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-   -   whirlwind 74RV in taildragger? (https://vansairforce.net/community/showthread.php?t=131063)

DAS 10-28-2015 01:07 PM

whirlwind 74RV in taildragger?
 
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

flyinga 10-28-2015 01:19 PM

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.

miyu1975 10-28-2015 01:20 PM

I fly a 74 inch hartzell on my TW rv7, no problems with ground clearance.

DAS 10-28-2015 03:22 PM

thanks, I'm a RV7 tailwheel

das

Larco 10-28-2015 03:26 PM

74 inch Hartzell RV 7 works for me over 1000 hrs

Larry

gblanck 10-28-2015 05:43 PM

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.

greghughespdx 10-28-2015 05:57 PM

For people flying the 74RV, curious what engine and HP you're running with?

ronschreck 10-28-2015 07:08 PM

Not to worry...
 
Mine is a 78-inch Hartzell composite constant speed. Still plenty of clearance.


OGee 10-29-2015 11:24 PM

Whirlwind 72" vs the 74"rv
 
Quote:

Originally Posted by DAS (Post 1025208)
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

Any performance comparisons between these two props - actual or hearsay?

gblanck 10-30-2015 01:00 AM

Quote:

Originally Posted by OGee (Post 1025696)
Any performance comparisons between these two props - actual or hearsay?

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.

RV7ator 10-30-2015 11:11 AM

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

DAS 10-30-2015 03:11 PM

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

RV7ator 10-31-2015 09:22 AM

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

RV7Guy 10-31-2015 09:41 AM

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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