Whirlwind Prop Test

[SuberAvid 617]

JackAk took the plunge and bought a set of the Whilwind Scimitar blades for his warp drive hub. These are a 3 blade, 70" setup. Since Jack's bird isnt flying yet and we couldn't wait to try them, we had to use SuberAvid as a test bed. I have about 2.5 hours on it at 17 and 18.5 degree pitch settings. Due to the shape of the blades, they furnish a slick little tool that slides over the blade until it snugs tight about in the middle of the blade so the readings are at the center of the blade, not at the tip.

Here are my initial observations: In the looks department it is by far the prettiest prop out there; the front is shiny carbon fiber with a perfect inlaid leading edge and white tip paint and the back is dulled to a satin finish. The prop is smoother running than both my Warp Drive and IVO. At 17 degrees it climbes out at 4800, the same rpm I get at the flattest pitch on my IVO. I runs very smooth but speed is about 70 mph at 4000 rpm cruise. At 18.5 degrees climb out is at 4600 rpm, still climbs very strong and runs smooth. Climb outseems to be as good as my 72" IVO; about 800 FPM. At 4000 rpm cruise it is doing around 75+ mph.

I am going to try it today if I can and plan to try 20 and 21.5 degrees. Attached are some pics, the first is my IVO, the rest are the Whirlwind (pretty obvious)

[EDMO 1078]

Randy,

I am very interested in whatever you get on the Whirlwind tests - But thought earlier that you were only getting about 3800 rpm - not 4800 on your Stratus??

On 650 hour inspections for these blades - Do they have to be sent back to factory?

Good Flying,

ED in MO

[C5Engineer 1170]

That is purty!

[SuberAvid 617]

JackAk took the plunge and bought a set of the Whilwind Scimitar blades for his warp drive hub. These are a 3 blade, 70" setup. Since Jack's bird isnt flying yet and we couldn't wait to try them, we had to use SuberAvid as a test bed. I have about 2.5 hours on it at 17 and 18.5 degree pitch settings. Due to the shape of the blades, they furnish a slick little tool that slides over the blade until it snugs tight about in the middle of the blade so the readings are at the center of the blade, not at the tip.

Here are my initial observations: In the looks department it is by far the prettiest prop out there; the front is shiny carbon fiber with a perfect inlaid leading edge and white tip paint and the back is dulled to a satin finish. The prop is smoother running than both my Warp Drive and IVO. At 17 degrees it climbes out at 4800, the same rpm I get at the flattest pitch on my IVO. I runs very smooth but speed is about 70 mph at 4000 rpm cruise. At 18.5 degrees climb out is at 4600 rpm, still climbs very strong and runs smooth. Climb outseems to be as good as my 72" IVO; about 800 FPM. At 4000 rpm cruise it is doing around 75+ mph.

I am going to try it today if I can and plan to try 20 and 21.5 degrees. Attached are some pics, the first is my IVO, the rest are the Whirlwind (pretty obvious)

I put a couple more hours on the Whilwind prop today. I set it to 20 degrees and it started to get where I thought it should be. The takoff RPM was about 4400 with still a strong climb. Cruise was about 80 mph at 4000 rpm and 75 mph at 3750 rpm. I then changed it

to 22 degrees and I think that is about the sweet spot for the Subaru. Take off was 4250 rpm with a 650 to 700 FPM climb. Take off run in about 4"to 6" of untracked snow on top of old snow, was around 300 to 400' (estimated not measured). Cruise was about 88+ mph at 4000 rpm and about 84+ mph at 3800 rpm burning right at 4 gph.

Yesterday I was not as impressed with the prop, it seemed slighlty better than the Warp Drive and not really very close to the performance of the IVO IFA. Today with the prop set at 22 degrees, it really is impressive and is noticably better than the Warp Drive on both the low end and high end. It doesn't beat the IVO IFA, there is just no substitute for the advantage of the IFA, but if I ever had to go back to a ground adjustable prop, this would be it. I makes up half the difference between the Warp Drive and the IVO IFA.

Ed, I am not aware of the hour limit on the blades, Jack may know. They do warn against over reving the blades; I think it was 2500 rpm at the prop. My Stratus will do 4800 on climbout with the pitch set flat but it does not seem to want to go to 5200. It really runs well at the 3700 to 3800 rpm range for cruise and will do 95 mph there with the IVO no problem. I think that is just where it is reaching its peak torque.

