Aerotech 18MM rms

Has anyone tried cutting down the propellant grain in an 18 mm D24 reload to get performance closer to the c size motors? Making a new grain adapter spacer seems easy enough. I am just wondering if anyone has experimented with something like this?

That would make it a research motor. I have C motors by AT and that is essentially what they are but I think they have a spacer.

If you alter them, you have to TRA level 2 and fly them at a TRA research launch or fly them on you own. It would also nullify the warrantee on the motor so I would recommend against it.

Thanks for the info CW I only launch alone, pretty limited scene here, but I tried it out this weekend, worked well in a Quest Harpoon, used half the grain of a D24, nice boost very similar performance to an Estes C motor, recovery was just as expected. I am really just trying to find things to do with all the 18MM reloads i bought, they are way more powerful than i expected.

Aerotech actually produced and sold B6, C4, C6, C12, and E27-4 reloads for the Aerotech RMS-18/20 case back in the early 1990s. They discontinued a few years later the mid 90s due to low sales.

You can get "spare parts" here to use the other half of your propellant grains:https://www.rocketmotorparts.com/18mm_Model_Rocket_RMS_EMKs/cat1577810_3168267.aspx

They also have delay grains that you can cut to size for that 18mm. case.

Wow guys thanks so much for the input! I had heard about the smaller impulse reloads but was not a BAR until after they were discontinued. I have been looking for ways to use the other part of the propellant grain and that website looks like it should be able to supply everything i was looking for with one stop shopping to boot! Thanks so much too both of you for your input, there is something so much more satisfying launching on the RMS system over traditional BP motors, for me that is. Chris

mwtoelle said:

Aerotech actually produced and sold B6, C4, C6, C12, and E27-4 reloads for the Aerotech RMS-18/20 case back in the early 1990s. They discontinued a few years later the mid 90s due to low sales.

Click to expand...

Actually, these 18mm reloads lasted less than a year.
AeroTech did not receive any re-orders for them so in the "Great Motor Purge" of late 1992 I removed them from the order forms.

A really good use for AT 18 mm reloads is for all of those Estes 'Lead Sleds' that Estes recommends a C6-3 for. Rockets like the Mercury Redstone, and Venus Probe which are barely marginal on a C will actually fly real nice on an AT D13 or D24. Keep the delays on the short side however. The sleds don't coast much better at a higher speed.

Jim

Jim Hinton said:

A really good use for AT 18 mm reloads is for all of those Estes 'Lead Sleds' that Estes recommends a C6-3 for. Rockets like the Mercury Redstone, and Venus Probe which are barely marginal on a C will actually fly real nice on an AT D13 or D24. Keep the delays on the short side however. The sleds don't coast much better at a higher speed.

Jim

Click to expand...

I've got some like that (Alien Space Probe, Deep Space Transport). After fillets, lots of finishing coats and upgrades like longer shock cords, parachutes, they're too heavy for the 18mm BP motors they were originally built for.

Oddly enough, according to the "Estes engine chart", the B6-2 has the greatest maximum lift off weight (4.5 oz), higher than even the C6-3 (4.0 oz). First flight with my Alien Space Probe was to about 80 feet with a B6-2, and the two second delay was just right. Now it gets D10s, D13s, and the like....