Thanks everyone, really appreciate the kind words. I'm working hard to make this airplane as good as I possibly can.
Aww, just for you then Pam: test flights this afternoon near China Lake, CA, checking for any texture or modelling errors in bright sunshine with HDR lighting onOriginally Posted by warchild
I wish I had enough time to finish writing everything I sta...https://www.facebook.com/DC-Designs-2156295428024778/
Wow! Looks awesome!
Wow! Looks awesome!
Yep, it sure does
Looking forward to trying this out
Pete.
Bada BUMP...
-- WH
If at first you don't succeed, try, try,try again. ... or go read the manual.
I'll see your BUMP and raise you an UPDATE!Bada BUMP...
Sorry for not posting more recently, I've been hard at work polishing things off with the Reporter and getting rid of graphical niggles. It will be released as a BETA very soon and is being tested as we speak. Some images of the aircraft taken this morning are below - I've coded for pilots to disappear when the battery is off and other little additions since learning a bit about XML
A picture of Robert Stack with your all caps UPDATE!! would've been epic, but these pics will do! Looks fantastic!I just picked up the In Action book (in full color nowadays!) for the P-61 which includes the C model I never knew about and the Reporter. The way the rear steps retracted on the F-15 was pretty nifty with a crew member only needing to step on a plunger once on top of the plane. Looking forward to taking her around the patch!
It just keeps getting better.. Thanks for the update. It's nice to see how these progress.
-- WH
If at first you don't succeed, try, try,try again. ... or go read the manual.
SaWeet!!! Can't wait to have it in the hangar!
@DC1973,
are you using a Spec file texture as well? how about a Fresnel?
MACH 3 DESIGN STUDIO
Heatblur Rivet Counting Squad™
Was entry by an external ladder or up through the nose wheel well between the seats..?
There was an external ladder that opened on the left side of the aft fuselage. Last man up stepped on a plunger on top of the fuselage and it closed! It may have also kept the boarding ladder in the nose wheel well.
external ladder built into the port aft section of the tail..
Yup, a specular on the main fuselage metal, a Fresnel and then slight "pitting" of the metal via the alpha channel for the bump maps to give the metal some depth. I used the same Fresnel but reversed it for the canopy texture, so the glass reflects more evenly without going all blue when beneath a cloudless sky.
Pam's right - a rear boarding ladder was fitted on the aft port fuselage. I haven't modelled this however at the moment.
Love the period (short) when the props started looking like early jets which soon evolved. Also anything powered by an R2800!
For my part. I added the internal 500 gallon fuel tank: adjusted the fuel flow for cruising range of 1900 miles @ 360 mph ( cruising speed ) with max ferry range @ 4300 miles with external tanks ( to specs ): Adjusted the viewpoint and CG: Softened the brakes so you dont fly through the windscreen when you step on them: Changed the propellers out for standard propellers instead of the big paddle propellers used on the P-61B&C: Adjusted the thrust to give us 400mph @ Sea level which should give us the requisite 440mph @ 27000 feet: and tested the planes ability to land @ 80mph for short field work. admittedly, it's a hair raising experience landing that slow, but it does it..
Left to do?? I have to get the rpms down from 2900 to 2700. Test and adjust to make sure the aircraft is developing 1hp for every 6.6 pounds of weight. Those will keep me busy for a little while..
missing information: Take off distance, landing distance.
Since this thing is developing so much power so quickly ( about like using a draft horse to pull a laptop out of a ditch ), the takeoff roll is much shorter than the P-61.
Pratt&Whitney report this plane as using their R2800-73 engines. These are 2800HP engines initially used on the P-61C and the first engine produced by Pratt&Whitney to produce 1HP per Cubic Inch. I'm doing my best to ensure we get thee correct performance for that engine.. Anyway. I'll keep you updated..
Pam
Graham Whites "R2800" lists the -73 as a 2100 hp takeoff and mil power, with the 2100 available up to 28,500', an impressive performance! It however does not mention use of water injection which would be necessary for the 2800 hp. It does list a landing speed of 93 mph. The -77 engine only differed in the ignition system used.
It does note 440 mph at 30,000 ft. As this would be "dry" power it doesn't have the built in WEP time limit imposed by FS. Impressive for such a large plane!
