Help with fast climb - can't break 15 minutes to 20,000 ft

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Styggron
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Help with fast climb - can't break 15 minutes to 20,000 ft

Post by Styggron »

Hello everyone,
I've been trying to do a fast climb to 20,000 in the spitfire to simulate Battle of Britain Scramble Procedure, (KillRatio challenge) and can't ever seem to break the 15 minute mark. Obviously I am climbing incorrectly.

I went through the Spitfire Manual but could not find the Vy speed for the best angle, pitch, speed etc to get to 20,0000 feet as quick as possible.

When I tend to do is build up speed and just pitch up, then pitch down a little to build up more speed then pitch up again etc.

Anyone have the Vy speeds ? for the models A2A have ?
I fly the IIb generally.

Thanks everyone.
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Jacques
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Help with fast climb - can't break 15 minutes to 20,000 ft

Post by Jacques »

Hi Styggron,

The Mark IIa and IIb manual has some figure for sustained climbing from groung level to certain altitudes:

13,000 185 MPH
15,000 180 MPH
20,000 160 MPH
24,000 140 MPH
30,000 120 MPH
35,000 110 MPH

30 minutes of sustained climbing allowed, just watch your radiator temps.

Not sure if these are the figures Darryl was using for the scramble. I know he's busy but maybe he can weigh in on the figures and/ or technique.

Edit-- just tried the challenge in not very good fashion: 25 min 47 seconds! Not very good, eh?!

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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by flapman »

Just tried it in Mk. IIb and went from sea level to 20,000' MSL in 7m12s. From max forward speed (~260mph) at 6.0 PSI and 2600 RPM. Pulled for 180, then maintained that speed, slowly reducing during the climb to 140-150 passing through 20,000. Once the engine could not produce 6.0 PSI I firewalled it. Mixture was RICH.

Hope this helps.

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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Jacques »

Here are the parameters of the test as set by Darryl:

A test for you if you like.

Start next to the runway at Duxford, say just off the end.
Start timer or stop watch.
Start Spitfire manually.
Run at high idle, needle just a width below where the rpm calibration starts
Wait for at least 15 degrees oil temp AND 60 degrees radiator.
Takeoff, turn towards East coast and climb to 20,000 ft.

Post your time.

Congrats, you are now ready to pot a Hun.

By the time I got to 20,000, I was completely alone. Everyone else having already arrived to engaged their adversary and were now descending back for fuel and repairs and a bit of tea.

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Piper_EEWL
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Piper_EEWL »

That actually sounds like a fun challenge. I think I'll give that a try (but not without backing up my .dat file :wink: )
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Jacques »

I have a natural propensity to protect my aircraft....I can't help it! I will have to go through a de-sensitivation program to be able to purposely destroy my Spitfire!

On a side note, I was reading the Spitfire forum last night trying to find the above information, and was re-acquainted with just HOW much Darryl (Killratio) knows about the Spitfire and her history. He is like an encyclopedia of technical and anecdotal information on all things Spitfire. You can't really go wrong, on a rainy day, just searching his posts and reading what he has to say.

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Styggron
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Styggron »

Jacques wrote:Hi Styggron,

The Mark IIa and IIb manual has some figure for sustained climbing from groung level to certain altitudes:

13,000 185 MPH
15,000 180 MPH
20,000 160 MPH
24,000 140 MPH
30,000 120 MPH
35,000 110 MPH

30 minutes of sustained climbing allowed, just watch your radiator temps.

Not sure if these are the figures Darryl was using for the scramble. I know he's busy but maybe he can weigh in on the figures and/ or technique.

Edit-- just tried the challenge in not very good fashion: 25 min 47 seconds! Not very good, eh?!
Hello Jacques,
Oh dear, I went through the entire manual, both of them and could not find this. hmmm. Radiator temps are fine. I have not installed accu-sim on this craft, I'm happy without it so engine starting and temps may not be THAT much of an issue. I will try to overheat it though see what happens.

So with this list does it mean if I am at 13,000 speed the best I can do is 185 MPH ?
Last edited by Styggron on 02 Nov 2016, 21:12, edited 2 times in total.
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Styggron »

flapman wrote:Just tried it in Mk. IIb and went from sea level to 20,000' MSL in 7m12s. From max forward speed (~260mph) at 6.0 PSI and 2600 RPM. Pulled for 180, then maintained that speed, slowly reducing during the climb to 140-150 passing through 20,000. Once the engine could not produce 6.0 PSI I firewalled it. Mixture was RICH.

