Spin, Spin Spin.....

[Manhorne]

So, I have been flying the P-47 for about a week now and started trying to dog fight in it for the last couple of days. I am finding it wants to go into uncontrollable spins very easily in turns. Been trying to adjust the curves on my stick to make it a little harder to over pull and put me in spins but have not yet found the best setting. I find it a easy aircraft to just fly around in and do basic stuff but in dog fighting it is very challenging to get the hang of more than any of the other WW2 aircraft in DCS that I have flown....

[Japo32]

that is right. Maybe in VR is easier, but with trackir when looking to sides usually pull too much. Also in takeoffs. Very sensitive aircraft.

[Ironhand]

I may be off base here but it’s my impression from my reading that she’s more of an energy fighter than a turn fighter. If so, tight turns are not her forte.

[Manhorne]

49 minutes ago, Ironhand said:

I may be off base here but it’s my impression from my reading that she’s more of an energy fighter than a turn fighter. If so, tight turns are not her forte.

Yea, You are correct about that. It is going to take me some time to get a feel for turning in it to not want to pull to much. As in a previous quote about TrackIR which is what I am using when turning to the left I more often than not pull to hard and the nose pulls up without me realizing  it and it goes into a bad spin even  though I have not gone under 150MPH. I do not have the same issue turning to the right. I am just going to have to practice much more on my left turns in it . I would imagine it would be easier in VR as the situational awareness would be better.

[Brigg]

Have you put some curves on you axis

[Manhorne]

26 minutes ago, Brigg said:

Have you put some curves on you axis

Yea, I have been playing around with them to see what works best. I had tried them at 20 for pitch and roll but it seemed real sluggish with it there. I dialed it back to 12 and currently have moved them up to 15. I may move them up just a little more and see how that works...

[grafspee]

Watch your speed always.

Power to weight ratio in warbirds is very low.

3g sustained turn rate is almost impossible, after one or two high G  turns you can easily bleed out your energy.

I use curvature about 15 with warthog stick, but you have to be very gentle with stick especially at higher speeds.

[Ironhand]

5 hours ago, Manhorne said:

...when turning to the left I more often than not pull to hard and the nose pulls up without me realizing  it and it goes into a bad spin even  though I have not gone under 150MPH. I do not have the same issue turning to the right...

 

I’m no expert at this but...it might not simply be a matter of adjusting curves.

 

In a roll to the left, isn’t the engine torque assisting your roll? So you’d need to counteract it with rudder. And you shouldn’t be rolling and pulling simultaneously, anyway, I don’t think. Roll to put your axis where you want it, then pull. That should solve the nose rising on you as well.

 

But, then again, I may be completely off base. While I own this lovely aircraft, I haven’t been able to spend much time in her.

Edited December 29, 2020 by Ironhand

[Dragon1-1]

The Jug was known during the war for poor low to medium altitude performance, particularly in turns. It didn't climb very well, either, so Luftwaffe pilots who knew that could and did use it to evade its attacks. Its strengths were dive performance, heavy armament and durability. In right hands, it was a pretty great fighter, and at high altitudes few things could compete with it, but even there, it shouldn't engage in turning contests, because it'd lose more often than not.

[Havremonster]

Not only it spins too easely but it is very slow as well. Today I had no chanse keeping up with a damaged german plane. Felt like I was hunting a jet plane almost. Before I did not have these problems.

[SmirkingGerbil]

She will spin easily due to the torque, always to the left (will pull nose to left, this causes nose wobble for some pilots on landing and hitting power to suddenly), especially during hard maneuvering and hard fire-walled throttle with Water Injection.

You can lessen the this by rolling back on the throttle, especially as you bleed speed. I know this sounds counter intuitive, but to hold the throttle hard forward as you go into a climbing stall or hard G turn and you drop below 200 will almost certainly result in a flat spin of some kind.

 

Ironically, very easy to recover, just pull the throttles back, and counter the spin with your rudder, and once you hit about 180 knots, she will line up straight and you can roll power back on. Very easy to recover from these erratic spins induced by the monster torque of the R2800. You can steer the nose of this plane on gun runs just by working the throttle to get lined up on the target.

Edited December 30, 2020 by SmirkingGerbil

[Manhorne]

12 hours ago, SmirkingGerbil said:

She will spin easily due to the torque, always to the left (will pull nose to left, this causes nose wobble for some pilots on landing and hitting power to suddenly), especially during hard maneuvering and hard fire-walled throttle with Water Injection.

You can lessen the this by rolling back on the throttle, especially as you bleed speed. I know this sounds counter intuitive, but to hold the throttle hard forward as you go into a climbing stall or hard G turn and you drop below 200 will almost certainly result in a flat spin of some kind.

