Random Flying notes from this weekend

Here's a brain-dump of some notes from this weekend's flying in my new 9A.

I now have 5.3 hours on 9612S and about 20 landings or so. The garmin 196 automatically (no buttons required) records all flights under the 'flights' tab, so no cheating by counting taxi time. Take off and land an hour later and you'll see a flight recorded in the tab. It shows date, flight time, distance, airports visited and lots of other cool info.

At 4 hours, I passed that magic milestone where I feel very comfortable in the plane now. Nothing is going to fall off and the prop is going to keep spinning. After 5.3 hours, I think I will now stop taking the cowling off after every flight for an inspection and cutting and reinstalling the safety wire to make sure the gascolator is clean. Maybe after every 2 or 3 hours for a while...

I also recorded my longest flight of 1.4 hours and 200 plus miles. I had been doing .7 hours max and coming down for an inspection. I can see I'm going to get bored with my Phase 1 flight area even though it's big.

She loves to fly at 2100 RPMS at 109 knots IAS (120 True) IAS at 5.3 gph. That's 26 miles to the gallon -- as good as my wife's Camry and better by far than my truck.

I finally fully stalled her in various configurations. 42 knots IAS with full flaps, 44 with about 1/2 flaps, and 48 no flaps. This should come down when I get the fairings installed, but I am very happy with this. I'm having way too much fun to think about fairings right now.

The fastest I went this weekend is 145 knots true (166 mph), and I was there for no more than a few seconds. I think she'll top out at more than this even without the fairings. I didn't investigate the high end this weekend like I though I would...maybe tonight?

In my opinion, holding 70 knots on final way too fast. 60 is all you need on calm days, 65 max. You could go slower for short field. That's my own opinion so please consult more knowledgeable sources before flying like I do. 60 is still nearly 1.4 X stall speed.

With full power applied for take off, the rudder is STIFF, and I mean STIFF. For a few seconds I thought it was jammed. (I later laughed at myself, so go ahead and laugh too). You actually need to hold some right rudder all the way up to altitude when climbing with full power (which I only do on takeoff). I guess it's the p-factor. After leveling out she flies ball centered with feet off the pedals. Even most turns don't need rudder input.

I got 2 hours in an RV-7A last week with a CFI for my insurance requirement. The thing that strikes me the most is not the differences but the similarities. They feel exactly the same. The RV-9A's control feel stiffen up more at higher speeds (or for the rudder, higher power), but that's the only 'feel' difference that I could discern. But, the power off sink rate on the 7A with a constant speed prop was 1750 ft/min. My 9A is somewhere less than 500 feet per min...a big difference. The issue with this that my CFI pointed out is that when you give it the gas on a go around, it takes substantial time to actually stop the decent. He said a lot of people get in trouble because they wait till they're too close to the ground for a go around and then try to stop the decent with by pulling back, increasing the sink rate and hitting very hard. This will be much less of an issue in the 9A, but still, be on the look out for it. Decide to go around early if you're going to do it.

That's about it for now. I'll be going out of town this week so tonight is my only chance to fly until Saturday. I'm going to miss it.

Im really curious about any real comparisons between the 7a and 9a. The note about the power off drop rates was important- a huge difference.

Comparing the performance summaries supplied by Vans, I noticed that both aircraft were very close with a 160HP motor across the board. Assuming that the power were to be increased (w/weight held constant) on a 9a in step with a 7a, I wonder if the performance specs would continue to be as close as with the 160HP motor?

My other big question is just what maneuvers can the 9A safely do- my guess is stuff like a soft Cuban8, Immelman, aeleron rolls, possibly a hammerhead but no dive related stuff, like a split-s or loops. I do wonder how steep of turn is realistic, ie, is a 90 degree bank out of the question?

cobra said:

My other big question is just what maneuvers can the 9A safely do- my guess is stuff like a soft Cuban8, Immelman, aeleron rolls, possibly a hammerhead but no dive related stuff, like a split-s or loops. I do wonder how steep of turn is realistic, ie, is a 90 degree bank out of the question?

Click to expand...

I don't want to hijack this great thread, so I will make it quick. Van's did not make the 9 for the purpose of aerobatics, and if that is what you are looking for, I would seriously look at another model. IMHO, what is safe in the 9 is to follow what the Kit supplier recommends and leave the aerobatics to the other RV's.

I understand and appreciate your comment. I believe the maneuvers I mentioned involve climbs and normal turns; since they do not require high G-forces, they should be usable in our bag of tricks. Steep dives are obviously out. You might note I used the adjective "safe"...