Hope this helps.
My goodness Flapmap, that time beats the real Spitfire pilot doing this. The timer needs to be started before you turn the engine on though and you have to taxi to the runway so this adds a few more minutes. I tend to start just off the runway so I have to taxi but it is short and I always save the point to keep the times consistent.

All my attempts are saved in my twitch highlights. My best is 15m 34s I think. :(

So you took off and stayed level for a while to get 260 MPH and then you went close to vertical ? My goodness this is an amazing time.
Also what does "I firewalled it" mean ?
Last edited by Styggron on 02 Nov 2016, 21:10, edited 1 time in total.
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Styggron
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Styggron »

Jacques wrote:I have a natural propensity to protect my aircraft....I can't help it! I will have to go through a de-sensitivation program to be able to purposely destroy my Spitfire!

On a side note, I was reading the Spitfire forum last night trying to find the above information, and was re-acquainted with just HOW much Darryl (Killratio) knows about the Spitfire and her history. He is like an encyclopedia of technical and anecdotal information on all things Spitfire. You can't really go wrong, on a rainy day, just searching his posts and reading what he has to say.
Don't watch my landing on The Big Trip Journey 1 video on twitch. I crashed the spitfire during landing :O I was paying too much attention to the chat window and I'm pretty sure I forgot to put the landing gear down :shock: :lol:
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by flapman »

Jacques wrote:Here are the parameters of the test as set by Darryl:
Thank you for the further information Jacques, It was a fun challenge to complete this scenario.
I have a natural propensity to protect my aircraft....I can't help it!
I actually have the opposite feelings, I feel these aircraft can be best experienced being pushed to the full limit of their abilities... regardless the costs to overhaul 70+ year old engines! Historical accuracy at any cost/risk 8)
Styggron wrote:So with this list does it mean if I am at 13,000 speed the best I can do is 185 MPH ?
My understanding is that these speeds are not the maximum speed at that altitude, but an ideal climb speed. I hesitate to call them "best rate of climb" speeds, because they're not given a such, and may be a trade off between climb rate and engine cooling needs. Your goal should be to set the recommended climb power, and then use pitch to maintain this speed. If you get a little fast, pull up a little bit, if you get slow, pitch down a little bit.
All my attempts are saved in my twitch highlights. My best is 15m 34s I think. :(
A little friendly gloating on my part, I just completed the challenge in 12m8s :mrgreen:
...and then you went close to vertical ? My goodness this is an amazing time.
Also what does "I firewalled it" mean ?
Not really, I only pitched up 30-45 degrees nose up, it gave me a good zoom through the first 3,000' or so. No need to aggressively chase a speed, let it come to you.

"Firewalled" is a general aviation term for full throttle. The vast majority of single engine aircraft have the engine mounted in the nose of the aircraft. To protect the cockpit (and pilot) from a serious fire, a full sheet of metal is vertically mounted aft of the engine. It completely covers the inside of the fuselage, with small passages for control cables, wires, and piping. It also serves as a mounting point for the engine. Since this is often directly in front of the cockpit, the term suggests pushing the throttle lever so far forward as to hit the firewall.

An automotive analogy would be the term, "floor it."

Curiously, there are numerous pictures of the Spitfire firewall online.
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From: http://www.aerovintagespares.com/avspar ... F_545.html
Last edited by flapman on 03 Nov 2016, 02:35, edited 1 time in total.

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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Killratio »

Sorry to come late to the party guys!

Thanks Jacques, you are too kind :)

The trick with performance figures, as I've often said, is that they generally only show half the story. In this case, to say "climb at 162mph" is great but HOW. Consider this:

1. Full power, flaps down and gear down, high rpm, canopy open, radiator full open, crazy climb angle = 162mph and not many FPM climb. (plus spectacular fire to follow ;) )
2. Medium power, clean profile, modest climb angle, modest rpm, radiator open part-way = 162mph and a few more FPM. (No fire....can you say "BBMF" ? )
3. As above but with podcast duties to attend to = speed 162- ish (+ or - 50mph...) and climb all over the place, 25 minutes :) :) :)
4. Rated Climb Power, Rated Climb RPM, maximum (practical) climb angle, clean profile, radiator part-way open, watching everything like a hawk, cheating on the rad temp to anything below 130/135C = 162mph, almost maximum climb rate, B.O.B Scramble ideal.
5. Rated Power, Rated climb RPM, clean profile, almost best climb angle, radiator part-way open, watching like a hawk = 140mph (from memory), maximum climb, Test Pilot's need only apply.

