Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: F4UDOA on July 18, 2001, 10:53:00 PM
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Gents,
In light of the coming changes to the flap model of many AH fighters I would just like to ask this question.
How long is the virtual flight deck of the AH carriers? I still auger at least 50% of the time when taking off with a full load in an F4U-1D with 100% fuel 2 1k eggs and 8 rockets.
Takeoff run from the F4U pilots manual. Weights of materials from Americas Hundred Thousand
Max weight15,000lbs= 12,000 100% fuel/ammo+ 2 1,000lbs bombs + 8 rockets weighing 1,155lbs.
54inches MAP<==only
30 degrees of flap<==can use 50degrees for shorter run
25 knot headwind
Takeoff distance required====>700FT!!
This is the single best example of the Flaps not providing enough lift.
Anybody want to take a guess at how long the AH carrier deck is??
The lenght of a Midway class carrier in WW2 was 968FT. (The USS. Franklin)
Essex Class= 874 (Bunker Hill etc)
Enterpise, Hornet, Yorktown= 761Ft
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1 word about flaps being fixed...
fowler
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One thing to consider is that we don't start from the approach end of the deck. In other words, I don't think we can measure how much "runway available" we actually have.
I'd guess Pyro would have to tell us.
Additionally, I think the carrier is moving at more than 25 knots but I don't know if that Headwind effect is modeled into the takeoff portion. You know how you get that additional rate of climb at some altitudes? I never see that effect when becoming airborn off a carrier.
I'm not arguing anything for or against here, just making a few observations.
BTW, F4, I truly admire the way you ask for changes. Always with some data, ALWAYS polite and never in a "non-stop" constant manner.
<S>
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The carrier is an Essex-class (long hull) that moves at 33 knots. Flight deck length is listed as 888 feet for the long hull. I figure a takeoff run of 700 feet would be about right, perhaps a smidge more or less depending on deck crowding.
Specs from www.warships1.com (http://www.warships1.com)
-----------------------
Flakbait [Delta6]
Delta Six's Flight School (http://www.worldaccessnet.com/~delta6)
Put the P-61B in Aces High
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I'm gonna go out there and remove one of His creations from this universe.
And when I get back I'm gonna drink a bottle of Scotch like it was Chiggy von
Richthofen's blood and celebrate his death."
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(http://www.worldaccessnet.com/~delta6/htbin/delta6.jpg)
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Originally posted by Toad:
One thing to consider is that we don't start from the approach end of the deck. In other words, I don't think we can measure how much "runway available" we actually have.
of course you can. Go into H2H with a friend, let him slowly roll to the end of the runway and watch the distance in his icon until he "disappears" :)
Additionally, I think the carrier is moving at more than 25 knots but I don't know if that Headwind effect is modeled into the takeoff portion.
watch your speed indicator when you spawn...
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We don't get a full roll. To get a Hog off the deck fully loaded like that, first just touch your throttle so the auto-brakes disengage, and let the plane roll back. Once you are almost to the end of the deck, then set your brakes, raise your flaps, throttle up, WEP, and let her go. Yes I said raise the flaps. :) The drag is definately modelled, so don't start dropping the flaps until you have to... ie: as you pass the superstructure. After that let her settle level, don't raise the nose... you'll make it, but not by much. Make sure you raise your gear the instant you clear or you'll never make it.
But the question about lift from flaps is still a valid one. Back in beta I did some tests... I think it's time to re-do them and see if we can quantify the lift from flaps. What should extending flaps do... allow us to maintain level flight at a slower speed? Is that a valid test?
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Thanks Toad<S>
I always look at the airspeed indicator before I take off. I also try to make sure that the ship is not making any abrupt maneuvers. However I augered three times in a row the other day and it really got me pissed so I did some offline testing. The Carriers at speed have 25MPH accross the deck during a standard takeoff. And your flaps if they are to work at all now have to be deployed at the last second or they will slow you down, and then only 2 notches seems to actually help. Keep in mind that a real carrier takeoff didn't require the pilot to give 100% power from the start. They fed the power in and still made the launch.
I think the current drag penalty for flaps is to high but also they are not producing anough lift noticed by the A/C that use flaps not stalling at the correct speeds.
The Carrier is simply the most frustrating.
Cit,
I think you will see a benifit to the low drag of the fowler when modeled however keep in mind that the P-38 at 17,000lbs did not have a very low stall speed even with flaps. Not bad but not that low. Around 85MPH CAS. Of course that should improve with lighter weights.
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Heya Lephturn<S>
We posted at the same time so I didn't see yours before I put my last one up.
