WW2 with no Spitfire - Hurricane being primary interceptor

[FLYBOYJ]

The Spitfire required specialized tooling, manufacturing techniques and skill sets that the Hurricane didn't.

Care to tell us what those specifically are?

The Hurricane was certainly easier to build but there was nothing special about the spitfire when comparing construction of other skin-stressed semi aluminum aircraft of the period.

 

[RCAFson]

According to http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Merlin.pdf

Merlin 45 rated altitude 11,000ft = 1515hp.
Merlin XX rated altitude 6,000ft = 1480hp (MS), 12,500ft = 1480hp (FS).

What's the betting that if the FTH of the XX was brought back to 11,000ft it would make 1515hp too?

(outputs with 54.5inHg boost)

That's the static rating, but a single speed SC was more efficient than a two speed, leading to a higher rated output at the same boost albeit at only a single altitude.

 

[wuzak]

That's the static rating, but a single speed SC was more efficient than a two speed, leading to a higher rated output at the same boost albeit at only a single altitude.

How is a single speed more efficient than a two speed, considering that:

• They have the same supercharger impeller
• They have the same supercharger housing/volute
• They used the same intake elbow
• They had the same carburettor

Assuming that the top gear in the 2 speed drive is the same as the gear in the single speed drive, how would output be any different between the two once the 2 speed engine is in FS gear?

 

[The Basket]

No Spitfire=mass panic buying of P~40s

Highly speculative...of course....this is what this is.

A vacuum is created with no Spitfire and what fillls it...i would buy or build something....speculative.

I wonder if Fairey could build a single seat fighter based on the Battle...

 

[Shortround6]

You are, of course, joking?

 

[The Basket]

You are, of course, joking?

I never joke when it comes to defence of my beloved country. I will fight them on the beaches and I will never surrender.

 

[Tante Ju]

Assuming that the top gear in the 2 speed drive is the same as the gear in the single speed drive, how would output be any different between the two once the 2 speed engine is in FS gear?

I believe there is some (very small) mechanical loss in any gearbox, which increases as new gears (supercharger speed) is added to it.

 

[Aozora]

That's the static rating, but a single speed SC was more efficient than a two speed, leading to a higher rated output at the same boost albeit at only a single altitude.

By your reckoning Fighter Command would have been lumbered with an already semi-obsolescent design powered by a semi obsolescent single speed engine when two speed engines and more advanced airframes were available.

 

[Aozora]

C'mon you've done enough reading to understand that the more complex the aircraft the lower it's servicabilty rates are when operating from primitive bases.

You have made more than a few sweeping claims without evidence - show us some facts and figures to back your claims up.

That Hurricane was overloaded just for trials. a late model Hurricane 1 came to 6793 lbs with full fuel but a variation of 100lbs is probably not unusual. A HHIIA was probably ~7100lbs.

Please prove that the Hurricane was overloaded for trials and explain how you know this.

 

[wuzak]

I believe there is some (very small) mechanical loss in any gearbox, which increases as new gears (supercharger speed) is added to it.

I don't believe the Merlin reduction gearbox was like a car gearbox - that is, the unusued gears in teh Merlin Gearbox are not in motion.

And it they did, the only loss would be bearing friction - which would be almost negligible. ie couldn't tell the difference in power.

The main losses in gearboxes is in the meshing of gears. This is proportional to the power being transmitted through them. This power would be the same for both the 45 and XX, given the same top ratio.

So, in short, I don't think the 2 speed drive would lose that much, if any at all.

 

[wuzak]

This chart

http://www.wwiiaircraftperformance.org/hurricane/merlin-xx-curve-c1.jpg

Shows a maximum of 1480hp @ 6,250ft MS gear and 1440hp @ 11,000ft FS gear. Notably, after FTH in MS gear the power drops to 1400hp @ 8,000ft, before the gear change sees the power rising to FTH in MS gear.

 

[Shortround6]

I never joke when it comes to defence of my beloved country. I will fight them on the beaches and I will never surrender.

You build fighters based on the Battle and you WILL be fighting them on the beaches. You would be better of fixing up every Gloster Gauntlet you could find.

 

[Shortround6]

I believe there is some (very small) mechanical loss in any gearbox, which increases as new gears (supercharger speed) is added to it.

Not really, there is a small mechanical loss in ANY gear set. However the difference in power lost in any ONE gear set compared to another is going to be minuscule if it exists at all. Power lost in rotating gears that ARE NOT engaged is also going to be minuscule. Do you want a one speed transmission in your car or bicycle compared to a two speed because it is more "efficient" in theory?

