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X-Plane 11 C152 flight dynamic feedback

Printed From: Just Flight Forum
Category: Just Flight Products
Forum Name: C152
Forum Description: Discussion area for C152
URL: http://forum.justflight.com/forum_posts.asp?TID=32334
Printed Date: 14 Oct 2019 at 6:32pm


Topic: X-Plane 11 C152 flight dynamic feedback
Posted By: stephane130281
Subject: X-Plane 11 C152 flight dynamic feedback
Date Posted: 27 May 2018 at 6:46pm
Just bought the C152 for X-Plane. Amazing plane and love it! Visual model and sound are really great. I have a lot of hours on the real plane as it was also my trainer plane. I did notice few stuff that would be great if improved:
1. Side slip during direct crosswind: lack of rudder authority even when approaching a higher speed 70 kts and flaps 10.

2. No engine effect at low speed: center of thrust is below the center of gravity in this plane. So when adding power, the vertical speed should immediately increase and the other way around. A C152 should be landed using throttle to set the vertical speed and yoke to set the airspeed and not the other way around.

3. During traffic pattern, on downwind, in the real aircraft I can maintain 80 kts and 2000 RPM. In the sim I need 2300 RPM.

4. Same in crosswind: 500 to 600 ft/min of descent, we should be able to keep 65 kts with flaps 20 and 1700 RPM. I need 2200 RPM.

5. In final 30 flaps and 65 kts I need 2300 RPM which is way too high and almost full power. That s not realistic at all.

6. Steering is too sensitive on the ground

7. Would be great to have the possibility to reduce the sound of the engine only. It is too loud. We can reduce it but that s reduce the sound of the avionics up to the point that I can t hear the VOR ident morse anymore.

8. Would be nice to switch off the tips appearing on the screen when fooling for instance or vapor lock. That s really ennoying when it pops up on the screen.

9. Adding key binding possibility for the primer lever and fuel switch for home cockpit user like me. I don t use keyboard nor mouse anymore so any single function that could be key binded would be awesome!

10. Notice that you simulate a fuel pump on the C152. There is no fuel pump on a C152 unless it depends on model. On mine there is no fuel pump.

11. One can start the engine without priming when engine is cold. It needs at least 3 to 5 injections in real life to be able to fire the engine up.

12. Adding flaps does not pitch up the plane while in the real plane, setting flaps 10 at 80 kts really pitch up the plane and we have to push hard on the yoke to keep it level.

If you could take all these point of improvements listed above, that would be awesome!

Thanks again for this beautiful aircraft.
All the best!



Replies:
Posted By: Martyn
Date Posted: 29 May 2018 at 9:15am
Thanks for the comprehensive feedback. We'll pass this on to the development team so they can investigate.

Martyn


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Martyn
Just Flight Ltd


Posted By: sd_flyer
Date Posted: 29 May 2018 at 3:16pm
Also would you consider adding retrofired NGS430 and Glideslope to CDI for IFR capabilities? 


Posted By: sd_flyer
Date Posted: 29 May 2018 at 3:24pm
Originally posted by stephane130281 stephane130281 wrote:


2. No engine effect at low speed: center of thrust is below the center of gravity in this plane.

What is center of thrust? Do you mean thrust line? Center of pressure?


Posted By: NoJoe
Date Posted: 30 May 2018 at 8:25pm
Hi Stephane,

I'm Joseph, one of the developers of the C152 at Thranda.  Thank you very much for the feedback!!

We've incorporated several changes that will be in the next version: We've raised the CG slightly, decreased the flaps drag slightly, increased the rudder effectiveness, and decreased the steering sensitivity slightly.  These changes should address your numbers 1, 2, 5, and 6.

For your other items, I'll reply here by number:

3, 4, 5. I'm finding that I get exactly 80 knots at 2000 RPM in level flight.  Are your flaps retracted?  When I accidentally left the flaps at 10 degrees, I indeed had to use 2300 RPM to maintain 80 knots.  Also, aircraft weight will affect this somewhat (but not much).

Similarly, I find that flaps 20 and 1700 RPM and 65 knots gives me a 500 fpm descent.  And once I go to flaps 30 and maintain 65 knots, I get around 600-700 feet per minute.  We slightly decreased the flaps drag, so this should help.

A note: in the simulator we tend to want to fly a shallower approach than we would in the real world, so that might be a contributing factor here.

7. The engine sound volume can be lowered via X-Plane's built-in sound settings window.  Open X-Plane's Settings window, select the "Sound" tab, then adjust the "Aircraft Exterior" and "Aircraft Interior" volume sliders together as needed.

8. The tips for the spark plug fouling and vapour lock can be turned off by opening the C152's on-screen menu (the little white arrow on the left of the screen), then opening the Refill Menu: the icon that looks like an oil drop.  You can toggle off the simulation of spark plug fouling and vapour lock in there, which will prevent the tips from showing up too.