You may have some confused information there. The Original F15A prototype was based on a P-61A that was chopped down and converted to a two seater F-15. It had originally been slated to be built as a fighter ( The P-61E ) but was cancelled with the end of WWII, and reincarnated as the F-15A prototype which sported a 2000 HP Pratt and Whitney R-2800. Only one was built. The remainder of the RF-61s were P-61C conversions using the 2800 HP engine.
There was a technologie difference fom the R2800-63W to the R2800-73, and I desperately need to find the web site with the history of the engines designer and design progression, because what i'm about to say is simply extraordinary leaving the burden of proof in my court.
The R2800-73 didnt use WEP, BUT! Well, The fuel for the model 73 was 115 octane with a lot of lead. This helped cool the cylinder heads, but wasnt enough to win the in house competition against the R3600 team ( the corn cob ). Yeah, thats right, the 2800 HP R2800 was the result of a competition between the two design tams, only the R2800 chief designer was bloody crazy. Still at one horse power per cubic inch ( a record the R3600 team never achieved ) even he knew when he had reached the limits of the technology. Besides the 115 octane fuel, there was an ethanol mixture, but it wasnt fired directly into the cylinder. It was fed in with the fuel. The mechanism they used to accomplish this metering is diagrammed in the PDF located here. https://ww2aircraft.net/forum/thread...engines.37875/
Here's the biggest issue. The only people with anything even close to canon information on these engines, seems to be Pratt and Whiney themselves. Even the changeover from numeral nomenclatures to the C and CA nomenclatures appears to confuse people and there is a great deal of understandably innocent misinformation out there. Why Mr. White lists the 73 as a 2100 HP engine, i do not know. Several sites, including revolvy ( https://www.revolvy.com/main/index.p...tem_type=topic ) list the 73 as being the subtype which developed 2800 hp using water injection and a General Electric CH-5-A3 turbocharger. What is possible is that Mr White misread the data, as the model 83 produced 2100HP. and the distance between a 7 and an 8 when making a deadline, is very short. It is very possible he made a typo, and didnt realize it, then continued to use the data for the model 83 without knowing he'd made a mistake.. Still, more sites cite the model 73 as being not only 2800- HP but the engine used in the F-15A than not.. ( https://www.revolvy.com/main/index.p...tem_type=topic )
Whites 950 page book seems to be the definitive work on the R2800, not only do they have specs for every model, there is a chapter on every aircraft that used this engine, including the P61-F15A series.
As far as I can tell "No Production, aircraft installed R2800 reached 2800 hp without water meth injection". Methanol cannot be used in aircraft engine fuel for various reasons, even "gasohol" or "Heet" for fuel anti icing. It's a problem for aircraft such as my Super Cub that have an Auto Gas STC, making sure that the gas has no alcohol in it.
Meeting the speed performance figures with the lower HP is not an issue in FS, but will result in a slightly lower acceleration and climb rate.
My guess as to why it did not have Water injection? Appropriate regulation of the turbo charger which would have to do a lot of thinking in an era when machines did not think much. Development of such systems could be very troublesome and time consuming. Time was a luxury during the war.
: )
Quote from one of your sources:
- Powerplant: 2 × Pratt & Whitney R-2800-C Double Wasp 18-cyl. air-cooled radial piston engines, 2,100 hp (1,600 kW) each
Oh no, please forgive me. I was incorrect if i mentioned methanol.. It was very early in the morning you see. No, the engine used water/ethanol but rather than injecting it into the cylinder directly, it was fed in as metered fuel. Thats why its so important that i find that website that was there when we worked on the P-61 and has since disappeared. It goes into how they did it..
Heh.. I'm sitting here with Squadron Signal's P-61 Black Widow open to page 76 where it shows the F-15A-1 Tail number 559303, and at the same time i have all these other windows opened up all over the place.. The caption for the F-15A-1 reads " The production F-15A-1 Aircraft differed from the XF-15 by utilizing the same engines and cowls as the P-61C." And the image indeed shows P-61C Nacelles attached to this F-15A-1.
If we go to http://www.aviation-history.com/northrop/p61.html and scroll down too the P-61C section, it states:
P-61C
The P-61C was essentially the same airframe, but with more powerful turbosupercharged R-2800-73 radials offering a max WEP of 2,800 hp (2,088 kW). It was heavier than the A or B models and was said to be less maneuverable. Exterior differences of the XP-61C were a large air scoop under each engine and paddle-bladed A.O. Smith propellers to take advantage of the increased power.
