SOH P-61 project

[warchild]

I imagine one will need to pay attention to fuel and payloads before flight - so as not to try to land

what is the optimum approach speed in the Lady - and how is the 'mush' factor near stall speed?

what min. runway length is recommended both for max payload takeoff - and for landing rollout (hopefully with low fuel and no ordy)

Welll, As you say, handling is very dependent on weight and speed.. Until i made my last adjustment to the pitch rate damping, there was little confidence to be had with landings. With a normal loadout, anything below 150 mph and she wallowed like a pig.. if you watch part three of the training film, you'll see the real planes nose bob up and down about 5 feet. ours was doing the same thing. She became touchy and hard to control at slower speeds, and i'm seriously concidering taking her back to where she does that again.. At higher speeds she's practically like a surgeons scalpel. She rolls fast and will pull into a 6G pitch in a heartbeat. Turning wise, she's more than a match for almost anything. In a climb her weigh works heavily against her. the props will pull her up well enough, but gravity is a major factor there.. The only two types of combat this plane would be excellent for would be a diving attack, and a turning fight. Anything else and you can kiss it goodbye.. But then, thats why they made the top turret rotational .. Theoretically you can counter a maneuver while keeping crosshairs on him; theoretically.. truth told, in its one year of life in the army, the plane never found its niche. Jack Northrop designed an amazing plane with the P-61. it may have been designed as a night fighter, but theres more to it than that i think. her final days saw her working mostly on intruder ( attack ) missions, blowing up trains and other strategic objects, which with the firepower she had, she did amazingly well.. At the moment, out plane mimics the real one in flight ( according to all the data we've been able to gather ). Takeoff is fairly normal with just a slight yaw to the left, and she settles like a rock when you raise the flaps.. But once your up, she flies good. Landing can be tricky. the plane wallows as said, and stability isnt the most assuring thing you have, but youve seen the video. You can bank all the way down to the runway and still level her out to touch down.. Stopping is done in a little over 980 feet.
one thing is for certain. She isnt one of these light and nomble type planes you can dance all over the sky like a jumping bean.. Like Tom said above. Shes heavy metal thunder. Fast, heavy, and god pity whatever found its way in front of her canons. Our plane will be just like her

PS:: Optimum approach speed is 110 with touch down at 95 - 100 with a mostly full load.
Takeoff dist was approx 2000 feet with a full load and flaps, and 2000 feet with a light load and no flaps..

[heywooood]

same TO distance regardless of load....@ 2000'

I would like to see a P-61 fly - I go up to Chino once in a while and if anyone who frequents these boards ever gets a chance to go for the Planes of Fame Museum and flight displays they put on - do yourself a favor and just go you wont be sorry...it sure would great if they got their hands on one for a weekend

[PRB]

Rgr on Chino! I've been to a few of those air shows.

During the 1980s, there used to be an annual air show at the Madera airport (KMCE?) It was always a fantastic war bird display. Well, one day a week or so before one of those shows, the local Fresno AM radio station, KMJ, had, as a guest, one of the organizers of the show. Ray Appleton, the local talk show guy, is a war bird nut too, so he has this guy on his show and they're talking war birds, when the subject of P-61s came up. This organizer guy said “there was one scheduled to be at last year's show, but it had an engine fire, in flight, on the way from San Francisco.” Rays eyes got all big, and mine did too, and he wanted to confirm we were talking about P-61s. “Yes”, the organizer guy said, “P-61.” I still don't believe it. This would have been mid-1980s, and I was P-61 fanatic even back then, and I can't believe a flying P-61 would have escaped my attention during this time.

[warchild]

regarding takeoffs.. yeah, its the flaps and weight. The flaps produce up to 70% extra lift ( the zap flaps produced up to 90% ) which is why with a heavy load you can still take off in a relatively reasonable distance. With a light load, you can take off in rather short distances. However, when you raise the flaps, all that extra lift is lost and you sink a couple hundred feet as the plane picks up speed and accelerates to where it generates the extra lift on its own.. The downside to the flaps is that they act like the worlds biggest airbrakes. The training video advises you to wait till your below 150 mph before extendong the flaps to the first step. Theres a reason. The army tried an experiment using dive brakes on the C model. The brakes had a habit of ripping the wings off and they werent even half the size of the flaps.. If you use flaps to land, you will need to use full throttle and a relatively steep decent in order to maintain airspeed. I'll use about 45 degrees like you saw in the video. You also lose some stability with the flaps. These flaps are not slotted and there's no space between the leading edge of the flap and the trailing edge of the wing for air to escape, so you end up with this massive amount of disturbed air under the wings. Makes the experience feel a little like flying on bacon grease.. Kinda slippery.. She wants to roll but it isnt too difficult to counter. Just apply a small amount of counter force on the stick till you raise the flaps or land..

As for Chino, i wish i had been there.. P-61's have been a favorite of mine since i was very little.. Big, strong, and powerful as all get out. It was a mans machine. a pure brute of a monster. One of them was even named "Rolling Thunder". She was like the World War Two version of the F-4, and before anyone rips me a new one for saying that, the F-4 didnt exactly start out as the most capable player either.. She was an attack craft, a gunship and a fighter all in one; one of the original intruders along with the A-26 and b-26 Marauder. Yup.i'm really sorry i'll never get to see one up close..