Anyway yes that is a valid test. In most A/C flaps will lower the minimum flying speeds(F6F). In some A/C they can be used for maneuevering(F4U) and some the flaps where made for maneuvering(p-51, P-38 and sorry the NIK2).
In the case of the F4U ground run testing was very important and like most planes minimum ground run testing is listed in the Pilots operational manual which I have three of. One being P-47N, yes the P-47N!!. I got it at an Airshow recently.
P-47N
16,300lbs
54inches MAP
2800RPM
20 degrees flap
35knot(40mph) headwind
Takeoff run = 1625ft
So taking the stall speed of these A/C and then lowering it according to the CAS (Calibrated airspeed) chart in the flight manual should give you the stall with full flaps(power off usually). Then for partial flap deployment it is a little tricky but still very logical. It requires some calculation be done of the CL max with full flaps and devide the increase in lift by the number of notches of flap available to determine how much lift should be gained from each notch of flap. Then the correct stall becomes easy.
Anyway I'll get off my soapbox now. :D
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So as far as the 38 and the f4 (fowlers)is concerned it will turn better, the stall will be better and the e retention from engaging the flaps will be better...? Sounds like a win win situation to me :)
Wow... any idea WHEN we can expect to see this newer version?
xBAT
[ 07-19-2001: Message edited by: batdog ]
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1 thing alos is we dont get the benifit of turning the CV into the wind, so we ae missing 10 to 20 knots of lift speed there also.
F4UDOA what did they do for plane that didnt get the whole deck to run on, some planes only got half or less to run on when the were full of planes for missions.
whels
Originally posted by F4UDOA:
Gents,
In light of the coming changes to the flap model of many AH fighters I would just like to ask this question.
How long is the virtual flight deck of the AH carriers? I still auger at least 50% of the time when taking off with a full load in an F4U-1D with 100% fuel 2 1k eggs and 8 rockets.
Takeoff run from the F4U pilots manual. Weights of materials from Americas Hundred Thousand
Max weight15,000lbs= 12,000 100% fuel/ammo+ 2 1,000lbs bombs + 8 rockets weighing 1,155lbs.
54inches MAP<==only
30 degrees of flap<==can use 50degrees for shorter run
25 knot headwind
Takeoff distance required====>700FT!!
This is the single best example of the Flaps not providing enough lift.
Anybody want to take a guess at how long the AH carrier deck is??
The lenght of a Midway class carrier in WW2 was 968FT. (The USS. Franklin)
Essex Class= 874 (Bunker Hill etc)
Enterpise, Hornet, Yorktown= 761Ft
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i rarely auger F4U with 100 fuel 2 1ks and rocks loaded. i can back up like Leph says but usually idont. i pop up, hit shift + for 100% trottle, P for wep. and as i get to the end of the deck i pop 1 notch flap, asi leave the deck i very lightly pull back on stick and raise gear imediaely.i pul on stick just enough to keep it from hitting the
water which it will do if u let autotakeoff
do it all.
whels
Originally posted by F4UDOA:
Thanks Toad<S>
I always look at the airspeed indicator before I take off. I also try to make sure that the ship is not making any abrupt maneuvers. However I augered three times in a row the other day and it really got me pissed so I did some offline testing. The Carriers at speed have 25MPH accross the deck during a standard takeoff. And your flaps if they are to work at all now have to be deployed at the last second or they will slow you down, and then only 2 notches seems to actually help. Keep in mind that a real carrier takeoff didn't require the pilot to give 100% power from the start. They fed the power in and still made the launch.
I think the current drag penalty for flaps is to high but also they are not producing anough lift noticed by the A/C that use flaps not stalling at the correct speeds.
The Carrier is simply the most frustrating.
Cit,
I think you will see a benifit to the low drag of the fowler when modeled however keep in mind that the P-38 at 17,000lbs did not have a very low stall speed even with flaps. Not bad but not that low. Around 85MPH CAS. Of course that should improve with lighter weights.
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Whels,
Actually you do get the benifit of the headwind. Check you speedometer before takeoff. You will have about 25mph indicated.
I am sure there are techniques to get you off of the deck, however my reason for posting is that there shouldn't be a need for a special trick. It is what the A/C was meant to do and did very well with the use of flaps.
Batdog,
I think you will see marked improvement in the P-38 and it's use in the MA. But you asked a very good question. When is this fix going to get here??
Pyro?
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F4UDOA,
what i mean is, we are missing the exta wind from headwind above the normal ships speed.
In RL not only did they have the 20 or knots of ship speed but also would turn into the wind for launch for the extra wind speed also
and we dont get that in AH.
whels
Originally posted by F4UDOA:
Whels,
Actually you do get the benifit of the headwind. Check you speedometer before takeoff. You will have about 25mph indicated.