9. X-Plane doesn't currently have a command for the primer, but the dataref for the handle is "thranda/cockpit/actuators/primer" (0 is fully pushed closed, 1 is fully pulled open).  If you use Lua-based scripting for your home cockpit, you could assign it to that dataref.

10.  Hugo and I weren't able to figure this one out, we don't see where a fuel pump is.  Can you give more details?  X-Plane always tracks whether the array of fuel pumps is running, but the pump for engine #0 (the only engine) is always off.  Where are you seeing a fuel pump?  Thanks!

11.  This is also X-Plane's behavior.  Currently all engines always have exactly the correct fuel mixture for start.  Hopefully this is functionality that will be expanded in X-Plane's modelling in the future.  I agree, real planes are much harder to start than their X-Plane equivalents!

12. The flaps were tuned with the help of one of the JustFlight guys, who went up to do some in-flight testing for us.  When I extend the flaps in the C152 in X-Plane, I get a very gentle pitching moment.  One thing you might do is check your joystick's "Stability Augmentation" settings, and make sure they are all at 0%.

Go to the Joystick settings window and click on the "Control Sensitivity" button at the bottom.  You'll find the "Control Response" sliders on the left (I like a value of about 50% for all three), and the "Stability Augmentation" sliders on the right.  Make sure all 3 "Stability Augmentation" sliders are set to 0%.

Thanks!
--Joseph



Posted By: stephane130281
Date Posted: 31 May 2018 at 12:24pm
Hi Joseph,

Thanks for your reply and the already addressed first points. For me the point 2 was critical to achieve a realistic behavior.

3. I meant with Flaps 10°, sorry for the missing info. In real life, I get 80 KTS, 10° Flaps and 2000 RPM. 2300 is too high according to me.

4.5. I'll recheck those again.

6. What about the steering on the ground? Edit: I ve missed the info that you ve modified it already. Thanks

7. I noticed it by myself in the xplane menu. I was able indeed to reduce the engine sound level. I thought that it would have been possible to do it directly via the JustFlight menu. no big deal anyway.

8. Is there anyway to keep the simulation of the vapor lock and spark plugs fooling ON while not having the tips displayed? I mean, if I turn this option off, I'm missing an important realistic aspect of engine management. The idea is to have it ON, and notice any potential spark plugs fooling while doing the engine run-up and mags check and thus applying the correct procedure in case it is needed.

9. I'm not really familiar with the datareff. Will need to figure out this one. Thanks for the tips.

10. Interesting one! lol
During vapor lock condition, I had the tips saying "turn the fuel pump ON for 30 sec." which is a realistic procedure when the plane is equipped with a fuel pump like the C172R/SP or the C210. As you rightly said, the C152 does not have fuel pump. So how could we get rid of the fuel lock? So I simply used the switch in my home cockpit which is assigned to fuel pump operation from the xplane native function. I was able to hear the fuel pump running and while turned ON, the lock state went from 100% down to 0%. So it looks like the vapor lock react with the use of the fuel pump eventhough there is no fuel pump in the C152. And why asking then to turn the fuel pump ON if there is no fuel pump? That what was weird to me.

11. I understand the xplane limitation there and nothing you can do for the moment (REP does it quite well actually :) )

12. My stability settings are already set to 0% because I understood that it was the correct settings for the highest flight dynamic realism.
However, we are several who notice that extending the flaps from 0 to 10 does not pitch the nose up.
In real life, if you are in downwind, cut the throttle down to 1500 RPM to bleed the airspeed down in the white arc, set one notch of flaps (i.e. 10°), you will notice a strong up pitching moment. I don't see that in the sim, and even the other way around with a slight negative pitch. Same should be observed from 10° to 20°. But indeed, 20° to 30° give a slightly down pitching moment in real life due probably to extra drag rather than more lift.
I'll recheck that one but I m sure of what I ve observed.


Anyway, thanks for the prompt reply that demonstrates a reactive team and a customer focus behabior which is really appreciated as a customer.
I only have experience on the Cessna 172M and the C152 and few hrs on the piper warrior. Any other plane that I buy for the sim, I have to trust the developers statements and flight dynamic model.
In case of the C152, fortunately or unfortunately, it is the largest plane used worldwide and its specific flight behabior is known from almost all real world pilots. So in the case of this plane, it is impossible to miss the inaccuracies of the flight model.

I'm not saying that it is easy. And eventhough it is a simple aircraft, it looks difficult to tune it perfectly in the sim. So I'll understand the flight sim limitations and that it is not possible to tune it perfectly. And in this case I'll accept it, but I won t be able to consider this model as realistic in that case.
The C152 is probably the most challenging plane to develop because it is easy to point out inaccuracies of its flight model :)

Anyway, good luck and all the best and once again, thanks for taking into account our feedbacks. That s really appreciated.

