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whirlwind 74RV in taildragger?

D

DAS

Member
was talking to the guys at whirlwind, and they have new prob called 74RV, which is 74inches, would this be a problem on a taildragger?

my interp of the info on vans site is that the 72 inch is rec for this application.

thought from the group?

das
 
What model plane? On my RV8 I have 72" and can't imagine one more inch making much difference as there is plenty of ground clearance.
 
No problem at all with the 74RV in an RV-8 taildragger. I originally had the 200RV 72" blades and swapped to the 74RV, no complaints.
 
Whirlwind 72" vs the 74"rv

DAS said:
was talking to the guys at whirlwind, and they have new prob called 74RV, which is 74inches, would this be a problem on a taildragger?

my interp of the info on vans site is that the 72 inch is rec for this application.

thought from the group?

das
Click to expand...

Any performance comparisons between these two props - actual or hearsay?
 
OGee said:
Any performance comparisons between these two props - actual or hearsay?
Click to expand...

I've had both the 200RV and 74RV on my IO-375 powered RV-8. I haven't done any credible performance comparisons, but gut feel is that performance is generally similar, 74RV seems to accelerate, climb and slow down better, 200RV might have a slight edge in cruise speed.

The 74RV looks faster on the ground and gets a lot more attention than the 200RV did.
 
Hartzell v. 74RV

I changed from a 72" Hartzell BA to a 74RV at 75 hours on a IO-375 mounted on a -7. I was concerned about vibration effects on an aluminum club from a ~210hp engine with EI, 9.6:1 compression. What performance comparisons I made did not show detectable, repeatable results between the two. My butt tells me the 74RV is a bit smoother. Prop looks a lot faster than what you'll experience. Don't sweat the inch radius on a TD unless you try to "pin" a botched wheelie. I know a guy who trimmed a BA from 72 to 70 doing this.

John Siebold
 
thx all,

John, is there any sig problem with the 210 hp in the RV7? I was looking at superior's engine, similar hp....obviously vans "can't endorse that HP, but you're the builder, so you can decide" was their answer..

das
 
More horsepower = better. Too much horsepower = best. You can always pull back the black knob.

Now let's see where this thread drifts.

John Siebold
 
200 HP +

I had a 200RV on the 7 that I sold and it was great. Smooth and reliable. The new 7 will have a new IO390 with Barrett Precision work done. It is close to 220 HP.

I consulted with Whirlwind and they said the 74 is most efficient with 200+ HP engines. Below that the 200RV is more effective. The 74 has more diameter and a thinner blade.

So, 200 or less go with the 200RV, 200+ consider the 74.
 
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