I am sure there are techniques to get you off of the deck, however my reason for posting is that there shouldn't be a need for a special trick. It is what the A/C was meant to do and did very well with the use of flaps.
Batdog,
I think you will see marked improvement in the P-38 and it's use in the MA. But you asked a very good question. When is this fix going to get here??
Pyro?
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you can get the hog off every time by using full flaps even without wep....
snatch the gear up as soon as you get off the deck... after all the gear is used as an air brake too right? :)
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Cit,
You take 100% fuel, 2 1K bombs and 8 Rockets and I gaurentee you won't make it off the deck. WEP or not. The flaps make it impossible to get enough speed to take off.
Kind of the exact opposite of what is supposed to happen ya know :)
BTW I do take the gear up ASAP.
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DOA,
I can get off the deck 100% of the time with that load. Here's the film
http://www.iaw.com/~general6/f4u_carrier_takeoff.ahf (http://www.iaw.com/~general6/f4u_carrier_takeoff.ahf)
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DOA I agree with you that the flaps do not seem to be generating enough lift and you have data everytime to prove it.
BUT, I can get the hog up with 2 1k bombs 8 rckts and 100% fuel everytime without a problem.
1. Start engine
2. Kick off autotakeoff (YES I AM A LAZY DWEEB!)
3. Apply full flaps
4. Throttle full and hit WEP
5. As soon as she clears the end of the deck gear up.
6. Wallow her almost to water level and start to climb.
7. Bring the flaps up
8. As speed climbs hit auto climb speed
:) :)
Works for me everytime. I usually can get 100mph +/- as I cross the end of the deck even with full flaps.
My landings aren't as pretty tho :)
S!
Rocket
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F4UDOA yea I hope it does improve the 38. The question is will it really improve me,LOL. It cant hurt as I am a rabid turner in the 38 to a point of idiocy, ;)
I dont think Pyro and those guys ever even hinted at a date, I think he stated something like it'll be out when its out more or less. They have a huge platter this upcoming version I think so are most likely busy as heck.
xBAT
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Since they are going to change the flap model, are they going to fix the climb and e-retention problems you were also able to identifiy F4UDOA? Still looking for that zoom ;)
Zippatuh
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Batdog and Zip,
I think all our hope are tied together on this one. The climb/acceleration(not really e-retention) on the -1D and the underweight -1C are supposed to be fixed according to Pyro at the same time he does the F4U-1 early and the F4U-4. I swear he said it in the MA. And since part of the problem is the stall as it relates to the flaps I guess you would have to say that all of those issues would be tied together. This will also affect the P-51B/D and possible others including the NIK2. Unless Pyro breaks out the flap/stall issues away from the rest of the FM problems with the -1D.
How nice would it be to be able to accelerate at a respectable level in a D hog when fighting a Yak or a NIK2 on the deck. How nice will it be to see more P-38's in the MA instead of a constant diet of NIK2.
We can only hope
:)
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Hope... yeah.. hope.
Btw, to get off carrier with fully loaded hog just hit brakes till rpm's up, WEP it without flaps till you almost off the carrier, hit 2 flaps just before the jump.. on the jump retract gear and let the plane fall a bit, retract 1 flap before hitting the water.. and level. Works every time.
Remember, the trick is to not look down ;)
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F4UDOA, the USS Franklin was an Essex class carrier. The Midway class included the FDR and the Coral Sea.
Razor
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hmm 8 Rockets and 2*1000lb bombs would be a total weight of 15320lb
If 15000lb is the maximum weight, then you can assume that they didnīt fly with full tanks.
Furthermore you have on the runway a ground effect for the lift, which is missing immediatly after you left the carrier deck.
Thereīs a note in you pdf-document about the take-off distance from carriers. The page is labeled "performance comparison of various CV current and future airplane", Note 4. I canīt read it 100%, maybe it is helpful. What does it say exactly?
Climbrate is correct for the FU4 at the moment! But the F4U is 10mph to fast over 3k so enjoy your speed advantage.
niklas
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Niklas,
15,000lbs is the highest weight listed in the Pilots manual not the max takeoff weight. The loading I took from America's Hundred thousand so I know the weight for the rockets is correct. The loaded weight for the A/C varies depending on source. Some are just under 12,000lbs and some are over. 15,000+ a few hundred pounds is good enough for me ;)
As far as the climb goes I have multiple documents that put the initial climb of the F4U in combat condition at 3300FPM+.
