what are the plus and downsides from a deadcat frame?

sure the camview is free, but in terms of flydynamics? what i beleive, because of near props in the rear , its a benefit for yaw performance. am i wrong, yaw performence is the biggest issue?
on the otherside, on a normal racequad, not on a powerbeast which flew nearly vertical, the air for the rear props have allways more „turbulence“, unclean air. the rear motors have to work harder, near props in the rear does give even more unclean air to the rear props. in 5inch racers is a trend to do the opposid; 6inch arm in the rear and normal 5inch arms in the front. is there a difference in flydynamics which comes in at a specific speed, more clean air improve on a 5inch at high speed, on a micro it doesnt? like more wingspan between front and rear motors improve flydynamics on the pitch axis?

Good question.

The dead cat design has been around for a long time.  But it has had a recent resurgence due to the long range cinematic crowd.  Jordan Temkin came up with a dead cat design with the Project 399 Super G+.  After him, there is the FR7, FR8, FR10, and now even a FR5 and FR3.  The FR series are all open source, but the brain child of Jeremy Mariscal.  There are other dead cat frames out there, but the FR series and the SG+ are the two most popular right now.

I was more interested in how the dynamics of a dead cat might affect efficiency.  But based on what some of the long range guys have found, it doesn't appear to be an issue.  One thing that did come up with the SG+ at its genesis was instability while in steep dives, like down cliff faces, etc.  Guys were setting up in BF as a straight X design.  Once they started setting up as a custom in BF and used the program that Project Blue Falcon explains, the instability went away.

Given what you mention about some of the dynamics of the dead cat, I would think it likely is a bad choice for racing.  It might even be a bad choice for Freestyle.....I don't know.  I do know that it has a very strong following in Long Range.  But who knows what the next frame idea will be.....only time will tell.

I sure love how my SG+ flies right off the build bench.  It is the smoothest, most sorted out quad I've ever flown at this point.  Maybe after a few flights warts will start to appear.  But I'm not really expecting it.  If there are issues, I will certainly report back to the forum.

because of your buildlog about your 399 super g+, the question start to bother me. i cant find the propsize? i guess its 7inch?
what i mention about, the theory doesnt realy affect to yours, because even with deadcat the rear props arent near to eachother,i beleive the „unclean air problematics“ wouldnt come more frome the deadcat design. i beleive for longrange, wide wingspan give stability and will cost agility, but result in efficiency aswell. a flybuddy own a longrange 7inch and use it for freestyle aswell, he has a unusual 7“ frame with near props, a true x. i guess the ability for freestyle come from the small wingspan.

i have a long relationship with „diatone grashopper 160“ a 4inch deadcatframe, with very close props in the rear. its a very old framedesign, i guess from 2015. i like the flydynamics, how nimble it is. i flew it with a lot of diffrent settups; motors, props. i dont feel downsides, but i like to know what i probably cant feel?