$21.00 to the door, kinda makes the mods I developed unnecessary, tho parts will eventually dry up for a discontinued model…
I don’t think it’s unnecessary. Look at the Karearea frames. They have the same configuration using struts front to rear. Reviewers claim a more precise feel in turns and flips. Would like to hear your impressions when you fly this new frame and then add the struts to see if you detect a difference.
I will be creating the struts like you did. Where did you get the CF tubing?
Aloha! Yes, I’m not tossing them. They are the smallest pultruded cf in the Rock West Composites web site. They have a location that used to be within range of my house…
…sorry, no spec but it is the smallest hollow tubing in their catalog, pultruded and cheap. The string mod is actually more important, much more effective at thrust line alignment, and will come into play as the poly ages. Luck! se
IIRC the original DJI Phantom had a string tensioner going around the outside of its span.
Aloha!
I had to come back to this subject, Dude! The Spectra string (important, zero stretch) harness was created to line up the thrust angles on the sagging frame in order to measure for and build the struts you saw. It became the better brace system.
I built the longitudinal struts before realizing that the frame was now already fully triangulated and as strong and stiff as my 3mm carbon fiber frame! The key is the 3 way swivel, which aligns the pull along the leg, and could easily be duplicated with other hardware or knots.
This brace counteracts the tendency of the legs to sag towards the center with use (thrust lines converge, rolly poly holdy) The struts I designed using the prop guard mounts tend to obstruct the camera and impose a much greater aerodynamic load, IMO.
I’m trying to build an 1106 brushless motor version of the factory frame that will eventually depend on string, I’m sure! In addition to the string, I may use the thin tubing and route the string through it for a clean setup that uses both tension and compression for better strength.
Combine this with the struts to better locate the motors within the thrust plane if using more powerful motors. The full bracing setup may hold up to much more powerful motors that could easily fit atop the gear housing on the stock motor mount. Like 2207s!!
Notice the battery holder mod? Ready for a 12 mm or 15 mm thick lipo (2000+mah) or a 2s pack!
Best Luck, se 
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I wish you could test at 4200’ asl! 
Actually, I think everyone would benefit if people used (or at least had available) the test data for, say, 5000’ asl and 90f as my impression is that many off-the-shelf designs suffer much more performance loss from thin air than most folks realize!
Denver, Reno, Salt Lake,City, many lift served trails, etc…se
You can simulate elevation and air temp in Ecalc for an approximation.
Good point! Build a good formula to convert for altitude. My experience has been that a simple percentage adjustment is inadequate, especially when Reynolds numbers relating to very small props creeps in. These quadcopters have little leeway in terms of thrust to weight ratio, IMO. Especially as this design has evolved and gained weight from the original v2400hd. If you lose 15% thrust performance due to altitude and heat, from where the design was tested, it seems that an off-the-shelf quad can go from efficient to unflyable very quickly! I have found the need to upgrade props just to keep the quad flying at all, although experimenting with props can be expensive! (The motors, not the props) I’m modifying an extra frame to 1106 brushless for this reason and service life!..Luck, se
Take a generic 450 size quad configured for 50% throttle at hover at 256m (where I’m at). It would require 58% throttle at 2926m in Breckenridge, CO where my brother used to live. Holding temp constant.
I remember flying my Solo in Flagstaff, AZ (7200 ft. and 48 degrees F) and a normal 20 minute battery lasted only 8 mins.
4200’ asl and 90f does appear to cause a loss of thrust for this powertrain, which becomes easily observeable f the design is in the lower thrust/weight range, IMO (In My Observations?) The stock setup produces a Learned Hover Throttle Value of 53%, which becomes more significant the moment you add turbulence to the equation.I have to wonder if at “the office” that value is more like 35%? se
Just to add another data point on blades, the Gemfan MCK 51466-3 were a lot like the Wind Dancer 5042’s. The thrust was barely sufficient and the motors will overspin. Thanks for your posts!! They have been a lot of help.
Aloha Kengineer!
Quick recap-
I live at 4400’msl and at 90+f and 15% rh, many oem toy grade are at their limits here.
The Sky Viper is an example.
The Gemfan 5555 3bl bullnose draw too much without dropping to an 11t pinion, then they are much better. Guessing that they would be way too much at sea level. The 5044 Wind dancers, even with a 13t pinion, were still a bit limp. For here, something like the 5555 code red 2-blade by gemfan seem to be the best choice without changing ratio. Also the stock motors… …maybe 14k on a good day.
Simple and cheap upgrades are everywhere (mmw’s are great, crazypony’s are cheap, and you can select rpm). Find the long gear on the pinions due to slop, the bearing upgrade may be the best thing for the 2450! I would try the code reds at sea level as going 3 blade is better left to more powerful brushless applications, imo. Which is why I have gone over to the dark side…
…Here’s an example of my latest experiments. Now that we have access to the DJI f/c…
As you can see, 4 different sets. I’m still working with the Skt Rocket v2450 pcb’s for transplant into a wingsland s6 brushless, brainless, ummm, project(?) tho…
Good Luck! se
Thanks Steve,
The 11t pinion was definitely a great piece of information. I have purchased some Gemfan 6040s and I figured there would be an increase in current draw if i didn’t do something to counter the new load on the motors. I am trying to squeeze a little more flight time out of these batteries at the cost of speed. The Skyviper 2450 gps has been a great first drone, and one where I can experiment and learn before moving on to something bigger (and pricier). I love to tinker, and this drone seems to be one that allows for that at the moment. I’ll probably buy the Journey later this year (maybe they will have more kinks worked out). Eventually I’m looking for a drone with brush-less motors that will still allow me to tweak and play.
Thanks for your posts!!
KB