PS: I assume that the updates will be available on the store?

Kind regards
Stéphane




Posted By: Delta558
Date Posted: 31 May 2018 at 1:23pm
Hi Stéphane,

Check your private messages, I replied to you there. Also, I can confirm your description of flap pitching (10 up, 20 up and 30 down because of drag), that's the same description as all other pilots told us during development of the FSX / P3D version and what was created for those sims.

Cheers,
Paul.


Posted By: stephane130281
Date Posted: 31 May 2018 at 4:15pm
Yep I did reply to your PM 😀


Posted By: NoJoe
Date Posted: 31 May 2018 at 4:53pm
Hi Stephane,

Thank you.

And thanks for the clarification on the flaps behavior; I think I had misunderstood your first post. It sounds like the desired behavior is: 10 slight pitch up, 20 slight pitch up, 30 pitch down (due to drag).  I'll write this up internally, but it might be tricky to get.

X-Plane gives us a single set of numbers (lift, moment, drag) for the flaps, and it does its own magic for the different flap settings.  At the moment the way it is set is a compromise, but we'll take another look.

8. Ah, I'm not sure if there is currently a way to keep the fouling and vapour lock simulation running, but without the notifications.  I'll check!

10. Fuel pumps:  Ahhh, thank you, I see what you mean now!  I'll make a note internally to take a look at those messages.  

X-Plane doesn't have the option of "no fuel pump", but we can set it so the pump always defaults off.  But it still is possible to turn on the fuel pump in the background, via keyboard or joystick button.  It can be considered a hidden feature of X-Plane.  :) 

11. Regarding starting of the engine: REP definitely does it very well!  They have created an entirely custom piston engine model, which completely bypasses X-Plane's engine model.  It certainly works well, but it would be a huge amount of work for us to create one as well.  At the moment we're better off sticking with X-Plane's model, given the diversity of engine types we deal with and since Laminar have improvements on the way in the relatively near future.

Cheers,
Joseph



Posted By: stephane130281
Date Posted: 31 May 2018 at 5:15pm
Thanks Jo for the update.
Why JustFlight has no partnership with Simcoders? I mean so far we have to buy a product apart then buy the REP package anyway. So having both in one would raise the price but people will still buy it I think. Just an idea...it s a kind of win win because Simcoders has now a good reputation and justflight is a big producer/developer. Would be the ideal combination!


Posted By: sd_flyer
Date Posted: 31 May 2018 at 9:13pm
Sure guys, ignore answering my questions :) 

P.S. I spun 152 for my CFI initial , so I'm intimately familiar with it. Even though I don't have much time instructing in it I know thing or two :)




Posted By: stephane130281
Date Posted: 01 Jun 2018 at 5:38am
Did not see your question dude!
Center of thrust should be center of pressure which is the average point on the plane where thrust is equally distributed along the aircraft a bit like the CG.
But I m not a flight dynamic engineer tho. That s what my CFI told me to explain the C152 behavior. It makes sense to explain the pitchung moment. Other say it is because of the propeller washes more air around the wings.


Posted By: sd_flyer
Date Posted: 01 Jun 2018 at 12:42pm
Originally posted by stephane130281 stephane130281 wrote:

Did not see your question dude!
Center of thrust should be center of pressure which is the average point on the plane where thrust is equally distributed along the aircraft a bit like the CG.
But I m not a flight dynamic engineer tho. That s what my CFI told me to explain the C152 behavior. It makes sense to explain the pitchung moment. Other say it is because of the propeller washes more air around the wings.

Yeah I think it more has to do with rocket science not aviation. My question; however, was to developers about retrofitting GPS (non pop up), and adding basic IFR capabilities for precision approaches. 


Posted By: Martyn
Date Posted: 01 Jun 2018 at 2:23pm
Currently no plans to fit a new CDI but we will likely add GTN/GNS integration soon.

Martyn


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Martyn
Just Flight Ltd


Posted By: toby23
Date Posted: 19 Jun 2018 at 12:16pm
Originally posted by stephane130281 stephane130281 wrote:

Thanks Jo for the update.
Why JustFlight has no partnership with Simcoders? I mean so far we have to buy a product apart then buy the REP package anyway. So having both in one would raise the price but people will still buy it I think. Just an idea...it s a kind of win win because Simcoders has now a good reputation and justflight is a big producer/developer. Would be the ideal combination!

This would be a fantastic partnership. Just Flight have now proven that they can make THE best GA trainers for X-Plane, aside from the excellent default C172SP, so including REP with the plane seems like a great idea.