Check these docs of the F4U-1 with prop blade design 6443
F4U-1A (http://www.geocities.com/slakergmb/id63.htm)
Against the F4U-1D with Prop blade design 6501A-0
F4U-1D (http://www.geocities.com/slakergmb/id71.htm)
I have several docs that confirm a improvement in climb with the use of the latter blade design.
Including the F4U test against the FW190A-5, P-51B and the pilots manual where it states that the 65501A-0 improves climb and performance. It is the same design as was used on the F4U-4 except in a 4 blade prop. It was three inches shorter and wider ala the paddle blade P-47.
I also have the chart for the F4U-1 with the new prop blade. It is here. Notice the Mil poser climb is much better that the AH charts?
F4U data (http://members.home.net/markw4/MSWF4UDATA.pdf)
As far as the AH F4U being to fast I'm not sure what you mean. It seems to match the AH charts posted pretty closely?
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Here's the setup:
F4UC, 100% internal fuel, 2*1000lb, full rocket setup.
On the deck, I hit toebrakes, then rev up engine. I hit wep as I release toe brakes.
Lift off, gears up - NO USE OF FLAPS.
Film:
http://stsantas.tripod.com/film89.zip (http://stsantas.tripod.com/film89.zip)
This is the first time I fly the F4U for - god, many months, since tour 3 - and I get it off even without using flaps.
I make a nice landing too, except the plane starts going backwards and rolls into the sea :).
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I have been flying the F4, mostly so I can do carrier ops. What mistifies me is that sometimes you can take off with ease and at other times it is pretty darn hard.
I use the same technique each time!
My technique is:
100% throttle + P
Let the tail raise itself
2 flaps when passing super structure
Correct left wing dip at launch
Gear up
Wings level
Get speed
Dodge the battleship
Ease flaps up
I notice that it at times it will just not fly at launch, but just sinks into the sea. (An F4 floating is amazing in itself ;) )
One time it is relatively easy and the next time it is near impossible. Any clues?
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F4UDOA, i have seen all these documents before.
You should slowly begin to have a closer look at the docs.
The clue is in your PDF Document, where you can see that 2250HP is only possible near ground due to the RAM effect. There are several pages (labeld bhp comparison) in you pdf-document where they decide between
- brake horsepower in climb
- brake horsepower in high speed
- rated bhp
If you study them you will can see that the REAL bhp for a slow flight/climb doesnīt exceed ~2050hp near ground, wheras - as already mentioned - due to the RAM effect you can get in a fast flight near sealevel 2250hp. But ONLY in a fast flight.
Ok, your first 2 links lead to pages with a nice hmmm letīs call it "Error". Because they take the rated bhp curve. You can further see a nice contradiction in these docs. Because in ~15k, the critical altitude for topspeed is ~2k higher than for the climb - which is correct, RAM effect. But near 2k, the critical altitudes are the SAME which is wrong. Here they simply neglected in their performance chart the real bhp.
You wonīt be able to show me a takeoff power number (slow flight...) with more than 2000hp btw....
BTW those docs and numbers were published in late ī45 after the war, where you can assume that they already had the new propeller.
I hope you understand what i mean, else i will post some pics.
To your P51-F4U test: Sry, but this test was done by the NAVY and the whole style of the test let come up in me the impression (even the first time i read it) that the whole purpose of this test was to have at least on the paper a NAVY fighter which is far better than the best USAAF fighter.
Written for the navy lovers, for someone like you...
Navy and USAAF didnīt like them very much, right ? :rolleyes:
niklas
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Here's something else you can try F4UDOA ... the patented 'Tom Blackburn' takeoff method.
Engine to full power, hit WEP .. NO FLAPS!
Just as you are about to run out of deck, drop one notch of flaps and rotate, sucking up your gear as quickly as you can.
Flaps may not generate sufficient lift at present, but I seem to recall from my (admittedly limited) F4U flying that the drag from the flaps was enough to prevent sufficient takeoff speed. Starting your roll with no flaps gives you max acceleration down the deck .. dropping one notch on rotation gives you that marginal bit of lift you may need to stay airborne :)
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Niklas,
The engine was rated at 2250HP. I'm really not sure what it is you are questioning? It is not the only source for that rated HP. And all A/C benifit from the RAM air effect. Especially those with Turbo-charged engines. It certainly doesn't mean that it shouldn't be modeled in AH?
As far as the prop change, I don't have to guess when that took place. It was the end of 1943 into 1944. Just look at the back of the documents for the F4U-1 and -1D. It list the prop blade type. And like I said in the FW190 and P-51 flight test it mentions the benifits of that prop over the previous versions. As well as a note in the pilots manual saying to use the 65501A-0 whenever possible as it "increases performance".
So what is inaccurate about my data?