 

Ironically, very easy to recover, just pull the throttles back, and counter the spin with your rudder, and once you hit about 180 knots, she will line up straight and you can roll power back on. Very easy to recover from these erratic spins induced by the monster torque of the R2800. You can steer the nose of this plane on gun runs just by working the throttle to get lined up on the target.

 

I had watched some of the WW2 training films on the P-47 and I know they mentioned some of that. I have found it is easy to recover from the spins. I have not tried reducing the throttle when going into a left turn but I will give that a try. It actually makes sense and I did not think about that as I was more fixated on the target I was after...

[grafspee]

Forget about engine torque and any other things just focus on one thing , learn to fly coordinated this mean that what ever you do keep ball centered.

Once you learn it you can dive deeper, the biggest reason why you spin so easy is side slip in turn.

Once again engine torque is not the only factor which impacts planes, there are 3 other thing. 

Edited December 30, 2020 by grafspee

[Whisper]

All of the DCS WWII birds suffer kinda the same fate, the pitch axis is over sensitive to a very large degree.

I don't use curves personally because it kinda screw up feeling and trimming, so I lower the Y Saturation on the pitch axis, to something in between 65 and 75 for general DCS warbirds, and for the extreme one (the Spitfire) , something like 45 (I'm not kidding... and even at 45, I'm not using the full range of motion, the plane is THAT stupidely sensitive).

People will tell you to adapt and be super precise, but this is shooting yourself in the foot for zero reason, you'll be more precise and won't lose anything in the range of motion of your bird virtual stick, this will NOT hamper any capacity of it in any way.

I've gone for 65 on my free week P-47, it looks fine. I'd suggest to try the same

[CoBlue]

9 hours ago, Whisper said:

All of the DCS WWII birds suffer kinda the same fate, the pitch axis is over sensitive to a very large degree.

I don't use curves personally because it kinda screw up feeling and trimming, so I lower the Y Saturation on the pitch axis, to something in between 65 and 75 for general DCS warbirds, and for the extreme one (the Spitfire) , something like 45 (I'm not kidding... and even at 45, I'm not using the full range of motion, the plane is THAT stupidely sensitive).

People will tell you to adapt and be super precise, but this is shooting yourself in the foot for zero reason, you'll be more precise and won't lose anything in the range of motion of your bird virtual stick, this will NOT hamper any capacity of it in any way.

I've gone for 65 on my free week P-47, it looks fine. I'd suggest to try the same

That's coz you don't have a full length stick. You've got to learn to use curves, 15/15 is a good start. With those I have no problem holding my pitch whatsoever.

Using pitch Saturation will of course lesser your stabilizer travel by 35% in your P-47 & 55% in your Spitt. This WILL effect performance of your plane, especially in slow speed regime. It's like crippling your airplane!

[Whisper]

11 hours ago, CoBlue said:

That's coz you don't have a full length stick. You've got to learn to use curves, 15/15 is a good start. With those I have no problem holding my pitch whatsoever.

Using pitch Saturation will of course lesser your stabilizer travel by 35% in your P-47 & 55% in your Spitt. This WILL effect performance of your plane, especially in slow speed regime. It's like crippling your airplane!

I have a centered, 10cm added Virpil T50

And I guarantee you it doesn't cripple my airplane in ANY way, a huge portion of my stick movement is not used in DCS Warbirds.

 

EDIT : I just re-tested to be sure. Spitfire on the ground, 75 Y Saturation : my elevator still reaches max deflection (easily seen from the outside, the elevator stops moving) before my stick reaches its max. That's why my standard is in between 75 and 65, because the max elevator is in this zone. For the spitfire, on the pitch axis, I go even further because yanking the stick to maximum is the last thing to do in a spit anyway....

Edited December 31, 2020 by Whisper

[Brigg]

21 hours ago, Whisper said:

All of the DCS WWII birds suffer kinda the same fate, the pitch axis is over sensitive to a very large degree.

I don't use curves personally because it kinda screw up feeling and trimming, so I lower the Y Saturation on the pitch axis, to something in between 65 and 75 for general DCS warbirds, and for the extreme one (the Spitfire) , something like 45 (I'm not kidding... and even at 45, I'm not using the full range of motion, the plane is THAT stupidely sensitive).

People will tell you to adapt and be super precise, but this is shooting yourself in the foot for zero reason, you'll be more precise and won't lose anything in the range of motion of your bird virtual stick, this will NOT hamper any capacity of it in any way.

I've gone for 65 on my free week P-47, it looks fine. I'd suggest to try the same

I use a short stick and have just tried this but also put 65 y saturation on the rudder as well. she holds trim in both elevator and rudder way better than the curves. thanks

[msalama]

On 12/30/2020 at 3:57 AM, Havremonster said:

it spins too easely but it is very slow as well

 

And your evidence for these claims is available where exactly? Because you sure don't seem to want to publish it here.

