Set a new personal speed record in my RV9A

[Desert Rat]

I'm in build mode and have never flown any RV as of yet. BUT I know a thing or two about airplanes in general and about flight instruction in particular. I've been an A&P and CFI for just about 30 years now and can tell you with 100% confidence that Flight instructors don't know everything, no matter how knowledgeable they are.

In this case, your instructor is mistaken. It's understandable that he would think that, because the Vne in most certified piston singles is listed as IAS. When I was deciding whether or not to build an RV I also assumed RV's were like that. They are not.

VNE on the RV series is in TAS. Van has made this clear in documentation that was linked and recommended to you in the very first reply to your original post on this thread.

If you are diving that airplane under power at 234 MPH TRUE AIRSPEED you are well above VNE as explained by Vans.

I'm not trying to scare you or argue or whatnot, but you've got 5 pages of people on this forum telling you that you genuinely owe it to yourself and your loved ones to understand this. Please at least consider the possibility that the majority opinion is probably the correct one.

If you like, I'd be happy to talk with you or your flight instructor off line and go through the details, but if you just read what vans published, it should become clear.

[RV8JD]

Originally Posted by Earl Findlay

No documents that I have on the RV9A show the Vne as an TAS. I spoke to my instructor about this, and he confirms Vne is an IAS. Please folks, off the high horse.

From the RV9A manual, chapter 15 “Flutter testing of factory prototypes has resulted in establishing a NEVER EXCEED SPEED (Vne) of 210 statute mph for the RV-3, 4, and RV-6/6A, 230 statute mph for the RV-7/7A/8/8A, and 210 statute mph for the RV-9A.”

Do you see true airspeed listed there? No? Neither do I.

To cover my rear end, I made a logbook entry stating that the aircraft was put into Phase I, Vne tested to 210 MPH indicated, no adverse affects seen, and Vne established at 210 MPH indicated. Hopefully this satisfies those members who were worried about exceeding some sort of limit.

And therein lies part of the problem, Van's lack of disseminating updated information via a Service Bulletin or Service Letter when they changed from Vne being in terms of IAS to TAS for the older models, per my Post #30. I've brought this issue up several times on VAF, and corresponded directly with Van's about it also. I hope that this thread finally gets Van's attention and they finally get official information out before an accident occurs.

But Earl, the responses you received in your thread "I am afraid of my 360 powered RV 9A" clearly communicated the correct info to you. Why you chose to ignore it, or at least question it, is beyond me.

[rvbuilder2002]

Originally Posted by RV8JD

And therein lies part of the problem, Van's lack of disseminating updated information via a Service Bulletin or Service Letter when they changed from Vne being in terms of IAS to TAS for the older models, per my Post #30. I've brought this issue up several times on VAF, and corresponded directly with Van's about it also. I hope that this thread finally gets Van's attention and they finally get official information out before an accident occurs.

But Earl, the responses you received in your thread "I am afraid of my 360 powered RV 9A" clearly communicated the correct info to you. Why you chose to ignore it, or at least question it, is beyond me.

This is being worked on (sometimes the gears turn slowly)
In reality though, would it make a bit of difference in this case?
The OP has already been referred to two documents publish by Vans that go into pretty specific details regarding the subject. Along with numerous forum discussions that make it clear ( though I admit there are always posts that muddy the water a little bit).

[hohocc]

Perhaps the OP should enter the details of post number 1 in his aircraft logbook for any future buyer to see.
Other posts by the same person detail the construction of an RV14, so could he please publish his current 9a aircraft N number for the various prebuy inspection providers to make a note of for when that aircraft comes on the market.

[tjo]

A few things.

First, that table of speeds is a big reason why the 9 is the greatest plane that vans offers, 49mph stall (at gross) with 180-200 mph cruise is fantastic! (Yes, slower if it is rough, but that sucks in any case)

Second, flutter sets Vne. Flutter is difficult to predict as it depends on structural natural frequency and aerodynamic driving forces. Structural natural frequency, while straight forward to analytically predict, is difficult to actually predict due to differences is airframe construction, not design. Aerodynamic driving forces are somewhere between difficult and impossible to predict.

Third, as a result of second, significant margins are put in place to make sure that flutter never happens... ever. That means significant margin.

