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Flight model and other early impressions


AcroGimp

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The flaps are split flaps so pure drag, no lift

Don't agree. Split flaps usually have a slightly higher delta CLmax than plain flaps and even various Yak-52 manuals quote significantly lower stall speeds with extended flaps.


Edited by bbrz

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Haven't flown the 52 (very unfortunately), but I've experienced this behavior with other light single engine aircraft (Cessna 162, Cessna 172, etc).

There must be some kind of misunderstanding since the Yak-52 and a C172 can be easily trimmed for hands off flight without the need to apply constant forward/aft pressure.

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I wasn't talking about after it was trimmed. Of course it can be trimmed easily not to do that, otherwise it would be a horrible plane to teach students lol.

The point is that Reflected said that he needs to apply constant forward pressure. It's interesting that the Yak-25 pitches up since most low wing planes tend to pitch down with flap extension.

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Interesting. Even with only 25% fuel I can't keep 160km/h with full flaps in level flight. Only 150-155km/h so drag does seem to be excessive, especially given the rather small size of the flaps.

 

No need for full nose down trim. Trimming fully nose down I get here up to 350km/h with gear and flaps extended.

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Yak flaps are very draggy, as is the gear when extended - especially with prop set fine/high RPM - it will take a fair amount of power to maintain level flight at 150 kph if configured.

 

For the overhead, I break at 250-ish kph, decelerate on the downwind, gear at 200 kph to hit the perch at 170 kph with gear extended usually at 1600' MSL (1,200 AGL), I will drop flaps and initiate a dogleg to the runway - typically have to add a little power past the 90, prop full forward on short final, touchdown at 120-ish holding nose wheel off.

 

I have only made one landing so far in the DCS Yak, it was a normal landing, not the overhead, and drag/performance seemed close, nothing stood out anyway as grossly incorrect.

 

So long as the identified issues get addressed this will be a fun and useful module with real training value for formation since it lacks the kind of gross excess power the tactical aircraft have - makes you learn the visual geometry, patience and airmanship that 'easier' aircraft will not teach.

 

Should be very good for formation acro IF/when fixed since the real plane is fantastic for it.

 

 

'Gimp

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A-4E | F-5E | F-14B | F/A-18C | AV-8B NA | UH-1H | FC3 | Yak-52 | KA-50 | Mi-8 | SA-342



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FAA Comm'l/Instrument, FAST Formation Wingman, Yak-52 Owner/Pilot

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Yak flaps are very draggy, as is the gear when extended - especially with prop set fine/high RPM - it will take a fair amount of power to maintain level flight at 150 kph if configured.

 

Just tested and at pattern altitude, 840mmHG, prop 100% I'm seeing with

gear and flaps up 285km/h, gear down 265km/h, gear and flaps down 165km/h.

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So long as the identified issues get addressed this will be a fun and useful module with real training value for formation since it lacks the kind of gross excess power the tactical aircraft have - makes you learn the visual geometry, patience and airmanship that 'easier' aircraft will not teach.

 

All good AcroGimp, these aircraft are living breathing pieces of algorithm art. Testing, tuning and adjusting is always necessary at this level of sim modeling.;)

Change one thing and many other things can get worse, it will take a little time.


Edited by David OC

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Download PDF Tutorial guides to help get up to speed with aircraft quickly and also great for taking a good look at the aircraft available for DCS before purchasing. Link

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Full flaps, 150kph. 40 litres petrol left. Full stick forward. Still going up.

 

Did the model for the second pilot have a few too many burgers or something?

 

 

Nose down trim got it back in line but I had me finger on that button for a surprising amount of time.

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Full flaps, 150kph. 40 litres petrol left. Full stick forward. Still going up.

Did the model for the second pilot have a few too many burgers or something?

 

I don't believe that. Even if the second pilot eats all the burgers while extending the flaps, the CG shouldn't noticeable move. :lol:

 

Seriously. I definitely don't need full forward stick to correct the pitch up. Doing that, even at 170km/h results in a -0.9G push over.

 

Trimmed clean for level flight with 170km/h I need ~ 50% of the available nose up trim, and level flight at 150km/h with gear and flaps down requires a bit less than 50% of the available nose down trim.


Edited by bbrz

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Due to the moment arm from sitting about 6 feet behind you, a GIB (guy in back) makes a substantial impact on cg and is most noticeable in the resulting pitch sensitivity. With a light pilot and heavy GIB you can get to the edge of the envelope Aft, especially with the old Russian avionics gear still behind the back seat.

 

The pitch snatch/snap becomes far more prevalent if you ask too much of the wing but most importantly stick force per G gets VERY light which leads to more accidental excursions into the snatch/snap behavior.

 

There is way more pitch authority in those massive tailfeathers though than would be needed to overcome any out-of-trim situation clean or configured - it might take a heavy push or pull but my experience is the trim is marginal and can always be overridden by the pilot.

 

The speeds reported by @bbrz all sound about right although I can easily get 250 kph in level flight at 82% RPM and maybe 700-ish mmHg, happens when we have a T-34 leading and they let the plane run out a little - we keep formation speeds at 200-220 kph to give a power margin to whoever is on the outside.