So Pitch plus Power equals Performance. Maximising THAT performance means using the different allowable maxima in the factors comprising THAT performance.

So with a IIb .... Watts Airscrew, +9 Boost and a climb angle which gives you the recommended climbing speed for your current altitude band.
If Rotol, +9, 2850rpm and a climb angle which gives you the recommended climbing speed for your current altitude band.

My best showing was 9 minutes 16 seconds with the Spitfire I, DeH 20PCP Airscrew. I say "best" not fastest because I have climbed faster in the Spit II but not relative to the real aircraft time to height. My II times always seem to be slightly slower than the real tests.

Just a note...I seem to recall that the ideal climbing speeds stated in the manual are something like 22mph faster than the REAL ideal. This was because the 140 odd gave great climb but at the expense of comfort, controlability, vision and therefore pilot workload. The 22mph did not make much difference to best time to altitude and so was adopted.


(BTW, during beta I tested each prop and engine combination from ground to 5K, 10K, 15K, 20K, 25K and 30K. All fell within +/- 10 or 15 seconds, which given my marginal test pilot skills, was reasonable. I only had one problem, with the Watts Airscrew on the Spitfire I. So I contacted Scott and got a fix in a few minutes, tested it and spot on. The problem.. according to my aging/ailing memory, was that Scott had missed a "point such and such" on the pitch angle of the blades!! Such is the level of Accusim processing. At that stage Scott hadn't tested the climbs (but had tested takeoff distances I believe), it was nothing more than the engine churning out power through the blades, powering the airframe through the air and giving real results! But I am a little biased...)
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Styggron »

Killratio wrote:Sorry to come late to the party guys!

Thanks Jacques, you are too kind :)

The trick with performance figures, as I've often said, is that they generally only show half the story. In this case, to say "climb at 162mph" is great but HOW. Consider this:

1. Full power, flaps down and gear down, high rpm, canopy open, radiator full open, crazy climb angle = 162mph and not many FPM climb. (plus spectacular fire to follow ;) )
2. Medium power, clean profile, modest climb angle, modest rpm, radiator open part-way = 162mph and a few more FPM. (No fire....can you say "BBMF" ? )
3. As above but with podcast duties to attend to = speed 162- ish (+ or - 50mph...) and climb all over the place, 25 minutes :) :) :)
4. Rated Climb Power, Rated Climb RPM, maximum (practical) climb angle, clean profile, radiator part-way open, watching everything like a hawk, cheating on the rad temp to anything below 130/135C = 162mph, almost maximum climb rate, B.O.B Scramble ideal.
5. Rated Power, Rated climb RPM, clean profile, almost best climb angle, radiator part-way open, watching like a hawk = 140mph (from memory), maximum climb, Test Pilot's need only apply.

So Pitch plus Power equals Performance. Maximising THAT performance means using the different allowable maxima in the factors comprising THAT performance.

So with a IIb .... Watts Airscrew, +9 Boost and a climb angle which gives you the recommended climbing speed for your current altitude band.
If Rotol, +9, 2850rpm and a climb angle which gives you the recommended climbing speed for your current altitude band.

My best showing was 9 minutes 16 seconds with the Spitfire I, DeH 20PCP Airscrew. I say "best" not fastest because I have climbed faster in the Spit II but not relative to the real aircraft time to height. My II times always seem to be slightly slower than the real tests.

Just a note...I seem to recall that the ideal climbing speeds stated in the manual are something like 22mph faster than the REAL ideal. This was because the 140 odd gave great climb but at the expense of comfort, controlability, vision and therefore pilot workload. The 22mph did not make much difference to best time to altitude and so was adopted.


(BTW, during beta I tested each prop and engine combination from ground to 5K, 10K, 15K, 20K, 25K and 30K. All fell within +/- 10 or 15 seconds, which given my marginal test pilot skills, was reasonable. I only had one problem, with the Watts Airscrew on the Spitfire I. So I contacted Scott and got a fix in a few minutes, tested it and spot on. The problem.. according to my aging/ailing memory, was that Scott had missed a "point such and such" on the pitch angle of the blades!! Such is the level of Accusim processing. At that stage Scott hadn't tested the climbs (but had tested takeoff distances I believe), it was nothing more than the engine churning out power through the blades, powering the airframe through the air and giving real results! But I am a little biased...)
Sorry KillRatio I still don't follow most of that post. One person said max throttle and 45 degrees angle and they were up in 6 or so minutes. I can never break 15 min