[fliger747]

AT 32,000 lbs (full load is around 37,000 lbs) takeoff run was 2,600 ft. For the P-61B, the bomber loading was 36,908 lbs. Interesting that for the long range fighter that the useable oil was up to 600 lbs vrs 330 lbs for the normal fighter. It was a feature of the R2800 powered aircraft that they had a large oil tank in the nacell aft of the acessory section. At the lightest weight, 26,000 lbs to run, 1600 ft.

The joke of my friends who used to fly radial engine aircraft was to land and fill the oil and check the fuel..... How to tell if a radial is out of oil... it's not leaking....

Cheers: T

[warchild]

The joke of my friends who used to fly radial engine aircraft was to land and fill the oil and check the fuel..... How to tell if a radial is out of oil... it's not leaking....

Cheers: T

::ROFLMAO:; i've heard those somewhere before. Probably at an airshow or something.. There's definitely a word of truth there ::LOL::..

Gotta admit though, with her takeoff distance, it kinda makes you wonder what they considered a short field takeoff ..
The runways on Le Shima were 4996 feet in length and i'm getting off the ground with normal load and half flaps in about half that distance which would put us somewhere in the ballpark i think..

[fliger747]

Flaps are described as a single slotted type, (hunnert thou p-394, 395) certainly not a multi articulated Fowler type, but still much more effective at large deflections than say a plain flap. Many Cessna's that I have flown, 150, 152, 170, 172, 180, 185, 206, 207, including ones with the Robertson kit have a very similar (and large) flap assembly. No particular buffeting was noticable such as would be noted with large deflection of a plain flap. The high pressure built up under the flap also resulted in a very high energy added to the top of the flap through the aerodynamic slot at the top.

Because of the large span, the increase of CL/drag at smaller extensions would be quite good, giving superior turn performance.

Cheers: T

[warchild]

interesting.. Let me do some more research and see what the POH days. Not that it'll make a diference, but i do hate it when my information is incorrect..

[warchild]

I just went up with Delta558 for a bit, and we did a lil formation stuff 9 at which i suck ) and a lil dogfighting ( at which i suck even worse ) and had a great time. but during the course of the dogfighting, everything we've talked about on here came true.. The plane is a team participation plane because once your opponent is behind the engine, youve lost him. You need the gunner and radar operator to keep your eyes on them.. Hi yo-yo's will get you killed.. Gravity doesnt like you in this plane and it will try and drag your butt down to the earth.. High G turns and dives work amazingly well, and if you lose sight of your opponent, you can hit the WEP and run away ( skimming treetops at 400 mph is a lot of fun ::lol: ).
Theres a lot of potential in using online for testing with a test plane and a chase plane.. I'm liking this a lot..

[fliger747]

Some of the data that I have for Naval aircraft lists very detailed takeoff distances (wonder why this was an issue?). I suspect that somewhere detailed test data exists for the P-61. The graph on page 382 (hunner't thou) is fairly good, but not quite as valuable as the tables I have seen for other aircraft.

To test takeoff distances I use ISA conditions, somewhere close to SL. At dusk you can pause the takeoff at liftoff and in external view count runway lights which are 200 ft apart. I think we are pretty close, but am experimenting with the gear drag to see if I can extend it about 200 ft.

Cheers: T

[warchild]

I never once thought about using runway lights. What a great idea.. thank you.. i always end up finding the runway length then going into overhead view and measuring where i am on the runway.. its a lot more of a rough estimate than your method.. Gonna try yours ..

[fliger747]

Be interesting to evaluate it against some of it's contemporarys such as the Mosquito, F7F-N and JU88. Against some of the Japanese planes it probably had enough speed and diving ability.

Cheers: T

[warchild]

I agree.. it would be very interesting.. With its ability to out turn an F6F we know it can out turn a zero, but i dont know how it would fair against a mosquito or a hornet, or even a BF-109.. It would be fun to find out ( provided someone more experienced with dogfighting than me is flying it )..

I've been combing through the POH ( p61BlackWidow.pdf ) and have caught a couple things that raised an eyebrow.. The biggest raise i got however was from the reported maximum allowable RPM during dives.. 3060 RPM.. i dont know how we can model that, but i'd like too if possible..

[fliger747]

Still getting a bit shorter to dist than we should, by 200 ft or so. Pilots operating handbook doesn't say much about TO flap settings, except for "use 20 deg if time permits" for a scramble TO. Says consult appendix 1, which we don't currently have.

One way of doing this might be to reduce thrust and drag equally to preserve flight speeds.
Cheers: T

[N2056]

Robert, (N2056)

That looks really amazing :salute: Is there a Sperry A3 autopilot beneath the main flight instruments? That black panel looks like a Sperry A3 surround, especially with that 3rd gauge (Suction?) hole.

