See What You Think

Same caveat as the last, not sure how to fine tune and not sure about the results of the sim. Seems like you can have a successful sim under conditions that would never work in the real world...so, I base it the results on faith that it is correct. She's heavy and slow. The Aerotech G was the only thing that I could get a respectable max altitude.

View attachment Valkyrie SAM.rkt

Try checking the weights for both your shock cord and parachute. Both seem to be much too heavy for their size. I don't think that your shock cord weighs 25.0 oz., and I don't think that the parachute weighs 21.9062 oz. either. Remember, garbage in...garbage out.

I made a couple of small changes in your RockSim file. I corrected the shock cord and the parachute. This should give you better results.

View attachment Valkyrie SAM fixed.rkt

a few comments. I would go with 3/32" balsa for all the 'fins', if the lower airframe is based on a bt70 then your tube size is off...otherwise your transition (upper/lower airframe) should be adjusted to match. I question the use of an engine block for a 29mm motor mount.
I ran a sim using the 'fixed' design, F20 took it to 1290'
rex

Rex R said:

a few comments. I would go with 3/32" balsa for all the 'fins', if the lower airframe is based on a bt70 then your tube size is off...otherwise your transition (upper/lower airframe) should be adjusted to match. I question the use of an engine block for a 29mm motor mount.
I ran a sim using the 'fixed' design, F20 took it to 1290'
rex

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Rex and Mike,

Thanks for the input! I wondered about the tube sizes, I've been using the drop downs from the data base and have often wondered if I had to fine-tune the dimensions or not. Last night (while watching KU lose) I was playing around with with another design with a three motor cluster and I noticed from the rear perspective that the tube walls appeared way too thick. I have figured out the fin thickness (lat night as a matter of fact) and like the tube walls, I'd assumed that these things were automatically taken into account. (what I get for assuming) I really need to sit down and watch the tutorials, but for now, I really only have a few opportunities to play with it. You also answered my question about if the sim takes into account build flaws and missing or too many components and whether or not it will run a sim and indicate a successful flight. Apparently, it will. Again, thanks for taking the time to look at it and providing a critique. I can assure you, it has been very helpful.


Steve

rocsim is a good tool, but like most tools one has to keep an eye on it . for reference bt70 is 2.217" o.d., 2.175" i.d., wall thickness 0.021". the engine block would be a bit more usefull if it actually came close to the engine (I'm guessing that was rocsim being 'helpfull'). nice looking design btw.
rex
edit
my 'adjusted' version coming shortly

View attachment Valkyrie SAM_tweek.rkt

Rex R said:

the engine block would be a bit more usefull if it actually came close to the engine (I'm guessing that was rocsim being 'helpfull'). nice

Click to expand...

More than likely, it was me not paying close attention. I'll admit, at this point, I tend to "slap" these together and relying on the software to do the rest. It's obvious that I have a ways to go before I have a truly viable designed rocket. The good news is, I can load them onto here, get some input...at least, as long as you guys will put up with me and my rockets.

it is a good design just needed a bit of refinment...I once tried upscaling a 'zoom broom' to a 32" dia tube...simmed out to 200', on an N5800! decided I needed to get more experience with larger stuff before trying that again .
heh, after putting it on a diet*...I got curious and just for grins I swapped out the motor mount for a 24mm mount 1200' on an F24 .
*took out the plastic nose for balsa...changed the c-rings from 38mm down to 25mm, got it down to 205g w/o motor.

Yeah, I do need to play with the program more too and get A LOT more experience. I have OR as well. I guess what I need to do is have a cheat sheet of tube and parts dimensions so that I can check them against the default parts in the drop downs. I'll get the hang of it here pretty soon. Thanks again for all your help. I truly do appreciate it.

Steve

I've been using a well thumbed 1974 estes catalog...however semroc does have a handy 'print this page' feature on their catalog listings, so one could print out reference pages(which would come in handy to see which nose cones are readily availible ).
rex