RL Cherokee pilots - your thoughts?

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mryan75
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RL Cherokee pilots - your thoughts?

Post by mryan75 »

For the real-life Cherokee pilots out there:

I think this rendition of the Cherokee is pretty freaking fantastic. I only have a few little nits to pick, the main one being the tendency to balloon when flaring. The Cherokee will do that at 90, but certainly not at 70. I kinda feel like it's hard to get a full-stall landing in this just because of that tendency to balloon, even at really low airspeeds. What do you guys think? I approach at 90, 80 over the numbers, chop the power once I have the field made, and it still feels like any amount of backpressure once you get near terra firma and it will balloon.

The only other thing that has struck me thus far is that even a 3-4 gallon fuel imbalance will make the aircraft bank, which I don't find to be the case in real life (not that you could tell a 3-4 gallon fuel imbalance in a real Cherokee, at least not by looking at the stock fuel gauges).

For the folks at A2A, you've done a wonderful job with this aircraft. Visually very accurate, in the cockpit and VC. I use this for practice approaches for my instrument rating, and it's fantastic!

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DHenriques_
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Re: RL Cherokee pilots - your thoughts?

Post by DHenriques_ »

mryan75 wrote:For the real-life Cherokee pilots out there:

I think this rendition of the Cherokee is pretty freaking fantastic. I only have a few little nits to pick, the main one being the tendency to balloon when flaring. The Cherokee will do that at 90, but certainly not at 70. I kinda feel like it's hard to get a full-stall landing in this just because of that tendency to balloon, even at really low airspeeds. What do you guys think? I approach at 90, 80 over the numbers, chop the power once I have the field made, and it still feels like any amount of backpressure once you get near terra firma and it will balloon.

The only other thing that has struck me thus far is that even a 3-4 gallon fuel imbalance will make the aircraft bank, which I don't find to be the case in real life (not that you could tell a 3-4 gallon fuel imbalance in a real Cherokee, at least not by looking at the stock fuel gauges).

For the folks at A2A, you've done a wonderful job with this aircraft. Visually very accurate, in the cockpit and VC. I use this for practice approaches for my instrument rating, and it's fantastic!
You can balloon a 180 at 70. The thing about "ballooning" is that most pilots associate it with excess airspeed. That most certainly is a factor but not the primary factor. The prime reason for ballooning is over controlling in pitch (the more airspeed the more sensitive the pitch).
The correct way to look at ballooning is that no matter WHAT airspeed you have going into the flare you have to compensate in pitch for THAT airspeed during the flare. What ACTUALLY will be the effect of excess airspeed is that the flare will be extended to your stall point so excess runway for sure. So at 90 you will be landing longer than at 70. Of course you can force it down onto the runway but that practically guarantees you a bounce into a balloon. You HAVE to get rid of the airspeed. THAT is why the over the numbers speed is so important. 80 to 85 over the fence is fine for the 180 Cherokee.
I haven't noticed any fuel imbalance issues with my Cherokee installation. I use a Warthog and I would be automatically compensating laterally without thinking anyway just as in the actual plane.
Dudley Henriques

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DC3
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Re: RL Cherokee pilots - your thoughts?

Post by DC3 »

I flew the Warrior and the Archer IRL, these have a different wing and more stabilator control I am told, but the A2A Cherokee is very uncanny in how close it mimics those two aircraft from the speeds to the handling. I can tell you IRL with the low wing the Warrior and the Archer will float and they have to be flown along the runway until the speed is gone and they won't fly anymore when the float happens. If at any point the nose is pulled up too hard the plane will 'balloon' and then land hard on the mains. On hot days and with ground effect a lot of runway can go by before the mains touch down. However if the speed over the numbers is close a 2500 to 3000 ft runway will give plenty of landing room even with the float. On good days the plane can get down and make the first turn off but all the speeds have to be right on the money and the plane needs to be ready to stall at the point the mains touchdown with the nose up. The Warrior, Archer, and Cherokee are all trainers so they get a lot of abuse on landings, but when you can get one to come in and have the stall and the mains arrive at the same physical location at the same point in time it feels good. There are many more landings where you are watching the far end of the runway getting closer and closer, sitting in the pilots seat holding the nose up pulling back on the yoke waiting for the speed to bleed off so the mains can settle on the runway, hopefully while there is runway left :)

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Nick - A2A
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Re: RL Cherokee pilots - your thoughts?

Post by Nick - A2A »

Hi Mike,

Glad to hear you're enjoying the Cherokee. :)

Just to add to Dudley's comments on over controlling, it's worth bearing in mind that our flight sim controls are typically much inferior to their real world counterparts in terms of 'feel' and throw. Although I'm not one, I believe that this can sometimes be an issue for RL pilots transitioning to a flight sim, and could be a potential culprit for any tendency to over control during the flare.

One suggestion is to make sure that the sensitivity and null zone of the elevator axis are set as recommended in this thread instead of left at the FSX/P3D default settings.

Thanks,
Nick

mryan75
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Re: RL Cherokee pilots - your thoughts?

