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Despite many attempts and printing out the guide to keeping the temps Ok, I am unable to keep the temps down to below maximum. I have always had the engine finish up blowing steam on landing even when I don't drop the gear until turn to final and flaps about 20 seconds out.

For instance I just did a flight out of Geelong, started up and taxied out and lined up with the temps around 25%, took off, throttled back to climb at 185 mph and 1000-2000fpm, radiator one click forward of the red mark, and maintained between 180 and 200mph, with the throttle open maybe 1/3, outside temps at ground level 59 degrees fahrenheit, in other words perfect flying weather with the recommended settings, and the temps just climbed and climbed, at just about max temps at 5000' I levelled out and sat on 200mph at around 5000', rpm at around 2000, throttle maybe 1/4, and the temp just kept on rising until it had passed 140 degrees, and a couple of minutes later the engine ran rough and died.

Flight was started with the C172 cold and dark and switched to the Spit before starting.

Surely, surely, this cannot be realistic behaviour?

try between 15000 and 20000 feet at 220 mph and you will find a great improvement in your temps. have you read this tutorial? viewtopic.php?f=77&t=23697

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"He's talking about our mess bills - Sqn Ldr Brian Lane 19(F)Sqn RAF (Having heard Churchill's 'Never in the field' speech)"

Radeon HD 4870 Vapor-X 2GB, Asus P6T, Intel Core i7-920, 3GB DDR3 Memory 1600MHz Windows XP Home Edition.

How much boost are you using? In flight (Cruise) I try to hold the boost under "0" -2/-3 is working fine for me.

Regards/
Stefan

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John,

Firstly, do re-read the radiator tutorial in light of below. (I presume you mean that by "the guide")

Secondly....if you were off by 25% (I presume the radiator temp gauge at 25% of travel, not 25C) did you do the full preflight checks? Usually you should not do these until the radiator gets to 60-70 degrees which is just about 20% around the gauge. By the time you finish these properly the temps should be around 90c.
..around 33% of the gauge.
If not, do you know what mechanical reasons there may have been behind this? Did you check the oil and water before the flight and were they full? These are persistant between flights.

Did you run at normal mixture or lean?

What were the oil temps and pressures during the flight? They should give a clue as to what happened.

How long since last overhaul?

Also, when the temps started to climb, what corrective action did you take? If oil pressure drops a Merlin will last barely 60 seconds. What was your oil pressure when the engine quit? If you boil for long you deplete the coolant and make overheating worse..this affects oil pressure.

Ok, now you say you climbed at 180mph at 1/3 throttle open, so you were using very low boost, high RPM which is NOT at all what the Merlin likes. "Low revs high boost will bring you safely home to roost". 1000 - 2000 fpm is far to low a climb rate. She will do twice that and is designed to do twice that down low. What you are doing is effectively putting a car up a hill in fourth gear at very low speed with it kicking and complaining, rather than changing down and adding more throttle. You are stressing the engine constantly.

So, in summary, the way you have described the flight and subject to the questions above, I would have expected pretty much what you are saying. I suspect you may have started with depleted coolant and maybe too little oil as well. Surely this can't be realistic performance? Well, in a mishandled Baby Spitfire it most certainly can.... The Merlin MUST be flown to the published numbers or you will have trouble. Wet Nursing it will buy you just as much trouble as running it too hard.

regards

Darryl


OK, just tried your setup...best I could get the radiator up to was 110C on a perfectly new aircraft (two hour's flying on the airframe.) I must say too that those speeds, boost settings and climb rates are a devil to fly at... the Spit quite obvioulsy does not like them. I could not hold 180mph and 2000fpm climb with 1/3 throttle open but with 1/3 of boost gauge (about -1, -2, ) I could. Even so, my guess is certainly some pre-existing problem.

In general, get high fast, level off, cruise fast and if a temp problem reers its head, deal with it fast. By the time the temp gets to 130C (and remember the gauge LAGS the actual temp in the engine), your are well on the way to trouble. ALL performance figures and maxima are subject too the overriding need to stay within maximum temperatures.

