15 m/s or more generally, particularly if there is wind. I never go below 10 m/s.Hi Folks,
I'm simming a collection of mid power rockets of interest, and while OR hasn't given me any warnings yet, how slow is too slow when looking at velocity off the rod?
5 m/s? 6 m/s? etc.
If I was launching a small low power rocket, then maybe I would be comfortable at 10 m/s, or lower. It's a very long time since I launched low power though. However, since I mostly launch mid and high power rockets, I prefer 15 m/s as a minimum.But you would be comfortable launching at 10m/s in no wind?
I've done this very often with long BT60-70 rockets without ever an issue, so the 15m/s goal surprised me.
I guess a difference with park/farm flying is you only head out when the wind is low, rather than needing to build for flight days, come what may.
Also, now that I think about it, our long LP scratch builds with their acrylic payload bays and heavish payloads would have a much greater polar moment of inertia than typical kits, I just never considered it.
The Estes 2.5" PS II kits after dropping composite motors called for F15-4 only. I've flown F15-6's in rockets up to a pound unloaded and the ejection is very late and I finally broke a shock cord. Unfortunately the only F15-4's I've acquired were from Estes Warranty service. Fun motor with lots of smoke etc. even if altitude is low. The only way a single F15-6 would work for 500g is if it was all mass no drag.According to the Estes description of their F15-6 motor, they say the maximum recommended liftoff weight is 17oz, or 482 grams. That should include the weight of the motor too. The motor is 3.66 ounces, so the rocket should probably be closer to 13oz. I think they are probably using a more generous thrust to weight ratio than a more cautious person would recommend. So most likely you should be looking for rockets that are around 11 or 12 ounces, so maybe 300 to 350 grams. Maybe a bit more under great conditions with a long rail.
Here’s the motor page. Check the technical description. https://estesrockets.com/product/001652-f15-6-engines-29-mm/
I'm simming for F15 motors, as I like a long burn I can see. By switching to a 12' rail I'm getting 40f/s. (500g, 2.6" rocket.)
What wind speed is that fine below?
I'm surprised there isn't more readily available data around for this. Wind speed meters (anemometers) are quite cheap, it would make sense to me to be able to know your preferred combo is good up to X wind speed, rather than an all or nothing approach.