Im just trying to get a feeling of what the 9s are capable of; Im still on the fence between the 7 and 9 and there simply has not been a lot of stick-comparisons (nor performance specs) posted so far between them that Ive seen.

cobra said:

Im just trying to get a feeling of what the 9s are capable of; Im still on the fence between the 7 and 9 and there simply has not been a lot of stick-comparisons (nor performance specs) posted so far between them that Ive seen.

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I was where you were about 2 years ago... asked the same 7 vs. 9 question on other forums. I think the short answer to your aerobatics question is you CAN do whatever aerobatics you want so long as they do not exceed the G-force Van's created the structure to support. Many aerobatic maneuvers can be done without pulling significant G's. The problem is that RV's are so slippery that unless you are very proficient aerobatically, what starts out as safe can quickly become unsafe. No 1-g rolls for me, even if the 9 CAN handle it.

The other issue... I picked the 9 precisely for the low sink rate compared to the 7 that you mentioned. The most commonly reported numbers I've heard from other "fliers" is that the power-off sink rate of the -9 is about 600-650fpm vs. about 1500 for the 6/7/8. To me that's a BIG deal! That's twice the amount of time to decide what you are going to do if the engine quits (+ you'll more likely glide farther in the -9). OneTwoSierra posted his observations above which seem to argue for an even greater difference. Because I don't care about aerobatics (though I too would love to be able to do the occasional roll), I chose the -9, for the sink rate and lower stalling speed alone. Remember that lower stall speed, though seemingly a small difference--7 mph I think--equates to an exponentially greater survivability if you hit something. I may be too conservative, I don't know, but unless aerobatics are necessary (and you're willing to wear a parachute every time you fly just in case you get the urge to do a roll--which I'm not), to me the 7 vs. 9 choice is a no brainer.

That's just my thinking, but I hope it helps you make YOUR decision.

Good luck.

Steve

With sink rates, be sure you're comparing apples to apples.
The difference in sink rates stated by the first poster was for a '7 with constant speed prop, and he doesn't actually state what prop he has on his '9 so it may very well be a fixed pitch prop.

From what I've read, it's the "advantage" of a high sink rate available with a CS prop that is one of the reasons that people choose CS props.

It would be nice, in order to make a "real" comparison, if numbers were to be posted by people with a '7 and the same prop as the original poster has on his '9.
I understand the Roncz airfoil of the '9 is a highlift airfoil, but I'm a bit skeptical that it would result in a glide that much different than a '7 if it had the same prop.

RV9(a) comparison to RV6/7(a)

cobra said:

I understand and appreciate your comment. I believe the maneuvers I mentioned involve climbs and normal turns; since they do not require high G-forces, they should be usable in our bag of tricks. Steep dives are obviously out. You might note I used the adjective "safe"...

Im just trying to get a feeling of what the 9s are capable of; Im still on the fence between the 7 and 9 and there simply has not been a lot of stick-comparisons (nor performance specs) posted so far between them that Ive seen.

Click to expand...

I agree with "Airwolf's" comments.

If you want to be "safe" and do those maneuvers, the get the same plane with the "stronger" wing (the 7).

Sure a really smooth pilot could probably do those maneuvers with no problem. But unless you have lots of stick time doing those in an RV (or similar) plane (and I know nothing about your skills) then there is the CHANCE that you MIGHT botch the manuever and now instead of 2 g's you might be at 6 g's or more and scattering parts around the country-side.

I did a few hammerheads (with and INSTRUCTOR ... in his plane) and it was amazing how fast the airspeed built up on the downside. I kept reminding myself to "don't go redline and DO NOT pull off the wings!!" I would not want ME to try that in the 9(a).

Now I have a friend who taught pilots to fly Cubs, Stearmans, T6's etc, etc for WWII. He has lots of hours in an RV6a and was silky smooth in it. He now has a 9a and I bet HE could safely do the manuevers. BUT, he has x,000 hours doing this in all sorts of planes.

As to the relative handling ...

The 6's I have flown feel the most responsive. The 7 felt just a little heavier on the stick (could have been plane variation).

The 9 is a different feel to me. Within SMALL ranges of stick motion, it feels like the 6/7. The stick forces get much heavier on wider deviations, giving at least a sense of, greater stability. That stick seems to want to stay in the center and keep the plane really stable. I much more readily take my hands off the stick in the 9 to fold charts, look down and write stuff etc, than in the 6(7?). It just feels oh so much more "stable" whereas its bretheren feel a lot more, shall we say, "responsive'.

