Warhawk

[Ivan]

Hawk 87W - Update

There hasn't been much activity on the Hawk 87W (P-40N) but there has been some.

The SCASM processing is now complete.
This means that further texture updates will be much simpler because the files are BMP format.
The animation changes are also complete.

One thing that has bothered me for a while is that the low speed handling of the P-40 seemed to be too good.
There appeared to be way too much control authority.

My task over the last couple days was to adjust the low speed control without compromising the generally excellent handling.
After creating spreadsheets to graph the control effect versus aerodynamic force (1/2 Rho V^2) and making adjustments,
I found that what I arrived at for new values was not significantly different from what is currently in place.
In other words, it appears to be pretty well tuned (or where I want it to be) now.

There was one area in which the values were different; My new values for Rudder Effect were a bit lower at low speed.
The question then becomes: Is the Rudder Effect too high or is the Propeller Torque Effect too low?
In any case, the Low Speed Rudder Effect is only noticeable if the Tail Wheel is made free castoring instead of steerable which means that in the actual flight model with a steerable Tail Wheel it is invisible.

The other minor change is to test a different texture pattern on the Spinner.
The later model P-40 especially when used by the RAF, RAAF, and RNZAF had a tendency to use two colours there.
The texture is a bit harder to apply than usual because it is Fore-Aft instead of Left-Right.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
Sounds as though progress is being made!

At least you have done something, wheras in my case I´ve been totally inactive - with the German course for waiters there´s no energy left for building aircraft. The timetable is two hours daily at midday and it gets in the middle of cleaning, cooking and lunch and I´ve got a kind of buider´s block"! Perhaps when the private students have their holidays as of June or July I´ll have some free afternoons to pursue FS building.

Regarding the steerable tailwheel in FS, I find the way it is controlled in the opposite direction so confusing that I prefer not to have it.

Cheers,
Aleatorylamp

 

[Ivan]

Hello Aleatorylamp,

Actually I have been working on other projects.
Some are even CFS related.
You might have seen my thread in "Other Hobbies".
There are a few things in that direction that needed pursued.

- Ivan.

 

[Ivan]

Under the Knife

The Technicians and Test Pilots have been working on a little project with the P-40N which has finally come down to a matter of fine tuning.

Several of the staff were on the Me 109E Trop project and used that aeroplane to experiment with directional control parameters to try to fly a "Knife Edge". The lessons from that project were added to the P-40N where they are working as expected.

The screenshot shows the P-40N maintaining altitude though drastically losing airspeed while doing it.
The adjustments are needed to lower the amount of airspeed that is lost so that this maneuver can be flownfor longer.
Note the low airspeed and extreme yaw angle.

- Ivan.

-

 

[aleatorylamp]

Hello Ivan,
Wow! I believe the Germans call it the "hammerhead".
It is a very intriguing manouever, this one, how to have the fuselage and vertical stabilizer as sustaining surfaces... totally mind boggling!
Cheers,
Aleatorylamp

 

[Ivan]

Flight Model Updates

It seems like CFS Superchargers have a bit more capability than I had thought.
Aleatorylamp came across an interesting supercharger power reduction by adjusting a parameter identified as

WEP Pressure Change Rate (0.528 or Zero)

This parameter apparently works as modifier to the SuperCharger Boost Gain parameter.
If set to Zero, there is no additional power when using WEP above the critical altitude.
By doing this, the high altitude WEP effect which was causing problems is gone.

Unfortunately, the testing also showed that the parameters which were modified to allow knife-edge flight affected lateral stability and control in a very unfavourable way so until I can compensate in the AIR file this feature will not be included.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
I´m glad that regulating the WEP Pressure Change Rate has cured the P-40´s excessive WEP effect at altitude, and hopefully you´ll find a way of correcting the knife-edge lateral stability side-effects!
Cheers,
Aleatorylamp

 

[Ivan]

The P-40N didn't have the greatest problems with WEP at altitude; The P-40K and P-40E were quite a bit worse.

The P-40K also has a new visual model which may the excuse for an updated release.

In playing with the P-40N, it just did not look right without a shark mouth, so the last couple evenings were spent in repainting the cowl to put a shark Mouth there.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
The Sharkmouth is definitely an asset for this model!
Cheers,
Aleatorylamp

 

[Ivan]

Climb Performance Testing

Last Night, I ran a test of the P-40N's Climb Performance.

Results are the following:
Best Climbing Airspeed is around 195 MPH TAS.
Yes, I know it varies in IAS with altitude.

While holding 195 MPH TAS, Climb Rate was
2800 feet / minute at 500-1,000 feet altitude
2885 feet / minute at 5,000 feet altitude
3000 feet / minute at 10,000 feet
3085 feet / minute at 12,000 feet

At 5,000 feet, 195 MPH works out to be about 180 MPH IAS, so that is the number I will use for record.
The climb rates seem to be where I would have wanted them.

The plan is to test again using IAS at some point to find the Indicated Air Speed at which I can get the best climb rate.

- Ivan.

