VTX Rotorblades - Aero Engineering

[Rpotter90]

Originally Posted by XFC8800

I went through the hole thread before posting this, i couldn't find any answer on my question.

Im building an SAB Uruaky (3 Blades Version), and wanted to run 3x VTX 717 on it, i saw that is has been stated 3 Bladed Heads have not been considered in production/development, therefore i'm asking if it will cause massive issues or not working at all i'm a little insecured from all this info now.

Is there also any status on the 607's ?`

Best Regards
Chris

Originally Posted by VTX Designs

Hello Chris,

VTX 717's have a ton of blade area compared to other 700mm class blades. I think 3 of these on a 10 pound heli would be way too light in terms of blade loading.

I'd suggest VTX697's for this. The 717 is just way too much area.

UPDATE: VTX just notified me they want the 607 main blade design finished. So I'll get working on that soon.

Bill.

JUST came here to ask the same question! Glad I looked back a bit!

[prototype3a]

I ran 3x VTX 697 on a heli blade test rig using the Align head but I never ran them up to "3d" headspeeds as I was more interested in using them for heavy lift "drone" use.

I can say, I did see some interesting trends on them compared to more traditional blades.

FWIW, the Align 3 blade head is essentially rigid and had some really weird vibration issues whenever you gave it any sort of cyclic input making it unsuitable for aerial videography. I remember looking at the Goblin 3 blade head design but I can't remember what if any conclusion I had were. I have been waiting for MSH to release their 3 blade head as I suspect it will actually fly properly.

[Raptorapture]

Originally Posted by prototype3a

I ran 3x VTX 697 on a heli blade test rig using the Align head but I never ran them up to "3d" headspeeds as I was more interested in using them for heavy lift "drone" use.

I can say, I did see some interesting trends on them compared to more traditional blades.

FWIW, the Align 3 blade head is essentially rigid and had some really weird vibration issues whenever you gave it any sort of cyclic input making it unsuitable for aerial videography. I remember looking at the Goblin 3 blade head design but I can't remember what if any conclusion I had were. I have been waiting for MSH to release their 3 blade head as I suspect it will actually fly properly.

I'd check out the Triabolo if you're looking for a smooth running design. It goes up to 800mm blades. I think the minicopter line is being used by others than RC enthusiasts, possibly aerial photography. Though I'm not sure if anyone has put VTX blades on yet. Tempted to myself

[Johnny31297]

Originally Posted by prototype3a

I ran 3x VTX 697 on a heli blade test rig using the Align head but I never ran them up to "3d" headspeeds as I was more interested in using them for heavy lift "drone" use.

I can say, I did see some interesting trends on them compared to more traditional blades.

FWIW, the Align 3 blade head is essentially rigid and had some really weird vibration issues whenever you gave it any sort of cyclic input making it unsuitable for aerial videography. I remember looking at the Goblin 3 blade head design but I can't remember what if any conclusion I had were. I have been waiting for MSH to release their 3 blade head as I suspect it will actually fly properly.

Did you match and balance the three blades against each other? CG and weight have to be identical, otherwise you will inevitably run into vibrations.

[prototype3a]

No, Johnny. I purposely weighted them to force the head to vibrate.

Yes, I'm aware of the Triabolo and a friend has a Vapor 35. I'm not interested in the Triabolo since I wasn't able to get anyone to talk to me about it as a platform since I suspect Pulse Aerospace has some sort of exclusivity deal.

[msallua]

Very interested thread! Congratulations to the team ..
It's time to try set

I'm a hard 3D flyer ...

It's time to try a set in this two helicopters:

1) Goblin 700C 2250 rpm
2) Align 700N DFC 2000 rpm


Team, can you give me some advice ..

Size of the VTX blades for G700C?
Size of the VTX blades for Align 700N DFC?

TIA

[xcellfury]

VTX 697mm would be the way to go for both helis.

[Joe90]

Hi Mr Wightman,

I am working on a endurance setup for a UAV aerial photography
Can you recommend a optimal (low power/enough control authority and lift margin of 1G) hovering pitch ?

I was thinking of 7 degres of static pitch and 14 degres for max pitch coupled with 6 degres of cyclic. Will adjust rpm to match.

What are your though ?

AUW would be 4.1kg using 557 blades for now.
waiting for 607 blades.

Regards

[VTX Designs]

Originally Posted by Sneeky_Pete

Wow, I'm pretty sure this is the first time I have read through a thread from start to finish!

Bill, thanks for the time and effort you have put into both the thread and your designs!

Do you have a ball-park time frame on a 517 blade, because there's a pair with my name on them!

Cheers,

Pete

Hello Pete - I'm sorry, but as of now I haven't received any word on the 517mm main blades. We have talked about doing this size before - I think it was last year some time - but for now its not a front burner project.

Originally Posted by Joe90

Hi Mr Wightman,

I am working on a endurance setup for a UAV aerial photography
Can you recommend a optimal (low power/enough control authority and lift margin of 1G) hovering pitch ?