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Hello,

I also had some problems at first keeping cool, I found that after a hot flight if I didn't make sure the cooling liquid was full before every flight I could get in trouble real fast. So now I check all my fluids before every flight, and as soon as I take off I back off everything and do a nice slow climb, and this seems to work well for me, don't know how realistic it is though, just saying what helps me.

Rockitglider

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Correct,

One word...Accu-sim....if you wouldn't do it in the real aircraft (such as flying without checking oil and water) you can't expect to get away with it in the model.

The Spitfire (particularly the "Babies") simply MUST be flown by the numbers or you are headed for tears. These are not the local aeroclub's C152, they are high performance fighters that were designed for use by professional pilots and with an expectation of daily maintenance (and then with only around 100 hours expected life)

One point though...you may well find that a 2500fpm climb at 2600/2850rpm and boost necessary to maintain 185mph with radiator at Normal +1, may serve you better. If temps spike, level off for a minute, throttle back slightly to achieve, say, 200-210mph at 2400/2600 rpm then climb again.

Fly high, fast and do the maintenance and she is a pussycat to keep cool and to keep in good condition. But having said that, I've had dogfights at between 200ft and 5,000ft lasting 10 - 15 minutes at high power and high G without boiling over BUT you do need to constantly monitor and catch temp rises..just as the pilots had to in 1940


regards


Darryl

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Yeah, once you do everything by the numbers keeping her cool is no problem at all. As I've described in the Flying Tips thread recently: I did a flight from Edwards AFB to Nellis AFB in archived real weather from a quite hot day back in August (OAT on the ground 35°C (95°F) and 37°C (99°F)). While the engine was pretty warm at times (~115° radiator, 85° oil), it never hit the imaginary red lines, even though I spent 8 (Edwards) and 5 minutes (Nellis) on the ground with the engine running.

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Happy Landings
- Patrick

Without having to go into any more detail - that advice works well.

I found that, in the early days, I was "babying" my Spit too much. The moment I switched to getting up to altitude/up to speed *as fast as the limits allow*, I seemed to have much more flexibility.

If your take-off and initial climb are done well - without any overly slow "nose-up" attitudes, then you'll arrive at a cooler altitude fast enough to control the engine better.

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www.nzfsim.org

I hear all of you but I'm still not satisfied that the cooling as modelled is not 'over the top'

For starters the aircraft was topped up 100% and the complete overhaul had just been done. tick for me

Secondly I took off and as soon as practicable after the gear was up increased the speed to 200mph and set the climb rate to 2000fpm, with around 0 boost, which I had to increase to +1 and +2 to maintain a good climb and speed. However the temps just kept on climbing, so I lowered the nose, opened the radiator one notch and throttled back to just keep 200mph, fairly flat, with less than 0 boost, and the temps kept on climbing. So I increased to boost a tad, lowered the nose more and gradually descended at up to 240mph to get the engine to stop heating. It didn't. I then decided to climb, pulled the radiator back to the red mark, and settled into a 200mph climb, at which point the temps steadily rose so the needle passd the 3 o'clock position, the coolant started to leak, and by the time I reached 5,000' the temps were maxxed out and the engine was suffering.

I don't understand the analogy about the high rpm low boost being similar to a car in high gear and low throttle... that makes no sense to me.

I slewed up to 15,000 the other day and flew around and the temps were OK, and with a long slow descending approach the temps still moved into the 140+ zone where the coolant starts leaking. How can that be?

Also, I wonder how the Spitfires that I see on videos and in real life at airshows that take off and fly around for up to an hour or so at low to medium altitudes manage to stay in the air, as they are obviously not climbing as fast as possible to get into the upper cool air.

I would like to be able to replicate these low level sightseeing flights, not climb as fast as possible to 15,000' and stay there until it's time to gingerly descend for a landing.

This is where it would be really helpful to be in the same room with you when you fly the plane however, this comment stands out:
"opened the radiator one notch"

Have you tried opening your radiator all the way for your climb?

Scott.

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A2A Simulations Inc.