 

[FLYBOYJ]

C'mon you've done enough reading to understand that the more complex the aircraft the lower it's servicabilty rates are when operating from primitive bases.

I think what you're fishing for is something called a "Mission Capable" or "MC" rate and this has nothing to do with how complex the aircraft is or where its operating from...

 

[Shortround6]

C'mon you've done enough reading to understand that the more complex the aircraft the lower it's servicabilty rates are when operating from primitive bases.

This may be partially true. A Fowler flap may be more likely to get out of order or take longer to service than a split flap. A plane with 2 doors for each landing gear will take more maintenance than a plane with one door per landing gear.

But to stretch that to a plane with an all metal tube for a fuselage requires more maintenance or is more likely to get out of order than a steel tube box girder covered in wood formers and fabric is quite a leap. Once the all metal tube fuselage is manufactured what do you have to do to it? There are NO moving parts.

Get a couple of small caliber bullet holes in it? Crude patch with muzzle tape or fabric. Or small metal patch, not panel replacement.

 

[FLYBOYJ]

This may be partially true. A Fowler flap may be more likely to get out of order or take longer to service than a split flap. A plane with 2 doors for each landing gear will take more maintenance than a plane with one door per landing gear.

But to stretch that to a plane with an all metal tube for a fuselage requires more maintenance or is more likely to get out of order than a steel tube box girder covered in wood formers and fabric is quite a leap. Once the all metal tube fuselage is manufactured what do you have to do to it? There are NO moving parts.

Get a couple of small caliber bullet holes in it? Crude patch with muzzle tape or fabric. Or small metal patch, not panel replacement.

It's not as simplistic as that. Small fabric holes are easier to repair than sheet metal. Damage to the tubing may be repaired by welding splices or gussets around the damage area. If it's in a larger load bearing area you'll have to do some extensive welding which means removing large portions if not all the fabric covering. When re-installing fabric, it needs to be done in a temperature controlled area with low humidity.

 

[RCAFson]

You have made more than a few sweeping claims without evidence - show us some facts and figures to back your claims up.

I provided a quote from Mason showing that even in the UK, that Spitfires often had to be trucked out for repairs from less developed based, while Hurricanes with similar damage could be repaired on site. The Hurricane used a construction method that was used for several decades prior to WW2 and therefore base service personnel even in the MTO were familiar with it, but even in the UK they were not universally familiar with stressed skin monocoque airframes.

Please prove that the Hurricane was overloaded for trials and explain how you know this.

I read it in a report entitled:
"Comparative Performance Trials under Normal and Overload conditions"

 

[RCAFson]

How is a single speed more efficient than a two speed, considering that:

• They have the same supercharger impeller
• They have the same supercharger housing/volute
• They used the same intake elbow
• They had the same carburettor

Assuming that the top gear in the 2 speed drive is the same as the gear in the single speed drive, how would output be any different between the two once the 2 speed engine is in FS gear?

The gear ratios were not the same, but as we've discussed, the gear change leads to a loss in power because it has to be throttled back prior to gear changing, plus there is the additional weight and complication of the two speed gear box with it's attendant reliability issues, which is probably why the 45 was rated for 16lb boost almost a year sooner than than the XX. Additionally, the gear ratio of the 45 was better suited for medium altitude where much of the fighting took place but the main advantage was the simpler engine management with increased reliability, but as always the XX will not go away, but as there will be a lot more Hurricanes, both engines will be needed to meet demand, and for differing roles.

 

[FLYBOYJ]

I provided a quote from Mason showing that even in the UK, that Spitfires often had to be trucked out for repairs from less developed based, while Hurricanes with similar damage could be repaired on site. The Hurricane used a construction method that was used for several decades prior to WW2 and therefore base service personnel even in the MTO were familiar with it, but even in the UK they were not universally familiar with stressed skin monocoque airframes.

This is highly speculative - sheet metal repair skills were easily learned. Fabric aircraft can be easily repaired if no primary structure is damaged. One would have to look at at case by case comparison to determine the extent of damamge to all aircraft to make a real conclusion. As mentioned earlier, if large sections of fabric had to be replaced, this had to be done under controlled conditions. I could spell out for you what would happen if you tried to cover a fabric aircraft in temperatures too cold or too humid.....

Was Mason an aircraft mechanic???

 

[The Basket]

You build fighters based on the Battle and you WILL be fighting them on the beaches. You would be better of fixing up every Gloster Gauntlet you could find.

If the Germans could invade and that's a big if.

My point is that there were a nunber of aircraft manufacturers...back in the day....who could build a merlin powered single seat machine.

Supermarine was one of many so as per my thoughts ask Fairey as they have experience with metal machines.