Sport Copter Vortex 618

[Rattler 1]

Can anyone give me the realistic cruise speed on a Vortex with a 618? Mine cruises at about 60 mph at 6000 rpm. I have an E gearbox with a 3.0 to 1 ratio. Has a Powerfin Prop. I have a max rpm of 6500 in the air but fly at 6000. At this RPM I burn exactly 5 gph. Just need a ballpark so I know I'm somewhat close.

Thanks.

 

[Jazzenjohn]

That seems a bit low to me. What diameter prop and how many blades do you have? Do you have the pod/windscreen on it? You can get a little better cruise by setting the pitch a little higher with a small sacrifice to climb performance. you could try setting the static rpm on the ground to say 6100- 6200 RPM and check the difference.

 

[Rattler 1]

Silly but I need to check the prop diameter. I should know that. It's a 3 blade powerfin. I do have the partial enclosure on it with full windshield.

 

[Rattler 1]

I did a bunch of testing today. The engine is a 618, gearbox is a 3-1 ratio, I have a 66" Powerfin. Static pull at 6100 rpm was 326 LBS. I changed pitch to max static RPM at 6900 rpm with the same amount of pull. 340 LBS. I reset it to 6100 rpm as in the air I got 6500 rpm.
My ground speed at 6500 RPM was about 68 MPH. Throttling back to 6100 gets me 60 MPH.
Outside temp was about 68 deg. and am at 1200 ft above sea level.

Can someone with a Vortex 582 tell me what they are getting? I do have the full windshield partial enclosure. Also larger tires.

 

[BEN S]

Hmm...sorry, Mine goes from here to right about there before take off unless the winds are over 15, the it takes off right about yonder.
It seems to hover mostly in the green with some yellow, but I move the stick thing to make sure it never goes in the red....
When my trailer is built and I can fly again, I will see about getting you some numbers.
Currently I am grounded.

 

[Rattler 1]

Well that's one reply. Not sure how accurate but I'll see if mine is the same.

 

[Kevin_Richey]

Hmm...sorry, Mine goes from here to right about there before take off unless the winds are over 15, the it takes off right about yonder.
It seems to hover mostly in the green with some yellow, but I move the stick thing to make sure it never goes in the red....

 

[Jazzenjohn]

66" seems quite small a prop diameter for a 3-1 gearbox. I'd expect to find a 2.62 gearbox and a 68" or bigger 3 blade prop on something like that.

 

[Rattler 1]

Yesterday I installed 2.62 gears on my Sport Copter Vortex 618. I pitched the prop to about 11 deg. The prop is a powerfin 66 inch. I know a 68 inch would be better but for now that's what I have. The outside temp was about 85 deg and my altitude on the ground is 1200 ft. With the prop set at this deg I did a pull test. I got 340 lbs with a high idle of 6100. Test flying It I got about 65 mph full throttle. In the air it can reach 6300 rpm. I would like to see it fly faster but am hopeful it goes to at least 70 in cooler temps.
It seemed to fly much better with these gears as apposed to the 3-1 before. Could keep the speed up much better. Before it was mushy in hot weather.
With the pull test I use a factor of 2.05 to figure out the HP. 340 lbs divided by 2.05 is 69.7. I'm sure in the air and in cooler weather its hitting the 75 hp the engine puts out.
Any other Sport Copter guys here that can confirm I'm about right in performance? I know its advertised to go 80 but that's at sea level and probably cooler weather. FYI, I used GPS to confirm air speed. Flying in two opposite directions and averaging out the speed.

 

[Jazzenjohn]

2 or 3 blade prop? Your setting of 6100 static is a bit lower than the full power rating RPM of 6750 (I think). You might try playing around with the pitch a bit more. Generally you'll get a bit more speed with a 2 blade prop vs. 3. Have you fixed your rave valves?

 

[Rattler 1]

2 or 3 blade prop? Your setting of 6100 static is a bit lower than the full power rating RPM of 6750 (I think). You might try playing around with the pitch a bit more. Generally you'll get a bit more speed with a 2 blade prop vs. 3. Have you fixed your rave valves?

I have my RAVE valves shimmed wide open so to ensure full power at high rpm. The prop is a 3 blade and I do have the partial enclosure.

 

[Rattler 1]

Well I took my RAVE valves out. They were stuck pretty good. I removed all the washers I had installed to hold them open. I did find some washers that someone installed on the stem between the housing and the valve. This held them from opening all the way. I removed them also. I also replaced one diaphragm. I drilled a small hole in the diaphragm piston right on top of the 10 mm nut. I epoxied a small rivet shaft in the hole so it stuck straight out. I drilled a slightly larger hole than the rivet shaft in the red plastic adjusting nut. This is my indicator of the rave valves working. While flying, when I reach aprox 5800 rpm, the shaft starts being pushed out. The more RPM the further it sticks out. Now I can see if their working on the fly.
Now the results in the air. I was getting 6500 rpm full throttle in the air. About 60-65 mph. After rebuilding, removing all the washers and cleaning, full throttle went to about 7100. I added a couple of degrees to the prop so full throttle rpm is now about 6800. Full throttle I now get about 73 mph. When throttled back to 6100 it goes 60 mph. I also tested the fuel burn at 6100 rpm and it was about 5 1/2 gal per hour. Not bad. It now performs as expected. I was wrong by shimming the rave valves open. But I also found out that they were not completely open because of the other washers between the housing and the valve. I did not see this until they were completely removed. It as a great day today.