John,

I could quote references, studies, trials, biographies, performance evaluations for days, they were all consulted. But it achieves little. 30 years of research, months of development and thousands of hours over hundreds of years total of real pilot experience (including Dudley with real Spitfire hours) went into this model, as well as some of the best programming talent in the business.

For one reason or another you are not achieving typical results. That puts you in a miniority if you are following the tutorials.

I would suggest that we get online and I try to sort this out for you. PM me if you wish to take me up on this offer. I am in WA, GMT +8

A couple, of points though:

You say you opened the radiator a notch when it started to overheat...where was it before then??

A long slow decending approach.....not recommended.

Climbing, with Mk II you should be chasing an RPM of 2850 and speed as per scehdule with a minimum boost of +4 to +9 and taking the resulting climb NOT setting 2000fpm. Mk I 6 1/4 boost 2600RPM.


Most of the Spitfires you see in videos are later, two radiator marques. BBMF Baby Spitfire SOP calls for you to get off the ground within 7-8 minutes, climb and orbit to reduce temps and then start display with an over-riding condition that IF the Spitfire boils, as it sometimes does even with that treatment, the show is scrubbed....

The Temora Spitfires are both later marques where the cooling is much better..although still temperamental.

These aircraft manage to perform in the main as they are flown by pilots with hundreds of hours time on type and thousands of hours total flying.

Anyway, there is no more I can say until I see what you are doing, so please contact me re some online time.

regards


Darryl

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Hello,

I have been experimenting with low level flight and high level flight to see how easy or difficult it is to maintain cool temperatures, and for the most part I can keep the temps below 100-106. Even at low altitudes (below 2000') in different seasons to boot. I've been flying in Summer and Spring as I am tired of everything being white and cold, and I make sure before every flight that I load the correct oil for the season and check the fuel for correct octane, and that all my fluids are full, and I am able to fly low without overheating. I found that an RPM of around 2500-2600 is a good cruise RPM and for boost at low altitude I keep it around -3, if I go to 0 boost to climb and give it little higher RPM then the temp climbs but when it gets a little high for me I just back off the boost a little till the temp goes down the I can add boost to climb faster if needed. I also noticed that if I keep the radiator flap at the normal arrow it seems to keep air flowing through the radiator better than if I open it, this according to the manual creates a ram air effect for the radiator and actually helps it cool better. I just finnished reading the Accusim portion of the manual and am continuing on with the plane manual, it takes me a while to read things as I don't sit and read too long, but I read whenever I can and I eventually finish what I'm reading, and this deffenately helps to operate these planes. I didn't even know what the red arrow was for on the radiator flap lever untill I read it in the manual, I thought it was a bad setting because of the red color. Anyway this plane can be flown low and slow or high and fast without overheating because I'm doing it everyday. I hope you start to get better results as this plane is very fun to fly and the over heating is no fun. The modelling of the heating and cooling may be over done, but since I am not a real pilot and have never even seen a spit in real life I can only assume that these guys and girls knew what they were doing and that itis correct and try to learn how to fly and control the temps as stated in the specs. I love this plane and am looking forward to the P51, I purchased the older P51 for now to mess around with untill the Accusimed version comes out. You will get the hang of it just read more and keep trying.

Rockitglider

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The P-51 will no doubt be marvellous fun and certainly had none of the Spitfire's overheating problems due to a better arrangement for radiators.

It is a sad fact that the revolutionary design of the Spitfire wing, which gave such great performance also led to a bundle of problems (cooling, narrow track, gun warming problems, gun jambing problems, heavy aileron controls at speed, to name a few). Later changes to cooling pipes and radiator size (Mk VC) helped relatively little, but made the bigger, hotter Merlin 45 a little easier to manage (and the 45M down low), The dual radiator setups on the VIII and IX were the first time that cooling efficiency approached parity on the ground and the shutters were, interestingly, made automatic so as to overcome pilot error and reduce pilot workload. This makes them popular aircraft with modern restorers and at airshows.
Various methods are used these days to keep Warbirds cooler and Dudley can talk with much more authority on those than I.

When the wing was almost totally redesigned (and really, a 22 or 24 is not a Spitfire in ANY conventional sense of the name) these cooling problems were finally laid to rest.

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...