As too how the engine developed power without direct water injection into the cylinder I believe the answer is in the lower right corner of the below image showing unmetered fuel ( Avgas ) and metered fuel ( water/ethanol ) going through the same control unit.
I think your correct about the supercharger, but i'm no expert. The main bearings played a very large part in power production and engine temperature as well. Again though thats part of that missing web page i cant find.. I do know that when the germans acquired an R2800 that P&W had a heart attack. The bearings were a top secret alloy compound and they were terrified the germans would find out.
Regarding Whites, It may very well be the definitive publication on the R-2800 But even God made a mistake once. However, there is one more detail that we may not be considering and White may have. After the war, as surplus planes and engines entered the civilian sector FAA regulations demanded that the military grade superchargers be removed. I dont know why. I always thought it was terribly unfair. With the F-15s, that would mean an entire change out if i'm correct which is where the 2100HP version may have been introduced. I dont know. I'm guessing here..
Pam.
(Edit) Correction on the fuel: The RF-61 FAA Type Certification lists the fuel used as being 130 Octane.
Graham Whites "R2800" $83.00 new?? Dude. I cant afford that..
The way the water methanol injection worked was to meter it through the carburetor. Injecting it into the cyl would not work. The methanol was there to keep the water from freezing, it was not really as a fuel component. The water introduced into the intake manifold vaporized and considerably cooled the mixture, allowing a greater mixture density, making the supercharging more efficient, allowing more fuel and air on each intake stroke. The water also cooled the internal flame temperature slightly, allowing a leaner and more stocimetric mixture, yielding greater power than with the too rich mixtures normally used at high power settings. The water also increased the mass flow through the engine and carried a lot of waste heat out through the "tailpipe". After all heat transfer via cooling fins, out the tailpipe and through the oil coolers was really the limiting factor for potential engine power.
The P61A had an R2800 -10 which was also used in the Hellcat and was fitted with WEP as a -10W in the F6F. Some A and B series aircraft did have water injection (10 W engine), with 24-36 gallons on board, good for 15-20 mins of use.
The -73 and -77 engines were also used in the P47N and with water injection were capable of limited 2800 hp at 72" MP, but had the same 2100 HP at 54" for Mil Power. (Hundred Thou pg 281). So far no definite indication that the Reporter had Water injection, and some indication it did not, but if I do find it I will pass it along.
: )
That would be greatly appreciated Tom.. Thank you..
For the purposes of the initial release however, I'm leaving them at 2800 HP. The biggest reasons for this is plain and simple fun factor Copmbined with an exceedingly short ( and apparently ever shortening ) list of available data to draw from. I also didnt have any tools when i first started this project. What i did know from the various books in my collection as well as various other sources, was that the P-61C developed 2800 HP, and the f-15A was based on the P-61C using the same wings and engines.. I can easily model WEP into a second FDE and offer it as an option for those who want reality. The end result remains the same with a 360 mph cruise speed and a top speed of 440 mph. The F-15A was an amazing plane no matter hopw you looked at it. Fast, Sleek and more nimble than her somewhat heavier progenitor, the P-61C. It's only fault was being created at the wrong time in history.
Have you tried putting the web address into the wayback machine?
https://archive.org/web/
America's Hundred Thousand and also "Northrop's Night Hunter" have some data on the various models of the P-61, but seem to fall off the planet when it comes to specifics about the Reporter.
No info is no info, so currently any case can be made. The water injected C models could carry up to 531 lbs of water/meth plus whatever the associated equipment weighed. That's a lot of weight! It is possible that a recon aircraft might be better off without the weight, being able to go higher and faster and further? I don't know. Heinemann who designed the A4 and many other famous aircraft had a philosophy for that project of "Simplicate and add lightness". An extra pound of basic weight required stronger structure, bigger engines, more fuel, which kept spiraling. His assertion was that an extra pound resulted in ten.
Only 500 -77 engines were built in total, all by Chevy.
Did they toss out all the weight they could and rely on cleaning up the airframe for the 440 mph or are they relying on the water injection to achieve that speed only in a sprint? Unlike the real world, once we set the HP and thrust, we trim the drag to get the proper speeds.
Sure it will be a fun flier!!
Members who have read this thread: 1
Posting Permissions
FSX
Bookmarks