as there are people there to help you get started and give you suggestions on building.

After getting my L3 years ago, I'm back doing MPR, and I can tell you, without a doubt, my MPR and L1 stuff is built FAR differently today than when it was built before I got L1. And that's things I learned from people with more experience along the way. It's not a goal, but a journey, and the journey is the important part!

I just joined NAR a week or so ago in advance of trying for my L1 this coming weekend, and I had the same issue --- they don't tell you your member number right away, and so you assume it is the same as the account number you get immediately. I called NAR to verify the number, and they gave me my real NAR number over the phone, and it is different from the account number. They told me to print out my confirmation email and write my member number on it, and that should be adequate for identifying myself for the cert paperwork. You can get the phone number from their website, then give them a call to get your number.

OK thanks.