Forth, significant margin can turn into zero margin at unpredictable conditions. One successful, or 100 successful times at exceeeding the limits does not mean the next will end well.

Finally, Vans has stated that Vne is TAS, repeatedly and forcefully. I am building a 9, I plan to put in a 360, and I plan to stay below the TAS limit of 210 at all times, and I will have one of the best performing airplanes of all time.

Tim

[Toobuilder]

Originally Posted by Earl Findlay

...To top the day off, I thought I'd have some fun and set off to make a personal true airspeed record as well as a max altitude record today. I left the engine RPM at 2700 on the descent, and took it up to the airspeed redline and excepted whatever vertical speed the airspeed would give at the altitudes on the descent. Out of 16400 feet I peaked at 234 true, 239 groundspeed. What a hoot!!!!

I think you will find me cruising around at the higher altitudes a lot more in the near future.

Earl - I do flight test for a living. I've been a FTE, a TD, and an Air Vehicle Manger. I'd say you need to do a "safety stand down" and figure out a few things before you fly again. First off, you don't seem to have a grasp of the difference between TAS and IAS and that will kill you. Second, you have spent time WAY out of the envelope and that needs to be addressed before the airplane can be flown again. I get nervous at 235 KTAS in my Rocket and limit the RV-8 to 200 - both significantly stronger airplanes than yours. You need to perform an "overspeed inspection" before you take it up again.

You've read some good advice in this thread. I'd suggest you step back, re evaluate, and move forward with a new plan.

[lr172]

Originally Posted by rvbuilder2002

This is being worked on (sometimes the gears turn slowly)
In reality though, would it make a bit of difference in this case?
The OP has already been referred to two documents publish by Vans that go into pretty specific details regarding the subject. Along with numerous forum discussions that make it clear ( though I admit there are always posts that muddy the water a little bit).

don't think we have any chance of convincing the OP; that is not Van's fault, as he is choosing to ignore published data provided to him. However, he is relying on his CFI's opinion. Folks like that, outside of the VAF community, need to be informed. They help shape the beliefs of pilots.

While some will ignore cuations and limits, I suspect most simply don't know that Van's changed from IAS to TAS. Outside of VAF, I don't believe it is well publicized.

Larry

[rvbuilder2002]

Originally Posted by tjo

I plan to stay below the TAS limit of 210 at all times, and I will have one of the best performing airplanes of all time.

I am glad to hear that but frustrated to see your post that once again implies to others that read here, that as long as Vne (TAS) is obeyed that all will be fine.

Vno is equally important because it is in esance a high performace airplane that (unlike most of teh other RV's) was not designed to aerobatic load limits, but as is so often mentioned, the great performance of the RV-9 makes Vno a limit that is also very easy to exceed.

[tjo]

Originally Posted by rvbuilder2002

Vno is equally important because it is in esance a high performace airplane that (unlike most of teh other RV's) was not designed to aerobatic load limits, but as is so often mentioned, the great performance of the RV-9 makes Vno a limit that is also very easy to exceed.

Which is why I referenced rough air in the first point. I plan to pay attention there as well, but rough air is not fun in any airplane; that's my point, not to cavalierly go past Vno.

Tim

[Earl Findlay]

Originally Posted by SPX

Earl -

I happen to be in Coeur d'Alene this weekend for work (I am here now). How about we get together and have a one on one discussion? I own an RV-9A with an IO-360, and have spent quite a lot of time researching the limitations of the airframe with the engine, and maybe I can provide you some honest, real world information about this setup, and the things that you may want to watch out for.

Please get in touch if you're interested in spending some time together.

Thanks but no thanks. My CFI has given me a good checkout, and he knows his stuff.

This ?NO 360!!? Policy stems from one thing and only one thing. Vans did not want big engines in the RV9A for fear of it competing with the more expensive kits. When the secret came out that a bigger engine makes this airplane a 200+ knot airplane they came up with this true airspeed policy which, ask any aerospace engineer, is completely bogus. The airplane knows IAS only.

Think about it ? if the airplane suddenly now knows true airspeed, why is the limit not tied to true airspeed OR groundspeed, whichever it hits first?

I am all ears; please do tell, why not base the speed limit on groundspeed if it was simply due to flutter?