Post by mryan75 »

Nick - A2A wrote:Hi Mike,

Glad to hear you're enjoying the Cherokee. :)

Just to add to Dudley's comments on over controlling, it's worth bearing in mind that our flight sim controls are typically much inferior to their real world counterparts in terms of 'feel' and throw. Although I'm not one, I believe that this can sometimes be an issue for RL pilots transitioning to a flight sim, and could be a potential culprit for any tendency to over control during the flare.

One suggestion is to make sure that the sensitivity and null zone of the elevator axis are set as recommended in this thread instead of left at the FSX/P3D default settings.

Thanks,
Nick
Once again, a great tip! Nick, I really have to give the A2A an A+++ for product support. Thanks a lot :)

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Nick - A2A
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Re: RL Cherokee pilots - your thoughts?

Post by Nick - A2A »

You're welcome Mike and thank you for the kind words. :)

Nick

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Re: RL Cherokee pilots - your thoughts?

Post by n421nj »

I find the elevator authority with no baggage to be a little squirrelly. With no baggage can’t get the nose up to flare and result in flat landings. With 100lbs of baggage it works like the real plane with maybe 10 lbs of baggage. Caveat is I fly a Cherokee 140 not 180. Either way not a big deal I just leave 100 lbs in baggage and good to go.
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zaruthoj
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Re: RL Cherokee pilots - your thoughts?

Post by zaruthoj »

I fly a '73 Cherokee 180 IRL, which is nearly identical to this model except for a longer fuselage and stabilator. I find little to no difference in performance during landing other than the lack of control feel.

I completely agree that the A2A Cherokee is too sensitive to right/left imbalance. I start to notice in the real thing at about 10 gallons imbalance.

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Re: RL Cherokee pilots - your thoughts?

Post by Hook »

zaruthoj, are you interested in trying to fine tune this?

Look in the aircraft.cfg file in the Cherokee folder. Most of the way down in the file you'll find the [fuel] section. This is where the fuel tanks are defined.

Code: Select all

LeftMain  = 0.45, -2, -0.4, 25.0, 0.0       //Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
RightMain = 0.45, 2, -0.4, 25.0, 0.0       //Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
If you change the 2 and -2 in those two lines to something smaller, it will move the effect of the weight of the fuel closer inboard and thus have less effect on left/right imbalance.

I suggest 0.3 then fine tune it to get the effect closest to your actual aircraft. The lines will then be

Code: Select all

LeftMain  = 0.45, -0.3, -0.4, 25.0, 0.0
RightMain = 0.45, 0,3, -0.4, 25.0, 0.0
A2A has done a similar adjustment to keep the pilot and copilot from having too much effect on lateral balance. Basically, treat these as numbers without units.

Please play with this a bit and let us know what you think the appropriate value should be. Either do tests in a no-wind condition or flying with wind from various directions, as wind can produce some banking and will interfere with your tests. At least in FSX. :)

Hook

mryan75
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Re: RL Cherokee pilots - your thoughts?

Post by mryan75 »

Hook wrote:zaruthoj, are you interested in trying to fine tune this?

Look in the aircraft.cfg file in the Cherokee folder. Most of the way down in the file you'll find the [fuel] section. This is where the fuel tanks are defined.

Code: Select all

LeftMain  = 0.45, -2, -0.4, 25.0, 0.0       //Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
RightMain = 0.45, 2, -0.4, 25.0, 0.0       //Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
If you change the 2 and -2 in those two lines to something smaller, it will move the effect of the weight of the fuel closer inboard and thus have less effect on left/right imbalance.

I suggest 0.3 then fine tune it to get the effect closest to your actual aircraft. The lines will then be

Code: Select all

LeftMain  = 0.45, -0.3, -0.4, 25.0, 0.0
RightMain = 0.45, 0,3, -0.4, 25.0, 0.0
A2A has done a similar adjustment to keep the pilot and copilot from having too much effect on lateral balance. Basically, treat these as numbers without units.

Please play with this a bit and let us know what you think the appropriate value should be. Either do tests in a no-wind condition or flying with wind from various directions, as wind can produce some banking and will interfere with your tests. At least in FSX. :)

Hook
WHat a fantastic idea. I noticed today that the fuel imbalance doesn't necessarily cause the plane to lean to the side with the greater fuel, but rather to make it kind of yo yo back and forth a bit. I'll toy with this a little and see what it does.

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Re: RL Cherokee pilots - your thoughts?

Post by Hook »

Thanks mryan75.

A2A has already moved the fuel points far inboard of where they would likely be on the real aircraft. The file shows the fuel at plus and minus two feet from center line. There is something odd about the way FSX/P3D calculates lateral imbalances that exaggerate it considerably. The math might be right but the effects aren't. The factor seems to be at least 20 and possibly as high as 40.

I'd really like to get a couple of real world Cherokee pilots outside of A2A experimenting with these numbers. I've found that there is a noticeable imbalance if the fuel is more than about 2 gallons different between tanks. According to zaruthoz this should be closer to 10 gallons, which makes sense in that if you use fuel from one side for an hour, then the other side for two hours, this will keep the numbers within 10 gallons. After a lot of tests and calculations I decided on 0.28 but I need to do a long flight emptying two full tanks to confirm it.