 

[Ivan]

Service Ceiling Test

Starting with 55% fuel the P-40N Service Ceiling appears to be
32,700 feet with 509 HP at 293 MPH TAS which is pretty close to 180 MPH IAS.
Remaining fuel was 64.3 Gallons (73.5 Gallons would be 50%).

Absolute Ceiling appears to be just over 35,050 feet with 442 HP.

Unfortunately for me, I started this test fairly low at 27,500 feet, so the actual test took much longer and burned more fuel that I expected.
The Service Ceiling is a bit higher than I would have wanted, but this was done with autopilot.
A manually flown test would probably end up a bit lower but also would be a bit harder to reproduce.

I will probably repeat this test at some point to try to have it finish with 50% fuel.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
Thanks for this useful information. It comes in very handy for my Baltimore Mk.V and MkIIIA/IV tests.
Cheers,
Aleatorylamp

 

[Ivan]

A second test of the Service Ceiling gave 32,400 feet with about 71.5 gallons fuel remaining.

Climb Rate specifications seem to vary quite a lot depending on the test conditions.
A test report of the P-40N-5 running at 44 inches Hg showed only a bit over 2200 feet / minute.
A test report of the P-40N-1 running at 57 inches Hg showed 3100 feet / minute.
My own test of my "P-40N-15" at 52 inches Hg gave about 2800 feet / minute which seems quite in line with the actual test reports.

It has been uploaded.

Hello No Dice,
You wanted a P-40N for your birthday a couple years back.
This version is either a few years late or a month or so early.
I will send you a copy shortly.
(Anna Honey says I need to prep for some guests now.)

- Ivan.

 

[aleatorylamp]

Hello Ivan,
A very nice quality-contribution, this long-tail, and a great flier too!
This time I was careful on take-off and my pride was left intact!
Cheers,
Aleatorylamp

 

[Ivan]

Thanks Aleatorylamp.

I liked the way it turned out also.

Next step is to go back and finish up a P-40M which should not be difficult and also to rework the P-40E and P-40K flight models.
Then there are the P-40C models..... The list is endless.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
It´s turning out to be quite a unique collection!
Aleatorylamp

 

[Ivan]

am in Cambridge, MAssachusetts at the moment and on an iPad.
Not going to be on much for a few days.

- Ivan.

 

[Ivan]

Version 011 contains an updated AIR file.
There are no performance changes.
The Aircraft Type Identification has been changed.
The Length specification in the Description has also been changed.
(The earlier version listed the length of a Short Tail Warhawk.)

- Ivan.

 

[Ivan]

Long Tailed Merlin

A while back, after receiving an email about No Dice, I was thinking about how he always had a way of giving praise for the projects I had released.
I went back and found one of the old threads: The one that described the Merlin P-40F, my latest project at that time.
As usual, he had some nice compliments.

I followed the thread a bit and my plan at the time was to work on a proper Long-Tail P-40 and then build the Long Tail versions of the Merlin P-40. I had actually gotten pretty far as detailed in THIS thread.
The P-40M was completed but not released because I could not decide on a good paint job.
The P-40K was also worked on though I cannot remember where I left it.
The P-40N was completed and released and even had an immediate update for an error in the description.

I never actually went back to the Merlin P-40.

A few months ago, on another forum, there was a very long running discussion about the merits of the Merlin P-40 and its relative performance as a fighter against its contemporaries. There was quite a bit of information presented and some of it resolved some contradictions that I had encountered when working on the original version of the flight model.
These discussions and the old thread "Ivan's Latest and Greatest" were the reason behind this latest round of updates.

The updates turned out to be quite easy.
The model updates were lifted from the P-40N; The longer tail was designed specifically so that the pieces would match easily to the current version of the Short-Tail Warhawk.
Texture updates were tedious as usual, but not as bad as they could have been because with the design of the Long-Tail, the textures were arranged so that only one mapping edit was needed and only one texture needed to be edited (in theory).

Attached are some images of the completed textures as applied on the model.
There are more images and historical information in the thread mentioned earlier.

- Ivan.

 

[Ivan]

New Propeller

As part of the updates to the flight model of the P-40F, I thought it would be a good idea to manufacture a custom propeller to replace the current propeller which probably came from the stock P51D.

None of the P-40 projects that I have released thus far have had anything but a stock propeller with all of its problems.
Doing a quick comparison showed that just about all the P-40s had pretty comparable propellers with only small variations because of engine output and critical altitude. The only real exceptions were the Merlin equipped versions which used a different reduction gear ratio.

With this in mind, it made more sense to build a propeller that was best suited for the Allison P-40 and adapt it to the Merlin as was probably done in real life. The P-40N was selected as the development aircraft because its flight model was the most recent and least likely to have other problems.

The First screenshot shows a speed run after testing to determine engine output at each altitude.
370 MPH @ 12,500 feet with 1351 HP on Military Power.
370 MPH can also be achieved at 10,000 feet with 1479 HP on War Emergency.
Critical Altitude is 12,850 feet.

Second and Third screenshots show current Propeller Tables 511 and 512 which have the standard Perpetual Motion curves.

- Ivan.