Thanks, and yes...that is the autopilot you describe. I hope to get it all working in 3d :d

[fliger747]

Pam:

Working on the thrust/drag and think this might be a productive line. Adjusted both a bit and it does increase the TO dist to about the right value and still maintains proper flight speed.

Did a low altitude snap roll yesterday, a bit wild, looked like an elephant ballet....

Will try to shoot you another FDE this evening:

T

[warchild]

::LOL:: an elephant ballet eh? ::LOL:; sounds about right..
I've been working on temps and pressures as usual, but got to thinking about wights as well.. The more i think about it, the more i'm inclined to the idea of keeping the empty weight to its absolute empty weight of a little under 21000 pounds. The military loadout is good though, so if we stuck to the low end empty weight, would that imply we would nee a load out manager?? The lower empty weight gives us a take off at exactly 110 mph, which is still 10 mph fast but acceptable.. Also with the lower empty weight we're able to achieve an in flight speed of 351 mph on just military speed and no wep which jives with most of the documentation ive read.. Still though, finding a programmer for a load manager isnt going to be the easiest thing to do..

[fliger747]

Pam:

The 21,000 lb weight does not include any installed guns, armor, oxygen, gun sighting stations. Page 383, table 54 shows how these weights break out. 24,414 lbs is the empty weight with all the normal military equipment for a Bee. That does not include ammo etc. Easy enough for folks to go change the consumables and fuel loads in the FSX airplane fuel/payload tab.

Currently with 20 deg flaps it goes flying nicely at 85-90 knots, (89-103 mph) seems about right. The tko speed has to be with flaps as a look at the stall speeds clean indicates.

A plane that needs energy, think we are doing pretty well with this so far!

Cheers: T

[warchild]

Ahhh.. ok.. now i understand. thank you .. still though, we could most likely use a load manager.. well, in time..

[fliger747]

Pam:

Indeed, a load manager would be great and add a lot. if someone here has the ability to do one. Been futzing with the plane a bit. Switched it to my computer that has the dear departed Aircraft Container Manager (Mangler). Looks pretty good. Added some scrape points allowing it to be bellied in and moved one cockpit VC light that was 15 feet in front of the nose (needed a minus sign).

We could include the military equipment into the load items, I have done this before for those wanting to fly a "warbird" with all that weight thrown out.

Cheers: T

[warchild]

i've been fine tuning trim deflection and response. Getting it to be a bit more usuable.. I'm still not getting exact 0 yrim but i'm close now.. Moved the eyepoint up an inch and a half so we can barely see over the top of the bar that rns the lngth of the canopy. moved the center of lift 1.5 inches in front of the CG to better facilitate trimming stability while maintaining the documented nose down effect in turns ( nose should drop almost 90 degrees in a 180 degree turn).

Pissed off at AFX and instant scenery, but i'm probably not in a minority there.. Been flying the lady since i woke up this morning and am just gonna find a better terrain mesh for okinawa and go fly some more.. this plane's getting real comfortable to fly..

Gonna post some portraits of some interesting paints we can vote on as places to begin.. Naturally, i want "lady in the Dark" cuz well, thats the story of my life right there :;chuckles:;..

[warchild]

thought id post these for everyone to vote on. it aint all of them by a long shot, but its a start..

[warchild]

and some mre

[fliger747]

Just screwing around and it flies and shows just fine in FS9! moved the main wheels a couple of inches aft. However as we are dealing with possibly different models, stay with your contacts except you can keep the scrape points for the belly landing if you want.

Pilots were generally not impressed with the P-61 cockpit visibility, my guess it was beacuse of the long nose. The F7F had a very slim sloping nose by contrast.

Cheers: T

[warchild]

Just screwing around and it flies and shows just fine in FS9! moved the main wheels a couple of inches aft. However as we are dealing with possibly different models, stay with your contacts except you can keep the scrape points for the belly landing if you want.

Pilots were generally not impressed with the P-61 cockpit visibility, my guess it was beacuse of the long nose. The F7F had a very slim sloping nose by contrast.

Cheers: T

cool.. will look forward to adding your numbers to mine.. We're getting close.. I mean really close..
in the online flight i did with delta558 today, cockpit visibility was a major major drawback.. i didnt figure out till later that i could have switched to the gunner view and it would have been a much better viewpoint.. if your reo or gunner were stoned drunk or asleep, you would be dead meat...

you might eant to download the newest VC from the file browser. The filename is 29aug.zip. N2056 has been doing an incredible job on the gauges. my only concern is regarding the prop.. the actual prop used was a full feathering variable pitch prop made by curtiss electric, but, fsx doesnt support variable pitch that i know of, so i made it a constant pitch prop. This gives us a nasty side effect, in that the engines rpm is directly governed by the pitch of the prop while in flight. i did a small test and opened the prop controls and dropped the pitch then raised it again.. As the pitch came down, so did the rpm's as i raised the pitch the rpms came back up.. contrasting that, in flight, if i change the throttle setting, nothing happens to the rpms. they stay pegged at 2700 rpm. however, so much of what goes on in this plane is governed by rpm settings its not funny.. We could change out the prop for a fixed pitch prop, but there goes feathering. i just dont know what we can do.. any ideas??/