I found that the Cherokee before the update was laterally unstable anyway with a constant yo-yo. The update seems to have fixed that, but I haven't really flown enough to be certain. I was about to uninstall the Cherokee when I realized that upping the roll_stability from 1.0 to 2.0 might fix the problem, and it did, flying in the same conditions. I forgot to do this change after the update then realized it was not necessary. Since the update I really enjoy flying the plane. I just don't fly modern aircraft all that often.

A2A aircraft require the fewest tweaks of any aircraft I've flown. Normally it is just fine tuning the position of the Virtual Cockpit eyepoint. The biggest changes were adding a 2D pocketwatch to the Cub and adjusting the Stratocruiser bounding box. A2A is unique in my experience in that their cockpits are finished. If an A2A gauge is supposed to be reading a certain number, it does, even if the internal number is different. The worst offender in this was a clock that had the hour and minute hands swapped in a 65 Jaguar in another sim.

Hook

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Re: RL Cherokee pilots - your thoughts?

Post by Hook »

After responding to this thread I had to fly the Cherokee after a lapse of two months. Las Vegas to San Diego. It wasn't as long a flight as I wanted for a test, but was long enough.

I was getting about 7 gallons per hour, balanced load, full tanks, 2330 RPM. I started the flight feeding from the right tank. I didn't notice any imbalance until the gauge read 14 gallons, a difference of 11 gallons from the left tank. By the time I switched tanks (I later found it was at 13.75 gallons) there was considerable imbalance. After switching the imbalance went away fairly quickly.

I was using plus and minus 0.28 for the fuel tank lateral offset. When I had tested with 0.30 the imbalance was somewhere over 11 gallons. At 0.25 it was around 8 to 9 gallons but I may have been using fuel from the left tank for that one.

I consider the imbalance noticeable when you have to concentrate on keeping the plane on a particular heading and it always drifts to the same side. I am not talking about subtle forces here, but fairly pronounced. It is less apparent in turbulent air. If I don't have to think about it, then I consider that to be a state of no imbalance. It is interesting to note that the transition feels a bit abrupt, even if the atmosphere doesn't change. It happens over the course of a minute or two.

Hook

Edit to add: Rudder trim was set at 0.0 and all controls were properly calibrated. The next flight will test the imbalance in the other direction.

Hook
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Re: RL Cherokee pilots - your thoughts?

Post by Hook »

On the next flight the right tank had 13.7 gallons. When the left tank got down to about 6.3 I started seeing symptoms of the right side being too heavy, barely noticeable. By the time the left tank got down to 5.6 it was annoying. That is an 8.1 gallon difference, and it took longer for the effect to go away when I switched tanks again.

These cannot be compared directly because there were many differences: lighter aircraft (creating a different angle of attack), slightly different power settings, slightly different weather conditions, engine torque, psychological factors, whatever.

Next flight I'll use full tanks and start with the left.

This is likely not something that can be calculated but has to be adjusted until it feels right for the individual. My controls aren't the same as yours, for example, and my expectations may be different as well as what I find acceptable. I'd rather tweak an aircraft than uninstall it, and the Cherokee is just too good to discard.

Hook

zaruthoj
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Re: RL Cherokee pilots - your thoughts?

Post by zaruthoj »

Hi, sorry I didn't notice the question.

I played with this a bit on a recent flight. My experience mirrors Hook's pretty closely. I started to notice the inbalance at 6 gallons, and it was annoying at 8-9 gallons.

This was IMC though, so I would have been more aware of the corrections required. I might not have noticed until 8-10 gallons difference if I had been VFR.

I'll play with those numbers and see what feels right.

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scottb613
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Re: RL Cherokee pilots - your thoughts?

Post by scottb613 »

zaruthoj wrote:Hi, sorry I didn't notice the question.

I played with this a bit on a recent flight. My experience mirrors Hook's pretty closely. I started to notice the inbalance at 6 gallons, and it was annoying at 8-9 gallons.

This was IMC though, so I would have been more aware of the corrections required. I might not have noticed until 8-10 gallons difference if I had been VFR.

I'll play with those numbers and see what feels right.
Hi Folks,

I fly a similar low wing plane in the RW - 30 gallons in each wing - honestly - I don’t think I’ve ever been able to detect a fuel imbalance by the way she flies... I’m sure I’ve had some pretty substantial imbalances at various points through the years...

On long distance flights - I usually burn the first tank for an hour - burn the second tank until near empty - switch back to the first for whatever I need - with an hour left in reserve - and landing... I’d rather have my available fuel in a single tank - rather than a little bit in both tanks - that the traditional 30 minute flips get you...

I haven’t done any testing of this on the A2A Cherokee though - in regards to this...

I recall FS9 was so sensitive to fuel imbalances that I modded most panels that had only left and right positions - to include a gauge that had a “both” position... In as little as 10 minutes you could get a noticeable fuel imbalance - pretty unrealistic...

Regards,
Scott



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