I don't think they needed the power for takeoff because the "catapult" in this context was a whacking great rocket.

Given the stability & control difficulties associated with using really high powers at low speeds in these aeroplanes, and the obvious risk of engine failure at low speed & altitude off the bow of a ship which probably can't stop or avoid the aeroplane if it ends up in the drink, I would have thought it more likely that the launch was conducted at normal takeoff power.

I think that the extra combat power was primarily intended to be used for a rapid climb to cloudbase in order to intercept/scare off the bomber that was threatening their convoy; in the absence of RADAR, the CAM's fighter was only launched when the enemy was within visual range, and so warning time was strictly limited.

The climb would be unlikely to go higher than cloudbase because the bomber would just cloud-hop home (and probably couldn't hit a ship from any higher anyway, so either way it would be a mission kill); the fighter would be unlikely to give chase because of the obvious navigational challenge of finding their convoy again afterwards in an aeroplane not really equipped for naval navigation (at this time, most Fleet Air Arm aircraft, even the fighters, had a navigator).

For this reason, I suspect that they'd be unlikely to use the extra power for more than a couple of minutes in the sortie; I'm guessing that an early Hurricane with +16 would probably exceed 3000 fpm climb rate, and the cloud base would usually be less than 6000 feet...

That low I would think you needed all the power to maintain flight even with a catapult. You only have a few feet until your in the drink.

It would be worth it to accelerate the aircraft quickly to flying speeds and then returning the engine to less catastrophic power levels.

You think? I know climbing is the most demanding portion of flight on an engine and it is the time period an engine is most vulnerable to detonation. Such an extreme level of over-boost is begging for detonation in a climb out.

By nature, aircraft engines are high output to weight and very vulnerable to detonation failures. Even with a disposable aircraft, the few minutes climbing in detonation scenario would make the accomplishment of the aircraft's intercept mission unlikely. A normal Hurricane will catch a Condor so I don't see the risk for the reward in it.

Here is a typical aircraft engine failure due to detonation scenario. Here one cylinder begins detonating and the motor makes it another 9 minutes before giving up the ghost.

http://www.to-avionics.com/insight/case.html


Even with modern steam catapults, it is typical to launch at full power with afterburner.

http://www.youtube.com/watch?v=lbbSYb7kDLY

Anyway, it is all speculation until someone comes up with a Sea Hurricane POH!!

BoB museum or the Shuttleworth collection had one I think some years ago in flight condition.

I don't think that CAM ship needed any boosted or special aircraft to be proteced.

Remember that they needed to down reconnaissance Condor that were monitoring the convoy.

I have in memory the story of Hurri being converted from coastal command (and those were not new Hurri) and then moved on teh CAM ship mission.

Also there was only a handful of pilots qualified for that particular exercise (something like 22 - not sure). I read the story of one that did 3 mission (bailing out two time in teh sea and being knocked down once while running to his plane during an alert).

Can't remember the title but as I think he was an ex wingman of Bader, probably the story might be somewhere in Bader story.

Anyway, giving the weary airframe and the dangerous mission with flight in bad weather (when the U-boat were attacking with the Condor coordinating or recognizing the target for the wolf pack) it's un-likely that they played with some tricky eng mods just to gain 20 sec in a climb to cloud base as was alrdy pointed out.

3000ft/min is a huge climb rate. The 109 managed to maintain that one during the war despite her overweight and still was considered one of the best climber at the end.

I am sry to be so contradictory.

Nice to see you back Vip !

AFAIK this is a complete list of CAM launches:

http://en.wikipedia.org/wiki/CAM_ship

Late war fighters were generally somewhere in the 3500-5000 fpm range. For example, here's some data for the 109G from a source not exactly noted for "blue bias":

http://www.wwiiaircraftperformance.o...tt-german.html

The P-51 wasn't really known for its climb performance, but its low level ROC in WEP is over 3000 fpm at combat weight for all models at 5000 feet:

http://www.wwiiaircraftperformance.o...ical-chart.jpg

Meanwhile, the mighty Spitfire IX would exceed 3000 fpm at 20,000 feet at +18 psi in 1943:

http://www.spitfireperformance.com/spitfire-IX.html

Thanks.

Ok I am more in the average climb rate regarding time to 6Km or 20kft

That said 5000ftm seemed impressive to me with a calculated time of 4 min to 20kft witch I hve never heard about ;)

Regarding CAM launches, well you know how stories goes... I hve to dig the book and see.

:-)

Hi guys,

I hve in mind that some of you are waiting for my answer (yeah I am that selfish).

However I took some time to re-read some of my earlier post since I am a newborn on CoD forum in the last couple of days and I am pretty sure that I did alrdy give the arguments you cld be waiting for.

Look, for height , wide open throttle, Supercharging and 2nd thermodynamic principle...

Have fun !

A supercharger that can produce 12lb boost at 10000 feet (~full throttle altitude for a Merlin III) can produce about 17lb boost at sea level. A fairly accurate estimate is really simple maths, just divide boost at altitude by pressure at altitude in atmos, in this case ~0.7.

Doesn't mean the engine can handle it.

Sea Hurricanes modified for 16lb were not throwaway planes, they were primarily used from carriers with the full intend of repeated use and to my knowledge only from 1942 onwards with the 16lb boost.

Ok here we go again

Merlin XX from RR doc WOT at 15000 9lb

What means WOT ? At tht height : max flow = max ro *V

At sea level ro > ro at alt

then ro* V max is LESS (max ur eng can handle)

SO less OT -> less Flow -> less air -> less fuel -> less SHP -> less flywheel rpm (THX mother nature or there will had been a prob) -> less max theo HP

By teh way as I hev alrdy raised soem of your dat (Spitdotcom atc...) are confusing abt HP and SHP as testing was done static without S/C (tht's all abt the source I hve)

As you can see the only way to outsource the most HP of a Merlin in that conditions is to have variable geo (for ex the size of the ducting). It's all abt the Merlin for low alt , the Merlin for med alt and the Merlin for high alt.... Does is sound anything like familiar to you ?

Oh and by the way I didn't mention here the temp raise you'd get in the conversion. But I am sure you'd get enough time for a forum search. Some hve been down to the details more than me (I hve in mind some Crump's posts). Feel free to read them too.

Huh Yeah pls devs give them their 12lb now tht they will be left with 2lb only late Spits when you'll do that 44 add-on :rolleyes:

Massive arrogance.

I'm still working on the "catch it or go without it".