 

'Gimp (DISCO vVMFA-122)

[sIGPIC][/sIGPIC]

A-4E | F-5E | F-14B | F/A-18C | AV-8B NA | UH-1H | FC3 | Yak-52 | KA-50 | Mi-8 | SA-342



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FAA Comm'l/Instrument, FAST Formation Wingman, Yak-52 Owner/Pilot

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Due to the moment arm from sitting about 6 feet behind you, a GIB (guy in back) makes a substantial impact on cg and is most noticeable in the resulting pitch sensitivity. With a light pilot and heavy GIB you can get to the edge of the envelope Aft, especially with the old Russian avionics gear still behind the back seat.

Nice info and exactly the reason why I opened a new thread: https://forums.eagle.ru/showthread.php?t=217450

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All good AcroGimp, these aircraft are living breathing pieces of algorithm art. Testing, tuning and adjusting is always necessary at this level of sim modeling.;)

Change one thing and many other things can get worse, it will take a little time.

 

THIS, the module's been in the wild less than 24 hours, LOL Awesome feedback from the OP but coding and debugging takes time. I just went through the entire early access period for the Spitfire and the flight model is like night and day from the first week. She now behaves as described in the historical manuals and by real world pilots but it took over a year.

 

My flight experience consists of a couple hours in a Cessna and glider but I sure had fun flying the Yak. It is nice to know she is being developed to a standard that will be useful for real world training. A Yak-52 and Christen Eagle are a much more realistic possibility for myself and most people to actually be able to fly IRL. There's a guy a couple hours from where I live who rents out a tandem Spitfire for rides but it will set you back several thousand dollars. A Yak or Eagle are actually "affordable".

 

 

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  • ED Team
THIS, the module's been in the wild less than 24 hours, LOL Awesome feedback from the OP but coding and debugging takes time. I just went through the entire early access period for the Spitfire and the flight model is like night and day from the first week. She now behaves as described in the historical manuals and by real world pilots but it took over a year.

.

 

I love your experience, but I have to say that the FM was not changed from July 16 when it was approved by Nick Grey in Duxford. Some minor tweaks was of course made but all of them were before the early access release.

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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be patient guys, its early access ... if you bring emotional facts to the table, understand that you're talking to a programmer, he needs numbers, not feelings :)))

Su34 & F111 a dream fullfilled in fsx...[sIGPIC][/sIGPIC]

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I love your experience, but I have to say that the FM was not changed from July 16 when it was approved by Nick Grey in Duxford. Some minor tweaks was of course made but all of them were before the early access release.

 

Really? I changed up my controller curves a bit on Chuck's suggestion and got better at trimming her out, but maybe it was just placebo effect. She seemed to have gotten more stable over time especially take off and landing. I fly every version of the Spittie on PC, Mark I-IX on different sims. It starts to become a blur.

 

Loving the Yak so far :thumbup: I read so many silly comments on why DCS was doing another trainer that it almost became comical.

 

The developer that publishes DCS: Cessna 172 is going to laugh all the way to the bank.

 

 

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...

 

The developer that publishes DCS: Cessna 172 is going to laugh all the way to the bank.

I saw what you did there ....

Su34 & F111 a dream fullfilled in fsx...[sIGPIC][/sIGPIC]

i5 5600, 1050ti, 16 GVram, win10 , TM W hotas&rudder, waiting for 1060/1070 price fall or a new gpu family..f*&9 miners :)

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I don't believe that. Even if the second pilot eats all the burgers while extending the flaps, the CG shouldn't noticeable move. :lol:

 

Seriously. I definitely don't need full forward stick to correct the pitch up. Doing that, even at 170km/h results in a -0.9G push over.

 

Trimmed clean for level flight with 170km/h I need ~ 50% of the available nose up trim, and level flight at 150km/h with gear and flaps down requires a bit less than 50% of the available nose down trim.

 

 

Figured out why...

 

 

Full forward on the controller wasn't giving me full forward for some reason. ;/

 

 

 

Still a bastard of a snatch up leading to some surprising stalls on landing.

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Figured out why...

 

 

Full forward on the controller wasn't giving me full forward for some reason. ;/

 

 

 

Still a bastard of a snatch up leading to some surprising stalls on landing.

 

How so? you mean the stick? I have the same bug with the trim: I set it to a slider, and the slider only moves it 50% towards each extremity.

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When rudder trim works as intended will it be possible to dial in a speed where she flies with no slip, "ball centered"?

 

I'd guess it'd be around 200 km/h

 

First off, there is no in-flight trimmable rudder on the Yak-52, it is a fixed tab so it is only ever truly 'in trim' at one speed. For most Yak's in the US this is set at 110 kts (~202 kph) because that is our typical formation sortie speed that gives us plenty of performance margin.

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It sure does seem to flare up with the landing flaps down on final. It caught me off guard the first time, and I actually had to do a go-around, but I landed without incident on the second try! I'm liking the module so far, and I am excited to get a buddy into the backseat.

Fire only at close range, and only when your opponent is properly in your sights.

 

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