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-   -   I am afraid of my 360 powered RV 9A (https://vansairforce.net/community/showthread.php?t=182010)

Earl Findlay 05-02-2020 01:44 PM

I am afraid of my 360 powered RV 9A
 
I have spent extensive time online reading about overpowered 9As. My 9A is a 360 powered one, and I've realized that I am in over my head.

I am wondering, to be cautious should I make redline of my 9A Vc, which appears to be about 170 MPH. https://www.vansaircraft.com/wp-cont...2/hp_limts.pdf

Is it true that I am safe as long as I keep the true airspeed below 170 MPH?

Thank You.

Earl

lr172 05-02-2020 01:52 PM

being safe comes in many forms and levels. Not sure what you are afraid of or concerned with. VNE/futter, aircraft control, exceeding G limits from wind gusts, etc.

I routinely fly to the edge of Vno and often beyond that in non-turbulent conditions.

Larry

CanyonDweller 05-02-2020 02:20 PM

http://www.vansairforce.com/communit...d.php?t=181789
Read what Airguy did last weekend in his 9A, and be sure to read his sig line at the bottom of his post.

RV8JD 05-02-2020 02:25 PM

Since you referenced the Van's article on HP limits, Vne, and TAS, I assume you are concerned about Vne as a function of altitude.

Vne (Redline) for the RV-9/9A is 210 MPH TAS/182.5 KTAS (although you wouldn't know it from official Van's literature). The table on the left in the chart below shows Vne in terms of IAS at different altitudes for a Vne of 210 MPH TAS/182.5 KTAS.



Vno (Maximum Structural Cruising Speed) is 180 MPH IAS for the RV-9/9A. Note that at 10,000 ft, Vno is about equal to Vne. Above 10,000 ft, Vne is lower than Vno and governs.

Hope that helps,

bjdecker 05-02-2020 02:32 PM

Don't be afraid...
 
...do more flying...

Per the manual, the Vne for the RV-9 is 210mph. Vno is 180. Va is 118mph

Consider the extra 20hp (assuming that you have an O-360 or IO-360-B variant of 180H.P.) a gift that yields shorter take off rolls, faster rate of climb, higher cruise, more performance margin...

lr172 05-02-2020 02:48 PM

Quote:

Originally Posted by Earl Findlay (Post 1426996)

Is it true that I am safe as long as I keep the true airspeed below 170 MPH?

Thank You.

Earl

No. Va is well below that. You need to better understand the conditions you encounter and how they relate to airframe safety. A full elevator pull at 170 will likely create serious damage.

Larry

rockwoodrv9 05-02-2020 07:33 PM

Earl,
I have a car that will do about 170mph. I dont drive it that fast. When I am on rough roads, I drive it much slower.
Considering you are north of me (KEUL), the extra hp will be nice in the mountains. I really wanted a 360 but got too good of a deal on a 320. Let me know if you want to trade!

terrye 05-02-2020 08:43 PM

I am afraid of my 360 powered RV 9A
 
The RV-9A standard engine of 160 hp is the same engine as used in Cessna 172s and Piper Cherokees, both 4 place planes. Based on that, the RV-9A is "overpowered", meaning it has a higher power to weight ratio, and this is responsible for its remarkable performance. A 180 hp (I)O-360 is only 12.5% more powerful, so you might even find the standard 160 hp engine "over your head" too. The solution is likely more training with a qualified instructor. And remember, the throttle works in both directions.

airguy 05-03-2020 07:23 AM

Yesterday afternoon I departed KSJT at 103F on the ground, don't even want to guess what the runway surface temperature was. Density altitude was 5800. Two butts in the seats and 28 gallons plus about 40 pounds in the baggage compartment. I came off the runway on an intersection departure and pitched for about 95 knots in the climb, about a minute and a half later Tower calls me and asks "What engine do you have in that thing?"

I was climbing at 1600/min in that heat with that load - and I wasn't really pushing it.

THAT'S why we (some of us, anyway) put 360's on the 9. It's not for flat-out speed, because it doesn't buy you any more Vne or Vno or Va - those are structural limits and you ignore them at your own peril. It's for the ability to get out of Indian Country and get up high quickly and let that wing do it's thing in mid teens where it wants to be.

Think of it this way - if you are worried about the extra horsepower, don't use it. Simply limit your maximum manifold pressure by 2" less than whatever airport you are taking off from, and you'll be equivalent to the 320. Just because you HAVE the extra horsepower doesn't mean you must use it. Just like a new car driver with a hopped-up mustang, ease into it gradually and feel it out, rather than going drifting around the street corners. The extra power is really nice when you want it - but it's optional, and you have the control literally in your hand.

FORANE 05-03-2020 07:29 AM

Quote:

Originally Posted by airguy (Post 1427139)
Just because you HAVE the extra horsepower doesn't mean you must use it.

I'm not sure this is accurate information. :)


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