When Jacques wrote this (I can't find this in either of the two manuals)
13,000 185 MPH
15,000 180 MPH
20,000 160 MPH
24,000 140 MPH
30,000 120 MPH
35,000 110 MPH

Is this what I need to aim for although anything over 20,000 doesn't matter as I am trying to get to 20,000 as fast as possible.
Shouldn't I fly with a gentle climb to get speed first then for 35 dgrees, then built speed and 35 degrees again ?
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Killratio »

Ok,

The figures Jacques is quoting are for "normal" climb. Up to 15,000ft, the stated MAXIMUM climb is achieved at 160mph (but that is a "practical" maximum, given pilot skills and workload not an absolute maximum achievable, which is actually at 140mph. )

You are using the Watts fixed still, aren't you? So for a Scramble climb you are looking for "maximum practical" not "normal".

The *best* way is:

1. Take off using full throttle. Get gear up straight away. Radiator closed to 1 notch FORWARD of the red triangle. (position 3)

2. Accelerate to about 180mph and then reduce throttle to give 9 lb per sq in boost. "past the 8 on the gauge by a bit".(EDIT : I am not sure how much boost is achievable with the Watts at 162mph in the II...so read HIGHEST BOOST POSSIBLE but not MORE than 9, everywhere!)

3. Pull-up firmly but not violently until your speed falls to 162mph and adjust nose angle so that it stays at 162mph. You may need to adjust the throttle up a bit again to 9psi.

4. STAY THERE. Do not wander the nose around, do not let the speed get greatly above or below 162. Do not let the boost fall below 9. Keep opening, progressively, the throttle a bit after about 10K to keep at 9psi. After 13k-14K and when the throttle is fully open, the boost will drop below 9 progressively as you climb ...and keep dropping. At that point adjust the nose angle to keep the speed at 162 and KEEP the boost AS HIGH AS IT WILL GO.

"4" is what makes it a challenge. It is not a matter of pointing the nose at 20,000ft and going...that would not require anything "challenging". Pilot skill is what will give you the time CLOSEST to the real figure. Every minute slower than the published time is indicative of something you are doing which is "sub optimal". For example, on your Twitch broadcasts, the speed and climb rate wander all over the place. It's all good fun...but that is what makes the difference between 6 minutes and 15 minutes.

I can do better than the above 1-4 will give as a result because I will use 140mph and peg that pretty much exactly all the way up BUT.. one mess up on power, or nose angle, or heaven forbid, a stall..and it's all over. That's why the manual recommends the "normal" climb speeds. They do not take the aircraft to the edge of controlability and allow the pilot to concentrate on other things like his leader, the sky around and not getting killed.

I can't tell you an angle, I'm not paying any attention to that, I'm making sure my engine is performing to max, my speed is right on the money and I am TAKING the performance that that gives. The Climb rate in FPM is another one I can't give you...because it is constantly changing during the climb. IT is the result of the things that are important to achieving the goal. If you achieve 6000fpm in a zoom climb from 280mph for 10 seconds, that is very pretty but in the context of a 7-8 minute climb to 20,000ft , it won't actually achieve mush if anything more than a measured assumption EARLIER of a 162mph climb.

Height in time... here that is the goal. Now if you were to ask my how do I clear that mountain at the end of the runway, then ANGLE of climb becomes the most important and Height in DISTANCE is the main game. Slower speed, steeper angle AND I want the backs of the airscrew blades to be knocking against my fingers on the front of the throttle lever!!! :)
.

Most important thing for the Scramble Challenge is maximum power allowable, speed right on 162mph in the climb and CONSISTENCY.


;)

Darryl
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Piper_EEWL
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by Piper_EEWL »

Just tried this two times with the MkII with the Rotol constant speed prop. Including startup and warming the engine (which took about 2 minutes) and it worked quite well. Got up to 20kft in 9:32 and 9:20. Without overheating I might add. I'm pretty suprised it worked that well with the engine temps.

It's a fun challenge. I might give it another try with the fixed pitch prop.
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Re: Help with fast climb - can't break 15 minutes to 20,000

Post by flapman »

Piper_EEWL wrote:Just tried this two times with the MkII with the Rotol constant speed prop. Including startup and warming the engine (which took about 2 minutes) and it worked quite well. Got up to 20kft in 9:32 and 9:20.
What grade of fuel do you use, and what PSI/RPM?

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