[EDMO 1078]

I put a couple more hours on the Whilwind prop today. I set it to 20 degrees and it started to get where I thought it should be. The takoff RPM was about 4400 with still a strong climb. Cruise was about 80 mph at 4000 rpm and 75 mph at 3750 rpm. I then changed it

to 22 degrees and I think that is about the sweet spot for the Subaru. Take off was 4250 rpm with a 650 to 700 FPM climb. Take off run in about 4"to 6" of untracked snow on top of old snow, was around 300 to 400' (estimated not measured). Cruise was about 88+ mph at 4000 rpm and about 84+ mph at 3800 rpm burning right at 4 gph.

Yesterday I was not as impressed with the prop, it seemed slighlty better than the Warp Drive and not really very close to the performance of the IVO IFA. Today with the prop set at 22 degrees, it really is impressive and is noticably better than the Warp Drive on both the low end and high end. It doesn't beat the IVO IFA, there is just no substitute for the advantage of the IFA, but if I ever had to go back to a ground adjustable prop, this would be it. I makes up half the difference between the Warp Drive and the IVO IFA.

Ed, I am not aware of the hour limit on the blades, Jack may know. They do warn against over reving the blades; I think it was 2500 rpm at the prop. My Stratus will do 4800 on climbout with the pitch set flat but it does not seem to want to go to 5200. It really runs well at the 3700 to 3800 rpm range for cruise and will do 95 mph there with the IVO no problem. I think that is just where it is reaching its peak torque.

Randy, Glad to hear the new results on the prop - The guy who sold me the Soob said to set it at 42 or 4400 static, but not sure he knew much since he only had 25 or 75 hours on it.

I think I got the 650 hour inspection on the blades from the Whirlwind site - cant remember any where else that I might have found it.

ED in MO

Edited 19 Feb 2013 by Ed In Missouri

[jackak 20]

Randy, Glad to hear the new results on the prop - The guy who sold me the Soob said to set it at 42 or 4400 static, but not sure he knew much since he only had 25 or 75 hours on it.

I think I got the 650 hour inspection on the blades from the Whirlwind site - cant remember any where else that I might have found it.

ED in MO

Ed,

I checked the manual that came with the prop and couldn't find a requirement for a 650 hour inspection. They talk about the first 50 hour inspection and then the annual inspections after that, but the only time you might have to send the prop back to Whirlwind is when it failed one of the inspection criteria.

I'm sure glad Randy was willing to do the flight tests and do the comparison between the Warp drive, the Ivo and the warp hub with the Whirlwind blades.

Jackak

[EDMO 1078]

Ed,

I checked the manual that came with the prop and couldn't find a requirement for a 650 hour inspection. They talk about the first 50 hour inspection and then the annual inspections after that, but the only time you might have to send the prop back to Whirlwind is when it failed one of the inspection criteria.

I'm sure glad Randy was willing to do the flight tests and do the comparison between the Warp drive, the Ivo and the warp hub with the Whirlwind blades.

Jackak

Thanks to both of you for the info - Did you specify the diameter, or is this standard? Seems like I read the standard blade length, but site said it could be shortened - Am I remembering 63 inch blades standard without hub?

I was wondering about going to 72" diameter.

ED in MO

[jackak 20]

Thanks to both of you for the info - Did you specify the diameter, or is this standard? Seems like I read the standard blade length, but site said it could be shortened - Am I remembering 63 inch blades standard without hub?

I was wondering about going to 72" diameter.

ED in MO

Ed,

When I called Whirlwind, we discussed the engine that the blades would be used on & it was recommended that with the 100hp Subaru that I get the same blades that are used on the 914 Rotax. They are stronger than those used on the 912. The blade length is 33" and can be shortened a small amount. I don't have the manual with me right now but the amount you suggested seems to be the stated amount the blades can be shortened. With the 33" blades the prop diameter is right at 70". I wasn't offered the choice of 72" diameter with the 914 blades, but if that's what you want they may be able to fix you up. One of the advantages in dealing with the manufacturer. They're great people to deal with too.

All the best,

Jackak

[jackak 20]

Thanks to both of you for the info - Did you specify the diameter, or is this standard? Seems like I read the standard blade length, but site said it could be shortened - Am I remembering 63 inch blades standard without hub?

I was wondering about going to 72" diameter.

ED in MO

Ed,

I think the 650 hr. inspection you were wondering about has to do with the variable pitch prop that some people are using on the Van's aircraft with the Lycomings.

Jackak

[EDMO 1078]

Ed,

I think the 650 hr. inspection you were wondering about has to do with the variable pitch prop that some people are using on the Van's aircraft with the Lycomings.

Jackak

Thanks again for the info - I had probably better go with the 70, since my HP is only 80-85 unless I redo the cam.

Someday I will call them.

ED in MO