VXV

July 24, 2017:

EARLY WRAP UP: Yes, after just one speed run (161.1 mph and 100m opposite direction average of 157.7 mph on 5s), big breakthroughs in frame design has caused me to put all efforts toward project VXR-190 which should be good to go next week (I still might make a flight or 2 more with the VXV).

VXV 19

Contents:

  1. VXV: The “Velocity” Derivative of the VX1
  2. Documentation of Data
  3. All About the Props
  4. Electronics
  5. Frame Bill of Materials
  6. Photos
  7. Results

VXV: The “Velocity” Derivative of the VX1

The frame will end up being nearly twice as heavy as the VX1, but it will be well worth it. The goal is to have a very durable and efficient all around flyer that can attain speeds of 180-190mph with a 5s lipo. I always feel way off on the speeds on these projects, but calculations have been very accurate so far and actually put this build at 190+ mph! However, I like to keep predictions conservative.

After all the research, I was able to see how the VX1 was capable of reaching speeds near theoretical prop pitch speed:

  • Low drag coefficient = less torque required to fight drag
  • Low drag coefficient = more torque for RPMs
  • Careful balance between motor kv, prop diameter, and voltage kept prop tips from entering transonic speeds (very important!)

Keeping with the same ideas, drag will be further reduced on the VXV and prop pitch will be increased to 6.

Differences from the VX1:

  • DYS fire motors Cobra Champion 2207 2450kv motors
  • Spedix HV 30a ESCs
  • 6s capable 5s lipo (click here for more info on this choice)
  • 8mm motor arms 10mm arms reinforced at weak points with 8mm and 12mm carbon fiber tubes
  • Use of solid copper wiring for clearance issues (between ESCs)
  • More streamlined body
  • Thicker walled carbon fiber body tube
  • Longer body to increase  strength around arm holes
  • Longer arms to accommodate APC 5.2 x 6.0 props

Documentation of Data

This time around, I will be addressing another goal I wish I had done with the VX1: video of the frame being fitted with the 5s lipo, flown, and landing (or crashing). Osd video should be much better this time too. Again I will use GPS for recording speeds and distances flown. Much more info will be presented and dissected.

VXV 03
Base frame

 

VXV 04
12mm CF tube adds strength to arms at shear stress points. 8mm tubing is also on the inside of the arm.

 

 

VXV 05
Epoxy reinforcement

 

VXV 06
Motor mount holes – looks weak but never had one break or crack

 

VXV 07
Quite a bit heavier than the VX1
VXV 08
2 inch R/C airplane spinners for front and back

 

VXV 09
Spinners add even more weight

 

VXV 11

 

VXV 12

VXV 10

VXV 14
Last second choice to put the GPS in the nose cone, not in the top of the body tube as originally planned

VXV 13

VXV 16
Don’t forget to put on the signal wires like I did…

VXV 15

VXV 17

VXV 18

VXV 22

Once again I went with Cobra 2207 2450kv motors from Prop Shop

 

VXV 19

Results

So far, only on flight day with speed runs. Tuning is still subpar, but I gave it a go anyway. Not posting any super-in-depth analysis yet since I am not done pushing this frame.

  • 4s lipo: 131.5 mph opposite direction over 100m, 135.9 mph max
  • 5s lipo: 157.7 mph opposite direction over 100m, 161.1 mph max
  • 6s lipo: Cancelled to begin work on the VXR
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s