The earlier references to the speeds are also something I agree with. I fly my friends 9a (for takeoff and landing) using the same "numbers" as the 6 but in MPH as oppposed to KTS. This makes the takeoff and landing speeds about 15% lower/slower for the 9a than the 6 and even then I feel a bit fast on final.

In **my** opinion,
the 9(a) "feels" more stable
the 9(a) is a better IFR platform (due to above)
the 9(a) is better for operating out of really short fields
the 9(a) is a really nice ride
Van's says aerobatics are not "OK" in the 9(a)

the 6/7(a) **IS** more "responsive" throughout the stick range
the 6/7(a) is a better formation platform (due to above)
the 6/7(a) works GREAT out of really short fields (once you understand descent rate mentioned before
the 6/7(a) is a really nice ride
Van's says (limited) aerobatics are "OK" in the 6/7(a).

.

In summary, I would say ... decide what you want to do with the plane (mission profile) and then pick the one Van's recommends for that and go have fun. And don't try to make an apple a pear.

Maybe yet another way to look at this is "what do you think is "safe" to do in a Cessna 152/172 (not the Aerobat or whatever)? If you can safely do in those, you **probably** can "safely" do it in a 9(a).

Disclaimer: I am NOT an Aeronautical engineer nor a CFI. Use at your own risk. Your mileage may vary. Etc., etc., etc.

Highflight said:

With sink rates, be sure you're comparing apples to apples.
The difference in sink rates stated by the first poster was for a '7 with constant speed prop, and he doesn't actually state what prop he has on his '9 so it may very well be a fixed pitch prop.

From what I've read, it's the "advantage" of a high sink rate available with a CS prop that is one of the reasons that people choose CS props.

It would be nice, in order to make a "real" comparison, if numbers were to be posted by people with a '7 and the same prop as the original poster has on his '9.
I understand the Roncz airfoil of the '9 is a highlift airfoil, but I'm a bit skeptical that it would result in a glide that much different than a '7 if it had the same prop.

Click to expand...

I easily see a 1000FPM sink rate on an RV6/O-320/Sterba Fixed Pitch Wood Prop unless I do something about it (on final). And I do think it IS important to do something about it before you get too close to the runway of course.

I think I see about 1/2 of than in an RV9a/O-320/Sensenich Fixed Pitch Metal Prop (**at a LOWER airspeed!!**).

The GLIDE (for the 9<a>) is **SIGNIFICANTLY** greater based on my perceptions. You **MUST** get the 9(a) slower than the 6(a) or you will float a few more thousand feet than where you would normally land with the 6.

This not a problem in either plane. You just have to know that they are *different* and fly accordingly. Both fly and land just fine. Just a little differently.

The CS prop "braking action" is more the benefit in the mind of some. I think the high sink rate is a by-product that can be used (or abused).

Just some more "opinions".

James

Highflight said:

With sink rates, be sure you're comparing apples to apples.
The difference in sink rates stated by the first poster was for a '7 with constant speed prop, and he doesn't actually state what prop he has on his '9 so it may very well be a fixed pitch prop.

From what I've read, it's the "advantage" of a high sink rate available with a CS prop that is one of the reasons that people choose CS props.

It would be nice, in order to make a "real" comparison, if numbers were to be posted by people with a '7 and the same prop as the original poster has on his '9.
I understand the Roncz airfoil of the '9 is a highlift airfoil, but I'm a bit skeptical that it would result in a glide that much different than a '7 if it had the same prop.

Click to expand...

You're right these aren't apples to apples comparisons. My prop is a fixed pitched Catto 3 bladed prop. Also, this wasn't a controlled test of any kind. We just pulled the power and and raised the nose to slow her down (to what speed I can't remember) for a demonstration, and so the sink wasn't optimized. However, you should understand that with the same props they would still be very significantly different because its the wing design is the primary design difference between the two planes.

I certainly didn't intend to start a 7 vs. 9 war, which could very easily happen if people misunderstand my original post. I've got all of ONE demonstration of that aspect of the 7, so what do I know? I didn't mean to disparage the 7. Its a great, great plane for its mission...with a higher sink rate of some unknown degree.

I hope you're not taking my comment defensively because it certainly wasn't meant to be a criticism of your observations.

I take some interest in this because I'm building a 7A that will have an IO-360 and also the Catto 3-blade fixed pitch prop. The better I have a feeling for what performance to expect, the better I can explain to Craig Catto what my priorities are for performance of his prop.

I really am just curious to hear about any and all comparisons of performance for like-equipped aircraft.