[Mr. Big.Biggs]

Too much coffee???  He’s just voicing his impression.  Back off will ya??? 

[CoBlue]

On 12/31/2020 at 5:20 PM, Whisper said:

EDIT : I just re-tested to be sure. Spitfire on the ground, 75 Y Saturation : my elevator still reaches max deflection (easily seen from the outside, the elevator stops moving) before my stick reaches its max. That's why my standard is in between 75 and 65, because the max elevator is in this zone. For the spitfire, on the pitch axis, I go even further because yanking the stick to maximum is the last thing to do in a spit anyway....

 

NO it doesn't! You can clearly see it in the pics, look at controls indicator at full back stick, 1:st pic is with with no Saturation, 2:nd with 65 Y Saturation. So you're LIMITING your CONTROL SURFACES MOVEMENTS with using Saturation!

Who want's to have maximum pitch authority? I do in ex. dogfights & slowflight.

 

Edited January 2, 2021 by CoBlue

[Havremonster]

6 hours ago, msalama said:

 

And your evidence for these claims is available where exactly? Because you sure don't seem to want to publish it here.

The most stupied I have read in years. Thats all I can say about that. Is this a court or something? I just telling my exsperience!

[grafspee]

On 12/30/2020 at 2:57 AM, Havremonster said:

Not only it spins too easely but it is very slow as well. Today I had no chanse keeping up with a damaged german plane. Felt like I was hunting a jet plane almost. Before I did not have these problems.

Last patch brought up new damage model for radials, if you miss manage your engine power output may drop significantly,. and In p-47 you have to watch your boost and oil temps those things are not regulated automatically. When you over boost detonation may punch a hole in your pistons killing your power very fast, if you under boost main bearing may get damage reducing your power as well.

[PL_Harpoon]

@grafspee Could you share any sources or some more info about the subject?

This whole concept is completely new to me and I'd like to know more.

[Havremonster]

Thanks grafspee. That explain my problem. I will try to be aware of that the next time I fly.

[Diesel_Thunder]

Underboost is not too terrible in itself, but can easily lead to the engine being driven by the prop, which is horrible for the main bearings. Here’s why:
 

With radials, each row of cylinders only has one crankpin. In the R-2800, this means 9 cylinders share one crankpin. One cylinder in the row will have a master connecting rod that connects the piston to the crankshaft, the other 8 in that row will have articulating rods that bolt to the master rod. The key thing here is that all cylinders in a row share the same crank pin. 
 

This is unlike most engines in use today in cars and trucks, where each cylinder has it’s own crankpin. In the case of V engines, the crankpins are typically shared by 2 cylinders. The forces on the crankshaft are reduced because of this, as the bearing surfaces only have to handle one power stroke per revolution. 
 

Back to the radial. Because all rows share one crank pin, that surface has to take the force of 4 or 5 power strokes in each revolution. Nearly all radials have rows with odd numbers of cylinders, 9 per row in the case of our R-2800. This is to help simplify the firing order of the cylinders in each row, which is every other cylinder (1, 3, 5, 7, 9, 2, 4, 6, 8 ). The cylinders are set 40° apart (360/9=40). Every 80° of crankshaft rotation, there is a power stroke in each row of cylinders, and that power stroke pushes on the same spot on the crankshaft. That crankpin takes a lot of force in that one area each time a cylinder fires, and is heavily built for that reason.
 

One other thing that the engine builders did to help those bearings and crankpins stand up to these forces was to drill a hole into the crankshaft that would supply pressurized oil right between the crank pin and master rod at that spot where the power stroke would push to keep the two well lubricated, and more importantly, keep the two from ever touching (metal on metal) and keeping the engine and pilot airborne and happy. 
 

Now, if the engine is at a low power setting, and with decent airpeed, the prop now becomes a windmill and starts driving the engine. Here’s where the problems start. The forces on the crankshaft are now reversed. The crankshaft is pushing the pistons around, and with that the oil hole is on the wrong side of the bearing in this instance. The lubrication on this side of the crankshaft is considerably less, and with the prop driving the engine, usually isn’t enough to prevent metal on metal contact. This is what will wreck the bearings (combat damage not withstanding). 
 

How long an engine can tolerate that is a matter of how hard it is being driven by the prop. High RPM and low power in a steep dive would be more harmful than low RPM and low power in a shallow dive. The key takeaway is not allow the prop to drive the engine as best possible, and to minimize the potential for that to happen. Keeping some power on in a dive would keep the crank shaft loaded properly and mitigate the problem entirely. 
 

Here’s a great link where one could learn more about this with math, diagrams, and an author with loads of experience: https://www.avweb.com/features/pelicans-perch-78-props-driving-engines/

Edited January 3, 2021 by Diesel_Thunder