Baffle

I have a baffle question for you folks out there. I been sport flying since '74 but always with wadding, and nothing over a "E". I'm building a new model that will take up to an "E" and have decided to try a bafle in place of the wadding. Basically it's 3 oval disks each having offset holes that I've epoxied into a tube coupler. My question is this I'm thinking it should go down near the engine mount as it is easier to add clay to the nose if the CG is off. Is there a minimum distance I should keep from the top of the engine? Any thoughts on this?

Reply to
mkpainter
Loading thread data ...

See the article in my .sig for a proven baffle design...

The key thing to remember about baffles: it's NOT the hot gasses that burn chutes. It's the burning particles. A baffle functions as a darkroom light trap, stopping the particles, and allowing hte gasses to pass through.

My rule of thumb for baffles it to preserve the MMT area through the ports. if you have a 24mm (1") motor, then 4 1/2" holes or 16 1/4" holes provide the same vent area.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

Bob, Thanks for the input. I actually saw a similar design on another website (I'm sure the guy got it from you). The rocket I'm building, I believe, will be a tad too small diameter wise for that design. Which is why I went with the 3 oval disks(design I got off of Mad Rockets web page for smaller diameter tubes.). I know I need to stop the hot particles, I'm just wondering how close I can get it to the motor. Basically, I'm kit bashing an old Estes Maniac. I'd like to have it close to the MMT if not right on top. I'm just wondering if the ejection charge won't FUBAR the end of the rocket. I certainly appreciate your comments though. I plan on building a larger rocket later, and I already printed a copy of your baffle design the other day and have it stashed with that kit.

Thanks Again

Mark Painter

formatting link

Reply to
mkpainter

Define "too small". I've implemented this in a BT-50 rocket with an 18mm MMT. But in general, I don't really recommend it for rockets smaller than BT-60.

For the Maniac / Eliminator, I'd make the whole first section of tube the baffle section, from just above the motor mount to the coupler. In fact, I'd use the coupler as the mounting plate for 2 of the rings, as well as the anchor for the shock cord. You've got plenty of space, so don't worry about sticking the first baffle plate right on top of the MMT. Do coat the motor side of that first plate with some epoxy resin to prolong its life.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I'm using a BT-55.

Actually that was exactly what I was thinking. as a matter of fact, I was planning to place the first ring in the tube that serves as the motor block, with the remaining 2 rings in the main tube itself, with all 3 about 1/2 inch apart ( Too Close?). As to the epoxy resin, I coated the first two rings. I figured they would need it. So, you don't think having the ring right on top of the MMT will cause any problems?

formatting link

Reply to
mkpainter

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.