I was thinking of 7 degres of static pitch and 14 degres for max pitch coupled with 6 degres of cyclic. Will adjust rpm to match.

What are your though ?

AUW would be 4.1kg using 557 blades for now.
waiting for 607 blades.

Regards

Hey Joe - your question is pretty deep. All I can do here is give you some pointers - so here are a couple things to consider:

For a sustained hover situation, its important to operate the blade efficiently in (2) significant ways:
1) Angle of attack - "AOA" must be controlled so as to run as close to design max L/D as possible. Your intuition of 7 degrees is darn close to that point for most typical airfoils. Keep in mind that when running flat, symmetric blades we have a massive AOA spread across the rotor span. For this reason, I highly recommend tailoring the blade using twist,camber and chord length to maximize L/D across blade span and to better control the inflow field. And of course we also must keep tip speed under control to avoid compressibility losses.
And 2) we also must keep in mind that AOA is measured as the angle between the "relative wind" (RW) and the nominal chord line for the airfoil. AOA isn't equal to physical pitch angle. So in this case, simply using physical blade pitch for AOA would be incorrect because of RW changes induced by flight path vector, and inflow field velocity (and to a much lesser degree flap motion). Inflow velocity begins to play a major role in sustained hover because as inflow speeds increase, blade pitch must also increase to keep AOA where it needs to be for lift to offset weight. And, as physical pitch increases the lift vector is tilted backward (relative to the shaft axis), so we experience a loss in effective lift; and a corresponding increase in aerodynamic drag. These lift loss/drag increase factors track a cosine function of pitch angle if I remember correctly...
So, for the most efficient sustained hover we want to keep inflow velocity low, and blade AOA under control. This mission requirement calls for more overall disc area with blade area matched to flying weight and power available. The more disc area we have, the lower the inflow speeds will be and we'll be making lift more efficiently. Spinning shorter blades faster like a tail blade system, three blade head, or running coaxial configurations both drive effective disc area down, which moves us toward higher inflow speeds and those cosine losses mentioned earlier.

Best wishes,
Bill.

[JWeber]

Been pretty quiet here. Anything new in the works?

[Maldeen]

What about 107's tails...?

[mr. mark]

Originally Posted by Maldeen

What about 107's tails...?

i believe that project is still on hold

[Maldeen]

Originally Posted by mr. mark

i believe that project is still on hold

Why?

[mr. mark]

Long story, https://www.helifreak.com/showthread...776615?page=13

[EastCoastFlyer]

Same question came up on FB. If i remember correctly Kyle Dahl was doing some testing and found that the blades have really bad characteristics above 11k rpm. All the initial testing was done with the tail between 8k and 10k and thats where the good results came from.

[tacomaster]

Originally Posted by tacomaster

477 question. Are these biased for positive pitch? I zero’d my grips and the blade reads 1.5. Even doubled checked the grip zero with Allen wrench method. In flight it had more positive pull. Guess I’ll fix the throw with the blade grip links lol

Forgot to update this. It was the grip machined off. No issues with the blades

[smittylube]

I love to tinker and before my logos I had a trex500 original first release. It then became FBL with the mini vbar and I call it my VRex.
Since my logos get most of my attention and the Trex isn't worth anything to resell, I decided to stretch it to accept the leftover edge 473's I had been running before stretching my 480 to run 520's..

I found some pipe to make a boom, an arrow shaft to jb weld a cut torque tube. Poof a VRex 500 that now flies 480 blades. Weighs about 4 1/4 lbs +or- depending on packs and canopy or not.

Well the edge blades flew excellent, but I had to try the VTX... They weigh a bit more like 8/10 gr more each, but OMG how nice do they fly?
It's been really windy the times I've taken it out and it doesn't bobble and flies amazing. Autos like a champ! Blasts around with authority at full speed (for me) without any weird pitchy behavior that I notice. They might roll a tad bit slower than the edge, but they make up for it all with overall handling like its on rails. Locks into hovers right side up or inverted even in the high wind with almost no bounce. Plus they look pretty cool IMO.

Very impressed with these blades. Great job VTX guys. Thanks for an excellent product.

It's crazy how something so old can fly so well with 5.3 pro and some great blades.

[jackhsu]

This is absolutely the most informative thread I've ever read. It's great fun to go through the whole thread. Thanks Bill.

[anthony1]

i'm sure this has been answered in this thread but i can't find it , too much information,

do i need harder or softer dampening for a logo 480 (stock) using vtx blades?
Anthony

[VTX Designs]

Thank you JackHSU. Nice to hear the feedback.


Smitty - cool to hear how the 477s did. They're my personal favorite blade product (being an engineering geek).



Everybody: I haven't finished the 607. Bryan has been off line - total silence. There are issues involved that will require an actual VTX officer to solve. Thats not me. I don't have answers, unfortunately and am still constrained by NDA otherwise. I am sorry.



Bill.