Posted By: MartinM
Date Posted: 21 Jun 2018 at 6:22am
Quote 6. Steering is too sensitive on the ground

I think so too. I fly HB-CHA, an F152 in real life and ground handling is way easier than here in the sim. Honestly, the P3D version is more realistic than the XP11 version.



Posted By: stephane130281
Date Posted: 23 Jun 2018 at 9:41pm
How one knows when an update is out? Looking forward for the first update of the xp11 version to be released!


Posted By: Martyn
Date Posted: 26 Jun 2018 at 12:28pm
If you purchased the product from us then you will receive an email notification for any updates. We will also post on various forums and our Facebook page.

Thanks
Martyn


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Martyn
Just Flight Ltd


Posted By: MartinM
Date Posted: 28 Jun 2018 at 7:14am
Originally posted by Martyn Martyn wrote:

If you purchased the product from us then you will receive an email notification for any updates. We will also post on various forums and our Facebook page.

Thanks
Martyn


I got mine via Aerosoft ;)



Posted By: detheridge02
Date Posted: 05 Jul 2018 at 2:53pm
Great news as a number of 152's I've flown have a GNS430 with an ILS capable VOR head for IR(R) training. 

I use the C152 in X Plane regularly (and provided feedback to the FSX/P3D team) to mimic flights I do IRL. Taking into account there's so many models and modifications to the real 152s it's as accurate as you can get in a sim. 


Posted By: stephane130281
Date Posted: 01 Aug 2018 at 8:25pm
When will the update available for the XP11 version please?


Posted By: Martyn
Date Posted: 02 Aug 2018 at 9:46am
It will be available shortly after the Hawk release.

Thanks
Martyn


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Martyn
Just Flight Ltd


Posted By: FlyingSquirrel77
Date Posted: 19 Sep 2018 at 6:33pm
Hi team,

Any news about the update ?

Thanks ! ;-) 


Posted By: stephane130281
Date Posted: 07 Oct 2018 at 3:51am
Hi all

I did a live flight on stream during which I give my opinion on the overall plane:
https://youtu.be/gcS3OqkvCxU


Posted By: roni
Date Posted: 08 Dec 2018 at 4:49pm
Wow, great job stephane130281 in providing such a detailed feedback. 

Is the update still far away? The Hawk was released at the beginning of October.
Martyn, how short is shortly? Smile


Posted By: Martyn
Date Posted: 11 Dec 2018 at 12:30pm
Hi Roni,

Although the C152 update was worked on internally, unfortunately the XP11.30 update came along and introduced many changes and improvements to the core sim (including flight dynamics fixes). We are now working to bring all of our aircraft, including the C152, fully up to XP11.30 standards and we will release an update that includes those improvements as well as any outstanding bug fixes once XP11.30 leaves beta.

Thanks
Martyn


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Martyn
Just Flight Ltd


Posted By: roni
Date Posted: 11 Dec 2018 at 3:14pm
Great news, thanks Martyn!

Looking forward to the update but your C152 is already a joy to fly 


Posted By: stephane130281
Date Posted: 12 Jan 2019 at 12:33pm
Hi all

So now 11.30 official has been released. When one could expect the update to be released?
Thanks


Posted By: roni
Date Posted: 16 Jan 2019 at 4:09pm
Martyn, if you keep waiting XP 11.40 will come along and you know it will also bring many changes and the waiting cycle will start all over again. 
11.30 left beta over a month ago when RC1 was released (RC = no more core changes)



Posted By: stephane130281
Date Posted: 22 Jan 2019 at 9:57pm
I m not even using it. Did fly it for like 10 hrs. Is a refund possible? Probably not but if I don t ask I ll never know...


Posted By: Martyn
Date Posted: 23 Jan 2019 at 9:46am
Hi all,

Following the release of v11.30 on 11th Jan, we have been busy finishing off updates to our entire XP11 fleet (including adding SASL 3.4.2) and those updates are now going through our testing process which won't take long.

Roni - Apologies, I should have said 'left beta and RC' as many changes continued to be made to the core sim as part of the RC stage with multiple builds being released before it was finalised. There's no requirement to await the next cycle of XP11 updates as v11.30 added the changes that we required to address the flight dynamics.

Stephane - We're always happy to provide a refund or exchange if you're having problems with a product. Just get in touch with our support team and they'll sort that out for you.

Regards
Martyn


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Martyn
Just Flight Ltd


Posted By: stephane130281
Date Posted: 23 Jan 2019 at 4:42pm
Thanks Martyn
I m not sure they will refund a product simply because I don t like it!
I ll wait for the update when available before trying to get a refund. I may like it following the changes you ll make based on our feedback hopefully!

Regards
Stephane


Posted By: roni
Date Posted: 24 Jan 2019 at 1:50pm
Thanks for the update Martyn. Looking forward.




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